[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST MON DEC 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC

...THE ITCZ...

FROM THE SIERRA LEONE/LIBERIA BORDER TO 6N20W 6N30W 5N40W INTO
EXTREME NORTHEASTERN BRAZIL NEAR 3N52W. ISOLATED MODERATE SHOWERS
ARE SOUTH OF 8N IN THE ATLANTIC OCEAN.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA
THANKS TO THE RIDGE THAT EXTENDS FROM THE WEST CENTRAL CARIBBEAN
SEA NORTHEASTWARD ACROSS CUBA AND THE BAHAMAS INTO THE ATLANTIC
OCEAN ALONG THE U.S.A. EAST COAST. MIDDLE TO UPPER LEVEL DRY AIR/
SUBSIDENCE COVER THE SOUTHEASTERN HALF OF THE AREA. MIDDLE TO
UPPER LEVEL MOISTURE ON THE WESTERN SIDE OF THE RIDGE COVERS THE
NORTHWESTERN HALF OF THE AREA. UPPER LEVEL ANTICYCLONIC WIND FLOW
COVERS NORTH OF 28N WEST OF 110W. A MIDDLE TO UPPER LEVEL TROUGH
IS DEVELOPING FROM SOUTHEASTERN NEW MEXICO INTO WEST TEXAS. THE
REST OF TEXAS TO THE EAST OF THE DEVELOPING TROUGH FINDS ITSELF
ON THE WESTERN SIDE OF THE MIDDLE TO UPPER LEVEL CARIBBEAN SEA-
TO-WESTERN ATLANTIC OCEAN RIDGE. A COLD FRONT CONTINUES THROUGH
SOUTHEASTERN GEORGIA INTO NORTHERN FLORIDA EAST OF THE FLORIDA
PANHANDLE TO THE SOUTH CENTRAL GULF OF MEXICO INTO THE
SOUTHWESTERN CORNER OF THE AREA. THE FRONT BECOMES STATIONARY
IN THE SOUTHWESTERN CORNER OF THE AREA...INTO THE ISTHMUS OF
TEHUANTEPEC...AND THEN CURVING NORTHWESTWARD IN MEXICO TO 22N99W.
MODEL GUIDANCE SUGGESTS WILL WEAKEN AND SLOW DOWN IN ITS
EASTWARD MOVEMENT. IT MAY STALL OVER SOUTH FLORIDA AND THE
SOUTHEASTERN GULF OF MEXICO 18 TO 24 HOURS FROM NOW AS THE
FRONT LOSES ITS MIDDLE TO UPPER LEVEL SUPPORT.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE AREA OF EASTERN
HONDURAS/NORTHEASTERN NICARAGUA NORTHEASTWARD ACROSS CUBA AND
THE BAHAMAS INTO THE ATLANTIC OCEAN ALONG THE U.S.A. EAST COAST.
THIS RIDGE ENHANCES DRY AIR/SUBSIDENCE. A SEPARATE AREA OF
UPPER LEVEL ANTICYCLONIC FLOW ORIGINATES OVER NORTHERN SOUTH
AMERICA AND COVERS THE AREA EAST OF A SOUTHEASTERN CUBA-TO-
NORTHEASTERN NICARAGUA LINE. A DEEP LAYER TROUGH SUPERIMPOSES
ITSELF ON TOP OF THE NORTHEASTERN CORNER OF THE AREA PASSING
THROUGH 21N59W IN THE ATLANTIC OCEAN TO PUERTO RICO. ALL THE
PRECIPITATION WITH THIS TROUGH IS NORTH OF 20N AND EAST OF 60W.
BROAD SURFACE-TO-LOW LEVEL CYCLONIC FLOW AND UPPER LEVEL
ANTICYCLONIC OUTFLOW ARE ON TOP OF THE SOUTHWESTERN CORNER OF
THE AREA WHERE ISOLATED MODERATE SHOWERS ARE SOUTH OF 11N
BETWEEN 78W AND 82W.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE FROM THE WEST CENTRAL CARIBBEAN
SEA CROSSES CUBA AND THE BAHAMAS AND CONTINUES NORTHEASTWARD
BEYOND 33N70W. DEEP LAYER TROUGH PASSES THROUGH 35N44W TO
28N53W INTO THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA NEAR
19N63W. THIS TROUGH SUPPORTS THE COLD FRONT THAT PASSES THROUGH
32N35W TO A 1016 MB LOW PRESSURE CENTER NEAR 26N51W...TO ANOTHER
1016 MB LOW PRESSURE CENTER NEAR 24N58W TO 21N59W TO PUERTO RICO.
BROKEN TO OVERCAST MULTILAYERED CLOUDS AND ISOLATED MODERATE
SHOWERS ARE WITHIN 120 NM TO 180 NM ON EITHER SIDE OF THE LINE
THAT PASSES THROUGH 33N42W TO 27N49W TO 20N60W. A SEPARATE
SURFACE TROUGH STANDS ALONE ALONG 21N67W 24N73W 27N74W. POSSIBLE
SHOWERS ARE WITH THIS TROUGH. MOSTLY LOW CLOUDS ARE ROTATING
CYCLONICALLY AROUND THIS FEATURE. BROAD UPPER LEVEL WESTERLY-
TO-SOUTHWESTERLY WIND FLOW COVERS THE ATLANTIC WATERS SOUTH
OF 16N FROM THE EASTERN CARIBBEAN SEA TO AFRICA. BROAD EASTERLY
SURFACE WIND FLOW SOUTH OF 20N EAST OF 60W. SURFACE RIDGE
THROUGH 32N25W TO 27N37W 23N45W.

$$
MT



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