[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041141
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 04 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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

...THE ITCZ...
ITCZ IS CENTERED ALONG 8N12W 5N25W 5N35W 4N45W AND INTO SOUTH
AMERICA NEAR 3N51W. A CLUSTER OF MODERATE CONVECTION IS FROM
8N-9N BETWEEN 16W-18W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION WITHIN 40 NM EITHER SIDE OF THE AXIS BETWEEN 20W-28W.
WIDELY SCATTERED MODERATE CONVECTION FROM 3N-8N BETWEEN 33W-39W.

DISCUSSION...

THE GULF OF MEXICO...
AS OF 0900 UTC...A COLD FRONT EXTENDS FROM SOUTH FLORIDA TO
VERACRUZ MEXICO ALONG 25N81W 24N87W 23N93W 19N96W. A THIN BAND
OF SCATTERED SHOWERS IS WITHIN 60 NM OF THE FRONT. THE FRONT IS
EXPECTED TO STALL OVER THE FLORIDA STRAIGHTS AND GRADUALLY
DISSIPATE THROUGH WED. WINDS AHEAD OF THE FRONT S OF 22N AND W
OF 93W REMAIN N 20-25 KT BUT ARE EXPECTED TO DECREASE FOLLOWING
THE FRONTAL PASSAGE. THE REMAINDER OF THE GULF IS EXPERIENCING
LIGHT WINDS AND FAIR WEATHER DUE TO BUILDING HIGH PRESSURE
BEHIND THE FRONT. ALOFT...AN UPPER TROUGH IS OVER THE GULF
SUPPORTING THE COLD FRONT. A THIN BAND OF UPPER LEVEL MOISTURE
EXTENDS ABOVE THE FRONT. STRONG SUBSIDENCE AND DRY AIR COVER THE
REMAINDER OF THE GULF.

THE CARIBBEAN SEA...
DRY AND STABLE AIR BETWEEN AN UPPER RIDGE OVER THE CARIBBEAN AND
THE UPPER TROUGH OVER THE GULF DOMINATE THE NW CARIBBEAN.
SCATTERED SHOWERS ARE NOTED FROM 11N-14N BETWEEN 79W-83W.
PATCHES OF SCATTERED SHOWERS TRAILING FROM A SURFACE TROUGH EAST
OF THE LEEWARD ISLANDS ARE SEEN S OF PUERTO RICO FROM 16N-18N
BETWEEN 65W-67W AND IN THE ANEGADA PASSAGE BETWEEN ANGUILLA AND
THE BRITISH VIRGIN ISLANDS. A WEAK SURFACE PRESSURE GRADIENT IS
PROVIDING LIGHT N TO NE WINDS ACROSS THE CARIBBEAN.

THE ATLANTIC OCEAN...
AS OF 0900 UTC...A COLD FRONT ENTERS THE REGION NEAR 31N69W AND
EXTENDS SW ACROSS THE W ATLC CROSSING SOUTH FLORIDA NEAR 26N80W.
A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS IS WITHIN 60 NM OF
THE FRONT. FARTHER EAST...A 1019 MB HIGH IS CENTERED NEAR 30N48N
PRODUCING FAIR WEATHER STRATOCUMULUS OVER THE CENTRAL ATLC. THE
SURFACE HIGH IS EXPECTED TO MOVE RAPIDLY TO THE NE OVER THE NEXT
24 HOURS. A 1012 MB SURFACE LOW IS CENTERED NEAR 22N50W WITH A
SURFACE TROUGH EXTENDING FROM THE LOW CENTER TO NEAR 19N60W. A
COLD FRONT SUPPORTED BY AN UPPER LEVEL TROUGH EXTENDS FROM A
STRONG SURFACE LOW WELL NORTH OF THE AREA THROUGH 30N35W 26N40W
AND 23N46W. A BROAD BAND OF MOISTURE EXTENDS UP TO 200 NM AHEAD
OF THE FRONT N OF 21N. IN THE TROPICAL ATLC...A WEAK SURFACE
TROUGH STRETCHES FROM 16N58W TO 10N58W. A SIMILAR TROUGH BREAKS
THE ITCZ AXIS ALONG 47/48W AND STRETCHES FROM 2N-8N.
ALOFT...MOISTURE/HIGH CLOUDS ARE BEING TRANSPORTED EASTWARD
AROUND A BROAD E-W UPPER RIDGE COVERING THE TROPICAL ATLC S OF
21N.

$$
WADDINGTON




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