000 AGXX40 KNHC 230754 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 354 AM EDT SAT JUL 23 2016 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: FOR WINDS USED BLEND OF 00Z GFS WITH PREVIOUS OFFICIAL. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. WEAK HIGH PRES RIDGING FROM THE ATLC CONTINUES TO EXTEND WESTWARD ACROSS THE NRN GULF WATERS WHILE AT THE UPPER LEVELS BROAD RIDGING COVERS THE JUST ABOUT THE ENTIRE GULF. A DIFFLUENT FLOW PATTERN ALOFT NOTED OVER THE ERN GULF IN COMBINATION WITH AMPLE DEEP MOISTURE PRESENT THERE IS ALLOWING FOR SCATTERED SHOWERS AND ISOLATED TSTMS TO EXIST OVER MUCH OF THE ERN GULF WATERS. LATEST BUOY OBSERVATIONS AND RECENT ASCAT DATA INDICATE THAT THE PRES GRADIENT OVER THE AREA IS SUPPORTING GENERALLY GENTLE ELY WINDS...EXCEPT FOR THE FAR EASTERN PART OF BAY OF CAMPECHE ALONG THE YUCATAN PENINSULA WHERE WINDS ARE OF MODERATE INTENSITY FROM THE NE-E IN DIRECTION. THE BUOY OBSERVATIONS ALONG WITH RECENT ALTIMETER PASSES SHOW SEAS IN THE 1-3 FT RANGE. LITTLE IN THE WAY OF CHANGES ARE EXPECTED FOR THIS FORECAST PERIOD AS THE RIDGE WILL REMAIN RATHER WEAK THROUGH THE PERIOD WITH INTERMITTENT WEAK 1018-1019 MB HIGH CELLS FORMING ON THE RIDGE IN THE EASTERN GULF NEAR 27N85W. THE NRN EXTENSION OF A TROPICAL WAVE CURRENTLY IN THE WRN CARIBBEAN SEA WILL MOVE THROUGH THE BAY OF CAMPECHE MON THROUGH TUE. SOME SHOWER AND TSTM ACTIVITY CAN BE EXPECTED WITH THE WAVE. OTHERWISE...A THERMAL TROUGH IN THE YUCATAN PENINSULA WILL PUSH OFFSHORE INTO THE SW GULF EACH NIGHT THROUGH THE PERIOD ATTENDANT BY A BRIEF PERIOD OF FRESH N TO NE WINDS AND A SLIGHT INCREASE OF SEAS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: FOR WINDS USED BLEND OF 00Z GFS WITH PREVIOUS OFFICIAL. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 AND NWPS PARAMETERS WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. THE PRES GRADIENT BETWEEN HIGH PRES ACROSS THE CENTRAL ATLC AND LOWER PRES IN NRN PORTIONS OF S AMERICA AND THE SW CARIBBEAN IS MAINTAINING MODERATE TO FRESH TRADE WINDS IN THE CENTRAL CARIBBEAN SEA...AND FRESH TO STRONG WINDS IN THE SOUTH CENTRAL CARIBBEAN SEA. LATEST GLOBAL MODEL GUIDANCE SUGGESTS THAT THERE WILL BE VARIATIONS IN COVERAGE OF THESE STRONGER TRADES DURING THE NEXT FEW DAYS AS WEAKNESSES DEVELOP IN THE ATLC RIDGE. A NARROW SWATH OF STRONG E WINDS WILL DEVELOP JUST S OF HISPANIOLA ON SUN...AND PULSE THROUGH WED. A TROPICAL WAVE WITH AXIS ALONG 81W S OF 21N IS MOVING W AT 10-15 KT. LATEST SATELLITE IMAGERY SHOWS THAT DEEP LAYER MOISTURE HAS SIGNIFICANTLY INCREASED SINCE 24 HRS AGO TO