000 AGXX40 KNHC 061840 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 240 PM EDT WED AUG 6 2014 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: GFS AND LATEST MWW3 BLEND WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. IN THE UPPER LEVELS...AN ELONGATED TROUGH CONTINUES TO STRETCH FROM THE EASTERN U.S. SW ACROSS THE WESTERN FLORIDA PANHANDLE TO TO AN ELONGATED TUTT LOW MOVING WNW NEAR 21N96W. TO THE NW OF THE TROUGH...WATER VAPOR IMAGERY SHOWS RATHER DRY AND STABLE CONDITIONS WHILE TO THE E OF THE TROUGH PLENTIFUL DEEP LAYER MOISTURE PERSISTS HELPING TO TRIGGER OFF SCATTERED SHOWERS AND ISOLATED TSTMS MAINLY S OF 25N E OF 89W. AT THE SFC...A WEAK RIDGING IN PLACE IS KEEPING A LIGHT PRES GRADEINT THROUGHOUT. THIS IS ALLOWING FOR SEAS TO CONTINUE ON THE LOW SIDE...WITH RANGES IN THE 0-2 FT...EXCEPT FOR SMALL POCKETS OF 2-3 FT SEAS ARE OVER THE EASTERN PORTION OF THE SW GULF. LITTLE OVERALL CHANGES IN THE PRESENT SYNOPTIC PATTERN WILL ALLOW FOR TRANQUIL CONDITIONS TO LAST OVER THE NEXT SEVERAL DAYS. THE RIDGE WILL GRADUALLY TRANSLATE NORTHWARD TO NEAR 28N BY FRI...AND PERSIST THERE THROUGH MON. IT STILL APPEARS THAT SOME ENERGY ASSOCIATED WITH THE NORTHERN PORTION OF A TROPICAL WAVE CURRENTLY OVER THE CARIBBEAN ALONG 70W MAY MOVE THROUGH THE STRAITS OF FLORIDA AND FAR SE GULF FRI INTO SAT...AND POSSIBLY THROUGH SW GULF SAT NIGHT THROUGH SUN BUT SHOULD BE SUBTLE IN NATURE. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS BLEND WITH PREVIOUS OFFICIAL FOR WINDS. FOR WAVEHEIGHTS...AN EVEN BLEND OF THE 12 MWW3 AND NWPS PARAMETERS WITH PREVIOUS OFFICIAL. LATEST SURFACE ANALYSIS HAS LARGE AMPLITUDE TROPICAL WAVES OVER THE CARIBBEAN WITH THE FIRST ONE ALONG 70W EXTENDING AS NORTHWARD TO 23N. TO ITS W...ANOTHER WAVE IS JUST E OF HONDURAS AND NICARAGUA EXTENDING N TO NEAR 20N. THE WAVES ARE MOVING W ABOUT 15-20 KT. A TROUGH IS ROUGHLY ALONG 51W/52W FROM 09N TO 18N IS MOVING W AT 15 KT. DEEP LAYER MOISTURE AND UPPER LEVEL DIFFLUENCE ARE SUPPORTING SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 240 NM W OF THE TROUGH FROM 10N TO 14N. ISOLATED SHOWERS AND AND TSTMS ARE WITHIN 120 NM E OF THE TROUGH FROM 10N TO 14N. PARTIAL ASCAT DATA FROM THIS MORNING SHOWED GENERALLY GENTLE TO MODERATE ELY TRADES OVER MUCH OF THE AREA. LIGHTER WINDS ARE OVER THE NORTHERN SECTIONS OF THE EASTERN AND WESTERN CARIBBEAN...AND OVER THE FAR SOUTHERN PART OF THE TROPICAL N ATLC. A SMALL PATCH OF NE TO E 20 KT WINDS IS PRESENT FROM 11N TO 13N BETWEEN 72W AND 77W. SEAS THERE ARE IN THE 6-8 FT RANGE. SEAS ELSEWHERE ARE LOW AS 2-4 FT WERE INDICATED IN THE NW CARIBBEAN. AS THE WAVES TRACK WESTWARD OVER THE