[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071135
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED DEC 07 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS A PORTION OF AFRICA WITH THE
ITCZ AXIS ENTERING THE E TROPICAL ATLC NEAR 7N12W CONTINUING
ALONG 7N17W 4N27W 6N43W TO SOUTH AMERICA NEAR 4N52W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 120 NM
EITHER SIDE OF THE ITCZ AXIS BETWEEN 30W-47W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH COVERS THE E CONUS FROM THE PLAIN STATES ACROSS
THE MISSISSIPPI VALLEY AND OVER THE NW GULF SUPPORTING A SLOW
MOVING COLD FRONT THAT ENTERS THE GULF AT 07/0900 UTC OVER
APALACHICOLA BAY FLORIDA ALONG 26N89W TO 21N92W TO THE COAST OF
S MEXICO NEAR 18N93W WITH SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ALONG THE FRONTAL BOUNDARY. BROKEN/OVERCAST
MULTILAYERED CLOUDS WITH SCATTERED SHOWERS COVER THE AREA W OF
THE FRONT WITH SKIES CLEARING W OF A LINE FROM LOUISIANA NEAR
30N93W TO MEXICO NEAR 25N97W. A SURFACE RIDGE IS W OF THE FRONT
WITH A 1031 MB HIGH OVER THE RIO GRANDE NW OF LAREDO TEXAS. THE
REMAINDER OF GULF IS DOMINATED BY AN UPPER RIDGE ANCHORED OVER
THE NE YUCATAN PENINSULA EXTENDING AND AXIS NE THROUGH THE
STRAITS OF FLORIDA INTO THE W ATLC. STRONG SUBSIDENCE AND DRY
STABLE AIR COVER THE GULF SE OF A LINE FROM PANAMA CITY FLORIDA
TO TAMPICO MEXICO WITH MOSTLY CLEAR SKIES E OF THE FRONT. COLD
FRONT WILL REACH FROM FLORIDA BIG BEND TO E BAY OF CAMPECHE THIS
MORNING THEN MOVE SE OF THE AREA TONIGHT. SHORT LIVED GALE FORCE
WINDS ARE EXPECTED BEHIND THE FRONT IN THE SW GULF LATER THIS
MORNING. SURFACE RIDGE WILL REMAIN ACROSS THE N GULF THROUGH
THU.

CARIBBEAN SEA...
A NARROW UPPER TROUGH AXIS EXTENDS FROM AN UPPER LOW NE OF
PUERTO RICO NEAR 21N63W INTO THE CARIBBEAN ALONG 15N70W THEN W
TO NICARAGUA NEAR 14N84W. STRONG SUBSIDENCE AND DRY STABLE AIR
COVERS ALL BUT THE FAR SE CARIBBEAN WHERE MOIST TROPICAL AIR IS
SE OF LINE FROM GUADELOUPE IN THE LEEWARD ISLANDS TO THE ABC
ISLANDS OFF THE COAST OF VENEZUELA. THE MONSOON TROUGH EXTENDS
FROM COLOMBIA S OF E PANAMA THEN OVER W PANAMA AND COSTA RICA
INTO THE E PACIFIC REGION NEAR 9N84W WITH SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 75 NM ALONG THE COAST OF COLOMBIA
FROM 75W TO PANAMA. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE IN THE MOIST SECTOR OF THE SE CARIBBEAN WHILE
THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS
AGAIN THIS MORNING. COLD FRONT WILL MOVE INTO THE YUCATAN
CHANNEL TONIGHT THEN WILL STALL AND DISSIPATE OVER THE W
CARIBBEAN THROUGH FRI.

ATLANTIC OCEAN...
THE UPPER RIDGE FROM THE GULF OF MEXICO EXTENDS AN AXIS THROUGH
THE STRAITS OF FLORIDA INTO THE W ATLC TO BEYOND 32N70W COVERING
THE W ATLC W OF 65W AND NW OF AN UPPER LOW NE OF PUERTO RICO. A
SURFACE RIDGE REMAINS OVER THE W ATLC W OF 56W AND ANCHORED BY A
1024 MB HIGH ABOUT 230 NM N-NE OF BERMUDA. AN UPPER LOW IS IN
THE W/CENTRAL ATLC CENTERED NE OF PUERTO RICO NEAR 21N63W
COVERING THE AREA S OF 26N BETWEEN 58W-72W AND EXTENDING A
TROUGH AXIS S INTO THE CARIBBEAN WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 22N-24N BETWEEN 60W-65W. MODERATE/STRONG
SUBSIDENCE AND DRY STABLE AIR COVERS THE REMAINDER OF THE W ATLC
W OF 60W GIVING THE AREA FAIR WEATHER AGAIN THIS MORNING. A
SURFACE TROUGH IS ANALYZED TO THE E EXTENDING FROM 30N46W ALONG
24N52W THROUGH A 1008 MB LOW NEAR 18N57W CONTINUING S TO 14N58W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 20N-25N
BETWEEN 47W-55W. A BROAD LOW AMPLITUDE UPPER RIDGE IS TO THE E
OF THE UPPER TROUGH ALONG 42W FROM 10N-31N BETWEEN 30W-58W
ENHANCING THE ACTIVITY ASSOCIATED WITH THE ABOVE SURFACE
TROUGH/LOW AS WELL AS CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION FROM 9N-13N BETWEEN 44W-59W. A SURFACE RIDGE
DOMINATES THE E ATLC ANCHORED BY A 1033 MB HIGH N OF THE AZORES
AND A 1034 MB HIGH E OF THE AZORES. SURFACE RIDGE OVER THE NW
ATLC WILL WEAKEN AND MOVE E. A COLD FRONT WILL MOVE OFF THE
FLORIDA COAST TONIGHT THEN FROM NEAR BERMUDA TO CENTRAL CUBA THU
MORNING WHERE IT WILL STALL AND WEAKEN TO A TROUGH THROUGH FRI.
THIS TROUGH WILL THEN DRIFT W FRI THROUGH SUN. THE 1008 MB LOW
CENTERED ALONG A TROUGH OVER THE CENTRAL AND W TROPICAL ATLC
WILL DRIFT E THEN DISSIPATE BY FRI NIGHT. THE SURFACE TROUGH
WILL THEN DRIFT BACK W TOWARD THE LEEWARD ISLANDS OVER THE
WEEKEND.

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

$$
PAW






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