000
AXNT20 KNHC 180532
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST FRI FEB 18 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF 
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE 
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE 
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND 
RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...
THE ITCZ IS ANALYZED FROM W AFRICA NEAR 6N9W 3N17W 2N24W THEN 
ALONG THE EQUATOR BETWEEN 23W-36W THEN S OF THE EQUATOR INTO 
SOUTH AMERICA. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 60 
NM OF LINE FROM 5N10W TO 3N13W. CLUSTERS OF SCATTERED MODERATE 
CONVECTION ARE FROM THE EQUATOR TO 6N BETWEEN 1W-22W. 

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE COVERS THE SE CONUS AND THE GULF ANCHORED BY A 
1029 MB HIGH IN THE W ATLC WITH A WEAK 1024 MB HIGH ALONG THE 
COAST OF FLORIDA NEAR 29N83W. A BROAD UPPER RIDGE AXIS EXTENDS 
FROM W BAY OF CAMPECHE TO LOUISIANA NEAR VERMILION BAY GIVING 
THE GULF NW FLOW ALOFT. STRONG SUBSIDENCE AND DRY STABLE AIR 
DOMINATES THE GULF BASIN LEAVING THE AREA WITH MOSTLY FAIR 
CONDITIONS AGAIN TONIGHT. RETURN FLOW AROUND THE SURFACE RIDGE 
IS GIVING THE W GULF SOUTHERLY FLOW WHICH IS BANKING LOW LEVEL 
CLOUDS OVER THE NW GULF TO INLAND ALONG THE COAST OF MEXICO N 
OF TUXPAN TO OVER TEXAS AND W LOUISIANA. SURFACE RIDGE WILL 
CHANGE LITTLE THROUGH MON. A COLD FRONT MAY APPROACH THE FAR NW 
WATERS LATE MON INTO TUE. 

CARIBBEAN SEA...
REMNANT SURFACE MOISTURE REMAINS ACROSS THE NW CARIBBEAN AND 
CONTINUES TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
WITHIN 90/120 NM OF LINE FROM HISPANIOLA NEAR 19N70W ACROSS 
JAMAICA TO NEAR 17N84W. THE UPPER LEVELS ARE DOMINATED BY AN 
UPPER RIDGE ANCHORED IN THE W TROPICAL ATLC GIVING THE CARIBBEAN 
SW TO W FLOW ALOFT. THIS IS LEAVING THE REMAINDER OF THE 
CARIBBEAN WITH REMARKABLY CLEAR SKIES TONIGHT. THE EXCEPTION IS 
SOME LOW LEVEL CLOUDS WITH ISOLATED SHOWERS BANKING ALONG THE 
MOUNTAINS OF W PANAMA TO SE NICARAGUA AND IN THE SW CARIBBEAN 
WITHIN 90 NM ALONG THE COAST S OF 13N W OF 81W. SURFACE RIDGE 
OVER THE W ATLC WILL DRIFT SLOWLY SE THROUGH SAT. TRADE WINDS 
WILL INCREASE LATE SAT THROUGH MON AS THIS SURFACE RIDGE 
STRENGTHENS.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE W ATLC W OF 45W INTO GULF OF MEXICO 
ANCHORED BY A 1029 MB HIGH NEAR BERMUDA. A BROAD UPPER TROUGH 
COVERS THE N/CENTRAL ATLC WITH A SHORTWAVE UPPER TROUGH AXIS 
EXTENDING INTO THE W ATLC ACROSS BERMUDA SW TO E/CENTRAL CUBA. 
THE BROAD UPPER TROUGH OVER THE CENTRAL ATLC SUPPORTS A 
LINGERING COLD FRONT THAT ENTERS THE E/CENTRAL ATLC NEAR 32N29W 
EXTENDING ALONG 26N39W TO 23N48W WHERE IT BECOMES A SHEAR AXIS 
TO HISPANIOLA NEAR 19N70W. ISOLATED SHOWERS ARE WITHIN 60 NM E 
OF THE FRONT N OF 27N. A BROAD UPPER RIDGE EXTENDS FROM THE W 
TROPICAL ATLC NEAR 8N45W NE TO BEYOND 32N19W. DIFFLUENCE ALOFT 
COUPLED WITH AN UPPER LEVEL JETSTREAM WITH WINDS OF 90 TO 120 KT 
COVERING THE AREA N OF LINE FROM 19N63W TO 25N25W ARE GENERATING 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 300 
NM NW OF THE SHEAR AXIS. A SURFACE RIDGE COVERS THE E ATLC 
ANCHORED BY A 1022 MB HIGH NEAR 30N18W GIVING THE AREA E OF THE 
FRONT FAIR CONDITIONS AGAIN TONIGHT. 

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW