000 AGXX40 KNHC 041926 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 326 PM EDT TUE JUN 4 2013 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: LOW TO AVERAGE CONFIDENCE WITH RESPECT TO POSITION AND INTENSITY OF FORECAST SURFACE LOW. BLEND OF THE PREVIOUS FORECAST WITH THE GFS AND ECMWF. RIDGE OF HIGH PRES IS NOW OVER THE EXTREME FAR NE CORNER OF THE GULF. THE MAIN FEATURE OF INTEREST CONTINUES TO BE A SURFACE TROUGH THAT AS OF 18 UTC EXTENDS FROM THE N CENTRAL YUCATAN PENINSULA NNE TO NEAR 28N87W. THIS FEATURE COMPOSES A PERSISTENT BROAD AREA OF LOW PRES THAT ENCOMPASSES THE CENTRAL AND ERN PORTIONS OF THE GULF. LATEST SATELLITE DISPLAYS AND NWS RADAR IMAGERY SHOW QUITE AN EXTENSIVE AREA OF VERY ACTIVE DEEP TSTM ACTIVITY WITH SQUALLS EAST OF THE TROUGH DUE TO STRONG UPPER DIFFLUENT PATTERN E OF AN UPPER LEVEL TROUGH ALONG 87W. LATEST BUOY DATA ALONG WITH SEVERAL SHIP REPORTS DEPICT MODERATE TO FRESH WINDS EAST OF THE SURFACE TROUGH...WITH POCKETS OF LOCALLY STRONG WINDS ESPECIALLY IN THE FAR SE PART OF THE GULF. THIS IS ALSO WHERE THE 1512 UTC ASCAT PASS INDICATED A LARGE SWATH OF SE 20-25 KT WINDS. GENTLE TO MODERATE WINDS PREVAIL WEST OF THE SURFACE TROUGH. SEAS ARE IN THE 3-5 FT RANGE OVER THE NE GULF...6-9 FT OVER THE SE GULF...AND 1-3 FT OVER THE REMAINDER OF THE GULF WATERS. THE GENERAL FORECAST SCENARIO REMAINS THE SAME WITH THE TROUGH PREVAILING OVER THE NEXT 3-4 DAYS AND EXPECTED FORMATION OF A SURFACE LOW OVER THE NEXT FEW DAYS. THE TROUGH AND LOW WILL SHIFT NE AHEAD OF A MID-LATITUDE TROUGH DIGGING INTO THE SE UNITED STATES LATER IN THE WEEK. LATEST SATELLITE IMAGERY SHOWS WHAT APPEARS TO BE A LOW FORMING ON THE TROUGH AXIS NEAR 23N88W. THIS FEATURE...OR THE ONE THAT DOES BECOME THE MORE DEFINITIVE LOW ASSOCIATED WITH THE AFOREMENTIONED TROUGH WILL HAVE A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS. AS FOR MODEL DEPICTIONS...AS STATED IN PREVIOUS FORECASTS... UNCERTAINTY STILL REMAINS WITH REGARDS TO THE STRENGTH OF THE LOW EXPECTED TO FORM. THE GFS IS APPEARING SIMILAR TO THE ECMWF WITH REGARD TO THE WIND FIELD RELATED TO THE UPCOMING LOW FEATURE. THE UKMET CONTINUES TO BE MUCH STRONGER WITH THE SURFACE WINDS AND RESULTING SEAS OVER THE EASTERN GULF OF MEXICO THROUGH THE REMAINDER OF THE WEEK...BUT HAS COME MORE IN LINE WITH THE FUTURE TRACK OF THE EXPECTED LOW FEATURE IN COMPARISON TO THE OTHER GLOBAL MODELS. THE MAIN POINT HERE IS THAT IT IS THAT ONCE THE LOW HAS DEVELOPED IT IS ANTICIPATED THAT IT WILL STRENGTHEN AS IT INTERACTS WITH ANOTHER UPPER TROUGH LATER IN THE WEEK. DESPITE THE UNCERTAINTY OF THE WINDS AND SEAS FORECAST OVER THE NEXT SEVERAL DAYS...EXPECT SQUALLY CONDITIONS WITH TSTMS PRODUCING FREQUENT LIGHTNING AT TIMES ACROSS THE ERN GULF OF MEXICO INTO PORTIONS OF FLORIDA THROUGH THE END OF THE WEEK. WILL HIGHLIGHT FUTURE FORECAST CHARTS AND TEXT PRODUCTS WITH "TROPICAL CYCLONE FORMATION POSSIBLE." ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: HIGH CONFIDENCE BLEND OF GFS AND ECMWF WITH THE PREVIOUS FORECAST. AVERAGE CONFIDENCE OVER THE WRN CARIBBEAN RELATED TO CONVECTION AND INDUCED GRADIENT TO THE SE OF THE GULF OF MEXICO TROUGH...AND ITS ASSOCIATED FORECAST LOW THROUGH WED AFTERNOON. A WEAKENING SURFACE RIDGE PREVAILS N OF THE AREA WITH THE MONSOON TROUGH EXTENDING OVER THE SW PORTION OF THE CARIBBEAN SEA. A WEAKENING TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WATERS ALONG A POSITION FROM 21N64W TO 12N65W MOVING W NEAR 15 KT. LATEST SHIP/BUOY OBSERVATIONS DEPICT FRESH TO STRONG WINDS OVER THE CENTRAL CARIBBEAN AND FAR NW CARIBBEAN INTO THE YUCATAN CHANNEL. OTHERWISE...MODERATE TO FRESH WINDS COVER THE