000 AXPZ20 KNHC 020932 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU OCT 02 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... TROPICAL STORM MARIE IS CENTERED NEAR 18.0N 120.0W...ABOUT 630 NM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 01/0900 UTC MOVING WNW OR 280 DEG AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. MARIE HAD BEEN SHOWING SIGNS OF WEAKENING YESTERDAY AS DRY AIR WRAPPED INTO THE STORMS WEST SIDE...AND AS THE STORM MOVED INTO SLIGHTLY COOLER WATER. ALTHOUGH OVERALL CONVECTION AROUND MARIE HAS DECREASED OVER THE PAST 12 HOURS...A SMALL AREA OF CONVECTION HAS ERUPTED ON THE WEST SIDE OF THE CENTER OF MARIE IN THE PAST 3 HOURS. GIVEN THAT THE EASTERLY SHEAR REMAINS LIGHT TO MODERATE AND SSTS ARE STILL 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 CENTERED NEAR 13N99W APPROXIMATELY 260 NM S OF ACAPULCO MEXICO...MOVING SLOWLY WEST. THIS LOW REMAINS EMBEDDED IN AN ELONGATED TROUGH TO THE NORTHEAST. SHORT WAVE IR IMAGERY HINTS OF MULTIPLE CENTERS ALONG THE TROUGH. CONVECTION HAS WEAKENED CONSIDERABLY OVER THE PAST FEW HOURS...AND THE SYSTEM HAS LOST SOME OF ITS EARLIER ORGANIZATION. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR DEVELOPMENT AND THIS SYSTEM MAY INTENSIFY TO A TROPICAL DEPRESSION LATER TODAY. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N86W 13N92W 13N111W 08N124W 10N140W. SCATTERED MODERATE CONVECTION FROM 05N TO 08N BETWEEN 83W AND 88W. SCATTERED MODERATE TO STRONG CONVECTION BETWEEN THE ITCZ AXIS AND THE CENTRAL AMERICAN COAST BETWEEN COSTA RICA AND GUATEMALA. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM N OF AXIS BETWEEN 97W AND 99W. ...DISCUSSION... E OF 110W... AN ASCAT PASS AROUND 03Z INDICATED PERSISTENT 20 TO 25 KT NORTHERLY WINDS THOUGH THE GULF OF TEHUANTEPEC...CURVING WESTWARD AND CONVERGING INTO THE NORTHERN SIDE OF THE LOW NEAR 13N99W. SCATTEROMETER DATA OVER THE PAST 6 HOURS ALSO SHOW CONTINUED 15 TO 20 KT S TO SW FLOW S OF THE ITCZ. ALOFT...A DEEP LAYER TROUGH IS SHIFTING E THROUGH 94W N OF 16N...AND UPPER RIDGING EXTENDS FROM THE GULF OF TEHUANTEPEC AREA TO JUST SOUTH OF THE BAJA PENINSULA. LIGHT TO MODERATE DEEP LAYER EAST SHEAR PERSISTS ACROSS THE LOW NEAR 13N99W...ALTHOUGH THIS WILL LIKELY WEAKEN AS AN UPPER TROUGH DIGS INTO THE NORTHERN BAJA AREA THROUGH THU. THE GAP WINDS TROUGH THE TEHUANTEPEC AREA ARE EXPECTED TO PERSIST FOR ANOTHER DAY OR SO DUE TO SLIGHTLY DRIER AND COOLER AIR OVER THE GULF OF MEXICO CONTINUING TO PUSH SOUTHWARD THROUGH THE ISTHMUS OF TEHUANTEPEC. MEANWHILE SOUTHERLY SWELL CONTINUES GENERALLY W OF THE GALAPAGOS AND S OF 18N. W OF 110W... THE TRACK AND DEVELOPMENT OF T.S MARIE CONTINUES TO BE THE MAIN FORECAST CONCERN. THE PRESSURE GRADIENT IS TIGHTENING BETWEEN MARIE AND HIGH PRES 1018 MB NEAR 28N130W. SCATTEROMETER DATA SHOW A BROAD SWATH OF 20 KT WINDS BETWEEN THESE TWO SYSTEMS...AND STRONGER WINDS ARE LIKELY TODAY IN THIS AREA AS MARIE MOVES FURTHER WEST. 8 TO 10 FT SWELL CONTINUES TO PUSH INTO THE AREA FROM THE NORTHWEST AS WELL...ALLOWING FOR CONFUSED SEAS IN THE AREA TO THE NW OF MARIE. FURTHER SOUTH...A WEAK STATIONARY SURFACE TROUGH NEAR 136W WILL DISSIPATE OVER THE NEXT DAY. $$ CHRISTENSEN