[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED NOV 18 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 9N13W 8N25W 6N37W 9N47 10N56W.
ISOLATED MODERATE/STRONG CONVECTION IS FROM 6N-9N BETWEEN
26W-32W. A SURFACE TROUGH IS ANALYZED WITHIN THE AXIS FROM
13N49W TO 7N48W. ISOLATED MODERATE/STRONG CONVECTION IS SHEARED
E OF THE TROUGH AXIS FROM 9N-13N BETWEEN 45W-48W. A SECOND
SURFACE TROUGH IS ANALYZED FROM 15N59W TO 8N57W WITH SCATTERED
MODERATE/STRONG CONVECTION TO THE E OF THE AXIS FROM 11N-15N
BETWEEN 51W-58W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A STATIONARY FRONT EXTENDS FROM GEORGIA THROUGH
THE BIG BEND OF FLORIDA ENTERING THE GULF OF MEXICO NEAR 29N83W
CONTINUING ALONG 25N85W TO THE YUCATAN PENINSULA NEAR 21N89W
LINING THE MEXICO COASTLINE ALONG 19N91W 18N95W. ISOLATED
SHOWERS ARE POSSIBLE ALONG THE FRONT AXIS N OF 22N. SCATTERED
SHOWERS ARE OVER THE BAY OF CAMPECHE S OF 21N BETWEEN 90W-97W.
AN UPPER LEVEL TROUGH EXTENDS ACROSS THE ERN CONUS AND OVER THE
GULF OF MEXICO SUPPORTING THE FRONTAL SYSTEM. MODERATELY DRY AIR
BUILDS BEHIND THE FRONT NOTED ON WATER VAPOR IMAGERY. THIS DRY
AIR IS PROVIDING GENERALLY FAIR WEATHER AND CLEAR SKIES ACROSS
THE NW GULF. SURFACE WINDS UP TO 20 KTS ARE BEHIND THE FRONT IN
THE BAY OF CAMPECHE. EXPECT THE FRONT TO WEAKEN THROUGHOUT THE
EVENING AS HIGH PRESSURE BUILDS ACROSS THE NW GULF.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER
UNDER THE INFLUENCE OF DRY AIR AND SUBSIDENCE ASSOCIATED WITH AN
UPPER LEVEL RIDGE COVERING MUCH OF THE CARIBBEAN EXTENDING FROM
HONDURAS ACROSS ERN CUBA AND INTO THE WRN ATLC. SCATTERED
SHOWERS/THUNDERSTORMS ARE IN THE SW CARIBBEAN AFFECTING PORTIONS
OF COSTA RICA/PANAMA S OF 10N BETWEEN 76W-82W DUE TO SURFACE
CONVERGENCE NEAR THE E PACIFIC ITCZ. A FEW ISOLATED
SHOWERS/POSSIBLE THUNDERSTORMS ARE NOTED OVER PUERTO RICO
INDICATED BY RADAR DATA. MODERATE TRADE WINDS ARE ACROSS MUCH OF
THE BASIN WITH HIGHER WINDS NEAR THE COAST OF COLOMBIA. EXPECT
LITTLE CHANGE OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
LOW PRESSURE CONTINUES OVER THE W/CENTRAL ATLC CENTERED AT A
1012 MB LOW NEAR 26N63W. A SURFACE TROUGH EXTENDS FROM THE LOW
CENTER ALONG 23N66W 21N70W. A SECOND SURFACE TROUGH EXTENDS TO
THE E ALONG 28N54W 25N55W 22N56W. SCATTERED
SHOWERS/THUNDERSTORMS ARE W OF THE TROUGH FROM 20N-29N BETWEEN
53W-59W. THIS LARGE AREA OF CONVECTIVE ACTIVITY IS MORE ENHANCED
BY DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH CENTERED
NEAR 27N62W EXTENDING TO JUST E OF THE NRN LESSER ANTILLES AND
AN UPPER LEVEL RIDGE TO THE E WITH AXIS ALONG 48W. THE UPPER
LEVEL LOW CONTINUES TO SUPPORT THE SURFACE LOW. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO FARTHER E FROM 23N-28N BETWEEN
46W-49W. ACROSS THE ERN ATLC...A BROAD SURFACE RIDGE DOMINATES
ANCHORED BY A 1023 MB HIGH NEAR 30N26 SUPPORTING GENERALLY FAIR
WEATHER ACROSS THE AREA. IN THE UPPER LEVELS...A LONGWAVE UPPER
LEVEL TROUGH EXTENDS FROM THE NE ATLC ACROSS PORTUGAL TO THE
CANARY ISLANDS NEAR 28N16W ACROSS THE CAPE VERDE ISLANDS NEAR
17N25W TO NEAR 11N33W. AN UPPER LEVEL JET ALONG THE E SIDE OF
THIS UPPER TROUGH IS SHEARING MOISTURE FROM THE ITCZ TO THE NE
ENHANCING A LINE OF CLOUDS AND POSSIBLE SHOWERS FROM 11N29W TO
28N6W.

$$
WALTON





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