000 AXNT20 KNHC 272337 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN NOV 27 2011 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2330 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF GUINEA NEAR 11N15W QUICKLY ENDING AT 9N18W. THE ITCZ CONTINUES FROM 9N18W ALONG 5N28W TO 7N41W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE ITCZ BETWEEN 20W-40W. ...DISCUSSION... GULF OF MEXICO... A FAIRLY STRONG COLD FRONT MOVES ACROSS THE CENTRAL GULF THIS EVENING. THIS FRONT IS ANALYZED ENTERING THE GULF ACROSS THE FLORIDA PANHANDLE ALONG 30N86W TO 24N89W INTO SOUTHERN MEXICO ALONG 19N91W. A STRONG N TO S SURFACE PRESSURE GRADIENT IS IN ITS WAKE...GENERATING NORTHERLY GALE FORCE WINDS WITH HIGHER GUSTS S OF 26N W OF THE FRONT. DOPPLER RADAR IMAGERY INDICATES SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 50 NM ON EITHER SIDE OF THE FRONT. THIS FRONTAL SYSTEM IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH MOVING ACROSS THE CENTRAL CONUS. THE FAR ERN GULF IS STILL UNDER FAIR CONDITIONS INFLUENCED BY DRY AIR ALOFT AND SURFACE RIDGING AROUND A 1026 MB HIGH IN THE W ATLC. THE FRONT IS EXPECTED TO CONTINUE PUSHING EWD ACROSS THE BASIN REACHING FLORIDA BY MONDAY. THE WINDS BEHIND THE FRONT ARE EXPECTED TO DECREASE BELOW GALE FORCE CRITERIA DURING THE NEXT 12 HOURS. CARIBBEAN SEA... DRY AIR ALOFT AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY ACROSS THE WNW CARIBBEAN NW OF A LINE EXTENDING FROM 17N71W TO 11N84W...PROVIDING FAIR CONDITIONS WITH A FEW ISOLATED SHOWERS SCATTERED SHOWERS AND THUNDERSTORMS ARE IN THE SOUTH CENTRAL CARIBBEAN S OF 15N BETWEEN 70W-80W ASSOCIATED WITH THE MONSOON TROUGH EXTENDING FROM THE COSTA RICA TO NRN COLOMBIA. THE ERN CARIBBEAN IS IMPACTED BY BROAD CYCLONIC FLOW AROUND A SURFACE TROUGH EXTENDING FROM 18N64W TO 13N67W. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES HIGH DEEP LAYER MOISTURE VALUES OVER THIS AREA...AS WELL AS IN THE SOUTH CENTRAL BASIN. SCATTERED SHOWERS AND THUNDERSTORMS ARE N OF 13N E OF 68W INCLUDING THE LESSER ANTILLES. SOME AREAS HAVE RECEIVED BETWEEN 2 AND 3 INCHES OVER THE PAST 24 HOURS WITH THE POTENTIAL OF FLOODING. MOIST CONDITIONS ARE EXPECTED TO REMAIN OVER THE ERN CARIBBEAN FOR THE NEXT COUPLE OF DAYS. THE FRONT CURRENTLY IN THE GULF OF MEXICO IS EXPECTED TO BEGIN IMPACTING THE NW CARIBBEAN WITHIN THE NEXT 24 HOURS. ATLANTIC OCEAN... SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 36N67W IS MAINTAINING FAIR CONDITIONS OVER THE W ATLC. AN UPPER LEVEL TROUGH MOVING ACROSS THE NORTH CENTRAL ATLC SUPPORTS A WEAK STATIONARY FRONT THAT ENTERS OUR DISCUSSION AREA AS A SURFACE TROUGH ALONG 32N54W TO 27N60W. MOSTLY DRY AIR ACCOMPANIES THE UPPER TROUGH WHICH IS INHIBITING SHOWER ACTIVITY NEAR THE TROUGH AXIS. TO THE E AND SE OF THIS FRONTAL BOUNDARY...UPPER LEVEL DIFFLUENCE IS SUPPORTING A SWATH OF SHOWERS AND THUNDERSTORMS WITHIN 140 NM ON EITHER SIDE OF A LINE EXTENDING FROM 18N64W TO 30N47W. AN EARLIER ASCAT PASS REVEALED A SURFACE TROUGH EMBEDDED WITHIN THIS REGION OF CONVECTION FROM 25N56W TO 19N59W. FARTHER E...A WEAK 1017 MB LOW IS CENTERED NEAR 31N38W CAUSING NO ACTIVE WEATHER. THE REMAINDER OF THE ERN ATLC IS DOMINATED BY A BROAD SURFACE RIDGE AROUND A 1030 MB HIGH N OF THE DISCUSSION AREA NEAR 38N19W PROVIDING MOSTLY FAIR WEATHER E OF 44W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA