000
AXNT20 KNHC 170540
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST THU FEB 17 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 8N11W ALONG 3N16W 1N25W 
THEN S OF THE EQUATOR NEAR 34W. CLUSTERS OF SCATTERED MODERATE/ 
ISOLATED STRONG CONVECTION ARE FROM 5N TO S OF THE EQUATOR 
BETWEEN THE PRIME MERIDIAN AND 32W. 

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE COVERS THE E HALF OF THE CONUS AND THE GULF 
ANCHORED BY A 1029 MB HIGH IN THE W ATLC. A BROAD UPPER RIDGE 
EXTENDS ALONG THE COAST OF MEXICO TO OVER TEXAS COVERING THE W 
GULF WHILE AN UPPER TROUGH REMAINS OVER THE E GULF CONTINUING TO 
MOVE INTO THE W ATLC GIVING THE GULF W TO NW FLOW ALOFT. STRONG 
SUBSIDENCE AND DRY STABLE AIR DOMINATES THE GULF BASIN LEAVING 
THE AREA WITH MOSTLY FAIR CONDITIONS TONIGHT. RETURN FLOW AROUND 
THE SURFACE RIDGE IS GIVING THE TEXAS COAST SOUTHERLY FLOW WHICH 
IS BANKING LOW LEVEL CLOUDS TO INLAND OVER TEXAS. HIGH PRESSURE 
WILL REMAIN IN CONTROL OF THE GULF THOUGH THE WEEKEND. 

CARIBBEAN SEA...
THE REMNANT SURFACE MOISTURE REMAINS OVER THE NW CARIBBEAN FROM 
THE RECENT FRONTAL PASSAGE AND CONTINUES TO GENERATE SCATTERED 
SHOWERS/ISOLATED THUNDERSTORMS MAINLY FROM 14N-18N W OF 81W TO 
INLAND OVER CENTRAL AMERICA. 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 FAIR CONDITIONS AGAIN TONIGHT WITH SOME 
ISOLATED SHOWERS USHERED IN ON FRESH TO MODERATE TRADE WINDS. 
THE RIDGE OVER THE W ATLC WILL WEAKEN LATER TODAY RESULTING IN 
DIMINISHED TRADE WINDS OVER THE E CARIBBEAN. TRADE WINDS WILL 
INCREASE AGAIN FRI NIGHT THROUGH THE WEEKEND AS THE RIDGE 
RE-STRENGTHENS.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE W ATLC W OF 65W INTO GULF OF MEXICO 
ANCHORED BY A 1029 MB HIGH ABOUT 200 NM WNW OF BERMUDA. A BROAD 
UPPER TROUGH COVERS THE W ATLC INTO THE CENTRAL ATLC W OF 40W 
SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N41W 
EXPENDING TO 24N56W WHERE TI BECOMES A SHEAR AXIS TO THE COAST 
OF HISPANIOLA NEAR THE HAITI/DOMINICAN REPUBLIC BORDER. 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 
90 NM E OF THE FRONT AND ISOLATED SHOWERS WITHIN 90 NM EITHER 
SIDE OF THE SHEAR AXIS. A SURFACE RIDGE COVERS THE REMAINDER OF 
THE CENTRAL ATLC INTO THE E ATLC ANCHORED BY A 1027 MB HIGH NEAR 
29N26W GIVING THE AREA E OF THE FRONT FAIR CONDITIONS TONIGHT. 

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

$$
PAW