000WTNT35 KNHC 012036TCPAT5BULLETINTROPICAL DEPRESSION FIVE ADVISORY NUMBER 1NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012500 PM AST WED AUG 01 2012...TROPICAL DEPRESSION FORMS IN THE TROPICAL ATLANTIC EAST OF THEWINDWARD ISLANDS...SUMMARY OF 500 PM AST...2100 UTC...INFORMATION----------------------------------------------LOCATION...12.2N 49.0WABOUT 810 MI...1305 KM E OF THE WINDWARD ISLANDSMAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HPRESENT MOVEMENT...WNW OR 285 DEGREES AT 18 MPH...30 KM/HMINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHESWATCHES AND WARNINGS--------------------CHANGES WITH THIS ADVISORY...THE GOVERNMENT OF BARBADOS HAS ISSUED A TROPICAL STORM WATCH FORBARBADOS...ST. VINCENT AND THE GRENADINES...AND DOMINICA.THE GOVERNMENT OF ST. LUCIA HAS ISSUED A TROPICAL STORM WATCH FORST. LUCIA.THE GOVERNMENT OF FRANCE HAS ISSUED A TROPICAL STORM WATCH FORMARTINIQUE AND GUADELOUPE.SUMMARY OF WATCHES AND WARNINGS IN EFFECT...A TROPICAL STORM WATCH IS IN EFFECT FOR...* BARBADOS...ST. VINCENT AND THE GRENADINES...AND DOMINICA* ST. LUCIA* MARTINIQUE AND GUADELOUPEINTERESTS ELSEWHERE IN THE LESSER ANTILLES SHOULD MONITOR THEPROGRESS OF THIS SYSTEM.A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS AREPOSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITORPRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.DISCUSSION AND 48-HOUR OUTLOOK------------------------------AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL DEPRESSION FIVEWAS LOCATED NEAR LATITUDE 12.2 NORTH...LONGITUDE 49.0 WEST. THEDEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST NEAR 18 MPH...30KM/H...AND A WEST-NORTHWESTWARD TO WESTWARD MOTION AT ABOUT THE SAMEFORWARD SPEED IS EXPECTED OVER THE NEXT 48 HOURS. ON THE FORECASTTRACK...THE CENTER OF THE TROPICAL CYCLONE SHOULD BE NEAR THEWINDWARD ISLANDS ON FRIDAY.MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/H...WITH HIGHERGUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND THE DEPRESSION COULD BECOME A TROPICAL STORM TONIGHT OR ONTHURSDAY.ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB...29.77 INCHES.HAZARDS AFFECTING LAND----------------------WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREAON FRIDAY.NEXT ADVISORY-------------NEXT INTERMEDIATE ADVISORY...800 PM AST.NEXT COMPLETE ADVISORY...1100 PM AST.$$FORECASTER PASCH
000WTNT45 KNHC 012044TCDAT5TROPICAL DEPRESSION FIVE DISCUSSION NUMBER 1NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012500 PM AST WED AUG 01 2012DURING THE DAY...VISIBLE SATELLITE IMAGES SHOWED THAT THE LOW-LEVELCIRCULATION OF THE LOW PRESSURE SYSTEM TO THE EAST OFTHE WINDWARD ISLANDS HAS BECOME BETTER DEFINED. DEEP CONVECTIONHAS PULSED A BIT...AND IS SOMEWHAT LACKING OVER THE NORTHERN PARTOF THE CIRCULATION. HOWEVER THE SYSTEM HAS NOW ACQUIRED SUFFICIENTORGANIZATION TO BE CLASSIFIED AS A TROPICAL DEPRESSION. THEINITIAL WIND SPEED IS SET AT 30 KT IN ACCORDANCE WITH DVORAKESTIMATES FROM TAFB AND SAB. FORECASTING INTENSITY CHANGE ISALWAYS A CHALLENGE...AND IS PARTICULARLY TRUE IN THIS CASE.MODERATE VERTICAL SHEAR...ASSOCIATED WITH A LARGE UPPER-LEVEL LOWTO THE NORTH OF THE DEPRESSION...IS LIKELY TO AFFECT THE SYSTEM FORTHE NEXT COUPLE OF DAYS. THUS ONLY SLOW STRENGTHENING ISANTICIPATED DURING THE FIRST HALF OF THE FORECAST PERIOD. LATERON...THE INTENSITY FORECAST UNCERTAINTY INCREASES. OUR BEST TWOGLOBAL MODELS ARE AT ODDS AS TO HOW THE SYSTEM WILL EVOLVE AS ITMOVES OVER THE CARIBBEAN. THE GFS FORECASTS THE UPPER-LEVELENVIRONMENT TO BECOME QUITE CONDUCIVE FOR STRENGTHENING BY THE ENDOF THE FORECAST PERIOD...WHEREAS THE ECMWF MODEL SHOWS THE SYSTEMDEGENERATING INTO A TROPICAL WAVE. THE OFFICIAL FORECAST LEANSTOWARD TO THE GFS...BUT TIME WILL TELL.
