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Show Area Forecast Discussion - San Juan, PR (Puerto Rico) Selection: |
| #535743 (Received by flhurricane at: 10:54 PM 20.Aug.2012) AFDSJU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 1049 PM AST MON AUG 20 2012 .UPDATE...SHOWERS AND THUNDERSTORMS DISSIPATED ACROSS SOUTHWESTERN PUERTO RICO LATE IN THE AFTERNOON. AFTER THE SHOWER ACTIVITY ENDED...ONLY ISOLATED SHOWERS REMAINED OVER THE AREA WATERS. NO CHANGES WERE MADE TO THE FORECAST PACKAGE AS IT HAD A GOOD HANDLE ON THE CURRENT AND EXPECTED CONDITIONS. INVEST 94L HAS NOW A 90 PERCENT OF BECOMING A TROPICAL CYCLONE IN THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED ESPECIALLY FOR WEDNESDAY AND THURSDAY ACROSS THE FORECAST AREA. && .AVIATION...LOUDINESS AND SHOWERS WILL INCREASE OVERNIGHT AND EARLY IN THE MORNING ACROSS THE U.S. VIRGIN ISLANDS AND EASTERN SECTIONS OF PUERTO RICO. THIS MOISTURE WILL INDUCE BRIEF PERIODS OF MVFR CONDITIONS ACROSS TNCM...TKPK...TIST AND TISX. ELSEWHERE ACROSS THE REST OF THE LOCAL FLYING AREA MOSTLY VFR CONDITIONS ARE EXPECTED. && .PREV DISCUSSION... /ISSUED 340 PM AST MON AUG 20 2012/ SYNOPSIS...A BROAD HIGH PRESSURE CENTERED TO THE NORTH-NORTHEAST OF THE LOCAL ISLANDS...WILL CONTINUE TO PRODUCE MODERATE TRADES ACROSS THE AREA AS WELL AS FAIR WEATHER CONDITIONS THROUGH AT LEAST TUESDAY MORNING. AN ACTIVE WEATHER PATTERN IS EXPECTED FROM TUESDAY NIGHT THROUGH AT LEAST FRIDAY AS A SERIES OF TROPICAL DISTURBANCE/WAVES WILL MOVE ACROSS THE LOCAL REGION. DISCUSSION...STRONG DAYTIME HEATING COMBINED WITH AVAILABLE MOISTURE AND SEA BREEZE CONVERGENCE TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND STRONG THUNDERSTORMS ACROSS THE SOUTHWEST QUADRANT OF PUERTO RICO. FOR TUESDAY AFTERNOON THROUGH LATE TUESDAY NIGHT...A TROPICAL WAVE AND ITS ASSOCIATED MOISTURE WILL MOVE JUST SOUTH OF THE FORECAST AREA. ALTHOUGH...THE BULK OF THE MOISTURE IS EXPECTED TO PASS SOUTH OF THE LOCAL AREA...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS PARTS OF THE LOCAL ISLANDS...ESPECIALLY ACROSS THE WEST AND SOUTH SECTIONS OF PUERTO RICO. WE ARE MONITORING A VIGOROUS TROPICAL WAVE LOCATED ABOUT 1000 MILES EAST THE LESSER ANTILLES. SATELLITE IMAGERY AND BUOY OBSERVATIONS INDICATE THAT THE CIRCULATION HAS BECOME BETTER DEFINED OVER THE PAST FEW HOURS. HOWEVER...SHOWER AND THUNDERSTORM ACTIVITY REMAINS LIMITED. