000 AXNT20 KNHC 162337 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN OCT 16 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 2315 UTC. ...SPECIAL FEATURES... A BROAD AREA OF LOW PRESSURE COVERS THE NW CARIBBEAN...SE GULF OF MEXICO...AND YUCATAN PENINSULA FOCUSED ON A 1004 MB SURFACE LOW CENTERED NEAR 20N87W. THIS AREA OF LOW PRESSURE LIES BENEATH AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER WESTERN CUBA WHICH IS PROVIDING A LARGE AREA OF DIFFLUENCE ALOFT TO SUPPORT AND SUSTAIN NUMEROUS SHOWERS AND SCATTERED TSTMS FROM 19N-25N BETWEEN 78W-90W. FURTHER ORGANIZATION AND DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS THE LOW DRIFTS NW. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL IS EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS ACROSS THE YUCATAN PENINSULA...NW CARIBBEAN SEA...SE GULF OF MEXICO... INCLUDING THE FLORIDA STRAITS...AND INLAND PORTIONS OF WESTERN AND CENTRAL CUBA AND THE SOUTHERN FLORIDA PENINSULA. IN ADDITION...NORTHEAST TO EAST GALE FORCE WINDS ARE EXPECTED TO CONTINUE OVER THE SE GULF OF MEXICO WATERS FROM 21N-26N BETWEEN 81W-89W THROUGH MONDAY MORNING. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 10N19W TO 18N16W MOVING W AT 10-15 KT. CYCLONIC FLOW IS NOTED IN THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE WAVE AXIS AND ALSO IN SURFACE OBSERVATIONS LOCATED ALONG THE COAST OF W AFRICA. THE ONLY SIGNIFICANT CONVECTION AT THIS TIME IS SCATTERED MODERATE AND ISOLATED STRONG CONVECTION ALONG THE COAST OF W AFRICA FROM 07N-13N BETWEEN 12W-15W. TROPICAL WAVE IS ANALYZED FROM 07N39W TO 15N38W MOVING W AT 15-20 KT. SATELLITE IMAGERY INDICATES LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS WHICH WAS ALSO CONFIRMED BY AN EARLIER ASCAT PASS AROUND 16/1144 UTC. EMBEDDED WITHIN THE ITCZ...SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N-13N BETWEEN 35W-39W. TROPICAL WAVE IS ANALYZED FROM 10N59W TO 16N59W MOVING W AT 10-15 KT. WEAK CYCLONIC FLOW IS NOTED IN THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE WAVE AXIS BETWEEN 57W-61W. THE WAVE IS ALSO EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY OVER THE SE CARIBBEAN SEA AND PORTIONS OF THE TROPICAL NORTH ATLC. SCATTERED MODERATE CONVECTION IS FROM 11N-14N BETWEEN 57W-61W. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N26W TO 10N38W THEN FROM 08N41W TO 04N47W. ISOLATED MODERATE CONVECTION IS FROM 03N-09N BETWEEN 14W-25W...AND FROM 09N-13N BETWEEN 21W-28W. SCATTERED MODERATE CONVECTION IS FROM 03N-09N BETWEEN 40W-47W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES MOSTLY WESTERLY ZONAL FLOW IS LOCATED ACROSS THE EASTERN CONUS WITH AN UPPER LEVEL SHORTWAVE TROUGH PROGRESSING ACROSS THE CANADIAN MARITIMES. FARTHER SOUTH INTO THE GULF REGION...