000 AXNT20 KNHC 250536 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... THE TROPICAL WAVE THAT WAS OVER THE W CARIBBEAN ALONG 75W S OF 16N FOR THE 24/1800 UTC SURFACE ANALYSIS HAS BEEN ABSORBED BY THE BROAD LOW LEVEL CYCLONIC CIRCULATION ASSOCIATED WITH A 1007 MB SURFACE LOW IN THE SW CARIBBEAN NEAR 11N80W. THEREFORE...THIS WAVE NO LONGER APPEARS IN THE SURFACE ANALYSIS. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 10N14W 6N22W 5N33W 5N45W 4N53W. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 25W-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 N AND CENTRAL GULF REGION. THIS TROUGH IS SUPPORTING A SURFACE COLD FRONT ACROSS THE NW GULF THAT EXTENDS FROM S LOUISIANA NEAR 29N91W TO 28N94W TO S TEXAS NEAR 27N98W. TO THE E OF THE COLD FRONT...A SURFACE TROUGH EXTENDS FROM S LOUISIANA NEAR 29N90W TO 27N91W TO 26N92W. LOW LEVEL CONVERGENCE NEAR THE SURFACE COLD FRONT AND SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 27N BETWEEN 87W-93W. THIS ACTIVITY IS BEING ENHANCED BY STRONG UPPER LEVEL DIVERGENCE IN THE VICINITY OF AN UPPER LEVEL JET. IN THE WAKE OF THE COLD FRONT...A REINFORCING COOLER AND DRIER AIRMASS...CHARACTERIZED AS A MODIFIED CONTINENTAL POLAR AIRMASS...IS IN PLACE. THIS AIRMASS IS BEING SUPPORTED BY A 1028 MB SURFACE HIGH OVER N TEXAS NEAR 24N99W. DURING THE NEXT DAY...THE SURFACE COLD FRONT IS EXPECTED TO MOVE SOUTHWARD ACROSS THE CENTRAL AND E GULF REGION. ALSO... SUBSIDENCE IS INHIBITING DEEP CONVECTION IN THE VICINITY OF A 1023 MB SURFACE HIGH OVER THE FAR E GULF NEAR 29N64W. OVER THE S GULF...DEEP LAYER DRY AIR 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 25/1800 UTC. CARIBBEAN SEA... IN THE SW CARIBBEAN...A 1007 MB SURFACE LOW IS CENTERED NEAR 11N80W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW IS SUPPORTING NUMEROUS SHOWERS AND THUNDERSTORMS S OF 16N W OF 75W. THERE ARE NO SIGNS OF TROPICAL CYCLONE FORMATION...AND ANY FURTHER DEVELOPMENT IS EXPECTED TO BE SLOW TO OCCUR. AS THIS SYSTEM DRIFTS SLOWLY WESTWARD...IT WILL LIKELY PRODUCE HEAVY RAINS AND LOCALIZED FLOODING OVER PORTIONS OF PANAMA...COSTA RICA...AND NICARAGUA 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 12N-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 11N72W TO 14N80W TO THE NW CARIBBEAN NEAR 20N85W. OVER THE E AND CENTRAL CARIBBEAN...UPPER LEVEL DIVERGENCE IS COMBINING WITH DEEP MOISTURE TO GENERATE SCATTERED SHOWERS S OF 14N BETWEEN 63W-70W. ATLANTIC OCEAN... A DEEP UPPER TROUGH OVER THE E CONUS CONTINUES TO APPROACH THE W ATLC...WITH ATMOSPHERIC LIFT IN INCREASING SOUTHWESTERLY FLOW ALOFT OCCURRING ACROSS THE W ATLC. THIS LIFT IS BEING ENHANCED BY LOW LEVEL CONVERGENCE ASSOCIATED WITH A SURFACE TROUGH E OF THE SE CONUS THAT EXTENDS FROM 33N78W TO 30N79W TO 28N79W...WITH SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THIS SURFACE TROUGH. THE DEEP UPPER TROUGH IS SUPPORTING A COLD FRONT THAT CURRENTLY EXTENDS FROM THE SE CONUS ACROSS THE NW 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 VIGOROUS UPPER TROUGH OVER THE CENTRAL ATLC EXTENDS FROM 27N52W TO 32N55W TO NW OF THE DISCUSSION AREA...WITH A 110 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 1006 MB SURFACE LOW NEAR 31N51W. THE CORRESPONDING STRONG SURFACE PRESSURE GRADIENT AROUND THIS SURFACE LOW IS RESULTING IN GALE FORCE SURFACE WINDS WITHIN 240 NM OF THE SW QUADRANT OF THE SURFACE LOW. ALSO...A SURFACE COLD FRONT EXTENDS FROM SOUTH OF THE SURFACE LOW FROM 31N51W TO 25N51W TO 19N55W...WITH A SURFACE WARM FRONT EXTENDING NORTHEAST OF THE SURFACE LOW FROM 31N51W TO 32N51W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IN THE VICINITY OF THIS SURFACE LOW AND THESE SURFACE FRONTS IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 24N BETWEEN 42W-54W...WHICH ARE BEING ENHANCED BY UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE AFOREMENTIONED UPPER LEVEL JET. FARTHER TO THE SOUTH...A SURFACE TROUGH EXTENDS FROM A 1010 MB SURFACE LOW NEAR 12N58W TO 14N55W TO 16N50W...WITH ISOLATED SHOWERS OCCURRING WITHIN 60 NM OF THE SURFACE LOW AND SURFACE TROUGH. OVER THE E ATLC...AN UPPER TROUGH IS N OF 24N BETWEEN 24W-40W. AN ASSOCIATED SURFACE TROUGH EXTENDS FROM 28N36W TO A 1011 MB SURFACE LOW NEAR 27N32W TO 21N33W. 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 22N-29N BETWEEN 25W-35W. $$ COHEN