AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 619 PM EDT FRI JUL 8 2011 .SYNOPSIS... DEEPER MOISTURE WILL GRADUALLY INCREASE OVER THE REGION THROUGH TONIGHT AS WEAK LOW PRESSURE ALONG THE GULF COAST PERSISTS. A WEAK FRONT WILL MOVE INTO THE AREA LATE IN THE WEEKEND BEFORE DISSIPATING. BERMUDA RIDGE WILL DOMINATE THE WEATHER ACROSS THE AREA EARLY NEXT WEEK. ANOTHER FRONT WILL APPROACH FROM THE NORTH BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MADE MINOR ADJUSTMENTS TO WEATHER...POPS AND TEMPERATURES FOR THE NEXT SEVERAL HOURS TO TAKE CURRENT TRENDS INTO ACCOUNT. DESPITE ALL OF THE CLOUD COVER TODAY...SAVANNAH MANAGED TO EEK OUT ANOTHER 90+ DEGREE DAY BRINGING THE TOTAL TO 50. AREA OBSERVATIONS HAVE SHOWN HAZE AND SMOKE ACROSS MUCH OF INTERIOR SOUTHEAST GEORGIA FOR MUCH OF THE DAY. FIRE OFFICIALS ARE STILL REPORTING ISSUES WITH SMOKE. WILL HOLD OFF ON ISSUING ANY STATEMENTS OR INCLUDING SMOKE IN THE GRIDDED/TEXT FORECASTS UNTIL WE CAN RUN A HYSPLIT MODEL LATER THIS EVENING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... UPPER TROUGH ALONG THE EAST COAST AT START OF THE PERIOD WILL LIFT NORTHEAST AT START OF THE PERIOD. BERMUDA RIDGE AND LARGE RIDGE ACROSS THE SOUTHERN PLAINS WILL COMBINE...WITH A LARGE RIDGE OF HIGH PRESSURE COVERING THE SOUTHERN TWO-THIRDS OF THE NATION DURING THE LATER HALF OF THE WEEKEND AND THROUGH EARLY NEXT WEEK. A WEAK FRONTAL BOUNDARY AT THE SURFACE WILL STRUGGLE TO PUSH SOUTHWARD AS UPPER TROUGH LIFTS OUT. AT THIS TIME...WILL BRING DIFFUSE FRONT INTO FORECAST AREA SUN MORNING AND THEN DISSIPATE IT THROUGH THE DAY. PRECIPITABLE WATER VALUES ON SAT WILL STILL BE VERY HIGH AND ON THE ORDER OF TWO AND A THIRD INCHES. ALTHOUGH SIGNIFICANT CLOUD COVER IS EXPECTED...THERE WILL BE ENOUGH HEATING TO INCREASE CAPE VALUES ABOVE 2000 J/KG. DEEP MOISTURE WILL REMAIN IN PLACE...ESPECIALLY ALONG THE COAST. WILL CARRY LIKELY POPS DURING SAT. DUE TO THE HIGH MOISTURE CONTENT...ANY CONVECTION WILL HAVE THE CAPABILITY FOR HEAVY DOWNPOURS. DEWPOINTS IN THE MID TO PERHAPS UPPER 70S WILL COMBINE WITH TEMPS IN THE LOWER 90S TO PRODUCE HEAT INDICES ABOVE 100 DEG...BUT MOST LOCATIONS SHOULD REMAIN JUST BELOW HEAT ADVISORY CRITERIA. SUNDAY SHOULD BE A TRANSITION DAY AS COLUMN BEGINS TO DRY OUT FROM THE TOP DOWN. WEAK FRONT WILL BE IN THE PROCESS OF DISSOLVING AND SINCE SUBSIDENCE WILL NOT HAVE A FIRM GRIP ON THE AREA...WILL DROP POPS AS CONVECTION SHOULD BE MORE SCATTERED WITH THE HIGHEST POPS ON SUN EXPECTED ALONG AND INLAND FROM THE SEABREEZE. BUILDING RIDGE AND INFLUX OF DRIER AIR WILL YIELD MORE HEAT THAN ON SAT. MAXIMUMS MAINLY IN THE MID 90S WILL COMBINE WITH HIGH DEWPOINTS TO PUSH THE HEAT INDEX TO NEAR ADVISORY CRITERIA...ESPECIALLY AWAY FROM THE IMMEDIATE COAST. MUCH DRIER AIR SHOULD BE IN PLACE ON MON WITH PRECIPITABLE WATER VALUES DROPPING TO LESS THAN ONE AND A HALF INCHES. SUBSIDENCE WILL BE STRONGER ON MON THAN OVER THE WEEKEND. AS CAPPING INVERSION ERODES WITH STRONG HEATING THROUGH THE AFTERNOON...WILL CARRY SLIGHT CHANCE TO LOW CHANCE FOR AFTERNOON AND EARLY EVE SHOWERS AND THUNDERSTORMS...WITH SLIGHTLY HIGHER POPS INLAND AND ALONG THE SEABREEZE. MONDAY WILL LIKELY BE THE MOST UNCOMFORTABLE DAY OF THE PERIOD. HIGHS IN THE MID 90S TO UPPER 90S INLAND WILL RESULT IN HEAT INDICES ABOVE 105 DEGREES ACROSS MOST OF THE AREA. