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Show Area Forecast Discussion - Charleston, SC (Charleston, SC Area) Selection: |
| #514609 (Received by flhurricane at: 10:33 PM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1031 PM EDT TUE MAY 29 2012 .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE UP THE SOUTHEAST COASTLINE TONIGHT...BEFORE SHIFTING WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... TROPICAL DEPRESSION BERYL WILL STEADILY TRACK NORTHEAST DIRECTLY OVER THE FORECAST AREA OVERNIGHT. ASSOCIATED RAIN BANDS ARE BRINGING HEAVY DOWNPOURS FROM THE SAVANNAH RIVER NORTHWARD. THE LATEST UPPER AIR SOUNDING FROM CHS INDICATES PWAT VALUES OVER 2 INCHES...AND WHEN COMBINED WITH STRONG CONVERGENCE AND UPPER LEVEL SUPPORT...EXPECT THE HEAVY RAIN THREAT TO CONTINUE THROUGH THE EARLY MORNING HOURS NORTH OF INTERSTATE 16. MOST SIGNIFICANT RAIN COVERAGE WILL BE LIFTING INTO SOUTH CAROLINA COUNTIES...WHERE THE BEST CONFLUENCE OFF THE ATLANTIC WILL OCCUR. HAVE INDICATED RAIN CHANCES DIMINISHING FROM SOUTHWEST TO NORTHEAST THROUGH 6 AM...AS THE STEADIEST RAINS WILL HAVE ENDED FOR SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH CAROLINA. LATEST MESOANALYSIS INDICATES ENHANCED HELICITY AND SHEAR NORTH OF THE CENTER OF CIRCULATION BY 01Z...SUGGESTING A CONTINUED THREAT FOR ISOLATED TORNADOES WITHIN SHOWER ACTIVITY. GUSTY WINDS...ESPECIALLY WITHIN ENHANCED RAIN BANDS...ARE POSSIBLE THROUGH THE EARLY MORNING HOURS. SOUTHEAST WINDS COULD GUST ABOVE 30 MPH AT TIMES. FORECAST TEMPERATURES LOOK ON TRACK WITH HOURLY TRENDS. THE TROPICAL AIR MASS WILL LIMIT TEMPS TONIGHT TO NO LOWER THAN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... WEDNESDAY AND WEDNESDAY NIGHT...THE CENTER OF BERYLS CIRCULATION WILL BE POSITIONED JUST OUTSIDE OF THE FORECAST AREA IN THE MORNING. A COLD FRONT WILL APPROACH FROM THE NORTHWEST AND WILL HELP TO DRAW BERYL TO THE NORTHEAST AND AWAY FROM THE AREA. IN THE WAKE OF BERYL AND AS THE WEAK FRONT MOVES IN...MUCH DRIER AIR WILL BEGIN FILTERING INTO SOUTHERN SC AND SOUTHEAST GA. IN FACT WE WILL START THE DAY WITH PWATS NEAR 2 INCHES ACROSS THE TRI-COUNTY AND 1.5 INCHES ELSEWHERE...DECREASING TO LESS THAN 1.25 INCHES EVERYWHERE OVERNIGHT. RAINFALL CHANCES FOR WEDNESDAY WILL PRIMARILY BE ASSOCIATED WITH THE DEPARTURE OF BERYL...AND WE CONTINUE TO HANG ON TO CHANCE TO LIKELY POPS FOR THE FAR NORTHEAST CORNER OF THE FORECAST AREA FOR A COUPLE OF HOURS IN THE MORNING. THEREAFTER...THERE IS SOME POTENTIAL FOR ISOLATED DIURNAL SHOWERS/STORMS ACROSS SOUTHEAST GA. AS CLOUDS CLEAR OUT THROUGH THE DAY AMPLE INSOLATION...DOWNSLOPE FLOW...AND WARM LOW LEVEL THICKNESSES WILL SUPPORT AFTERNOON HIGHS IN THE UPPER 80S TO LOW 90S. THE OVERNIGHT PERIOD WILL BE QUIET WITH LOWS FALLING INTO THE UPPER 60S INLAND AND LOW 70S ALONG THE COAST. THURSDAY THROUGH FRIDAY...THE FORECAST AREA WILL BE UNDER A RATHER NEBULOUS UPPER PATTERN THURSDAY AHEAD OF A VIGOROUS TROF AND UPPER LOW DIGGING INTO THE UPPER MIDWEST. THE FRONT THAT MOVED THROUGH ON WEDNESDAY WILL REMAIN JUST TO THE SOUTH WITH DRY AIR GENERALLY IN PLACE. THE FRONT WILL LIFT BACK TO THE NORTH LATE IN THE DAY AND MAY PROVIDE ENOUGH INCREASE IN MOISTURE TO SUPPORT ISOLATED/SCATTERED SHOWERS/STORMS PRIMARILY ACROSS SOUTHEAST GA. THE MAIN STORY FOR THURSDAY WILL BE THE WARM TEMPERATURES. LOW LEVEL THICKNESSES INCREASE FROM WEDNESDAY AND WILL SUPPORT HIGHS IN THE LOW TO MID 90S PRIOR TO THE SEA BREEZE MOVING THROUGH. THE SEA BREEZE SHOULD BE PRETTY VIGOROUS WITHIN THE DEVELOPING SOUTHERLY FLOW OUT AHEAD OF A COLD FRONT ORGANIZING TO THE WEST. THE STRONG UPPER TROF AND CLOSED LOW WILL MOVE INTO THE GREAT LAKES ON FRIDAY WITH A NORTHERLY UPPER JET ON THE EAST SIDE OF THE TROF AXIS. CURRENT MODEL TIMING FOR THE FRONT CONTINUES TO BE A BIT MIXED...BUT GENERALLY FAVORS BRINGING THE FRONT IN FROM THE WEST LATE FRIDAY NIGHT. INCREASING UPPER SUPPORT AND AFTERNOON HEATING WILL SUPPORT AT LEAST SCATTERED COVERAGE OF SHOWERS/STORMS FRIDAY AFTERNOON/EVENING IN ADVANCE OF THE FRONT. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... COMPLEXITY OF THE WEATHER PATTERN ACROSS THE COASTAL CORRIDOR OVERNIGHT IS AT A VERY HIGH LEVEL...WITH TROPICAL DEPRESSION BERYL WOBBLING RIGHT THROUGH THE REGION. SHIFTING SURFACE WINDS...PERIODIC IFR CIGS AND VSBYS...AND POTENTIAL LOW LEVEL WIND SHEAR CAN BE EXPECTED AT THE TERMINALS OVERNIGHT UNTIL BERYL PASSES. LOCALLY HEAVY DOWNPOURS ARE QUITE LIKELY THROUGH THE OVERNIGHT PERIOD...ESPECIALLY AT KCHS AS RAIN BANDS SHIFT NORTHWARD. ON WEDNESDAY...EXPECT IMPROVING CONDITIONS AFTER MID MORNING WITH A RETURN TO VFR CONDITIONS AND NW SURFACE WINDS MAINLY BELOW 15 KT. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL. A COLD FRONT WILL CROSS THE REGION LATE FRIDAY THROUGH EARLY SATURDAY. && .MARINE... TONIGHT...THE MARINE COMMUNITY WILL BE IMPACTED YET AGAIN BY BERYL...AS THE DEPRESSION PASSES NORTHEAST ACROSS THE ADJACENT COASTLINE THROUGH THE OVERNIGHT PERIOD. WILL MAINTAIN ONGOING TRACK TIMING THAT SUGGESTS THE SYSTEM WILL APPROACH THE SOUTH SANTEE RIVER AROUND OR SHORTLY AFTER DAYBREAK. A STRONG PRESSURE GRADIENT AROUND BERYL...COMBINED WITH ENHANCED WINDS WITHIN RAIN BANDS...WILL GENERATE SOUTHERLY WINDS 20 TO 25 KT...WITH GUSTS TO 30 KT. OCCASIONAL HIGHER GUSTS TO 35 KT ARE POSSIBLE...HOWEVER THE FREQUENCY WILL NOT BE SUFFICIENT TO JUSTIFY HEADLINES HIGHER THAN A STRONGLY WORDED SMALL CRAFT ADVISORY FOR ALL WATERS. SEAS WILL BUILD TO 5 TO 9 FT...TRENDING HIGHER FARTHER FROM THE COASTLINE. IN ADDITION...THE VEERING LOW LEVEL WINDS IN THE ATMOSPHERE WILL SUPPORT A RISK FOR ISOLATED TORNADIC WATERSPOUTS THROUGH THE NIGHT. BASED ON THESE CONDITIONS...MARINERS ARE STRONGLY CAUTIONED TO NAVIGATE WITH EXTREME CARE IF OUT IN THE COASTAL WATERS. WEDNESDAY THROUGH SUNDAY...TD BERYL IS EXPECTED TO BE POSITIONED JUST INLAND AND VERY CLOSE TO THE CHARLESTON COUNTY WATERS WEDNESDAY MORNING. THE SYSTEM MAY BE IN THE PROCESS OF DEEPENING AT THIS TIME AND A TIGHT PRESSURE GRADIENT WILL BE IN PLACE ACROSS MUCH OF THE WATERS. WINDS WILL BE OUT OF THE NW AND WILL LIKELY BE SUPPORTIVE OF SCA CONDITIONS THROUGH MID/LATE MORNING FOR PORTIONS OF THE AREA. BERYL WILL THEN MOVE STEADILY AWAY THROUGH THE DAY AND WINDS/SEAS WILL IMPROVE. THE PATTERN WILL THEN BECOME QUITE THURSDAY INTO FRIDAY AHEAD OF AN APPROACHING FRONT. THE COLD FRONT IS EXPECTED TO CROSS THE WATERS LATE FRIDAY/EARLY SATURDAY...BUT AT THIS POINT SCA/S ARE NOT LIKELY. && .HYDROLOGY... HEAVY RAIN WILL SHIFT NORTHWARD AS THE NIGHT PROGRESSES...AND HAVE THUS MAINTAINED A FLASH FLOOD WATCH FOR SOUTH CAROLINA THROUGH EARLY WEDNESDAY. STRONG LOW LEVEL CONVERGENCE AND FORCING FOR ASCENT WITHIN PWAT VALUES GREATER THAN 2 INCHES WILL SUPPORT A CONTINUED RISK FOR HEAVY RAIN IN PARTS OF SOUTH CAROLINA. AT LEAST 2 TO 4 INCHES OF RAINFALL ARE EXPECTED...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF MORE PERSISTENT RAIN BANDS DEVELOP AND TRAINING OCCURS...ESPECIALLY OVER THE CHARLESTON TRI-COUNTY AREA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...FLASH FLOOD WATCH UNTIL 6 AM EDT WEDNESDAY FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ330. && $$ |
| #514560 (Received by flhurricane at: 7:56 PM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 756 PM EDT TUE MAY 29 2012 .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE NORTHEASTWARD ALONG THE SOUTHEAST COASTLINE TONIGHT. BERYL WILL THEN MOVE WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... WE/RE NOT DONE WITH BERYL JUST YET...AS SHE CONTINUES TO MOVE NE AND WILL BE FOUND APPROACHING THE ALTAMAHA RIVER THIS EVENING...THE SAVANNAH RIVER BY MIDNIGHT...THEN APPROACHING OUR NORTHERN ZONES VERY LATE TONIGHT. THIS SYSTEM WILL BRING WITH IT THE RISK OF ISOLATED TORNADOES AND PERIODS OF HEAVY RAINFALL. AS BERYL CONTINUES HER TREK OFF TO THE NE...STRONG LOW LEVEL CONVERGENCE WILL BECOME ENHANCED TONIGHT AS THE CYCLONIC CIRCULATION TRAVERSES THE LOCAL AREA. STRONG UPWARD VERTICAL VELOCITIES ALONG WITH THE RIGHT REAR QUAD OF THE UPPER LEVEL JET PASSING NOT TOO FAR TO THE NW AND STEADY HEIGHT FALLS WILL FURTHER ENHANCE LARGE SCALE ASCENT. WHEN YOU COMBINE THIS WITH PWATS THAT ARE NEAR THE 99TH PERCENTILE FOR LATE MAY WE/RE LOOKING AT SO VERY MUCH NEEDED RAINS. WHILE SE GA WILL GET UP TO ANOTHER 1/2 TO 1 INCH...THE BULK OF THE HEAVIEST RAINS TONIGHT WILL IMPACT SOUTHERN SC WHERE THE BEST CONFLUENCE OFF THE ATLANTIC WILL OCCUR. SEE THE HYDROLOGY SECTION BELOW FOR ADDITIONAL DETAILS. RAIN PROBABILITIES WILL BE NEAR 100 PERCENT OVER ALL OF SOUTHERN SC...AROUND 90 PERCENT NEAR THE SAVANNAH RIVER IN SE GA...TRENDING DOWN TO 60 PERCENT NEAR THE ALTAMAHA RIVER. THE EVENING RUSH HOUR WILL BE WET FOR JUST ABOUT EVERYONE...WHILE THE MOST LIKELY TIMING FOR THE HEAVIEST RAINS IN SC TO OCCUR FROM ABOUT 10 PM TO 4 AM. BY LATE TONIGHT POPS WILL BEGIN DIMINISHING FROM SW TO NE AND BY 6 AM THE STEADIEST RAINS WILL HAVE ENDED FOR SE GA AND FAR SOUTHERN SC. IN REGARDS TO THE POTENTIAL