000 AXPZ20 KNHC 060935 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON OCT 06 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 NORBERT IS LOCATED NEAR 14.1N 103.9W AT 06/0900 UTC OR ABOUT 300 NM SOUTH OF MANZANILLO MEXICO MOVING W OR 270 DEG AT 6 KT. ESTIMATED MINIMUM CENTRAL PRES 993 MB. MAXIMUM SUSTAINED WIND SPEED 55 WITH GUSTS TO 65 KT. REFER TO LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC AND INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP5/ WTPZ35 KNHC FOR MORE DETAILS. NORBERT CONTINUES TO GRADUALLY DEVELOP AS EVIDENCED BY LATEST SATELLITE IMAGERY...WHICH SHOWS A TIGHT BALL OF CONVECTION OVER THE CENTER ALONG WITH A WEAK BANDING FEATURE OFF TO THE W. ALTHOUGH CIMSS ANALYSES CONTINUE TO DIAGNOSE MODERATE ESE SHEAR OVER NORBERT...THE EXPECTATION IS THAT NORBERT SHOULD GAIN HURRICANE STRENGTH LATER TODAY AS IT MOVES ON A MOSTLY W TO WNW TRACK. TROPICAL STORM MARIE IS LOCATED NEAR 18.5N 123.0W AT 06/0900 UTC OR ABOUT 775 NM WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA AND MOVING LITTLE. ESTIMATED MINIMUM CENTRAL PRES 1004 MB. MAXIMUM SUSTAINED WIND SPEED 35 WITH GUSTS TO 45 KT. REFER TO LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC AND INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP4/WTPZ34 KNHC FOR MORE DETAILS. DEEP CONVECTION ASSOCIATED WITH MARIE CONTINUES TO DIMINISH...AS THE TROPICAL CYCLONE MOVES OVER 25-26C SEA SURFACE TEMPERATURES. WHAT CONVECTION REMAINS IS LOCATED MAINLY OVER THE NORTHERN SEMICIRCLE ANDS SEEMS TO BE FOLLOWING THE MID-LEVEL CENTER BEING PUSHED OFF TO THE W FASTER THAN THE LOW-LEVEL CENTER. WITH THE LOW- AND MID-LEVEL CENTERS DECOUPLING AND CONVECTION FURTHER DIMINISHING...MARIE IS EXPECTED TO WEAKEN TO A TROPICAL DEPRESSION TODAY AND A REMNANT LOW WITHIN THE NEXT DAY OR TWO. AN AREA OF LOW PRES 1007 MB IS ESTIMATED TO LIE CLOSE TO 12N89W ...WITH LITTLE MOVEMENT DETECTED. CIMSS ANALYSES SUGGEST MODERATE EASTERLY SHEAR AFFECTING THIS SYSTEM...WHICH SEEMS TO MAKE SENSE GIVEN THE APPARENT EXPOSED LOW-LEVEL CIRCULATION LYING E OF THE NEAREST DEEP CONVECTION. ALTHOUGH THE ENVIRONMENT DOES NOT APPEAR IDEAL FOR DEVELOPMENT...SEVERAL GLOBAL MODELS SUGGEST THAT GENESIS IS POSSIBLE AS THE AREA MOVES ON A MOSTLY NW COURSE AT 5 TO 10 KT OVER THE NEXT FEW DAYS. ...ITCZ... ITCZ AXIS ALONG 12N87W TO 11N95W TO 14N104W TO 07N109W TO 12N128W TO 09N140W. NO ORGANIZED CONVECTION NEAR ITCZ. ...DISCUSSION... A GAP WIND EVENT IN THE GULF OF TEHUANTEPEC APPEARS TO HAVE COME TO A CLOSE...THOUGH THERE HAVE BEEN NO RECENT MICROWAVE DATA TO SUPPORT THIS CONCLUSION. AS A DEEP TROUGH OVER THE WESTERN STATES DIGS INTO THE PLAINS EARLY THIS WEEK...A COLD FRONT FOLLOWED BY STRENGTHENING HIGH PRESSURE SHOULD BUILD ACROSS THE GULF AND NORTHERN MEXICO. MODEL GUIDANCE SUGGESTS THAT THE HIGH SHOULD BUILD INTO THE ISTHMUS OF TEHUANTEPEC LATER TUE AND WED AT THE SAME TIME THAT LOW PRESSURE APPROACHES THE REGION FROM THE SE. AS A RESULT...A NEW GAP WIND EVENT MAY DEVELOP BY WED...WITH ITS STRENGTH AND DURATION LIKELY TIED TO WHETHER THE TRACK AND INTENSITY OF SURFACE LOW PRESSURE NEARING THE GULF OF TEHUANTEPEC FROM THE SE. ELSEWHERE...A WELL-DEFINED SWELL TRAIN FROM A NORTHWESTERLY GALE EVENT OVER THE NE PACIFIC FRI AND SAT IS SPREADING INTO THE NORTHWEST HALF OF THE AREA. RECENT SHIP REPORTS AND MODEL GUIDANCE INDICATE SEAS OF 8 TO 11 FT N OF 10N AND W OF A LINE FROM 27N115W TO 10N130W...WITH THE SWELL SPREADING SE. AS THE SWELL MOVE FARTHER AND FARTHER AWAY FROM THE ORIGIN...EXPECT SEAS TO GRADUALLY SUBSIDE EARLY THIS WEEK FROM NW TO SE. FINALLY...THE CONTINUED ARRIVAL OF LONG PERIOD SW SWELL OVER THE SW HALF OF THE BASIN CONTINUES. OUTSIDE OF THE INFLUENCE OF ACTIVE TROPICAL CYCLONES...NOAA WAVEWATCH GUIDANCE INDICATES SEAS OF UP TO 9 FT IN SW SWELL FROM 06N TO 18N AND E OF 113W THROUGH EARLY THIS WEEK. $$ KIMBERLAIN