000
AXNT20 KNHC 200514
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0445 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N9W 3N15W CROSSING THE EQUATOR 
NEAR 19W THEN ALONG 2S BETWEEN 22W-36W AND INTO NE BRAZIL NEAR 
4S40W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 130 NM 
N OF THE AXIS BETWEEN 14W-20W. SCATTERED MODERATE CONVECTION IS 
S OF THE AXIS FROM THE EQUATOR TO 4N BETWEEN 8W-13W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP-LAYER TROUGH OVER THE EASTERN SEABOARD EXTENDS A COLD 
FRONT THROUGH THE W ATLANTIC ACROSS THE FLORIDA PENINSULA AND 
INTO THE GULF OF MEXICO. AS OF 0300 UTC...THE FRONT ENTERS THE 
GULF NEAR NAPLES AND CONTINUES ALONG 24N85W TO 23N94W WHERE IT 
DIPS SOUTH INTO THE WESTERN BAY OF CAMPECHE AS A STATIONARY 
FRONT AND CROSSES INLAND OVER MEXICO NEAR VERACRUZ. SCATTERED 
SHOWERS AND ISOLATED THUNDERSTORMS ARE OBSERVED ALONG THE 
BOUNDARY...PARTICULARLY W OF 86W. STRONG N TO NE WINDS OF 20-25 
KT CONTINUE TO ADVECT A COOLER AND DRIER AIRMASS ACROSS THE GULF 
IN THE WAKE OF THE FRONT. THE FRONT IS EXPECTED TO MOVE SE OF 
THE REGION FRI NIGHT WITH SFC HIGH PRESSURE SHIFTING EAST ACROSS 
THE GULF THROUGH SAT. AHEAD OF THE FRONT...FAIR WEATHER 
CONDITIONS ARE OBSERVED ACROSS THE SE GULF AND THE YUCATAN 
PENINSULA UNDER NEAR ZONAL FLOW AND MODERATE SUBSIDENCE ALOFT.

CARIBBEAN SEA...
HIGH PRESSURE OVER THE CENTRAL ATLANTIC IS MAINTAINING FRESH TO 
STRONG TRADE WIND FLOW ACROSS THE CARIBBEAN. THE STRONGEST 
WINDS...UP TO 30 KT...ARE OBSERVED ALONG THE COAST OF COLOMBIA. 
ISOLATED SHOWERS...REMNANTS OF A FRONTAL BOUNDARY...ARE MOVING 
ACROSS PUERTO RICO AND THE MONA PASSAGE. ADDITIONAL ISOLATED 
TRADE WIND SHOWERS ARE TRAVERSING THE CARIBBEAN MAINLY E OF 67W. 
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 0300 
UTC...THE FRONT ENTERS THE DISCUSSION AREA NEAR 31N73W... 
STRETCHES SOUTHWESTWARD ACROSS FLORIDA NEAR WEST PALM BEACH AND 
CONTINUES INTO THE GULF OF MEXICO. SCATTERED SHOWERS AND 
ISOLATED THUNDERSTORMS ARE OBSERVED WITHIN 50 NM OF THE FRONT. 
THE STRONG PRESSURE GRADIENT ACROSS THE FRONT IS GENERATING 
SOUTHWESTERLY GALE FORCE WINDS AHEAD OF THE FRONT TO 66W. EAST 
OF THE FRONT...FAIR WEATHER AND STRATOCUMULUS CLOUDS SURROUND A 
1027 MB SFC HIGH CENTERED NEAR 32N50W. A STRONG LOW-PRESSURE 
SYSTEM WELL NORTH OF THE DISCUSSION AREA EXTENDS A FRONTAL 
BOUNDARY INTO THE CENTRAL ATLC. THE STATIONARY FRONT ENTERS THE 
REGION NEAR 31N37W AND CONTINUES TO NEAR 25N44W WHERE IT BECOMES 
DIFFUSE TO NEAR 19N59W. SURFACE CONFLUENCE NEAR THIS BOUNDARY 
IS SUPPORTING INCREASED CLOUDINESS AND ISOLATED SHOWERS WITHIN 
60 NM EITHER SIDE OF THE FRONT. FAIR WEATHER ASSOCIATED WITH A 
SFC RIDGE COVERS THE E ATLC E OF 35W. IN THE TROPICS... 
DEEP-LAYER DRY AIR EMBEDDED WITHIN AN UPPER TROUGH IS 
SUPPRESSING CONVECTION OVER THE WRN HALF OF THE ITCZ. UPPER 
LEVEL DIVERGENCE E OF THIS TROUGH IS ENHANCING THE CONVECTION 
OVER THE ERN HALF OF THE ITCZ.

$$
WADDINGTON