000 AXPZ20 KNHC 090925 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN OCT 09 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 0745 UTC. ...SPECIAL FEATURES... HURRICANE JOVA CENTERED NEAR 16.0N 109.2W AT 09/0900 UTC MOVING E OR 090 DEG AT 5 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 150 NM SE SEMICIRCLE AND 90 NM NW SEMICIRCLE OF CENTER. SCATTERED MODERATE CONVECTION IS FOUND ELSEWHERE WITHIN 240 NM S QUADRANT AND 300 NM W QUADRANT. JOVA IS EXPECTED TO CONTINUE MOVING E-NE TOWARD W CENTRAL MEXICO WITH THE CURRENT FORECAST TAKING JOVA INLAND BY EARLY WED. ADDITIONAL STRENGTHENING IS FORECAST UNTIL LANDFALL WITH THE CURRENT FORECAST HAVING JOVA REACHING MAJOR HURRICANE STRENGTH JUST PRIOR TO LANDFALL. TROPICAL STORM IRWIN CENTERED NEAR 14.9N 120.1W AT 09/0900 UTC MOVING NE OR 055 DEG AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. IRWIN CONTINUES TO LIMITED DEEP CONVECTION ASSOCIATED WITH IT...WITH ISOLATED TO SCATTERED MODERATE FOUND ONLY WITHIN 90 NM SE QUADRANT AND 210 NM SW QUADRANT. IRWIN IS EXPECTED TO GRADUALLY MOVE E-NE IN THE GENERAL DIRECTION OF W CENTRAL MEXICO THROUGH 120 HOURS. IRWIN IS FORECAST TO FLUCTUATE LITTLE IN INTENSITY THROUGH 72 HOURS WITH SLIGHTLY STRENGTHENING POSSIBLE THEREAFTER. 1007 MB LOW PRES IS LOCATED NEAR 11N96W. NUMEROUS MODERATE TO STRONG CONVECTION IS DISPLACED BETWEEN 70 NM AND 210 NM OF THE NW QUADRANT OF THIS LOW. THE 0318 UTC ASCAT PASS CONTINUES TO SHOW A BROAD BUT CLOSED LOW LEVEL CIRCULATION WITH THE STRONGEST WINDS DISPLACED S AND W OF THE CENTER. THIS LOW IS FORECAST TO MOVE E-NE AROUND 5 KT OVER THE NEW FEW DAYS. THERE IS A HIGH CHANCE THAT IT COULD BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS IS ANALYZED FROM 11N85W TO 12N90W TO LOW PRES NEAR 11N96W THEN CONTINUES FROM 12N127W TO 08N138W. THE ITCZ AXIS IS ANALYZED FROM 08N138W TO 08N140W. SCATTERED MODERATE TO STRONG CONVECTION LIES WITHIN 120 NM EITHER SIDE OF AXIS E OF 91W WITH NUMEROUS MODERATE TO STRONG CONVECTION FOUND ELSEWHERE N OF 06N BETWEEN 81W AND 89W. ...DISCUSSION... THE 1028 MB SUBTROPICAL HIGH PRES IS CENTERED N OF THE AREA NEAR 32N139W WITH A RIDGE AXIS EXTENDING SE TO NEAR 23N110W. THE PRES GRADIENT BETWEEN THIS RIDGE AND LOWER PRES ASSOCIATED WITH TROPICAL STORM IRWIN AND HURRICANE JOVA CONTINUES TO PRODUCE FRESH NE TRADES FROM 18N TO 25N W OF 120W. THESE TRADES WILL SHRINK TO W OF 135W OVER THE NEXT 24 HOURS AS THE SUBTROPICAL HIGH MOVES SW AND IRWIN AND JOVA MOVE E. THE PRES GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER INLAND MEXICO IS MAINTAINING FRESH NW TO N WINDS OVER THE GULF OF CALIFORNIA FROM 27N TO 30N WHICH WILL DIMINISH LATER TODAY AS THE HIGH RETREATS. ON MON...THE EASTWARD MOVEMENT OF IRWIN WILL ERODE THE SOUTHERN EDGE OF THE RIDGE AND SHIFT THE STRONGEST PRES GRADIENT TO OVER N CENTRAL WATERS WHERE FRESH N WINDS WILL DEVELOP. BY LATE MON...THE SUBTROPICAL HIGH WILL RETROGRADE INTO NW FORECAST WATERS...SHIFTING THE AREA OF TRADES BACK TO THE E. 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 MUCH OF CENTRAL AMERICA AND COLOMBIA EXTENDING W TO ENCOMPASS IRWIN AND JOVA. OVER EASTERN WATERS...WINDS ARE EXPECTED TO INCREASE TO STRONG AND 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. NW SWELL IS CONTINUING TO PROPAGATE THROUGH THE NORTHERN FORECAST WATERS AND IS MERGING WITH CROSS-EQUATORIAL SW SWELL OVER CENTRAL WATERS INCLUDING THE AREAS NEAR JOVA AND IRWIN. COMBINED SEAS ARE AS HIGH AS 12 FT IN THIS AREA WHERE MERGING SWELL COMBINED WITH FRESHLY GENERATED WIND WAVES IS CREATING A VERY CONFUSED AND CHAOTIC SEA STATE THAT IS EXPECTED TO PERSIST TODAY BEFORE THE SW SWELL BECOMES THE DOMINANT SWELL COMPONENT. A NEW PULSE OF NW SWELL WILL PROPAGATE INTO THE FORECAST AREA SUN NIGHT INTO MON. THIS SWELL WILL HELP KEEP SEAS TO 9 FT OVER N CENTRAL WATERS WHERE THE AFOREMENTIONED FRESH N WINDS WILL BE IN PLACE. $$ SCHAUER