[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250550
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI DEC 25 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 2N30W 1N40W EQ50W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 1N-4N
BETWEEN 26W-30W. ISOLATED MODERATE CONVECTION IS FROM 2N-4N
BETWEEN 11W-20W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 0300 UTC...A COLD FRONT EXTENDS FROM THE FLORIDA PANHANDLE
TO THE BAY OF CAMPECHE ALONG 31N86W 24N90W 19N96W. SCATTERED
SHOWERS ARE WITHIN 30 NM OF THE FRONT. WIDELY SCATTERED MODERATE
CONVECTION IS E OF THE FRONT OVER THE NE GULF OF MEXICO FROM
27N-30N BETWEEN 84W-86W. 20-30 KT NW WINDS ARE OVER THE W GULF
BEHIND THE FRONT. A SECONDARY COLD FRONT EXTENDS FROM LOUISIANA
TO THE NW GULF OF MEXICO ALONG 31N91W 26N93W BRINGING IN COLDER
TEMPERATURES...MORE LOW CLOUDS...AND HIGHER WINDS OVER THE NW
GULF. ELSEWHERE E OF THE FRONTS...RETURN FLOW WITH A TIGHT
SURFACE GRADIENT IS PRODUCING 20-25 KT SE SURFACE WINDS AND
BROKEN TO OVERCAST MULTILAYERED CLOUDS OVER THE E GULF OF MEXICO
AND FLORIDA. IN THE UPPER LEVELS...90-110 KT ZONAL FLOW WITH
STRONG SUBSIDENCE IS OVER THE W GULF W OF 90W. 50-70 KT ZONAL
FLOW WITH CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE E GULF E
OF 90W. EXPECT IN 24 HOURS...FOR THE TAIL END OF A COLD FRONT TO
EXTEND FROM S FLORIDA TO W CUBA WITH 10-15 KT NW WINDS OVER MOST
OF GULF W OF THE FRONT. CONVECTION WILL PERSIST OVER S FLORIDA
AND THE STRAITS OF FLORIDA.

THE CARIBBEAN SEA...
THE SURFACE PRESSURE GRADIENT HAS SLACKENED OVER THE CARIBBEAN
SEA AND CENTRAL AMERICA THUS MODERATE TRADEWINDS ARE NOTED OVER
THE AREA. SCATTERED MODERATE CONVECTION IS OVER PUERTO RICO AND
THE LEEWARD ISLANDS FROM 18N-20N BETWEEN 63W-67W. THE REMAINDER
OF THE SEA AND CENTRAL AMERICA HAS MOSTLY FAIR SKIES. IN THE
UPPER LEVELS...A TROUGH IS OVER THE WESTERN CARIBBEAN W OF 70W
WITH AXIS ALONG 80W. AN UPPER LEVEL RIDGE IS OVER THE REMAINDER
OF THE CARIBBEAN PRODUCING SW UPPER LEVEL WINDS. UPPER LEVEL
MOISTURE IS OVER THE EASTERN CARIBBEAN E OF 68W WHILE STRONG
SUBSIDENCE IS OVER THE REMAINDER OF THE CARIBBEAN. EXPECT OVER
THE NEXT 24 HOURS FOR CONTINUED SHOWERS AND CONVECTION OVER THE
LEEWARD ISLANDS.

THE ATLANTIC OCEAN...
THE TAIL END OF A COLD FRONT IS OVER THE W ATLANTIC ALONG 32N58W
29N66W. A 1011 MB LOW IS CENTERED OVER THE S BAHAMAS NEAR
22N70W. A STATIONARY FRONT EXTENDS E FROM THE LOW TO 22N64W.
SCATTERED MODERATE CONVECTION IS N OF THE LEEWARD ISLANDS FROM
20N-22N BETWEEN 60W-65W. A 1018 MB HIGH IS OVER THE CENTRAL
ATLANTIC NEAR 25N51W. IN THE UPPER LEVELS...A RIDGE IS OVER THE
W ATLANTIC W OF 70W. AN UPPER LEVEL TROUGH IS FURTHER E OVER THE
W ATLANTIC N OF 20N BETWEEN 50W-70W. ANOTHER UPPER LEVEL RIDGE
IS OVER THE CENTRAL ATLANTIC N OF 20N BETWEEN 30W-50W. ZONAL
FLOW IS OVER THE E ATLANTIC N OF 20N E OF 30W TO THE AFRICAN
COAST. IN THE TROPICS AN UPPER LEVEL HIGH IS CENTERED E OF THE
LESSER ANTILLES NEAR 12N55W. A RIDGE AXIS EXTENDS E TO THE CAPE
VERDE ISLANDS NEAR 16N25W. AN UPPER LEVEL LOW IS CENTERED
FURTHER S NEAR 4N40W. EXPECT IN 24 HOURS FOR A COLD FRONT TO BE
OVER THE W ATLANTIC E OF FLORIDA WITH CONVECTION...AND ANOTHER
COLD FRONT TO BE OVER THE CENTRAL ATLANTIC FROM 32N40W TO N OF
THE LEEWARD ISLANDS NEAR 20N60W WITH CONVECTION. ALSO EXPECT
GALE FORCE WINDS BEHIND THIS FRONT OVER THE CENTRAL ATLANTIC
NEAR 30N50W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE.

$$
FORMOSA





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