NEXT 48 HRS...THE ATLC RIDGE WILL SLOWLY BUILD SW INTO BAHAMAS BUT SHOULD BE RATHER WEAK. ONCE THE WAVE OVER THE EASTERN CARIBBEAN SEA MOVES INTO NW CARIBBEAN AND STRAITS BY THE END OF THE WEEK...THE RIDGE WILL BEGIN TO STRENGTHEN SLIGHTLY ACROSS THE REGION FRI THROUGH MON ALLOWING FOR THE PRES GRADIENT TO INCREASE SOMEWHAT MORE OVER MUCH OF THE CENTRAL CARIBBEAN WITH NE WINDS POSSIBLY REACHING THE RANGE OF 20-25 KT OVER THE S CENTRAL CARIBBEAN. THE TROUGH ALONG 51W/52W WILL SOON BE IDENTIFIED AS A TROPICAL WAVE ON THE SURFACE MAP. THIS FEATURE WILL ENTER THE EASTERN TROPICAL N ATLC WATERS THIS EVENING...AND MOVE ACROSS THE REMAINDER OF THOSE WATERS THROUGH THU NIGHT...THEN ENTER THE FAR EASTERN CARIBBEAN FRI...AND CONTINUE ACROSS THE EASTERN CARIBBEAN THROUGH SAT BEFORE ENTERING THE CENTRAL CARIBBEAN ON SUN AND GRADUALLY LOSE ITS DEFINITION...AS WHAT HAS BEEN THE TREND WITH THE PREVIOUS TROPICAL WAVES...AS IT MIGRATES INTO THE WESTERN PART OF THE CARIBBEAN SEA ON MON. A SLIGHTER TIGHTER PRES GRADIENT IN ITS WAKE SHOULD ALLOW FOR WINDS TO BE AT 15-20 KT OVER MUCH OF THE EASTERN PART OF THE EASTERN CARIBBEAN IN ADDITION TO THE 20-25 KT WINDS EXPECTED OVER THE S CENTRAL CARIBBEAN AS MENTIONED ABOVE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS BLEND WITH PREVIOUS OFFICIAL FOR WINDS. FOR WAVEHEIGHTS...A BLEND OF THE 12 MWW3 AND NWPS PARAMETERS WITH PREVIOUS OFFICIAL. A SURFACE TROUGH EXTENDS FROM FROM 31N72W TO JUST E OF THE FLORIDA KEYS W TO CAPE CANAVERAL FLORIDA EARLY THIS AFTERNOON. HIGH PRES RIDING IS ANALYZED TO ITS SE FROM NEAR 27N65W TO THE CENTRAL BAHAMAS AREA. SCATTERED TSTMS ARE NOTED N OF 27N WITHIN 60 NM SE OF THE TROUGH. SE SWELLS HAVE DISSIPATED MUCH SINCE YESTERDAY...BUT ARE BRINGING SEAS OF 5-7 FT ARE N OF 28N BETWEEN 72W AND 76W. THIS SWELL WILL SLOWLY SUBSIDE THROUGH THU. THE ASCAT PASS FROM 1456 UTC THIS MORNING DEPICTED A SWATH OF S-SW 20-25 KT WINDS N OF 30N WITHIN 180 NM E OF THE TROUGH. THE TROUGH WILL SLIDE EASTWARD THROUGH FRI NIGHT...WHILE IT WEAKENS. THE RIDGE WILL SHIFT SOUTHWARD TO NEAR 26N TONIGHT INTO THU...AND PERSIST UNTIL LATE SAT BEFORE IT SHIFTS TO A POSITION FROM NEAR 31N77W TO 26N65W THROUGH MON. AN UPPER LEVEL LOW TO THE NW OF THE CARIBBEAN TROPICAL WAVE ALONG 70W WILL BRING SOME INCREASE OF MOISTURE WITH SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE FAR WATERS THROUGH THU WHILE SPREADING WESTWARD. THIS ACTIVITY THEN SPREAD MORE TO THE NW FRI AND SAT AROUND THE RIDGE TO VICINITY BETWEEN THE BAHAMAS AND S FLORIDA...HOWEVER MOISTURE PROGS SUGGEST THAT THIS MOISTURE WILL BE DECREASING WITH TIME. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.