000 AGXX40 KNHC 211905 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT TUE AUG 21 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE MAIN FEATURE THAT IS OVER THE AREA IS A RATHER PERSISTENT TROUGH THAT EXTENDS FROM THE FLORIDA BIG BED AREA SW TO NEAR 25N96W. THE OTHER FEATURE IS LOW PRES OF 1010 MB IN THE SW GULF JUST E OF THE NE MEXICAN COAST AT 24N97W. A TROUGH EXTENDS NE FROM THIS FEATURE TO THE FIRST TROUGH. THE WRN EXTENSION OF A WEAK ATLC RIDGE EXTENDS SW INTO THE GULF TO NEAR 24N86W. LATEST SATELLITE IMAGERY ALONG WITH NWS RADAR IMAGERY SHOW SCATTERED TSTMS WITH MANY LIGHTNING STRIKES ALONG AND WITHIN 120 NM SE OF THE FIRST TROUGH...AND ALSO WITHIN 240 NM OF THE LOW IN THE E SEMICIRCLE. CURRENT AND LATEST BUOY AND OIL RIG PLATFORM OBSERVATIONS SHOW S-SW WINDS OF 15-20 KT BETWEEN THE RIDGE AND THE TROUGH E OF 87W. THE WRN EDGE OF AN ASCAT PASS FROM 1452 UTC THIS MORNING REVEALED SUCH WINDS BETWEEN THE TROUGH. GENERAL RANGES OF SEAS ARE 2-3 FT OVER MUCH OF THE GULF...EXCEPT FOR SMALL POCKETS OF 3-5 FT IN THE ERN GULF ZONES AND IN THE SW PORTION OF THE NEAR AND W OF THE LOW. HIGHER WINDS AND SEAS ARE POSSIBLE WITH THE TSTM ACTIVITY MENTIONED ABOVE. THE REPORTED SEA HEIGHT VALUES AGAIN FALL PRETTY CLOSE TO THOSE ADVERTISED BY THE 12 UTC NOAA III WAVEWATCH MODE RUN. WILL AGAIN FOLLOW THIS GUIDANCE CLOSELY FOR THIS FORECAST PACKAGE FOR SEAS IN THE GULF...EXCEPT WILL GO HIGHER THAN GUIDANCE FOR SEAS IN THE WRN PORTION OF THE SW GULF NEAR AND W OF THE LOW THROUGH WED MORNING TO ACCOUNT FOR THE POSSIBILITY OF THE LOW STRENGTHENING...SINCE IT HAS A LOW CHANCE OF TROPICAL DEVELOPMENT THROUGH THE NEXT 48 HRS. THE WEATHER WILL REMAIN UNSETTLED OVER MUCH OF THE NRN GULF WATERS THROUGH FRI AS THE SURFACE TROUGH SLOWLY MOVES E THROUGH FRI AND DISSIPATES. A STATIONARY FRONTAL BOUNDARY JUST INLAND THE NORTHERN GULF COAST WILL BEGIN TO MOVE S AS A WEAK COLD FRONT THROUGH WED NIGHT BEFORE IT BECOMES STATIONARY AGAIN. THIS FRONT WILL THEN DISSIPATE OVER THE N CENTRAL WATERS THU AND FRI. NEARLY STATIONARY WEAK LOW PRES OF 1010 MB ALONG THE NE MEXICAN COAST AT 24N97W IS FORECAST TO BEGIN TO TRACK WESTWARD THIS AFTERNOON...AND MOVE INLAND THE NE MEXICAN COAST EARLY ON WED. THE NORTHERN PORTION OF A TROPICAL WAVE JUST E OF THE YUCATAN PENINSULA WILL MOVE INLAND TONIGHT...THEN ACROSS THE SW GULF WED THROUGH THU. MODEL INDICATIONS ARE THAT THIS FEATURE WILL BE RATHER WEAK... AND SHOULD HAVE LITTLE IMPACT ON WINDS AND SEAS AS IT LOSES ITS IDENTITY IN THE SW PART OF THE GULF. THERE MAY BE A FEW BRIEFLY OF E-SE WINDS OF 15 KT BEHIND THE WAVE ALONG WITH ISOLATED TO WIDELY SCATTERED SHOWERS AND TSTMS THAT MAY ACCOMPANY IT. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... A TROPICAL WAVE IS JUST E OF THE YUCATAN PENINSULA AND BELIZE EARLY THIS AFTERNOON MOVING W AT ABOUT 15 KT. THIS WAVE WILL WILL MOVE INLAND THE YUCATAN PENINSULA AND ENTER THE FAR SRN TONIGHT. THE COMBINATION OF ATLC RIDGING AND BROAD LOW PRES OVER THE SE CARIBBEAN SEA IS RESULTING IN NE-E WINDS OF 20-25 KT IN THE SW PORTION OF THE SEA JUST NW OF THE COLOMBIAN COAST FROM ABOUT 12N TO 15N AND BETWEEN 72W-79W. THE PARTIAL ASCAT PASS FROM 1454 UTC THIS MORNING CAPTURED THE EDGE OF THE ERN EDGE OF THESE WINDS. THESE WINDS ARE