000 AXNT20 KNHC 161745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... A BROAD AREA OF LOW PRESSURE CONTINUES TO COVER THE NW CARIBBEAN...SE GULF OF MEXICO...AND SRN MEXICO CONCENTRATED AROUND A 1004 MB SURFACE LOW LOCATED ALONG THE MONSOON TROUGH OVER BELIZE NEAR 19N88W. THIS AREA OF LOW PRESSURE LIES UNDERNEATH AN AREA OF DIFFLUENCE ALOFT AROUND THE WRN SIDE OF AN UPPER RIDGE CENTERED OVER THE SE BAHAMAS. THIS PATTERN IS SUPPORTING NUMEROUS MODERATE/STRONG CONVECTION FROM 16N-19N BETWEEN 82W-84W...AND FROM 19N-23N BETWEEN 78W-89W INCLUDING WRN CUBA...BELIZE...AND THE NE YUCATAN PENINSULA. FURTHER DEVELOPMENT OF THIS SYSTEM IS POSSIBLE AS THE LOW DRIFTS NW. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL IS POSSIBLE OVER THE YUCATAN PENINSULA...NW CARIBBEAN...AND SE GULF. IN ADDITION...GUSTY WINDS UP TO GALE FORCE ARE ALREADY OCCURRING S OF 25N BETWEEN 85W-90W. ...TROPICAL WAVES... TROPICAL WAVE IN THE CENTRAL TRPCL ATLC EXTENDS FROM 15N38W THROUGH A 1009 MB LOW NEAR 11N39W TO 7N40W MOVING W 15-20 KT. SATELLITE IMAGERY INDICATES LOW LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS CONFIRMED BY AN ASCAT SCATTEROMETER PASS FROM AROUND 1144 UTC. THE WAVE ALSO LIES ON THE WRN SIDE OF A MAXIMUM IN DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. A CLUSTER OF NUMEROUS STRONG CONVECTION IS FROM 9N-12N BETWEEN 35W-38W...WITH SCATTERED MODERATE/STRONG CONVECTION ELSEWHERE FROM 6N-14N BETWEEN 32W-40W. TROPICAL WAVE IN THE WRN TRPCL ATLC IS ALONG 17N57W TO 10N60W MOVING W NEAR 15 KT. LOW LEVEL CYCLONIC FLOW IS EVIDENT IN BOTH SATELLITE IMAGERY AS WELL AS FROM A WINDSAT SCATTEROMETER PASS FROM 0956 UTC. THE WAVE IS ALSO EMBEDDED WITHIN A SURGE OF DEEP LAYER MOISTURE INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION 12N-14N BETWEEN 55W-60W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC ALONG 16N16W 9N20W 8N27W. THE ITCZ CONTINUES FROM 8N27W TO 9N36W...AND PICKS UP ON THE OTHER SIDE OF A TROPICAL WAVE ALONG 6N42W TO 7N54W. ISOLATED MODERATE/STRONG CONVECTION IS WITHIN 220 NM N OF THE AXIS...AND 300 NM S OF THE AXIS BETWEEN THE AFRICAN COAST AND 29W. NUMEROUS MODERATE/STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 41W-45W. ISOLATED MODERATE CONVECTION IS N OF THE AXIS FROM 9N-13N BETWEEN 50W-56W. ...DISCUSSION... GULF OF MEXICO... A BROAD LONGWAVE UPPER TROUGH IS MOVING OVER THE NW ATLC SUPPORTING A STATIONARY FRONT THAT EXTENDS ACROSS S FLORIDA ALONG 26N TO 86W. MOIST SWLY FLOW ALOFT IS DRAWING MOISTURE ACROSS THE SE GULF SUPPORTING OVERCAST SKIES AND SCATTERED SHOWERS S OF 27N E OF 90W. MOST OF THE MOISTURE IN THIS AREA IS ASSOCIATED WITH AN AREA OF LOW PRESSURE TO THE S OVER THE NW CARIBBEAN AND YUCATAN PENINSULA WHICH IS SUPPORTING NUMEROUS SHOWERS S OF 24N. A FEW SCATTERED SHOWERS ARE ALSO POPPING UP OVER THE SW GULF IN THE BAY OF CAMPECHE. GALE FORCE WINDS ARE NOTED S OF 25S BETWEEN 85W-90W. SEE SPECIAL FEATURES FOR MORE DETAILS ON THIS DISTURBANCE. HIGH SURFACE PRESSURE IS BUILDING INTO THE NRN GULF AROUND A 1018 MB HIGH OVER SRN TEXAS AND A 1022 MB HIGH OVER GEORGIA. WATER VAPOR IMAGERY INDICATES DRY AIR AND SUBSIDENCE ACROSS THE NRN AND NW GULF PROVIDING MOSTLY FAIR WEATHER. EXPECT MOIST CONDITIONS TO REMAIN ACROSS THE SE GULF OVER THE NEXT SEVERAL DAYS AS THE LOW PRESSURE SYSTEM IN THE NW CARIBBEAN DRIFTS NW. CARIBBEAN SEA... SIGNIFICANT MOISTURE LIES ACROSS THE NW CARIBBEAN ASSOCIATED WITH BROAD LOW PRESSURE CENTERED AROUND A 1004 MB LOW NEAR 19N88W. THIS LOW IS ALONG THE MONSOON TROUGH THAT EXTENDS ACROSS SRN MEXICO TO THE SRN YUCATAN AND INTO THE NW CARIBBEAN ALONG 20N TO 80W. THIS SYSTEM IS CURRENTLY PRODUCING SIGNIFICANT RAINFALL OVER WRN CUBA AND THE NRN YUCATAN. THE HIGH MOISTURE VALUES EXTEND SWD INTO THE SW CARIBBEAN WHERE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 14N BETWEEN 77W-84W. ALOFT...AN UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE BASIN. WHILE THE WRN CARIBBEAN IS WET...THE UPPER RIDGE IS ADVECTING DRY AIR INTO THE ERN AND CENTRAL CARIBBEAN FROM THE CENTRAL ATLC PROVIDING MOSTLY FAIR CONDITIONS. A TROPICAL WAVE E OF THE LESSER ANTILLES WILL BEGIN TO BRING SHOWERS TO THE ISLANDS SOON AS THE WAVE CONTINUES TO MOVE WWD. EXPECT VERY MOIST CONDITIONS TO REMAIN OVER THE NW CARIBBEAN ESPECIALLY THE YUCATAN PENINSULA AND WRN CUBA. ATLANTIC OCEAN... A BROAD UPPER TROUGH OVER THE NW ATLC SUPPORTS A STATIONARY FRONT THAT EXTENDS ALONG 32N64W 27N72W ACROSS THE NW BAHAMAS TO FLORIDA NEAR 26N80W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE FRONT. AN UPPER LEVEL RIDGE IS CENTERED NEAR 22N73W DRAWING MOISTURE FROM THE NW CARIBBEAN DISTURBANCE TOWARDS THE NE SUPPORTING UPPER LEVEL CLOUDS. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1031 MB HIGH NEAR 44N29W WHICH DOMINATES MUCH OF THE CENTRAL AND ERN ATLC. A SECOND UPPER RIDGE COVERS THE TROPICAL ATLC CENTERED NEAR 12N26W. EXPECT THE STATIONARY FRONT TO GRADUALLY DISSIPATE WHILE SURFACE RIDGING BUILDS INTO THE WRN ATLC. A WEAK SURFACE LOW N OF THE DISCUSSION AREA IN THE CENTRAL ATLC WILL ALSO DIP SOUTH INTO THE AREA. 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