000 AXNT20 KNHC 181741 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE OCT 18 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 CAPE VERDE ISLANDS NEAR 17N24W TO 11N34W W AT 10-15 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. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE MOSTLY OVER THE NRN HALF OF THE WAVE AXIS FROM 13N-20N BETWEEN 20W-30W. TROPICAL WAVE IS ANALYZED IN THE CENTRAL TROPICAL ATLC FROM 12N45W TO 5N50W MOVING W 10-15 KT. WAVE IS WELL DEFINED AND IS AT THE LEADING EDGE OF A MOISTURE SURGE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE FROM 7N-12N BETWEEN 43W-50W. TROPICAL WAVE IS ANALYZED OVER THE CENTRAL CARIBBEAN FROM 17N68W TO 10N70W MOVING 10-15 KT. WAVE IS BEING SUPPRESSED BY A DRY AND SUBSIDENT AIRMASS ALOFT INTRUDING ACROSS THE ERN AND N CENTRAL BASIN ON WATER VAPOR IMAGERY. WEAK CYCLONIC TURNING IS OBSERVED ON THE LOW LEVEL CLOUD FIELD ALONG THE SRN EXTENSION OF THE WAVE AXIS. NO SIGNIFICANT CONVECTION IS AROUND THIS SYSTEM. ...THE ITCZ/THE MONSOON TROUGH... DUE TO THE LARGE CYCLONIC WIND FIELD ASSOCIATED TO THE TROPICAL WAVES...THE OCEANIC MONSOON TROUGH IS DISRUPTED AND THE OTHER PORTION OF IT REMAINS INLAND OVER NRN AFRICA. CONSEQUENTLY...THE ITCZ IS DISRUPTED BY THE PRESENCE OF THESE TROPICAL WAVES. NEVERTHELESS... AN AREA OF SCATTERED WEAK CONVECTION IS FROM 4N-10N BETWEEN 15W-22W. ...DISCUSSION... GULF OF MEXICO... THE MAIN AREA OF ACTIVE WEATHER CONTINUES TO FOCUS AROUND THE SET OF SURFACE LOWS IMPACTING THE SE GULF. THE MAIN CIRCULATION IS ANALYZED AS A 1003 MB LOW NEAR 26N88W. THE WEAKER/DISSIPATING CIRCULATION HAS STAYED WOBBLING OVER THE NORTHERN COASTAL WATERS OF THE YUCATAN PENINSULA NEAR 22N88W. A SURFACE TROUGH CROSSES THE MAIN LOW FROM 30N85W TO THE LOW CENTER...THEN S TO NEAR 24N88W. THE CIRCULATION AROUND THIS SYSTEM COVERS A GREAT PORTION OF THE BASIN E OF 93W...RAGING FROM 15 KT TO NEAR GALE FORCE CRITERIA S OF 28N E OF 91W. DESPITE THE LOCATION OF THESE SURFACE FEATURES ...AN UPPER LEVEL SHORTWAVE/TROUGH IS DRIVING THE CONVECTION TO THE EAST OF THE LOWS E OF 87W. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE IN THIS REGION...WITH THE POSSIBILITY OF STRONG GUSTY OUT FLOW BOUNDARIES AND WATER SPOUTS. AS THE SYSTEM CONTINUES TO TRACK NE...LOCALLY HEAVY RAINFALL...GUSTY WINDS... AND POSSIBLE SEVERE WEATHER OVER THE FLORIDA KEYS...THE FLORIDA PENINSULA...SOUTHERN GEORGIA...AND COASTAL SECTIONS OF THE CAROLINAS ARE EXPECTED OVER THE NEXT DAY OR SO. FOR INFORMATION SPECIFIC TO YOUR AREA PLEASE SEE STATEMENTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. ANOTHER AREA OF SIGNIFICANT WEATHER IS OCCURRING OVER THE NW GULF AS A COLD FRONT MOVES OFF THE TEXAS COAST RAPIDLY WITH NEAR GALE FORCE WINDS IN ITS WAKE...AS OBSERVED FROM BUOYS AND NOAA SHIPS. CURRENTLY