[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231126
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 23 2008

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
1045 UTC.

...THE ITCZ...
ITCZ IS CENTERED ALONG 9N10W 4N21W 4N46W 3N52W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-6N E
OF 29W ACROSS THE PRIME MERIDIAN. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE FROM 3N-10N BETWEEN 42W-57W INCLUDING
THE SOUTH AMERICAN COAST.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS FROM THE W ATLC INTO THE FLORIDA STRAITS
NEAR 23N80W CONTINUING AS A STATIONARY FRONT ALONG 23N91W TO A
1016 MB SURFACE LOW LOCATED OFF THE TEXAS COAST NEAR 26N96W WITH
A SECOND STATIONARY FRONT S FROM THE LOW TO 32N97W. A SURFACE
TROUGH EXTENDS N FROM THE SURFACE LOW TO OVER E TEXAS NEAR
CORPUS CHRISTI. A SURFACE RIDGE EXTENDS FROM OVER THE E US AND
THE N GULF BRIDGING THE FRONT DRAPED ACROSS THE GULF. BROKEN/
OVERCAST STRATOCUMULUS LOW CLOUDS WITH ISOLATED SHOWERS COVERING
MUCH OF THE GULF BUT IS BEGINNING TO PUSH N AS RETURN FLOW
AROUND THE SURFACE RIDGE. MODERATE/STRONG SUBSIDENCE AND DRY
STABLE AIR ARE NOTED ACROSS S FLORIDA AND THE S GULF WATERS
MAINLY S OF 25N.

CARIBBEAN SEA...
THE CARIBBEAN REMAINS UNDER THE INFLUENCE OF A BROAD UPPER HIGH
CENTERED NEAR 14N69W AND ENCOMPASSES THE ENTIRE CARIBBEAN BASIN
WITH STRONG SUBSIDENCE IN DRY AIR. THIS UPPER LEVEL FEATURE ALSO
ENVELOPS CENTRAL AMERICA AND THE N PORTION OF SOUTH AMERICA.
HOWEVER...AREAS OF SHALLOW LOW LEVEL MOISTURE CONTINUES TO
STREAM ACROSS THE BASIN USHERED IN ON NE-E TRADE WINDS WITH
ISOLATED SHOWERS DOTTING MOST OF THE ENTIRE CARIBBEAN INCLUDING
THE LESSER ANTILLES. LOOKING AHEAD...STRONG HIGH PRESSURE IS
FORECAST TO BUILD N OF AREA WITH INCREASING TRADE WINDS EXPECTED
OVER THE TROPICAL ATLC AND MUCH OF THE CARIBBEAN TODAY THROUGH
FRI.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE W ATLC NEAR 32N60W AND EXTENDS ACROSS
THE BAHAMAS NEAR 24N76W INTO THE FLORIDA STRAITS NEAR 23N80W AS
A STATIONARY BOUNDARY INTO THE GULF OF MEXICO. BROKEN/OVERCAST
STRATOCUMULUS LOW CLOUDS WITH ISOLATED SHOWERS ARE WITHIN 150 NM
NW OF THE FRONT WITH COLD AIR STRATOCUMULUS CLOUDS COVERING THE
REMAINDER OF THE AREA N OF THE FRONT. A BROAD UPPER LEVEL RIDGE
EXTENDS FROM THE CARIBBEAN WITH AXIS ACROSS THE VIRGIN/LEEWARD
ISLANDS NE TO BEYOND 32N47W. MOSTLY FAIR WEATHER CONDITIONS ARE
OBSERVED E OF THE COLD FRONT TO 30W WITH A WEAK 1026 MB HIGH
NEAR 27N56W. A SURFACE TROUGH IS IN THE CENTRAL ATLC EXTENDING
ALONG 48W FROM 16N-25N SUPPORTED BY UPPER LEVEL TROUGHING
EXTENDING FROM THE E/CENTRAL ATLC NEAR 32N23W SW ALONG 21N34W
INTO THE TROPICS ALONG 15N44W AND THEN W TO NEAR 13N55W. UPPER
DIFFLUENCE E OF THIS UPPER TROUGH ALONG WITH AN UPPER RIDGE
AMPLIFIED ALONG THE W AFRICAN COAST IS ENHANCING SCATTERED
SHOWERS WITHIN 175 NM EITHER SIDE OF A LINE FROM 12N33W TO OVER
W AFRICA NEAR MAURITANIA AND WESTERN SAHARA. NE TO E WINDS HAVE
INCREASED ACROSS THE TROPICS AND WILL CONTINUE THROUGH FRI.

$$
WALLACE







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