[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251158
TWDAT

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

...THE ITCZ...

FROM THE SOUTHERN LIBERIA COAST TO 3N20W 3N30W 4N43W CURVING
INTO NORTHEASTERN BRAZIL NEAR 1N51W. SCATTERED STRONG SHOWERS/
THUNDERSTORMS FROM 4N TO 6N BETWEEN 33W AND 37W. ISOLATED
MODERATE SHOWERS ARE ELSEWHERE SOUTH OF 6N BETWEEN 10W AND
20W...FROM 2N TO 6N BETWEEN 20W AND 30W...FROM 2N TO 7N
BETWEEN 30W AND 40W...AND FROM 3N TO 8N BETWEEN 40W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...
A WELL-DEVELOPED TROUGH ON WATER VAPOR IMAGERY IS MOVING THROUGH
LOUISIANA AND THE NORTHWESTERN CORNER OF 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 180 NM TO THE EAST OF THE LEADING
EDGE OF THE LOUISIANA 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 AND APPEARS TO BE IN A SITUATION OF BEING PUSHED
WESTWARD ON TOP OF FLORIDA AS A SURFACE TROUGH MOVES WESTWARD.
UPPER LEVEL ANTICYCLONIC WIND FLOW FROM THE WEST CENTRAL
CARIBBEAN SEA-TO-CUBA/THE BAHAMAS/AND BEYOND BERMUDA 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 BERMUDA. 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
18N51W 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 8N TO 9N BETWEEN 76W AND 78W FROM
COLOMBIA TO PANAMA INCLUDING IN THE GULF OF URABA.
NUMEROUS STRONG SHOWERS/THUNDERSTORMS ARE MOSTLY ALONG THE
PANAMA COAST...COVERING A SMALL PART OF EASTERN COSTA RICA
COASTAL WATERS SOUTH OF 10N BETWEEN 81W AND 83W.

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 25N48W TO A 1016 MB LOW
PRESSURE CENTER NEAR 23N50W. A TROUGH CONTINUES FROM THE 23N50W
LOW PRESSURE CENTER TO 16N52W. ISOLATED MODERATE SHOWERS WITHIN
180 NM ON EITHER SIDE OF 17N52W 25N40W...AND WITHIN 120 NM ON
EITHER SIDE OF 27N40W BEYOND 32N37W. BROAD UPPER LEVEL
ANTICYCLONIC WIND FLOW IS SUPERIMPOSED ON TOP OF A WEAK MIDDLE
TO UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT IS ABOUT 200 NM
SOUTH OF THE CANARY ISLANDS. BROAD UPPER LEVEL WESTERLY-TO-
SOUTHWESTERLY WIND FLOW COVERS THE ATLANTIC WATERS SOUTH OF
14N60W 14N50W 20N34W BEYOND 19N10W FROM THE EASTERN CARIBBEAN
SEA TO AFRICA. THE CENTRAL ATLANTIC OCEAN TROUGH HAS BEEN DIGGING
IN THE DIRECTION OF 14N60W-14N50W AND THAT IS WHY THE FLOW HAS
BEEN PUSHED COMPARATIVELY SO FAR TO THE SOUTH. THE WESTERLY-TO-
SOUTHWESTERLY FLOW WAS AS FAR TO THE NORTH AS 18N A FEW DAYS AGO
BEFORE THE TROUGH STARTED TO DIG IN THAT AREA.


$$
MT




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