THE FRONT EXTENDS FROM THE COAST OF LOUISIANA TO THE MEXICO COAST ALONG 29N91W TO 24N98W. A LINE OF HEAVY SHOWERS AND THUNDERSTORMS DEFINE THE FRONTAL BOUNDARY ON VISIBLE SATELLITE IMAGERY. SHORT RANGE COMPUTER MODELS SUGGEST THIS FRONT WILL CONTINUE TO MOVE QUICKLY ACROSS THE AREA. IN THE MEAN TIME ...A SECOND PUSH OF DRYER AND COOLER AIRMASS WILL ENTER THE NW BASIN WITH GALE WINDS EXPECTED TO DEVELOP OVER THE FAR SW BASIN AND BAY OF CAMPECHE. HIGH PRESSURE WILL BUILD OVER THE ENTIRE AREA GULF IN THE WAKE OF THE FRONT THROUGH SATURDAY. CARIBBEAN SEA... THE BROAD AREA OF LOW PRESSURE OVER THE GULF OF MEXICO COVERS THE FAR NW CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 19N W OF 83W. OTHERWISE...MOST OF THE CARIBBEAN BASIN IS EXPERIENCING FAIR WEATHER CONDITIONS THIS AFTERNOON...EXCEPT FOR THE FAR SW BASIN. THE BENIGN WEATHER IS OBSERVED AS A DRY AND SUBSIDENT AIRMASS ALOFT INTRUDES ACROSS THE ERN AND N CENTRAL BASIN SUPPRESSING DEEP CONVECTION. WHILE THE CONVECTION OVER THE FAR NW BASIN IS RELATED TO THE SYSTEM OVER THE GULF OF MEXICO...THE CONVECTION OVER THE SW BASIN IS RELATED TO MONSOONAL FLOW ACROSS THIS AREA GENERATING SCATTERED HEAVY SHOWERS AND ISOLATED THUNDERSTORMS S OF 15N W OF 75W. A TROPICAL WAVE MOVES ACROSS THE CENTRAL BASIN WITHOUT ANY SIGNIFICANT CONVECTION...SEE ABOVE FOR MORE DETAILS. OTHERWISE ...LIGHT EASTERLY TRADE FLOW PREDOMINATES ACROSS THE AREA... BECOMING SSE W OF 75W IN RESPONSE OF THE LOWER PRESSURES RELATED TO THE GULF OF MEXICO SYSTEM. THE COLD FRONT CURRENTLY MOVING ACROSS THE GULF WILL MOVE INTO THE NW CARIBBEAN TONIGHT THEN BE ABSORBED BY A STRONGER COLD FRONT THAT PUSHES INTO THE NW CARIBBEAN BY WED EVENING. THE TROPICAL WAVE WILL WEAKEN OVER THE CENTRAL CARIBBEAN LATE WED NIGHT. ATLANTIC OCEAN... SSE 10-20 KT SURFACE FLOW COVERS THE WRN BASIN DRAWING LOW LEVEL MOISTURE NOTICED ON TOTAL PRECIPITABLE WATER PRODUCT. THESE LOW LEVEL CONDITIONS ALONG WITH A DIFFLUENT ENVIRONMENT ALOFT IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS W OF 73W. AN ELONGATED UPPER LEVEL CIRCULATION CENTERED NEAR 20N50W AND AN UPPER LEVEL RIDGE CENTERED OVER ERN CUBA IS DRAWING A DRY AIRMASS INTO THE ERN AND N CENTRAL CARIBBEAN. TO THE E OF THIS CIRCULATION...AN UPPER LEVEL CYCLONIC CIRCULATION IS NEAR 30N30W AND ITS SURFACE REFLECTION IS CENTERED AROUND A WEAK 1016 MB LOW NEAR 30N37W. THE CONVECTION ASSOCIATED TO THIS SYSTEM IS WELL REMOVED TO THE E OF THE SURFACE LOW...N OF 27N BETWEEN 23W-32W. THE BROAD LOW PRESSURE OVER THE GULF OF MEXICO WILL TRACK NE AHEAD OF A STRONG COLD FRONT THAT WILL MOVE OFF THE NE FLORIDA COAST WED EVENING WITH CONVECTION. BY THURSDAY THE FRONT WILL WEAKEN AND BECOME STATIONARY. WEAK HIGH PRESSURE WILL BUILD ACROSS THE AREA BEHIND THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA