[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED DEC 22 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 FROM SIERRA LEONE NEAR 8N13W ALONG 6N20W
4N30W TO 4N49W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
ALONG THE AXIS WITHIN 75 NM EITHER SIDE BETWEEN 30W-43W. AN
EMBEDDED SURFACE TROUGH EXTENDS ALONG 12N51W TO 3N50W ENHANCED
BY MID TO UPPER LEVEL DIFFLUENCE. NUMEROUS MODERATE/ISOLATED
STRONG CONVECTION IS FROM 4N-11N BETWEEN 43W-55W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDING FROM THE W CENTRAL GULF OF MEXICO
NORTH ACROSS THE CENTRAL CONUS COMBINED WITH DRY AND SUBSIDENT
AIR ALOFT IS PROVIDING MOSTLY FAIR CONDITIONS THIS EVENING. THE
UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH
CENTERED NEAR 25N90W. THE ANTI-CYCLONIC FLOW AROUND THE RIDGE IS
WEAKENING DUE TO A WEAK COLD FRONT EXTENDING FROM E GEORGIA TO W
TEXAS APPROACHING THE GULF COAST. MAINLY CLEAR SKIES ARE ACROSS
THE BASIN WITH THE EXCEPTION OF AN AREA OF STRATOCUMULUS CLOUDS
IN THE N AND CENTRAL PORTIONS OF THE GULF AND CLOUD COVER ALONG
THE TEXAS AND LOUISIANA COAST DUE TO THE FRONT. THE WEAK COLD
FRONT IS FORECAST TO MOVE OFF THE COAST LATER TONIGHT FOLLOWED
BY A STRONGER FRONT MOVING OFF THE COAST LATE FRIDAY AND 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. MAINLY SWLY FLOW COVERS THE BASIN AROUND THE ERN HALF OF
AN UPPER LEVEL RIDGE CENTERED IN THE TROPICAL NORTH ATLC NEAR
10N50W. A SURFACE TROUGH IN THE SW CARIBBEAN EXTENDS FROM 14N78W
TO THE COAST OF COLOMBIA NEAR 10N76W. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE FROM 13N-16N BETWEEN 76W AND 79W. A
SHEAR LINE EXTENDS ALONG 13N66W TO 15N76W DELINEATING
CONVERGENCE OF 20 KT WINDS N OF THE LINE AND 10 KT WINDS S OF
THE LINE. SCATTERED MODERATED CONVECTION IS WITHIN 150 NM N OF
THE LINE. ANOTHER SURFACE TROUGH ENTERS THE E CARIBBEAN OVER
SAINT LUCIA NEAR 14N61W EXTENDING ALONG 13N63W TO THE COAST OF
VENEZUELA NEAR 10N66W. MODERATE CONVECTION IS WITHIN 75 NM N AND
W OF THE AXIS AND WITHIN 30 NM S AND E OF THE AXIS N OF 12N.
EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS THE CENTRAL AND
ERN CARIBBEAN OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
SURFACE RIDGING CENTERED OVER THE GULF OF MEXICO EXTENDS OVER
THE FAR W ATLC KEEPING CONDITIONS FAIR OVER THE BAHAMAS. A DEEP
LAYER TROUGH IS TO THE E SUPPORTING A BROAD LOW PRESSURE SYSTEM
CENTERED IN THE FAR NW ATLANTIC WITH AN ASSOCIATED COLD FRONT
ENTERING THE DISCUSSION AREA NEAR 32N39W CONTINUING ALONG 28N43W
TO 21N51W WHERE IS BECOMES DISSIPATING TO 17N60W. WHILE THE
FRONT REMAINS RELATIVELY INACTIVE CONVECTIVELY S OF 32N...
ISOLATED PRE-FRONTAL SHOWERS ARE OCCURRING WITHIN 30 NM EITHER
SIDE OF A LINE FROM 26N38W TO 23N44W. THIS AREA OF SHOWERS IS
MOST LIKELY ENHANCED BY THE MIDDLE TO UPPER LEVEL TROUGH AXIS
EXTENDING FROM 30N39W TO 20N50W. A SURFACE TROUGH IS S OF THE
FRONT ALONG 20N48W 14N57W TO SAINT LUCIA NEAR 14N61W. SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS ARE FROM 16N-20N BETWEEN 46W-54W.
ACROSS THE ERN ATLC...A BROAD UPPER LEVEL RIDGE EXTENDING FROM
THE TROPICAL NORTH ATLC NEAR 10N50W TO THE AZORES ISLANDS
SUPPORTS A SURFACE RIDGE ANCHORED BY A 1017 MB HIGH NEAR 27N30W
PROVIDING GENERALLY FAIR WEATHER ACROSS THIS PORTION OF THE
BASIN. AN UPPER LEVEL TROUGH TO THE E FROM THE IBERIAN PENINSULA
ACROSS NW AFRICA TO THE CAPE VERDE ISLANDS IS SUPPORTING A LOW
PRESSURE SYSTEM N OF THE DISCUSSION AREA THAT IS GENERATING
CYCLONIC SURFACE FLOW N OF 26N E OF 21W. A SURFACE TROUGH
DEPICTS THE SHIFTING CYCLONIC WINDS ENTERING THE AREA NEAR
32N11W EXTENDING TO 26N15W. THERE IS NO SIGNIFICANT CONVECTION
ASSOCIATED WITH THIS TROUGH.

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

$$
MONTALVO/HUFFMAN




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