000
AXNT20 KNHC 201158
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

THE ITCZ IS ANALYZED FROM SW AFRICA NEAR 6N9W 3N15W 2N26W 
CROSSING THE EQUATOR NEAR 35W TO INLAND OVER SOUTH AMERICA. NO 
SIGNIFICANT CONVECTION IS NOTED. 

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE REMAINS OVER THE GULF INTO THE ATLC ANCHORED 
BY A 1022 MB HIGH S OF PENSACOLA FLORIDA NEAR 28N87W. BROAD 
UPPER RIDGE COVERS THE GULF WITH THE MEAN AXIS ALONG 88W WITH 
WATER VAPOR IMAGERY INDICATING MODERATE TO STRONG SUBSIDENCE 
ACROSS THE ENTIRE GULF BASIN. THIS IS PROVIDING CLEAR SKIES OVER 
MOST OF THE GULF AGAIN THIS MORNING. THE EXCEPTION IS OVER OF 
THE NW GULF WHERE PATCHES OF SCATTERED LOW CLOUDS AND FOG ARE N 
OF 27N W OF 91W TO INLAND OVER LOUISIANA AND TEXAS AND OVER THE 
FAR W GULF W OF 96W TO INLAND OVER MEXICO N OF VERACRUZ AND THE 
REMAINDER OF THE TEXAS. HIGH PRESSURE WILL DISSIPATE LATER 
TODAY. A WEAK COLD FRONT WILL MOVE INTO THE GULF EARLY TUE 
MOVING ACROSS THE GULF BEFORE BECOMING STATIONARY LATE TUE AND 
DISSIPATE ON WED. 

CARIBBEAN SEA...
AN UPPER TROUGH EXTENDING FROM THE W/CENTRAL ATLC COVERS THE N 
CARIBBEAN FROM THE YUCATAN PENINSULA TO THE LEEWARD ISLANDS. 
WATER VAPOR IMAGERY INDICATES VERY STRONG SUBSIDENCE ALOFT 
COVERING THE CARIBBEAN. HOWEVER...LOW LEVEL MOISTURE COUPLED 
WITH THE FRESH EASTERLY TRADE WINDS CONTINUE TO USHER IN PATCHES 
OF ISOLATED SHOWERS ACROSS MOST OF THE ENTIRE BASIN WITH THE 
EXCEPTION WITHIN 120 NM OF THE SOUTH AMERICAN COAST WHERE CLEAR 
SKIES PREVAIL. HIGH PRESSURE N OF THE CARIBBEAN WILL MOVE SE 
AND WEAKEN THROUGH TONIGHT. NEW HIGH BUILDS N OF THE AREA MON 
THROUGH WED ALLOWING FOR TRADE WINDS TO INCREASE...THEN DIMINISH 
OVER MUCH OF THE AREA WED. 

ATLANTIC OCEAN...
A SURFACE RIDGE THAT COVERS THE GULF OF MEXICO EXTENDS OVER THE 
FAR W ATLC W OF 70W. AN UPPER TROUGH COVERS THE W ATLC 
SUPPORTING A COLD FRONT THAT ENTERS THE REGION THROUGH 32N59W 
ALONG 28N66W TO 27N75W WITH SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS WITHIN 30 NM OF THE FRONT N OF 29N. HOWEVER... 
WATER VAPOR IMAGERY INDICATES MODERATE TO STRONG SUBSIDENCE 
ACROSS MOST OF THE W ATLC IS LIMITING ANY OTHER SHOWER ACTIVITY. 
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 100 KT IS RIDING N ALONG THE W PORTION OF THE UPPER RIDGE 
WITHIN 150/175 NM OF LINE FROM 19N52W 28N27W TO 30N11W. 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-25N E OF 35W 
LIMITING ANY SHOWER ACTIVITY IN THE AREA. A WEAK SURFACE TROUGH 
IS BENEATH THIS UPPER JETSTREAM EXTENDING FROM NEAR 31N35W TO 
25N43W. A SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A 1024 
MB HIGH NEAR 32N21W AND A WEAKNESS IN THE IMMEDIATE VICINITY OF 
THE SURFACE TROUGH.  

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

$$
PAW