Marine Weather Discussion

000
AGXX40 KNHC 262023 CCA
MIMATS

MARINE WEATHER DISCUSSION...CORRECTED  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EST THU NOV 26 2009

CORRECTED ISSUANCE TIME

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

GULF OF MEXICO...
THE SLOW MOVING FRONTAL BOUNDARY CURRENTLY PUSHING THROUGH THE 
STRAITS OF FL AND YUCATAN CHANNEL WILL FINALLY MOVE SE OF THE 
GULF TONIGHT. SURFACE OBSERVATIONS AND THE 1600 UTC ASCAT PASS 
SHOW 20 KT WINDS OVER MUCH OF THE GULF...WITH THE STRONGEST 
WINDS WITHIN 120 NM N OF THE FRONT OVER THE CENTRAL GULF. RECENT 
SHIP OBSERVATIONS SHOW SIGNIFICANT WAVE HEIGHT HAVE BUILT TO THE 
10 TO 14 FT RANGE HERE AS WELL. NORTHERLY FLOW IN THE SW 
GULF...WHICH HAD BEEN IN THE 25 TO 30 KT RANGE OVERNIGHT...WILL 
DIMINISH OVER THE NEXT 24 HOUR AND SHIFT EASTERLY AS THE HIGH 
PRES RIDGE OVER THE WESTERN GULF SHIFTS TO THE 
NORTHEAST....REACHING NORTH FLORIDA LATE SAT WITH RIDGE OVER THE 
NORTHEAST GULF OF MEXICO SUN. RIDGE WILL WEAKEN MON AS A COLD 
FRONT MOVES OFF THE TEXAS COAST. THE MODELS ARE IN GOOD 
AGREEMENT UNTIL THIS POINT WHEN THE GFS...UKMET...AND CMC CARRY 
A WEAK SURFACE LOW THROUGH THE NORTHERN GULF MON NIGHT AND DRAG 
THE FRONT EASTWARD FASTER THAN THE NOGAPS AND ECMWF. DESPITE 
THESE DIFFERENCES...THE MODELS ARE COMING INTO BETTER AGREEMENT 
HERE...TRENDING TOWARD A SLOWER SOLUTION HERE MORE LIKE THE 
ECMWF.

CARIBBEAN AND TROPICAL N ATLC...
THE SLOW MOVING FRONTAL BOUNDARY CURRENTLY OVER THE FAR NW 
CARIBBEAN IS BRINGING 20 KT N FLOW INTO THE GULF OF HONDURAS 
BEHIND THE FRONT ACCORDING TO THE 1600 UTC ASCAT PASS. THE FRONT 
IS FORECAST TO CONTINUE TO SLOWLY SHIFT EASTWARD OVER THE NEXT 
FEW DAYS AND DISSIPATE. THE MODELS ARE IN REASONABLE AGREEMENT 
ON WINDS AND SEAS DIMINISHING BELOW 20 KT/8 FT BY SUN. 
THEN...LOOK FOR WINDS TO SHIFT MORE SOUTHERLY IN ADVANCE OF THE 
STRONG COLD FRONT IN THE GULF OF MEXICO EARLY NEXT WEEK. FARTHER 
SOUTH...THE PRES GRADIENT BETWEEN THE 1017 MB HIGH NEAR 26N62W 
AND THE 1005 MB COLOMBIAN LOW CONTINUES TO SUPPORT WINDS IN THE 
25-30 KT RANGE AS SEEN IN SHIP OBSERVATIONS FROM SHIP DHER AND 
AND 9HXD9 OVER THE PAST FEW HOURS.  HIGH PRES TO THE NORTH WILL 
BE FORCED E AS THE COLD FRONT OVER THE SW N ATLC ZONE PUSHES 
EASTWARD...DECREASING THE PRES GRADIENT AND THE WINDS OVER THE 
CENTRAL CARIBBEAN INTO SAT...BUT LOOK FOR WINDS TO BUILD AGAIN 
BY SUN AS NEW HIGH PRES MOVES IN BEHIND THE SW N ATLC COLD 
FRONT. THIS HIGH PRES WILL BE CHASED E EARLY NEXT WEEK BY THE 
COLD FRONT ADVANCING THROUGH THE GULF OF MEXICO. FARTHER E OVER 
THE TROPICAL ATLC...A SLOW MOVING DEEP LAYER TROUGH ALONG 50-55W 
WILL CONTINUE TO SUPPORT A WEAK SURFACE TROUGH S OF 20N INTO THE 
WEEKEND...AND TRADE WINDS OVER 20 KT AND MUCH OF THE CONVECTION 
ASSOCIATED WITH THE SYSTEM WILL MAINLY BE CONFINED E OF THIS 
TROUGH KEEPING CONDITIONS RELATIVELY TRANQUIL OVER THE LESSER 
ANTILLES THROUGH THE WEEKEND. THE WEAK FRONTAL BOUNDARY 
ASSOCIATED WITH THE FRONT CURRENTLY OVER THE SW N ATLC WILL 
APPROACH THE NE CARIBBEAN ISLANDS EARLY NEXT WEEK AND MAY 
ENHANCE THE CHANCE OF CONVECTION.

SW N ATLC...
NEITHER THE 1500 UTC SREF OR 1200 UTC GEFS MEMBERS SUPPORT WINDS 
TO GALE FORCE NEAR THE FRONT PASSING THROUGH THE SW N ATLC FRI 
AND SAT...BUT THE DETERMINISTIC RUNS GENERALLY SUPPORT WINDS TO 
30 KT HERE IN THE SOUTHERLY FLOW AHEAD OF THE FRONT. THE 1420 
UTC ASCAT PASS ALREADY SHOWS SOUTHERLY FLOW IN THE 20-25 KT 
RANGE OVER N CENTRAL WATERS. ONCE THE UPPER LEVEL TROUGH CATCHES 
UP TO THIS SURFACE BOUNDARY...LOOK FOR THE FRONT TO PICK UP 
SPEED...MOVING THROUGH THE REMAINDER OF THE SW N ATLC ZONE BY 
SAT NIGHT. THE MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE 
PASSAGE OF THIS FRONTAL SYSTEM THROUGH THE ZONE AS WELL AS WITH 
THE TIMING AND TRACK OF THE HIGH PRES SYSTEM IN ITS WAKE. 
DIFFERENCES ARISE WITH THE TIMING OF THE NEXT COLD FRONT MOVING 
INTO NW WATERS TUE...WITH THE GFS AND ECMWF PREFERRING A SLOWER 
SOLUTION THAN THE OTHER MODELS. THE ECMWF IS PREFERRED IN THE 
GULF AS EXPLAINED IN THE FIRST SECTION ABOVE.

OTHERWISE WINDS WILL BE LESS THAN 20 KT.

WARNINGS...

ATLC...
.NONE.

CARIBBEAN...
.NONE.

GULF OF MEXICO...
.NONE.

$$
FORECASTER SCHAUER