000
AGXX40 KNHC 240800 CCA
MIMATS

MARINE WEATHER DISCUSSION...CORRECTION         
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
300 AM EDT FRI APR 24 2009

.COR TO ISSUANCE DATE/TIME...
 
MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND 
SOUTHWEST NORTH ATLC S OF 31N W OF 55W.

GULF OF MEXICO...
FLAT UPPER RIDGE PREVAILS ACROSS THE S HALF OF THE GULF THIS 
MORNING...WHILE A SLOW MOVING S/W AND ASSOCIATED LOW WAS 
PROGRESSING INTO W AND SW TEXAS AND DRAGGING ALONG NRN MEXICO. 
THIS FEATURE IS FORECAST TO MOVE ACROSS THE NRN GULF STATES 
DURING THE NEXT FEW DAYS AND WILL INITIATE SOME CONVECTION ALONG 
COASTAL SECTIONS...BUT WILL HAVE LIMITED IMPACT ON THE WEATHER 
OVER THE BROADER GULF. A 1026 MB SURFACE HIGH NEAR 29N72W 
OVERNIGHT IS FORECAST TO SHIFT SLIGHTLY N DURING THE NEXT FEW 
DAYS AND STRENGTHEN SOMEWHAT...WHILE THE ATLC RIDGE REMAINS 
GENERALLY IN PLACE. RIDGING FROM THIS W ATLC HIGH WILL MAINTAIN 
AN E TO SE FLOW ACROSS THE GULF FOR THE NEXT SEVERAL DAYS...WITH 
MILD WINDS AND SEAS ACROSS THE NE AND EXTREME N GULF...WHILE 
15-25 KT FLOW DOMINATES ELSEWHERE. SEAS ARE EXPECTED TO BUILD 
8-9 FT IN THE NW GULF FRI NIGHT...AND THEN 8-10 BY SUN NIGHT. 
CONDITIONS INVOF OF THE FLORIDA STRAITS COULD BECOME VERY ROUGH 
AND DANGEROUS AS A PERSISTENT 20-25 KT FLOW WITH PERIODS OF 30 
KT WILL FLOW DIRECTLY AGAINST THE W TO E CURRENT N OF CUBA...AND 
COULD INDUCE STEEP WAVES OF 12 FT AND GREATER. WAVE MODELS DO 
NOT HANDLE THIS TYPE OF SITUATION WELL AT ALL.
 
SW N ATLC...
A DEEP LAYER L/W TROUGH SUPPORTS A WEAK COLD FRONT EXTENDING 
FROM SE OF BERMUDA...SW TO A FRONTAL WAVE NEAR 24N71W THEN 
THROUGH THE TURKS AND CAICOS ISLES. LLVL CONVERGENCE INVOF OF 
THE FRONTAL BOUNDARY...AND LIFT AND UPPER DIVERGENCE OCCURRING 
JUST AHEAD WILL MAINTAIN SCATTERED SHOWERS AND ISOLATED TSTORMS 
ALONG AND AHEAD OF THE FRONTAL BOUNDARY N OF 23N DURING THE NEXT 
24 HOURS...GRADUALLY SHIFTING NE THROUGH SAT. SUBSIDENCE AND 
FAIR WEATHER WILL PREVAIL TO THE W OF THIS BOUNDARY AS HIGH 
PRESSURE EXPANDS DURING THE WEEKEND AND PERSISTS INTO NEXT WEEK. 
EVENING QUIKSCAT PASS SHOWED A ZONE OF 20-25 KT NE WINDS ALONG 
AND UP TO 225 NM BEHIND THIS BOUNDARY...SPREADING THROUGH THE 
SRN BAHAMAS AND THEN THROUGH THE FLORIDA STRAITS. SEAS TO THE E 
OF THE BAHAMAS WERE BUILDING TO 7 FT IN MODERATE PERIOD WIND 
SWELL AND ARE EXPECTED TO BUILD FURTHER TO 9-10 FT THROUGH THE 
WEEKEND...WITH THE ANTICYCLONIC FLOW BEHIND THE WEAKENING 
BOUNDARY EXPECTED TO YIELD A BROAD ZONE OF 6-8 FT ACROSS MUCH OF 
THE OFFSHORE SW ATLC WATERS...WHICH WILL PUSH THROUGH THE 
CARIBBEAN PASSAGES.

CARIBBEAN AND TROPICAL N ATLC...
A MODEST PRESSURE GRADIENT WILL PREVAIL FOR THE NEXT SEVERAL 
DAYS...BETWEEN THE BUILDING RIDGE ACROSS THE W ATLC AND 
PREVAILING LOW PRES OVER COLOMBIA. THIS WILL DRIVE THE TRADES TO 
NEAR 30 KT ALONG COAST OF COLOMBIA...WITH EXPANDING COVERAGE OF 
20-25 KT ACROSS THE EASTERN CARIBBEAN. THE TROPICAL ATLC WILL 
ALSO REMAIN UNDER FRESH TO STRONG TRADES E OF ISLANDS...WITH THE 
ERN LIMB OF THE ATLC HIGH PRES RIDGE PRODUCING A LONG FETCH 
AIMED AT THE AREA...BUILDING NELY SWELLS 8 TO 10 FT BY SUNDAY. 
SHALLOW MOISTURE IN PATCHY STRATOCU WILL PRODUCE SCATTERED 
PASSING SHOWERS ACROSS THE NE AND E CARIB NEXT 24 HOURS.

ATLC...
.NONE.. 

CARIBBEAN...
.NONE.

GULF OF MEXICO...
.NONE.

FORECASTER STRIPLING. TROPICAL PREDICTION CENTER.