[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 04 2010

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 09N13W 06N20W 06N40W 05N48W. A
SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ AND ANALYZED FROM
02N-10N ALONG 50W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 02N-10N BETWEEN 41W-48W EAST OF THE SURFACE
TROUGH WHILE LOW-LEVEL CONVERGENCE WEST OF THE SURFACE TROUGH IS
GENERATING ISOLATED MODERATE CONVECTION FROM 03N-09N BETWEEN
48W-55W.

...DISCUSSION...

GULF OF MEXICO...
CONFLUENT FLOW ALOFT OVER THE GULF IS LEADING TO WIDESPREAD
SUBSIDENCE IN SUPPORT OF A BROAD 1022 MB HIGH CENTERED NEAR
26N90W. THIS SURFACE HIGH IS PROVIDING THE ENTIRE GULF WITH FAIR
CONDITIONS AND MOSTLY CLEAR SKIES THIS AFTERNOON. THROUGH THE
WEEKEND...AS THE HIGH SHIFTS SOUTHWARD AND WEAKENS SLIGHTLY...A
COLD FRONT CURRENTLY INLAND OVER CENTRAL TEXAS WILL BEGIN TO
IMPACT THE GULF COAST AND NORTHERN GULF WATERS EARLY SUNDAY. BY
LATE SUNDAY...N TO NE WINDS BEHIND THE FRONT WILL SPREAD
SOUTHWARD AS THE FRONT SHIFTS EASTWARD INTO THE W ATLC AND NW
CARIBBEAN SEA.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH CONTINUES TO SWEEP ACROSS THE W ATLC AND
INTRODUCE VERY DRY AIR ALOFT OVER THE WESTERN CARIBBEAN W OF
75W. FURTHERMORE...CONFLUENCE ALOFT ALONG 20N SUPPORTS
SUBSIDENCE AND THE EXTENSION OF SURFACE RIDGING FROM THE GULF OF
MEXICO TO NW OF A LINE FROM THE WINDWARD PASSAGE TO EASTERN
HONDURAS PROVIDING GENERALLY FAIR CONDITIONS. HOWEVER...A FEW
ISOLATED SHOWERS ARE OCCURRING FROM 16N-19N BETWEEN 84W-87W.
FARTHER EAST...THE UPPER LEVEL TROUGH ALSO SUPPORTS A COLD FRONT
ANALYZED FROM HISPANIOLA NEAR 20N70W TO 18N75W THEN CONTINUES AS
A SHEAR LINE ALONG 17N80W TO 14N83W. ISOLATED SHOWERS ARE
OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONTAL BOUNDARY WHILE
CONVERGENT NE AND E TRADES ARE FOCUSING MOISTURE AND ISOLATED
SHOWERS WITHIN 90 NM EITHER SIDE OF THE SHEAR LINE. THE
REMAINDER OF THE CARIBBEAN E OF 75W IS UNDER THE INFLUENCE OF
UPPER LEVEL RIDGING CENTERED IN THE TROPICAL ATLC NEAR 10N50W.
THE ASSOCIATED UPPER LEVEL DIFFLUENT ENVIRONMENT IS ENHANCING
SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE SE CARIBBEAN S OF
15N E OF 72W...INCLUDING THE ABC ISLANDS...NW VENEZUELA...AND
THE WINDWARD ISLANDS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS LOCATED OVER THE W ATLC WITH AXIS
EXTENDING FROM 32N65W TO 23N76W. THIS UPPER LEVEL FEATURE
SUPPORTS A PRIMARY COLD FRONT ANALYZED FROM 32N57W SW ALONG
26N60W TO NORTH OF HISPANIOLA NEAR 20N70W. ISOLATED SHOWERS ARE
OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT. TO THE NW...A
SECONDARY COLD FRONT EXTENDS FROM A 1001 MB LOW CENTERED NEAR
36N63W TO 30N68W. WHILE OVERALL STABLE CONDITIONS CONVECTIVELY
EXIST W OF THE PRIMARY FRONT TO 81W...EARLY MORNING
SCATTEROMETER PASSES DEPICTED A STRONG NORTHWESTERLY WIND FIELD
REACHING UP TO 25 KT N OF 26N. BY EARLY SUNDAY...GALE FORCE
CONDITIONS ARE EXPECTED N OF 30N BETWEEN 68W AND 78W. OVER THE
EASTERN ATLC...UPPER LEVEL TROUGHING IS ALONG 26W DIPPING
SOUTHWARD TO 20N. THIS TROUGHING SUPPORTS A 983 MB LOW CENTERED
NORTH OF THE AREA NEAR 37N28W AND A PAIR OF COLD FRONTS. THE
MAIN COLD FRONT IS ANALYZED ALONG 32N27W 28N30W TO 23N40W...
WHILE A DISSIPATING COLD FRONT IS ALONG 32N21W TO 22N29W. LITTLE
SIGNIFICANT DEEP CONVECTION IS NOTED WITH EITHER FRONT...
HOWEVER...NW TO W WINDS REMAIN IN THE 20-30 KT RANGE N OF 24N
BETWEEN 20W-35W.

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

$$
HUFFMAN/MONTALVO




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