000 AGXX40 KNHC 310810 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 410 AM EDT THU JUL 31 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 WEAK FRONTAL BOUNDARY HAS SHIFTED SLOWLY S ACROSS E PORTIONS OF GULF PAST 6-8 HOURS...NOW EXTENDING FROM JUST N OF NAPLES...SW TO NEAR 24.5N86W THEN NW TO UPPER TEXAS COASTAL WATERS...WITH BROAD AND WEAK CYCLONIC FLOW ABOUT THE BOUNDARY E OF 90W...AND YIELDING W-SW WINDS ACROSS THE W STRAITS AND INTO THE KEYS ATTM. BOUNDARY TO DRIFT SSE TODAY ACROSS SE PORTIONS...THEN BEGIN TO DRIFT BACK TOWARDS THE NW FRI AND SAT AND GRADUALLY DISSIPATE. NW ATLC RIDGE TO SHIFT NW AND BUILD MODESTLY ACROSS NW PORTIONS OF SW N ATLC AND TO E COAST OF FLORIDA THU NIGHT AND FRI...AIDING FRONTAL MOVEMENT...WITH WEAK HIGH PREVAILING BETWEEN MOUTH OF MS AND BIG BEND REGION...YIELDING LIGHT TO MODERATE ANTICYCLONIC FLOW ACROSS THE BASIN. MODERATE S TO SE WINDS ACROSS UPPER MEXICAN AND TEXAS COASTAL WATERS LIKELY TO BECOME ENHANCED BY DIURNAL HEATING EACH AFTERNOON AND REACH 15-20 KT FOR A FEW HOURS...INCREASING SEAS LOCALLY TO 4 FT...AND VERY ISOLATED SPOTS TO 5 FT. LIKEWISE... LATE AFTERNOON/EVENING THERMAL TROUGH ALSO EXPECTED TO YIELD NEAR 20 KT WINDS OFF NW AND W COASTS OF YUCATAN EACH DAY...YIELDING SEAS PEAKING BRIEFLY AT 3-5 FT EACH DAY. OTHERWISE...TRANQUIL CONDITIONS EXPECTED THROUGH THE WEEKEND. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS-ECMWF CONSENSUS GFS AND ECMWF HAVE COME IN VERY GOOD AGREEMENT IN ASSOCIATION WITH TROPICAL LOW NEAR 50W ATTM...AND ASSOCIATED CONDITIONS AS THE LOW MOVES ACROSS THE LEEWARDS...THE VIRGIN ISLANDS...AND PORTIONS OF PUERTO RICO 36-72 HRS. FRESH TRADE PRESENTLY PREVAIL IN NORMAL POSITION OF CARIB JET...OFF COAST OF COLOMBIA...AND EXPECTED TO PEAK AROUND 25 KT THIS MORNING...WITH SEAS 8-10 FT. OTHERWISE...BROAD AND WEAKLY CYCLONIC TURNING OCCURRING IN WIND FIELD ACROSS THE BASIN ATTM...WITH MODERATE TO FRESH TRADES AND SEAS LESS THAN 8 FT...EXCEPT OFFSHORE WATERS N OF PANAMA. NO SIGNIFICANT CHANGES EXPECTED WITH THESE CONDITIONS THROUGH FRI... EVEN AS TROPICAL LOW APPROACHES LEEWARDS AND MOVES ACROSS PORTIONS OF NE CARIB FRI NIGHT THROUGH SAT NIGHT. RIDGING BEHIND EXITING LOW TO THE NW LATE SAT AND SUN WILL EXPAND FRESH TRADES SIGNIFICANTLY ACROSS THE BASIN E OF 80W...IN ASSOCIATION WITH NEXT TROPICAL WAVE APPROACHING LESSER ANTILLES SUN NIGHT. TROPICAL LOW ALONG 50W THIS MORNING STILL STRUGGLING AGAINST DRY AIR INTRUSION ACROSS MOST OF N SEMICIRCLE...WHICH IS FINALLY MORE