[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI DEC 04 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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N9W 4N13W 6N32W 3N51W. SCATTERED
SHOWERS AND CLUSTERS OF ISOLATED MODERATE CONVECTION ARE FROM THE
EQUATOR TO 12N BETWEEN 25W-42W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A STATIONARY FRONT EXTENDS FROM MIAMI FLORIDA
ACROSS THE WESTERN FLORIDA STRAITS SW TO THE YUCATAN CHANNEL. MOSAIC
DOPPLER RADAR IMAGERY AND LIGHTNING DATA SHOW ISOLATED SHOWERS AND
TSTMS WITHIN 60 NM EITHER SIDE OF THE FRONTAL BOUNDARY. THIS FRONTAL
SYSTEM IS SUPPORTED ALOFT BY A LONGWAVE UPPER LEVEL TROUGH COVERING
THE CENTRAL CONUS WITH SWLY UPPER LEVEL FLOW COVERING THE ENTIRE
GULF. INCREASED MIDDLE TO UPPER LEVEL MOISTURE IS OBSERVED IN WATER
VAPOR IMAGERY WITH SWLY FLOW AHEAD OF THE NEXT MID-LEVEL SHORTWAVE
TROUGH CURRENTLY OVER THE SW CONUS AND NW MEXICO THAT IS EXPECTED TO
INDUCE CYCLOGENESIS OVER THE WESTERN GULF BY FRIDAY AFTERNOON. THE
ASSOCIATED COLD FRONT IS FORECAST TO PUSH EAST THROUGH THE GULF BY
LATE SATURDAY PRODUCING STRONG NORTHERLY WINDS BEHIND THE FRONT.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE COVERS THE WESTERN CARIBBEAN W OF 70W ANCHORED
IN THE E PACIFIC WITH AXIS EXTENDING ACROSS NICARAGUA/HONDURAS
THROUGH THE WINDWARD PASSAGE INTO THE W ATLC. STRONG SUBSIDENCE AND
THE LACK OF MOISTURE IS NOTED ON WATER VAPOR IMAGERY WHICH
ACCOMPANIES THE UPPER LEVEL ANTICYCLONIC CIRCULATION BRINGING
TRANQUIL WEATHER AND FAIR SKIES TO MUCH OF THE BASIN. HOWEVER...WITH
THE STATIONARY FRONT DRAPED ACROSS THE YUCATAN CHANNEL...ISOLATED
SHOWERS AND TSTMS ARE N OF 20N FROM 81W-88W. EAST OF 70W...AN UPPER
LEVEL TROUGH AXIS EMBEDDED WITHIN VERY STRONG SUBSIDENCE EXTENDS
FROM THE CENTRAL ATLC ALONG 17N60W 13N68W TO NORTHERN COLOMBIA.
ISOLATED LOW-LEVEL SHOWERS ARE BEING USHERED IN ON FRESH TO STRONG
TRADEWINDS ACROSS THE EASTERN CARIBBEAN AND LESSER ANTILLES MAINLY E
OF 70W. ALSO...LOW-LEVEL SPEED CONVERGENCE OF THE EASTERLY
TRADEWINDS ACROSS THE SW CARIBBEAN ARE GENERATING ISOLATED SHOWERS
WITHIN 60 NM ALONG THE COAST OF WESTERN PANAMA AND COSTA RICA.

ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE W ATLC AND ENTERS THE DISCUSSION
AREA NEAR 32N73W TO NEAR MIAMI FLORIDA. SATELLITE IMAGERY AND
LIGHTNING DATA INDICATE ISOLATED SHOWERS AND TSTMS ARE OCCURRING
WITHIN 90 NM EAST OF THE FRONT. ABUNDANT MOISTURE IS NOTED ALOFT AS
SWLY UPPER LEVEL FLOW DOMINATES ACROSS THE W ATLC W OF 66W. THE
REMAINDER OF THE W ATLC IS COVERED BY A SURFACE RIDGE ANCHORED ON A
1029 MB HIGH CENTERED NEAR 35N47W. THE RIDGE IS SUPPORTED ALOFT BY
AN AMPLIFIED UPPER LEVEL RIDGE AXIS EXTENDING FROM THE WESTERN
CARIBBEAN THROUGH THE WINDWARD PASSAGE TO BEYOND 32N62W. ACROSS THE
CENTRAL ATLC...AN UPPER LEVEL LOW IS CENTERED NEAR 24N42W. THIS
UPPER LEVEL FEATURE SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION
AREA NEAR 32N38W EXTENDING SW TO 30N40W WHERE IT CONTINUES AS A
SURFACE TROUGH TO 23N44W. SCATTERED SHOWERS AND ISOLATED MODERATE
CONVECTION COVER THE AREA FROM 20N-32N BETWEEN 35W-44W. THIS
ACTIVITY IS LARGELY ENHANCED BY THE UPPER LEVEL LOW CENTER. THE
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1030MB HIGH CENTERED E OF THE AZORES NEAR
37N16W.

$$
HUFFMAN



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