000 AXPZ20 KNHC 271005 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE SEP 27 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 0930 UTC. ...SPECIAL FEATURE... HURRICANE HILARY WAS LOCATED NEAR 16.6N 115.7W AT 0900 UTC MOVING W OR 265 DEG AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 961 MB. MAXIMUM SUSTAINED WINDS ARE 100 KT WITH GUSTS TO 125 KT. HILARY APPEARS TO HAVE PEAKED AND IS FORECAST TO SLOWLY WEAKEN OVER THE NEXT SEVERAL DAYS AS IT MAKES A SHARP TURN TO THE N. NUMEROUS STRONG CONVECTION IS LOCATED WITHIN 90 NM OF CENTER. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS LOCATED ELSEWHERE WITHIN 120 NM OF CENTER. SWELLS GENERATED BY HILARY ARE AFFECTING THE SOUTHERN HALF OF BAJA CALIFORNIA AND THE GULF OF CALIFORNIA S OF 25N...CAUSING HIGH SURF AND LIFE-THREATENING RIP CURRENT CONDITIONS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM EXTREME SW CARIBBEAN W ACROSS CENTRAL AMERICA AND ENTERS THE EPAC NEAR 11N86W TO 11.5N97W TO 10N103W WHERE IT TERMINATES...THEN RESUMES SW OF HURRICANE HILARY FROM 11N116W TO LOW PRES 10.5N128W 1010 MB TO 10N136W TO 09N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN A 60 NM RADIUS OF 10N128W. ...DISCUSSION... A WELL-DEFINED MIDDLE/UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED AT 28N129W AND IS FORECAST TO DRIFT SLOWLY E OVER THE NEXT COUPLE OF DAYS. MOVING DOWNSTREAM A MIDDLE/UPPER LEVEL TROUGH HAS ITS AXIS ORIENTED NE TO SW FROM S CENTRAL ARIZONA TO NEAR 25N114W. A SHARP UPPER LEVEL RIDGE SEPARATES THE TWO FEATURES MENTIONED ABOVE. BROAD RIDGING ALOFT COVERS A LARGE AREA FROM 08N TO 22N E OF ABOUT 135W...WITH HILARY PRESENTLY TRAPPED IN BETWEEN TWO UPPER ANTICYCLONES...ONE CENTERED OVER EXTREME SE MEXICO AND THE SECOND NEAR 17N127W. AT LOW LEVELS A 1021 MB SURFACE HIGH WAS CENTERED NEAR 29N131W WITH RIDGE EXTENDING E-SE TO S PORTIONS OF BAJA CALIFORNIAN NEAR 26N113W. THE PRES GRADIENT BETWEEN THE HIGH AND NW MEXICO WAS PRODUCING A NARROW ZONE OF NWLY WINDS TO 20 KT ALONG THE W COAST OF BAJA OUT TO 150 NM N OF 25N...WHILE NLY WINDS 15 TO 20 KT EXTENDED OUT TO NEAR 122W. THE PRES GRADIENT WAS ALSO INFLUENCING FAR NW PORTIONS OF HILARY...WHERE N TO NE WINDS 20 TO 25 KT EXTENDED OUTWARD TO 480 NM IN THE NW QUADRANT. TO THE S OF THE HIGH...PRES NE TRADEWINDS NEAR 20 KT WERE OCCURRING FROM 11N TO 20N W OF 126W...WITH SEAS TO 8 FT. THE HIGH WILL WEAKEN OVER THE NEXT FEW DAYS AS A SERIES OF WEAKENING COLD FRONTS MOVE TO NEAR THE NW CORNER OF THE AREA AND STALL. THIS COMBINED WITH THE BEGINNING OF A NORTHWARD MOTION OF HILARY WILL WEAKEN THE PRES GRADIENT AND WINDS ALONG THE BAJA PENINSULA...AND ALSO LIMIT FRESH NE TRADE WINDS TO JUST N OF THE ITCZ. A 1010 MB LOW PRES CENTER EMBEDDED WITHIN THE MONSOON TROUGH WAS NEAR 10.5N128W AND DRIFTING WWD. NUMEROUS MODERATE TO STRONG CONVECTION WAS OCCURRING WITHIN 120 NM NE AND 210 NM SW OF THIS LOW...WITH WINDS 20 TO 25 KT WITHIN 150 NM OF THE LOW. THIS FEATURE WILL DRIFT W THROUGH 24-36 HOURS BEFORE STALLING AND THEN BEGINNING TO DRIFT NE IN THE WAKE OF HILARY. OTHERWISE...LIGHT TO MODERATE MONSOONAL S TO SWLY WINDS PREVAIL S OF THE MONSOON TROUGH ACROSS THE AREA THIS MORNING. SEAS ARE DOMINATED BY MERGING SW CROSS EQUATORIAL SWELL AND NW SWELL...AND ARE VERY CONFUSED IN A BROAD MIX OF SWELL WITHIN 300 NM OF HILARY. $$ STRIPLING