[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED DEC 15 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 7N18W 4N30W 7N42W 4N52W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 210 NM S
OF THE ITCZ BETWEEN 15W-21W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH COVERS THE E GULF E OF 90W CONTINUING INTO
THE W ATLC WHILE ZONAL WESTERLY FLOW ALOFT DOMINATES THE
REMAINDER OF THE GULF. STRONG SUBSIDENCE AND DRY STABLE AIR
ALOFT CONTINUES TO DOMINATE THE ENTIRE GULF. THE SURFACE
RIDGE CONTINUES TO SHIFT EASTWARD AND IS NOW ANCHORED BY A 1021
MB HIGH OVER SW GEORGIA WITH A WEAK 1019 MB HIGH OVER S MEXICO
ABOUT 175 NM NW OF MEXICO CITY. COOL DRY AIR REMAINS OVER THE
FAR E GULF AND THE FLORIDA PENINSULA WHILE THE AIR OVER THE
REMAINDER OF THE GULF IS MODERATING AS SOUTHERLY RETURN FLOW IS
ALSO INCREASING OVER THE W GULF AND INCREASING THE SURFACE
WINDS. THIS SOUTHERLY FLOW IS ALSO RESPONSIBLE FOR OVERCAST LOW
CLOUDS WITH POSSIBLE ISOLATED SHOWERS N OF 26N TO OVER S
MISSISSIPPI AND SE LOUISIANA BETWEEN 88W-92W. THE SURFACE WINDS
WILL DIMINISH LATE THU AHEAD OF THE NEXT COLD FRONT TO ENTER THE
NW GULF EARLY FRI.

CARIBBEAN SEA...
A BROAD UPPER RIDGE ANCHORED IN THE W TROPICAL ATLC NEAR 11N55W
DOMINATES THE CARIBBEAN. TROPICAL MOISTURE REMAINS ACROSS THE
CARIBBEAN WITH THE REMNANTS OF A DISSIPATING STATIONARY FRONT
ENTERING THE CARIBBEAN FROM THE W/CENTRAL ATLC ACROSS THE VIRGIN
ISLANDS NEAR 18N65W EXTENDING ALONG 16N68W TO 16N72W THEN S TO
THE COAST OF COLOMBIA NEAR SANTA MARTA. ISOLATED SHOWERS ARE
POSSIBLE WITHIN 90 NM EITHER SIDE OF THE FRONTAL BOUNDARY.
BROKEN TO OVERCAST COLD AIR STRATOCUMULUS CLOUDS REMAIN OVER
PORTIONS OF THE NW CARIBBEAN WITH HIGH CIRRUS CLOUDS COVERING
THE CARIBBEAN SW OF A LINE FROM THE NW COAST OF HAITI TO THE
HONDURAS/NICARAGUA BORDER. A SURFACE TROUGH IS JUST OF THE
WINDWARD ISLANDS EXTENDING FROM 13N60W TO THE COAST OF VENEZUELA
NEAR 9N61W GIVING THE AREA SCATTERED SHOWERS FROM 9N-13N BETWEEN
60W-62W INCLUDING THE WINDWARD ISLANDS...TRINIDAD...AND TOBAGO.

ATLANTIC OCEAN...
THE SURFACE RIDGE COVERING THE GULF OF MEXICO AND ANCHORED OVER
SW GEORGIA COVERS THE FAR W ATLC W OF 75W. A BROAD DEEP LAYERED
TROUGH COVERS THE W ATLC W OF A LINE FROM CUBA NEAR 20N75W
25N58W TO BEYOND 32N49W SUPPORTING A COLD FRONT THAT ENTERS THE
CENTRAL ATLC NEAR 32N51W EXTENDING ALONG 25N53W TO 21N61W WHERE
IT PULLS UP STATIONARY TO OVER THE VIRGIN ISLANDS NEAR 18N65W
WHERE IT DISSIPATES OVER THE CARIBBEAN WATERS. ALSO ASSOCIATED
WITH THE UPPER TROUGH IS A JET STREAM WITH WINDS OF 85 TO 125 KT
COVERING THE AREA N OF 21N BETWEEN 53W-79W. THE BROAD UPPER
RIDGE ANCHORED IN THE W TROPICAL ATLC NEAR 11N55W EXTENDS A
RIDGE AXIS N ALONG 22N51W TO BEYOND 32N43W ENHANCING SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 200 NM E OF
THE COLD FRONT AND SCATTERED SHOWERS WITHIN 225 NM NW OF THE
REMAINDER OF THE FRONT S OF 26N. BROKEN/OVERCAST COLD AIR
STRATOCUMULUS CLOUDS ARE OVER THE REMAINDER OF THE W ATLC W OF
THE FRONT TO 80W. A WEAK SURFACE RIDGE REMAINS OVER THE
E/CENTRAL ATLC MOSTLY N OF THE REGION WITH A WEAK 1016 MB HIGH
NEAR 24N44W. A SECOND UPPER LEVEL TROUGH IS OVER THE E ATLC N OF
13N BETWEEN 35W AND THE COAST OF W AFRICA SUPPORTING A SECOND
COLD FRONT ENTERING THE E ATLC NEAR 32N18W EXTENDING ACROSS THE
WESTERN MOST CANARY ISLANDS ALONG 25N19W TO 22N21W DISSIPATING
TO NEAR 17N31W. SCATTERED SHOWERS ARE ASSOCIATED WITH A SURFACE
LOW CENTERED JUST N OF THE REGION NEAR 33N30W COVERING AN AREA N
OF 28N BETWEEN 22W-28W.

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

$$
PAW





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