000 AXNT20 KNHC 201746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU OCT 20 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1735 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM NEAR 17N38W TO 8N48W MOVING W AT 5-8 KT. WAVE IS WELL DEFINED IN THE LOW LEVEL CLOUD FIELD AND IS EMBEDDED WITHIN A DEEP SURGE OF MOISTURE DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. A MID LEVEL CYCLONIC CIRCULATION IS OBSERVED OVER THE SRN EXTENSION OF THE WAVE AXIS...AND SHORT RANGE COMPUTER MODELS SUGGEST THIS MID LEVEL CIRCULATION COULD REACH SURFACE LEVEL OVER THE NEXT 6-12 HOURS...WITH NO CHANCES OF FURTHER DEVELOPMENT. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE WITHIN 150-190 NM ON EITHER SIDE OF THE WAVE AXIS. THE TROPICAL WAVE THAT WAS MOVING ACROSS THE NE WATERS OF SOUTH AMERICA OVER THE PAST FEW DAYS HAS LOST SOME OF ITS WAVE QUALITIES AND STRUCTURE...WITH VERY LITTLE WESTWARD PROGRESSION. THEREFORE...A TROUGH AXIS HAS REPLACED THE WAVE...ANALYZED FORM 13N54W TO 6N55W. DESPITE THE DOWNGRADE OF THIS WAVE...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 130 NM ON EITHER SIDE OF THE AXIS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS SW TO 9N20W TO 5N28W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION FROM 2N-11N BETWEEN 15N-30W. THE ITCZ IS DISRUPTED BY THE PRESENCE OF A TROPICAL WAVE AND SURFACE TROUGH DISCUSSED ABOVE. ...DISCUSSION... THE GULF OF MEXICO... A COOL AND DRY AIRMASS IS IN PLACE ACROSS THE GULF THIS AFTERNOON...AS SURFACE OBS SHOW N TO NW FLOW 10-15 KT ACROSS THE DISCUSSION AREA. AS THIS AIRMASS MOVES OVER THE WARM WATERS OF THE GULF...SATELLITE VISIBLE IMAGERY SHOWS STRATOCUMULUS CLOUDS FORMING E OF A LINE FROM 30N85W TO 19N96W. CLEAR SKIES ARE TO THE OTHER SIDE OF THE LINE. STRONG SUBSIDENCE ALOFT COVERS THE GULF AS WELL...SUPPORTING THE FAIR WEATHER ENVIRONMENT ACROSS THE AREA. CONDITIONS ARE EXPECTED TO REMAIN CONSTANT OVER THE NEXT 24 HOURS. THE CARIBBEAN SEA... CLUSTERS OF HEAVY SHOWERS AND THUNDERSTORMS CONTINUE TO AFFECT THE NW AND SW BASINS W OF 73W...ASSOCIATED TO THE COLD FRONT MENTIONED IN THE ATLC DISCUSSION. THE SOUTHERN EXTENSION OF THE COLD FRONT MOVES ACROSS ERN CUBA...AND EXTENDS SW TO N CENTRAL JAMAICA. N-NW WINDS BEHIND THE FRONT IN COMBINATION WITH ESE TRADE WINDS AHEAD OF IT ARE GENERATING AN AREA OF BROAD CYCLONIC LOW LEVEL CIRCULATION OVER THE SW CARIBBEAN. A SURFACE TROUGH IS ANALYZED IN THIS REGION FROM 18N80W TO 10N80W. THE CONVECTION ASSOCIATED TO THIS TROUGH IS CONCENTRATED OVER THE SRN HALF OF THE AXIS COVERING S OF 14N W OF 73W. SHORT RANGE COMPUTER MODELS SUGGEST THE CONVECTION IN THIS REGION WILL LINGER OVER THE NEXT 24 HOURS. OTHERWISE...FAIR WEATHER CONDITIONS PREVAIL ELSEWHERE ACROSS THE AREA...AS A BROAD UPPER ANTICYCLONE DRAWS DRY AND SUBSIDENT AIR ALOFT SUPPRESSING DEEP CONVECTION ACROSS THE AREA. THE ATLANTIC OCEAN... A DEEP LAYER TROUGH/CUT OFF LOW SWINGS ACROSS THE N-ERN CONUS SUPPORTING A COLD FRONT MOVING ACROSS THE WRN ATLC ANALYZED ALONG 32N70W TO ACROSS THE CENTRAL BAHAMAS NEAR 24N76W TO INTO THE CARIBBEAN ACROSS ERN CUBA ALONG 21N77W. SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN 60 NM ON EITHER SIDE OF THE BOUNDARY. THE FRONT AND ASSOCIATED CONVECTION IS EXPECTED TO CONTINUE TO PROGRESS ENE DURING THE NEXT 24 HOURS. AN UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED 23N50W. THIS CIRCULATION IS MOVING W-SW WITH WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 17N-30N BETWEEN 47W-57W. EXCEPT FOR THE CONVECTION ASSOCIATED TO A TROPICAL WAVE...FAIR WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE AREA PROVIDED BY A BROAD UPPER ANTICYCLONE COVERING THE WRN ATLC AHEAD OF THE FRONTAL CONVECTION...AND A BROAD SURFACE RIDGE OF HIGH PRESSURE ANCHORED N OF THE DISCUSSION AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA