000 AXPZ20 KNHC 232133 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI SEP 23 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 FEATURE... HURRICANE HILARY WAS NEAR 16.3N 103.1W AT 2100 UTC MOVING W OR 280 DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 942 MB. MAXIMUM SUSTAINED WINDS ARE 125 KT WITH GUSTS TO 150 KT MAKING HILARY A CATEGORY FOUR HURRICANE ON THE SAFFIR-SIMPSON SCALE. SATELLITE PRESENTATION CONTINUES TO BE RATHER IMPRESSIVE AS A SMALL WARM EYE OF ABOUT 15 NM IS EVIDENT THIS AFTERNOON. THE VERY DEEP CONVECTION ASSOCIATED WITH HILARY CONSISTS OF NUMEROUS STRONG CONVECTION WITHIN 90 NM OF THE CENTER IN THE E SEMICIRCLE AND 50 NM IN THE W SEMICIRCLE. A VERY LARGE CLUSTER OF NUMEROUS STRONG CONVECTION IS TO THE W OF HILARY N OF 15N AND BETWEEN 104W AND 106W. HILARY REMAINS UNDER A BROAD UPPER LEVEL ANTICYCLONE ...OVER VERY WARM SEA SURFACE TEMPERATURES...AND IN A LOW VERTICAL WIND SHEAR ENVIRONMENT. ALL OF THESE FACTORS ARE CONDUCIVE FOR IT TO MAINTAIN ITS CURRENT INTENSITY. HILARY IS THE FOURTH MAJOR HURRICANE OF THE 2011 EAST PACIFIC HURRICANE SEASON. HILARY IS EXPECTED TO MAINTAIN A WNW MOTION THROUGH THE NEXT COUPLE OF DAYS BEFORE IT ENCOUNTERS GRADUALLY DECREASING SSTS...LESS UNSTABLE AIR...AND INCREASING VERTICAL SHEAR SHOULD LIKELY RESULT IN A WEAKENING TREND. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 10N84W TO 5N90W...THEN RESUMES FROM 16N112W TO 12N123W TO 11N132W TO 10N140W. SCATTERED STRONG CONVECTION EXISTS N OF 5N E OF 82W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 110W-113W AND 124W-127W. SCATTERED MODERATE CONVECTION IS N OF THE MONSOON TROUGH WITHIN 30 NM OF 14N125W. ...DISCUSSION... A NARROW UPPER LEVEL TROUGH EXTENDS FROM AN UPPER CYCLONE OFF THE SW COAST OF CALIFORNIA NEAR 34N123W TO A SECOND UPPER CYCLONE NEAR 24N139W WITH A TROUGH SSW TO 11N141W. BROAD MID/UPPER LEVEL RIDGING COVERS THE REMAINDER OF THE AREA ANCHORED BY AN ELONGATED ANTICYCLONE EXTENDING FROM HURRICANE HILARY EASTWARD TO A SMALL ANTICYCLONE OVER THE NW YUCATAN PENINSULA AND EXTENDING W-SW TO 13N136W. WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE OVER THE AREA N OF 20N. S OF 20N AMPLE DEEP MOISTURE IS NOTED ALONG AND WITHIN 480 NM S OF THE MONSOON TROUGH. AT THE SURFACE...A 1022 MB HIGH IS ANALYZED NEAR 31N132W WITH A RIDGE SE TO NEAR 22N118W. HIGH PRESSURE COVERS THE AREA N OF 15N W OF 118W. SPORADIC LIGHT TO MODERATE TRADEWINDS CONTINUE N OF THE MONSOON TROUGH AND W OF 120W. AN ASCAT PASS FROM AROUND 1800 UTC THIS AFTERNOON SHOWED SE-S WINDS OF 15-20 KT S OF THE MONSOON TROUGH W OF ABOUT 119W. THESE WINDS ARE