000
AXPZ20 KNHC 262141
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON SEP 26 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 
2030 UTC.

...SPECIAL FEATURE...

HILARY REMAINS A POWERFUL HURRICANE. AT 2100 UTC...THE EYE OF 
HURRICANE HILARY WAS LOCATED ABOUT 115 NM SSE OF CLARION ISLAND  
NEAR 16.6N 114.0W MOVING W OR 265 DEG AT 9 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 949 MB. MAXIMUM SUSTAINED WINDS ARE NOW 115 
KT GUSTS TO 140 KT. MINOR FLUCTUATIONS IN INTENSITY ARE POSSIBLE 
DURING THE NEXT DAY OR SO...BUT THE OVERALL TREND IS FOR HILARY 
TO SLOWLY WEAKEN DURING THE NEXT 36-48 HOURS THEN TURN NORTH WED.

NUMEROUS STRONG CONVECTION WITHIN 60 NM OF CENTER. SCATTERED 
MODERATE CONVECTION 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 THE NORTHERN COSTA RICA COAST 
NEAR 10N85W TO 11N103W...THEN RESUMES W OF HURRICANE HILARY FROM 
14N117W TO 10N130W TO 10N135W. ITCZ AXIS EXTENDS FROM 10N135W TO 
10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 
NM OF 10N127W.

...DISCUSSION... 

HIGH PRES RIDGE EXTENDS SE FROM A 1021 MB HIGH CENTERED NEAR 
27N132W TO NEAR 24N116W. SCATTEROMETER DATA FROM 1700 UTC SHOWS 
THAT HURRICANE HILARY IS BEGINNING TO INTERACT WITH THIS RIDGE 
TO THE NW...AND WINDS ARE INCREASING IN THE NORTHWEST SEMICIRCLE 
AS A RESULT. AN AREA OF FRESH TO STRONG NNE WINDS HAS DEVELOPED 
FROM 18N TO 23N W OF 115W TO THE SWATH EDGE NEAR 118W. PRESSURE 
GRADIENT BETWEEN THE HIGH PRES AND A PERSISTENT TROUGH OVER 
WESTERN MEXICO IS ALSO SUPPORTING FRESH NW WINDS N OF 25N NEAR 
THE W COAST OF BAJA CALIFORNIA. LITTLE CHANGE IS EXPECTED IN THE 
GENERAL SYNOPTIC PATTERN THE NEXT 12-24 HOURS AS THE HIGH REMAINS
NEARLY STATIONARY. HOWEVER AFTER 24 HOURS THE HIGH WILL BEGIN TO 
RETREAT SLOWLY NW...ALLOWING WINDS TO DIMINISH ALONG THE BAJA.

A WEAK FRONT CROSSING THE AREA NEAR 30N140W WILL BECOME DIFFUSE 
THEN DISSIPATE BY TUE. MODERATE SW WINDS WITH SEAS BELOW 8 FT 
WILL CONTINUE THROUGH TUE...BUT INCREASE AGAIN TO 8 TO 10 FT TUE 
NIGHT AS A REINFORCING SURGE OF NW SWELL MOVES INTO NW PORTIONS. 
THE LONG-PERIOD NW SWELL WILL MERGE WITH MIXED SWELL GENERATED 
BY HILLARY ON WED...CREATING A LARGE AREA OF SEAS GREATER THAN 8 
FT...ROUGHLY BOUNDED BY N OF 10N AND W OF 105W.

CONVECTION ASSOCIATED WITH THE MONSOON TROUGH HAS DIMINISHED OVER
THE PAST 12-24 HOURS AND SHIFTED W OF 150W AS SHOWERS ALONG THE 
ITCZ BOUNDARY. LIGHT TO MODERATE S-SW WINDS ARE S OF THE MONSOON 
TROUGH EXCEPT FOR A SMALL AREA OF ENHANCED SOUTHERLY WINDS S OF 
07N BETWEEN 95W AND 103W. S SWELL FROM THE SOUTHERN HEMISPHERE IS
EVIDENT S OF 09N BETWEEN 90W AND 105W...PRODUCING SEAS TO 9 FT 
IN THE AREA OF ENHANCED SOUTHERLY FLOW MENTIONED ABOVE.

$$
MUNDELL