000 AGXX40 KNHC 211837 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 237 PM EDT MON JUL 21 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 BLENDED WITH OFFICIAL. MWW3 AND TAFB NWPS BLENDED WITH OFFICIAL. HIGH CONFIDENCE. AN UPPER TROUGH IS DIGGING EASTWARD ACROSS THE DEEP SOUTH STATES THIS AFTERNOON...SUPPORTING THUNDERSTORMS OVER MUCH OF THE NE GULF. THIS WILL DIMINISH LATE TONIGHT AS THE TROUGH SHIFTS EASTWARD. OTHERWISE A RIDGE REMAINS IN PLACE ACROSS THE GULF OF MEXICO...MAINTAINING LIGHT TO MODERATE WINDS OVER MUCH OF THE BASIN WITH SLIGHT SEAS. THE NORTHERN EXTENT OF A TROPICAL WAVE WILL DRIFT ACROSS THE FAR SW GULF THROUGH MID WEEK...ALLOWING MODERATE TO FRESH E TO SE WINDS OFF THE WEST COAST OF THE YUCATAN PENINSULA BY LATE WED. NO SIGNIFICANT CHANGES THROUGH SATURDAY. NO SIGNIFICANT DIFFERENCES IN MODELS ARE NOTED. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS BLENDED WITH OFFICIAL. MWW3 AND TAFB NWPS BLENDED WITH OFFICIAL IN THE CARIBBEAN...MWW3 BLENDED WITH OFFICIAL IN ATLC. HIGH CONFIDENCE IN CARIBBEAN MODERATE CONFIDENCE IN ATLC. THE MAIN ISSUE FOR THE TROPICAL N ATLC CONTINUES TO BE WEAK LOW PRES EMBEDDED IN THE ITCZ ALONG A TROPICAL WAVE BETWEEN 40W AND 45W. THIS LOW HAS BECOME A LITTLE BETTER ORGANIZED. AN ASCAT SATELLITE PASS FROM EARLIER THIS MORNING UNFORTUNATELY MOSTLY MISSED THE CENTER...BUT STILL INDICATED FRESH TO STRONG WINDS ON THE NORTHERN PORTION OF THE LOW. MODELS ARE NOT REALLY INITIALIZINGTHIS WELL...BUT SHOW SOME DEVELOPMENT OVER THE NEXT COUPLE OF DAYS AS THE LOW/WAVE MOVES THROUGH 50W...FOLLOWED BY A WEAKENING TREND THAT RENDERS AN OPEN WAVE IN THE EASTERN CARIBBEAN BEYOND 72 HOURS. THERE IS SOME UNCERTAINTY IN THE SHORT RANGE HOWEVER AS CONVECTION PERSISTS NEAR THE LOW PRES. TROPICAL CYCLOGENESIS IS POSSIBLE THROUGH 48 HOURS BEFORE THE WEAKENING TREND COMMENCES. GIVEN THE TRENDS IN THE ASCAT SATELLITE PASSES...THE MARINE FORECAST STARTS ABOVE GUIDANCE WITH STRONG WINDS ON THE NORTHERN EXTENT OF THE LOW AND SEAS 8 TO 10 FT. FOR NOW...THIS WILL PERSIST AS THE LOW APPROACHES THE LEEWARDS THROUGH 72 HOURS...THEN WINDS AND SEAS DIMINISH. THIS OF COURSE WILL BE UPGRADED IF THE LOW DEEPENS ANY. IN THE CARIBBEAN...FRESH TO STRONG TRADES PERSIST OVER THE CENTRAL CARIBBEAN...WITH NEAR GALE FORCE WINDS PULSING OFF THE COAST OF COLOMBIA MAINLY IN THE OVERNIGHT AND EARLY MORNING HOURS. THE MAIN ISSUE WILL BE WHETHER OR NOT GALE CONDITIONS ARE LIKELY OFF COLOMBIA. GLOBAL MODELS DO NOT SHOW A STRONG SIGNAL AT THIS TIME. FORECAST FAVORS STRONGER GFS TO CAPTURE 30 KT WINDS OFF COLOMBIA. SEAS WILL BE REACHING 13 FT OFF COLOMBIA ACCORDINGLY. A TROPICAL WAVE WILL DRIFT THROUGH THE CENTRAL CARIBBEAN IN THE WESTERN PORTION OF THE BASIN THROUGH MID WEEK. AN UPPER CYCLONE IS CENTERED OVER HAITI...DELIVERING DRY SUBSIDENT AIR ACROSS THE WESTERN AND CENTRAL CARIBBEAN...BUT ALLOWING FOR SHOWERS AND THUNDERSTORMS OVER THE EASTERN CARIBBEAN. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS BLENDED WITH OFFICIAL. MWW3 AND TAFB NWPS BLENDED WITH OFFICIAL. HIGH CONFIDENCE. THE SUBTROPICAL RIDGE REMAINS IN PLACE N OF 26N THROUGH THE WEEK ALLOWING GENERALLY LIGHT TO MODERATE WINDS OVER MOST OF THE REGION. THIS WILL ALSO SUPPORT FRESH TO OCCASIONALLY STRONG TRADES OFF THE COAST OF HISPANIOLA...MAINLY IN THE OVERNIGHT HOURS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE WARNING TUE NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 CHRISTENSEN. NATIONAL HURRICANE CENTER.