[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU DEC 08 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS A PORTION OF AFRICA WITH THE
ITCZ AXIS ENTERING THE E TROPICAL ATLC NEAR 9N14W CONTINUING
ALONG 10N18W 6N33W TO 6N48W. SCATTERED MODERATE/STRONG
CONVECTION IS FROM 3N-6N BETWEEN 33W-38W. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-6N BETWEEN
27W-33W AND FROM 3N-6N BETWEEN 38W-41W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH COVERS THE E CONUS E OF THE MISSISSIPPI VALLEY
WITH NEAR ZONAL SW FLOW ALOFT DOMINATING THE GULF. THE UPPER
TROUGH IS SUPPORTING A COLD FRONT THAT ENTERS THE GULF AT
08/0300 UTC ACROSS S FLORIDA NEAR 26N81W TO 23N85W WHERE IT
BECOMES A DISSIPATING STATIONARY FRONT TO OVER THE W YUCATAN
PENINSULA NEAR MERIDA. BROKEN/OVERCAST LOW/MID CLOUDS WITH
SCATTERED SHOWERS ARE WITHIN 120 NM W OF THE COLD FRONT AND OVER
THE S GULF S OF 23N W OF 89W. CLEAR SKIES COVER THE NW GULF N OF
27N W OF 91W WITH COLD AIR STRATOCUMULUS CLOUDS DOTING THE
REMAINDER OF THE GULF WATERS. A SURFACE RIDGE IS W OF THE FRONT
WITH A 1027 MB HIGH OVER N MEXICO AND A 1028 MB HIGH ALONG THE
COAST OF MEXICO BETWEEN TAMPICO AND TUXPAN. COLD FRONT WILL MOVE
OUT OF THE GULF OVERNIGHT. HIGH PRESSURE WILL CONTINUE TO BUILD
OVER THE SE US THROUGH SUN ALLOWING SOME INCREASE IN WINDS AND
SEAS ACROSS THE GULF REGION.

CARIBBEAN SEA...
A NARROW UPPER TROUGH AXIS EXTENDS FROM AN UPPER LOW NE OF
PUERTO RICO INTO THE CARIBBEAN OVER HISPANIOLA TO THE TIP OF
NICARAGUA/HONDURAS. STRONG SUBSIDENCE AND DRY STABLE AIR COVERS
MOST OF THE CARIBBEAN EXCEPT SE OF A LINE FROM THE LEEWARD
ISLANDS NEAR 17N62W TO PANAMA/COSTA RICA BORDER WHERE THERE IS
MOIST TROPICAL AIR. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE IN THE MOIST SECTOR ACROSS THE SE CARIBBEAN
WHILE THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY FAIR
CONDITIONS AGAIN TONIGHT. COLD FRONT WILL MOVE INTO THE YUCATAN
CHANNEL OVERNIGHT THEN WILL STALL AND DISSIPATE OVER THE W
CARIBBEAN THROUGH THU FROM W CUBA TO BELIZE.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE E CONUS IS MOVING INTO THE W ATLC
SUPPORTING A COLD FRONT THAT AT 08/0300 UTC ENTERS THE W ATLC
NEAR 32N77W TO ACROSS S FLORIDA BETWEEN WEST PALM BEACH AND FORT
LAUDERDALE INTO THE GULF OF MEXICO. BROKEN/OVERCAST LOW/MID
CLOUDS WITH SCATTERED SHOWERS ARE WITHIN 120 NM W OF THE COLD
FRONT. A SURFACE RIDGE CONTINUES TO RETREAT EASTWARD AHEAD OF
THE ABOVE FRONT COVERING THE W INTO THE CENTRAL ATLC BETWEEN
50W-75W AND ANCHORED BY A 1023 MB HIGH ABOUT 230 NM E-NE OF
BERMUDA. A NARROWING UPPER RIDGE EXTENDS FROM W CUBA NEAR 23N80W
ACROSS THE BAHAMAS AND THE W ATLC TO BEYOND 32N68W COVERING THE
W ATLC NW OF AN UPPER TROUGH THAT EXTENDS FROM 27N55W THROUGH AN
UPPER LOW NE OF PUERTO RICO NEAR 22N63W INTO THE CARIBBEAN OVER
HISPANIOLA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN
60 NM OF LINE FROM 23N57W 21N63W TO 22N68W. MODERATE/STRONG
SUBSIDENCE AND DRY STABLE AIR COVERS THE REMAINDER OF THE W ATLC
W OF 60W TO THE W ATLC COLD FRONT GIVING THE AREA FAIR WEATHER
AGAIN TONIGHT. A SURFACE TROUGH IS ANALYZED ALONG THE W EDGE OF
AN UPPER RIDGE EXTENDING THROUGH 32N42W ALONG 25N49W TO A 1009
MB LOW NEAR 21N53W CONTINUING SW TO 14N61W IN THE LESSER
ANTILLES. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM
18N-23N BETWEEN 45W-53W. A BROAD LOW AMPLITUDE UPPER RIDGE IS
ALONG 48W FROM 10N-24N BETWEEN 35W-58W ENHANCING THE ACTIVITY
ASSOCIATED WITH THE ABOVE SURFACE TROUGH/LOW. A SURFACE RIDGE
DOMINATES THE E ATLC ANCHORED BY A 1033 MB HIGH E OF THE AZORES
OFF THE COAST OF PORTUGAL. W ATLC COLD FRONT WILL SHIFT SE AND
STALL FROM NEAR BERMUDA TO CENTRAL CUBA BY THU NIGHT THEN WILL
DRIFT WESTWARD SLOWLY FRI STALLING AGAIN FROM 31N75W TO S
FLORIDA BY LATE FRI BEFORE SETTLING FROM NEAR BERMUDA TO CENTRAL
FLORIDA BY LATE SUN AGAIN. THE 1009 MB LOW AND SURFACE TROUGH
WILL DISSIPATE THROUGH THU AS THE LOW WEAKENS AND SHIFTS W
ACROSS THE LEEWARDS THROUGH LATE FRI. A SECOND TROUGH WILL MOVE
W THROUGH THE LEEWARDS SAT AND SUN.



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

$$
PAW





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