[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251126
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE NOV 25 2008

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
1045 UTC.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 10N13W 6N22W 4N33W 4N40W 3N52W.
SCATTERED MODERATE CONVECTION IS FROM 3N-7N BETWEEN 22W-30W.

...DISCUSSION...

GULF OF MEXICO...
STRONG SOUTHWESTERLY AND WESTERLY UPPER LEVEL WINDS IN THE BASE
OF A DEEP TROUGH OVER THE E CONUS COVER THE GULF REGION...WITH
UPPER LEVEL MOISTURE STREAMING ACROSS THE GULF REGION. THIS
TROUGH IS SUPPORTING A SURFACE COLD FRONT ACROSS THE N AND W
GULF THAT EXTENDS FROM THE W FLORIDA PANHANDLE NEAR 30N86W TO
27N93W TO NE MEXICO NEAR 25N98W. ALSO...A SURFACE TROUGH IS
AROUND 60 NM TO THE E OF THE COLD FRONT BETWEEN THE FLORIDA
PANHANDLE AND 93W. LOW LEVEL CONVERGENCE NEAR THE SURFACE COLD
FRONT AND SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS N OF 26N E OF 93W. THIS ACTIVITY IS BEING
ENHANCED BY STRONG UPPER LEVEL DIVERGENCE IN THE SW QUADRANT OF
AN UPPER LEVEL JET. IN THE WAKE OF THE COLD FRONT...A
REINFORCING COOLER AND DRIER AIRMASS IS IN PLACE. THIS AIRMASS
IS BEING SUPPORTED BY A 1029 MB SURFACE HIGH OVER TEXAS NEAR
31N101W. DURING THE NEXT DAY...THE SURFACE COLD FRONT IS
EXPECTED TO MOVE SOUTHWARD ACROSS THE GULF REGION.
ADDITIONALLY...SUBSIDENCE IS INHIBITING DEEP CONVECTION IN THE
VICINITY OF A 1022 MB SURFACE HIGH OVER THE W FLORIDA PENINSULA
NEAR 27N82W. OVER THE S GULF...CONFLUENT FLOW ALOFT IS
INHIBITING DEEP CONVECTION. ADDITIONALLY...STRONG N TO NE
SURFACE WINDS ARE FORECAST TO BLOW THROUGH THE ISTHMUS OF
TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC
REGION BEGINNING AT 25/1500 UTC.

CARIBBEAN SEA...
IN THE SW CARIBBEAN...A 1008 MB SURFACE LOW IS CENTERED NEAR
11N82W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW IS
SUPPORTING NUMEROUS SHOWERS AND THUNDERSTORMS S OF 16N W OF 75W.
ANY FURTHER DEVELOPMENT OF THIS SYSTEM IS EXPECTED TO BE SLOW TO
OCCUR. AS THIS SYSTEM DRIFTS SLOWLY WEST-NORTHWESTWARD...IT WILL
LIKELY PRODUCE HEAVY RAINS AND LOCALIZED FLOODING OVER PORTIONS
OF PANAMA...COSTA RICA...NICARAGUA...AND EASTERN HONDURAS DURING
THE NEXT COUPLE OF DAYS. THE INCREASED SURFACE PRESSURE GRADIENT
ASSOCIATED WITH THE SURFACE LOW IS SUPPORTING N TO NE SURFACE
WINDS OF 20 TO 30 KT FOR LOCATIONS IN THE SW CARIBBEAN FROM
11N-15N W OF 75W. THE SHOWER AND THUNDERSTORM ACTIVITY
ASSOCIATED WITH THE SURFACE LOW IS BEING ENHANCED BY STRONG
UPPER LEVEL DIFFLUENCE IN THE VICINITY OF AN UPPER RIDGE PRESENT
OVER THE W CARIBBEAN...WITH THE AXIS OF THIS UPPER RIDGE
EXTENDING FROM N COLOMBIA NEAR 12N72W TO 18N82W TO THE NW
CARIBBEAN NEAR 21N85W. OVER THE E AND CENTRAL CARIBBEAN...UPPER
LEVEL DIVERGENCE IS COMBINING WITH DEEP MOISTURE TO GENERATE
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 14N BETWEEN
63W-71W.

ATLANTIC OCEAN...
A DEEP TROUGH OVER THE E CONUS CONTINUES TO APPROACH THE W
ATLC...WITH STRONG WESTERLY FLOW ALOFT OVER THE W ATLC. ALSO...
A SURFACE TROUGH E OF THE COAST OF THE SE CONUS EXTENDS FROM
28N79W TO 30N78W TO 32N77W TO N OF THE DISCUSSION AREA...WITH
SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THIS SURFACE
TROUGH. THE DEEP TROUGH IS SUPPORTING A COLD FRONT THAT
CURRENTLY EXTENDS FROM THE SE CONUS ACROSS THE N GULF. THIS COLD
FRONT IS FORECAST TO BEGIN TO MOVE ACROSS PORTIONS OF THE W ATLC
DURING THE NEXT DAY. IN THE WAKE OF THE COLD FRONT...A
REINFORCING COOLER AND DRIER AIRMASS IS IN PLACE. FARTHER
E...THE AXIS OF A SHARP UPPER TROUGH OVER THE CENTRAL ATLC
EXTENDS FROM 26N48W TO 32N55W TO NW OF THE DISCUSSION
AREA...WITH A 100 KT CYCLONICALLY-CURVED UPPER LEVEL JET
ROUNDING THE BASE OF THIS TROUGH. DEEP AND STRONG ASCENT
ORIGINATING FROM STRONG UPPER LEVEL DIVERGENCE IN THE NE
QUADRANT OF THIS JET IS PROVIDING THE UPPER SUPPORT FOR A
1002 MB SURFACE LOW NEAR 32N51W. THE CORRESPONDING STRONG
SURFACE PRESSURE GRADIENT AROUND THIS SURFACE LOW IS RESULTING
IN GALE FORCE SURFACE WINDS WITHIN 300 NM OF THE S SEMICIRCLE OF
THE SURFACE LOW. ALSO...A SURFACE COLD FRONT EXTENDS FROM SOUTH
OF THE SURFACE LOW FROM 32N51W TO 25N49W TO 20N52W. LOW LEVEL
CONVERGENCE IN THE VICINITY OF THIS SURFACE LOW AND SURFACE COLD
FRONT IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 26N
BETWEEN 41W-54W...WHICH ARE BEING ENHANCED BY UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THE AFOREMENTIONED CENTRAL ATLC UPPER
LEVEL JET. FARTHER TO THE SOUTH...A SURFACE TROUGH EXTENDS FROM
10N59W TO A 1009 MB SURFACE LOW NEAR 11N57W TO 14N51W...WITH
SCATTERED SHOWERS OCCURRING WITHIN 60 NM OF THE SURFACE LOW AND
SURFACE TROUGH. OVER THE E ATLC...AN UPPER TROUGH IS N OF 25N
BETWEEN 28W-36W...WITH AN UPPER LOW NEAR 35N34W. AN ASSOCIATED
SURFACE TROUGH EXTENDS FROM 28N37W TO A 1011 MB SURFACE LOW NEAR
26N32W TO 24N30W TO 22N33W. THE COMBINATION OF LOW LEVEL
CONVERGENCE ASSOCIATED WITH THE SURFACE LOW AND SURFACE
TROUGH...AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE UPPER
TROUGH...IS SUPPORTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS FROM 25N-29N BETWEEN 25W-34W.

$$
COHEN




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