000
AXPZ20 KNHC 260300
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...SPECIAL FEATURE...

HILARY REMAINS A POWERFUL HURRICANE. AT 0300 UTC...IT IS 
CENTERED NEAR 16.9N 111.3W MOVING W OR 270 DEG AT 8 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 953 MB. MAXIMUM SUSTAINED 
WINDS ARE 110 KT GUSTS TO 135 KT. SOME FLUCTUATIONS IN INTENSITY 
ARE POSSIBLE DURING THE NEXT DAY OR SO...BUT THE OVERALL TREND 
SHOULD BE FOR HILARY TO SLOWLY WEAKEN DURING THE NEXT 48 HOURS. 
HILARY IS EXPECTED TO MOVE WEST TODAY...FOLLOWED BY A TURN 
TOWARD THE WEST-NORTHWEST ON TUESDAY. NUMEROUS STRONG CONVECTION 
IS WITHIN 45 NM OF CENTER. SCATTERED TO NUMEROUS MODERATE TO 
STRONG CONVECTION CAN BE FOUND ELSEWHERE FROM 14N TO 18N BETWEEN 
109W AND 112W. SWELLS GENERATED BY HILARY ARE STILL AFFECTING 
PORTIONS OF THE COAST OF SOUTHWESTERN MEXICO. THESE SWELLS ARE 
LIKELY CAUSING LIFE-THREATENING SURF AND 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 10N86W TO 09N100W THEN RESUMES 
W OF HURRICANE HILARY NEAR 14N113W TO 12N125W TO 12N140W. 
SCATTERED MODERATE TO ISOLATED STRONG FROM 06N TO 09N BETWEEN 
81W AND 92W. SIMILAR CONVECTION IS FROM 09N TO 11N BETWEEN 102W 
AND 104W. 

...DISCUSSION... 

HIGH PRES RIDGE EXTENDS SE FROM A 1020 MB HIGH CENTERED NEAR 
28N132W TO NEAR 22N113W. PRESSURE GRADIENT BETWEEN THE HIGH PRES 
AND A TROUGH OVER WESTERN MEXICO IS SUPPORTING FRESH NW WINDS N 
OF 23N E OF 118W TO THE W COAST OF BAJA CALIFORNIA. LITTLE 
CHANGE IS EXPECTED IN THE GENERAL SYNOPTIC PATTERN THE NEXT TWO 
DAYS AS THE HIGH REMAINS NEARLY STATIONARY. IN ADDITION...PRES 
GRADIENT BETWEEN THE AFOREMENTIONED HIGH PRES AND TROPICAL 
CYCLONE HILARY WILL RESULT IN AN AREA OF NLY WINDS UP TO 20 KT 
JUST TO THE WEST OF HILARY. 

A STATIONARY FRONT CROSSES NEAR 30N140W. SW WINDS OF 15 KT ARE 
IN THE FAR NW PORTION WITH SEAS TO 8 FT IN NW SWELL AFFECTING 
THE WATERS NW OF A LINE 30N135W TO 27N140W. SEAS ARE FORECAST TO 
SUBSIDE BELOW 8 FT LATE TODAY. A SMALL AREA OF MODERATE TO FRESH 
TRADE WINDS IS NOTED N OF THE MONSOON TROUGH TO 17N AND W OF 
122W. AN EARLIER WINDSAT PASS PROVIDED OBSERVATIONS OF THESE 
WIND SPEEDS. 

MODERATE TO ISOLATED STRONG CONVECTION IS NOTED S OF THE MONSOON 
TROUGH OVER PANAMA...COSTA RICA AND REGIONAL WATERS PARTICULARLY 
N OF 06N.  

LONG PERIOD NW SWELL IS MERGING WITH SW SWELL FROM THE SOUTHERN 
HEMISPHERE MAINLY S OF 05N.

$$
GR/DM