000 AXNT20 KNHC 040555 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI OCT 04 2013 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... TROPICAL STORM KAREN IS CENTERED NEAR 24.5N 89.5W AT 04/0600 UTC OR ABOUT 280 NM S OF THE MOUTH OF THE MISSISSIPPI RIVER MOVING NNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SCATTERED MODERATE CONVECTION IS FROM 23N-27N BETWEEN 84W-89W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 11N47W TO 17N46W MOVING W AT 15 KT. THE WAVE REMAINS EMBEDDED WITHIN WEAK SURFACE TO 700 MB TROUGHING WITH A 700 MB RELATIVE VORTICITY MAXIMUM NOTED ALONG THE WAVE AXIS NEAR 15N. WIDELY SCATTERED MODERATE CONVECTION IS FROM 12N-17N BETWEEN 43W-48W. TROPICAL WAVE EXTENDS FROM 11N55W TO 19N54W MOVING W-NW AT 10 KT. THE WAVE CONTINUES TO SLOW IN SPEED AND STRETCH NORTHWARD AS THE SURFACE TO 700 MB TROUGHING BROADENS BETWEEN 50W-60W. WITH SOUTHWESTERLY WIND SHEAR ALOFT TO THE NW OF THE WAVE AXIS... CONVECTION REMAINS LIMITED AT THIS TIME WITH ONLY ISOLATED MODERATE CONVECTION OCCURRING FROM 10N-14N BETWEEN 51W-55W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO 07N27W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N27W TO 06N36W TO 09N54W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ACROSS THE EASTERN TROPICAL ATLC... SCATTERED MODERATE CONVECTION IS FROM 06N-15N BETWEEN 13W-18W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY CONCERN FOR THE GULF THIS EVENING IS TROPICAL STORM KAREN WHICH IS FORECAST TO TRACK NNW TOWARD THE MOUTH OF THE MISSISSIPPI RIVER BY LATE SATURDAY. KAREN REMAINS ON THE NORTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE NW CARIBBEAN SEA NEAR 20N86W. WITH A FAVORABLE UPPER LEVEL DIFFLUENT ENVIRONMENT IN THE VICINITY OF THE CYCLONE AND AREAS TO THE EAST...PLENTY OF MIDDLE TO UPPER LEVEL MOISTURE IS NOTED ON SATELLITE IMAGERY E OF 92W. ASIDE FROM KAREN'S CORE CONVECTION OF SCATTERED SHOWERS AND TSTMS FROM 23N-27N BETWEEN 84W-89W...ISOLATED SHOWERS AND TSTMS ARE OCCURRING ELSEWHERE FROM 21N-31N BETWEEN 83W-91W. ACROSS THE WESTERN GULF W OF 92W...MOSTLY CLEAR SKIES AND FAIR CONDITIONS PERSIST DUE TO A RELATIVELY DRY AND STABLE ENVIRONMENT ALOFT FOCUSED IN THE VICINITY OF A WEAK UPPER LEVEL LOW CENTERED NEAR 24N96W. LOOKING AHEAD...AS KAREN IS EXPECTED TO MAKE LANDFALL DURING THE UPCOMING WEEKEND...A COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA COAST LATE SATURDAY INTO SUNDAY USHERING IN NORTHERLY WINDS IN THE RANGE OF 15 TO 25 KT AND SURFACE RIDGING EXPECTED TO BUILD IN ACROSS THE WESTERN GULF THROUGH EARLY NEXT WEEK. CARIBBEAN SEA... MUCH OF THE WESTERN CARIBBEAN W OF 72W IS UNDER THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 20N86W PROVIDING THIS AREA WITH NORTHEASTERLY TO EASTERLY FLOW ALOFT. WATER VAPOR IMAGERY INDICATES THE AIRMASS REMAINS RELATIVELY DRY...HOWEVER MIDDLE TO UPPER LEVEL CLOUDINESS...PARTIAL OUTFLOW MOISTURE FROM TROPICAL STORM KAREN CENTERED IN THE GULF OF MEXICO...FANS OVER THE AREA N OF 15N W OF 