[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN DEC 12 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
1745 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 5N9W
CONTINUING WEST ALONG 3N20W 6N29W 6N32W 5N40W 3N51W. A SURFACE
TROUGH IS EMBEDDED WITHIN THE ITCZ AXIS ALONG 31W S OF 12N.
SCATTERED MODERATE CONVECTION IS FROM 2N TO 8N BETWEEN 28W AND
48W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS ACROSS THE GULF FROM NORTHERN FLORIDA NEAR
30N83W TO TAMPICO MEXICO NEAR 21N97W ALONG 24N90W. A PRE-FRONTAL
TROUGH ASSOCIATED WITH STRONG SHOWERS AND THUNDERSTORMS IS 40 NM
AHEAD OF THE FRONT N OF 27N. SCATTERED SHOWERS ARE ALSO WITHIN
20 NM EITHER SIDE OF THE FRONT S OF 27N. THE SYSTEM IS SUPPORTED
BY AN UPPER LEVEL LONGWAVE/DEEP LAYER TROUGH OVER THE EASTERN
CONUS. GALE FORCE WINDS ARE NOTED BEHIND THE FRONT...AS WELL AS
STRONG SUBSIDENCE AND CLEARING NOTED ON WATER VAPOR AND
SATELLITE IMAGERY. THIS IS PROVIDING THE REMAINDER OF THE BASIN
MOSTLY FAIR WEATHER CONDITIONS. EXPECT THE FRONT TO CONTINUE TO
RACE ACROSS THE GULF AND REACH SOUTHERN FLORIDA LATE TONIGHT.

CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE COVER THE BASIN...KEEPING MUCH OF THE
CARIBBEAN UNDER FAIR CONDITIONS THIS AFTERNOON. HOWEVER...A
SHEARLINE EXTENDS FROM THE SW TIP OF HAITI NEAR 18N74W TO THE SW
BASIN ALONG 16N79W 11N80W. THE AXIS DEPICTS A LINE OF SURFACE
CONVERGENCE BETWEEN N-NE WINDS ACROSS THE NW CARIBBEAN AND TRADE
WINDS ACROSS THE REMAINDER OF THE BASIN. THE SURFACE CONVERGENCE
IS SUPPORTING ISOLATED SHOWERS WITHIN 40 NM EITHER SIDE OF THE
AXIS N OF 15N. THE ACTIVITY IS EXPECTED TO CONTINUE OVER THE
NEXT 24 HOURS...WITH NORTHERLY WINDS INCREASING IN THE NW BASIN
AHEAD OF THE COLD FRONT THAT IS MOVING ACROSS THE GULF OF
MEXICO. THE FRONT SHOULD REACH THE NW CARIBBEAN LATE TONIGHT.

ATLANTIC OCEAN...
DRY AIR AND STRONG SUBSIDENCE COVER THE WESTERN ATLC W OF 56W.
HOWEVER...CONDITIONS IN THE FAR WESTERN ATLC ARE EXPECTED TO
DETERIORATE AS A COLD FRONT ENTERS THE BASIN WITH STRONG SHOWERS
AND THUNDERSTORMS...AS WELL AS GALE FORCE WINDS IN THE WAKE OF
ITS PATH. DESPITE THE LACK OF UPPER LEVEL SUPPORT...A SURFACE
TROUGH EXTENDS ALONG 30N55W 26N61W 21N64W...CONTINUING AS A
SHEAR LINE TO 17N67W. NO DEEP CONVECTION IS PRESENT IN THE
VICINITY OF THE TROUGH AND SHEAR AXIS. A SECOND SURFACE TROUGH
IS TO THE SE ALONG 26N57W 22N56W 18N58W WITH ISOLATED SHOWERS
WITHIN 30 NM OF THE AXIS. TO THE E OF THIS BOUNDARY...SCATTERED
SHOWERS ARE FROM 21N TO 27N BETWEEN 42W AND 54W ASSOCIATED WITH
AN UPPER LEVEL JET IN THE ZONAL WLY FLOW ALOFT. THE REMAINDER OF
THE E ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A WEAK
1019 MB HIGH NEAR 25N40W. A COLD FRONT CLIPS THE DISCUSSION AREA
N OF THE RIDGE ALONG 32N28W 29N36W 28N45W. SCATTERED SHOWERS ARE
WITHIN 70 NM EAST OF THE AXIS N OF 29N.

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

$$

GARCIA



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