[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010559
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU DEC 01 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 AFRICA NOT REACHING THE COAST.
THE ITCZ ENTERS THE E TROPICAL ATLC NEAR 12N16W EXTENDING ALONG
8N21W 8N37W TO SOUTH AMERICA NEAR 7N59W. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE FROM 3N-8N BETWEEN 17W-28W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 7N-12N
BETWEEN 26W-35W.

...DISCUSSION...

GULF OF MEXICO...
ANOTHER UPPER TROUGH IS MOVING ACROSS THE N GULF N OF 27N WITH
ZONAL WESTERLY FLOW ALOFT PREVAILING ACROSS THE REMAINDER OF THE
GULF. DRY STABLE AIR AND STRONG SUBSIDENCE CONTINUES TO DOMINATE
THE AREA WITH PATCHES OF SCATTERED COLD AIR STRATOCUMULUS CLOUDS
OVER THE E GULF E OF 87W. CLEAR SKIES ARE OVER THE REMAINDER OF
THE GULF. A SURFACE RIDGE COVERS THE GULF ANCHORED BY A 1023 MB
HIGH OVER KENTUCKY. SURFACE RIDGE WILL PERSIST THROUGH SAT. A
COLD FRONT WILL MOVE INTO THE NW GULF LATE SUN WITH GALE
CONDITIONS EXPECTED W OF THE FRONT IN SW GULF BY LATE MON.

CARIBBEAN SEA...
A WEAKENING STATIONARY FRONT REMAINS EXTENDING FROM THE W ATLC
INTO THE W CARIBBEAN AT 01/0300 UTC ACROSS CUBA NEAR CABO CRUZ
JUST W OF JAMAICA TO THE COAST OF COSTA RICA NEAR THE PANAMA
BORDER. ISOLATED SHOWERS ARE POSSIBLE S OF 15N W OF THE
FRONT TO THE COAST OF NICARAGUA AND INLAND OVER COSTA RICA. AN
UPPER RIDGE DOMINATES THE NW CARIBBEAN W OF 70W WHILE A NARROW
UPPER TROUGH FROM THE W/CENTRAL ATLC EXTENDS S ACROSS THE VIRGIN
ISLANDS TO THE ABC ISLANDS. DRY STABLE AIR ALOFT AND STRONG
SUBSIDENCE COVERS ALL BUT THE FAR SE CARIBBEAN. THE MONSOON
TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 10N75W
ALONG 10N80W TO ACROSS PANAMA/COSTA RICA INTO THE E PACIFIC
REGION NEAR 9N82W AND IS GENERATING ISOLATED SHOWERS INLAND AND
WITHIN 60/75 NM ALONG THE COAST OF COLOMBIA. A SURFACE TROUGH IS
JUST E OF LESSER ANTILLES BUT CONTINUES TO GENERATE ISOLATED
SHOWERS E OF A LINE FROM DOMINICA ISLAND TO THE COAST OF
VENEZUELA TO OVER THE WINDWARD ISLANDS. THIS IS LEAVING THE
CENTRAL CARIBBEAN WITH FAIR WEATHER AGAIN TONIGHT. STATIONARY
FRONT WILL DISSIPATE LATER TODAY.

ATLANTIC OCEAN...
AN UPPER TROUGH IS MOVING INTO THE W ATLC W OF 77W RE-INFORCING
THE COLD AIR OVER THE SE CONUS. A COLD FRONT REMAINS ACROSS THE
W ATLC SUPPORTED BY AN UPPER TROUGH WELL N OF THE DISCUSSION
AREA AND ENTERS THE REGION AT 01/0300 UTC NEAR 32N68W ALONG
26N73W ACROSS THE S BAHAMA ISLANDS TO CUBA NEAR SAINT LUCIA
WHERE IT BECOMES STATIONARY AS IT CONTINUES INTO THE CARIBBEAN.
ISOLATED SHOWERS ARE WITHIN 75 NM W OF THE FRONT. A NARROWING
UPPER TROUGH IS IN THE W/CENTRAL ATLC EXTENDING A AXIS FROM
32N65W SE ALONG 25N57W THEN SW ACROSS THE VIRGIN ISLANDS INTO
THE CARIBBEAN SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM A
1005 MB SURFACE LOW NEAR 27N60W S TO 15N60W THEN BETWEEN
BARBADOS AND THE REMAINDER OF THE WINDWARD ISLANDS TO NW
TRINIDAD. DRY STABLE AIR IS W OF THE SURFACE TROUGH WITH MOSTLY
CLEAR SKIES BETWEEN THE SURFACE TROUGH AND THE W ATLC FRONT. A
NARROW HIGH AMPLITUDE UPPER RIDGE IS TO THE E OF THE UPPER
TROUGH EXTENDING AN AXIS FROM THE W TROPICAL ATLC NEAR 13N46W
ALONG 26N52W TO 33N58W PROVIDING DIFFLUENCE ALOFT TO GENERATE
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90
NM OF LINE FROM THE TROPICS NEAR 8N46W 13N55W THEN N TO 20N56W.
DENSE CLOUD COVER WITH POSSIBLE ISOLATED SHOWERS ARE WITHIN
150/200 NM OF LINE FROM 20N54W 28N54W TO BEYOND 32N60W. AN UPPER
TROUGH DIPS S OVER THE E ATLC N OF 20N E OF 35W SUPPORTING A
COLD FRONT THAT ENTERS THE REGION NEAR 32N25W TO 28N34W.
SCATTERED SHOWERS ARE WITHIN 30/45 NM SE OF THE FRONT. THE
REMAINDER OF THE E ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1035 MB HIGH ABOUT 650 NM W-NW OF THE AZORES. THE WEAKENING
W ATLC COLD FRONT WILL CONTINUES EASTWARD AND ABSORB THE
W/CENTRAL ATLC TROUGH AS THE 1005 MB LOW WILL MOVE RAPIDLY
NORTHWARD. A SURFACE RIDGE WILL BUILD BEHIND THE FRONT THROUGH
SUN.

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

$$
PAW





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