000
AXPZ20 KNHC 230306
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0145 UTC.

...SPECIAL FEATURE...

HURRICANE HILARY NEAR 16.0N 100.8W AT 23/0300 UTC MOVING WNW OR 
295 DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 948 MB. 
MAXIMUM SUSTAINED WINDS HAVE CONTINUED TO INCREASE TO 115 KT 
WITH GUSTS TO 140 KT MAKING HILARY A STRONG CATEGORY THREE 
HURRICANE ON THE SAFFIR-SIMPSON SCALE WITH A SMALL 10 NM EYE. 
NUMEROUS STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER IN ALL 
DIRECTIONS AND N OF 17N TO INLAND OVER S MEXICO BETWEEN 101W AND 
103W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ELSEWHERE 
N OF 14N BETWEEN 99W AND 103W. HILARY IS UNDER A LARGE 
ANTICYCLONE...AND OVER VERY WARM SEA SURFACE TEMPERATURES IN 
ADDITION TO BEING IN A LOW SHEAR ENVIRONMENT. HILARY IS THE 
FOURTH MAJOR HURRICANE OF 2011 EAST PACIFIC HURRICANE SEASON. 
SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS.
 
...ITCZ/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM 08N82W TO 07N89W AND THEN FROM 
16N103W TO 16N110W TO 12N120W TO 12N127W TO 09N133W. SCATTERED 
MODERATE ISOLATED STRONG WITHIN 90 NM EITHER SIDE OF A LINE FROM 
13N103W TO 11N109W AND FROM 10N116W TO 08N121W...AND WITHIN 75 
NM OF 17N BETWEEN 106W AND 109W.         

...DISCUSSION... 

A NARROW BUT SHARP UPPER LEVEL TROUGH EXTENDS FROM THE SW COAST 
OF CALIFORNIA AND ENTERS THE REGION THROUGH 32N124W ALONG 
28N133W TO AN UPPER LOW NEAR 24N141W. BROAD MID/UPPER LEVEL 
RIDGING COVERS THE REMAINDER OF THE AREA ANCHORED BY AN 
ELONGATED ANTICYCLONE EXTENDING FROM NEAR THE GULF OF 
TEHUANTEPEC ALONG 17N TO 105W ASSOCIATED WITH HURRICANE HILARY. 
SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG 
SUBSIDENCE OVER THE ENTIRE AREA WITH THE EXCEPTION OF THE 
MONSOON TROUGH AND NEAR HURRICANE HILARY WHERE THE UPPER LEVEL 
OUTFLOW IS CHANNELING MOISTURE IN THE FORM OF CIRRUS OUTFLOW 
FROM THE CYCLONE. AT THE SURFACE...A TROUGH EXTENDS FROM 13N140W 
TO 09N141W. SCATTERED MODERATE CONVECTION WAS NOTED FROM 09N TO 
12N W OF 137W TO THE TROUGH AXIS. A WEAK RIDGE EXTENDS FROM A 
1020 MB HIGH N OF THE DISCUSSION AREA SE THROUGH 32N133W TO NEAR 
20N119W. 

NW SWELLS WITH HEIGHTS TO 9 FT AND PERIODS OF 16-17 SECONDS 
CONTINUE TO PROPAGATE SE OVER THE NW PORTION OF THE MARINE AREA. 
THESE SWELLS ARE FORECAST TO EXTEND FROM SW BAJA CALIFORNIA TO 
THE EQUATOR AT 130W AND MERGE WITH ANOTHER LONGER PERIOD SWELL 
TRAIN ORIGINATING FROM THE SOUTH PACIFIC BY LATE FRI REACHING 
THE COAST OF MEXICO LATE SAT WITH PERIODS IN 18-19 SECONDS IN 
THE WAKE OF HURRICANE HILARY.    

$$
PAW