[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 23 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.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N7W 3N22W 1N34W 3N51W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM N...160 NM
S OF THE AXIS BETWEEN 24W-34W. SIMILAR ACTIVITY IS WITHIN 230 NM
N...180 NM S OF THE AXIS BETWEEN 36W-43W. SCATTERED MODERATE
CONVECTION IS ALSO FROM 4N-8N BETWEEN 41W-47W...AND FROM EQ-4N
BETWEEN 48W-51W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY ZONAL WLY FLOW ALOFT COVERS THE GULF OF MEXICO S OF AN
UPPER LEVEL RIDGE ACROSS THE MISSISSIPPI VALLEY AND GREAT
PLAINS. DRY AIR AND SUBSIDENCE IS PROVIDING MUCH OF THE BASIN
WITH GENERALLY FAIR WEATHER. HOWEVER...A WEAK COLD FRONT BISECTS
THE BASIN EXTENDING FROM S FLORIDA NEAR 26N82W TO 26N89W
CONTINUING AS A STATIONARY FRONT TO THE TEXAS COAST NEAR 28N97W
AND THEN ALONG THE TEXAS/MEXICO BORDER. LITTLE MOISTURE
ACCOMPANIES THE FRONT...AND THE ONLY SENSIBLE WEATHER IT IS
CAUSING IS AN AREA OF LOW CLOUDS FROM 24N-29N BETWEEN 86W-95W.
WEAK SURFACE RIDGING CENTERED OVER THE SRN MEXICAN COAST IS
PROVIDING FAIR WEATHER ACROSS THE SW GULF. EXPECT THE COLD FRONT
TO CONTINUE MOVING SE OUT OF THE AREA AS THE STATIONARY PORTION
DISSIPATES OVERNIGHT. A STRONGER COLD FRONT IS FORECAST TO MOVE
OFF THE TEXAS COAST EARLY SATURDAY.

CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE ALOFT THAT COVERS THE GULF OF MEXICO IS
ALSO IMPACTING MUCH OF THE WRN CARIBBEAN KEEPING CONDITIONS
FAIR. HOWEVER...ENHANCED AREAS OF MOISTURE ARE ACROSS THE SRN
AND ERN PORTIONS OF THE BASIN. A SURFACE TROUGH IS IN THE SW
CARIBBEAN ALONG 15N80W TO THE COLOMBIA COAST NEAR 9N77W. A 1013
MB LOW IS ANALYZED ALONG THE AXIS NEAR 12N79W. SURFACE
CONVERGENCE NEAR THE TROUGH/LOW IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 9N-15N BETWEEN 78W-83W. A
SECOND SURFACE TROUGH IS N OF VENEZUELA FROM 10N65W TO 15N70W
SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-16N
BETWEEN 65W-68W. ISOLATED SHOWERS ARE ALSO EMBEDDED IN THE
TRADEWIND FLOW FROM 13N-15N BETWEEN 68W-78W. FINALLY...A SURFACE
TROUGH...AN EXTENSION OF A COLD FRONT IN THE CENTRAL
ATLC...REACHES THE WINDWARD ISLANDS NEAR SAINT LUCIA AT 13N61W
TO 13N62W SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
FROM 11N-14N BETWEEN 61W-63W. EXPECT CONTINUED SHOWER ACTIVITY
ACROSS THE ERN CARIBBEAN OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
A BROAD DEEP LAYER TROUGH ANCHORED BY A 966 MB LOW SE OF
NEWFOUNDLAND NEAR 44N50W IS INFLUENCING MUCH OF THE WRN AND
CENTRAL ATLC. A COLD FRONT ASSOCIATED WITH THE SYSTEM ENTERS THE
SW N ATLC NEAR 32N64W CONTINUING SW TO THE SE FLORIDA COAST NEAR
26N80W. THE FRONT IS RELATIVELY DRY AND ONLY SUPPORTS ISOLATED
SHOWERS WITHIN 180 NM AHEAD OF THE FRONT E OF 76W. GALE FORCE
WINDS ARE EXPECTED N OF 27N E OF THE FRONT TO 53W BY 1800 UTC
TODAY. FARTHER E...A SECOND COLD FRONT ENTERS THE DISCUSSION
AREA NEAR 32N32W EXTENDING SW TO A 1013 MB LOW NEAR 17N55W
CONTINUING AS A SURFACE TROUGH TO THE WINDWARD ISLANDS NEAR
SAINT LUCIA. ISOLATED SHOWERS ARE WITHIN 120 NM AHEAD OF THE
FRONT. SE OF THE FRONTAL TROUGH...A SECOND SURFACE TROUGH IS
ALONG 12N57W TO 7N61W SUPPORTING ISOLATED SHOWERS WITHIN 45 NM
EITHER SIDE OF THE AXIS. THE REMAINDER OF THE ATLC IS UNDER A
BROAD UPPER LEVEL RIDGE EXTENDING FROM E OF THE LESSER ANTILLES
NEAR 10N49W WITH AXIS CONTINUING NE AND THEN N ALONG 45W. THE
UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1018 MB HIGH
N OF THE CANARY ISLANDS NEAR 36N17W.

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

$$
WALTON





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