000
AXPZ20 KNHC 280331
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE AUG 28 2012

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 
0215 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION NINE-E UPGRADED TO TROPICAL STORM ILEANA AT 
28/0300 UTC. AT THIS TIME...IT IS CENTERED NEAR 15.5N 107.7W 
MOVING WNW OR 290 DEGREES AT 10 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WINDS 40 KT WITH GUSTS 
TO  50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADER MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. THIS STORM NAMED 
IS FORECAST TO REACH HURRICANE STRENGTH BY WED MORNING AS IT 
CONTINUES TO MOVE WEST-NORTHWESTWARD ON THE SOUTH SIDE OF A 
MID-LEVEL RIDGE CENTERED OVER THE SOUTHWESTERN UNITED STATES. 
NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED WITHIN 120 NM W 
SEMICIRCLE. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 12N 
TO 16N BETWEEN 105W AND 112W. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM 08N78W TO 13N96W THEN 
RESUMES WEST OF T.S. ILEANA NEAR 12N112W TO 11N121W TO 1010 MB 
LOW PRES NEAR 11N135W TO 08N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS NOTED N OF 07N E OF 84W INCLUDING THE GULF 
OF PANAMA AND FROM 10N TO 13N BETWEEN 96W AND 103W. SCATTERED 
MODERATE CONVECTION IS FROM 08N TO 13N BETWEEN 109W AND 120W.

...DISCUSSION...

WEAK 1019 MB HIGH PRESSURE CENTERED NEAR 31N129W EXTENDS A RIDGE 
SE OVER THE N WATERS TO NEAR 22N118W. MAINLY LIGHT TO MODERATE 
WINDS AREA NOTED UNDER THE INFLUENCE OF THIS RIDGE. A STATIONARY 
FRONTAL BOUNDARY IS APPROACHING THE FORECAST AREA FROM THE NORTH.
THIS FRONT WILL CLIP THE FAR NW PART OF THE REGION AND GRADUALLY 
DISSIPATE THIS TUE. WINDS IN ASSOCIATION WITH THE FRONT WILL 
REMAIN BELOW 20 KT WITH SEAS OF 4-5 FT. HIGH PRES IN THE WAKE OF 
THE FRONT WILL BUILD IN OVER THE NEXT COUPLE OF DAYS.   

ONCE AGAIN...SCATTEROMETER DATA PROVIDED OBSERVATIONS OF S TO SW 
WINDS OF 20 TO 25 KT S OF THE MONSOON TROUGH COVERING THE AREA 
FROM 06N TO 12N BETWEEN 102W AND 110W...AND FROM 06N TO 10N 
BETWEEN 110W AND 122W. THESE WINDS CONTINUE TO MAINTAIN SEAS IN 
THE 8 TO 10 FT RANGE. 

A 1010 MB LOW PRES REMAINS EMBEDDED IN THE MONSOON TROUGH NEAR 
11N135W. VISIBLE SATELLITE IMAGERY SHOWS A WELL DEFINED SWIRL OF 
LOW CLOUDS IN ASSOCIATION WITH THIS LOW FORECAST TO MOVE W OF 
THE AREA BY WED. MODERATE TO FRESH TRADE WINDS CAN BE FOUND FROM 
14N TO 20N W OF 120W.

CROSS-EQUATORIAL LONG PERIOD SW SWELL OF 20-22 SECONDS WILL 
IMPACT THE SOUTH WATERS BEGINNING THIS AFTERNOON RAISING SEAS TO 
9 FT MAINLY S OF 04N BETWEEN 110W AND 135W BY LATE WED.

$$
GR