000
AXNT20 KNHC 200543
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST SUN FEB 20 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 SW AFRICA NEAR 7N11W 3N28W ALONG THE 
EQUATOR W OF 44W TO INLAND OVER SOUTH AMERICA. SCATTERED 
MODERATE/STRONG CONVECTION IS 2N TO THE EQUATOR BETWEEN 6W-9W. 
SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA 
WITHIN 75 NM OF THE ITCZ BETWEEN 17W-36W. 

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE COVERS THE GULF INTO THE ATLC ANCHORED BY A 1023 
MB HIGH S OF PENSACOLA FLORIDA NEAR 29N87W. BROAD UPPER RIDGE 
COVERS THE GULF WITH THE AXIS EXTENDING FROM THE BAY OF CAMPECHE 
TO OVER THE N GULF COAST OVER SE LOUISIANA WITH WATER VAPOR 
IMAGERY INDICATING MODERATE TO STRONG SUBSIDENCE ACROSS THE 
ENTIRE GULF BASIN PROVIDING CLEAR SKIES OVER MOST OF THE GULF 
AGAIN TONIGHT. THE EXCEPTION IS OVER OF THE NW GULF WHERE 
PATCHES OF SCATTERED LOW CLOUDS AND FOG ARE N OF 28N W OF 89W TO 
INLAND OVER LOUISIANA AND TEXAS AND OVER THE W GULF W OF 95W TO 
INLAND OVER MEXICO N OF VERACRUZ AND THE REMAINDER OF THE TEXAS. 
THE HIGH PRESSURE IS EXPECTED TO DISSIPATE LATER TODAY. A WEAK 
COLD FRONT IS EXPECTED TO MOVE INTO THE GULF TUE THEN BECOME 
STATIONARY LATE TUE AND DISSIPATE WED.  

CARIBBEAN SEA...
AN UPPER TROUGH EXTENDING FROM THE W/CENTRAL ATLC COVERS THE N 
CARIBBEAN FROM CUBA TO THE LEEWARD ISLANDS. WATER VAPOR IMAGERY 
INDICATES VERY STRONG SUBSIDENCE ALOFT COVERING THE CARIBBEAN 
GIVING THE AREA MOSTLY CLEAR SKIES AGAIN TONIGHT. FRESH EASTERLY 
TRADE WINDS CONTINUE ACROSS THE CARIBBEAN USHERING SOME PATCHES 
OF ISOLATED SHOWERS ACROSS THE ENTIRE BASIN. HIGH PRESSURE OVER 
THE W ATLC WILL MOVE SE AND WEAKEN THROUGH SUN NIGHT. NEW HIGH 
BUILDS N OF THE AREA MON THROUGH WED ALLOWING FOR TRADES TO 
INCREASE. 

ATLANTIC OCEAN...
A SURFACE RIDGE THAT COVERS THE GULF OF MEXICO EXTENDS OVER THE 
FAR W ATLC W OF 75W. AN UPPER TROUGH HAS MOVED S TO OVER THE W 
ATLC SUPPORTING A COLD FRONT THAT ENTERS THE REGION THROUGH 
32N61W TO 29N72W. HOWEVER...WATER VAPOR IMAGERY INDICATES 
MODERATE TO STRONG SUBSIDENCE ACROSS THE W ATLC LIMITING ANY 
SHOWER ACTIVITY. A BROAD UPPER LEVEL TROUGH DOMINATES THE 
REMAINDER OF THE W AND CENTRAL ATLC W OF 40W WITH THE AXIS 
EXTENDING THROUGH 32N40W 26N54W OVER THE GREATER ANTILLES INTO 
THE N CARIBBEAN. A WEAK SURFACE TROUGH IS BENEATH THE UPPER 
TROUGH EXTENDING FROM NEAR 28N34W TO 25N39W. A BROAD UPPER RIDGE 
COVERS THE REMAINDER OF THE CENTRAL AND INTO E ATLC WITH THE 
MEAN AXIS ALONG 20W. A JET STREAM WITH WINDS OF 90 TO 110 KT IS 
RIDING N ALONG THE W PORTION OF THE UPPER RIDGE WITHIN 150/200 
NM OF LINE FROM 20N50W 28N29W TO 30N11W. SCATTERED SHOWER ARE N 
OF 28N BETWEEN 26W-38W. A NEAR STATIONARY UPPER LEVEL LOW IS 
UNDERCUTTING THE UPPER RIDGE LOCATED JUST S OF THE CAPE VERDE 
ISLANDS. HOWEVER... WATER VAPOR IMAGERY INDICATES STRONG 
SUBSIDENCE ALOFT FROM 10N-23N E OF 35W LIMITING ANY SHOWER 
ACTIVITY IN THE AREA. A SURFACE RIDGE IS AGAIN IN CONTROL OF THE 
E ATLC ANCHORED BY A 1024 MB HIGH NEAR 31N23W. 

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

$$
PAW