000WTNT45 KNHC 020240TCDAT5TROPICAL DEPRESSION FIVE DISCUSSION NUMBER 2NWS NATIONAL HURRICANE CENTER MIAMI FL AL0520121100 PM AST WED AUG 01 2012SINCE THE PREVIOUS ADVISORY...CONVECTION ASSOCIATED WITH THEDEPRESSION HAS WANED. HOWEVER...IT IS NOT UNUSUAL FOR CONVECTION TO FLUCTUATE IN ASSOCIATION WITH WEAK AND DEVELOPING TROPICALCYCLONES. EROSION OF THE INNER CORE CONVECTION IS ALSO LIKELY DUETO THE ENTRAINMENT OF DRY MID-LEVEL AIR INTO THE NORTHWEST QUADRANTAS NOTED IN VARIOUS WATER VAPOR PRODUCTS OVER THE PAST 8 HOURS. THEINITIAL INTENSITY REMAINS AT 30 KT...WHICH IS SUPPORTED BY AUW-CIMSS ADT INTENSITY ESTIMATE OF T2.2/32 KT.THE INITIAL MOTION REMAINS 285/16 KT. THERE IS NO SIGNIFICANT CHANGETO THE PREVIOUS FORECAST TRACK OR REASONING. A DEEP-LAYERSUBTROPICAL RIDGE TO THE NORTH OF THE CYCLONE IS EXPECTED TO REMAININ PLACE THROUGH THE FORECAST PERIOD....WHICH SHOULD KEEP THEDEPRESSION MOVING IN A GENERAL WEST-NORTHWESTWARD MOTION THROUGH120 H. THE NHC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON THISSCENARIO...AND THE CURRENT FORECAST TRACK IS JUST AN UPDATE OF THEPREVIOUS ADVISORY TRACK...AND LIES NORTH OF THE MODEL CONSENSUS DUETO THE MORE SOUTHERLY GFDL MODEL TRACK THAT IS CONSIDERED TO BE ANOUTLIER DUE TO IT DEPICTING A MUCH WEAKER SYSTEM THAN FORECAST.ONCE THE AFOREMENTIONED DRY AIR ENTRAINMENT PROCESS ABATES...CONVECTION SHOULD REDEVELOP NEAR THE CENTER SINCE THE SYSTEM STILLHAS A VERY ROBUST CIRCULATION AS NOTED IN RECENT SSMI AND AMSUMICROWAVE SATELLITE DATA. HOWEVER...VERTICAL SHEAR CONDITIONS AREONLY EXPECTED TO BE MARGINALLY CONDUCIVE FOR SLOW DEVELOPMENT TOOCCUR OVER THE NEXT 48-72 HOURS. BY DAYS 4 AND 5...MORE SIGNIFICANTINTENSIFICATION WILL BE POSSIBLE WHEN THE CYCLONE IS LOCATED OVERTHE WARMER CARIBBEAN SEA AND IN A MORE FAVORABLE UPPER-LEVEL WINDENVIRONMENT. THE INTENSITY FORECAST IS SIMILAR TO THE PREVIOUSADVISORY...AND IS CLOSE TO A BLEND OF THE SHIPS AND LGEM INTENSITYFORECAST MODELS.FORECAST POSITIONS AND MAX WINDSINIT 02/0300Z 12.6N 50.6W 30 KT 35 MPH 12H 02/1200Z 13.0N 53.0W 35 KT 40 MPH 24H 03/0000Z 13.6N 56.1W 40 KT 45 MPH 36H 03/1200Z 14.2N 59.3W 45 KT 50 MPH 48H 04/0000Z 14.7N 62.5W 50 KT 60 MPH 72H 05/0000Z 15.8N 68.5W 55 KT 65 MPH 96H 06/0000Z 16.8N 74.3W 60 KT 70 MPH120H 07/0000Z 17.8N 78.7W 65 KT 75 MPH$$FORECASTER STEWART
000WTNT45 KNHC 020841TCDAT5TROPICAL DEPRESSION FIVE DISCUSSION NUMBER 3NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012500 AM AST THU AUG 02 2012THUNDERSTORM ACTIVITY ASSOCIATED WITH THE DEPRESSION HAS GENERALLYDIMINISHED DURING THE LAST SEVERAL HOURS...WITH DEEP CONVECTION NOWCONFINED TO THE SOUTH OF THE LOW-LEVEL CENTER. ALTHOUGH DVORAKT-NUMBERS HAVE DECREASED TO 1.5 AND 1.0 FROM TAFB AND SAB...THEINITIAL INTENSITY IS HELD AT 30 KT. THERE IS A POSSIBILITY THAT THEDEPRESSION COULD DEGENERATE INTO A REMNANT LOW OR TROPICAL WAVELATER TODAY IF THE CURRENT WEAKENING TREND CONTINUES. IF THIS ISTHE CASE...THEN ADJUSTMENTS TO THE TROPICAL STORM WATCH MAY BENECESSARY.UW-CIMSS AND SHIPS ANALYSES INDICATE 20 KT OF WESTERLY SHEAR...ASSOCIATED WITH AN UPPER-LEVEL TROUGH TO THE NORTH...AFFECTING THECYCLONE. THE GUIDANCE SHOWS A CONTINUATION OF THIS SHEAR OVER THEDEPRESSION THROUGH THE NEXT COUPLE OF DAYS...ESPECIALLY SINCE THESYSTEM WILL BE MOVING INTO AN ENVIRONMENT CHARACTERIZED BY STRONGLOW- TO MID-LEVEL EASTERLY FLOW AND WEAKER FLOW ALOFT. ASSUMING THESYSTEM SURVIVES...GLOBAL MODELS SHOW A MORE FAVORABLE ENVIRONMENTOVER THE WESTERN CARIBBEAN IN 4-5 DAYS...WHERE INTENSIFICATION COULDOCCUR. GIVEN THE CURRENT TREND...THE NHC INTENSITY FORECAST ISREDUCED...ESPECIALLY EARLY IN THE FORECAST PERIOD...AND IS LINEWITH THE LATEST SHIPS/LGEM OUTPUT.