THE W OF THE WAVE MAINLY ATTRIBUTED TO THE EXISTENCE OF AN UPPER LEVEL TROUGH SITUATED ACROSS THE NW CARIBBEAN SEA. SCATTERED SHOWERS AND TSTMS ARE NOTED S OF 21N BETWEEN THE WAVE AND 84W. THIS ACTIVITY IS CAPABLE OF PRODUCING FREQUENT LIGHTNING STRIKES AND GUSTY WINDS. THE WAVE IS FORECAST TO REACH NEAR 85W EARLY TONIGHT...THEN MOVE INLAND ACROSS CENTRAL AMERICA ON SUN. ANOTHER TROPICAL WAVE...CURRENTLY WELL E OF THE TROPICAL N ATLC ZONES IN THE E ATLC...IS FORECAST TO ENTER THE ERN PORTION OF THE TROPICAL N ATLC LATE MON NIGHT...AND MOVE THROUGH THE REST OF THE TROPICAL N ATLC THROUGH TUE NIGHT AND THE ENTER THE ERN CARIBBEAN ON WED. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: FOR WINDS USED BLEND OF 00Z GFS WITH PREVIOUS OFFICIAL. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. A SURFACE TROUGH EXTENDS FROM NEAR 30N72W TO THE NW BAHAMAS 28N72W...WHILE WEAK HIGH PRES IS PRESENT ELSEWHERE. A DIFFLUENT FLOW PATTERN SEEN TO THE E OF AN ELONGATED UPPER LOW FEATURE OVER THE NW PART OF THE BASIN IS HELPING TO SUPPORT SCATTERED TO NUMEROUS TSTM ACTIVITY OVER MUCH OF THE BAHAMAS AS WELL AS OVER JUST ABOUT THE ENTIRE ZONE AMZ119...AND THE WRN PART OF ZONE AMZ115. THE SURFACE TROUGH IS FORECAST DRIFT WESTWARD AND GRADUALLY WEAKEN THROUGH SUN NIGHT. THE SHOWER AND TSTM ACTIVITY SHOULD PERSIST THROUGH THE WEEKEND BEFORE DIMINISHING. LATEST SYNOPTIC ANALYSIS REVEALS A RATHER WEAK PRES GRADIENT THROUGHOUT WITH LIGHT TO GENTLE E-SE WINDS ACROSS MUCH OF THE BASIN...EXCEPT FOR THE NE PORTION WHERE WINDS ARE LIGHT MAINLY S- SW IN DIRECTION. BOTH BUOY AND ALTIMETER DATA SHOW SEAS IN THE RANGE OF 4-5 FT E OF THE BAHAMAS...AND 1-2 FT SW OF THE BAHAMAS...AND ALSO N OF 27N W OF 81W. A SMALL POCKET OF SEAS IN THE 5-6 FT RANGE ARE NOTED BETWEEN THE SE BAHAMAS AND HISPANIOLA. THE SEAS E OF THE BAHAMAS ARE FORECAST TO SUBSIDE SLIGHTLY N OF ABOUT 25N THROUGH MON. THE AFOREMENTIONED UPPER LOW IS FORECAST TO MOVE SW ACROSS THE NW BAHAMAS TODAY AND TONIGHT...THEN WEAKEN AS IT MOVES ACROSS S FL SUN AND TO THE ERN GULF OF MEXICO SUN NIGHT AND MON. MID/UPPER LEVEL RIDGING WILL REPLACE THE LOW OVER THE NW AND N CENTRAL SECTIONS OF THE BASIN. AT THE SURFACE...RIDGING WILL SET UP ROUGHLY ALONG A PSN FROM 29N69W NW TO NE FL BY TUE NIGHT. THE FLOW PATTERN S OF THE RIDGE WILL BECOME E-SE WITH WINDS IN THE GENTLE TO MODERATE RANGE...EXCEPT FOR THE STRONGER PULSING E WINDS TO THE STRONG CATEGORY BETWEEN THE BAHAMAS AND HISPANIOLA. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS II COLLABORATION CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.