000 AXPZ20 KNHC 110923 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0800 UTC. ...SPECIAL FEATURES... HURRICANE JOVA CENTERED NEAR 17.5N 105.9W AT 11/0900 UTC MOVING N-NE OR 030 DEG AT 5 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 963 MB. MAXIMUM SUSTAINED WIND SPEED IS 100 KT WITH GUSTS TO 120 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION LIES WITHIN 90 NM S SEMICIRCLE OF JOVA WITH SCATTERED MODERATE TO STRONG CONVECTION ELSEWHERE WITHIN 180 NM NW SEMICIRCLE. THE LATEST NHC ADVISORY FORECASTS JOVA TO CONTINUE TO GRADUALLY WEAKEN AS IT MOVES N-NE INTO MEXICO TONIGHT...THEN WEAKEN MORE RAPIDLY AS IT TAKES A NORTHWARD TURN...DISSIPATING BY FRI. 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 WHERE THE CENTER MAKES LANDFALL. TROPICAL DEPRESSION IRWIN CENTERED NEAR 15.2N 115.5W AT 11/0900 UTC MOVING E OR 080 DEG AT 7 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 WITH ISOLATED STRONG CONVECTION LIES WITHIN 110 NM N QUADRANT AND 180 NM SE SEMICIRCLE OF CENTER. LATEST NHC FORECAST SHOWS LITTLE CHANGE IN INTENSITY AS IT CONTINUES TO THE E-NE THROUGH 72 HOURS WITH A SHIFT TO THE SE OVER THE WEEKEND AS IRWIN GRADUALLY DISSIPATES. A 1006 MB LOW LOCATED NEAR 12N94W IS DRIFTING NE. THE CONVECTION ASSOCIATED WITH THE LOW IS DISPLACED TO THE SW AS THE LOW REMAINS UNDER NORTHEASTERLY SHEAR. SCATTERED MODERATE CONVECTION IS FOUND WITHIN 180 NM SW QUADRANT OF THE LOW. UPPER LEVEL WINDS COULD BECOME A LITTLE MORE CONDUCIVE TO DEVELOPMENT OVER THE NEXT 48 HOURS AND THERE IS A CHANCE THIS LOW WILL BECOME A TROPICAL CYCLONE DURING THAT TIME. 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 AXIS EXTENDS FROM 14N91W TO LOW PRES NEAR 12N94W THEN RESUMES FROM 13N118W TO 10N124W TO 10N140W. SCATTERED MODERATE TO STRONG CONVECTION LIES WITHIN 120 NM OF COAST BETWEEN 86W AND 101W. CONVERGENCE AT THE SURFACE ALONG THE TROUGH AXIS COUPLED WITH UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER RIDGE AXIS STEMMING FROM AN ANTICYCLONE NEAR 16N95W AND EXTENDING SE ALONG THE COAST TO THE GULF OF FONSECA ARE ENHANCING THE CONVECTION HERE. ...DISCUSSION... THE 1022 MB SUBTROPICAL HIGH PRES IS CENTERED W OF THE AREA NEAR 29N142W WITH A RIDGE AXIS EXTENDING E TO 29N129W THEN TURNS SE TO 23N115W. TO THE SE LIES A BROAD AREA OF LOW PRES THAT SPANS ACROSS CENTRAL AMERICAN AND WESTERN MEXICO INTO THE ADJACENT CARIBBEAN AND PACIFIC INCLUDING T.D. 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. AS HURRICANE JOVA APPROACHES THE COAST...EXPECT THE PRES GRADIENT TO ALSO TIGHTEN OVER THE GULF OF CALIFORNIA WHERE FRESH N TO NW WINDS ARE EXPECTED TO BEGIN LATER TODAY...INCREASE TO STRONG OVERNIGHT TONIGHT AND DIMINISH TO FRESH WHILE SHIFTING INTO THE NORTHERN GULF BY EARLY THU. 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 LOW PRES SYSTEM NEAR 12N94W. THE 0416 UTC ASCAT PASS MISSED THE LOW...REVEALING SOLID 20 KT SW TO W WINDS WELL SW AND W OF THE CENTER. 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. SEAS CONTINUE TO REMAIN CHAOTIC OVER CENTRAL WATERS WHERE NW SWELL FROM THE FRONTAL SYSTEMS TO THE N...CROSS-EQUATORIAL SW SWELL...AND NE SWELL LINGERING FROM THE DIMINISHED TRADE WINDS ARE MERGING IN THE VICINITY OF HURRICANE JOVA AND T.D. IRWIN. A NEW PULSE OF NW SWELL IS CURRENTLY PROPAGATING THROUGH THE AREA N OF 20N AND WILL HELP KEEP SEAS TO 9 FT OVER N CENTRAL WATERS WHERE THE AFOREMENTIONED FRESH N WINDS ARE IN PLACE. MEANWHILE...A NEW BATCH OF SW SWELL WILL MOVE INTO SOUTHERN WATERS TODAY AND RAISE SIGNIFICANT WAVE HEIGHTS TO 8 TO 10 FT IN AREAS S OF THE MONSOON TROUGH WHERE WINDS ARE NOT FRESH OR STRONGER. $$ SCHAUER