000 AXPZ20 KNHC 020311 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU OCT 02 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...SPECIAL FEATURES... TROPICAL STORM MARIE IS CENTERED NEAR 18.0N 119.5W...ABOUT 600 NM SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 01/0300 UTC MOVING WNW OR 285 DEG AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH HIGHER GUSTS. CONVECTION ASSOCIATED WITH MARINE HAS DECREASED AND BECOME RAGGED THIS EVENING LIKELY DUE TO THE INGEST OF DRY STABLE AIR. HOWEVER...GIVEN THAT THE SHEAR IS LIGHT AND SSTS ARE MARGINALLY WARM...MODEST STRENGTHENING IS FORECAST FOR THE NEXT 12-24 HOURS. BEYOND THAT...MARIE WILL TRACK OVER COOLER WATERS CAUSING A LOSS OF DEEP CONVECTION AND STEADY WEAKENING. SEE THE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AN THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. A 1009 MB LOW PRESSURE SYSTEM IS DRIFTING WNW CENTERED ABOUT 300 NM SSW OF THE GULF OF TEHUANTEPEC NEAR 13N99W. THIS FEATURE HAS BECOME A LITTLE BETTER ORGANIZED THROUGHOUT THE DAY AS CONVECTION HAS GENERALLY INCREASED OVER THE WRN SEMICIRCLE WITH A FAIRLY PERSISTENT AREA JUST W OF THE PARTIALLY EXPOSED LOW-LEVEL CENTER. MICROWAVE DATA CONFIRMS WHAT IS SEEN ON SATELLITE IMAGERY AND ALSO REVEALS A FAIRLY WELL DEFINED CIRCULATION. DUE TO THIS IMPROVED STRUCTURE AND OVERALL FAIR ATMOSPHERIC ENVIRONMENT...THIS SYSTEM HAS A HIGH POTENTIAL FOR TROPICAL CYCLONE FORMATION WITH THE NEXT 48 HOURS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N85W 13N98W 11N115W 09N124W 10N140W. SCATTERED MODERATE TO STRONG CONVECTION IS N OF 06N BETWEEN 84W-89W AND FROM 10N-17N BETWEEN 98W-112W. ...DISCUSSION... E OF 115W... AN UPPER DIFFLUENT PATTERN ASSOCIATED WITH A HIGH CENTERED WSW OF THE SRN TIP OF BAJA AND A TROUGH OVER THE GULF OF MEXICO (AND ITS ASSOCIATED JET) IS AIDING IN THE PRODUCTION OF MOISTURE OVER THE TROPICS. MUCH OF THE ASSOCIATED DEEP CONVECTION IS ALREADY COVERED ABOVE IN THE ITCZ AND SPECIAL FEATURES SECTION. GAP WINDS...NO HELP FROM SCATTEROMETER DATA SO FAR THIS EVENING BUT SHIP SFRZ IS REPORTING 23 KT E WINDS NEAR 15N97W. USING THIS DATA...SYNOPTIC PATTERN AND GFS/NAM GUIDANCE...NE TO E WINDS 20-25 KT ARE EXPECTED IN THE GULF OF TEHUANTEPEC TONIGHT. THESE WINDS WILL LIKELY WEAKEN A TAD BUT ARE EXPECTED TO PERSIST FOR A COUPLE MORE DAYS. W OF 115W... TROPICAL STORM MARIE IS THE MAIN CONCERN AS IT IS EXPECTED TO GENERALLY TRACK WWD WITH SOME STRENGTHENING POSSIBLE BEFORE IT ENCOUNTERS COOLER WATERS. REFER TO THE SPECIAL FEATURE SECTION FOR MORE DETAILS. AN UPPER TROUGH OFF THE WEST COAST OF THE U.S. HAS BECOME ELONGATED AND IS PULLING NE NOW PROVIDING LIMITED SUPPORT FOR A DISSIPATING STATIONARY FRONT FROM 30N131W TO 21N140W. EARLIER ASCAT DATA STILL SUGGESTED SOME S TO SW WINDS TO 20 KT NEAR THE FRONT...BUT TOOK MENTION OF WINDS OUT OF THE LATEST HIGH SEAS GIVEN THE STEADY WEAKENING OF THE BOUNDARY. NONETHELESS...LARGE NW SWELLS...UP TO 13 FT...CONTINUE TO SPREAD SE OUTRUNNING THE STALLED BOUNDARY. THESE SWELLS ARE EXPECTED TO GRADUALLY DISSIPATE OVER THE NEXT FEW DAYS. A COUPLE OF WEAK 1011 MB SFC LOWS ARE ANALYZED NEAR 11N137W AND 11N144W. WHILE THESE FEATURES ARE PERTURBING THE ITCZ NWD...MUCH OF THE ASSOCIATED CONVECTION HAS DISSIPATED THIS EVENING. $$ CANGIALOSI