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT BEFORE CROSS THE LESSER ANTILLES. MOST OF THE OPERATIONAL MODELS AGREE THAT THIS DISTURBANCE WILL APPROACH THE LOCAL REGION BETWEEN WEDNESDAY AFTERNOON AND EARLY THURSDAY MORNING. REGARDLESS OF DEVELOPMENT...ALL MODEL GUIDANCE CONTINUE TO SUGGEST DEEP CONVECTION WITH INCREASING WINDS...SQUALLY CONDITIONS AND HAZARDOUS SEAS...BEGINNING ON WEDNESDAY AND CONTINUING THROUGH THURSDAY AND POSSIBLY INTO FRIDAY. THEREFORE THE POTENTIAL FOR SIGNIFICANT FLASH FLOODING WITH PERIODS OF HEAVY RAINFALL AND GUSTY WINDS WILL BE VERY HIGH BEGINNING ON WEDNESDAY THROUGH FRIDAY. AVIATION...VFR CONDS FCST THROUGH THE FORECAST PERIOD...EXCEPT FOR PERIODS OF AFTN CONVECTION OVR THE WEST INTERIOR AND VCNTY OF TJMZ AND TJPS THROUGH 20/22Z. MARINE...MARINE CONDITIONS ARE EXPECTED TO DETERIORATE BEGINNING TUESDAY AFTERNOON AND BECOMING HAZARDOUS EARLY WEDNESDAY. THE SEAS WILL INCREASE UP TO 11 FEET IN EXPOSED AREAS THROUGH THURSDAY. MARINERS SHOULD SEEK FURTHER DETAILS IN THE COASTAL WATERS FORECAST AND THE MARINE WEATHER MESSAGE. CONDITIONS WILL IMPROVE OVER THE FOLLOWING WEEKEND BUT SEAS ARE EXPECTED TO INCREASE AGAIN FROM THE EAST EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... SJU 79 92 78 90 / 30 30 30 60 STT 81 90 80 92 / 20 30 40 70 && .SJU WATCHES/WARNINGS/ADVISORIES... PR... VI...NONE. COASTAL WATERS...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 6 AM AST FRIDAY FOR ANEGADA PASSAGE SOUTHWARD TO 17N. SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO NOON AST FRIDAY FOR CARIBBEAN WATERS OF PUERTO RICO FROM 10 NM TO 17N. SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 PM AST FRIDAY FOR ATLC WATERS OF PUERTO RICO AND USVI FROM 10NM TO 19.5N. && $$ |
| #535679 (Received by flhurricane at: 3:42 PM 20.Aug.2012) AFDSJU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 340 PM AST MON AUG 20 2012 .SYNOPSIS...A BROAD HIGH PRESSURE CENTERED TO THE NORTH-NORTHEAST OF THE LOCAL ISLANDS...WILL CONTINUE TO PRODUCE MODERATE TRADES ACROSS THE AREA AS WELL AS FAIR WEATHER CONDITIONS THROUGH AT LEAST TUESDAY MORNING. AN ACTIVE WEATHER PATTERN IS EXPECTED FROM TUESDAY NIGHT THROUGH AT LEAST FRIDAY AS A SERIES OF TROPICAL DISTURBANCE/WAVES WILL MOVE ACROSS THE LOCAL REGION. && .DISCUSSION...STRONG DAYTIME HEATING COMBINED WITH AVAILABLE MOISTURE AND SEA BREEZE CONVERGENCE TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND STRONG THUNDERSTORMS ACROSS THE SOUTHWEST QUADRANT OF PUERTO RICO. FOR TUESDAY AFTERNOON THROUGH LATE TUESDAY NIGHT...A TROPICAL WAVE AND ITS ASSOCIATED MOISTURE WILL MOVE JUST SOUTH OF THE FORECAST AREA. ALTHOUGH...THE BULK OF THE MOISTURE IS EXPECTED TO PASS SOUTH OF THE LOCAL AREA...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS PARTS OF THE LOCAL ISLANDS...ESPECIALLY ACROSS THE WEST AND SOUTH SECTIONS OF PUERTO RICO. WE ARE MONITORING A VIGOROUS TROPICAL WAVE LOCATED ABOUT 1000 MILES EAST THE LESSER ANTILLES. SATELLITE IMAGERY AND BUOY OBSERVATIONS INDICATE THAT THE CIRCULATION HAS BECOME BETTER DEFINED OVER THE PAST FEW HOURS. HOWEVER...SHOWER AND THUNDERSTORM ACTIVITY REMAINS LIMITED. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT BEFORE CROSS THE LESSER ANTILLES. MOST OF THE OPERATIONAL MODELS AGREE THAT THIS DISTURBANCE WILL APPROACH THE LOCAL REGION BETWEEN WEDNESDAY AFTERNOON AND EARLY THURSDAY MORNING. REGARDLESS OF DEVELOPMENT...ALL MODEL GUIDANCE CONTINUE TO SUGGEST DEEP CONVECTION WITH INCREASING WINDS...SQUALLY CONDITIONS AND HAZARDOUS SEAS...BEGINNING ON WEDNESDAY AND CONTINUING THROUGH THURSDAY AND POSSIBLY INTO FRIDAY. THEREFORE THE POTENTIAL FOR SIGNIFICANT FLASH FLOODING WITH PERIODS OF HEAVY RAINFALL AND GUSTY WINDS WILL BE VERY HIGH BEGINNING ON WEDNESDAY THROUGH FRIDAY. && .AVIATION...VFR CONDS FCST THROUGH THE FORECAST PERIOD...EXCEPT FOR PERIODS OF AFTN CONVECTION OVR THE WEST INTERIOR AND VCNTY OF TJMZ AND TJPS THROUGH 20/22Z. && .MARINE...MARINE CONDITIONS ARE EXPECTED TO DETERIORATE BEGINNING TUESDAY AFTERNOON AND BECOMING HAZARDOUS EARLY WEDNESDAY. THE SEAS WILL INCREASE UP TO 11 FEET IN EXPOSED AREAS THROUGH THURSDAY. MARINERS SHOULD SEEK FURTHER DETAILS IN THE COASTAL WATERS FORECAST AND THE MARINE WEATHER MESSAGE. CONDITIONS WILL IMPROVE OVER THE FOLLOWING WEEKEND BUT SEAS ARE EXPECTED TO INCREASE AGAIN FROM THE EAST EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... SJU 79 92 78 90 / 30 30 30 60 STT 81 90 80 92 / 20 30 40 70 && .SJU WATCHES/WARNINGS/ADVISORIES... PR... VI...NONE. COASTAL WATERS...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 6 AM AST FRIDAY FOR ANEGADA PASSAGE SOUTHWARD TO 17N. SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO NOON AST FRIDAY FOR CARIBBEAN WATERS OF PUERTO RICO FROM 10 NM TO 17N. SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 PM AST FRIDAY FOR ATLC WATERS OF PUERTO RICO AND USVI FROM 10NM TO 19.5N. && $$ |
| #535639 (Received by flhurricane at: 12:33 PM 20.Aug.2012) AFDSJU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 1226 PM AST MON AUG 20 2012 .UPDATE...TUTT AND ASSOCIATED LOW EXTENDS FROM THE WEST CENTRAL CARIBBEAN SOUTHWEST INTO THE NORTHEAST CARIBBEAN...WITH UPPER HIGH CENTERED ACROSS THE TROPICAL ATLANTIC...EXTENDING WEST AND SOUTHWEST OVER THE LESSER ANTILLES. A TROPICAL WAVE JUST EAST OF THE LESSER ANTILLES IS EXPECTED TO MOVE ACROSS THE WINDWARD ISLANDS LATE TONIGHT THROUGH TUESDAY MORNING AND MOVE MAINLY SOUTH OF THE REGION ON TUESDAY. A STRONG AND ACTIVE TROPICAL WAVE AND ASSOCIATED AREA OF LOW PRESSURE WITH AXIS NOW NEAR 43 WEST...CONTINUED TO MOVE QUICKLY WESTWARD TOWARDS THE ISLANDS CHAIN. BASED ON LATEST GUIDANCE FROM THE NATIONAL HURRICANE CENTER IN MIAMI...THIS FEATURE HAS A HIGH PROBABILITY OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS OR SO...LOCAL INTERESTS SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. REGARDLESS OF WHETHER THIS SYSTEM BECOMES A TROPICAL CYCLONE OR NOT...ALL MODEL GUIDANCE CONTINUE TO SUGGEST DEEP CONVECTION WITH INCREASING WINDS...SQUALLY CONDITIONS AND HAZARDOUS SEAS...BEGINNING ON WEDNESDAY AND CONTINUING THROUGH THURSDAY AND POSSIBLY INTO FRIDAY. THEREFORE THE POTENTIAL FOR SIGNIFICANT FLASH FLOODING WITH PERIODS OF HEAVY RAINFALL AND GUSTY WINDS WILL BE VERY HIGH BEGINNING ON WEDNESDAY AND CONTINUING THROUGH THE END OF THE WORK WEEK. && .AVIATION UPDATE...NO CHANGE TO PREVIOUS AVIATION DISCUSSION.VFR CONDS FCST FOR NEXT 24 HRS EXCEPT FOR PERIODS OF AFTN CONVECTION OVR THE WEST INTERIOR AND VCNTY OF TJMZ AND TJPS .NO OTHER SIG WX IMPACTS AT THIS TIME. && .PREV DISCUSSION... /ISSUED 521 AM AST MON AUG 20 2012/ SYNOPSIS...AT UPPER LEVELS...A LOW NORTHEAST OF THE AREA WILL BE PUSHED WEST BY ADVANCING HIGH PRESSURE THAT WILL PASS NORTH OF THE AREA WEDNESDAY NIGHT. ON THURSDAY ANOTHER STRONG LOW WILL MOVE INTO A POSITION 950 MILES EAST NORTHEAST OF SAN JUAN. IT WILL DRIFT NORTH OVER THE WEEKEND LEAVING HIGH PRESSURE NORTHWEST OF PUERTO RICO IN CONTROL OVER PUERTO RICO AND THE U.S. VIRGIN ISLANDS. AT MID AND LOWER LEVELS...HIGH PRESSURE NORTH OF THE AREA WILL MOVE NORTHEAST AND FILL THE CENTRAL ATLANTIC BY THE WEEKEND. A TROUGH NEAR 57 WEST WILL MOVE OVER THE LOCAL AREA ON TUESDAY WHILE WEAKENING. A STRONG TROPICAL WAVE NEAR 43 WEST WILL CROSS THROUGH AND SOUTH OF THE AREA WEDNESDAY NIGHT AND THURSDAY WITH HIGH PROBABILITIES OF DEVELOPING A TROPICAL STORM BEFORE WEDNESDAY. LOW PRESSURE WILL DEEPEN OVER 50 WEST AT MID LEVELS ON THURSDAY BUT WEAKEN BEFORE MOVING ACROSS 60 WEST ON SUNDAY. ANOTHER LOW PRESSURE WILL MOVE INTO THE CARIBBEAN ON MONDAY OF NEXT WEEK. DISCUSSION...A FEW SHOWERS WERE SEEN OVER THE ATLANTIC AND CARIBBEAN WATERS SURROUNDING EASTERN PUERTO RICO...CULEBRA AND VIEQUES...BUT LITTLE RAIN OF SIGNIFICANCE WAS SEEN. A WEAK TROUGH HAS BEEN ANALYZED NEAR 57 WEST AND IS FOLLOWED BY A BAND OF CLOUDS AND SHOWERS NEAR 53 WEST ALL MOVING TOWARD THE AREA AT AROUND 20 KNOTS. THESE SHOULD ARRIVE BY TUESDAY BUT MAY BE WEAKER THAN THEY ARE NOW. BEHIND THIS IS A TROPICAL WAVE NEAR 43 WEST LATITUDE. IT IS ENSHROUDED TO THE NORTH BY A MODERATELY THICK CLOUD OF DUST AND HAS BOTH A STRONG FEED OF MOISTURE IN ITS EASTERN QUADRANT FROM THE SOUTH AND DRIER AIR WRAPPING AROUND IT COUNTER CLOCKWISE AND COMING IN FROM THE SOUTHWEST. THIS DRIER...DUST LADEN AIR HAS LIKELY BEEN THE CULPRIT THAT HAS CONFOUNDED THE MODELS PERSISTENT FORECASTS OF DEVELOPMENT OF A TROPICAL STORM IN 12 TO 24 HOURS OVER THE LAST SEVERAL DAYS. NEVERTHELESS SAID DEVELOPMENT IS LIKELY WITHIN THE NEXT 48 HOURS AND LIKELY BEFORE IT REACHES THE WINDWARD ISLANDS...EVEN THOUGH THE GFS IS VERY AMBIVALENT ABOUT A CLOSED CIRCULATION AT 700 MB...EVEN BY WEDNESDAY NIGHT. THE CURRENT FORECAST STRADDLES A STRONG TROPICAL WAVE PASSAGE AND A TROPICAL STORM PASSING ALONG THE SOUTHERN BORDER OF THE FORECAST AREA. THIS WILL BRING STRONG GUSTY WINDS AND HEAVY RAINS TO MOST OF PUERTO RICO...THE U.S. VIRGIN ISLANDS AND THE CARIBBEAN WITH CONDITIONS LIKELY SPREADING OVER THE ATLANTIC DEPENDING ON HOW THE SYSTEM DEVELOPS. A GOOD DEAL OF UNCERTAINTY ABOUT THIS SYSTEM EXISTS...AND CAN BE TRACED BACK TO THE PROBLEM OF WHETHER A TROPICAL STORM WILL ACTUALLY DEVELOP OR WHETHER THE SYSTEM WILL CONTINUE INTO THE CARIBBEAN AS A WAVE OR TROPICAL DEPRESSION. THIS ALSO AFFECTS THE TIMING...WITH THE GFS STILL NUDGING THE LOW PRESSURE... THAT PASSES TO OUR SOUTH...AHEAD IN TIME AS TROPICAL CYCLONE FORMATION IS DELAYED. NEVERTHELESS WE EXPECT SERIOUS RAIN TO BEGIN SPREADING ACROSS THE AREA ON WEDNESDAY AND TO CONTINUE INTO THURSDAY...WITH LINGERING EFFECTS INTO FRIDAY. ANOTHER TROPICAL WAVE IS FORECAST BY THE GFS TO CROSS THROUGH THE AREA ON TUESDAY...BUT SCATTERED SHOWERS WOULD CONTINUE ACROSS THE AREA IN THE INTERIM. AVIATION... VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS ACROSS MOST OF THE LOCAL TAF SITES. HOWEVER...BRIEF PERIODS OF MVFR CONDITIONS WITH MOUNTAIN OBSCURATIONS ARE POSSIBLE THIS AFTERNOON OVER TJMZ IN SHRA/TSRA. WINDS WILL CONTINUE MAINLY EAST AT 10 TO 15 KTS. MARINE...SEAS OF 6 FEET OR LESS ARE EXPECTED TO CONTINUE IN THE FORECAST AREA TODAY AND TONIGHT. HOWEVER AS WINDS INCREASE... EXPECT SEAS TO FOLLOW ALSO SUCH THAT 7 FOOT SEAS ARE POSSIBLE BY TUESDAY. SEAS WILL INCREASE UP TO 12 FEET IN EXPOSED AREAS THROUGH THURSDAY. MARINERS SHOULD SEEK FURTHER DETAILS IN THE COASTAL WATERS FORECAST AND THE MARINE WEATHER MESSAGE. CONDITIONS WILL IMPROVE OVER THE FOLLOWING WEEKEND BUT SEAS ARE EXPECTED TO INCREASE AGAIN FROM THE EAST AFTER SUNDAY. HYDROLOGY...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BEGIN INCREASING OVER THE AREA BEGINNING WEDNESDAY AND SIGNIFICANT AMOUNTS OF RAIN ARE POSSIBLE OVER THE FORECAST AREA FROM NOON WEDNESDAY TO NOON THURSDAY WITH AMOUNTS IN SOME AREAS POSSIBLY EXCEEDING 6 TO 8 INCHES...ESPECIALLY IN HIGHER ELEVATIONS. ALTHOUGH RIVER LEVELS ARE FAIRLY LOW...RAPID RISES WOULD BE EXPECTED AND SOME RIVERS AND MANY SMALL STREAM WILL LIKELY FLOOD DURING THE PASSAGE OF THIS TROPICAL WAVE. A THREAT OF MUDSLIDES ALSO EXISTS. SHOULD A TROPICAL STORM FORM...THE AMOUNTS OF RAIN RECEIVED WOULD BE HIGHLY DEPENDENT ON THE TRACK AND COULD BE EITHER HIGHER OR LOWER. && .PRELIMINARY POINT TEMPS/POPS... SJU 90 80 89 80 / 20 30 20 40 STT 91 80 90 81 / 20 20 20 40 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 6 AM AST FRIDAY FOR ANEGADA PASSAGE SOUTHWARD TO 17N. SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO NOON AST FRIDAY FOR CARIBBEAN WATERS OF PUERTO RICO FROM 10 NM TO 17N. && $$ |
| #535582 (Received by flhurricane at: 5:24 AM 20.Aug.2012) AFDSJU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 521 AM AST MON AUG 20 2012 .SYNOPSIS...AT UPPER LEVELS...A LOW NORTHEAST OF THE AREA WILL BE PUSHED WEST BY ADVANCING HIGH PRESSURE THAT WILL PASS NORTH OF THE AREA WEDNESDAY NIGHT. ON THURSDAY ANOTHER STRONG LOW WILL MOVE INTO A POSITION 950 MILES EAST NORTHEAST OF SAN JUAN. IT WILL DRIFT NORTH OVER THE WEEKEND LEAVING HIGH PRESSURE NORTHWEST OF PUERTO RICO IN CONTROL OVER PUERTO RICO AND THE U.S. VIRGIN ISLANDS. AT MID AND LOWER LEVELS...HIGH PRESSURE NORTH OF THE AREA WILL MOVE NORTHEAST AND FILL THE CENTRAL ATLANTIC BY THE WEEKEND. A TROUGH NEAR 57 WEST WILL MOVE OVER THE LOCAL AREA ON TUESDAY WHILE WEAKENING. A STRONG TROPICAL WAVE NEAR 43 WEST WILL CROSS THROUGH AND SOUTH OF THE AREA WEDNESDAY NIGHT AND THURSDAY WITH HIGH PROBABILITIES OF DEVELOPING A TROPICAL STORM BEFORE WEDNESDAY. LOW PRESSURE WILL DEEPEN OVER 50 WEST AT MID LEVELS ON THURSDAY BUT WEAKEN BEFORE MOVING ACROSS 60 WEST ON SUNDAY. ANOTHER LOW PRESSURE WILL MOVE INTO THE CARIBBEAN ON MONDAY OF NEXT WEEK. && .DISCUSSION...A FEW SHOWERS WERE SEEN OVER THE ATLANTIC AND CARIBBEAN WATERS SURROUNDING EASTERN PUERTO RICO...CULEBRA AND VIEQUES...BUT LITTLE RAIN OF SIGNIFICANCE WAS SEEN. A WEAK TROUGH HAS BEEN ANALYZED NEAR 57 WEST AND IS FOLLOWED BY A BAND OF CLOUDS AND SHOWERS NEAR 53 WEST ALL MOVING TOWARD THE AREA AT AROUND 20 KNOTS. THESE SHOULD ARRIVE BY TUESDAY BUT MAY BE WEAKER THAN THEY ARE NOW. BEHIND THIS IS A TROPICAL WAVE NEAR 43 WEST LATITUDE. IT IS ENSHROUDED TO THE NORTH BY A MODERATELY THICK CLOUD OF DUST AND HAS BOTH A STRONG FEED OF MOISTURE IN ITS EASTERN QUADRANT FROM THE SOUTH AND DRIER AIR WRAPPING AROUND IT COUNTER CLOCKWISE AND COMING IN FROM THE SOUTHWEST. THIS DRIER...DUST LADEN AIR HAS LIKELY BEEN THE CULPRIT THAT HAS CONFOUNDED THE MODELS PERSISTENT FORECASTS OF DEVELOPMENT OF A TROPICAL STORM IN 12 TO 24 HOURS OVER THE LAST SEVERAL DAYS. NEVERTHELESS SAID DEVELOPMENT IS LIKELY WITHIN THE NEXT 48 HOURS AND LIKELY BEFORE IT REACHES THE WINDWARD ISLANDS...EVEN THOUGH THE GFS IS VERY AMBIVALENT ABOUT A CLOSED CIRCULATION AT 700 MB...EVEN BY WEDNESDAY NIGHT. THE CURRENT FORECAST STRADDLES A STRONG TROPICAL WAVE PASSAGE AND A TROPICAL STORM PASSING ALONG THE SOUTHERN BORDER OF THE FORECAST AREA. THIS WILL BRING STRONG GUSTY WINDS AND HEAVY RAINS TO MOST OF PUERTO RICO...THE U.S. VIRGIN ISLANDS AND THE CARIBBEAN WITH CONDITIONS LIKELY SPREADING OVER THE ATLANTIC DEPENDING ON HOW THE SYSTEM DEVELOPS. A GOOD DEAL OF UNCERTAINTY ABOUT THIS SYSTEM EXISTS...AND CAN BE TRACED BACK TO THE PROBLEM OF WHETHER A TROPICAL STORM WILL ACTUALLY DEVELOP OR WHETHER THE SYSTEM WILL CONTINUE INTO THE CARIBBEAN AS A WAVE OR TROPICAL DEPRESSION. THIS ALSO AFFECTS THE TIMING...WITH THE GFS STILL NUDGING THE LOW PRESSURE... THAT PASSES TO OUR SOUTH...AHEAD IN TIME AS TROPICAL CYCLONE FORMATION IS DELAYED. NEVERTHELESS WE EXPECT SERIOUS RAIN TO BEGIN SPREADING ACROSS THE AREA ON WEDNESDAY AND TO CONTINUE INTO THURSDAY...WITH LINGERING EFFECTS INTO FRIDAY. ANOTHER TROPICAL WAVE IS FORECAST BY THE GFS TO CROSS THROUGH THE AREA ON TUESDAY...BUT SCATTERED SHOWERS WOULD CONTINUE ACROSS THE AREA IN THE INTERIM. && .AVIATION... VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS ACROSS MOST OF THE LOCAL TAF SITES. HOWEVER...BRIEF PERIODS OF MVFR CONDITIONS WITH MOUNTAIN OBSCURATIONS ARE POSSIBLE THIS AFTERNOON OVER TJMZ IN SHRA/TSRA. WINDS WILL CONTINUE MAINLY EAST AT 10 TO 15 KTS. && .MARINE...SEAS OF 6 FEET OR LESS ARE EXPECTED TO CONTINUE IN THE FORECAST AREA TODAY AND TONIGHT. HOWEVER AS WINDS INCREASE... EXPECT SEAS TO FOLLOW ALSO SUCH THAT 7 FOOT SEAS ARE POSSIBLE BY TUESDAY. SEAS WILL INCREASE UP TO 12 FEET IN EXPOSED AREAS THROUGH THURSDAY. MARINERS SHOULD SEEK FURTHER DETAILS IN THE COASTAL WATERS FORECAST AND THE MARINE WEATHER MESSAGE. CONDITIONS WILL IMPROVE OVER THE FOLLOWING WEEKEND BUT SEAS ARE EXPECTED TO INCREASE AGAIN FROM THE EAST AFTER SUNDAY. && .HYDROLOGY...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BEGIN INCREASING OVER THE AREA BEGINNING WEDNESDAY AND SIGNIFICANT AMOUNTS OF RAIN ARE POSSIBLE OVER THE FORECAST AREA FROM NOON WEDNESDAY TO NOON THURSDAY WITH AMOUNTS IN SOME AREAS POSSIBLY EXCEEDING 6 TO 8 INCHES...ESPECIALLY IN HIGHER ELEVATIONS. ALTHOUGH RIVER LEVELS ARE FAIRLY LOW...RAPID RISES WOULD BE EXPECTED AND SOME RIVERS AND MANY SMALL STREAM WILL LIKELY FLOOD DURING THE PASSAGE OF THIS TROPICAL WAVE. A THREAT OF MUDSLIDES ALSO EXISTS. SHOULD A TROPICAL STORM FORM...THE AMOUNTS OF RAIN RECEIVED WOULD BE HIGHLY DEPENDENT ON THE TRACK AND COULD BE EITHER HIGHER OR LOWER. && .PRELIMINARY POINT TEMPS/POPS... SJU 90 80 89 80 / 20 30 20 40 STT 91 80 90 81 / 20 20 20 40 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO NOON AST THURSDAY FOR ANEGADA PASSAGE SOUTHWARD TO 17N. SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 6 AM AST FRIDAY FOR CARIBBEAN WATERS OF PUERTO RICO FROM 10 NM TO 17N. && $$ |
