[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120008
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT 11 DEC 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN
COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 2345 UTC.

...ITCZ...

ITCZ 9N13W 5N25W 10N40W 11N50W 10N62W...AND FROM 6N77W AT
COLOMBIA COAST TO 6N83W. SCATTERED MODERATE TO ISOLATED STRONG
SHOWERS AND THUNDERSTORMS WITHIN 30 NM ON EITHER SIDE OF 3N23W
7N30W...FROM 10N TO 13N BETWEEN 38W AND 42W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE LINGERING SHOWERS/THUNDERSTORMS
FROM 9N TO 13N BETWEEN 50W AND 57W...AND FROM 6N TO 12N BETWEEN
57W AND 62W.

...DISCUSSION...

THE GULF OF MEXICO...
DEEP LAYER TROUGH MOVING THROUGH THE EASTERN UNITED STATES FROM
NEW ENGLAND TO FLORIDA...INCLUDING THROUGH THE EASTERN GULF OF
MEXICO. MIDDLE TO UPPER LEVEL NORTHWESTERLY TO WESTERLY FLOW
WEST OF THE TROUGH...IN THE MIDDLE OF MIDDLE TO UPPER LEVEL DRY
AIR EVERYWHERE. SURFACE HIGH PRESSURE HAS BEEN BUILDING ACROSS
THE GULF WATERS FROM WEST TO EAST. SURFACE COLD FRONT...SUPPORTED
BY THIS DEEP LAYER TROUGH...THROUGH THE WESTERN ATLANTIC OCEAN
NEAR 31N74W...OVER THE NORTHERN BAHAMAS NEAR 26N77W...TO WESTERN
CUBA NEAR 23N81W...INTO THE NORTHWESTERN CARIBBEAN SEA NEAR
20N85W...TO THE GULF OF HONDURAS AND GUATEMALA NEAR 15N90W.
STATIONARY FRONT 15N90W TO THE EASTERN EDGE OF THE ISTHMUS
OF TEHUANTEPEC...AND STARTING UP AGAIN FROM THE WESTERN EDGE OF
THE ISTHMUS TO 20N101W AND 24N104W. WIDELY SCATTERED MODERATE
SHOWERS AND POSSIBLE THUNDERSTORMS IN THE WESTERN ATLANTIC OCEAN
WITHIN 60 NM ON EITHER SIDE OF LINE THROUGH 31N72W 28N75W TO THE
COAST OF CUBA NEAR 22.5N79W. ISOLATED MODERATE TO LOCALLY STRONG
SHOWERS AND THUNDERSTORMS FROM 26N TO 30N BETWEEN 66W AND 70W.
RETURN FLOW WILL DEVELOP IN THE WESTERN GULF OF MEXICO BY SUNDAY
IN ADVANCE OF THE NEXT COLD FRONT...FORECAST TO MOVE INTO THE
NORTHWESTERN GULF EARLY MONDAY. THIS NEXT FRONT WILL LACK
MOISTURE AND PRODUCE ONLY WIDELY SCATTERED LIGHT SHOWERS.
MIDDLE TO UPPER LEVEL DYNAMICS WILL BE ABSENT AS A MORE
ZONAL PATTERN EVOLVES MONDAY AND TUESDAY.

THE CARIBBEAN SEA...
A SURFACE COLD GOES FROM WESTERN CUBA NEAR 23N81W...INTO THE
NORTHWESTERN CARIBBEAN SEA NEAR 20N85W...TO THE GULF OF HONDURAS
AND GUATEMALA NEAR 15N90W. THIS FRONT IS ASSOCIATED WITH THE DEEP
LAYER TROUGH FROM THE NORTHEASTERN UNITED STATES TO FLORIDA AND
THE EASTERN GULF OF MEXICO. CIMSS SATELLITE DERIVED WIND DATA AT
11/2100 UTC AND CURRENT WATER VAPOR IMAGERY SHOW MIDDLE TO UPPER
LEVEL WESTERLY WINDS IN THE NORTHWESTERN CORNER OF THE AREA...
AND SLIGHT MIDDLE TO UPPER LEVEL ANTICYCLONIC FLOW BETWEEN 60W
AND 77W. UPPER LEVEL SOUTHWEST-TO-WEST WINDS ARE SOUTH OF 10N
IN THE SOUTHWESTERN CORNER OF THE AREA. MIDDLE TO UPPER LEVEL
DRY AIR EVERYWHERE...EXCEPT FOR SOME MULTILAYERED MOISTURE AND
POSSIBLE SHOWERS/THUNDERSTORMS FROM THE ITCZ AREA OF THE
SOUTHEASTERN CORNER TO HISPANIOLA.

THE ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 19N52W...
UNDER A MIDDLE TO MOSTLY UPPER LEVEL RIDGE THROUGH 32N57W 26N61W.
CYCLONIC FLOW FROM THE CENTER GOES FROM 13N TO 22N BETWEEN 48W
AND 61W...SURROUNDED BY MIDDLE TO UPPER LEVEL DRY AIR IN THE
WESTERN SEMICIRCLE...AND ISOLATED MODERATE TO LOCALLY STRONG
SHOWERS AND THUNDERSTORMS FROM 15N TO 20N BETWEEN 45W AND 54W
TO THE EAST. THE BASE OF A NORTHWEST-TO-SOUTHEAST ORIENTED
MIDDLE TO UPPER LEVEL TROUGH REACHES 32N19W...OVER THE AZORES
TO THE MADEIRA ISLANDS. THIS TROUGH SUPPORTS A SURFACE COLD FRONT
THROUGH 32N23W 28N26W 28N30W 27N40W 30N47W. ISOLATED SHOWERS
POSSIBLE NORTH OF 26N40W 25N30W 28N20W. SURFACE TROUGH FROM THE
CANARY ISLANDS TO 25N19W 23N24W. SURFACE RIDGE FROM 1026 MB HIGH
PRESSURE CENTER NEAR 33N49W TO 28N59W TO 23N67W.

$$
MT


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