OBVIOUS BASED ON GOES-R PROVING GROUND IMAGERY AND CIMSS SAL PRODUCTS. GLOBAL MODELS SUGGEST THERE IS AN OPPORTUNITY FOR BEST MOISTURE CURRENTLY ACROSS SE SEMICIRCLE OF SYSTEM TO WRAP UP AROUND LOW FRI AND FRI NIGHT AS LOW APPROACHES AND THEN REACHES LEEWARDS...AND THIS MAY BE THE WINDOW OF OPPORTUNITY FOR TROPICAL CYCLONE FORMATION. MODELS ALSO SUGGEST CONVECTIVE PATTERN TO SHIFT FROM ACROSS E AND NE PORTIONS AS SYSTEM MOVES ACROSS LEEWARDS...VIRGIN ISLANDS...AND PUERTO RICO FRI NIGHT THROUGH SUN AND COULD REDUCE RAINFALL POTENTIAL FOR VIRGIN ISLANDS AND P.R. WHERE RAIN IS NEEDED. GFS AND ECMWF CURRENTLY IN EXCELLENT AGREEMENT THROUGH 72 HOURS AND CONFIDENCE IN FORECAST HAS INCREASED SIGNIFICANTLY. GALE WARNING MAY BE NEEDED ACROSS NE SEMICIRCLE 36-72 HRS IF CONVECTION DOES NOT INCREASE ABOUT SYSTEM...WITH ASSOCIATED SEAS OF 12-15 FT MOVING THROUGH NEAR AND OFFSHORE COASTAL WATERS OF LEEWARDS AND NE CARIB ISLANDS DURING THIS TIME FRAME. NEW 06Z RUN OF NWPS SHOULD REFLECT THESE VALUES. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: ECMWF-GFS CONSENSUS WEAK FRONTAL BOUNDARY ACROSS FAR NW PORTIONS HAS ALREADY STALLED AND WILL DRIFT BACK TOWARD THE NW LATER TODAY AND TONIGHT AND INLAND ACROSS SE U.S. AND FLORIDA BY 36 HOURS. RIDGING CONTINUES FROM NW ATLC...SW TO CENTRAL BAHAMAS AND STRAITS OF FL ALONG 80W...AND WILL SHIFT SLIGHTLY NW NEXT FEW DAYS AS DEEP LAYERED LOW ACROSS CENTRAL ATLC DIGS SW AND FORCES WEAK RIDGE SLIGHTLY NW ACROSS THE W AND SW N ATLC. MODERATE SE TRADES CURRENTLY FROM SE WATERS INTO TURKS AND CAICOS WILL SPREAD SLIGHTLY NW THROUGH FRI AND INTO CENTRAL BAHAMAS AND ATLC WATERS TO THE E...INCREASING SEAS TO 4-5 FT. TROPICAL LOW... EXPECTED TO EXIT ATLC COASTAL WATERS OF PUERTO RICO SAT EVENING-SAT NIGHT AND CONTINUE ALONG A NW COARSE THROUGH SE WATERS. WHILE GLOBAL MODELS SUGGEST SLOW WEAKENING SUN THROUGH MON...DYNAMIC FETCH OF NE SEMICIRCLE OF LOW WILL MAINTAIN SEAS 10-12 FT LIKELY THROUGH MON AFTERNOON IN THIS SEMICIRCLE BEFORE GRADUALLY DIMINISHING INTO TUE. RIDGING BEHIND THE LOW WILL COMBINE WITH NEXT TROPICAL WAVE TO REACH THE LESSER ANTILLES MON-TUE FOR FRESH TO STRONG TRADES ACROSS SE WATERS AND SPREADING NW IN WAKE OF TROPICAL LOW PASSING JUST E OF CENTRAL AND NW BAHAMAS. AGAIN...CONFIDENCE IN FORECAST HAS INCREASED WITH GLOBAL MODELS IN GOOD AGREEMENT THROUGH DAY 5...AND CONTINUE TO FORECAST RECURVATURE TOWARD THE NNW DAY 4 AND 5. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 STRIPLING. NATIONAL HURRICANE CENTER.