[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081138
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 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 11N16W CONTINUING
ALONG 7N27W TO 5N45W. SCATTERED MODERATE/STRONG CONVECTION IS
FROM 2N-7N BETWEEN 30W-36W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM 3N-6N BETWEEN 36W-44W.
ISOLATED CLUSTERS OF SCATTERED MODERATE CONVECTION ARE 3N-8N
BETWEEN 19W-30W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH COVERS THE US 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 STRAITS OF
FLORIDA AT 08/0900 UTC NEAR 24N80W THEN ACROSS CUBA NEAR HAVANA
INTO THE W CARIBBEAN. SCATTERED SHOWERS ARE WITHIN 75 NM W OF
THE FRONT. BROKEN/OVERCAST LOW/MID CLOUDS WITH ISOLATED SHOWERS
ARE OVER THE S GULF S OF 24N W OF 91W TO INLAND OVER MEXICO.
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 1028 MB HIGH NEAR HOUSTON
TEXAS AND A SECOND 1028 MB HIGH NEAR JACKSON MISSISSIPPI. COLD
FRONT WILL MOVE COMPLETELY OUT OF THE GULF IN THE NEXT FEW
HOURS. 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...
THE COLD FRONT IN THE W ATLC EXTENDS THROUGH THE STRAITS OF
FLORIDA ACROSS CUBA NEAR HAVANA TO 21N85W WHERE IT DISSIPATES TO
ALONG THE COAST OF BELIZE TO 16N88W IN THE GULF OF HONDURAS.
ISOLATED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE FRONT. 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 MOIST TROPICAL AIR IS SE OF A LINE FROM THE
LEEWARD ISLANDS NEAR 17N62W TO THE COSTA RICA/NICARAGUA BORDER.
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE IN THE
MOIST SECTOR ACROSS THE S CARIBBEAN WHILE THE REMAINDER OF THE
CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS AGAIN THIS MORNING.
COLD FRONT WILL STALL AND DISSIPATE OVER THE W CARIBBEAN FROM W
CUBA TO GULF OF HONDURAS THROUGH TONIGHT.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE E US CONUS CONTINUES TO MOVE FURTHER E
OVER THE W ATLC SUPPORTING A COLD FRONT THAT AT 08/0900 UTC
ENTERS THE W ATLC NEAR 32N74W TO THROUGH THE STRAITS OF FLORIDA
NEAR 24N80W. ISOLATED SHOWERS ARE WITHIN 120 NM W OF THE COLD
FRONT. A SURFACE RIDGE E OF THE FRONT IS NARROWING IN RESPONSE
TO THE FRONT TO THE W AND THE LOW/SURFACE TROUGH TO THE E AND
NOW COVERS THE AREA N OF 24N BETWEEN 50W-70W ANCHORED BY A 1022
MB HIGH ABOUT 375 NM E-NE OF BERMUDA. A NARROWING UPPER RIDGE
EXTENDS FROM W CUBA NEAR 23N80W ACROSS THE BAHAMAS AND THE W
ATLC TO BEYOND 28N70W COVERING THE W ATLC NW OF AN UPPER TROUGH
THAT EXTENDS FROM 27N56W THROUGH AN ELONGATING UPPER LOW NE OF
PUERTO RICO NEAR 23N63W INTO THE CARIBBEAN OVER HISPANIOLA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF
LINE FROM 22N59W 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 THIS MORNING.
A SURFACE TROUGH IS ANALYZED ALONG THE W EDGE OF AN UPPER RIDGE
EXTENDING THROUGH 32N41W ALONG 25N45W TO A 1009 MB LOW NEAR
21N54W CONTINUING SW ALONG 15N57W TO 11N60W JUST E OF TRINIDAD.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 150/180 NM
SE OF THE TROUGH BETWEEN 16N-24N. A SURFACE RIDGE DOMINATES THE
E ATLC ANCHORED BY A 1034 MB HIGH INLAND OVER SPAIN. W ATLC COLD
FRONT WILL SHIFT E AND STALL FROM NEAR BERMUDA TO CENTRAL CUBA
BY TONIGHT. THIS FRONTAL BOUNDARY WILL THEN DRIFT SLOWLY
WESTWARD FRI AND SAT THEN DISSIPATE. A TROUGH MAY ENTER FROM THE
CENTRAL ATLC SUN INTO MON.

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

$$
PAW





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