000 AXPZ20 KNHC 110316 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE OCT 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0230 UTC. ...SPECIAL FEATURES... HURRICANE JOVA CENTERED NEAR 17.4N 106.0W AT 11/0300 UTC MOVING N-NE OR 030 DEG AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 135 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. JOVAS EARLIER WELL-DEFINED EYE HAS FILLED IN DURING THE PAST SEVERAL HOURS INDICATING SLIGHT WEAKENING. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 75-90 NM OF THE CENTER...WITH SCATTERED MODERATE CONVECTION ELSEWHERE FROM 15.5N TO 21N BETWEEN 104W AND 109W. THE LATEST NHC ADVISORY FORECASTS JOVA TO WEAKEN SLIGHTLY YET MAINTAIN MAJOR HURRICANE STRENGTH PRIOR TO LANDFALL TUE AFTERNOON OR EVENING...WITH RAPID WEAKENING EXPECTED THEREAFTER OVER THE MOUNTAINOUS TERRAIN OF W CENTRAL MEXICO. 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. ALSO...DANGEROUS STORM SURGE IS EXPECTED TO PRODUCE SIGNIFICANT COASTAL FLOODING NEAR AND TO THE E OF THE CENTER LANDFALL LOCATION. DOWNGRADED TROPICAL DEPRESSION IRWIN CENTERED NEAR 15.0N 116.3W AT 11/0300 UTC MOVING E OR 085 DEG AT 6 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 MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS BETWEEN 60-120 NM IN THE NE SEMICIRCLE AND WITHIN 60-75 NM IN THE SW SEMICIRCLE OF IRWIN. IRWIN HAS BEEN DOWNGRADED TO A TROPICAL DEPRESSION WHILE CONTINUALLY BEING INFLICTED ON BY UPPER EASTERLY SHEAR. IT IS ALSO BEING AFFECTED BY STABLE AIR FILTERING INTO IT FROM THE W. LATEST NHC FORECAST MAINTAINS DEPRESSION STRENGTH AS IT CONTINUES TO THE E-NE THROUGH 72 HOURS WITH A SHIFT TO THE E-SE FROM 96-120 HOURS. A 1006 MB LOW LOCATED NEAR 12N94.5W IS DRIFTING N. THE CONVECTION ASSOCIATED WITH THE LOW REMAINS DISPLACED TO THE W AS THE LOW REMAINS UNDER NORTHERLY SHEAR. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 10N TO 14N BETWEEN 95W AND 99W WITH SCATTERED MODERATE CONVECTION ELSEWHERE FROM 07N TO 14.5N BETWEEN 95W AND 102W. ONLY 15-20 KT WINDS ARE OCCURRING IN THE N SEMICIRCLE WHILE A LARGE SWATH OF SW-W 20-25 KT WINDS ARE TO THE S FROM FROM 05N TO 12N BETWEEN 85W AND 100W WITH RESULTANT SEAS OF 8-12 FT IN SW SWELL. THIS LOW STILL HAS A MEDIUM CHANCE OF TROPICAL CYCLONE DEVELOPMENT DURING THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...THE AREA OF SW MONSOONAL FLOW WILL PERSIST THROUGH 48 HOURS WHILE SHIFTING SLIGHTLY W TO W OF 86W. INTERESTS ALONG THE PACIFIC COASTS OF SOUTHERN MEXICO... GUATEMALA...EL SALVADOR...HONDURAS...AND NICARAGUA SHOULD CONTINUE TO MONITOR THE PROGRESS OF THIS SYSTEM. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 14N91W TO 1006 MB LOW PRES NEAR 12N94.5W WHERE THERE IS A BREAK IN THE TROUGH DUE TO THE CIRCULATIONS OF HURRICANE JOVA AND TROPICAL STORM IRWIN. THE MONSOON TROUGH RESUMES FROM 13N118W TO 10N125W TO 08N139W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N139W TO BEYOND 09N140W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 10N TO 14N BETWEEN 95W AND 99W...AND SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 07N TO 14.5N BETWEEN 95W AND 102W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS ALSO WITHIN 60-90 EITHER SIDE OF A LINE FROM 07N82W TO 11N92W. ...DISCUSSION... 1021 MB SUBTROPICAL HIGH PRES IS CENTERED W OF THE AREA NEAR 30N143W WITH A RIDGE AXIS EXTENDING E-SE TO NEAR 22N113W. TO THE SE LIES A COMBINED BROAD AREA OF LOW PRES THAT SPANS ACROSS MEXICO AND CENTRAL AMERICA INTO THE ADJACENT GULF OF MEXICO... CARIBBEAN AND PACIFIC INCLUDING TROPICAL DEPRESSION IRWIN AND HURRICANE JOVA. THIS RIDGE CONTINUES TO BE ERODED AS IRWIN AND JOVA MAKE THEIR WAY TO THE E-NE. THE PRES GRADIENT BETWEEN THIS RIDGE AND INCREASINGLY LOWER PRES OVER NW MEXICO IS GENERATING A SMALL AREA OF FRESH N WINDS OVER N CENTRAL FORECAST WATERS N OF 27N BETWEEN 120W AND 128W ALONG WITH 8 FT SEAS IN NW SWELL. AS HURRICANE JOVA MOVES CLOSER TO THE W CENTRAL MEXICO COAST EXPECT THE PRES GRADIENT TO ALSO TIGHTEN OVER THE GULF OF CALIFORNIA WHERE FRESH N TO NW WINDS ARE EXPECTED TO BEGIN EARLY TUE PERSISTING THROUGH AT LEAST WED NIGHT...BECOMING STRONG NEAR THE END OF THAT TIME PERIOD. FRESH SOUTHWESTERLY MONSOON FLOW DOMINATES THE AREA S OF THE THREE SPECIAL FEATURES NOTED ABOVE. THE PRES GRADIENT IS STRONGEST BETWEEN HIGH PRES OVER THE EASTERN SOUTH PACIFIC AND THE AFOREMENTIONED BROAD LOW PRES OVER CENTRAL AMERICA EXTENDING W TO ENCOMPASS IRWIN AND JOVA. EARLIER SCATTEROMETER PASSES SHOWED A LARGE AREA OF FRESH TO STRONG WINDS SPANNING MUCH OF THE REGION S OF THE MONSOON TROUGH. THESE WINDS ARE EXPECTED TO MERGE WITH THE LOW PRES DISCUSSED IN THE SPECIAL FEATURES SECTION AS PRESSURES FALL ALONG THE MONSOON TROUGH AND AROUND THIS LOW. THE STRENGTHENING SW FLOW OVER THE EASTERN WATERS WILL MAINTAIN LOW LEVEL CONFLUENCE AND CONTINUE TO PRODUCE ACTIVE CONVECTION NEAR THE MONSOON TROUGH. SEAS CONTINUE TO REMAIN CHAOTIC OVER THE CENTRAL WATERS WHERE NW SWELL FROM THE FRONTAL SYSTEMS TO THE N...CROSS-EQUATORIAL SW SWELL...AND NE SWELL FROM THE DIMINISHING TRADE WINDS ARE MERGING IN THE VICINITY OF HURRICANE JOVA AND TROPICAL DEPRESSION IRWIN. A NEW PULSE OF NW SWELL WILL ENTER THE NW CORNER IN 24 HOURS ENCOMPASSING THE AREA N OF 20N W OF 120W IN 48 HOURS WITH SEAS UP TO 10 FT BY THAT TIME. MEANWHILE...A NEW BATCH OF S-SW SWELL IS FORECAST TO MOVE INTO SOUTHERN WATERS TUE AND WILL RAISE SIGNIFICANT WAVE HEIGHTS TO 8 TO 10 FT IN THE AREAS S OF THE MONSOON TROUGH. $$ LEWITSKY