EXPECTED TO CHANGE LITTLE OVER THE NEXT 48 HOURS...HOWEVER CROSS EQUATORIAL SWELLS PRODUCING SEAS OF UP TO 8 FT ARE EXPECTED TO MOVE INTO THE WATERS S OF 11N BETWEEN 119W -130W...WHILE SIMILAR SWELLS E OF 119W TO NEAR 104W WILL MERGE WITH THOSE PROPAGATING AWAY FROM HILARY. OTHER SLY SWELLS TO 8 FT ARE FORECAST TO MOVE FROM THE SOUTHERN HEMISPHERE NORTHWARD INTO THE AREA REACHING TO NEAR 5N AND BETWEEN 96W-104W IN 48 HOURS. A VERY PROGRESSIVE NORTHERN STREAM NW OF THE AREA CHARACTERIZED BY BROAD DEEP LAYER TROUGHING MOVING RAPIDLY EASTWARD WILL DRIVE A COLD FRONT INTO THE DISCUSSION AREA IN 48W HOURS AT WHICH TIME THE FRONT WILL REACH FROM 30N135W TO 28N140W IN 48 HOURS. AHEAD OF THE FRONT...SW 20 KT WINDS ARE EXPECTED N OF 28N W OF 135W ...WITH NE 20 KT BEHIND THE FRONT. THE DEEP LAYER TROUGH WILL MOVE INLAND OVER THE PACIFIC NW AND NORTHERN CALIFORNIA REGIONS SUN EVENING LEAVING BEHIND A TRAILING TROUGH OVER THE FAR NW PORTION. THE TROUGH IS FORECAST TO EVOLVE INTO AN UPPER CYCLONE NEAR 26N131W BY LATE SUN NIGHT. ELSEWHERE WITH REGARDS TO MARINE IMPACTS...LARGE SWELLS RADIATING OUTWARD FROM HILARY FARE FORECAST BY WAVEWATCH MODEL GUIDANCE TO SPREAD INTO THE SOUTHERN SECTOR OF THE GULF OF CALIFORNIA THIS WEEKEND RAISING SEAS TO POSSIBLY AS HIGH AS 9 OR 10 FT. $$ AGUIRRE 000 AXPZ20 KNHC 232133 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI SEP 23 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 2115 UTC. ...SPECIAL FEATURE... HURRICANE HILARY WAS NEAR 16.3N 103.1W AT 2100 UTC MOVING W OR 280 DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 942 MB. MAXIMUM SUSTAINED WINDS ARE 125 KT WITH GUSTS TO 150 KT MAKING HILARY A CATEGORY FOUR HURRICANE ON THE SAFFIR-SIMPSON SCALE. SATELLITE PRESENTATION CONTINUES TO BE RATHER IMPRESSIVE AS A SMALL WARM EYE OF ABOUT 15 NM IS EVIDENT THIS AFTERNOON. THE VERY DEEP CONVECTION ASSOCIATED WITH HILARY CONSISTS OF NUMEROUS STRONG CONVECTION WITHIN 90 NM OF THE CENTER IN THE E SEMICIRCLE AND 50 NM IN THE W SEMICIRCLE. A VERY LARGE CLUSTER OF NUMEROUS STRONG CONVECTION IS TO THE W OF HILARY N OF 15N AND BETWEEN 104W AND 106W. HILARY REMAINS UNDER A BROAD UPPER LEVEL ANTICYCLONE ...OVER VERY WARM SEA SURFACE TEMPERATURES...AND IN A LOW VERTICAL WIND SHEAR ENVIRONMENT. ALL OF THESE FACTORS ARE CONDUCIVE FOR IT TO MAINTAIN ITS CURRENT INTENSITY. HILARY IS THE FOURTH MAJOR HURRICANE OF THE 2011 EAST PACIFIC HURRICANE SEASON. HILARY IS EXPECTED TO MAINTAIN A WNW MOTION THROUGH THE NEXT COUPLE OF DAYS BEFORE IT ENCOUNTERS GRADUALLY DECREASING SSTS...LESS UNSTABLE AIR...AND INCREASING VERTICAL SHEAR SHOULD LIKELY RESULT IN A WEAKENING TREND. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 10N84W TO 5N90W...THEN RESUMES FROM 16N112W TO 12N123W TO 11N132W TO 10N140W. SCATTERED STRONG CONVECTION EXISTS N OF 5N E OF 82W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 110W-113W AND 124W-127W. SCATTERED MODERATE CONVECTION IS N OF THE MONSOON TROUGH WITHIN 30 NM OF 14N125W. ...DISCUSSION... A NARROW UPPER LEVEL TROUGH EXTENDS FROM AN UPPER CYCLONE OFF THE SW COAST OF CALIFORNIA NEAR 34N123W TO A SECOND UPPER CYCLONE NEAR 24N139W WITH A TROUGH SSW TO 11N141W. BROAD MID/UPPER LEVEL RIDGING COVERS THE REMAINDER OF THE AREA ANCHORED BY AN ELONGATED ANTICYCLONE EXTENDING FROM HURRICANE HILARY EASTWARD TO A SMALL ANTICYCLONE OVER THE NW YUCATAN PENINSULA AND EXTENDING W-SW TO 13N136W. WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE OVER THE AREA N OF 20N. S OF 20N AMPLE DEEP MOISTURE IS NOTED ALONG AND WITHIN 480 NM S OF THE MONSOON TROUGH. AT THE SURFACE...A 1022 MB HIGH IS ANALYZED NEAR 31N132W WITH A RIDGE SE TO NEAR 22N118W. HIGH PRESSURE COVERS THE AREA N OF 15N W OF 118W. SPORADIC LIGHT TO MODERATE TRADEWINDS CONTINUE N OF THE MONSOON TROUGH AND W OF 120W. AN ASCAT PASS FROM AROUND 1800 UTC THIS AFTERNOON SHOWED SE-S WINDS OF 15-20 KT S OF THE MONSOON TROUGH W OF ABOUT 119W. THESE WINDS ARE EXPECTED TO CHANGE LITTLE OVER THE NEXT 48 HOURS...HOWEVER CROSS EQUATORIAL SWELLS PRODUCING SEAS OF UP TO 8 FT ARE EXPECTED TO MOVE INTO THE WATERS S OF 11N BETWEEN 119W -130W...WHILE SIMILAR SWELLS E OF 119W TO NEAR 104W WILL MERGE WITH THOSE PROPAGATING AWAY FROM HILARY. OTHER SLY SWELLS TO 8 FT ARE FORECAST TO MOVE FROM THE SOUTHERN HEMISPHERE NORTHWARD INTO THE AREA REACHING TO NEAR 5N AND BETWEEN 96W-104W IN 48 HOURS. A VERY PROGRESSIVE NORTHERN STREAM NW OF THE AREA CHARACTERIZED BY BROAD DEEP LAYER TROUGHING MOVING RAPIDLY EASTWARD WILL DRIVE A COLD FRONT INTO THE DISCUSSION AREA IN 48W HOURS AT WHICH TIME THE FRONT WILL REACH FROM 30N135W TO 28N140W IN 48 HOURS. AHEAD OF THE FRONT...SW 20 KT WINDS ARE EXPECTED N OF 28N W OF 135W ...WITH NE 20 KT BEHIND THE FRONT. THE DEEP LAYER TROUGH WILL MOVE INLAND OVER THE PACIFIC NW AND NORTHERN CALIFORNIA REGIONS SUN EVENING LEAVING BEHIND A TRAILING TROUGH OVER THE FAR NW PORTION. THE TROUGH IS FORECAST TO EVOLVE INTO AN UPPER CYCLONE NEAR 26N131W BY LATE SUN NIGHT. ELSEWHERE WITH REGARDS TO MARINE IMPACTS...LARGE SWELLS RADIATING OUTWARD FROM HILARY FARE FORECAST BY WAVEWATCH MODEL GUIDANCE TO SPREAD INTO THE SOUTHERN SECTOR OF THE GULF OF CALIFORNIA THIS WEEKEND RAISING SEAS TO POSSIBLY AS HIGH AS 9 OR 10 FT. $$ AGUIRRE