[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251740
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI NOV 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1735 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS WRN AFRICA THROUGH GUINEA
ENTERING THE ATLC WATERS ALONG 10N14W QUICKLY ENDING AT 8N16W.
THE ITCZ AXIS EXTENDS FROM 8N16W ALONG 4N30W TO 8N50W. A SURFACE
TROUGH IS ANALYZED W OF THE ITCZ FROM 13N53W TO 7N55W WITH
ISOLATED MODERATE CONVECTION WITHIN 80-120 NM EITHER SIDE OF THE
TROUGH AXIS N OF 11N. SCATTERED MODERATE CONVECTION IS WITHIN
100-150 NM EITHER SIDE OF THE ITCZ BETWEEN 42W-51W AND E OF 32W.

...DISCUSSION...

GULF OF MEXICO...
A COOL AND DRY AIRMASS CONTINUES IN PLACE ACROSS MOST OF THE
GULF THIS AFTERNOON. SURFACE WINDS HAVE TURNED E AND SE DURING
THE OVERNIGHT HOURS AND THROUGHOUT THIS MORNING...N OF A
WEAKENING STATIONARY FRONT EXTENDING W ACROSS WRN CUBA INTO THE
SOUTH-CENTRAL GULF THEN S INTO THE BAY OF CAMPECHE ALONG 23N84W
24N90W 18N94W. THE UPPER ATMOSPHERE ACROSS THE GULF IS DOMINATED
BY VERY DRY AIR AND STRONG SUBSIDENCE HINDERING THE CONVECTION
IN THE VICINITY OF THE BOUNDARY. CURRENTLY...VISIBLE SATELLITE
IMAGERY SHOWS A FEW ISOLATED SHOWERS WITHIN 20 NM ON EITHER SIDE
OF THE BOUNDARY E OF 91W. LOW LEVEL STRATOCUMULUS CLOUDS
CONTINUE TO COVER MOST OF THE GULF N OF THE BOUNDARY. SURFACE
AND MARINE OBSERVATIONS INDICATE AN INCREASE IN WIND SPEED OVER
THE FAR SE BASIN...INCLUDING THE FLORIDA STRAITS. GUSTY EASTERLY
WINDS BETWEEN 20-25 KT AND OCCASIONALLY GUSTING TO 30 KT ARE
OBSERVED E OF 86W S OF 26N. THIS FLOW WILL CONTINUE TO SPREAD
ACROSS THE ERN BASIN OVER THE NEXT 24 HOURS AND TURN SOUTHERLY
AHEAD OF THE NEXT COLD FRONT EXPECTED TO ENTER THE NW GULF
WATERS SUNDAY MORNING.

CARIBBEAN SEA...
THE ATTENTION HAS TURNED TO THE SW CARIBBEAN WATERS THIS EARLY
AFTERNOON...AS A BROAD AREA OF CYCLONIC FLOW WITH SCATTERED
MODERATE CONVECTION EMBEDDED IN THE MONSOONAL GYRE APPEARS TO
SLOWLY BECOMING ORGANIZED. HEAVY SHOWERS AND THUNDERSTORMS ARE S
OF 16N W OF 71W. ALTHOUGH IT HAS BEEN DIFFICULT TO PIN DOWN A
SPECIFIC LOCATION FOR A LOW LEVEL CENTER...COMPUTER MODELS ARE
IN GOOD AGREEMENT OF A LOW PRESSURE SYSTEM DEVELOPING OVER THE
NEXT 24 HOURS IN THIS REGION. REGARDLESS OF DEVELOPMENT...A
BROAD AREA OF SCATTERED MODERATE TO STRONG CONVECTION WILL
REMAIN OVER THE SW AND SOUTH-CENTRAL BASINS FOR AT LEAST THE
NEXT 24 HOURS. AN AREA OF SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS IS S OF 16N BETWEEN 64W-71W. THIS AREA OF
CONVECTION IS MOVING WESTWARD AND INTO THE AREA OF ATTENTION.
A DRY UPPER ATMOSPHERE COVERS THE REST OF THE CARIBBEAN
SUPPRESSING DEEP CONVECTION ACROSS THE AREA. A SURFACE TROUGH
LOCATED ABOUT 400 NM ESE OF THE LESSER ANTILLES WILL BEGIN TO
AFFECT THIS GROUP OF ISLANDS S OF 16N WITHIN THE NEXT 12-18
HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH CONTINUES TO MOVE ACROSS THE WESTERN AND
CENTRAL N ATLC...SUPPORTING A COLD FRONT THAT ENTERS OUR REGION
ALONG 32N54W AND CONTINUES SW ALONG 26N65W ACROSS THE TURKS AND
CAICOS ISLANDS AND INTO CUBA ALONG 21N77W. VISIBLE SATELLITE
IMAGERY INDICATED SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITHIN 60 NM EITHER SIDE OF THE FRONT N OF 25N. A BROAD UPPER
RIDGE OF HIGH PRESSURE CURRENTLY MOVING ACROSS THE ERN CONUS
WILL ENTER THE WRN ATLC THIS AFTERNOON...AS THE COLD FRONT
CONTINUES TO TRACK EASTWARD. FARTHER AHEAD...AN ELONGATED UPPER
RIDGE SUPPORTS A 1020 MB HIGH OVER THE CENTRAL ATLC NEAR 30N42W
KEEPING FAIR WEATHER CONDITIONS ACROSS THIS AREA. TO THE NE OF
THIS LOW LEVEL HIGH CENTER...A NEARLY STATIONARY UPPER LEVEL
CUT-OFF LOW IS OVER THE ERN ATLC REFLECTING A SURFACE 1011 MB
LOW CENTERED NEAR 34N35W. A STATIONARY FRONT EXTENDS SE AND THEN
S FROM THE OCCLUSION POINT INTO OUR AREA ALONG 32N30W AND
CONTINUES SSW ALONG 25N31W TO 22N38W. SCATTERED WEAK SHOWERS ARE
WITHIN 70 NM ON EITHER SIDE OF THE FRONT.

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

$$

GARCIA




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