000
AXNT20 KNHC 210543
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT FEB 21 2009

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 
0615 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N12W CROSSING THE EQUATOR NEAR 
18W EXTENDING TO 4S30W AND INTO NE BRAZIL NEAR 5S36W. MUCH OF 
THE CONVECTIVE ACTIVITY IS CONCENTRATED SOUTH OF THE EQUATOR TO 
5S AND BETWEEN 15W-21W.

...DISCUSSION...

GULF OF MEXICO...
STRONG WESTERLY FLOW ALOFT COVERS THE GULF IN THE BASE OF A DEEP 
TROUGH OVER THE ERN CONUS AND W ATLC. THIS TROUGH SUPPORTS A 
COLD FRONT OVER THE W ATLC AND THE CENTRAL BAHAMAS WHICH IS 
DISSIPATING OVER CENTRAL CUBA AND THE NW CARIBBEAN. AT THE 
SURFACE...A HIGH PRES CENTERED OVER THE SE CONUS DOMINATES THE 
ENTIRE GULF. NE WINDS OF 20 TO 25 KT ARE NOTED AROUND THE 
PERIPHERY OF THIS HIGH AFFECTING THE SOUTHERN GULF WATERS S OF 
25N AND THE YUCATAN CHANNEL. ABUNDANT LOW/MID LEVEL CLOUDS WITH 
EMBEDDED LIGHT RAIN ARE BANKING UP AGAINST THE SIERRA MADRE 
MOUNTAINS IN MEXICO. ACROSS THE N GULF...MOSTLY CLEAR SKIES ARE 
NOTED DUE TO THE PRESENCE OF THE ABOVE MENTIONED SFC HIGH 
ANALYZED 1025 MB OVER SRN ALABAMA/WESTERN FLORIDA PANHANDLE. 
THIS HIGH WILL SLIDE NE OF THE AREA THROUGH SAT NIGHT AS A NEW 
COLD FRONT PUSHES INTO THE NW WATERS SAT EVENING FOLLOWED BY 
FRESH TO STRONG NLY WINDS. 

CARIBBEAN SEA...
A DYING COLD FRONT IS OVER THE NW CARIBBEAN AND CENTRAL CUBA 
EXTENDING FROM 20N87W TO 22N78W. SATELLITE IMAGERY SHOWS A 
NARROW BAND OF CLOUDS WITH ISOLATED SHOWERS ASSOCIATED WITH THE 
FRONTAL BOUNDARY. NE WINDS OF 20 TO 25 KT ARE BEHIND THE FRONT. 
FRESH TO STRONG TRADE WINDS ARE BLOWING ACROSS THE BASIN. THESE 
WINDS ARE FORECAST TO CONTINUE INTO TUESDAY WITH AN INCREASED 
PRESSURE GRADIENT ACROSS THE CARIBBEAN AS HIGH PRESSURE SETTLES 
IN BEHIND THE WEAKENING COLD FRONT. THE STRONGEST WINDS ARE 
FOUND ALONG THE COAST OF COLOMBIA...WHERE A GALE WARNING IS 
ALREADY IN EFFECT. PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED 
SHOWERS CONTINUE TO BE ADVECTED WWD ACROSS THE BASIN ON EASTERLY 
TRADE WINDS. ALOFT...A RIDGE EXTENDING FROM NRN SOUTH AMERICA 
DOMINATES MUCH OF THE REGION. SWLY FLOW ON THE WESTERN SIDE OF 
THE RIDGE ARE TRANSPORTING SOME MID/UPPER LEVEL MOISTURE ACROSS 
THE CENTRAL AND EASTERN CARIBBEAN. MODERATE TO STRONG SUBSIDENCE 
IS NOTED OVER CUBA AND THE NW CARIBBEAN. 

ATLANTIC OCEAN...
THE DEEP TROUGH OVER THE ERN CONUS AND W ATLC CONTINUES TO 
SLOWLY PROGRESS EWD. THE ATTENDANT COLD FRONT ENTERS THE 
FORECAST AREA NEAR 31N63W THEN CONTINUES SW ACROSS THE CENTRAL 
BAHAMAS INTO CENTRAL CUBA WHERE IT BEGINS TO DISSIPATE. LOW 
LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM 
EITHER SIDE OF THE FRONT. FARTHER TO THE E...A 1032 MB SURFACE 
HIGH CENTERED W OF THE AZORES NEAR 38N37W EXTENDS A RIDGE OVER 
THE REMAINDER OF THE CENTRAL AND E ATLC. AROUND THE SOUTHERN 
PERIPHERY OF THIS RIDGE...MODERATE TO FRESH TRADE WINDS ARE 
ADVECTING POCKETS OF LOW LEVEL MOISTURE ACROSS THE TROPICAL 
ATLANTIC INTO THE CARIBBEAN SEA. IN THE UPPER-LEVELS...A TROUGH/
RIDGE/TROUGH PATTERN DOMINATES THE ATLANTIC DISCUSSION AREA. THE 
RIDGE EXTENDS FROM THE CARIBBEAN INTO THE CENTRAL ATLC TO BEYOND 
31N52W. AN UPPER-LEVEL LOW IS NEAR 28N30W GENERATING SOME SHOWER 
ACTIVITY. A TROUGH STRETCHES FROM THE LOW TO NEAR 15N45W. STRONG 
SWLY FLOW IS SEEN AHEAD OF THIS TROUGH BETWEEN THE CANARY AND 
THE CAPE VERDE ISLANDS.   

$$
GR