000 AXPZ20 KNHC 290930 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT SEP 29 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION NORMAN CENTERED NEAR 25.9N 109.5W AT 29/0900 UTC OR ABOUT 30 MILES WNW OF LOS MOCHIS MEXICO MOVING NW AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. NORMAN HAD TEMPORARILY MOVED INLAND SEVERAL HOURS AGO ALTHOUGH IT IS NOW RE-EMERGING INTO THE GULF OF CALIFORNIA. CONVECTION HAS RAPIDLY DIMINISHED WITH NO DEEP CONVECTION REMAINING AND NORMAN IS FORECAST TO DISSIPATE TONIGHT. NORMAN IS EXPECTED TO PRODUCE ADDITIONAL RAINFALL ACCUMULATIONS OF 1 TO 2 INCHES ACROSS THE MEXICAN STATES OF SINALOA AND FAR WESTERN DURANGO THROUGH TODAY. ISOLATED STORM TOTAL AMOUNTS OF 12 INCHES ARE POSSIBLE IN ASSOCIATION WITH NORMAN. THESE RAINFALL AMOUNTS MAY PRODUCE LIFE-THREATENING FLASH FLOODS AND MUDSLIDES. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 09N80W TO 11N88W TO 09N100W TO 15N115W TO 09N130W TO 10N136W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N136W TO 09N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE MONSOON TROUGH E OF 83W. SIMILAR CONVECTION IS FROM 06N TO 09N BETWEEN 90W AND 93W. ...DISCUSSION... POST-TROPICAL REMNANT LOW MIRIAM CONTINUES TO LINGER NEAR 21N115W AT 1007 MB. EARLIER SCATTEROMETER PASSES INDICATE THAT ASSOCIATED WINDS HAVE DIMINISHED TO 20 KT OR LESS ALTHOUGH A LINGERING POCKET OF SW SWELL TO 9 FT IS WITHIN 240 NM IN THE E AND 300 NM IN THE S QUADRANTS OF MIRIAM. THE REMNANT SURFACE LOW IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH THE NEXT FEW DAYS WHILE THE AREA OF SWELL SUBSIDES TO LESS THAN 8 FT BY EARLY SUN MORNING. A WEAKENING COLD FRONT EXTENDING FROM 40N130W TO 34N138W TO 34N144W BISECTS SUBTROPICAL HIGH PRES NW OF THE AREA INTO TWO HIGH PRES CELLS...CENTERED NEAR 42N136W AND 31N143W RESPECTIVELY. A SET OF LONG PERIOD NW SWELL TO 9 FT ASSOCIATED WITH THIS FRONT HAS BREACHED THE NW CORNER OF THE DISCUSSION WATERS CURRENTLY W OF A LINE FROM 30N133W TO 27N140W. THIS SWELL WILL GRADUALLY PROPAGATE E-SE...BUILDING TO 10 FT BY EARLY SUN MORNING...THEN WILL BEGIN TO DECAY TO LESS THAN 8 FT EARLY MON MORNING. MEANWHILE...THE SUBTROPICAL HIGH WILL STRENGTHEN TODAY AND WILL SHIFT WELL N OF THE AREA...TO W OF OREGON NEAR 43N133W ON SUN. THIS WEAK RIDGE PATTERN WILL SUPPORT MODERATE N-NE TRADE WINDS OVER MOST OF THE REGION N OF 16N W OF 120W THROUGH THE WEEKEND. SOUTHWESTERLY MONSOONAL FLOW S OF THE MONSOON TROUGH OVER THE CENTRAL PORTION OF THE AREA HAS WEAKENED WITH S-SW WINDS DIMINISHING TO 15-20 KT AT BEST. HOWEVER LINGERING CROSS- EQUATORIAL SW SWELL TO 9 FT REMAINS OVER THE S CENTRAL WATERS AND THIS SWELL WILL SLOWLY SUBSIDE TO 8 FT WHILE ONLY COVERING THE AREA S OF 02N BETWEEN 100W AND 130W BY EARLY MON MORNING. MONSOONAL FLOW IS FORECAST TO STRENGTHEN S OF THE MONSOON TROUGH TO 20 TO 25 KT S OF 10N95W TO 07N105W BY EARLY MON. $$ LEWITSKY