000
AXPZ20 KNHC 291544
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED AUG 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ILEANA IS CENTERED NEAR 18.2N 112.6W AT 29/1500 
UTC OR ABOUT 320 NM SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA 
MOVING NW AT 09 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 
MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. 
SCATTERED TO NUMEROUS MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 150 NM OF CENTER. SCATTERED MODERATE CONVECTION IS 
ELSEWHERE FROM 14N TO 20N BETWEEN 108W AND 117W. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC 
FOR MORE DETAILS.

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

THE MONSOON TROUGH IS ALONG 11N86W TO 10N94W TO 12N101W THEN 
RESUMES NEAR 14N113W TO 10N126W TO 11N135W. SCATTERED MODERATE 
CONVECTION IS FROM 03N TO 07N BETWEEN 76W AND 81W...AND FROM 07N 
TO 15N BETWEEN 97W AND 104W. ISOLATED MODERATE CONVECTION IS 
ELSEWHERE FROM 05N TO 15N BETWEEN 82W AND 98W.

...DISCUSSION...

A 1030 MB SURFACE HIGH PRESSURE LOCATED WELL NW OF THE FORECAST 
AREA NEAR 43N153W EXTENDS A RIDGE SOUTHEASTWARD THROUGH 32N138W 
TO NEAR 22N122W. HIGH PRESSURE COVERS THE AREA N OF 15N AND W OF 
120W. LIGHT TO MODERATE NE WINDS ARE NOTED UNDER THE INFLUENCE 
OF THIS SYSTEM. A SMALL AREA OF ENHANCED NE WINDS IS NOTED ON 
THE SOUTHERN PERIPHERY OF THE RIDGE NEAR 14N139W. THESE WINDS 
WERE CAPTURED BY AN OVERNIGHT ASCAT PASS AROUND 29/0619 UTC.

AN EARLIER ASCAT PASS AROUND 29/0436 UTC REVEALED A SWATH OF SW 
20-25 KT MONSOON WINDS IN THE VICINITY OF 10N BETWEEN 110W AND 
120W...WHICH IS PRIMARILY A LONG-FETCH AREA OF S TO SW WINDS 
FEEDING INTO TROPICAL STORM ILEANA TO THE NORTH.

LOOKING AHEAD IN THE NEXT 24 TO 48 HOURS...MOST OF THE GLOBAL 
MODELS HINT AT A WEAK 1009 MB SURFACE LOW DEVELOPING IN THE 
VICINITY OF 10N95W BY 30/1200 UTC. FOR THE HIGH SEAS FORECAST... 
A BLEND OF THE GFS...ECMWF...UKMET...AND NOGAPS WAS USED FOR 
POSITIONING AS S TO SW MONSOONAL FLOW SETS UP AND INCREASES OVER 
THE SOUTHERN AND EASTERN SEMICIRCLES OF THE LOW WITH SEAS 
BUILDING TO 10 FT BY THE END OF THE FORECAST PERIOD.

CROSS-EQUATORIAL SW SWELLS WITH IMPRESSIVE 18-20 SECOND PERIODS  
ARE CURRENTLY SPREADING ACROSS THE SOUTHERN WATERS W OF 100W. 
THIS SWELL EVENT WILL RAISE SEAS TO 9 FT MAINLY S OF 05N BETWEEN 
111W AND 132W TODAY INTO TONIGHT...AND S OF A LINE FROM 03N93W 
TO 11N110W TO 10N122W TO 07N130W BY FRIDAY MORNING. THESE SWELLS 
MAY BEGIN TO IMPACT THE COASTAL REGIONS OF MEXICO AND CENTRAL 
AMERICA LATE THURSDAY.

$$
HUFFMAN