000
AGXX40 KNHC 241756
MIMATS

MARINE WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT TUE JUL 24 2012

MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA
AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W.

GULF OF MEXICO...
THE WESTERN EXTENSION OF THE ATLC SUBTROPICAL RIDGE EXTENDS FROM 
CENTRAL FL TO THE NE TX COAST WITH A WEAKENING SURFACE TROUGH NE 
OF THE RIDGE AND EXTENDING FROM FL PANHANDLE SW TO NEAR 26N87W. 
THE RIDGE WILL SHIFT S TODAY AND EXTEND ACROSS S FL...BUT STILL 
EXTEND NW TO THE TX/LA BORDER. WEAK TROUGHING WILL DEVELOP 
INTERMITTENTLY OVER THE EASTERN WATERS EFFECTIVELY CUTTING OFF 
THE GULF OF MEXICO RIDGE SEGMENT FROM THE PARENT ATLC SEGMENT... 
WITH A SURFACE HIGH OF ABOUT 1020 MB DEVELOPING OVER THE CENTRAL 
PORTION ALONG THE RIDGE AXIS. THE E SEGMENT OF THE RIDGE WILL 
SHIFT SLOWLY N OVER THE WEEKEND. SLY RETURN FLOW WILL INCREASE 
TO 15-20 KT ALONG THE W PERIPHERY OF THE RIDGE ACROSS THE W 
CENTRAL WATERS ON WED AND CONTINUE THROUGH THU NIGHT...THEN THE 
GRADIENT WILL RELAX SOME. THE EVENING ENHANCEMENT OF NE WINDS TO 
15-20 KT ALONG THE NW YUCATAN PENINSULA WILL CONTINUE THIS 
EVENING AND WED WITH THE GRADIENT STRENGTHENED LATE THU THROUGH 
EARLY FRI AS THE NORTHERN PORTION OF A TROPICAL WAVE PASSES 
THROUGH THE BAY OF CAMPECHE. ECMWF AND GFS IN CLOSE AGREEMENT... 
THUS BLENDED A PERCENTAGE OF EACH WITH PREVIOUS PACKAGE.   

SW N ATLC S OF 31N W OF 65W...
THE SUBTROPICAL RIDGE EXTENDING FROM 25N55W TO CENTRAL FL WILL 
SHIFT S ON WED EXTENDING FROM 25N55W TO SE FL WITH LITTLE CHANGE 
THROUGH FRI. THE RIDGE SHIFTS N AGAIN ON FRI NIGHT REACHING 
ALONG 28N55W TO 27N80W. AS THE RIDGE SHIFTS S ON WED A COLD 
FRONT PASSES THROUGH ATLC OFFSHORE ZONES AMZ113 AND AMZ115 WITH 
SW-W WINDS INCREASING 20-25 KT THEN CLOCKING TO NW OVER THE 
WATERS N OF 30.5N WHILE DIMINISHING TO ABOUT 10 KT. MODERATE TO 
FRESH TRADE WINDS WILL CONTINUE ACROSS WATERS S OF 23N THROUGH 
THE PERIOD. BLENDED PERCENTAGE OF GFS AND ECMWF WITH PREVIOUS 
FORECAST.

CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W...
HIGH PRES RIDGE N OF THE AREA WILL CONTINUE TO MAINTAIN 
FRESH-STRONG NE-E WINDS ACROSS THE AREA BETWEEN 68-82W THROUGH 
THU NIGHT. THE LATEST GFS RUN FURTHER STRENGTHENS THE TRADES 
ALONG THE NW COAST OF COLOMBIA EARLY FRI HINTING AT MINIMAL  
GALE FORCE. MAINTAINED ENE WINDS AT 30 KT MAX IN GRAPHIC PACKAGE 
AS LATEST GFS REVERSED FROM A WEAKENING TO A STRENGTHENING TREND 
AND OTHER GLOBAL GUIDANCE IS NOT AS AGGRESSIVE. A TROPICAL WAVE 
IN THE THE CENTRAL CARIBBEAN WILL CONTINUE W THROUGH THE W 
CARIBBEAN THROUGH LATE WED MOVE W OF THE AREA EARLY FRI THU. A 
SECOND WAVE IN THE E CARIBBEAN NEAR 65W WILL MOVE THROUGH THE 
CENTRAL PORTION WED-THU...AND THE W CARIBBEAN FRI-SAT. A 
TROPICAL WAVE WELL E OF THE AREA WILL REACH ALONG 35W 
FRI...ALONG 40W SAT...AND 45W SUN WITH THE GFS SUGGESTING LOW 
PRES DEVELOPMENT TO OCCUR AT ABOUT 12.5N ALONG THE WAVE AXIS 
WITH THE LOW TRACKING WNW REACHING NEAR ABOUT 14N45W SUN. 
BLENDED GFS AND ECMWF WITH PREVIOUS FORECAST.

NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT 
WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE

GULF OF MEXICO...
.NONE.

CARIBBEAN SEA...
.NONE.

SW N ATLANTIC...
.NONE.
    
FOR ADDITIONAL INFORMATION PLEASE VISIT
WWW.HURRICANES.GOV/MARINE

$$
FORECASTER NELSON