000 AXPZ20 KNHC 082203 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT OCT 08 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...SPECIAL FEATURES... NEWLY DOWNGRADED TROPICAL STORM IRWIN WAS CENTERED NEAR 14.4N 120.9W AT 2100 UTC MOVING N OR 360 DEG AT 1 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. OUTFLOW FROM THE WIDESPREAD CONVECTION ASSOCIATED WITH HURRICANE JOVA TO THE E HAS CONTINUED TO PRODUCE ELY WIND SHEAR IMPINGING UPON IRWIN...LEAVING A COMPLETELY EXPOSED LLVL CIRCULATION VOID OF DEEP CONVECTION THIS AFTERNOON. IRWIN IS EXPECTED TO MOVE LITTLE OVER THE NEXT 24 HOURS...BUT THEREAFTER IS FORECAST TO MOVE E-NE IN THE GENERAL DIRECTION OF W CENTRAL MEXICO THROUGH 120 HOURS. IRWIN IS FORECAST TO MAINTAIN ITS CURRENT INTENSITY THROUGH 24 HOURS THEN STRENGTHEN SLIGHTLY THROUGH WED. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS OCCURRING FROM 70 TO 240 NM ACROSS THE W SEMICIRCLE OF IRWIN. NEWLY UPGRADED HURRICANE JOVA WAS CENTERED NEAR 16.0N 110.2W AT 2100 UTC MOVING E-NE OR 75 DEG AT 3 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 989 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. MICROWAVE IMAGERY TODAY HAS SHOWN THE DEVELOPMENT OF INNER CORE EYE WALL...SUGGESTING A HURRICANE. JOVA IS EXPECTED TO BEGIN CONTINUE MOVING E-NE TOWARD W CENTRAL MEXICO WITH THE CURRENT FORECAST INDICATING JOVA WILL INLAND ON TUE. ADDITIONAL STRENGTHENING IS FORECAST UNTIL LANDFALL. NUMEROUS MODERATE TO STRONG CONVECTION WAS OCCURRING WITHIN 150 NM OF JOVA WITH SCATTERED MODERATE CONVECTION ELSEWHERE WITHIN 300 NM ACROSS THE W SEMICIRCLE. A 1008 MB LOW PRES CENTERED NEAR 11.5N97.5W CONTINUES TO PRODUCE INTERMITTENT BUSTS OF SIGNIFICANT CONVECTION TODAY...AND HAS BEEN DRIFTING NW OVER THE PAST 24 HOURS. HOWEVER THE LOW IS EXPECTED TO BECOME STATIONARY OVERNIGHT AND BEGIN MOVING EAST TO NORTHEASTWARD SUN THROUGH MON. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 150 NM OF THE LOW PRES CENTER. ATMOSPHERIC CONDITIONS APPEAR CONDUCIVE FOR ADDITIONAL DEVELOPMENT OF THIS SYSTEM...AND THERE IS A GOOD CHANCE IT MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH ALONG 09N84W TO 1008 MB LOW PRES 11N97W TO 12N101W WHERE THERE IS A BREAK IN THE TROUGH DUE TO THE CIRCULATION AROUND TROPICAL STORM IRWIN AND HURRICANE JOVA. THE MONSOON TROUGH THEN RESUMES FROM 13N125W TO 08N136W. THE ITCZ AXIS EXTENDS FROM 08N136W TO 08N140W. SCATTERED MODERATE ISOLATED STRONG FROM 06N TO 09N E OF 85W. SIMILAR CONVECTION IS FROM 07N TO 13N BETWEEN 96W AND 100W. ...DISCUSSION... 