78W. A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN THIS AREA PRIMARILY OFF THE SOUTHERN COAST OF CUBA AND IN THE VICINITY OF THE CAYMAN ISLANDS FROM 18N-22N BETWEEN 78W-82W. TO THE SOUTH ACROSS THE SW CARIBBEAN... SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING S OF 12N... INCLUDING INLAND PORTIONS OF NORTHERN COLOMBIA...PANAMA...AND COSTA RICA. THIS PARTICULAR CONVECTION IS LIKELY DUE TO LOW- LEVEL MOISTURE CONVERGENCE AND THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ANALYZED ALONG 10N. E OF 72W...UPPER LEVEL FLOW REMAINS ANTICYCLONIC...HOWEVER IS MOIST SOUTH-SOUTHWESTERLY FLOW ALOFT. WATER VAPOR IMAGERY ALSO SHOWS THIS AIRMASS TO BE RELATIVELY DRY ALOFT WITH ONLY A FEW PASSING MIDDLE TO UPPER LEVEL CLOUDS E OF 68W. AT THE SURFACE...E-SE TRADES PERSIST WITH ISOLATED LOW-TOPPED SHOWERS EMBEDDED WITHIN E OF 70W. HISPANIOLA... CURRENTLY HISPANIOLA IS BENEATH THE BASE OF AN UPPER LEVEL LOW CENTERED OVER THE SW NORTH ATLC NEAR 25N67W. SATELLITE IMAGERY INDICATES LOW-LEVEL MOISTURE INCREASES TO THE NORTH OF 20N WITH ENHANCEMENT OF ISOLATED SHOWERS DUE TO THE MARGINAL UPPER LEVEL DYNAMICS ASSOCIATED WITH THE UPPER LEVEL LOW. A FEW ISOLATED SHOWERS CONTINUE TO LINGER ACROSS THE ISLAND THIS EVENING WITH E- SE TRADES CONTINUING TO USHER IN LOW-LEVEL MOISTURE AND A HIGHER PROBABILITY OF A PASSING ISOLATED SHOWER DURING THE OVERNIGHT PERIOD. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL RIDGE ANCHORED OVER THE NW CARIBBEAN SEA CONTINUES TO PROVIDE DRY NORTHERLY FLOW ALOFT W OF 70W FOR PORTIONS OF THE SW NORTH ATLC THIS EVENING. WHILE ONLY A FEW UPPER LEVEL CLOUDS ARE NOTED OVER THIS AREA...AT THE SURFACE... RIDGING DOMINATES ANCHORED BY A 1022 MB HIGH CENTERED OFF THE CAROLINA COAST NEAR 34N71W. TO THE EAST OF 70W OVER THE REMAINDER OF THE SW NORTH ATLC...WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL LOW CENTERED NEAR 25N71W THAT IS PROVIDING AMPLE LIFT OF LOW-LEVEL MOISTURE TO INCREASE CLOUDINESS AND GENERATE ISOLATED SHOWERS FROM 18N-29N BETWEEN 62W-72W. ACROSS THE CENTRAL ATLC...AN UPPER LEVEL TROUGH AXIS DIPS INTO THE DISCUSSION AREA NEAR 32N49W SW TO 28N55W THAT SUPPORTS A COLD FRONT ANALYZED FROM 35N47W TO 31N52W AND A PRE-FRONTAL SURFACE TROUGH FROM 28N52W TO 32N45W. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. TO THE EAST OF THESE FEATURES...AND QUICKLY BECOMING EMBEDDED WITHIN THE FRONTAL TROUGHING N OF 30N...THE REMNANT 1012 MB LOW OF JERRY IS CENTERED NEAR 32N38W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING PRIMARILY TO THE EAST OF THE LOW CENTER FROM 31N-34N BETWEEN 32W-38W. THE FRONTAL TROUGHING STRETCHES SOUTH-SOUTHWEST OF THE REMNANT LOW REMAINING BROAD...BUT LOCATED IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM 21N42W TO 26N41W. WIDELY SCATTERED SHOWERS AND TSTMS ARE OCCURRING EAST OF THE AXIS FROM 21N-28N BETWEEN 36W-41W. OTHERWISE THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A PAIR OF 1020 MB HIGHS CENTERED NEAR 26N29W AND 34N29W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN