[Tropical] Tropical Weather Discussion

[EMWIN Server]

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





This weather bulletin was brought to you by:
www.nashvilleweather.net