000
AXNT20 KNHC 201104
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI FEB 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N6W CROSSES THE EQUATOR NEAR 
14W THEN ALONG 2S20W 3S30W AND INTO NE BRAZIL NEAR 4S39W. 
SCATTERED MODERATE CONVECTION IS FROM 2S-5S BETWEEN2W-7W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM THE 
EQUATOR TO 5N BETWEEN 7W-19W. 

...DISCUSSION...

GULF OF MEXICO...
A DEEP-LAYER TROUGH OVER THE EASTERN SEABOARD SUPPORTS A COLD 
FRONT ACROSS THE W ATLANTIC...BAHAMAS...AND GULF OF MEXICO. AS 
OF 0900 UTC...THE FRONT ENTERS THE GULF THROUGH THE STRAIGHTS OF 
FLORIDA AND CONTINUES ALONG 23N85W TO 23N90W WHERE IT BECOMES 
STATIONARY THROUGH THE WESTERN BAY OF CAMPECHE AND CROSSES 
INLAND OVER MEXICO NEAR COATZACOALCOS. MOST OF THE CONVECTIVE 
ACTIVITY ASSOCIATED WITH THE FRONT HAS DIMINISHED..HOWEVER 
MULTI-LEVEL CLOUDS AND ISOLATED SHOWERS REMAIN ALONG THE 
BOUNDARY. STRONG N TO NE WINDS OF 20-25 KT CONTINUE TO USHER A 
COOLER AND DRIER AIRMASS ACROSS THE GULF IN THE WAKE OF THE 
FRONT. A 1027 MB HIGH OVER TEXAS IS PRODUCING FAIR WEATHER AND 
CLEAR SKIES ACROSS THE NW GULF N OF 27N. THIS HIGH IS EXPECTED 
TO SHIFT EAST AS THE FRONTAL BOUNDARY MOVES OUT OF THE REGION 
TONIGHT.

CARIBBEAN SEA...
HIGH PRESSURE OVER THE CENTRAL ATLANTIC IS MAINTAINING FRESH TO 
STRONG TRADE WIND FLOW ACROSS THE CARIBBEAN WITH THE STRONGEST 
WINDS...UP TO 30 KT...OBSERVED ALONG THE COAST OF COLOMBIA. 
ISOLATED SHOWERS ARE MOVING ACROSS PUERTO RICO...THE MONA 
PASSAGE...THE LESSER ANTILLES...AND THE CARIBBEAN WATERS E OF 
67W. LOW LEVEL WIND CONVERGENCE IS GENERATING SCATTERED SHOWERS 
ALONG THE COAST OF COSTA RICA. CONVECTION IN THE CARIBBEAN 
REMAINS SHALLOW DUE TO STRONG SUBSIDENCE AROUND AN UPPER-LEVEL 
RIDGE THAT EXTENDS FROM SOUTH AMERICA TO THE NW CARIBBEAN.

ATLANTIC OCEAN...
A COLD FRONT ASSOCIATED WITH A DEEP-LAYER TROUGH OVER THE 
EASTERN SEABOARD STRETCHES ACROSS THE W ATLC. AS OF 0900 
UTC...THE FRONT ENTERS THE W ATLC NEAR 31N69W AND CONTINUES 
ACROSS THE BAHAMAS AND THROUGH THE FLORIDA STRAIGHTS INTO THE 
GULF OF MEXICO. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE 
OBSERVED WITHIN 50 NM OF THE FRONT N OF 26N. THE STRONG PRESSURE 
GRADIENT ACROSS THE FRONT IS GENERATING SOUTHWESTERLY GALE FORCE 
WINDS N OF 29N BETWEEN THE BOUNDARY AND 66W. FAIR WEATHER AND 
STRATOCUMULUS CLOUDS SURROUND A 1028 MB SFC HIGH CENTERED NEAR 
32N45W. A DISSIPATING FRONTAL BOUNDARY ASSOCIATED WITH A LOW 
PRESSURE SYSTEM WELL NORTH OF THE AREA ENTERS THE CENTRAL ATLC 
NEAR 31N35W BECOMING DIFFUSE NEAR 27N40W TO 21N57W. SURFACE 
CONFLUENCE NEAR THIS BOUNDARY IS SUPPORTING INCREASED CLOUDINESS 
AND ISOLATED SHOWERS WITHIN 40 NM EITHER SIDE OF THE FRONT. FAIR 
WEATHER ASSOCIATED WITH A SFC RIDGE COVERS THE ATLC E OF 34W. IN 
THE TROPICS... DEEP-LAYER DRY AIR AT THE BASE OF AN UPPER TROUGH 
IS SUPPRESSING CONVECTION OVER THE WRN HALF OF THE ITCZ WHILE  
UPPER LEVEL DIVERGENCE E OF THIS TROUGH IS ENHANCING THE 
CONVECTION OVER THE ERN HALF OF THE ITCZ.

$$
WADDINGTON