000 AXPZ20 KNHC 102155 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURES... HURRICANE JOVA CENTERED NEAR 16.8N 106.2W AT 10/2100 UTC MOVING NE OR 050 DEG AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 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 STRONG CONVECTION IS NOTED WITHIN 75 NM OF THE CENTER IN THE NE QUADRANT ...WHILE SCATTERED STRONG CONVECTION IS ELSEWHERE WITHIN 90 NM OF THE CENTER. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS IDENTIFIED IN OUTER RAIN BAND N AND N E OF THE CENTER WITHIN 45 NM OF LINE FROM 17.5N103W TO 19N106W TO 18N107W. AN EYE DIAMETER OF 15 NM IS OBSERVED. LATEST NHC ADVISORY FORECASTS JOVA TO INTENSIFY SLIGHTLY TONIGHT AS IT CONTINUES ON A NE MOTION AS IT APPROACHES CENTRAL MEXICO...WITH LANDFALL IN STORE FOR LATE TUE NIGHT. LARGE AND DANGEROUS WAVES ASSOCIATED WITH JOVA WILL PROGRESSIVELY INCREASE THROUGH TUE AS JOVA NEARS THE COAST. 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 14.9N 116.9W AT 10/2100 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 A MINIMAL TROPICAL STORM BEING INFLICTED BY UPPER ELY SHEAR. ITS IS ALSO BEING AFFECTED BY STABLE AIR FILTERING INTO IT FROM THE W HAMPERING IT FROM INTENSIFYING. BASED ON THIS IRWIN IS FORECAST TO WEAKEN INTO A DEPRESSION OVERNIGHT TONIGHT...AND REMAIN AT THAT STATUS THROUGH THE NEXT 48 HRS AS REACHES TO NEAR 16N110W PER THE LATEST NHC FORECAST. LATEST SATELLITE IMAGERY SHOWED SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 60-90W OF THE CENTER IN THE SW SEMICIRCLE. THERE IS SOME CHANCE IRWIN COULD DEGENERATE FURTHER DURING ITS FORECAST PERIOD IF THE ELY SHEAR OVER IT INCREASES. A 1006 MB LOW LOCATED NEAR 12N95W IS DRIFTING N. THE CONVECTION ASSOCIATED WITH THE SYSTEM REMAINS DISPLACED TO THE W AS THE LOW REMAINS UNDER NELY SHEAR. THE CONVECTION IS OF THE SCATTERED STRONG TYPE WITHIN 140 NM IN THE SW QUADRANT. SCATTERED STRONG CONVECTION NW OF THE LOW WITHIN 45 NM OF 13N97W. WINDS ARE 20-25 KT WITHIN 120 NM IN THE NW QUADRANT OF THE LOW WITH SEAS OF 8-10 FT. THESE WINDS ARE EXPECTED TO INCREASE TO 30 KT WITHIN 60-75 NM OF THE LOW BY 24 HRS...AND INTO 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 SOME 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 13N88W TO 1006 MB LOW PRES NEAR 12N95W WHERE IT ENDS DUE TO THE CYCLONIC CIRCULATIONS AROUND HURRICANE JOVA AND TROPICAL STORM IRWIN. IT THEN RESUMES FROM 13N120W TO 10N130W TO 9N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS WITHIN 120-180 NM NE OF A LINE FROM 11N90W TO 5N80W. SCATTERED MODERATE TO STRONG CONVECTION IS SEEN FROM 10N-14N BETWEEN 95W-98W. SCATTERED MODERATE CONVECTION IS FROM 7N-14N BETWEEN 98W-102W. ...DISCUSSION... A LARGE UPPER LEVEL ANTICYCLONE IS NW OF THE DISCUSSION AREA AT ROUGHLY 33N137W WITH A RIDGE E TO SRN CALIFORNIA. A DEEP LAYER TROUGH EXTENDS FROM INTERMOUNTAIN U.S. SW TO ACROSS NRN BAJA CALIFORNIA AND TO A COL REGION AT 26N130W. SW OF THE COL REGION...A MID/UPPER LEVEL TROUGH EXTENDS SOUTHWESTWARD TO A MID/UPPER LEVEL CYCLONIC CIRCULATION W OF 140W AT 20N146W. AT THE SURFACE...A 1022 MB SUBTROPICAL HIGH IS CENTERED NEAR 30N140W WITH A RIDGE ESE TO NEAR 25N123W. SATELLITE WATER VAPOR IMAGERY SHOWS A SWATH OF MODERATE SUBSIDENCE CREATING A RATHER STABLE ATMOSPHERIC ENVIRONMENT REFLECTED AT THE SURFACE AS BROKEN STRATOCUMULUS CLOUDS MOVING SWD TO THE N OF 17N W OF 125W...AND SOUTHEASTWARD INTO THE W SIDE OF TROPICAL STORM IRWIN. 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-20N W OF 135W WITH 8 FT SEAS. THESE TRADE WINDS ARE FORECAST TO DIMINISH WITHIN THE NEXT 12-18 HOURS AS THE SUBTROPICAL HIGH WEAKENS SOME WHILE SHIFTING W. 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 WINDS WITH SEAS TO 8 FT TO EXIST N OF 28N BETWEEN 120W-126W. SHIP "ZCDA9' AT 29N126W MOVING E IS REPORTING N WINDS OF 25 KT. THIS AREA WILL EXPAND TO N OF 24N BETWEEN 119W-126W IN 24 HRS...THEN DIMINISH TO LESS THAN 20 KT BY 48 HRS AT WHICH TIME SEAS OF 8-10 FT IN A NW SWELL SHOULD BE EVIDENT N OF 20N AND W OF 120W. 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-26N AND THEN BE CONFINED TO THE FAR NRN GULF BY WED EVENING. FRESH SOUTHWESTERLY MONSOON FLOW DOMINATES THE AREA S OF THE THREE SPECIAL FEATURES NOTED ABOVE. THE PRES GRADIENT IS STRONGEST BETWEEN THE RIDGE PORTION OVER THE EASTERN SOUTH PACIFIC AND BROAD LOW PRES THAT COVERS CENTRAL AMERICA AND THAT EXTENDS WESTWARD TO ENCOMPASS TROPICAL CYCLONES IRWIN AND JOVA. A SHIP EARLIER WITH CALL SIGN "DCRN2" AT 11N89 REPORTED SW WINDS OF 30 KT. AN ASCAT PASS FROM 1532 UTC THIS MORNING CONFIRMED THE EASTERN FRINGE OF THE SOUTHWESTERLY MONSOONAL FLOW N OF 2N AND TO THE SSE OF THE LOW NEAR 12N95W. THESE SW WINDS WILL MAINTAIN LOW LEVEL CONFLUENCE AND CONTINUE TO PRODUCE ACTIVE CONVECTION NEAR THE MONSOON TROUGH THROUGH THE NEXT 48 HRS. SEAS REMAINED CHURNED UP OVER THE CENTRAL PACIFIC PORTION WHERE THE COMBINATION OF A NW SWELL COMPONENT FROM THE FRONTAL SYSTEMS N OF THE DISCUSSION AREA...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. SEAS OF 8-12 FT ARE WITHIN THE AREA OF SW-W 20-25 KT WINDS FROM 4N-12N BETWEEN 80W-100W. THIS AREA WILL SHRINK SOME OVER THE 24-48 HRS...HOWEVER SEAS OF 8-12 FT IN A SW SWELL WILL CONTINUE. $$ AGUIRRE