000 AXPZ20 KNHC 012109 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED OCT 01 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURES... TROPICAL STORM MARIE IS NEAR 17.8N 117.4W...APPROXIMATELY 600 MILES...965 KM...SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 01/2100 UTC MOVING 305 DEG AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH HIGHER GUSTS. 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. MARIE IS SITUATED ON THE SOUTHWEST SIDE OF AN UPPER ANTICYCLONE... WHERE DIVERGENT SOUTHEAST FLOW ALOFT IS ENHANCING CONVECTION. EASTERLY SHEAR ON THE ORDER OF 10 TO 20 KT SHOULD BEGIN TO DIMINISH AS SUGGESTED BY THE GLOBAL MODELS. CONSEQUENTLY...MARIE SHOULD STRENGTHEN SLIGHTLY BEFORE ENCOUNTERING COOLER WATERS IN AROUND 24 HOURS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 14N TO 21N BETWEEN 117W AND 122W. A 1008 MB LOW IS CENTERED NEAR 13N98W...OR APPROXIMATELY 320 NM SW OF THE GULF OF TEHUANTEPEC. THE LOW IS SITUATED SOUTH OF AN UPPER RIDGE AXIS...SUPPLYING MODERATE E SHEAR AND CONFINING CONVECTION TO THE WEST OF THE CENTER. STRONG NE SURFACE WINDS OUT OF THE GULF OF TEHUANTEPEC CONTINUE TO CONVERGE INTO THE NORTH SIDE OF THE LOW...WITH MODERATE TO STRONG SW SURFACE WINDS CONVERGING INTO THE LOW ON ITS EAST SIDE. A QUIKSCAT PASS AT 1252Z SHOWS MANY RAIN CONTAMINATED WINDS OF 25-30 KT IN AN ELONGATED PATTERN. EASTERLY SHEAR IS EXPECTED TO WEAKEN OVER THE NEXT COUPLE OF DAYS...ALLOWING THE POSSIBILITY THAT THE LOW MAY INTENSIFY. THUS...THIS LOW HAS A HIGH POTENTIAL FOR TROPICAL CYCLONE FORMATION WITH THE NEXT 48 HOURS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 11N86W 13N100W 12N110W 10N122W 10N125W 11N137W 09N140W. BESIDES THE CONVECTION MENTIONED IN THE SPECIAL FEATURE SECTION...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALONG THE COAST OF COSTA RICA FROM 05N-08N BETWEEN 82W AND 85W...AND FROM 09N TO 12N BETWEEN 85W AND 89W. SCATTERED MODERATE CONVECTION IS IN BETWEEN THE TWO SPECIAL FEATURES FROM 17N TO 20N BETWEEN 108W AND 111W. SCATTERED MODERATE CONVECTION IS FROM 08N TO 10N BETWEEN 138W AND 141W. ...DISCUSSION... E OF 120W... MAIN FORECAST ISSUE FOR AT LEAST THE NEXT COUPLE OF DAYS WILL BE DEVELOPMENT AND TRACK OF TROPICAL STORM MARIE. SEE ABOVE. A 1252Z QUIKSCAT SHOWS A BROAD SWATH OF MODERATE TO STRONG SOUTHWESTERLY WINDS TO THE SOUTH OF THE LOW AT 12N98W CONVERGING INTO THE SYSTEM. QUIKSCAT ALSO SHOWS 20 TO 30 KT NORTHERLY WINDS PERSISTING THROUGH THE GULF OF TEHUANTEPEC...CONVERGING INTO THE LOW NEAR 13N98W. ALOFT...AN UPPER ANTICYCLONE CENTERED NEAR 20N113W WITH A RIDGE AXIS EXTENDING EAST TO GUATEMALA IS PROVIDING MODERATE EASTERLY SHEAR S OF 17N. THE UPPER ANTICYCLONE WILL WEAKEN AS AN UPPER TROUGH DIGS TO THE NORTH OF THE AREA THROUGH THU...ALLOWING THE SHEAR TO DIMINISH. MEANWHILE SOUTHERLY CROSS EQUATORIAL SWELL AROUND 8 FT WILL PUSH AS FAR AS 10N THROUGH THU. W OF 120W... AN UPPER TROUGH IS DIGGING THROUGH 135W N OF 22N. AN ASSOCIATED STATIONARY FRONT EXTENDS FROM 32N129W TO 21N140W. SHIP OBSERVATIONS AND QUIKSCAT DATA SHOW ONLY A SMALL BAND OF 20 KT SOUTH WINDS AHEAD OF THE FRONT N OF 30N. THE FRONT WILL WEAKEN THROUGH TONIGHT AS THE UPPER SUPPORT LIFTS TO THE NE. EVEN AS THE FRONT WASHES OUT...FRESH SWELL UP TO 12 FT IS EXPECTED TO PUSH INTO THE AREA BEHIND THE FRONT AND PROPAGATE TO THE SE. EXPECT AN AREA OF CONFUSED SEAS TONIGHT FROM 12N TO 24N BETWEEN 120W AND 130W AS THE SWELL ENCOUNTERS SEAS RELATED TO T.S. MARIE MIGRATING WESTWARD. FURTHER SOUTH...A STATIONARY AND WEAK 1012 MB LOW IS EMBEDDED ALONG THE ITCZ NEAR 11N137W WITH ONLY MODEST CONVECTION NOTED. $$ FORMOSA