FOR TORNADOES...THERE IS CONSIDERABLE HELICITY WITHIN THE LOW LEVELS OF THE ATMOSPHERE. THAT ALONG WITH VORTICITY GENERATION PARAMETERS APPROACHING 0.2 AND 0-6 KM BULK SHEAR OF 30-35 KT SUGGESTS THAT GIVEN THAT BERYL WILL TRAVEL OVER THE AREA...THERE DOES REMAIN THE RISK OF ISOLATED TORNADOES UNTIL LATE. THE TROPICAL AIR MASS WILL LIMIT TEMPS TONIGHT TO NO LOWER THAN THE UPPER 60S AND LOWER 70S. IT IS WORTH NOTING THAT WINDS WITHIN THE FIRST 2500 FEET ARE AS HIGH AS 35-45 KT. WHILE NOT ALL OF THAT WILL MIX DOWN TONIGHT...WE WILL NEED TO CLOSELY KEEP WATCH FOR A MARGINAL WIND ADVISORY FOR CHARLESTON...COASTAL COLLETON...BEAUFORT AND MAYBE DORCHESTER AND BERKELEY COUNTIES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... WEDNESDAY AND WEDNESDAY NIGHT...BASED ON THE 11AM NHC TRACK FORECAST FOR TD BERYL...ITS CENTER OF CIRCULATION WILL BE POSITIONED JUST OUTSIDE OF THE FORECAST AREA IN THE MORNING. A COLD FRONT WILL APPROACH FROM THE NORTHWEST AND WILL HELP TO DRAW BERYL TO THE NORTHEAST AND AWAY FROM THE AREA. IN THE WAKE OF BERYL AND AS THE WEAK FRONT MOVES IN...MUCH DRIER AIR WILL BEGIN FILTERING INTO SOUTHERN SC AND SOUTHEAST GA. IN FACT WE WILL START THE DAY WITH PWATS NEAR 2 INCHES ACROSS THE TRI-COUNTY AND 1.5 INCHES ELSEWHERE...DECREASING TO LESS THAN 1.25 INCHES EVERYWHERE OVERNIGHT. RAINFALL CHANCES FOR WEDNESDAY WILL PRIMARILY BE ASSOCIATED WITH THE DEPARTURE OF BERYL...AND WE CONTINUE TO HANG ON TO CHANCE TO LIKELY POPS FOR THE FAR NORTHEAST CORNER OF THE FORECAST AREA FOR A COUPLE OF HOURS IN THE MORNING. THEREAFTER...THERE IS SOME POTENTIAL FOR ISOLATED DIURNAL SHOWERS/STORMS ACROSS SOUTHEAST GA. AS CLOUDS CLEAR OUT THROUGH THE DAY AMPLE INSOLATION...DOWNSLOPE FLOW...AND WARM LOW LEVEL THICKNESSES WILL SUPPORT AFTERNOON HIGHS IN THE UPPER 80S TO LOW 90S. THE OVERNIGHT PERIOD WILL BE QUIET WITH LOWS FALLING INTO THE UPPER 60S INLAND AND LOW 70S ALONG THE COAST. THURSDAY THROUGH FRIDAY...THE FORECAST AREA WILL BE UNDER A RATHER NEBULOUS UPPER PATTERN THURSDAY AHEAD OF A VIGOROUS TROF AND UPPER LOW DIGGING INTO THE UPPER MIDWEST. THE FRONT THAT MOVED THROUGH ON WEDNESDAY WILL REMAIN JUST TO THE SOUTH WITH DRY AIR GENERALLY IN PLACE. THE FRONT WILL LIFT BACK TO THE NORTH LATE IN THE DAY AND MAY PROVIDE ENOUGH INCREASE IN MOISTURE TO SUPPORT ISOLATED/SCATTERED SHOWERS/STORMS PRIMARILY ACROSS SOUTHEAST GA. THE MAIN STORY FOR THURSDAY WILL BE THE WARM TEMPERATURES. LOW LEVEL THICKNESSES INCREASE FROM WEDNESDAY AND WILL SUPPORT HIGHS IN THE LOW TO MID 90S PRIOR TO THE SEA BREEZE MOVING THROUGH. THE SEA BREEZE SHOULD BE PRETTY VIGOROUS WITHIN THE DEVELOPING SOUTHERLY FLOW OUT AHEAD OF A COLD FRONT ORGANIZING TO THE WEST. THE STRONG UPPER TROF AND CLOSED LOW WILL MOVE INTO THE GREAT LAKES ON FRIDAY WITH A NORTHERLY UPPER JET ON THE EAST SIDE OF THE TROF AXIS. CURRENT MODEL TIMING FOR THE FRONT CONTINUES TO BE A BIT MIXED...BUT GENERALLY FAVORS BRINGING THE FRONT IN FROM THE WEST LATE FRIDAY NIGHT. INCREASING UPPER SUPPORT AND AFTERNOON HEATING WILL SUPPORT AT LEAST SCATTERED COVERAGE OF SHOWERS/STORMS FRIDAY AFTERNOON/EVENING IN ADVANCE OF THE FRONT. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... COMPLEXITY OF THE WEATHER PATTERN ACROSS THE COASTAL CORRIDOR OVERNIGHT IS AT A VERY HIGH LEVEL WITH TD BERYL WOBBLING RIGHT THROUGH THE REGION. SHIFTING SURFACE WINDS...PERIODIC IFR CIGS AND VSBYS...AND POTENTIAL BOUTS WILL LLWS CAN BE EXPECTED AT THE TERMINALS OVERNIGHT UNTIL BERYL PASSES BY. LOCALLY HEAVY DOWNPOUR A GOOD BET A KSAV EARLY THIS EVENING AND KCHS FOR A GOOD PART OF THE OVERNIGHT. ON WED...EXPECT IMPROVING CONDITIONS AFTER MID MORNING WITH A RETURN TO VFR CONDITIONS AND NW SURFACE WINDS MAINLY BELOW 15 KT. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL. A COLD FRONT WILL CROSS THE REGION LATE FRIDAY THROUGH EARLY SATURDAY. && .MARINE... TONIGHT...THE MARINE COMMUNITY WILL BE IMPACTED YET AGAIN BY BERYL...AS SHE WILL RETURN ON THE REBOUND...PASSING NE OVER THE NEARBY PORTION OF SC AFTER 9 OR 10 PM. SHE/LL REACH NEAR THE SOUTH SANTEE RIVER CLOSER CLOSE TO OR SHORTLY AFTER DAYBREAK. A STRONG PRESSURE GRADIENT AROUND BERYL WILL GENERATE SOUTH AND SW WINDS OF 20-25 KT...WITH GUSTS TO NEAR 30 KT THROUGH MUCH OF THE NIGHT. WHILE WE CANNOT ENTIRELY RULE OUT SOME GUSTS NEAR 35 KT...THEIR INFREQUENCY SUGGESTS THAT WE CAN GET BY WITH A STRONGLY WORDED SCA/S FOR ALL WATERS. SEAS WILL BUILD TO 5-9 FT...TRENDING HIGHER AS YOU NAVIGATE FURTHER FROM SHORE. IN ADDITION...THE VEERING LOW LEVEL WINDS IN THE ATMOSPHERE WILL PRODUCE THE RISK FOR ISOLATED TORNADIC WATERSPOUTS THROUGH THE NIGHT. BASED ON THESE CONDITIONS...MARINERS ARE STRONGLY CAUTIONED ABOUT NAVIGATING WITH EXTREME CARE IF THEY NEED TO BE ON THE COASTAL WATERS. WEDNESDAY THROUGH SUNDAY...TD BERYL IS EXPECTED TO BE POSITIONED JUST INLAND AND VERY CLOSE TO THE CHARLESTON COUNTY WATERS WEDNESDAY MORNING. THE SYSTEM MAY BE IN THE PROCESS OF DEEPENING AT THIS TIME AND A TIGHT PRESSURE GRADIENT WILL BE IN PLACE ACROSS MUCH OF THE WATERS. WINDS WILL BE OUT OF THE NW AND WILL LIKELY BE SUPPORTIVE OF SCA CONDITIONS THROUGH MID/LATE MORNING FOR PORTIONS OF THE AREA. BERYL WILL THEN MOVE STEADILY AWAY THROUGH THE DAY AND WINDS/SEAS WILL IMPROVE. THE PATTERN WILL THEN BECOME QUITE THURSDAY INTO FRIDAY AHEAD OF AN APPROACHING FRONT. THE COLD FRONT IS EXPECTED TO CROSS THE WATERS LATE FRIDAY/EARLY SATURDAY...BUT AT THIS POINT SCA/S ARE NOT LIKELY. && .HYDROLOGY... WE HAVE CANCELLED THE FLASH FLOOD WATCH FOR OUR SE GA COUNTIES...BUT HAVE MAINTAINED THE WATCH FOR SC THROUGH EARLY WEDNESDAY. LATEST TRENDS CONTINUE TO POINT TOWARD LESS COVERAGE OF HEAVY PRECIP THAN PREVIOUSLY EXPECTED. DRIER AIR CONTINUES TO WRAP AROUND TD BERYL FROM THE SW AND SEEMS TO BE LIMITING CONVECTIVE COVERAGE AND INTENSITY. HOWEVER...STRONG LOW LEVEL CONVERGENCE AND FORCING FOR ASCENT WORKING ON PWATS THAT ARE GREATER THAN 2 INCHES WILL SUPPORT THE RISK FOR HEAVY RAINS IN PARTS OF SC. 2-4 INCHES OF RAINFALL ARE EXPECTED...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF MORE PERSISTENT RAIN BANDS DEVELOP AND TRAINING OCCURS. THAT APPEARS MORE LIKELY IF IT WILL HAPPEN OVER THE CHARLESTON TRI- COUNTY AREA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...FLASH FLOOD WATCH UNTIL 6 AM EDT WEDNESDAY FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ330. && $$ |
| #514491 (Received by flhurricane at: 4:44 PM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 432 PM EDT TUE MAY 29 2012 ...HEAVY RAIN ASSOCIATED WITH BERYL IN SOME AREAS OF SOUTH CAROLINA TONIGHT... .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE NORTHEASTWARD ALONG THE SOUTHEAST COASTLINE TONIGHT. BERYL WILL THEN MOVE WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... WE/RE NOT DONE WITH BERYL JUST YET...AS SHE CONTINUES TO MOVE NE AND WILL BE FOUND APPROACHING THE ALTAMAHA RIVER THIS EVENING...THE SAVANNAH RIVER BY MIDNIGHT...THEN APPROACHING OUR NORTHERN ZONES VERY LATE TONIGHT. THIS SYSTEM WILL BRING WITH IT THE RISK OF ISOLATED TORNADOES AND PERIODS OF HEAVY RAINFALL. AS BERYL CONTINUES HER TREK OFF TO THE NE...STRONG LOW LEVEL CONVERGENCE WILL BECOME ENHANCED TONIGHT AS THE CYCLONIC CIRCULATION TRAVERSES THE LOCAL AREA. STRONG UPWARD VERTICAL VELOCITIES ALONG WITH THE RIGHT REAR QUAD OF THE UPPER LEVEL JET PASSING NOT TOO FAR TO THE NW AND STEADY HEIGHT FALLS WILL FURTHER ENHANCE LARGE SCALE ASCENT. WHEN YOU COMBINE THIS WITH PWATS THAT ARE NEAR THE 99TH PERCENTILE FOR LATE MAY WE/RE LOOKING AT SO VERY MUCH NEEDED RAINS. WHILE SE GA WILL GET UP TO ANOTHER 1/2 TO 1 INCH...THE BULK OF THE HEAVIEST RAINS TONIGHT WILL IMPACT SOUTHERN SC WHERE THE BEST CONFLUENCE OFF THE ATLANTIC WILL OCCUR. SEE THE HYDROLOGY SECTION BELOW FOR ADDITIONAL DETAILS. RAIN PROBABILITIES WILL BE NEAR 100 PERCENT OVER ALL OF SOUTHERN SC...AROUND 90 PERCENT NEAR THE SAVANNAH RIVER IN SE GA...TRENDING DOWN TO 60 PERCENT NEAR THE ALTAMAHA RIVER. THE EVENING RUSH HOUR WILL BE WET FOR JUST ABOUT EVERYONE...WHILE THE MOST LIKELY TIMING FOR THE HEAVIEST RAINS IN SC TO OCCUR FROM ABOUT 10 PM TO 4 AM. BY LATE TONIGHT POPS WILL BEGIN DIMINISHING FROM SW TO NE AND BY 6 AM THE STEADIEST RAINS WILL HAVE ENDED FOR SE GA AND FAR SOUTHERN SC. IN REGARDS TO THE POTENTIAL FOR TORNADOES...THERE IS CONSIDERABLE HELICITY WITHIN THE LOW LEVELS OF THE ATMOSPHERE. THAT ALONG WITH VORTICITY GENERATION PARAMETERS APPROACHING 0.2 AND 0-6 KM BULK SHEAR OF 30-35 KT SUGGESTS THAT GIVEN THAT BERYL WILL TRAVEL OVER THE AREA...THERE DOES REMAIN THE RISK OF ISOLATED TORNADOES UNTIL LATE. THE TROPICAL AIR MASS WILL LIMIT TEMPS TONIGHT TO NO LOWER THAN THE UPPER 60S AND LOWER 70S. IT IS WORTH NOTING THAT WINDS WITHIN THE FIRST 2500 FEET ARE AS HIGH AS 35-45 KT. WHILE NOT ALL OF THAT WILL MIX DOWN TONIGHT...WE WILL NEED TO CLOSELY KEEP WATCH FOR A MARGINAL WIND ADVISORY FOR CHARLESTON...COASTAL COLLETON...BEAUFORT AND MAYBE DORCHESTER AND BERKELEY COUNTIES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... WEDNESDAY AND WEDNESDAY NIGHT...BASED ON THE 11AM NHC TRACK FORECAST FOR TD BERYL...ITS CENTER OF CIRCULATION WILL BE POSITIONED JUST OUTSIDE OF THE FORECAST AREA IN THE MORNING. A COLD FRONT WILL APPROACH FROM THE NORTHWEST AND WILL HELP TO DRAW BERYL TO THE NORTHEAST AND AWAY FROM THE AREA. IN THE WAKE OF BERYL AND AS THE WEAK FRONT MOVES IN...MUCH DRIER AIR WILL BEGIN FILTERING INTO SOUTHERN SC AND SOUTHEAST GA. IN FACT WE WILL START THE DAY WITH PWATS NEAR 2 INCHES ACROSS THE TRI-COUNTY AND 1.5 INCHES ELSEWHERE...DECREASING TO LESS THAN 1.25 INCHES EVERYWHERE OVERNIGHT. RAINFALL CHANCES FOR WEDNESDAY WILL PRIMARILY BE ASSOCIATED WITH THE DEPARTURE OF BERYL...AND WE CONTINUE TO HANG ON TO CHANCE TO LIKELY POPS FOR THE FAR NORTHEAST CORNER OF THE FORECAST AREA FOR A COUPLE OF HOURS IN THE MORNING. THEREAFTER...THERE IS SOME POTENTIAL FOR ISOLATED DIURNAL SHOWERS/STORMS ACROSS SOUTHEAST GA. AS CLOUDS CLEAR OUT THROUGH THE DAY AMPLE INSOLATION...DOWNSLOPE FLOW...AND WARM LOW LEVEL THICKNESSES WILL SUPPORT AFTERNOON HIGHS IN THE UPPER 80S TO LOW 90S. THE OVERNIGHT PERIOD WILL BE QUIET WITH LOWS FALLING INTO THE UPPER 60S INLAND AND LOW 70S ALONG THE COAST. THURSDAY THROUGH FRIDAY...THE FORECAST AREA WILL BE UNDER A RATHER NEBULOUS UPPER PATTERN THURSDAY AHEAD OF A VIGOROUS TROF AND UPPER LOW DIGGING INTO THE UPPER MIDWEST. THE FRONT THAT MOVED THROUGH ON WEDNESDAY WILL REMAIN JUST TO THE SOUTH WITH DRY AIR GENERALLY IN PLACE. THE FRONT WILL LIFT BACK TO THE NORTH LATE IN THE DAY AND MAY PROVIDE ENOUGH INCREASE IN MOISTURE TO SUPPORT ISOLATED/SCATTERED SHOWERS/STORMS PRIMARILY ACROSS SOUTHEAST GA. THE MAIN STORY FOR THURSDAY WILL BE THE WARM TEMPERATURES. LOW LEVEL THICKNESSES INCREASE FROM WEDNESDAY AND WILL SUPPORT HIGHS IN THE LOW TO MID 90S PRIOR TO THE SEA BREEZE MOVING THROUGH. THE SEA BREEZE SHOULD BE PRETTY VIGOROUS WITHIN THE DEVELOPING SOUTHERLY FLOW OUT AHEAD OF A COLD FRONT ORGANIZING TO THE WEST. THE STRONG UPPER TROF AND CLOSED LOW WILL MOVE INTO THE GREAT LAKES ON FRIDAY WITH A NORTHERLY UPPER JET ON THE EAST SIDE OF THE TROF AXIS. CURRENT MODEL TIMING FOR THE FRONT CONTINUES TO BE A BIT MIXED...BUT GENERALLY FAVORS BRINGING THE FRONT IN FROM THE WEST LATE FRIDAY NIGHT. INCREASING UPPER SUPPORT AND AFTERNOON HEATING WILL SUPPORT AT LEAST SCATTERED COVERAGE OF SHOWERS/STORMS FRIDAY AFTERNOON/EVENING IN ADVANCE OF THE FRONT. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... MVFR CONDITIONS EXPECTED OVER KSAV AS CONVECTION AND CLOUDS CONTINUE TO MOVE ACROSS THE AREA. WIND GUSTS UP TO 30 KTS POSSIBLE WITH STRONGER SHOWERS. PRECIP CHANCES TAPERING OFF AFTER 03Z AND IMPROVING CIGS BACK TO VFR LATE TONIGHT. FURTHER NORTH FOR KCHS...PRECIP CHANCES WILL INCREASE THROUGH THE AFTERNOON...WITH THE BEST CHANCES BY THIS EVENING. EXPECT MVFR CIGS TO DEVELOP...ESPECIALLY WITHIN SHOWERS. PRECIP CHANCES TAPERING OFF AFTER MIDNIGHT...BUT MVFR CIGS LIKELY TO REMAIN THROUGH SUNRISE TOMORROW. VFR CONDITIONS AFTER 12Z TOMORROW. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL. A COLD FRONT WILL CROSS THE REGION LATE FRIDAY THROUGH EARLY SATURDAY. && .MARINE... TONIGHT...THE MARINE COMMUNITY WILL BE IMPACTED YET AGAIN BY BERYL...AS SHE WILL RETURN ON THE REBOUND...PASSING NE OVER THE NEARBY PORTION OF SC AFTER 9 OR 10 PM. SHE/LL REACH NEAR THE SOUTH SANTEE RIVER CLOSER CLOSE TO OR SHORTLY AFTER DAYBREAK. A STRONG PRESSURE GRADIENT AROUND BERYL WILL GENERATE SOUTH AND SW WINDS OF 20-25 KT...WITH GUSTS TO NEAR 30 KT THROUGH MUCH OF THE NIGHT. WHILE WE CANNOT ENTIRELY RULE OUT SOME GUSTS NEAR 35 KT...THEIR INFREQUENCY SUGGESTS THAT WE CAN GET BY WITH A STRONGLY WORDED SCA/S FOR ALL WATERS. SEAS WILL BUILD TO 5-9 FT...TRENDING HIGHER AS YOU NAVIGATE FURTHER FROM SHORE. IN ADDITION...THE VEERING LOW LEVEL WINDS IN THE ATMOSPHERE WILL PRODUCE THE RISK FOR ISOLATED TORNADIC WATERSPOUTS THROUGH THE NIGHT. BASED ON THESE CONDITIONS...MARINERS ARE STRONGLY CAUTIONED ABOUT NAVIGATING WITH EXTREME CARE IF THEY NEED TO BE ON THE COASTAL WATERS. WEDNESDAY THROUGH SUNDAY...TD BERYL IS EXPECTED TO BE POSITIONED JUST INLAND AND VERY CLOSE TO THE CHARLESTON COUNTY WATERS WEDNESDAY MORNING. THE SYSTEM MAY BE IN THE PROCESS OF DEEPENING AT THIS TIME AND A TIGHT PRESSURE GRADIENT WILL BE IN PLACE ACROSS MUCH OF THE WATERS. WINDS WILL BE OUT OF THE NW AND WILL LIKELY BE SUPPORTIVE OF SCA CONDITIONS THROUGH MID/LATE MORNING FOR PORTIONS OF THE AREA. BERYL WILL THEN MOVE STEADILY AWAY THROUGH THE DAY AND WINDS/SEAS WILL IMPROVE. THE PATTERN WILL THEN BECOME QUITE THURSDAY INTO FRIDAY AHEAD OF AN APPROACHING FRONT. THE COLD FRONT IS EXPECTED TO CROSS THE WATERS LATE FRIDAY/EARLY SATURDAY...BUT AT THIS POINT SCA/S ARE NOT LIKELY. && .HYDROLOGY... WE HAVE CANCELLED THE FLASH FLOOD WATCH FOR OUR SE GA COUNTIES...BUT HAVE MAINTAINED THE WATCH FOR SC THROUGH EARLY WEDNESDAY. LATEST TRENDS CONTINUE TO POINT TOWARD LESS COVERAGE OF HEAVY PRECIP THAN PREVIOUSLY EXPECTED. DRIER AIR CONTINUES TO WRAP AROUND TD BERYL FROM THE SW AND SEEMS TO BE LIMITING CONVECTIVE COVERAGE AND INTENSITY. HOWEVER...STRONG LOW LEVEL CONVERGENCE AND FORCING FOR ASCENT WORKING ON PWATS THAT ARE GREATER THAN 2 INCHES WILL SUPPORT THE RISK FOR HEAVY RAINS IN PARTS OF SC. 2-4 INCHES OF RAINFALL ARE EXPECTED...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF MORE PERSISTENT RAIN BANDS DEVELOP AND TRAINING OCCURS. THAT APPEARS MORE LIKELY IF IT WILL HAPPEN OVER THE CHARLESTON TRI- COUNTY AREA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ330. && $$ |
| #514456 (Received by flhurricane at: 3:06 PM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 242 PM EDT TUE MAY 29 2012 .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE ACROSS NORTHEAST FLORIDA AND SOUTHEAST GEORGIA TODAY AND ACROSS SOUTHEAST SOUTH CAROLINA TONIGHT. THE DEPRESSION WILL MOVE WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HAVE MADE ADJUSTMENTS TO POPS AND TEMPS GIVEN LATEST TRENDS. MORE SCATTERED CLOUD COVER OVER THE NORTHERN 1/3 OF THE REGION HAS ALLOWED TEMPS TO CLIMB INTO THE MID 80S AND HAVE THEREFORE INCREASED MAX TEMPS IN THAT REGION. THINK TEMPS HAVE PRETTY MUCH REACHED THEIR PEAK SINCE THICKER CLOUDS ADVANCING FROM SOUTH TO NORTH TOWARD THE AREA. PRECIP CHANCES HAVE BEEN A BIG CHALLENGE TODAY. LATEST RADAR TRENDS CONTINUE TO INDICATE VERY SCATTERED COVERAGE OVER THE NORTHERN 1/3 OF THE REGION. HAVE LOWERED CURRENT POPS...BUT THEN CONTINUED UPWARD TREND FOR LATER THIS AFTERNOON AND EVENING. HAVE BEEN GETTING SOME GUSTY WINDS OF 30-35 MPH OUT OF STRONGER SHOWERS. INCREASING PRESSURE GRADIENT NORTH AND EAST OF THE TD BERYL HAS RESULTED IN SLIGHTLY STRONGER WINDS OVER THE NORTHERN HALF OF THE REGION THAN PREVIOUSLY FORECAST. THUS...HAVE INCREASED WINDS TO MATCH LATEST TRENDS. BEGINNING TO MORE SERIOUSLY CONSIDER WHETHER OR NOT TO KEEP THE FLASH FLOOD WATCH GOING. DRIER AIR AT MID AND UPPER LEVELS SEEMS TO CONTINUE TO SLOWLY WRAP INTO THE SW SIDE OF THE TD...WHICH MAY BE LIMITING OVERALL PRECIP COVERAGE AND INTENSITY. WFO JAX HAS JUST DROPPED THERE FLOOD WATCH TO OUR SOUTH...AND WILL MAKE A FINAL DECISION FOR LATE AFTERNOON PACKAGE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... WIDESPREAD HEAVY RAINS WILL BE ONGOING BY SUNSET AS TROPICAL DEPRESSION BERYL APPROACHES THE SAVANNAH RIVER. THE CYCLONE WILL MEANDER ACROSS THE LOW COUNTRY OVERNIGHT BEFORE EMERGING OFF THE NORTHEAST COAST OF SOUTH CAROLINA SOMETIME AFTER SUNRISE WEDNESDAY. THE RISK FOR TORRENTIAL RAINFALL WILL PERSIST WITH THE FLASH FLOOD THREAT REMAINING HIGHEST EAST OF INTERSTATE 95. RAIN CHANCES WILL GRADUALLY DIMINISH FROM SOUTHWEST-NORTHEAST AFTER MIDNIGHT AS BERYL APPROACHES THE COAST AND THE AXIS OF DEEPEST TROPICAL MOISTURE SLOWLY SHIFTS OFFSHORE. LOWS WILL RANGE FROM THE UPPER 60S ACROSS INTERIOR SOUTHEAST GEORGIA TO THE LOWER 70S AT THE COAST. WEDNESDAY...BERYL WILL CONTINUE TO EJECT TO THE NORTHEAST AHEAD OF A BROAD UPPER TROUGH APPROACHING FROM THE WEST. SOLID RAIN CHANCES WILL CONTINUE THROUGH THE MORNING HOURS...ESPECIALLY ACROSS NORTHERN SECTIONS OF THE FORECAST AREA CLOSEST TO THE DEPARTING SYSTEM. SHOWER ACTIVITY WILL THEN GENERALLY DIMINISH IN COVERAGE FROM SOUTHWEST TO NORTHEAST AS THE DAY PROGRESSES...WITH DEEP MOISTURE AND CONVERGENCE SHIFTING AWAY FROM THE REGION. HOWEVER...THERE ARE SOME INDICATIONS THAT RESIDUAL LOW/MID LEVEL MOISTURE AND INSTABILITY ACROSS SOUTHEAST GEORGIA COULD SPAWN ISOLATED TO SCATTERED DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS DURING THE LATE AFTERNOON/EARLY EVENING HOURS. DEEP DOWNSLOPE FLOW BEHIND BERYL...COMBINED WITH BETTER INSOLATION UNDER SCATTERING SKY COVER...WILL ALLOW TEMPERATURES TO RISE NOTABLY HIGHER THAN TUESDAY. EXPECT A HIGH TEMPERATURE GRADIENT RANGING FROM THE MID 80S NORTHERN SECTIONS UNDER LINGERING CLOUD COVER...TO AROUND 90 DEGREES SOUTHEAST GEORGIA...WITH LOCALLY COOLER CONDITIONS ALONG THE COASTLINE. HAVE INTRODUCED RAIN FREE CONDITIONS AFTER MIDNIGHT...WITH LOWS IN THE UPPER 60S TO AROUND 70 DEGREES. THURSDAY...A DEEP TROUGH WILL BE MOVING INTO THE MISSISSIPPI VALLEY...SPAWNING A WELL DEFINED SURFACE LOW AND FRONTAL SYSTEM SHIFTING INTO THE OHIO VALLEY LATE IN THE DAY. A WARM FRONTAL FEATURE WILL LIFT NORTHWARD OVER THE FORECAST AREA DOWNSTREAM OF THE SYSTEM...SUPPORTING ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS INTO THE NIGHTTIME HOURS. THE WARMING TREND WILL CONTINUE...WITH DEEP SOUTHERLY FLOW ALLOWING HIGH TEMPERATURES TO PEAK IN THE LOWER 90S. FRIDAY...BOTH 00Z GFS AND ECMWF SHOW THE STRONG UPPER TROUGH BECOMING NEGATIVELY TILTED AS IT SWINGS THROUGH THE OHIO VALLEY AND GREAT LAKES REGION LATE IN THE WEEK. WHILE THE ASSOCIATED SURFACE LOW SHIFTS NORTHEAST WITH THE UPPER LEVEL ENERGY...THE TRAILING COLD FRONT WILL SWEEP EASTWARD TOWARD THE FORECAST AREA. THERE REMAINS SOME TIMING DISCREPANCIES BETWEEN NUMERICAL MODEL SOLUTIONS...HOWEVER GENERAL CONSENSUS SEEMS TO SUGGEST THE FRONT COULD CROSS THE COASTLINE NO EARLIER THAN THE EVENING HOURS. AT THIS POINT...WILL CONTINUE TO ADVERTISE SCATTERED THUNDERSTORMS DURING THE DAYTIME HOURS ON FRIDAY...WHEN DIURNAL INSTABILITY WILL BE MOST ENHANCED AHEAD OF THE APPROACHING FRONTAL SYSTEM. DUE TO TIMING UNCERTAINTIES...PREFER TO CAP POPS FRIDAY AFTERNOON IN THE 30 PERCENT RANGE. STRONG SOUTHERLY FLOW WILL MAINTAIN WARM CONDITIONS ON FRIDAY PEAKING AROUND 90 DEGREES...JUST A DEGREE OR TWO COOLER THAN THURSDAY DUE TO THICKER SKY COVER. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... MVFR CONDITIONS EXPECTED OVER KSAV AS CONVECTION AND CLOUDS CONTINUE TO MOVE ACROSS THE AREA. WIND GUSTS UP TO 30 KTS POSSIBLE WITH STRONGER SHOWERS. PRECIP CHANCES TAPERING OFF AFTER 03Z AND IMPROVING CIGS BACK TO VFR LATE TONIGHT. FURTHER NORTH FOR KCHS...PRECIP CHANCES WILL INCREASE THROUGH THE AFTERNOON...WITH THE BEST CHANCES BY THIS EVENING. EXPECT MVRF CIGS TO DEVELOP...ESPECIALLY WITHIN SHOWERS. PRECIP CHANCES TAPERING OFF AFTER MIDNIGHT...BUT MVFR CIGS LIKELY TO REMAIN THROUGH SUNRISE TOMORROW. VFR CONDITIONS AFTER 12Z TOMORROW. EXTENDED AVIATION OUTLOOK...SUB-VFR CONDITIONS ARE POSSIBLE 12-15Z WEDNESDAY AS TROPICAL DEPRESSION BERYL OR ITS REMNANTS MOVE ACROSS THE REGION. CONDITIONS WILL IMPROVE LATER WEDNESDAY. && .MARINE... HAVE ADJUSTED WINDS UP A TAD TO MATCH LATEST TRENDS...ESPECIALLY OVER THE GA AND SOUTHERN SC WATERS WHERE OBS HAVE SHOWN RECENT GUSTS OF 25 TO 30 KTS. OTHERWISE...PREVIOUS FORECAST KEPT IN TACK. TONIGHT...VERY CHALLENGING WIND FORECAST AS THE EXACT TRACK OF BERYL WILL HAVE A SIGNIFICANT IMPACT ON HOW HIGH WINDS WILL GET. CURRENT NHC/MODEL TRACK KEEPS THE CENTER OF THE DEPRESSION INLAND FROM THE COAST AND KEEPING A GENERAL SOUTHERLY FLOW IN PLACE ACROSS ALL WATERS BEFORE SHIFTING OFFSHORE LATE AS BERYL MOVES OFFSHORE OF THE NORTHEAST SOUTH CAROLINA COAST. THIS TRACK WOULD FAVOR THE HIGHEST WINDS OCCUR OVER THE GEORGIA OFFSHORE LEG WITH SPEEDS 20-25 KT. ACROSS THE NEARSHORE WATERS...15-20 KT LOOKS COMMON WITH SPEEDS DIMINISHING TO 10-15 KT LATE FROM EDISTO BEACH SOUTH TO THE ALTAMAHA RIVER. SEAS WILL BUILD SLIGHTLY OVERNIGHT WITH 6 FT SEAS REACHING THE CHARLESTON COUNTY COASTAL WATERS BY SUNSET. WILL INITIALIZE A SMALL CRAFT ADVISORY FOR THIS ZONE AND CONTINUE IT THROUGH THE OVERNIGHT HOURS CONCURRENT WITH THE OTHER SMALL CRAFT ADVISORIES. WEDNESDAY THROUGH SATURDAY...BERYL WILL STEADILY PROGRESS NORTHEAST AWAY FROM THE MARINE ZONES ON WEDNESDAY...WITH IMPROVING CONDITIONS INTO THE WEEKEND. ANY LINGERING ADVISORIES SHOULD COME TO AN END NO LATER THAN WEDNESDAY AFTERNOON. SOUTHERLY FLOW COULD INCREASE AHEAD OF A COLD FRONT LATE FRIDAY INTO SATURDAY...HOWEVER MARINE CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA AT THIS POINT. RIP CURRENTS...ONGOING SOUTHERLY WINDS COMBINED WITH LINGERING WIND AND SWELL WAVE GENERATED BY BERYL WILL PRODUCE A MODERATE RISK FOR RIP CURRENTS AT AREA BEACHES TODAY. THE RISK WILL BE BORDERLINE HIGH RISK FOR THE GEORGIA BEACHES WERE HIGHER WINDS WILL OCCUR GIVEN THEIR PROXIMITY TO BERYL. HOWEVER OPTED TO KEEP THE RISK MODERATE FOR NOW PER COORDINATION WITH WFO JACKSONVILLE. THE NEED FOR A HIGH RISK WILL BE REEVALUATED LATER TODAY. && .HYDROLOGY... A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH EARLY WEDNESDAY. LATEST TRENDS CONTINUE TO POINT TOWARD LESS COVERAGE OF HEAVY PRECIP THAN PREVIOUSLY EXPECTED. DRIER AIR CONTINUES TO WRAP AROUND TD BERYL FROM THE SW AND SEEMS TO BE LIMITING CONVECTIVE COVERAGE AND INTENSITY. AS MENTIONED ABOVE...WILL MAKE A DECISION FOR THE LATE AFTERNOON PACKAGE AS TO WHETHER OR NOT TO DROP CURRENT FLASH FLOOD WATCH. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ087-088-099>101- 114>119-137>141. SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. && $$ |
| #514421 (Received by flhurricane at: 11:26 AM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1114 AM EDT TUE MAY 29 2012 .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE ACROSS NORTHEAST FLORIDA AND SOUTHEAST GEORGIA TODAY AND ACROSS SOUTHEAST SOUTH CAROLINA TONIGHT. THE DEPRESSION WILL MOVE WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HAVE MADE VERY MINOR CHANGES FOR THE FORECAST THROUGH THE REST OF THE DAY. THE BIGGEST IMMEDIATE CONCERN IS THE POTENTIAL FOR ISOLATED TORNADOES GIVEN THAT THE 12Z CHS SOUNDING INDICATED DECENT LOW LEVEL VEERING. THE BEST INSTABILITY THROUGH THE EARLY AFTERNOON WILL BE OVER OUR SC AREAS...WHICH MAY ALSO BE THE SAME AREA WHERE SOME ISOLATED WEAK TORNADOES WILL BE POSSIBLE IN ANY STRONGER SHOWERS OR THUNDERSTORMS. LATER THIS AFTERNOON...CLOUD CANOPY SHOULD BECOME THICKER WHICH SHOULD HELP TO CUT DOWN ON INSTABILITY. THE OTHER ISSUE IS THE POTENTIAL FOR HEAVY RAINFALL TODAY AND INTO THIS EVENING. LATEST QPF FORECASTS FROM HPC STILL GOING WITH TOTALS OF 2-4 INCHES ACROSS MUCH OF THE AREA...ESPECIALLY EASTERN HALF OF OUR SC ZONES. NOTICED THAT THE LATEST WV IMAGERY INDICATING THAT SOME DRIER AIR IS TRYING TO WORK INTO THE SOUTHERN PERIPHERY OF TD BERYL ACROSS GA. IF THIS TREND CONTINUES CONCERNED IT MAY LEAD TO LOWER QPF VALUES. HAVE NUDGED QPF VALUES DOWN JUST A TAD FOR NOW...BUT CONFIDENCE NOT HIGH ENOUGH YET TO DO ANY SIGNIFICANT LOWERING OF QPF TODAY AND TONIGHT. TEMPERATURES WILL ALSO BE TRICKY TODAY. HAVE CONTINUED TREND OF KEEPING THEM BELOW MOS GUIDANCE GIVEN CLOUD COVER AND HIGH/CATEGORICAL PRECIP CHANCES. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... WIDESPREAD HEAVY RAINS WILL BE ONGOING BY SUNSET AS TROPICAL DEPRESSION BERYL APPROACHES THE SAVANNAH RIVER. THE CYCLONE WILL MEANDER ACROSS THE LOW COUNTRY OVERNIGHT BEFORE EMERGING OFF THE NORTHEAST COAST OF SOUTH CAROLINA SOMETIME AFTER SUNRISE WEDNESDAY. THE RISK FOR TORRENTIAL RAINFALL WILL PERSIST WITH THE FLASH FLOOD THREAT REMAINING HIGHEST EAST OF INTERSTATE 95. RAIN CHANCES WILL GRADUALLY DIMINISH FROM SOUTHWEST-NORTHEAST AFTER MIDNIGHT AS BERYL APPROACHES THE COAST AND THE AXIS OF DEEPEST TROPICAL MOISTURE SLOWLY SHIFTS OFFSHORE. LOWS WILL RANGE FROM THE UPPER 60S ACROSS INTERIOR SOUTHEAST GEORGIA TO THE LOWER 70S AT THE COAST. WEDNESDAY...BERYL WILL CONTINUE TO EJECT TO THE NORTHEAST AHEAD OF A BROAD UPPER TROUGH APPROACHING FROM THE WEST. SOLID RAIN CHANCES WILL CONTINUE THROUGH THE MORNING HOURS...ESPECIALLY ACROSS NORTHERN SECTIONS OF THE FORECAST AREA CLOSEST TO THE DEPARTING SYSTEM. SHOWER ACTIVITY WILL THEN GENERALLY DIMINISH IN COVERAGE FROM SOUTHWEST TO NORTHEAST AS THE DAY PROGRESSES...WITH DEEP MOISTURE AND CONVERGENCE SHIFTING AWAY FROM THE REGION. HOWEVER...THERE ARE SOME INDICATIONS THAT RESIDUAL LOW/MID LEVEL MOISTURE AND INSTABILITY ACROSS SOUTHEAST GEORGIA COULD SPAWN ISOLATED TO SCATTERED DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS DURING THE LATE AFTERNOON/EARLY EVENING HOURS. DEEP DOWNSLOPE FLOW BEHIND BERYL...COMBINED WITH BETTER INSOLATION UNDER SCATTERING SKY COVER...WILL ALLOW TEMPERATURES TO RISE NOTABLY HIGHER THAN TUESDAY. EXPECT A HIGH TEMPERATURE GRADIENT RANGING FROM THE MID 80S NORTHERN SECTIONS UNDER LINGERING CLOUD COVER...TO AROUND 90 DEGREES SOUTHEAST GEORGIA...WITH LOCALLY COOLER CONDITIONS ALONG THE COASTLINE. HAVE INTRODUCED RAIN FREE CONDITIONS AFTER MIDNIGHT...WITH LOWS IN THE UPPER 60S TO AROUND 70 DEGREES. THURSDAY...A DEEP TROUGH WILL BE MOVING INTO THE MISSISSIPPI VALLEY...SPAWNING A WELL DEFINED SURFACE LOW AND FRONTAL SYSTEM SHIFTING INTO THE OHIO VALLEY LATE IN THE DAY. A WARM FRONTAL FEATURE WILL LIFT NORTHWARD OVER THE FORECAST AREA DOWNSTREAM OF THE SYSTEM...SUPPORTING ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS INTO THE NIGHTTIME HOURS. THE WARMING TREND WILL CONTINUE...WITH DEEP SOUTHERLY FLOW ALLOWING HIGH TEMPERATURES TO PEAK IN THE LOWER 90S. FRIDAY...BOTH 00Z GFS AND ECMWF SHOW THE STRONG UPPER TROUGH BECOMING NEGATIVELY TILTED AS IT SWINGS THROUGH THE OHIO VALLEY AND GREAT LAKES REGION LATE IN THE WEEK. WHILE THE ASSOCIATED SURFACE LOW SHIFTS NORTHEAST WITH THE UPPER LEVEL ENERGY...THE TRAILING COLD FRONT WILL SWEEP EASTWARD TOWARD THE FORECAST AREA. THERE REMAINS SOME TIMING DISCREPANCIES BETWEEN NUMERICAL MODEL SOLUTIONS...HOWEVER GENERAL CONSENSUS SEEMS TO SUGGEST THE FRONT COULD CROSS THE COASTLINE NO EARLIER THAN THE EVENING HOURS. AT THIS POINT...WILL CONTINUE TO ADVERTISE SCATTERED THUNDERSTORMS DURING THE DAYTIME HOURS ON FRIDAY...WHEN DIURNAL INSTABILITY WILL BE MOST ENHANCED AHEAD OF THE APPROACHING FRONTAL SYSTEM. DUE TO TIMING UNCERTAINTIES...PREFER TO CAP POPS FRIDAY AFTERNOON IN THE 30 PERCENT RANGE. STRONG SOUTHERLY FLOW WILL MAINTAIN WARM CONDITIONS ON FRIDAY PEAKING AROUND 90 DEGREES...JUST A DEGREE OR TWO COOLER THAN THURSDAY DUE TO THICKER SKY COVER. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... CONDITIONS WILL DETERIORATE AT THE TERMINALS TODAY AS TROPICAL DEPRESSION BERYL DRAWS CLOSER. SHOULD SEES STEADY RAINS FILL IN AT BOTH TERMINALS AS THE DAY PROGRESSES WITH GENERALLY MVFR CIGS/VSBYS OCCURRING. POCKETS OF HEAVY RAIN REDUCING VSBYS TO IFR OR EVEN LIFR WILL BE POSSIBLE AT JUST ABOUT ANY TIME TODAY...BUT THE CHANCES FOR MORE STEADY IFR/LIFR CONDITIONS WILL OCCUR LATE THIS AFTERNOON AT KSAV AND LATE EVENING/OVERNIGHT AT KCHS. EXTENDED AVIATION OUTLOOK...SUB-VFR CONDITIONS ARE POSSIBLE 12-15Z WEDNESDAY AS TROPICAL DEPRESSION BERYL OR ITS REMNANTS MOVE ACROSS THE REGION. CONDITIONS WILL IMPROVE LATER WEDNESDAY. && .MARINE... NO SIGNIFICANT CHANGES MADE FOR FORECAST TODAY. CURRENT SCAS GOING FOR MUCH OF THE REGION EXCEPT AMZ350 AND CHARLESTON HARBOR LOOKS GOOD. HAVE SEEN OBSERVATIONS OF WIND GUSTS AROUND 25 KTS IN THE SHOWERS THAT MOVED ACROSS THE SC WATERS AND INTO THE HARBOR EARLIER...AND EXPECT THIS TO CONTINUE THROUGH THE DAY. STILL EXPECT THE HIGHEST WINDS TO BE ACROSS THE GEORGIA WATERS CLOSEST TO THE CORE OF THE CYCLONE WITH WINDS 20-25 KT WITH 15-20 KT MORE COMMON ACROSS THE SOUTH CAROLINA WATERS INCLUDING THE CHARLESTON HARBOR. SEAS WILL REMAIN IN A FAIRLY STEADY STATE TODAY...RANGING FROM 4-5 FT OFF THE CHARLESTON COUNTY COAST TO 4-7 FT ACROSS THE REMAINING MARINE LEGS. TONIGHT...VERY CHALLENGING WIND FORECAST AS THE EXACT TRACK OF BERYL WILL HAVE A SIGNIFICANT IMPACT ON HOW HIGH WINDS WILL GET. CURRENT NHC/MODEL TRACK KEEPS THE CENTER OF THE DEPRESSION INLAND FROM THE COAST AND KEEPING A GENERAL SOUTHERLY FLOW IN PLACE ACROSS ALL WATERS BEFORE SHIFTING OFFSHORE LATE AS BERYL MOVES OFFSHORE OF THE NORTHEAST SOUTH CAROLINA COAST. THIS TRACK WOULD FAVOR THE HIGHEST WINDS OCCUR OVER THE GEORGIA OFFSHORE LEG WITH SPEEDS 20-25 KT. ACROSS THE NEARSHORE WATERS...15-20 KT LOOKS COMMON WITH SPEEDS DIMINISHING TO 10-15 KT LATE FROM EDISTO BEACH SOUTH TO THE ALTAMAHA RIVER. SEAS WILL BUILD SLIGHTLY OVERNIGHT WITH 6 FT SEAS REACHING THE CHARLESTON COUNTY COASTAL WATERS BY SUNSET. WILL INITIALIZE A SMALL CRAFT ADVISORY FOR THIS ZONE AND CONTINUE IT THROUGH THE OVERNIGHT HOURS CONCURRENT WITH THE OTHER SMALL CRAFT ADVISORIES. WEDNESDAY THROUGH SATURDAY...BERYL WILL STEADILY PROGRESS NORTHEAST AWAY FROM THE MARINE ZONES ON WEDNESDAY...WITH IMPROVING CONDITIONS INTO THE WEEKEND. ANY LINGERING ADVISORIES SHOULD COME TO AN END NO LATER THAN WEDNESDAY AFTERNOON. SOUTHERLY FLOW COULD INCREASE AHEAD OF A COLD FRONT LATE FRIDAY INTO SATURDAY...HOWEVER MARINE CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA AT THIS POINT. RIP CURRENTS...ONGOING SOUTHERLY WINDS COMBINED WITH LINGERING WIND AND SWELL WAVE GENERATED BY BERYL WILL PRODUCE A MODERATE RISK FOR RIP CURRENTS AT AREA BEACHES TODAY. THE RISK WILL BE BORDERLINE HIGH RISK FOR THE GEORGIA BEACHES WERE HIGHER WINDS WILL OCCUR GIVEN THEIR PROXIMITY TO BERYL. HOWEVER OPTED TO KEEP THE RISK MODERATE FOR NOW PER COORDINATION WITH WFO JACKSONVILLE. THE NEED FOR A HIGH RISK WILL BE REEVALUATED LATER TODAY. && .HYDROLOGY... A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH EARLY WEDNESDAY. STILL CONCERNED ABOUT THE POTENTIAL FOR A HEAVY RAIN EVENT ACROSS THE REGION TODAY AS TROPICAL DEPRESSION BERYL TRAVERSES SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. LATEST SATELLITE TRENDS INDICATING THAT SOME DRIER MID AND UPPER LEVEL AIR MAY BE TRYING TO WORK INTO THE SYSTEM FROM THE SOUTH AND WEST. QUESTION IS WHETHER THIS TREND IS INDICATING THE POTENTIAL FOR LOWER QPF AMOUNTS THAN CURRENTLY FORECAST. GIVEN UNCERTAINTY...HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO THE QPF...BUT NOT ANY SIGNIFICANT CHANGES FOR NOW. IN GENERAL...EXPECTING RAINFALL AMOUNTS OF 2-4 INCHES WITH LOCALIZED AMOUNTS OF 5 TO 6 INCHES POSSIBLE. NOTE: THE RISK FOR FLASH FLOODING WILL BECOME ESPECIALLY ENHANCED ACROSS THE COASTAL COUNTIES DURING HIGH TIDE THIS AFTERNOON AND EARLY WEDNESDAY. THIS INCLUDES DOWNTOWN CHARLESTON AND DOWNTOWN SAVANNAH. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ087-088-099>101- 114>119-137>141. SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. && $$ |
| #514382 (Received by flhurricane at: 7:27 AM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 719 AM EDT TUE MAY 29 2012 ...BERYL TO BRING TORRENTIAL RAINFALL TO SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH TONIGHT WITH FLASH FLOODING POSSIBLE... .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE ACROSS NORTHEAST FLORIDA AND SOUTHEAST GEORGIA TODAY AND ACROSS SOUTHEAST SOUTH CAROLINA TONIGHT. THE DEPRESSION WILL MOVE WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... INCREASED QPF ACROSS THE FAR SOUTHERN AREAS FOR THE NEXT FEW HOURS PER CURRENT RADAR TRENDS AND ALSO ADJUSTED TIMING OF CATEGORICAL POPS THROUGH THIS MORNING. NO OTHER CHANGES WERE MADE. TROPICAL DEPRESSION BERYL STILL HAS A WELL DEFINED CIRCULATION EARLY THIS MORNING WITH NUMEROUS FEEDER BANDS ROTATING CYCLONICALLY AROUND THE CENTER OF CIRCULATION. TORRENTIAL RAINS CONTINUE TO FALL NEAR AND TO THE EAST OF THE CENTER WITH KVAX/KJAX SHOWING CORE RAINS PERSISTING ACROSS MUCH OF NORTHEAST FLORIDA. IT APPEARS THE MUCH ANTICIPATED NORTHEAST MOVEMENT HAS BEGUN IN RESPONSE TO THE SLOW REESTABLISHMENT OF WESTERLIES AHEAD OF THE MID- LEVEL TROUGH THAT IS DIGGING ACROSS THE PLAINS STATES. THE STEERING FLOW NEAR AND UPSTREAM OF THE CYCLONE REMAINS FAIRLY LIGHT SO BERYL WILL BE IN NO HURRY TO MOVE OVER THE NEXT 12 HOURS BEFORE IT FINALLY BEGINS TO ACCELERATE OFF THE NORTHEAST AS THE AFOREMENTIONED TROUGH DRAWS CLOSER. MODELS ARE IN GOOD AGREEMENT IN TRACKING THE LOW ACROSS SOUTHEAST THIS AFTERNOON AND EVENING AND OVER SOUTHERN SOUTH CAROLINA TONIGHT...WHICH IS SIMILAR THE LATEST NHC TRACK GUIDANCE. ON THIS TRACK...THE CYCLONE WILL DRAW COPIOUS AMOUNTS OF DEEP-TROPICAL MOISTURE INTO THE REGION WHICH WILL PROMOTE VERY HEAVY RAINS THROUGH TONIGHT. THERE WILL BE A RISK FOR FLASH FLOODING THROUGH EARLY WEDNESDAY GIVEN THE IMPRESSIVE HEAVY RAIN PARAMETERS THAT WILL BE PLACE. SEE THE HYDROLOGY SECTION BELOW FOR MORE INFORMATION ON THE SPECIFIC HEAVY RAIN THREAT. HEAVY RAIN IS EXPECTED TO STEADILY WORK FROM SOUTH-NORTH THIS MORNING WHILE ENCOMPASSING MUCH OF THE FORECAST AREA BY THIS AFTERNOON. CATEGORICAL POPS OF 80-100 PERCENT LOOK APPROPRIATE THROUGH SUNSET ALONG WITH A MENTION OF RAIN BECOMING HEAVY AT TIMES. SOME SURFACE BASED INSTABILITY IS NOTED IN THE VARIOUS MODEL INSTABILITY PROGNOSTICATIONS...BUT THE INCREASINGLY MOIST PROFILES SUGGEST THE RISK FOR TSTMS WILL NOT BE OVERLY HIGH. WILL MAINTAIN A CHANCE OF TSTMS IN THE GRIDDED AND TEXT FORECASTS. EXTENSIVE CLOUD COVER AND THE EXPANDING SHIELD OF RAIN WILL SUPPRESS TEMPERATURES TODAY. HIGHS WILL RANGE FROM AROUND 80 ACROSS THE FAR NORTH WHERE STEADIER RAINS WILL ARRIVE LAST TO THE MID-UPPER 70S ACROSS SOUTHEAST GEORGIA. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... WIDESPREAD HEAVY RAINS WILL BE ONGOING BY SUNSET AS TROPICAL DEPRESSION BERYL APPROACHES THE SAVANNAH RIVER. THE CYCLONE WILL MEANDER ACROSS THE LOWCOUNTRY OVERNIGHT BEFORE EMERGING OFF THE NORTHEAST COAST OF SOUTH CAROLINA SOMETIME AFTER SUNRISE WEDNESDAY. THE RISK FOR TORRENTIAL RAINFALL WILL PERSIST WITH THE FLASH FLOOD THREAT REMAINING HIGHEST EAST OF INTERSTATE 95. RAIN CHANCES WILL GRADUALLY DIMINISH FROM SOUTHWEST-NORTHEAST AFTER MIDNIGHT AS BERYL APPROACHES THE COAST AND THE AXIS OF DEEPEST TROPICAL MOISTURE SLOWLY SHIFTS OFFSHORE. LOWS WILL RANGE FROM THE UPPER 60S ACROSS INTERIOR SOUTHEAST GEORGIA TO THE LOWER 70S AT THE COAST. WEDNESDAY...BERYL WILL CONTINUE TO EJECT TO THE NORTHEAST AHEAD OF A BROAD UPPER TROUGH APPROACHING FROM THE WEST. SOLID RAIN CHANCES WILL CONTINUE THROUGH THE MORNING HOURS...ESPECIALLY ACROSS NORTHERN SECTIONS OF THE FORECAST AREA CLOSEST TO THE DEPARTING SYSTEM. SHOWER ACTIVITY WILL THEN GENERALLY DIMINISH IN COVERAGE FROM SOUTHWEST TO NORTHEAST AS THE DAY PROGRESSES...WITH DEEP MOISTURE AND CONVERGENCE SHIFTING AWAY FROM THE REGION. HOWEVER...THERE ARE SOME INDICATIONS THAT RESIDUAL LOW/MID LEVEL MOISTURE AND INSTABILITY ACROSS SOUTHEAST GEORGIA COULD SPAWN ISOLATED TO SCATTERED DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS DURING THE LATE AFTERNOON/EARLY EVENING HOURS. DEEP DOWNSLOPE FLOW BEHIND BERYL...COMBINED WITH BETTER INSOLATION UNDER SCATTERING SKY COVER...WILL ALLOW TEMPERATURES TO RISE NOTABLY HIGHER THAN TUESDAY. EXPECT A HIGH TEMPERATURE GRADIENT RANGING FROM THE MID 80S NORTHERN SECTIONS UNDER LINGERING CLOUD COVER...TO AROUND 90 DEGREES SOUTHEAST GEORGIA...WITH LOCALLY COOLER CONDITIONS ALONG THE COASTLINE. HAVE INTRODUCED RAIN FREE CONDITIONS AFTER MIDNIGHT...WITH LOWS IN THE UPPER 60S TO AROUND 70 DEGREES. THURSDAY...A DEEP TROUGH WILL BE MOVING INTO THE MISSISSIPPI VALLEY...SPAWNING A WELL DEFINED SURFACE LOW AND FRONTAL SYSTEM SHIFTING INTO THE OHIO VALLEY LATE IN THE DAY. A WARM FRONTAL FEATURE WILL LIFT NORTHWARD OVER THE FORECAST AREA DOWNSTREAM OF THE SYSTEM...SUPPORTING ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS INTO THE NIGHTTIME HOURS. THE WARMING TREND WILL CONTINUE...WITH DEEP SOUTHERLY FLOW ALLOWING HIGH TEMPERATURES TO PEAK IN THE LOWER 90S. FRIDAY...BOTH 00Z GFS AND ECMWF SHOW THE STRONG UPPER TROUGH BECOMING NEGATIVELY TILTED AS IT SWINGS THROUGH THE OHIO VALLEY AND GREAT LAKES REGION LATE IN THE WEEK. WHILE THE ASSOCIATED SURFACE LOW SHIFTS NORTHEAST WITH THE UPPER LEVEL ENERGY...THE TRAILING COLD FRONT WILL SWEEP EASTWARD TOWARD THE FORECAST AREA. THERE REMAINS SOME TIMING DISCREPANCIES BETWEEN NUMERICAL MODEL SOLUTIONS...HOWEVER GENERAL CONSENSUS SEEMS TO SUGGEST THE FRONT COULD CROSS THE COASTLINE NO EARLIER THAN THE EVENING HOURS. AT THIS POINT...WILL CONTINUE TO ADVERTISE SCATTERED THUNDERSTORMS DURING THE DAYTIME HOURS ON FRIDAY...WHEN DIURNAL INSTABILITY WILL BE MOST ENHANCED AHEAD OF THE APPROACHING FRONTAL SYSTEM. DUE TO TIMING UNCERTAINTIES...PREFER TO CAP POPS FRIDAY AFTERNOON IN THE 30 PERCENT RANGE. STRONG SOUTHERLY FLOW WILL MAINTAIN WARM CONDITIONS ON FRIDAY PEAKING AROUND 90 DEGREES...JUST A DEGREE OR TWO COOLER THAN THURSDAY DUE TO THICKER SKY COVER. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... CONDITIONS WILL DETERIORATE AT THE TERMINALS TODAY AS TROPICAL DEPRESSION BERYL DRAWS CLOSER. SHOULD SEES STEADY RAINS FILL IN AT BOTH TERMINALS AS THE DAY PROGRESSES WITH GENERALLY MVFR CIGS/VSBYS OCCURRING. POCKETS OF HEAVY RAIN REDUCING VSBYS TO IFR OR EVEN LIFR WILL BE POSSIBLE AT JUST ABOUT ANY TIME TODAY...BUT THE CHANCES FOR MORE STEADY IFR/LIFR CONDITIONS WILL OCCUR LATE THIS AFTERNOON AT KSAV AND LATE EVENING/OVERNIGHT AT KCHS. EXTENDED AVIATION OUTLOOK...SUB-VFR CONDITIONS ARE POSSIBLE 12-15Z WEDNESDAY AS TROPICAL DEPRESSION BERYL OR ITS REMNANTS MOVE ACROSS THE REGION. CONDITIONS WILL IMPROVE LATER WEDNESDAY. && .MARINE... TODAY...SOUTHEAST WINDS WILL VEER TO THE SOUTH TODAY AS TROPICAL DEPRESSION BERYL MEANDERS OFF TO THE NORTHEAST. THE HIGHEST WINDS WILL BE FOUND ACROSS THE GEORGIA WATERS CLOSEST TO THE CORE OF THE CYCLONE WITH WINDS 20-25 KT WITH 15-20 KT MORE COMMON ACROSS THE SOUTH CAROLINA WATERS INCLUDING THE CHARLESTON HARBOR. SEAS WILL REMAIN IN A FAIRLY STEADY STATE TODAY...RANGING FROM 4-5 FT OFF THE CHARLESTON COUNTY COAST TO 4-7 FT ACROSS THE REMAINING MARINE LEGS. THE GOING SMALL CRAFT ADVISORY WILL BE EXPANDED NORTH TO INCLUDE THE WATERS OFF BEAUFORT COUNTY SEAS SEAS WILL TONIGHT...VERY CHALLENGING WIND FORECAST AS THE EXACT TRACK OF BERYL WILL HAVE A SIGNIFICANT IMPACT ON HOW HIGH WINDS WILL GET. CURRENT NHC/MODEL TRACK KEEPS THE CENTER OF THE DEPRESSION INLAND FROM THE COAST AND KEEPING A GENERAL SOUTHERLY FLOW IN PLACE ACROSS ALL WATERS BEFORE SHIFTING OFFSHORE LATE AS BERYL MOVES OFFSHORE OF THE NORTHEAST SOUTH CAROLINA COAST. THIS TRACK WOULD FAVOR THE HIGHEST WINDS OCCUR OVER THE GEORGIA OFFSHORE LEG WITH SPEEDS 20-25 KT. ACROSS THE NEARSHORE WATERS...15-20 KT LOOKS COMMON WITH SPEEDS DIMINISHING TO 10-15 KT LATE FROM EDISTO BEACH SOUTH TO THE ALTAMAHA RIVER. SEAS WILL BUILD SLIGHTLY OVERNIGHT WITH 6 FT SEAS REACHING THE CHARLESTON COUNTY COASTAL WATERS BY SUNSET. WILL INITIALIZE A SMALL CRAFT ADVISORY FOR THIS ZONE AND CONTINUE IT THROUGH THE OVERNIGHT HOURS CONCURRENT WITH THE OTHER SMALL CRAFT ADVISORIES. WEDNESDAY THROUGH SATURDAY...BERYL WILL STEADILY PROGRESS NORTHEAST AWAY FROM THE MARINE ZONES ON WEDNESDAY...WITH IMPROVING CONDITIONS INTO THE WEEKEND. ANY LINGERING ADVISORIES SHOULD COME TO AN END NO LATER THAN WEDNESDAY AFTERNOON. SOUTHERLY FLOW COULD INCREASE AHEAD OF A COLD FRONT LATE FRIDAY INTO SATURDAY...HOWEVER MARINE CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA AT THIS POINT. RIP CURRENTS...ONGOING SOUTHERLY WINDS COMBINED WITH LINGERING WIND AND SWELL WAVE GENERATED BY BERYL WILL PRODUCE A MODERATE RISK FOR RIP CURRENTS AT AREA BEACHES TODAY. THE RISK WILL BE BORDERLINE HIGH RISK FOR THE GEORGIA BEACHES WERE HIGHER WINDS WILL OCCUR GIVEN THEIR PROXIMITY TO BERYL. HOWEVER OPTED TO KEEP THE RISK MODERATE FOR NOW PER COORDINATION WITH WFO JACKSONVILLE. THE NEED FOR A HIGH RISK WILL BE REEVALUATED LATER TODAY. && .HYDROLOGY... A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH EARLY WEDNESDAY. AN IMPRESSIVE AND POTENTIALLY DANGEROUS HEAVY RAIN EVENT WILL UNFOLD ACROSS THE REGION TODAY AS TROPICAL DEPRESSION BERYL TRAVERSES SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. MODELS ARE SIMILAR IN TAKING THE CYCLONE ALONG OR JUST INLAND FROM THE COAST WITH AN AXIS OF VERY TROPICAL AIR FEATURING PWATS AROUND 2.40 INCHES BECOMING SITUATED ACROSS THE ENTIRE REGION THROUGH TONIGHT. PWATS OF THIS MAGNITUDE ARE EXTREMELY RARE FOR LATE MAY AND RANK ROUGHLY IN THE 99TH PERCENTILE PER KCHS RAOB CLIMATOLOGY. NEAR RECORD PWATS COUPLED WITH SOME UPPER LEVEL DIVERGENCE SUGGEST RAINFALL RATES COULD EXCEED 3-4 IN/HR IN THE BANDS OF MOST INTENSE RAIN. ALTHOUGH DROUGHT CONDITIONS PERSIST...THE INTENSITY OF THESE RAINFALL RATES COULD EASILY EXCEED 1-HOUR AND 3-HOUR FLASH FLOOD GUIDANCE. A FLASH FLOOD WATCH IS IN EFFECT GIVEN THESE PARAMETERS. RAIN RATES COULD GO EVEN HIGHER OVERNIGHT AS CORE RAINS TRY AND REDEVELOP NEAR THE CENTER. THE RISK FOR FLASH FLOODING WILL BECOME ESPECIALLY ENHANCED ACROSS THE COASTAL COUNTIES DURING HIGH TIDE THIS AFTERNOON AND EARLY WEDNESDAY. THIS INCLUDES DOWNTOWN CHARLESTON AND DOWNTOWN SAVANNAH. GENERAL RAINFALL AMOUNTS WILL RANGE FROM 3-5 INCHES WITH LOCALIZED AMOUNTS EXCEEDING 7 INCHES. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ087-088-099>101- 114>119-137>141. SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. && $$ |
| #514350 (Received by flhurricane at: 4:26 AM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 418 AM EDT TUE MAY 29 2012 ...BERYL TO BRING TORRENTIAL RAINFALL TO SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH TONIGHT WITH FLASH FLOODING POSSIBLE... .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL MOVE ACROSS NORTHEAST FLORIDA AND SOUTHEAST GEORGIA TODAY AND ACROSS SOUTHEAST SOUTH CAROLINA TONIGHT. THE DEPRESSION WILL MOVE WELL OFFSHORE WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TROPICAL DEPRESSION BERYL STILL HAS A WELL DEFINED CIRCULATION EARLY THIS MORNING WITH NUMEROUS FEEDER BANDS ROTATING CYCLONICALLY AROUND THE CENTER OF CIRCULATION. TORRENTIAL RAINS CONTINUE TO FALL NEAR AND TO THE EAST OF THE CENTER WITH KVAX/KJAX SHOWING CORE RAINS PERSISTING ACROSS MUCH OF NORTHEAST FLORIDA. IT APPEARS THE MUCH ANTICIPATED NORTHEAST MOVEMENT HAS BEGUN IN RESPONSE TO THE SLOW REESTABLISHMENT OF WESTERLIES AHEAD OF THE MID- LEVEL TROUGH THAT IS DIGGING ACROSS THE PLAINS STATES. THE STEERING FLOW NEAR AND UPSTREAM OF THE CYCLONE REMAINS FAIRLY LIGHT SO BERYL WILL BE IN NO HURRY TO MOVE OVER THE NEXT 12 HOURS BEFORE IT FINALLY BEGINS TO ACCELERATE OFF THE NORTHEAST AS THE AFOREMENTIONED TROUGH DRAWS CLOSER. MODELS ARE IN GOOD AGREEMENT IN TRACKING THE LOW ACROSS SOUTHEAST THIS AFTERNOON AND EVENING AND OVER SOUTHERN SOUTH CAROLINA TONIGHT...WHICH IS SIMILAR THE LATEST NHC TRACK GUIDANCE. ON THIS TRACK...THE CYCLONE WILL DRAW COPIOUS AMOUNTS OF DEEP-TROPICAL MOISTURE INTO THE REGION WHICH WILL PROMOTE VERY HEAVY RAINS THROUGH TONIGHT. THERE WILL BE A RISK FOR FLASH FLOODING THROUGH EARLY WEDNESDAY GIVEN THE IMPRESSIVE HEAVY RAIN PARAMETERS THAT WILL BE PLACE. SEE THE HYDROLOGY SECTION BELOW FOR MORE INFORMATION ON THE SPECIFIC HEAVY RAIN THREAT. HEAVY RAIN IS EXPECTED TO STEADILY WORK FROM SOUTH-NORTH THIS MORNING WHILE ENCOMPASSING MUCH OF THE FORECAST AREA BY THIS AFTERNOON. CATEGORICAL POPS OF 80-100 PERCENT LOOK APPROPRIATE THROUGH SUNSET ALONG WITH A MENTION OF RAIN BECOMING HEAVY AT TIMES. SOME SURFACE BASED INSTABILITY IS NOTED IN THE VARIOUS MODEL INSTABILITY PROGNOSTICATIONS...BUT THE INCREASINGLY MOIST PROFILES SUGGEST THE RISK FOR TSTMS WILL NOT BE OVERLY HIGH. WILL MAINTAIN A CHANCE OF TSTMS IN THE GRIDDED AND TEXT FORECASTS. EXTENSIVE CLOUD COVER AND THE EXPANDING SHIELD OF RAIN WILL SUPPRESS TEMPERATURES TODAY. HIGHS WILL RANGE FROM AROUND 80 ACROSS THE FAR NORTH WHERE STEADIER RAINS WILL ARRIVE LAST TO THE MID-UPPER 70S ACROSS SOUTHEAST GEORGIA. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... WIDESPREAD HEAVY RAINS WILL BE ONGOING BY SUNSET AS TROPICAL DEPRESSION BERYL APPROACHES THE SAVANNAH RIVER. THE CYCLONE WILL MEANDER ACROSS THE LOWCOUNTRY OVERNIGHT BEFORE EMERGING OFF THE NORTHEAST COAST OF SOUTH CAROLINA SOMETIME AFTER SUNRISE WEDNESDAY. THE RISK FOR TORRENTIAL RAINFALL WILL PERSIST WITH THE FLASH FLOOD THREAT REMAINING HIGHEST EAST OF INTERSTATE 95. RAIN CHANCES WILL GRADUALLY DIMINISH FROM SOUTHWEST-NORTHEAST AFTER MIDNIGHT AS BERYL APPROACHES THE COAST AND THE AXIS OF DEEPEST TROPICAL MOISTURE SLOWLY SHIFTS OFFSHORE. LOWS WILL RANGE FROM THE UPPER 60S ACROSS INTERIOR SOUTHEAST GEORGIA TO THE LOWER 70S AT THE COAST. WEDNESDAY...BERYL WILL CONTINUE TO EJECT TO THE NORTHEAST AHEAD OF A BROAD UPPER TROUGH APPROACHING FROM THE WEST. SOLID RAIN CHANCES WILL CONTINUE THROUGH THE MORNING HOURS...ESPECIALLY ACROSS NORTHERN SECTIONS OF THE FORECAST AREA CLOSEST TO THE DEPARTING SYSTEM. SHOWER ACTIVITY WILL THEN GENERALLY DIMINISH IN COVERAGE FROM SOUTHWEST TO NORTHEAST AS THE DAY PROGRESSES...WITH DEEP MOISTURE AND CONVERGENCE SHIFTING AWAY FROM THE REGION. HOWEVER...THERE ARE SOME INDICATIONS THAT RESIDUAL LOW/MID LEVEL MOISTURE AND INSTABILITY ACROSS SOUTHEAST GEORGIA COULD SPAWN ISOLATED TO SCATTERED DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS DURING THE LATE AFTERNOON/EARLY EVENING HOURS. DEEP DOWNSLOPE FLOW BEHIND BERYL...COMBINED WITH BETTER INSOLATION UNDER SCATTERING SKY COVER...WILL ALLOW TEMPERATURES TO RISE NOTABLY HIGHER THAN TUESDAY. EXPECT A HIGH TEMPERATURE GRADIENT RANGING FROM THE MID 80S NORTHERN SECTIONS UNDER LINGERING CLOUD COVER...TO AROUND 90 DEGREES SOUTHEAST GEORGIA...WITH LOCALLY COOLER CONDITIONS ALONG THE COASTLINE. HAVE INTRODUCED RAIN FREE CONDITIONS AFTER MIDNIGHT...WITH LOWS IN THE UPPER 60S TO AROUND 70 DEGREES. THURSDAY...A DEEP TROUGH WILL BE MOVING INTO THE MISSISSIPPI VALLEY...SPAWNING A WELL DEFINED SURFACE LOW AND FRONTAL SYSTEM SHIFTING INTO THE OHIO VALLEY LATE IN THE DAY. A WARM FRONTAL FEATURE WILL LIFT NORTHWARD OVER THE FORECAST AREA DOWNSTREAM OF THE SYSTEM...SUPPORTING ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS INTO THE NIGHTTIME HOURS. THE WARMING TREND WILL CONTINUE...WITH DEEP SOUTHERLY FLOW ALLOWING HIGH TEMPERATURES TO PEAK IN THE LOWER 90S. FRIDAY...BOTH 00Z GFS AND ECMWF SHOW THE STRONG UPPER TROUGH BECOMING NEGATIVELY TILTED AS IT SWINGS THROUGH THE OHIO VALLEY AND GREAT LAKES REGION LATE IN THE WEEK. WHILE THE ASSOCIATED SURFACE LOW SHIFTS NORTHEAST WITH THE UPPER LEVEL ENERGY...THE TRAILING COLD FRONT WILL SWEEP EASTWARD TOWARD THE FORECAST AREA. THERE REMAINS SOME TIMING DISCREPANCIES BETWEEN NUMERICAL MODEL SOLUTIONS...HOWEVER GENERAL CONSENSUS SEEMS TO SUGGEST THE FRONT COULD CROSS THE COASTLINE NO EARLIER THAN THE EVENING HOURS. AT THIS POINT...WILL CONTINUE TO ADVERTISE SCATTERED THUNDERSTORMS DURING THE DAYTIME HOURS ON FRIDAY...WHEN DIURNAL INSTABILITY WILL BE MOST ENHANCED AHEAD OF THE APPROACHING FRONTAL SYSTEM. DUE TO TIMING UNCERTAINTIES...PREFER TO CAP POPS FRIDAY AFTERNOON IN THE 30 PERCENT RANGE. STRONG SOUTHERLY FLOW WILL MAINTAIN WARM CONDITIONS ON FRIDAY PEAKING AROUND 90 DEGREES...JUST A DEGREE OR TWO COOLER THAN THURSDAY DUE TO THICKER SKY COVER. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... WILL CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE EAST COAST LATE FRIDAY INTO EARLY SATURDAY. TIMING DIFFERENCES BETWEEN MODEL SOLUTIONS ADD SOME UNCERTAINTY...AND PREFER TO REMAIN RATHER CONSERVATIVE WITH POPS IN THE 20 TO 30 PERCENT RANGE FRIDAY NIGHT. HAVE THEN INDICATED SHOWER/THUNDERSTORM ACTIVITY DIMINISHING FROM WEST TO EAST BEHIND THE DEPARTING FRONT SATURDAY...WITH POPS BELOW 15 PERCENT BY SATURDAY NIGHT. SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL BUILD INTO THE AREA EARLY NEXT WEEK...AND HAVE MAINTAINED DRY WEATHER ACCORDINGLY. LATEST MODEL TRENDS SUGGEST THAT ANY COOLING TREND BEHIND THE COLD FRONT SATURDAY WILL BE SUBTLE AT BEST...SO WILL MAINTAIN HIGH TEMPERATURES IN THE UPPER 80S TO LOWER 90S THROUGH THE EXTENDED PERIOD. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... OVERNIGHT...RAINS FROM THE TROPICAL DEPRESSION IN A DEEP MOIST AIR MASS WILL CONTINUE TO PERIODICALLY SPIRAL ONSHORE AND TIMING THESE SHOWERS WILL REMAIN QUITE DIFFICULT OUTSIDE OF THE INITIAL SEVERAL HOURS OF THIS TAF CYCLE UNTIL STEADIER RAINS DEVELOP LATER TODAY. MVFR CIGS SHOULD ALSO BE PERIODIC OVERNIGHT AND PROBABLY MORE WIDESPREAD LATE TONIGHT WHEN SPEED CONVERGENCE IN THE LOWEST LAYERS BECOMES MAXIMIZED. RAIN CHANCES WILL BE ON THE INCREASE AT KSAV THIS MORNING AND EVEN AT KCHS LATER TODAY AS THE TROPICAL DEPRESSION TURNS BACK UP THE SE U.S. COAST. PERIODIC CIGS/VSBYS IN MVFR RANGE WITH SOME IFR VSBYS IN HEAVY RAINS POSSIBLE. THE HEAVIER RAINS ARE POSSIBLE IN SAVANNAH THIS AFTERNOON AND EVENING AND AT KCHS DURING THE LATTER 6 HOURS OF THE 06Z CYCLE TAF PERIOD. EXTENDED AVIATION OUTLOOK...SUB-VFR CONDITIONS ARE POSSIBLE 06Z TO 15Z WEDNESDAY...AS TROPICAL DEPRESSION BERYL OR ITS REMNANTS MOVE ACROSS THE REGION. CONDITIONS WILL IMPROVE LATER WEDNESDAY. && .MARINE... TODAY...SOUTHEAST WINDS WILL VEER TO THE SOUTH TODAY AS TROPICAL DEPRESSION BERYL MEANDERS OFF TO THE NORTHEAST. THE HIGHEST WINDS WILL BE FOUND ACROSS THE GEORGIA WATERS CLOSEST TO THE CORE OF THE CYCLONE WITH WINDS 20-25 KT WITH 15-20 KT MORE COMMON ACROSS THE SOUTH CAROLINA WATERS INCLUDING THE CHARLESTON HARBOR. SEAS WILL REMAIN IN A FAIRLY STEADY STATE TODAY...RANGING FROM 4-5 FT OFF THE CHARLESTON COUNTY COAST TO 4-7 FT ACROSS THE REMAINING MARINE LEGS. THE GOING SMALL CRAFT ADVISORY WILL BE EXPANDED NORTH TO INCLUDE THE WATERS OFF BEAUFORT COUNTY SEAS SEAS WILL TONIGHT...VERY CHALLENGING WIND FORECAST AS THE EXACT TRACK OF BERYL WILL HAVE A SIGNIFICANT IMPACT ON HOW HIGH WINDS WILL GET. CURRENT NHC/MODEL TRACK KEEPS THE CENTER OF THE DEPRESSION INLAND FROM THE COAST AND KEEPING A GENERAL SOUTHERLY FLOW IN PLACE ACROSS ALL WATERS BEFORE SHIFTING OFFSHORE LATE AS BERYL MOVES OFFSHORE OF THE NORTHEAST SOUTH CAROLINA COAST. THIS TRACK WOULD FAVOR THE HIGHEST WINDS OCCUR OVER THE GEORGIA OFFSHORE LEG WITH SPEEDS 20-25 KT. ACROSS THE NEARSHORE WATERS...15-20 KT LOOKS COMMON WITH SPEEDS DIMINISHING TO 10-15 KT LATE FROM EDISTO BEACH SOUTH TO THE ALTAMAHA RIVER. SEAS WILL BUILD SLIGHTLY OVERNIGHT WITH 6 FT SEAS REACHING THE CHARLESTON COUNTY COASTAL WATERS BY SUNSET. WILL INITIALIZE A SMALL CRAFT ADVISORY FOR THIS ZONE AND CONTINUE IT THROUGH THE OVERNIGHT HOURS CONCURRENT WITH THE OTHER SMALL CRAFT ADVISORIES. WEDNESDAY THROUGH SATURDAY...BERYL WILL STEADILY PROGRESS NORTHEAST AWAY FROM THE MARINE ZONES ON WEDNESDAY...WITH IMPROVING CONDITIONS INTO THE WEEKEND. ANY LINGERING ADVISORIES SHOULD COME TO AN END NO LATER THAN WEDNESDAY AFTERNOON. SOUTHERLY FLOW COULD INCREASE AHEAD OF A COLD FRONT LATE FRIDAY INTO SATURDAY...HOWEVER MARINE CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA AT THIS POINT. RIP CURRENTS...ONGOING SOUTHERLY WINDS COMBINED WITH LINGERING WIND AND SWELL WAVE GENERATED BY BERYL WILL PRODUCE A MODERATE RISK FOR RIP CURRENTS AT AREA BEACHES TODAY. THE RISK WILL BE BORDERLINE HIGH RISK FOR THE GEORGIA BEACHES WERE HIGHER WINDS WILL OCCUR GIVEN THEIR PROXIMITY TO BERYL. HOWEVER OPTED TO KEEP THE RISK MODERATE FOR NOW PER COORDINATION WITH WFO JACKSONVILLE. THE NEED FOR A HIGH RISK WILL BE REEVALUATED LATER TODAY. && .HYDROLOGY... A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THROUGH EARLY WEDNESDAY. AN IMPRESSIVE AND POTENTIALLY DANGEROUS HEAVY RAIN EVENT WILL UNFOLD ACROSS THE REGION TODAY AS TROPICAL DEPRESSION BERYL TRAVERSES SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. MODELS ARE SIMILAR IN TAKING THE CYCLONE ALONG OR JUST INLAND FROM THE COAST WITH AN AXIS OF VERY TROPICAL AIR FEATURING PWATS AROUND 2.40 INCHES BECOMING SITUATED ACROSS THE ENTIRE REGION THROUGH TONIGHT. PWATS OF THIS MAGNITUDE ARE EXTREMELY RARE FOR LATE MAY AND RANK ROUGHLY IN THE 99TH PERCENTILE PER KCHS RAOB CLIMATOLOGY. NEAR RECORD PWATS COUPLED WITH SOME UPPER LEVEL DIVERGENCE SUGGEST RAINFALL RATES COULD EXCEED 3-4 IN/HR IN THE BANDS OF MOST INTENSE RAIN. ALTHOUGH DROUGHT CONDITIONS PERSIST...THE INTENSITY OF THESE RAINFALL RATES COULD EASILY EXCEED 1-HOUR AND 3-HOUR FLASH FLOOD GUIDANCE. A FLASH FLOOD WATCH IS IN EFFECT GIVEN THESE PARAMETERS. RAIN RATES COULD GO EVEN HIGHER OVERNIGHT AS CORE RAINS TRY AND REDEVELOP NEAR THE CENTER. THE RISK FOR FLASH FLOODING WILL BECOME ESPECIALLY ENHANCED ACROSS THE COASTAL COUNTIES DURING HIGH TIDE THIS AFTERNOON AND EARLY WEDNESDAY. THIS INCLUDES DOWNTOWN CHARLESTON AND DOWNTOWN SAVANNAH. GENERAL RAINFALL AMOUNTS WILL RANGE FROM 3-5 INCHES WITH LOCALIZED AMOUNTS EXCEEDING 7 INCHES. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ087-088-099>101- 114>119-137>141. SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ040-042>045- 047>052. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR AMZ352-354. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT WEDNESDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR AMZ374. && $$ |
| #514310 (Received by flhurricane at: 2:00 AM 29.May.2012) AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 147 AM EDT TUE MAY 29 2012 .SYNOPSIS... TROPICAL DEPRESSION BERYL WILL STALL ACROSS SOUTHERN GEORGIA AND NORTHERN FLORIDA TONIGHT BEFORE TURNING BACK TO THE NE AND MOVING UP THE SOUTHEAST COAST THROUGH THE MIDDLE OF THE WEEK. A COLD FRONT APPROACHING FROM THE WEST COULD IMPACT THE AREA FOR THE LATE WEEK PERIOD...WITH HIGH PRESSURE FOLLOWING IN ITS WAKE THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THIS EVENING...REGIONAL RADAR IMAGERY AND SURFACE OBSERVATIONS INDICATE THAT TROPICAL DEPRESSION BERYL WAS VERY CLOSE TO VALDOSTA GEORGIA...POSSIBLY A FEW MILES TO THE W. 00Z SOUNDING/UPPER AIR ANALYSIS SHOWED JUICY 15-17C 850 MB DEW POINTS ANCHORED OVER S CENTRAL GEORGIA S TO THE REGION BETWEEN JACKSONVILLE AND TALLAHASSEE FLORIDA. AT 500 MB...A 580 MB LOW SIT ATOP THE DEPRESSION WARM -7C TEMPS NOTED. SURFACE HIGH PRES OVER THE MID ATLC REGION WAS PRODUCING A WEAK WEDGE SURFACE PATTERN OVER N GEORGIA AND UPSTATE SOUTH CAROLINA. BERYL IS FORECAST TO BEGIN A MORE NW TURN OVERNIGHT BEFORE SHIFTING A LITTLE MORE N BEFORE DAYBREAK. A LITTLE EARLIER THIS EVENING WE NOTED AN ISOLATED SHOWER OVER JENKINS COUNTY GEORGIA PRODUCE WEAK ROTATION USING A STORM RELATIVE MOTION OF 122 DEGREES AT 18 KT. SPC MESOANALYSIS SUGGEST POTENTIAL FOR VERY WEAK MINI-SUPERCELL STRUCTURES TONIGHT BUT OVERALL THE CURRENT SYNOPTIC SITUATION AND SHEAR IS NOT TOO IMPRESSIVE TO GET OVERLY CONCERNED ABOUT AT THIS TIME. NOT MUCH CHANGED ON EVENING UPDATES...WE LOWERED INITIAL POPS IN SOME GEORGIA ZONES AS THE PCPN WAS STUBBORN WORK N OF THE ALTAMAHA. SHOWERS SPIRALING IN OFF THE SOUTH CAROLINA KEEPING DECENT CHANCES OF SHOWERS IN THE CHARLESTON TRI-COUNTY AREA OVERNIGHT. THE BULK OF THE MORE SIGNIFICANT RAINS WAITING UNTIL TUE-TUE NIGHT. HIGH PWATS AND A DEEP TROPICAL AIR MASS SUGGEST SHOWERS WILL PRODUCE DOWNPOURS BUT VERY LITTLE LIGHTNING. ONLY MINOR COSMETIC CHANGES TO TEMPS/WINDS OVERNIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... TUESDAY AND TUESDAY NIGHT...THE FORECAST WILL BE DOMINATED BY WHAT IS CURRENTLY CLASSIFIED AS TROPICAL DEPRESSION BERYL. FORECAST MODELS OUTSIDE OF THE NAM ARE IN EXCELLENT AGREEMENT REGARDING THE TRACK OF THE SYSTEM...TAKING IT TO THE NORTHEAST CLOSELY HUGGING THE GA/SC COASTLINE. THIS WILL TAKE BERYL AND IT/S DEEP TROPICAL MOISTURE RIGHT ACROSS THE HEART OF THE FORECAST AREA. PWATS ARE PROGGED TO START THE DAY JUST BELOW 2 INCHES...INCREASING TO THE 2-2.25 INCH RANGE BY LATE TUESDAY NIGHT AS THE SYSTEM IS DRAWN NORTHEASTWARD BY A TROF CROSSING THE GREAT LAKES THAT BREAKS DOWN THE RIDGE TO THE NORTH. PWATS THIS HIGH WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MAY. I HAVE INCREASED POPS INTO THE CATEGORICAL RANGE EVERYWHERE AT SOME POINT TUESDAY AND TUESDAY NIGHT. RIGHT NOW IT APPEARS THE HEAVIEST RAINS WILL MOVE ACROSS THE AREA BEGINNING TUESDAY AFTERNOON THROUGH THE EARLY MORNING HOURS ON WEDNESDAY. PLEASE REFER TO THE HYDROLOGY SECTION BELOW FOR MORE DETAILS CONCERNING THE EXPECTED WIDESPREAD HEAVY RAINFALL. WEDNESDAY THROUGH THURSDAY...PRECIP ASSOCIATED WITH BERYL WILL COME TO AN END WEDNESDAY MORNING AS THE SYSTEM MOVES FURTHER NORTHEAST AND ALONG THE NC COASTLINE. A COLD FRONT WILL MOVE IN FROM THE NORTHWEST THROUGH THE DAY ON WEDNESDAY WITH MUCH DRIER DEEP LAYER AIR IN THE WAKE OF BERYL. IN FACT...PWATS ARE EXPECTED TO FALL BACK BELOW 1.5 INCHES BY WEDNESDAY NIGHT ESPECIALLY ACROSS SOUTHERN SC. WILL START THE DAY WITH CHANCE POPS ACROSS THE NORTHEAST CORNER OF THE FORECAST AREA...DECREASING THEREAFTER. THERE MAY BE ENOUGH LINGERING MOISTURE ACROSS SE GA TO SUPPORT SCATTERED CONVECTION WEDNESDAY AFTERNOON WHERE BETTER SURFACE HEATING WILL OCCUR. BY THURSDAY...A DEEP TROF WILL BEGIN TO DIG INTO THE CENTRAL PLAINS WITH A SHORTWAVE RIDGE DOWNSTREAM. EXPECT ISOLATED TO SCATTERED CONVECTION PRIMARILY FORCED BY DIURNAL HEATING. LOW LEVEL THICKNESSES LOOK TO BE QUITE WARM EACH DAY WITH UPPER 80S TO LOW 90S EXPECTED IN MOST AREAS EACH AFTERNOON. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... MEDIUM RANGE MODELS CONTINUE TO INDICATE A STRONG COLD FRONT CROSSING THE FORECAST AREA LATE FRIDAY INTO EARLY SATURDAY...BEFORE SURFACE HIGH PRESSURE BUILDS IN ITS WAKE THROUGH EARLY NEXT WEEK. WILL MAINTAIN SOLID SHOWER/THUNDERSTORM CHANCES ON FRIDAY...WITH PRECIPITATION POTENTIAL DIMINISHING BEHIND THE FRONT SATURDAY. WILL THEN KEEP THE FORECAST DRY SATURDAY NIGHT THROUGH MONDAY AT THIS POINT...AS HIGH PRESSURE SETTLES OVER THE REGION. WILL INDICATE SLIGHTLY COOLER HIGH TEMPERATURES SATURDAY INTO EARLY NEXT WEEK...RANGING GENERALLY IN THE LOW TO MID 80S. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... OVERNIGHT...RAINS FROM THE TROPICAL DEPRESSION IN A DEEP MOIST AIR MASS WILL CONTINUE TO PERIODICALLY SPIRAL ONSHORE AND TIMING THESE SHOWERS WILL REMAIN QUITE DIFFICULT OUTSIDE OF THE INITIAL SEVERAL HOURS OF THIS TAF CYCLE UNTIL STEADIER RAINS DEVELOP LATER TODAY. MVFR CIGS SHOULD ALSO BE PERIODIC OVERNIGHT AND PROBABLY MORE WIDESPREAD LATE TONIGHT WHEN SPEED CONVERGENCE IN THE LOWEST LAYERS BECOMES MAXIMIZED. RAIN CHANCES WILL BE ON THE INCREASE AT KSAV THIS MORNING AND EVEN AT KCHS LATER TODAY AS THE TROPICAL DEPRESSION TURNS BACK UP THE SE U.S. COAST. PERIODIC CIGS/VSBYS IN MVFR RANGE WITH SOME IFR VSBYS IN HEAVY RAINS POSSIBLE. THE HEAVIER RAINS ARE POSSIBLE IN SAVANNAH THIS AFTERNOON AND EVENING AND AT KCHS DURING THE LATTER 6 HOURS OF THE 06Z CYCLE TAF PERIOD. EXTENDED AVIATION OUTLOOK...SUB-VFR CONDITIONS ARE 06Z-15Z WED AS AS TROPICAL DEPRESSION BERYL OR ITS REMNANTS MOVE ACROSS THE REGION. VERY HEAVY RAIN IS POSSIBLE AT KCHS BETWEEN 04Z-10Z TUE AS THE SYSTEM BEGINS TO GAIN STRENGTH AND MOMENTUM. CONDITIONS WILL IMPROVE THROUGH THE DAY ON WED. && .MARINE... THERE REMAINS A LARGE PRESSURE DIFFERENCE BETWEEN BERYL AND A LARGE AREA OF WESTERN ATLANTIC HIGH PRES AND A WEAK WEDGE TO OUR N. THIS WILL KEEP WINDS AND SEAS HIGH ENOUGH WHERE WE HAVE SMALL CRAFT ADVISORIES CONTINUING FOR ALL BUT CHARLESTON HARBOR WHERE WINDS WILL BE IN THE 15-20 KT RANGE. CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE NIGHT...AND BY 6 AM TUESDAY THE ONLY ONGOING SCA/S WILL BE ACROSS OUR GA WATERS OUT 60 NM. WHILE WE HAVEN/T SEEN MUCH IN THE WAY OF ROTATING CELLS OVER THE ATLANTIC TODAY...GIVEN A DECENT AMOUNT OF SHEAR IN THE ATMOSPHERE THERE IS STILL THE LOW-END PROBABILITY OF AN ISOLATED WATERSPOUT. TUESDAY AND TUESDAY NIGHT...BERYL WILL MOVE NORTHEASTWARD RIGHT ALONG THE GA/SC COASTLINE. THOUGH THE SYSTEM IS LIKELY TO BE A TROPICAL DEPRESSION OR THE REMNANTS OF...THE TIGHT PRESSURE GRADIENT AROUND ITS CIRCULATION AND LINGERING SWELL ENERGY WILL RESULT IN DETERIORATING CONDITIONS ACROSS THE LOCAL WATERS. WINDS WILL LIKELY BE CLOSE TO SCA CRITERIA WITH SEAS BUILDING THROUGH THE NIGHT. SCA/S WILL LIKELY BE NEEDED FOR ALL OF THE MARINE AREAS AT SOME POINT THROUGH TUESDAY NIGHT. I HAVE EXTENDED THE CURRENT SCA FOR ALL OF THE GA WATERS INTO TUESDAY NIGHT...AS THESE AREAS ARE LEAST LIKELY TO COME DOWN BELOW CRITERIA. THE SC WATERS ARE EXPECTED TO EXPERIENCE A LULL PERIOD IN WIND/SEAS BEFORE RAMPING BACK UP TUESDAY AFTERNOON AS THE CENTER OF CIRCULATION GETS CLOSER. WEDNESDAY ONWARD...BERYL WILL STEADILY PROGRESS NORTHEAST AWAY FROM THE MARINE ZONES ON WEDNESDAY...WITH IMPROVING CONDITIONS INTO THE WEEKEND. ANY LINGERING ADVISORIES SHOULD COME DOWN EARLY WEDNESDAY. RIP CURRENTS...THERE IS A LITTLE LESS WIND AND SWELL FOR TUE...AS A RESULT THE RIP CURRENT RISK WILL BE IN THE MODERATE RANGE FOR ALL BEACHES ON TUE. && .HYDROLOGY... THERE HAS BEEN A LULL IN THE RAINFALL WHERE WE HAVE THE FLASH FLOOD WATCH IN EFFECT...BUT THAT WILL BEGIN TO CHANGE AGAIN TONIGHT INTO TUESDAY. STRONG LOW LEVEL CONVERGENCE AND ABUNDANT MOISTURE WITH PWATS NEAR 2 STANDARD DEVIATIONS ABOVE NORMAL WILL ALLOW FOR RAIN BANDS WILL ONCE AGAIN DEVELOP AND SWING THROUGH SE GA AND SOUTHERN SC. THESE BANDS WILL DUMP UP TO AN INCH OR MORE IN A SHORT PERIOD OF TIME...AND IF ONE OR MORE PERSISTENT BANDS DEVELOP...THEN LOCALIZED AMOUNTS COULD BE EVEN MORE. DEEP TROPICAL MOISTURE ASSOCIATED WITH BERYL WILL STEADILY MOVE INTO THE REGION TUESDAY AND TUESDAY NIGHT. WIDESPREAD MODERATE...TO AT TIMES HEAVY...RAINFALL WILL FALL ACROSS THE REGION PRIMARILY TUESDAY AFTERNOON THROUGH VERY EARLY WEDNESDAY. VERY HIGH PRECIPITABLE WATER VALUES WILL RESULT IN VERY EFFICIENT RAINFALL PRODUCTION ACROSS MUCH OF THE AREA. FOR NOW OUR STORM TOTAL RAINFALL AMOUNTS WILL AVERAGE 3-6 INCHES SOUTH OF I-16...HIGHEST ALONG THE COAST...TO 1-3 INCHES ELSEWHERE. WE HAVE OPTED NOT TO ALTER THE CURRENT CONFIGURATION OF THE FLASH FLOOD WATCH AS MODERATE TO HEAVY RAINFALL HAS ONLY AFFECTED ISOLATED LOCATIONS THUS FAR. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR GAZ114>119- 137>141. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR AMZ354. SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR AMZ374. && $$ |