FORECAST TO DIMINISH BY LATE WED NIGHT. SE WINDS OF 20-25 KT ACROSS THE GULF OF HONDURAS WILL CONTINUE INTO WED...THEN DIMINISH TO 20 KT WINDS OR LESS WED NIGHT. A TROPICAL WAVE EXTENDING FROM THE LEEWARD ISLANDS TO 10N64W IS MOVING W AROUND 18 KT. THIS WAVE WILL MOVE ACROSS THE REST OF THE EASTERN CARIBBEAN THROUGH WED MORNING...ACROSS THE CENTRAL CARIBBEAN LATER WED THROUGH THU MORNING...AND ACROSS THE WESTERN CARIBBEAN FRI AND SAT. NE-E WINDS OF 15-20 KT WILL ACCOMPANY THE WAVE N OF 15N AS IT MOVED ACROSS THE AFFECTED ZONES. WILL AGAIN UTILIZE THE GFS/ECMWF 10 M WIND GUIDANCE FIELD AND FOR THESE WINDS WITH THE WAVE AS FOR POSITIONS. AGAIN...AS STATED IN PREVIOUS FORECAST DISCUSSIONS THE MAIN FOCUS FOR UPCOMING FEATURES TO AFFECT THE FORECAST WATERS WILL BE TROPICAL DEPRESSION NINE LOCATED AT 15.3N 53.2W 1008 MB AT 2 PM EDT IS MOVING W AT 17 KT. MAXIMUM SUSTAINED WINDS 30 KT GUSTS 40 KT. TROPICAL DEPRESSION NINE IS FORECAST TO STRENGTHEN TO A TROPICAL STORM AS IT MOVES TO NEAR 15.2N 55.3W EARLY TONIGHT AND CONTINUE TO STRENGTHEN AS IT REACHES NEAR 15.5N 58.4W WED MORNING...NEAR 15.9N 61.5W EARLY WED EVENING. IT IS THEN FORECAST TO BECOME A MINIMAL HURRICANE NEAR 16.2N 64.6W BY THU MORNING. HURRICANE NINE IS THEN FORECAST TO TRACK MORE TO THE NW AS IT CONTINUES TO INTENSIFY REACHING NEAR 17.0N 70.0W FRI MORNING ...TO SW HAITI BY SAT MORNING...AND TO 20.5N 77.5W BY SUN MORNING. WILL CONTINUE TO EMPHASIZE MAINLY THE NRN SEMICIRCLE AS CONTAINING THE MOST HAZARDOUS WIND AND SEA CONDITIONS AS IT TRACKS INTO THE CARIBBEAN...THEN MAKE ADJUSTMENTS LATER ACCORDING TO UPDATED NHC ADVISORIES. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... THE 18 UTC PRELIMINARY SURFACE ANALYSIS SHOWS A 1023 MB HIGH CENTER AT 29N62W WITH A RIDGE SW TO WRN CUBA AND THE FAR SE GULF. BUOYS SHOW SE-S WINDS OF 10-15 KT S OF THE RIDGE...WITH NE-E WINDS OF 10-15 KT S OF 22N E OF THE BAHAMAS AND SW WINDS OF 10-15 KT ARE N OF THE RIDGE. SEAS ARE IN THE 2-3 FT RANGE... EXCEPT 5-6 FT S OF 22N E OF THE BAHAMAS AND 1-2 FT SW OF THE BAHAMAS. THE RIDGE IS FORECAST TO GRADUALLY LIFT N THROUGH SUN AS TROPICAL DEPRESSION NINE MENTIONED ABOVE UNDER TROPICAL N ATLC AND CARIBBEAN TRACKS WNW THROUGH THE PERIOD. LATEST BUOY AND ASCAT DATA FROM THIS AFTERNOON ALREADY SHOW INCREASING NE WINDS IN THE SE PORTION AS A RESULT OF THE TIGHTENING PRES GRADIENT THERE AHEAD OF TROPICAL DEPRESSION NINE. THE DEPRESSION IS FORECAST TO INTENSIFY INTO A STORM TONIGHT NEAR 15.2N 55.3W...AND ONCE IN THE CARIBBEAN SEA INCREASE TO HURRICANE INTENSITY NEAR 16.2N 64.6W BY THU MORNING. THIS FEATURE IS THEN FORECAST TO TRACK NW TO 18.5N 74.0W BY SAT MORNING AND TO JUST S OF CENTRAL CUBA SUN. THE LATTER PART OF THE FORECAST DEPENDS ON JUST WHAT TRANSPIRES WITH THIS FEATURE AS IT CROSSES CUBA AND EMERGES INTO THE FAR SRN WATERS BETWEEN THE CUBA LATER SUN. IMPACTS MAY BE SEEN AS SIGNIFICANTLY BUILDING SEAS AND A SUBSTANTIAL INCREASE IN WINDS OVER MUCH OF THE SW AND WRN WATERS BEGINNING FRI AND LASTING THROUGH DAY 5. WILL ADJUST GRIDS AS FORECAST CONDITIONS CHANGE WITH RESPECT TO TROPICAL DEPRESSION NINE. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA... .TROPICAL STORM WARNING...AMZ023-025-027. NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE