[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131137 AAA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT NOV 13 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0615 UTC.

...SPECIAL FEATURES...

A 1009 MB LOW IS LOCATED IN THE SW CARIBBEAN SEA CENTERED NEAR
11N77W THAT CONTINUES TO PRODUCE AN AREA OF UNORGANIZED WIDELY
SCATTERED MODERATE CONVECTION COVERING THE AREA S OF 16N BETWEEN
71W-80W. AS THIS AREA OF DISTURBED WEATHER HAS SLOWLY MOVED
WESTWARD OVER THE PAST COUPLE OF DAYS...IT CONTINUES TO LOCATE
ITSELF BENEATH AN UPPER LEVEL RIDGE ACROSS THE WESTERN CARIBBEAN
SEA AND PORTIONS OF CENTRAL AMERICA. THIS IS PROVIDING AN UPPER
LEVEL DIFFLUENT ENVIRONMENT FOR THE ONGOING CONVECTION.
CONDITIONS APPEAR FAVORABLE FOR SLOW DEVELOPMENT OVER THE NEXT
COUPLE OF DAYS AS THE SYSTEM DRIFTS WEST-NORTHWESTWARD. THERE IS
A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 6N11W
WESTWARD ALONG 3N20W 4N30W 6N40W 9N50W. A SURFACE TROUGH IS
ANALYZED WITHIN THE ITCZ FROM 12N34W TO 4N38W. WEAK LOW-LEVEL
CYCLONIC FLOW IS IN THE VICINITY OF THE SURFACE TROUGH AXIS.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2N TO
8N BETWEEN 27W AND 35W. THIS AREA OF CONVECTION CONTINUES TO BE
ENHANCED BY AN UPPER LEVEL TROUGH WITH AXIS ALONG 30W AND A BASE
VERY NEAR THE ONGOING CONVECTION. ELSEWHERE...ISOLATED MODERATE
CONVECTION IS WITHIN 150 NM ON EITHER SIDE OF THE ITCZ W 20W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A MID-UPPER LEVEL RIDGE OF HIGH
PRESSURE COVERING THE GULF...EXTENDING FROM SOUTHERN MEXICO
NORTHWARD TO OVER THE SE CONUS. THIS FEATURE SUPPORTS SURFACE
RIDGING AND LIGHT ANTI-CYCLONIC FLOW ACROSS THE AREA.
THUS...MOSTLY FAIR WEATHER CONDITIONS PERSIST THIS MORNING.
HOWEVER...SOUTHERLY RETURN FLOW IS INCREASING OVER THE NW GULF
DUE TO A COLD FRONT CURRENTLY EMERGING OFF THE TEXAS COAST. THIS
FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH/SHORTWAVE MOVING
ACROSS THE MIDWEST. DOPPLER RADAR IMAGERY DEPICTS THE LINE OF
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH THE
FRONT FROM GALVESTON ISLAND TO CORPUS CHRISTI. COMPUTER MODELS
SUGGEST THIS FRONT WILL CONTINUE TO MOVE ACROSS THE NW BASIN
OVER THE NEXT 12 HOURS WITH CONVECTION AHEAD OF IT AND NORTHERLY
GUSTY WINDS BEHIND IT AFFECTING MOSTLY THE COAST OF TEXAS.

CARIBBEAN SEA...
THE SPECIAL FEATURE 1009 MB LOW OVER THE FAR SW CARIBBEAN SEA
CONTINUES GENERATING SCATTERED SHOWERS AND TSTMS S OF 16N
BETWEEN 71W-80W. THE BASE OF A BROAD UPPER LEVEL TROUGH DEEPS
DOWN OVER THE NORTH CENTRAL CARIBBEAN EXHIBITING OVERALL DRY AIR
ALOFT ON WATER VAPOR IMAGERY. THIS UPPER LEVEL TROUGHING
SUPPORTS A RATHER WEAK COLD FRONT THAT ENTERS THE BASIN OVER
WESTERN HAITI AND EXTENDS SW TO S OF JAMAICA NEAR 17N77W.
THEN...A REMNANT CLOUD/SHEAR LINE CONTINUES TO NEAR 13N81W. NO
DEEP CONVECTION IS OBSERVED IN THE VICINITY OF THE FRONT...NOR
THE SHEAR LINE. ON THE OTHER HAND...LINGERING CONVECTION IS
OBSERVED OVER THE FAR NE BASIN S OF PUERTO RICO FROM A PREVIOUS
FRONTAL SYSTEM NOW OVER THE ATLC BASIN. FAIR WEATHER CONDITIONS
ARE ELSEWHERE ACROSS THE DISCUSSION AREA...ESPECIALLY OVER THE
NW BASIN DUE TO A DRY AND SUBSIDENT AIRMASS NOTICED ON WATER
VAPOR IMAGERY...ASSOCIATED TO AN UPPER LEVEL RIDGE AXIS
EXTENDING FROM NORTHERN COLOMBIA TO SOUTHERN MEXICO.

ATLANTIC OCEAN...
AN OCCLUDED DEEP LAYERED 999 MB GALE FORCE LOW REMAINS SPINNING
OVER THE WESTERN NORTH ATLC CENTERED NEAR 34N62W. THIS SYSTEM IS
SUPPORTED BY THE MIDDLE TO UPPER LEVEL TROUGHING THAT DIPS WELL
INTO THE NORTH-CENTRAL CARIBBEAN SEA. AS A UPPER LEVEL SHORTWAVE
TROUGH ROTATES AROUND THE MAIN DEEP LAYERED LOW...A COLD FRONT
ENTERS THE DISCUSSION AREA NEAR 32N54W AND EXTENDS SW ALONG
25N58W 21N63W TO THE DOMINICAN REPUBLIC NEAR 19N70W WITH NO DEEP
CONVECTION. THE BROAD UPPER LEVEL TROUGHING ALSO SUPPORTS A 1009
MB LOW CENTERED NEAR 32N47W. A NEARLY STATIONARY FRONT EXTENDS
SW FROM THE EASTERN SEMI-CIRCLE OF THE LOW CENTER TO THE FAR NE
CARIBBEAN ALONG 26N50W 22N57W 16N62W. SCATTERED SHOWERS ARE
WITHIN 100 NM ON EITHER SIDE OF THE STATIONARY FRONT BETWEEN 48W
AND 58W. FARTHER EAST...THE REMAINDER OF THE EASTERN ATLC IS
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1020 MB
HIGH CENTERED NEAR 28N24W...EXTENDING RIDGE AXIS TO JUST EAST OF
THE LEEWARD ISLANDS NEAR 17N58W.

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

$$

GARCIA



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