[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 250001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE NOV 24 2009

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 8N12W 6N25W 8N40W 7N50W 8N60W.
AN EMBEDDED SURFACE TROUGH IS ALONG THE ITCZ AXIS FROM 16N40W TO
6N42W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS E OF THE
TROUGH AXIS FROM 1N-8N BETWEEN 21W-37W. ISOLATED MODERATE
CONVECTION IS ALONG THE TROUGH AXIS..AND E OF THE AXIS FROM
8N-17N BETWEEN 27W-37W. AN UPPER LEVEL TROUGH WITH AXIS ALONG
42W IS PROVIDING A DIFFLUENT ZONE ALOFT WHICH IS ENHANCING THE
LARGE AREA OF CONVECTION E OF THE SURFACE TROUGH AND ALONG THE
ITCZ AXIS.

...DISCUSSION...

GULF OF MEXICO...
A LARGE AREA OF ACTIVE WEATHER REMAINS ACROSS THE WRN GULF OF
MEXICO TONIGHT. AS OF 2100 UTC...A COLD FRONT EXTENDS OFF THE
TEXAS COAST STRETCHING FROM 30N93W NEAR LAKE CHARLES LOUISIANA
TO 25N98W S OF BROWNSVILLE TEXAS CONTINUING NW ALONG THE SIERRA
MADRE MOUNTAINS TO NEAR 27N102W. RECENT LIGHTNING AND RADAR DATA
INDICATE NUMEROUS SHOWERS/THUNDERSTORMS JUST S OF BROWNSVILLE IN
THE NERN TIP OF MEXICO FROM 24N-26N BETWEEN 97W-100W. LIGHTNING
DATA ALSO INDICATES ACTIVE THUNDERSTORMS S OF THE CENTRAL
LOUISIANA COAST FROM 26N-29N BETWEEN 91W-93W. SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS COVER MOST OF THE N AND CENTRAL
GULF FROM 25N-29N BETWEEN 88W-96W. A STATIONARY FRONT IS AHEAD
OF THIS LARGE AREA OF SHOWER ACTIVITY EXTENDING FROM CENTRAL
FLORIDA ENTERING THE GULF OF MEXICO AT 27N82W N OF FORT MYERS
CONTINUING INTO THE CENTRAL GULF ALONG 26N87W 23N94W. LIGHTNING
DATA INDICATES NUMEROUS SHOWERS/THUNDERSTORMS ALONG THE SRN
PORTION OF THE FRONT FROM 22N-25N BETWEEN 90W-94W. SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS ARE ALSO WITHIN 60 NM OF THE
FRONT AXIS. THIS ENTIRE SYSTEM IS SUPPORTED BY A LONGWAVE UPPER
LEVEL TROUGH OVER THE CENTRAL CONUS WITH AXIS EXTENDING SWD OVER
THE FAR WRN GULF. SIGNIFICANT UPPER LEVEL MOISTURE ALONG WITH
DIFFLUENT FLOW ALOFT AROUND THE ERN SIDE OF THE UPPER TROUGH IS
ACROSS THE BASIN SUPPORTING THE LARGE AREA OF SHOWER ACTIVITY.
SURFACE WINDS OF 20-25 KT ARE BEHIND THE COLD FRONT. EXPECT
SHOWERS/THUNDERSTORMS TO CONTINUE OVER THE MAJORITY OF THE GULF
AS THE COLD FRONT PUSHES SE.

CARIBBEAN SEA...
SUBSIDENCE AND DRY AIR REMAINS ACROSS THE MAJORITY OF THE
CARIBBEAN SEA NOTED IN WATER VAPOR IMAGERY SUPPORTING FAIR
WEATHER ACROSS MUCH OF THE BASIN. A FEW ISOLATED
SHOWERS/POSSIBLE THUNDERSTORMS ARE ACROSS THE YUCATAN PENINSULA
AND WRN CUBA ASSOCIATED WITH MOIST AND DIFFLUENT WSW FLOW ALOFT
BETWEEN AN UPPER LEVEL TROUGH OVER THE CENTRAL CONUS AND WRN
GULF AND AN UPPER LEVEL RIDGE COVERING THE CARIBBEAN EXTENDING
INTO THE WRN ATLC. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO
ACROSS THE SW CARIBBEAN S OF 13N BETWEEN 78W-85W AFFECTING MOST
OF PANAMA...COSTA RICA...AND ERN NICARAGUA ENHANCED BY SURFACE
CONVERGENCE NEAR THE E PACIFIC ITCZ. A FEW ISOLATED SHOWERS ARE
NOTED OVER JAMAICA...CENTRAL HISPANIOLA...AND THE FAR SW
CARIBBEAN. FRESH TO STRONG TRADEWINDS ARE ACROSS THE MAJORITY OF
THE BASIN WITH THE STRONGEST WINDS OFF THE COAST OF COLOMBIA.
EXPECT LITTLE CHANGE OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
A STATIONARY FRONT EXTENDS ACROSS THE WRN ATLC FROM 31N73W ALONG
29N76W TO THE CENTRAL FLORIDA COAST AT 28N80W NEAR MELBOURNE
CONTINUING INTO THE GULF OF MEXICO. SCATTERED
SHOWERS/THUNDERSTORMS ARE JUST OFF THE FLORIDA COAST FROM
28N-29N BETWEEN 77W-82W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS
ARE ACROSS THE WRN ATLC N OF 22N W OF 68W. THIS ACTIVITY IS
SUPPORTED BY A MOIST AIR MASS EXTENDING FROM THE GULF OF MEXICO
AROUND AN UPPER LEVEL RIDGE STRETCHING FROM THE CENTRAL
CARIBBEAN TO THE NE UNITED STATES COASTLINE NEAR 37N75W. IN THE
CENTRAL ATLC...A 1011 MB LOW IS ANALYZED NEAR 27N54W. A SURFACE
TROUGH EXTENDS TO THE SW FROM THE LOW CENTER TO NEAR 22N59W. A
SECOND SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO THE NE
ALONG 28N47W TO A SECOND 1012 MB LOW CENTER NEAR 32N41W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 250 NM S OF
THIS TROUGH AXIS. TO THE N..A DYING COLD FRONT EXTENDS FROM THE
1012 MB LOW CENTER AT 32N41W TO 29N50W CONTINUING AS A DYING
STATIONARY FRONT TO 32N63W. ISOLATED SHOWERS ARE ALONG THIS
FRONT AXIS. A NARROW SHORTWAVE UPPER LEVEL TROUGH WITH AXIS
ALONG 36N65W 26N52W SUPPORTS THE 1011 MB LOW...WHILE A SECOND
LONGER WAVE UPPER LEVEL TROUGH CENTERED NEAR 22N42W SUPPORTS THE
1012 MB LOW AND THE SURFACE TROUGH CONNECTING THE TWO SURFACE
LOWS. THE LONGWAVE UPPER LEVEL TROUGH IS ALSO ENHANCING SHOWER
ACTIVITY ALONG THE ERN HALF OF THE ITCZ.

$$
WALTON






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