[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 070557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 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 5N23W 5N35W TO 6N47W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM 2N-10N BETWEEN 32W-48W.
CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA WITHIN 90
NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 15N-32W.

...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 COLD
FRONT ENTERING THE GULF AT 07/0300 UTC OVER FORT WALTON BEACH
FLORIDA ALONG 28N88W TO 24N92W WHERE IT BECOMES STATIONARY TO
THE COAST OF S MEXICO NEAR 18N94W. BROKEN/OVERCAST LOW/MID
CLOUDS WITH SCATTERED SHOWERS COVER THE AREA W OF THE FRONT WITH
SKIES BEGINNING TO CLEAR ALONG THE TEXAS COAST. A SURFACE RIDGE
CONTINUES TO BUILD W OF THE FRONT WITH A 1031 MB HIGH OVER NE
MEXICO. SOUTHERLY FLOW IS E OF THE FRONT WITH ISOLATED SHOWERS
WITHIN 120 NM E OF THE FRONT N OF 27N AND WITHIN 75 NM E OF THE
FRONT BETWEEN 20N-26N. THE REMAINDER OF GULF IS DOMINATED BY AN
UPPER RIDGE ANCHORED OVER THE N YUCATAN PENINSULA EXTENDING AND
AXIS NE ACROSS EXTREME S FLORIDA INTO THE W ATLC. STRONG
SUBSIDENCE AND DRY STABLE AIR ARE COVER THE GULF SE OF A LINE
FROM APALACHICOLA BAY FLORIDA TO TUXPAN MEXICO WITH ACCOMPANYING
CLEAR SKIES. SLOW MOVING COLD FRONT WILL REACH FROM FLORIDA BIG
BEND TO E BAY OF CAMPECHE WED THEN MOVE SE OF THE AREA WED
NIGHT. GALE FORCE WINDS ARE EXPECTED BEHIND THE FRONT IN THE SW
GULF WED. SURFACE RIDGE WILL CONTINUE TO BUILD E ACROSS THE N
GULF THU.

CARIBBEAN SEA...
A NARROW UPPER TROUGH AXIS EXTENDS FROM AN UPPER LOW N OF PUERTO
RICO ALONG 16N68W THEN W TO NICARAGUA NEAR 13N83W. STRONG
SUBSIDENCE AND DRY STABLE AIR COVERS ALL BUT THE FAR SE
CARIBBEAN WHERE MOIST TROPICAL AIR IS SE OF LINE FROM THE
LEEWARD ISLANDS NEAR 17N62W TO VENEZUELA NEAR 11N68W. THE
MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA
NEAR 9N75W ALONG 10N80W INTO THE E PACIFIC REGION OVER
PANAMA/COSTA RICA NEAR 9N83W WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 45/60 NM ALONG THE COAST OF COLOMBIA AND E
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 TONIGHT.
A COLD FRONT WILL MOVE INTO THE YUCATAN CHANNEL WED NIGHT THEN
WILL STALL AND DISSIPATE OVER THE W CARIBBEAN THROUGH FRI.

ATLANTIC OCEAN...
THE UPPER RIDGE FROM THE GULF OF MEXICO EXTENDS AN AXIS ACROSS
EXTREME S FLORIDA INTO THE W ATLC TO BEYOND 32N70W COVERING THE
W ATLC W OF 70W. A SURFACE RIDGE REMAINS OVER THE W ATLC S OF
30N W OF 60W AND N OF 30N W OF 55W AND ANCHORED BY A 1025 MB
HIGH 200 NM N OF BERMUDA. AN UPPER LOW IS IN THE W/CENTRAL ATLC
CENTERED N OF PUERTO RICO NEAR 21N65W COVERING THE AREA BETWEEN
58W-70W AND EXTENDING A TROUGH AXIS S INTO THE CARIBBEAN WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM
19N-25N BETWEEN 63W-68W. MODERATE/STRONG SUBSIDENCE AND DRY
STABLE AIR COVERS THE REMAINDER OF THE W ATLC W OF 60W GIVING
THE AREA FAIR WEATHER AGAIN TONIGHT. A SURFACE TROUGH IS
ANALYZED TO THE E EXTENDING FROM 29N48W ALONG 24N50W THROUGH A
1008 MB LOW NEAR 10N55W CONTINUING S TO E OF BARBADOS NEAR
13N58W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM
20N-24N BETWEEN 50W-56W. A BROAD LOW AMPLITUDE UPPER RIDGE IS TO
THE E OF THE UPPER TROUGH ALONG 43W FROM 10N-30N ENHANCING THE
ACTIVITY ASSOCIATED WITH THE ABOVE SURFACE TROUGH/LOW AS WELL AS
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM
9N-13N BETWEEN 45W-58W. A SURFACE RIDGE DOMINATES THE E ATLC
ANCHORED BY A 1035 MB HIGH JUST N OF THE AZORES AND A 1034 MB
HIGH FURTHER E. SURFACE RIDGE OVER THE NW ATLC WILL WEAKEN AND
MOVE SE. A COLD FRONT WILL MOVE OFF THE FLORIDA COAST WED NIGHT
THEN FROM NEAR BERMUDA TO E CUBA THU NIGHT BEFORE STALLING AND
WEAKENING TO A TROUGH FRI. THIS TROUGH WILL MOVE W FRI THROUGH
SUN.

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

$$
PAW





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