000 AXPZ20 KNHC 101603 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON OCT 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...SPECIAL FEATURES... HURRICANE JOVA CENTERED NEAR 16.3N 106.8W AT 10/1500 UTC MOVING E OR 090 DEG AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 957 MB. MAXIMUM SUSTAINED WIND SPEED IS 110 KT WITH GUSTS TO 135 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED WITHIN 60 NM OF CENTER WITH SCATTERED MODERATE TO STRONG CONVECTION ELSEWHERE FROM 17N-20N BETWEEN 105W-110W. LATEST NHC ADVISORY FORECASTS JOVA TO INTENSIFY SLIGHTLY TODAY AS IT CONTINUES ON AN E-NE MOTION AND THEN TURN MORE NE AS IT APPROACHES CENTRAL MEXICO...WITH LANDFALL ANTICIPATED OVERNIGHT TUE NIGHT INTO WED. LARGE AND DANGEROUS WAVES ASSOCIATED WITH JOVA WILL BEGIN TO REACH THE COASTLINE TODAY. INTERESTS IN AND NEAR W CENTRAL MEXICO SHOULD CAREFULLY MONITOR THE LATEST NHC ADVISORY INFORMATION FOR RELATED WATCHES AND WARNINGS AFFECTING MEXICO. TROPICAL STORM IRWIN CENTERED NEAR 15.0N 117.7W AT 10/1500 UTC MOVING E OR 090 DEG AT 5 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. IRWIN IS UNDER ELY SHEAR ...AND ALSO IS BEING AFFECTED BY STABLE AIR FILTERING INTO IT FROM THE W HAMPERING IT FROM INTENSIFYING ANY TIME SOME. SATELLITE IMAGERY SHOWED SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 80 NM SE AND S OF THE CENTER OF IRWIN. THE LATEST NHC ADVISORY FORECASTS IRWIN TO REMAIN GENERALLY ON A E-NE TRACK THROUGH THE NEXT 48 HRS WITH ONLY A SLIGHT INCREASE IN INTENSITY EXPECTED. A 1006 MB LOW LOCATED NEAR 11N95W IS DRIFTING E. THE CONVECTION ASSOCIATED WITH THE SYSTEM REMAINS DISPLACED TO THE W AS THE LOW IS UNDER NELY SHEAR. CONVECTION ASSOCIATED WITH THE LOW IS OF THE SCATTERED MODERATE TO STRONG TYPE WITHIN 180 NM OF THE LOW IN THE SW AND W QUADRANTS. SCATTERED STRONG CONVECTION IS WITHIN 150 NM OF THE LOW IN THE NW QUADRANT. WINDS ARE 20-25 KT WITHIN 60 NM OF THE LOW CENTER...BUT ARE EXPECTED TO INCREASE TO 30 KT WITHIN 90 NM OF THE LOW BY 48 HRS. FORECAST GUIDANCE SUGGESTS THAT THE UPPER LEVEL WINDS CURRENTLY SHEARING THE CONVECTION AWAY FROM THE LOW LEVEL CENTER SHOULD WEAKEN SOME...ALLOWING FOR SLOW DEVELOPMENT OF THE LOW DURING THE NEXT 48 HOURS AS THE LOW MOVES E-NE. THE LOW HAS A MEDIUM CHANCE OF INTENSIFYING INTO A TROPICAL CYCLONE DURING THIS TIME. INTERESTS ALONG THE PACIFIC COASTS OF SOUTHERN MEXICO...GUATEMALA...EL SALVADOR... HONDURAS...AND NICARAGUA SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS IS ANALYZED FROM 12N87W TO 13N90W TO LOW PRES NEAR 12N95W WHERE IT ENDS DUE TO THE CYCLONIC CIRCULATIONS AROUND HURRICANES JOVA AND IRWIN. IT THEN RESUMES FROM 12N123W TO 11N135W TO 8N140W. SCATTERED MODERATE CONVECTION EXISTS WITHIN 60 NM N AND 180 NM S OF THE AXIS BETWEEN 85W-92W. SCATTERED MODERATE/ISOLATED STRONG IS SEEN FROM 9N-12N BETWEEN 95W-98W. ...DISCUSSION... A LARGE UPPER LEVEL ANTICYCLONE IS NW OF THE DISCUSSION AREA AT 33N144W WITH A RIDGE E TO SRN CALIFORNIA. A NARROW UPPER TROUGH EXTENDS FROM INTERMOUNTAIN U.S. SW TO ACROSS NRN BAJA CALIFORNIA AND TO A COL REGION AT 26N131W. SW OF THE COL REGION...A MID/UPPER TROUGH EXTENDS SOUTHWESTWARD TO A MID/UPPER LEVEL CYCLONIC CIRCULATION W OF THE 140W AT 20N145W. AT THE SURFACE ...A 1022 MB SUBTROPICAL HIGH IS CENTERED NEAR 30N140W WITH A RIDGE ESE TO NEAR 26N123W. SATELLITE WATER VAPOR IMAGERY SHOWS A SWATH OF MODERATE SUBSIDENCE CREATING A RATHER STABLE ATMOSPHERIC ENVIRONMENT REFLECTED AS BROKEN STRATOCUMULUS CLOUDS MOVING SWD TO THE N OF 17N W OF 119W. ELSEWHERE MID/UPPER LEVEL RIDGING COVERS THE AREA...EXCEPT W OF 130W WHERE BROAD CYCLONIC FLOW IS PRESENT. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES ASSOCIATED WITH TROPICAL STORM IRWIN AND HURRICANE JOVA CONTINUES TO PRODUCE FRESH NE TRADES FROM 16N-25N W OF 130W. THESE TRADES ARE FORECAST TO DIMINISH WITHIN THE NEXT 12 HOURS AS THE SUBTROPICAL HIGH WEAKENS SOME. ALSO WITH RESPECT TO THE RIDGE...THE PRES GRADIENT BETWEEN IT AND LOW PRES OVER SRN CALIFORNIA AND NRN MEXICO IS ALLOWING FOR AN AREA OF N-NE 20 KT WITH SEAS TO 8 FT TO EXIST N OF 27N BETWEEN 123W-132W. SHIP "ZCDA9' AT 29N128W MOVING E IS REPORTING N WINDS OF 22 KT. THIS AREA WILL EXPAND TO N OF 28N BETWEEN 119W-124W IN 24 HRS...AND TO N OF 28N BETWEEN 120W-125W IN 48 HRS AT WHICH TIME THE WINDS BECOME NW-N AT 20 KT WITH SEAS TO 9 FT IN A NW SWELL. WITH HURRICANE JOVA APPROACHING THE MEXICAN COAST...THE PRES GRADIENT WILL TIGHTEN OVER THE GULF OF CALIFORNIA WHERE FRESH NW-N WINDS ARE EXPECTED TO BEGIN TONIGHT FROM 23N-30N AND PERSIST THROUGH EARLY THU...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 BROAD LOW PRES OVER CENTRAL AMERICA THAT EXTENDS WESTWARD TO ENCOMPASS IRWIN AND JOVA. SHIP "DCRN2" AT 11N89 IS REPORTING SW WINDS OF 30 KT. AN ASCAT PASS FROM NEAR 1200 UTC THIS MORNING CONFIRMED THE EASTERN FRINGE OF THE SOUTHWESTERLY MONSOONAL FLOW N OF 2N AND TO THE SSE OF THE LOW NEAR 11N95W. 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 EASTERN WATERS WILL MAINTAIN LOW LEVEL CONFLUENCE AND CONTINUE TO PRODUCE ACTIVE CONVECTION NEAR THE MONSOON TROUGH. SEAS REMAINED CHURNED UP OVER THE CENTRAL PACIFIC PORTION WHERE THE COMBINATION OF A NW SWELL COMPONENT 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 STORM IRWIN. A NEW PULSE OF NW SWELL IS CURRENTLY PROPAGATING INTO THE FORECAST AREA 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 IS FORECAST TO MOVE INTO SOUTHERN WATERS TUE AND WILL RAISE SIGNIFICANT WAVE HEIGHTS TO 8 TO 12 FT IN 24 HRS...THE SUBSIDE SOME BY 48 HRS. $$ AGUIRRE