MAJORITY OF THE REMAINDER OF THE FORECAST AREA...EXCEPT OVER THE SW CARIBBEAN WATERS WHERE LIGHT TO GENTLE WINDS PREVAIL. SEAS RANGE FROM 8-10 FT OVER THE SOUTH CENTRAL CARIBBEAN...WITH SEAS 6-8 FT OVER THE WRN PART OF THE TROPICAL N ATLC AND FAR NW CARIBBEAN. ELSEWHERE SEAS ARE 5-7 FT OVER THE REMAINDER OF THE FORECAST AREA...EXCEPT IN THE SW CARIBBEAN WHERE SEAS ARE IN THE 2-4 FT RANGE. THE AREA OF HIGH PRES N OF THE AREA WILL WEAKEN SOME AS IT SHIFTS S THROUGH FRI. THIS WILL RESULT IN WINDS WEAKENING SLIGHTLY ACROSS MUCH OF THE FORECAST AREA EXCEPT FOR THE CENTRAL CARIBBEAN AND THE FAR WESTERN CARIBBEAN. SEAS WILL REMAIN AT OR NEAR 8 FT OVER THE CENTRAL CARIBBEAN WATERS THROUGH THE FORECAST PERIOD AND THE TROPICAL N ATLC WATERS THROUGH THE MIDDLE OF THE WEEK. ACTIVE CONVECTION WITH OCCASIONAL SQUALLS AND FRESH TO STRONG WINDS WITH SEAS AT OR NEAR 8 FT WILL CONTINUE OVER THE FAR NW CARIBBEAN INTO THE YUCATAN CHANNEL INTO AT LEAST EARLY ON THU DUE TO THE TROUGHING OVER THE GULF OF MEXICO. WINDS AND SEAS WILL THEN DECREASE LATER THU AND INTO FRI AS THE SURFACE TROUGH/LOW OR POSSIBLE TROPICAL CYCLONE PULLS FURTHER NORTHWARD ACROSS THE ERN GULF. THE TROPICAL WAVE OVER THE EASTERN CARIBBEAN WILL CONTINUE TO MOVE W TROUGH TONIGHT...THEN MORE TO THE NW INTO WED BEFORE IT BECOMES DIFFUSE LATER ON DUE TO UNFAVORABLE UPPER LEVEL CONDITIONS. A SECOND TROPICAL WAVE WILL MOVE INTO THE ERN PORTION OF THE TROPICAL N ATLC WATERS LATE FRI NIGHT INTO SAT...AND ACROSS THE REMAINDER OF THE TROPICAL N ATLC ZONES SUN. A SMALL POCKET OF TIGHT PRES GRADIENT AHEAD OF IT WILL RESULT IN NE WINDS OF 20-25 KT SAT AFTERNOON OVER THE ERN PORTION OF THE TROPICAL N ATLC AS THE WAVE INTERACTS WITH THE SRN PERIPHERY OF THE ATLC SUB-TROPICAL RIDGE BUT THEN SLACKENS LATE SAT INTO SUN. SEAS OF UP TO 9 FT ARE FORECAST AHEAD OF THE WAVE OVER THE FAR NE TROPICAL N ATLC SAT INTO SUN...BUT THEN SUBSIDING TO AROUND 6 FT DURING SUN AFTERNOON. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: HIGH CONFIDENCE BLEND OF THE GFS AND ECMWF WITH THE PREVIOUS FORECAST. THE PRELIMINARY SURFACE ANALYSIS HAS A HIGH PRES RIDGE EXTENDING FROM NEAR 30N65W SW TO THE NW BAHAMAS. LATEST BUOY AND SHIP REPORTS INDICATE GENTLE TO LOCALLY MODERATE WINDS OVER THE N PART OF THE AREA...AND MODERATE TO FRESH WINDS OVER THE REMAINDER OF THE FORECAST AREA WHERE THE GRADIENT IS SLIGHTLY TIGHTER. THE 1412 UTC ASCAT PASS ALSO SUGGESTED THESE WIND CONDITIONS. THE REPORTS INDICATE SEAS IN THE RANGE OF 3-5 FT OVER THE NRN PORTION...AND 4-6 FT OVER THE REMAINDER OF THE FORECAST AREA E OF THE BAHAMAS ...WHILE LOWER SEAS OF 1-3 FT CONTINUING W OF THE BAHAMAS. A DIMINISHING SMALL AREA OF 5-7 FT SEAS IS JUST S OF THE SE BAHAMAS. THE FORECAST REMAINS ON TRACK WITH LITTLE OVERALL CHANGES EXPECTED WITH WINDS AND SEAS THROUGH THU. UPCOMING CHANGES FOR DAYS 4 AND 5 PERTAIN TO PRIMARILY THE NW PORTION OF THE AREA AS AN INDIRECT RESULT OF PRESENT EVOLVING GULF OF MEXICO LOW PRES SYSTEM. THIS SYSTEM IS FORECAST TO APPROACH THE FAR NW CORNER OF THE AREA FRI...BUT STAYING JUST TO THE NW OF THE OFFSHORE WATERS. THE WRN EXTENSION OF THE RIDGE WILL SHIFT S TO THE STRAITS OF FLORIDA FRI AND SAT...THEN VERY SLIGHTLY SAT AND SUN. THE TIGHTENING PRES GRADIENT CREATED BY IT AND THE ABOVE MENTIONED HIGH PRES WILL BE ENOUGH TO SIGNIFICANTLY INCREASE S-SW WINDS ACROSS THE NW PORTION TO 20-25 KT FRI. SEAS THERE ARE FORECAST TO BUILD TO AROUND 9 FT FRI. ON SAT...THESE CONDITIONS BEGIN TO SUBSIDE AND CONTINUE ON THE DOWNWARD TREND THROUGH SUN AS THE LOW HAS PULLED FAR TO THE N OF THE AREA ALLOWING FOR THE GRADIENT TO SLACKEN. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.