[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251124
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 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 0900 UTC...A 1021 MB HIGH IS CENTERED OVER NORTH MEXICO
NEAR 27N99W. A COLD FRONT EXTENDS FROM THE FLORIDA PANHANDLE TO
THE YUCATAN PENINSULA TO SOUTH MEXICO ALONG 31N84W 23N87W
17N94W. WIDELY SCATTERED MODERATE CONVECTION IS OVER THE E GULF
OF MEXICO WITHIN 120 NM E OF THE FRONT N OF 22N. 20-30 KT NW
WINDS ARE OVER THE W GULF BEHIND THE FRONT. RETURN FLOW WITH A
TIGHT SURFACE GRADIENT REMAINS OVER FLORIDA PRODUCING 20-25 KT
SE SURFACE WINDS AND BROKEN TO OVERCAST MULTILAYERED CLOUDS. IN
THE UPPER LEVELS...90-110 KT ZONAL FLOW WITH STRONG SUBSIDENCE
IS OVER THE W GULF W OF 88W. 50-70 KT ZONAL FLOW WITH
CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE E GULF E OF 88W.
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 TO ISOLATED STRONG CONVECTION IS
OVER PUERTO RICO AND THE LEEWARD ISLANDS FROM 17N-19N 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...
AS OF 0900 UTC...A WEAK 1012 MB LOW IS CENTERED OVER THE S
BAHAMAS NEAR 21N70W. A COLD FRONT IS OVER THE W ATLANTIC FROM
32N49W TO HISPANIOLA ALONG 24N56W 19N68W. SCATTERED MODERATE TO
STRONG CONVECTION IS N OF THE LEEWARD ISLANDS FROM 20N-22N
BETWEEN 59W-64W. A 1016 MB HIGH IS OVER THE CENTRAL ATLANTIC
NEAR 20N46W. 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 FROM 32N75W WITH CONVECTION...AND ANOTHER
COLD FRONT TO BE OVER THE CENTRAL ATLANTIC FROM 32N35W TO E OF
THE LEEWARD ISLANDS NEAR 18N60W WITH CONVECTION. ALSO EXPECT
GALE FORCE WINDS BEHIND THIS FRONT OVER THE CENTRAL ATLANTIC
NEAR 30N40W.

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

$$
FORMOSA






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