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... TUESDAY LOOKS QUITE SIMILAR TO MONDAY AS WIDELY SCATTERED AFTERNOON AND EVENING CONVECTION IS EXPECTED...BUT LOTS OF SUNSHINE WILL ALLOW TEMPS TO RISE WELL INTO THE 90S AWAY FROM THE COAST WITH HEAT INDICES INTO THE MID 100S. THE SECOND HALF OF THE WEEK IS MORE COMPLICATED. GFS HAS SHIFTED SIGNIFICANTLY FROM ITS SOLUTION 24 HOURS. NOW..INSTEAD OF HOLDING UP THE NEXT COLD FRONT NORTH OF THE AREA...IT PLOWS IT THROUGH MID WEEK AND BRINGS IN A SIGNIFICANTLY DRIER AIR MASS FOR THURSDAY AND FRIDAY. I HAVE ONLY NUDGED THE FORECAST SLIGHTLY IN THAT DIRECTION DUE TO THE LACK OF CONTINUITY...PLUS THE FACT THAT YESTERDAYS ECMWF HAS BACKED OF ITS FRONTAL PASSAGE BY A DAY. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... KCHS...CONVECTION CONTINUING ATTM AS TROPICAL MOISTURE STREAMS OVER A COASTAL TROUGH. ALTHOUGH SHOWERS ARE BECOMING MORE SCATTERED IN NATURE...STILL A GOOD CHANCE THAT CHS WILL SEE TEMPO MVFR CIGS FOR THE FIRST FEW HOURS. AFTER THAT HAVE CARRIED JUST CB DUE TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWERS. GUIDANCE HINTING AT SOME LOW STRATUS TONIGHT AND WITH COLUMN BECOMING LESS SATURATED WE MAY CLEAR ENOUGH FOR THIS TO COME TO FRUITION. AT THE SAME TIME...SIGNIFICANT ELEVATED INSTABILITY COMBINED WITH A PASSING SHORTWAVE MAY RE-INITIATE CONVECTION BEFORE DAYBREAK WHICH WOULD LIMIT STRATUS POTENTIAL. NO FOG THREAT DUE TO ENHANCED WINDS OVERNIGHT. MORE CONVECTION IS EXPECTED ON SATURDAY. KSAV...LIMITED CONVECTION ACROSS THE AREA WILL LIKELY FILL IN AS SIGNALED BY BOTH HIGH RES GUIDANCE AND LATEST RUC FORECAST SOUNDINGS. NOT ENOUGH CONFIDENCE TO MENTION ANYTHING BUT CB IN TAF...BUT KSAV MAY SEE SOME CONVECTION THAT WILL REQUIRE AMD/S LATER THIS AFTN. LOW LEVEL STRATUS IS A CONCERN HERE AS WELL OVERNIGHT...BUT WILL BE IMPACTED CONSIDERABLY BY HOW MUCH CLOUD COVER/CONVECTION CAN DEVELOP OVERNIGHT. ANOTHER DAY OF WIDESPREAD SHOWERS/TSTMS EXPECTED SATURDAY. EXTENDED AVIATION OUTLOOK...AS IS USUALLY THE CASE IN MID SUMMER...THE BEST CHANCE FOR MVFR/IFR CIGS/VSBYS IS WITH THE CHANCES OF AFTERNOON AND EVENING CONVECTION NEAR THE TERMINALS. ALSO...WITH WINDS EXPECTED TO GET VERY LIGHT ON MONDAY AND TUESDAY MORNINGS...THERE COULD BE A COUPLE OF HOURS OF BR AROUND SUNRISE EACH DAY. && .MARINE... PINCHED GRADIENT BETWEEN BERMUDA HIGH AND WEAK LOW PRESSURE DROPPING INTO THE SOUTHEAST WILL SUPPORT WINDS OF 15 TO 20 KT. IN ADDITION STRONG LOW LEVEL JET...BETWEEN 20 AND 25 KT...WILL RESULT IN GUSTY WINDS. CONDITIONS ACROSS NEAR SHORE ZONES WILL REMAIN BELOW SCA THRESHOLDS...BUT OFFSHORE GEORGIA ZONES ARE LIKELY TO SEE SLIGHTLY HIGHER WINDS AND SEAS. WITHIN 20 NM MILES SEAS WILL RUN 3 TO 5 FT...WHILE FARTHER OFFSHORE 4 TO 6 FT...WITH OCCASIONAL 7 FT. RIP CURRENTS...SE SWELLS WILL CONTRIBUTE TO AN ENHANCED RISK FOR RIP CURRENTS FOR ALL OF OUR BEACHES. WINDS WILL BE FROM THE SW SAT AND SAT EVE AND STRONGEST WINDS ARE EXPECTED THROUGH SAT MORNING. HOWEVER...AS NOCTURNAL JET DISSIPATES...SW WINDS ACROSS THE WATERS WILL BE DIMINISHING. WILL CONTINUE SCA FOR OUTER GEORGIA WATERS THROUGH ABOUT MIDDAY ON SAT FOR LINGERING 6 FT SEAS AND WIND GUSTS TO 25 KT. ELSEWHERE...WILL CAP WINDS AT 15 KT WITH GUSTS TO 20 KT AND SEAS AT 3 TO 5 FT. SW WINDS WILL CONTINUE TO SLOWLY DIMINISH SAT NIGHT AND BY SUN MORNING SHOULD BE LESS THAN 10 KT THROUGHOUT. THE WIND DIRECTION MAY BECOME LIGHT AND VARIABLE FOR A TIME...ESPECIALLY ACROSS THE NORTHERN WATERS DUE TO THE PROXIMITY OF A WEAK FRONT ON SUN. GRADIENT WILL BE PRETTY SLACK MONDAY THROUGH WEDNESDAY WITH LIGHT WINDS GENERALLY OUT OF THE SOUTH AND SOUTHWEST...TURNING ONSHORE NEAR THE COAST IN THE AFTERNOON AND EVENING. WINDS MAY PICK UP SOME AGAIN ON WEDNESDAY AHEAD OF THE NEXT FRONT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR AMZ374. && $$