[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 241154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 UTC

...THE ITCZ...

FROM THE SIERRA LEONE/LIBERIA BORDER TO 7N27W 5N40W INTO EXTREME
NORTHEASTERN BRAZIL NEAR 3N52W. ISOLATED MODERATE SHOWERS ARE
SOUTH OF 8N IN THE ATLANTIC OCEAN FROM THE PRIME MERIDIAN AND
SOUTH AMERICA.

...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 MEXICO NORTH OF 28N WEST OF 108W. A MIDDLE TO UPPER LEVEL
TROUGH HAS MOVED FROM SOUTHEASTERN NEW MEXICO INTO CENTRAL
TEXAS. THE REST OF TEXAS TO THE EAST OF THE 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 32N77W IN THE ATLANTIC OCEAN TO FLORIDA ABOUT 30 NM
NORTHWEST OF LAKE OKEECHOBEE TO THE SOUTHEASTERN GULF OF MEXICO.
THE FRONT BECOMES STATIONARY IN THE SOUTHEASTERN CORNER OF THE
AREA...CURVING TOWARD THE SOUTHWESTERN CORNER OF THE AREA AND
INTO THE ISTHMUS OF TEHUANTEPEC...AND THEN CURVING NORTHWESTWARD
FROM JUST WEST OF THE ISTHMUS OF TEHUANTEPEC TO 22N99W. MODEL
GUIDANCE SUGGESTS THAT THE FRONT WILL WEAKEN AND SLOW DOWN IN
ITS EASTWARD MOVEMENT. IT MAY STALL OVER SOUTH FLORIDA AND THE
SOUTHEASTERN GULF OF MEXICO DURING THE NEXT 24 HOURS AS THE
FRONT LOSES ITS MIDDLE TO UPPER LEVEL SUPPORT. BROKEN LOW CLOUDS
AND POSSIBLE SHOWERS ACCOMPANY THE FRONT.

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 27N52W IN THE ATLANTIC OCEAN TO PUERTO RICO. ALL THE
PRECIPITATION WITH THIS TROUGH IS NORTH OF 18N AND EAST OF 57W.
BROAD SURFACE-TO-LOW LEVEL CYCLONIC FLOW AND UPPER LEVEL
ANTICYCLONIC OUTFLOW ARE ON TOP OF THE SOUTHWESTERN CORNER OF
THE AREA.  NUMEROUS STRONG SHOWERS/THUNDERSTORMS ARE IN THE
GULF OF URABA OF NORTHWESTERN COLOMBIA. SCATTERED MODERATE TO
STRONG SHOWERS/THUNDERSTORMS ARE ALONG THE PANAMA COAST WITHIN
A 20 NM RADIUS OF 10N78.5W...AND FROM 9N TO 10N BETWEEN
80W AND 81W...ALSO NORTH OF PANAMA.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE FROM THE WEST CENTRAL CARIBBEAN
SEA CROSSES CUBA AND THE BAHAMAS AND CONTINUES NORTHEASTWARD
BEYOND 32N70W. ONE SURFACE TROUGH STANDS ALONE ALONG 73W/74W
FROM GREAT INAGUA TO 28N. POSSIBLE SHOWERS ARE WITH THIS TROUGH.
MOSTLY LOW CLOUDS ARE ROTATING CYCLONICALLY AROUND THIS FEATURE.
A DEEP LAYER TROUGH PASSES THROUGH 35N44W TO 27N52W INTO THE
NORTHEASTERN CORNER OF THE CARIBBEAN SEA NEAR PUERTO RICO. THIS
TROUGH SUPPORTS THE COLD FRONT THAT PASSES THROUGH 32N35W TO
28N47W. A TROUGH CONTINUES FROM 28N47W TO A 1015 MB LOW PRESSURE
CENTER NEAR 23N57W TO 20N63W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS AND ISOLATED MODERATE SHOWERS ARE FROM 18N TO 26N BETWEEN
45W AND 57W...AND WITHIN 120 NM TO 180 NM ON EITHER SIDE OF THE
LINE THAT PASSES THROUGH 26N50W 29N45W BEYOND 32N41W. BROAD
UPPER LEVEL WESTERLY-TO-SOUTHWESTERLY WIND FLOW COVERS THE
ATLANTIC WATERS SOUTH OF 17N/18N FROM THE EASTERN CARIBBEAN SEA
TO AFRICA. BROAD EASTERLY SURFACE WIND FLOW SOUTH OF 20N EAST OF
60W. A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH THE NORTHERN
HALF OF MOROCCO TO THE CANARY ISLANDS TO 24N31W. A SURFACE RIDGE
IS UNDER THIS TROUGH...FROM A 1028 MB HIGH PRESSURE CENTER NEAR
33N20W TO 30N29W 26N36W 23N41W TO 17N55W.

$$
MT


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