1029 MB HIGH PRES IS CENTERED N OF THE AREA NEAR 34N136W WITH A RIDGE AXIS EXTENDING SE TO NEAR 21N112W. THE PRES GRADIENT BETWEEN THIS RIDGE AND LOWER PRES ASSOCIATED WITH HURRICANE IRWIN AND TROPICAL STORM JOVA CONTINUES TO PRODUCE FRESH NE TRADES FROM 17N TO 22N W OF 117W...WHICH HAS SHRUNKEN SLIGHTLY SOUTHWARD DURING THE PAST 12 HOURS. THESE TRADES ARE EXPECTED TO SHRINK TONIGHT THROUGH SUNDAY ACROSS W PORTIONS AS THE SUBTROPICAL HIGH REORGANIZES FURTHER TO THE SW DUE TO A PROGRESSIVE COLD FRONT IMPINGES UPON IT FROM THE N. IN ADDITION...THE PRES GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER INLAND MEXICO IS MAINTAINING FRESH NW TO N WINDS OVER THE GULF OF CALIFORNIA N OF 25N WHICH WILL PERSIST THROUGH THE NEXT 48 HOURS AS WELL AS WITHIN 120 NM OF THE W COAST OF BAJA CALIFORNIA. WINDS W OF THE BAJA PENINSULA ARE EXPECTED TO DIMINISH LATE TONIGHT AND SUNDAY AS THE SUBTROPICAL HIGH BEGINS TO SHIFT WESTWARD AND THE PRES GRADIENT RELAXES. WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A STRONG UPPER LEVEL TROUGH MOVING QUICKLY E-SE ACROSS THE NE PACIFIC NEAR 135W...AND IS EXPECTED TO REACH THE W COAST OF N AMERICA BY SUNDAY MORNING...AND EXTEND SW TO NEAR 21N140W. AS THIS TROUGH CONTINUES EWD SUN AND MON ACROSS THE WRN U.S. AND NRN MEXICO...IT WILL ACT TO NUDGE THE TWO TROPICAL CYCLONES ON AN ENE TO NE TRAJECTORY AS INDICATED BY THE GLOBAL MODELS...AND REFLECTED IN THE FORECASTS FOR IRWIN AND JOVA. MONSOONAL FLOW DOMINATES THE REMAINDER OF THE AREA WITH THE THREE TROPICAL SYSTEMS NOTED ABOVE ORIGINATING WITHIN THE MONSOON TROUGH. IRWIN AND JOVA REMAIN EMBEDDED WITHIN THE WESTERN END OF THIS MONSOONAL CIRCULATION...WHILE THE LOW CENTER NEAR 11.5N97.5W IS EMBEDDED WITHIN THE W PORTION OF A MONSOONAL GYRE WHICH IS ANCHORED BY A BROAD AND WEAK LLVL CYCLONIC CIRCULATION ACROSS THE EXTREME SW CARIBBEAN. SW TO W FLOW OF 20 TO LOCALLY 25 KT IS EXPECTED TODAY FROM THE MONSOON TROUGH S TO ABOUT 05N FROM ABOUT 98W EWD TO PANAMA AND COLOMBIA....WHICH WILL MAINTAIN LLVL CONFLUENCE AND CONTINUE TO PRODUCE ACTIVE CONVECTION ACROSS THIS ZONE. THIS ENHANCED SWLY FLOW IS EXPECTED TO CREATE FAVORABLE CONDITIONS FOR INCREASED CONVECTION AND ORGANIZATION OF THE LOW AT 11N97W. NW SWELL IS CONTINUING TO PROPAGATE THROUGH THE NORTHERN FORECAST WATERS AND IS MERGING WITH THE 15-17 PERIOD CROSS-EQUATORIAL SW SWELL OVER CENTRAL WATERS INCLUDING THE AREA NEAR JOVA AND IRWIN...WHERE COMBINED SEAS ARE AS HIGH AS 12 FT. THIS MERGING SWELL COMBINED WITH SWLY WIND WAVES DEVELOPING WITHIN THE MONSOONAL SW FLOW IS CREATING A VERY CONFUSED SEA STATE ACROSS CENTRAL WATERS THAT IS EXPECTED TO PERSIST THROUGH THE WEEKEND. A NEW PULSE OF NW SWELL WILL PROPAGATE INTO THE FORECAST AREA BY EARLY SUN...WITH SEAS EXPECTED TO BUILD TO 8 FT OVER N CENTRAL FORECAST WATERS. $$ STRIPLING