000
AXPZ20 KNHC 280320
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED SEP 28 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 
0300 UTC.

...SPECIAL FEATURE...

HURRICANE HILARY WAS LOCATED NEAR 17.4N 117.7W AT 0300 UTC  
MOVING NW OR 310 DEG AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 968 MB. MAXIMUM SUSTAINED WINDS ARE 90 KT WITH GUSTS TO 110 
KT. A TURN TOWARD THE NORTH AND A DECREASE IN FORWARD SPEED ARE 
EXPECTED. WEAKENING IS FORECAST DURING THE NEXT 48 HOURS...AND 
HILARY IS EXPECTED TO WEAKEN TO A TROPICAL STORM ON FRIDAY. 
NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OF CENTER. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION ELSEWHERE WITHIN 120 NM NW 
OF CENTER. SWELLS GENERATED BY HILARY ARE AFFECTING THE WEST 
COAST OF BAJA CALIFORNIA AND THE SOUTHERN GULF OF CALIFORNIA... 
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 EXTENDS FROM 08N78W TO 10N82W TO 14N89W TO  
10N106W...THEN RESUMES SW OF HURRICANE HILARY FROM 13N120W TO 
LOW PRES 10N130W 1009 MB TO 09N140W. ISOLATED MODERATE 
CONVECTION IS FROM 07N TO 14N BETWEEN 93W AND 103W. SCATTERED 
MODERATE CONVECTION IS FROM 07N TO 12N BETWEEN 128W AND 132W.

...DISCUSSION... 

A 1028 MB HIGH IS NEAR 39N136W. A SURFACE RIDGE AXIS EXTENDS S 
TO 25N135W. S OF 30N...NE TRADE WINDS ARE LESS THAN 20 KT. NW 
SWELL IS N OF 20N W OF 130W. ELSEWHERE...HILARY IS GENERATING 
SWELL FROM ITS CENTER N OF 5N BETWEEN 100W AND 130W. A COLD 
FRONT WILL ENTER THE NW CORNER NEAR 30N140W IN 48 HOURS WITH 
CONVECTION. WINDS WILL BE 15 TO 20 KT N OF FRONT.  

A 1009 MB LOW PRES CENTER EMBEDDED WITHIN THE MONSOON TROUGH NEAR
10N130W IS DRIFTING NE AND GENERATING BURSTS OF ACTIVE 
CONVECTION AND FRESH WINDS WITHIN 120 NM OF THE CENTER.  LIGHT 
TO MODERATE S-SW WINDS WILL CONTINUE TO PREVAIL S OF THE MONSOON 
TROUGH ACROSS THE AREA THROUGH THU. MERGING SW CROSS-EQUATORIAL 
SWELL AND EXTRATROPICAL NW SWELL...ALONG WITH SWELL GENERATED BY 
HURRICANE HILARY...ARE CAUSING A CONFUSED SEA STATE...A BROAD 
MIX OF SWELL FROM 10N-25N BETWEEN 110 AND 125W.

$$
FORMOSA