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 21N80W. WHILE THE UPPER LEVEL SHORTWAVE IS WELL NORTH OF THE AREA...A STATIONARY FRONT EXTENDS ACROSS THE SW NORTH ATLC...SOUTHERN FLORIDA PENINSULA...AND INTO THE SE GULF ALONG 26N81W TO 25N86W. AT THE WESTERN EXTENT OF THE FRONT...THE SPECIAL FEATURES LOW PRESSURE AREA CARRIES INFLUENCE OVER MUCH OF THE SOUTHEASTERN GULF...FLORIDA STRAITS AND SOUTHERN FLORIDA PENINSULA THIS EVENING. WITH THE FRONT...LOW...AND UPPER LEVEL DIFFLUENCE IN PLACE...NUMEROUS SHOWERS AND SCATTERED TSTMS ARE OCCURRING FROM 19N-25N BETWEEN 78W-90W. ELSEWHERE...SURFACE HIGH PRESSURE IS LOCATED ACROSS THE NORTHERN GULF AND WESTERN GULF W OF 93W...ANCHORED BY A 1020 MB HIGH CENTERED OVER SOUTHERN ALABAMA NEAR 32N87W. WATER VAPOR IMAGERY INDICATES DRY AIR AND RELATIVELY STRONG SUBSIDENCE NW OF A LINE FROM 22N98W TO 29N83W AND THE LAST FEW VISIBLE SATELLITE IMAGES OF THE DAY INDICATE CLEAR SKIES AND MOSTLY FAIR WEATHER. THE SPECIAL FEATURES LOW IS FORECAST TO DRIFT NORTHWESTWARD OVER THE NEXT COUPLE OF DAYS BEFORE LIFTING NORTHWARD DUE TO A COLD FRONT EXPECTED TO ENTER THE NW GULF WATERS TUESDAY. CARIBBEAN SEA... SIGNIFICANT LOW-LEVEL MOISTURE IS EVIDENT ON TOTAL PRECIPITABLE WATER IMAGERY W OF 80W ACROSS MUCH OF THE NW CARIBBEAN...WESTERN CUBA...THE YUCATAN PENINSULA...AND PORTIONS OF NORTHERN CENTRAL AMERICA FOCUSED ON A 1004 MB LOW CENTERED NEAR 20N87W. NUMEROUS SHOWERS AND SCATTERED TSTMS ARE OCCURRING FROM 19N-25N BETWEEN 78W-90W...INCLUDING THE YUCATAN CHANNEL AND WESTERN CUBA THIS EVENING. LOW-LEVEL MOISTURE EXTENDS SE OF THE LOW TO NORTHERN COLOMBIA AND PANAMA WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING OVER THE SW CARIBBEAN FROM 07N-16N BETWEEN 79W-86W. THE REMAINDER OF THE CARIBBEAN REMAINS UNDER THE INFLUENCE OF DRY NORTHEASTERLY UPPER LEVEL WINDS AS INDICATED BY WATER VAPOR IMAGERY...HOWEVER...ISOLATED LOW-TOPPED SHOWERS ARE NOTED E OF 79W. LASTLY...A TROPICAL WAVE ALONG 59W E OF THE LESSER ANTILLES IS FORECAST TO MOVE WESTWARD AND INCREASE MOISTURE AND INSTABILITY OVER THE ISLANDS THROUGH THE OVERNIGHT PERIOD INTO MONDAY. WHILE SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING BETWEEN BARBADOS AND TRINIDAD AT THIS TIME...THIS AREA OF PRECIPITATION IS EXPECTED TO IMPACT THE WINDWARD ISLANDS AS THE WAVE PASSES TO THE WEST. ATLANTIC OCEAN... AN UPPER LEVEL SHORTWAVE TROUGH LOCATED WELL NORTH OF THE DISCUSSION AREA OVER THE CANADIAN MARITIMES SUPPORTS A STATIONARY FRONT THAT EXTENDS FROM 35N61W TO 30N66W TO 25N75W TO THE SOUTHERN FLORIDA PENINSULA NEAR 26N81W. SCATTERED TO NUMEROUS SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 210 NM EITHER SIDE OF A LINE FROM 32N65W TO 24N81W. MOST OF THIS CONVECTION IS SUPPORTED ALOFT BY AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 22N80W WHICH EXTENDS AN UPPER LEVEL RIDGE AXIS NE TO BEYOND 32N56W. FARTHER EAST...AN UPPER LEVEL LOW CENTERED NEAR 32N33W SUPPORTS A 1017 MB LOW EMBEDDED WITHIN THE SUBTROPICAL SURFACE RIDGE NEAR 33N32W. A SURFACE TROUGH EXTENDS S-SW FROM THE LOW TO 26N38W. SCATTERED SHOWERS ARE OCCURRING MAINLY NORTH OF THE LOW CENTER FROM 32N-37N BETWEEN 27W-34W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN