[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE DEC 25 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 CENTRAL COASTAL WATERS OF SIERRA LEONE TO 8N14W 4N20W
4N40W...AND CURVING INTO NORTHEASTERN BRAZIL NEAR 2N51W.
WIDELY SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS FROM 3N TO 7N BETWEEN 34W AND 41W.
ISOLATED MODERATE SHOWERS EAST OF 18W.

...DISCUSSION...

THE GULF OF MEXICO...
A WELL-DEVELOPED TROUGH ON WATER VAPOR IMAGERY IS MOVING THROUGH
THE GULF OF MEXICO COAST OF TEXAS WITH NO SURFACE FRONTAL
BOUNDARY OR TROUGH. BROAD SURFACE HIGH PRESSURE COVERS TEXAS
INTO LOUISIANA. UPPER LEVEL MOISTURE FLOWS FROM THE EASTERN
PACIFIC OCEAN ACROSS MEXICO AND INTO THE GULF OF MEXICO WITHIN
250 NM TO THE EAST OF THE LEADING EDGE OF THE TEXAS TROUGH. THE
STATIONARY FRONT FROM THE WESTERN ATLANTIC OCEAN TO THE FLORIDA
EAST COAST EAST OF LAKE OKEECHOBEE AND TO WESTERN CUBA HAS
VIRTUALLY NO MIDDLE TO UPPER LEVEL SUPPORT. UPPER LEVEL
ANTICYCLONIC WIND FLOW FROM THE WEST CENTRAL CARIBBEAN SEA-TO-
CUBA/THE BAHAMAS/AND BEYOND 33N70W IN THE ATLANTIC OCEAN IS ON
TOP OF THE STATIONARY FRONT. A SURFACE TROUGH IS ALONG 79W/80W
FROM THE NORTHERN BAHAMAS TO 18N. THIS TROUGH HAS BEEN MOVING
WESTWARD IN THE ATLANTIC OCEAN DURING THE LAST TWO DAYS. THE
TROUGH AND FRONT COMBINATION MAY BRING RAIN TO PARTS OF FLORIDA
FOR THE NEXT DAY OR SO.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE WEST CENTRAL
CARIBBEAN SEA NORTHEASTWARD ACROSS CUBA AND THE BAHAMAS INTO THE
ATLANTIC OCEAN BEYOND 33N70W. ALONG THE U.S.A. EAST COAST. THIS
RIDGE ENHANCES DRY AIR/SUBSIDENCE. A SEPARATE AREA OF UPPER
LEVEL ANTICYCLONIC FLOW ORIGINATES IN COSTA RICA/NICARAGUA AND
SPREADS AS FAR TO THE NORTH AS HISPANIOLA AND PUERTO RICO. THIS
ANTICYCLONIC WIND FLOW EVENTUALLY CURVES TO THE EASTERN CARIBBEAN
SEA ISLANDS...AND INTO THE ATLANTIC OCEAN. A DEEP LAYER TROUGH
SUPERIMPOSES ITSELF ON TOP OF THE EASTERN SECTIONS OF THE AREA
WITH CYCLONIC WIND FLOW EAST OF 64W. A TROUGH ON WATER VAPOR
IMAGERY PASSES THROUGH 18N52W IN THE ATLANTIC OCEAN TO 16N64W
IN THE EASTERN CARIBBEAN SEA. BROAD SURFACE-TO-LOW LEVEL
CYCLONIC FLOW AND UPPER LEVEL ANTICYCLONIC OUTFLOW ARE ON TOP OF
THE SOUTHWESTERN CORNER OF THE AREA. SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS ARE FROM 9N TO 12N BETWEEN 81W
AND 83W IN THE COASTAL WATERS OF PANAMA AND COSTA RICA.

THE ATLANTIC OCEAN...
ANTICYCLONIC WIND FLOW ON WATER VAPOR IMAGERY FROM A MIDDLE TO
UPPER LEVEL RIDGE COVERS THE AREA WEST OF 60W. THE SAME DEEP
LAYER TROUGH IN THE CENTRAL ATLANTIC OCEAN FROM 24 HOURS AGO
REMAINS AT THIS TIME. THIS TROUGH SUPPORTS A STATIONARY FRONT
THAT PASSES THROUGH 32N35W TO 28N40W TO ONE 1016 MB LOW PRESSURE
CENTER NEAR 24N50W. A TROUGH CONNECTS THE 24N50W LOW PRESSURE
CENTER TO A SECOND 1016 MB LOW PRESSURE CENTER NEAR 20N52W...
AND THE TROUGH ENDS NEAR 14N53W. WIDELY SCATTERED TO SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 20N TO
24N BETWEEN 41W AND 54W. ISOLATED MODERATE SHOWERS...SOME ARE
DISSIPATING WITH TIME...FROM 15N TO 20N BETWEEN 43W AND 52W.
BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW IS SUPERIMPOSED ON TOP
OF A WEAK MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT
IS ABOUT 180 NM SOUTH OF THE CANARY ISLANDS. BROAD UPPER LEVEL
WESTERLY-TO-SOUTHWESTERLY WIND FLOW COVERS THE ATLANTIC WATERS
SOUTH OF 19N FROM THE EASTERN CARIBBEAN SEA TO AFRICA.

$$
MT




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