000 AXNT20 KNHC 232340 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED OCT 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... TROPICAL STORM LORENZO IS CENTERED NEAR 29.3N 48.7W AT 23/2100 UTC OR ABOUT 850 NM E OF BERMUDA MOVING E AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. ISOLATED MODERATE CONVECTION IS FROM 27N-28N BETWEEN 46W-49W. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. GALE FORCE WINDS ARE OCCURRING IN THE SW GULF OF MEXICO IN ASSOCIATION WITH A COLD FRONT ANALYZED FROM THE SOUTHERN FLORIDA PENINSULA SOUTHWEST TO THE EASTERN BAY OF CAMPECHE NEAR 21N91W. A RECENT ASCAT PASS AROUND 23/1536 UTC INDICATED NORTHERLY WINDS IN THE RANGE OF 30 TO 35 KT IN THE VICINITY OF 19N96W WITH SEAS BEGINNING A GRADUAL SUBSIDING TREND FROM A MAXIMUM OF 13 FT. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 06N27W TO 14N24W MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH BROAD LOW-LEVEL TROUGHING ACROSS THE EASTERN ATLC AND A RELATIVE MAXIMUM IN TOTAL PRECIPITABLE WATER AS NOTED ON IMAGERY FROM 04N-12N BETWEEN 19W-30W. WIDELY SCATTERED MODERATE CONVECTION SPANS MOSTLY THE SAME AREA FROM 03N-12N BETWEEN 20W-29W. TROPICAL WAVE EXTENDS FROM 09N55W TO 17N57W MOVING W AT 10-15 KT. WATER VAPOR IMAGERY INDICATES VERY DRY AIR AND STRONG SUBSIDENCE ON THE WESTERN PERIPHERY OF AN UPPER LEVEL LOW CENTERED NEAR 16N48W THAT IS INHIBITING ANY SIGNIFICANT DEEP CONVECTION WITH THE WAVE AT THIS TIME. LOW-LEVEL MOISTURE HOWEVER CONTINUES TO MOVE WEST WITH ISOLATED SHOWERS POSSIBLE WITHIN 180 NM EITHER SIDE OF THE AXIS. TROPICAL WAVE EXTENDS FROM 11N83W TO 17N83W MOVING W AT 10 KT. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE WAVE AXIS ALONG WITH AMPLE MIDDLE TO UPPER LEVEL DIFFLUENCE OVER CENTRAL AMERICA IS GENERATING SCATTERED MODERATE AND ISOLATED STRONG CONVECTION FROM 10N-16N BETWEEN 82W-87W...INCLUDING PORTIONS OF COSTA RICA...NICARAGUA...AND HONDURAS THIS EVENING. LOCALLY HEAVY RAINFALL THIS EVENING MAY LEAD TO LOCALIZED FLOODING AND MUDSLIDES ACROSS THESE AREAS. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO 10N25W THEN RESUMES NEAR 07N29W TO 07N37W TO 05N43W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 26W...ISOLATED MODERATE CONVECTION IS FROM 03N-09N BETWEEN 29W-36W...AND FROM 05N-11N BETWEEN 36W-49W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL LONGWAVE TROUGH IS ACROSS THE EASTERN CONUS PROVIDING SOUTHWESTERLY FLOW ALOFT FOR MUCH OF THE GULF THIS EVENING. THE TROUGHING SUPPORTS A PAIR OF COLD FRONTS ANALYZED ACROSS THE BASIN WHICH CONTINUE TO FILTER IN A COOLER AND DRIER AIRMASS IN THEIR WAKE. THE PRIMARY COLD FRONT EXTENDS FROM THE SW NORTH ATLC ACROSS THE SOUTHERN FLORIDA PENINSULA AND INTO THE SE GULF NEAR 26N82W THEN WSW TO 23N90W THEN SW TO THE MEXICO COAST NEAR 19N93W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT E OF 87W. W OF 87W... SCATTERED SHOWERS AND TSTMS ARE OCCURRING WITHIN 180 NM EITHER SIDE OF THE FRONT...INCLUDING CONVECTION ACROSS THE YUCATAN PENINSULA. A SECONDARY COLD FRONT IS ANALYZED FROM NEAR THE FLORIDA BIG BEND REGION NEAR 28N84W SW TO 22N97W. WHILE THE SECONDARY FRONT IS RELATIVELY DRIER THAN THE PRIMARY FRONT... ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT. THIS REINFORCING FRONT CONTINUES TO BECOME DIFFUSE AND IS EXPECTED TO DISSIPATE FULLY OVER THE NEXT 3 TO 6 HOURS. TO THE NORTHWEST OF THIS SECONDARY BOUNDARY...A 1022 MB HIGH IS CENTERED ACROSS SOUTHERN TEXAS NEAR 29N99W WITH THE RIDGING EXPECTED TO CONTINUE BUILDING IN ACROSS NORTHERN PORTIONS OF THE BASIN THROUGH LATE THURSDAY. CARIBBEAN SEA... AN UPPER LEVEL LOW IS CENTERED OVER THE WINDWARD PASSAGE NEAR 20N74W THAT IS PROVIDING A SMALL AREA OF DRY AIR ALOFT OVER THE NW CARIBBEAN THIS EVENING. SATELLITE IMAGERY INDICATES A SMALL AREA OF RELATIVELY CLEAR SKIES...HOWEVER SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS CUBA...JAMAICA...AND THE ADJACENT COASTAL WATERS. ALSO TO THE SOUTH...A TROPICAL WAVE IS ANALYZED ALONG 84W THAT IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 10N-16N BETWEEN 82W-87W...INCLUDING INLAND PORTIONS OF CENTRAL AMERICA. IN ADDITION...THE MONSOON TROUGH AXIS EXTENDS ALONG 10N BETWEEN NORTHERN COLOMBIA AND NORTHERN COSTA RICA ENHANCING CONVECTION S OF 12N. FARTHER EAST...SOUTH-SOUTHWESTERLY FLOW EAST OF THE UPPER LEVEL LOW AND ASSOCIATED TROUGH AXIS IS PROMOTING AN UPPER LEVEL DIFFLUENT ENVIRONMENT OVER THE CENTRAL AND EASTERN CARIBBEAN. ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 12N-19N BETWEEN 70W-78W IN ASSOCIATION WITH THE UPPER LEVEL LOW WITH ANOTHER AREA OF ISOLATED SHOWERS AND TSTMS OCCURRING ACROSS THE EASTERN CARIBBEAN IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM 13N67W TO 17N65W. AS THE UPPER LEVEL LOW GRADUALLY LIFTS NORTHWARD AND WEAKENS THROUGH LATE FRIDAY...CONTINUED ADVECTION OF MOISTURE E OF 75W WILL PROVIDING THE EASTERN CARIBBEAN WITH THE POTENTIAL FOR SHOWERS AND TSTMS UNTIL THE WEEKEND. HISPANIOLA... CURRENTLY SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW IS OVER HISPANIOLA DUE TO AN UPPER LEVEL LOW CENTERED OVER THE WINDWARD PASSAGE NEAR 20N74W. WITH MOISTURE AND LIFTING DYNAMICS IN PLACE ACROSS THE ISLAND THIS EVENING...CONTINUED ISOLATED SHOWERS ARE EXPECTED THROUGH THE OVERNIGHT HOURS INTO THURSDAY. ANOTHER AREA OF LOW-LEVEL MOISTURE ASSOCIATED WITH A SURFACE TROUGH ANALYZED ACROSS THE EASTERN CARIBBEAN WILL DRIFT CLOSER BY EARLY THURSDAY ADDING TO THE POTENTIAL FOR AFTERNOON AND EVENING CONVECTION AS THE UPPER LEVEL LOW LIFTS NORTHWARD AND DISSIPATES BY THE WEEKEND. ATLANTIC OCEAN... AN UPPER LEVEL LONGWAVE TROUGH IS OVER THE EASTERN CONUS THIS EVENING THAT SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N72W. THE COLD FRONT STRETCHES SW TO THE SOUTHERN FLORIDA PENINSULA NEAR 27N80W AND CONTINUES TO GENERATE WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 240 NM EAST OF THE FRONT AND WITHIN 90 NM WEST OF THE FRONT. FARTHER EAST...A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION DOMINATES THE REMAINDER OF THE CENTRAL AND EASTERN ATLC CENTERED NEAR 29N54W. ASIDE FROM TROPICAL STORM LORENZO EMBEDDED WITHIN THE MID-LEVEL RIDGING...AT THE SURFACE A RIDGE REMAINS ANCHORED BY A 1018 MB HIGH CENTERED NEAR 27N40W. THE RIDGE AXIS EXTENDS SW FROM THE HIGH TO NORTH OF HISPANIOLA NEAR 22N70W AND DUE EAST FROM THE HIGH TO THE CANARY ISLANDS NEAR 28N16W. FINALLY...THE EXTREME NORTHEASTERN FRINGE OF THE DISCUSSION AREA IS INFLUENCED BY A COLD FRONT ANALYZED FROM 32N30W TO 31N38W TO 32N44W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 180 NM SOUTH OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN