[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231704
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON NOV 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N11W 6N23W 8N32W 5N40W 7N52W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-9N
BETWEEN 23W-32W E OF AN EMBEDDED SURFACE TROUGH ALONG 14N34W
5N30W. ISOLATE MODERATE CONVECTION IS FROM 6N-8N BETWEEN
44W-53W. A SECOND EMBEDDED SURFACE TROUGH IS E OF THE LESSER
ANTILLES FROM 16N55W TO 6N54W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A SURFACE TROUGH EXTENDS ACROSS CENTRAL FLORIDA
ENTERING THE GULF OF MEXICO NEAR FORT MYERS CONTINUING ALONG
25N86W 23N92W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE
WITHIN 150 NM SE OF THE TROUGH AXIS...AND WITHIN 200 NM NW OF
THE AXIS. SCATTERED SHOWERS/THUNDERSTORMS ARE ALONG THE END OF
THE TROUGH AXIS IN THE WRN GULF FROM 22N-25N BETWEEN 90W-96W.
THE SHOWER ACTIVITY IS ALSO SUPPORTED BY MOIST SWLY FLOW ALOFT
AROUND THE ERN EDGE OF AN UPPER LEVEL TROUGH OVER THE CENTRAL
CONUS. A SURFACE RIDGE BUILDS ACROSS THE NRN GULF ANCHORED BY A
1021 MB HIGH S OF LOUISIANA NEAR 29N91W BRINING GENERALLY FAIR
WEATHER TO THE NW GULF COASTLINE. EXPECT THE SURFACE TROUGH TO
WEAKEN AS HIGH PRESSURE MOVES EASTWARD AHEAD OF THE NEXT COLD
FRONT FORECAST TO MOVE OFF THE TEXAS COAST TUE.

CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE IS ACROSS THE CARIBBEAN NOTED IN WATER
VAPOR IMAGERY SUPPORTING FAIR WEATHER ACROSS MUCH OF THE BASIN.
A FEW SHOWERS/THUNDERSTORMS ARE E OF THE YUCATAN PENINSULA FROM
16N-20N BETWEEN 85W-88W ASSOCIATED WITH A SHORTWAVE UPPER LEVEL
TROUGH EXTENDING DOWN THE ERN YUCATAN PENINSULA COAST. ISOLATED
SHOWERS/THUNDERSTORMS ARE ALSO NOTED N OF JAMAICA NEAR 19N78W.
SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE SW CARIBBEAN S OF
12N BETWEEN 77W-84W AFFECTING AREAS OF PANAMA AND COSTA RICA.
THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR THE E
PACIFIC ITCZ...AS WELL AS DIFFLUENT FLOW ALOFT BETWEEN AN UPPER
LEVEL TROUGH IN THE E PACIFIC AND A BROAD UPPER LEVEL RIDGE THAT
COVERS THE CARIBBEAN. FRESH TO STRONG TRADEWINDS ARE ACROSS MUCH
OF THE BASIN. EXPECT LITTLE CHANGE OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
AS OF 1500 UTC...A WEAK 1018 MB SURFACE LOW IS CENTERED E OF THE
NRN COAST OF FLORIDA NEAR 31N77W. A SURFACE TROUGH EXTENDS FROM
THE LOW CENTER TO THE CENTRAL FLORIDA COAST NEAR VERO BEACH AT
28N80W CONTINUING INTO THE GULF OF MEXICO. SCATTERED
SHOWERS/THUNDERSTORMS ARE E OF THE TROUGH AXIS N OF 29N BETWEEN
72W-77W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS COVER THE AREA
N OF 24N W OF 72W. THIS SHOWER ACTIVITY IS SUPPORTED BY MOIST
SWLY AND DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH OVER
THE CENTRAL CONUS AND GULF OF MEXICO AND A BROAD UPPER LEVEL
RIDGE COVERING THE WRN ATLC EXTENDING FROM THE CENTRAL
CARIBBEAN. A WEAK SURFACE RIDGE AROUND A 1020 MB HIGH NEAR
26N68W COVERS THE REMAINDER OF THE WRN ATLC. A PAIR OF SURFACE
TROUGHS ARE IN THE CENTRAL ATLC. THE FIRST EXTENDS FROM 30N56W
TO 26N57W. ISOLATED SHOWERS ARE TO THE E OF THE AXIS FROM
25N-29N BETWEEN 51W-55W. THE SECOND TROUGH EXTENDS FROM 31N45W
TO 27N49W. STRONG SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM OF THE
TROUGH AXIS. BOTH SURFACE TROUGHS ARE SUPPORTED BY A NARROW
SHORTWAVE UPPER LEVEL TROUGH WITH AXIS ALONG 50W. AN UPPER LEVEL
LOW IS TO THE SE OF THE UPPER TROUGH CENTERED NEAR 23N41W. THE
UPPER LOW IS SUPPORTING AN AREA OF CLOUDINESS AND POSSIBLE
ISOLATED SHOWERS FROM 12N-24N BETWEEN 30W-39W. THE REMAINDER OF
THE ERN ATLC IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A
1034 MB HIGH N OF THE DISCUSSION AREA NEAR 38N18W.

$$
WALTON



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