000 AXPZ20 KNHC 120943 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC WED OCT 12 2011 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 0815 UTC. ...SPECIAL FEATURES... HURRICANE JOVA CENTERED NEAR 19.9N 105.1W AT 12/0900 UTC MOVING N OR 05 DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION LIES WITHIN 120 NM OF JOVA. JOVA IS FORECAST TO REMAIN INLAND BUT CONTINUE TO THE N...PARALLELING THE COAST. THE OFFICIAL NHC FORECAST CALLS FOR JOVA TO DIMINISH TO A TROPICAL STORM TODAY AND TO A DEPRESSION THU. VERY HEAVY RAINFALL AMOUNTS OF 6-12 INCHES WITH ISOLATED AMOUNTS TO 20 INCHES WILL RESULT IN FLASH FLOODING AND LIFE-THREATENING MUDSLIDES. LARGE AND DANGEROUS SWELLS WILL CONTINUE TO PROPAGATE TO THE W CENTRAL MEXICO COASTLINE RESULTING IN LIFE-THREATENING RIP CURRENTS TODAY. ALSO...DANGEROUS STORM SURGE IS EXPECTED TO PRODUCE SIGNIFICANT COASTAL FLOODING TODAY NEAR AND TO THE E OF WHERE THE CENTER MAKES LANDFALL. TROPICAL STORM IRWIN CENTERED NEAR 15.2N 112.3W AT 12/0900 UTC MOVING E-NE OR 075 DEG AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION LIES WITHIN 45 NM OF CENTER EXCEPT 210 NM N QUADRANT OF IRWIN. THE LATEST NHC FORECAST DIMINISHES IRWIN TO A DEPRESSION BY THU MORNING AS IT CONTINUES EASTWARD THROUGH 72 HOURS WITH TURN BACK TO THE WEST THEREAFTER AS IRWIN GRADUALLY DISSIPATES. NEWLY FORMED TROPICAL DEPRESSION TWELVE-E CENTERED NEAR 14.7N 93.6W AT 12/0900 UTC MOVING N OR 360 DEG AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ32 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 210 NM OF CENTER EXCEPT 90 NM NE QUADRANT OF TWELVE-E. THE LATEST NHC FORECAST INTENSIFIES THE SYSTEM TO A TROPICAL STORM TODAY AND MOVES THE SYSTEM INLAND INTO FAR SOUTHERN MEXICO OVERNIGHT TONIGHT. RAINFALL ACCUMULATIONS OF 5 TO 10 INCHES ARE EXPECTED OVER SOUTHERN MEXICO AND WESTERN GUATEMALA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 13N117W TO 08N140W. NO SIGNIFICANT CONVECTION LIES ALONG THE AXIS. ...DISCUSSION... THE 1023 MB SUBTROPICAL HIGH PRES IS CENTERED JUST N OF THE AREA NEAR 32N134W WITH A RIDGE AXIS EXTENDING E TO 29N129W THEN TURNS SE TO 22N111W. TO THE SE LIES A BROAD AREA OF LOW PRES THAT SPANS ACROSS CENTRAL AMERICA N OF NICARAGUA AND WESTERN MEXICO INTO THE ADJACENT NW CARIBBEAN AND EASTERN PACIFIC INCLUDING T.S. IRWIN AND HURRICANE JOVA. THIS RIDGE CONTINUES TO BE ERODED AS IRWIN AND JOVA MAKE THEIR WAY TO THE E-NE. TRADES HAVE DIMINISHED AS A RESULT OF THE WEAKENED RIDGE. HOWEVER...THE PRES GRADIENT BETWEEN THIS RIDGE AND LOWER PRES OVER NW MEXICO IS GENERATING A SMALL AREA OF FRESH N WINDS OVER N CENTRAL FORECAST WATERS AND FRESH N TO NW WINDS OVER THE GULF OF CALIFORNIA. THESE WINDS ARE EXPECTED TO DIMINISH THU AS JOVA AND IRWIN WEAKEN. FRESH SOUTHWESTERLY MONSOON FLOW DOMINATES THE AREA S OF THE THREE SPECIAL FEATURES NOTED ABOVE. THE 0536 UTC AND 0356 UTC ASCAT PASSES SHOW A VAST EXPANSE OF FRESH TO STRONG WINDS OVER MUCH OF THE REGION S OF THESE TROPICAL CYCLONES AND THE MONSOON TROUGH E OF 120W. THESE WINDS WILL DIMINISH AS THE THREE TROPICAL CYCLONES WEAKEN. THE 0536 UTC ASCAT PASS INDICATES A BROAD AREA OF LOW PRES TRYING TO ORGANIZE ALONG THE MONSOON TROUGH AROUND 129W. A NEW LOW PRES SYSTEM IS EXPECTED TO DEVELOP HERE ALONG THE MONSOON TROUGH BY THU AND WILL TRACK NORTHEASTWARD. SEAS CONTINUE TO REMAIN CHAOTIC OVER CENTRAL WATERS WHERE NW SWELL FROM THE FRONTAL SYSTEMS TO THE N AND CROSS-EQUATORIAL SW SWELL ARE MERGING IN THE VICINITY OF T.S. IRWIN. A PULSE OF NW SWELL WITH SEAS OVER 8 FT IS CURRENTLY PROPAGATING THROUGH THE AREA N OF 23N INCLUDING THE AREA WHERE THE AFOREMENTIONED FRESH N WINDS ARE IN PLACE OVER N CENTRAL WATERS. A NEW NW SWELL TRAIN IS ALSO MAKING ITS WAY THROUGH NW WATERS WITH SEAS AS HIGH AS 11 FT. MEANWHILE...A NEW BATCH OF 16-18 SECOND PERIOD SW SWELL HAS MOVED INTO SOUTHERN WATERS TODAY AND RAISED SIGNIFICANT WAVE HEIGHTS TO 8 TO 10 FT IN AREAS S OF THE MONSOON TROUGH WHERE WINDS ARE NOT FRESH OR STRONGER. THIS SWELL WILL GRADUALLY DAMPEN AS IT MAKES ITS WAY INTO CENTRAL WATERS. $$ SCHAUER