000
AXPZ20 KNHC 050936
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI AUG 05 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURES...

HURRICANE EUGENE CENTERED NEAR 17.6N 122.3W AT 05/0900 UTC 
MOVING W-NW OR 285 DEGREES AT 11 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 987 MB. MAXIMUM SUSTAINED WINDS ARE 65 KT WITH GUSTS
TO 80 KT. EUGENE IS NOW A MINIMAL CATEGORY ONE HURRICANE ON THE 
SAFFIR-SIMPSON HURRICANE WIND SCALE. ADDITIONAL WEAKENING IS 
FORECAST DURING THE NEXT 24 HOURS...AND EUGENE SHOULD BECOME A 
TROPICAL STORM BY THIS AFTERNOON AS IT MOVES OVER COLDER WATER 
AND INTO A DRIER AND MORE STABLE ENVIRONMENT. EUGENE IS THEN 
FORECAST TO FURTHER WEAKEN TO A POST-TROPICAL/REMNANT LOW BY 48 
HOURS. SCATTERED MODERATE CONVECTION IS WITHIN 90-120 NM IN THE 
S SEMICIRCLE. SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO 
HEADERS TCPEP5/WTPZ35 KNHC AND FULL FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS TCMEP5/WTPZ25 FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 10N85W TO 08N97W TO 10N101W THEN 
RESUMES NEAR 14N124W TO 11N131W. THE INTERTROPICAL CONVERGENCE 
ZONE AXIS EXTENDS FROM 11N131W TO 09N140W. SCATTERED MODERATE 
CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE MONSOON TROUGH 
BETWEEN 95W AND 98W. SIMILAR CONVECTION IS WITHIN 90 NM S OF THE 
ITCZ BETWEEN 132W AND 137W.

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS OVER 27N115W WITH AN UPPER RIDGE 
EXTENDING SW TO A COL NEAR 15N140W. AN UPPER LEVEL TROUGH 
ATTEMPTING TO INTRUDE ON THE FAR NW PORTION WILL REMAIN BLOCKED 
BY THE ANTICYCLONE DURING THE NEXT 24-48 HOURS. VERY DRY AIR 
UNDER MODERATE TO STRONG SUBSIDENCE IS NOTED BY WATER VAPOR 
SATELLITE IMAGERY N OF 15N W OF 130W AN N OF 23N W OF THE BAJA 
CALIFORNIA PENINSULA. OTHERWISE...NE-E WINDS DOMINATE THE 
REMAINDER OF THE E PACIFIC.

AT THE SURFACE...1031 MB HIGH PRES CENTERED NW OF THE AREA NEAR 
38N149W EXTENDS A RIDGE OVER THE NORTHERN FORECAST WATERS N OF 
22N. THIS RIDGE IS HELPING TO STEER EUGENE OFF TO THE W-NW. THE 
PRES GRADIENT BETWEEN THE RIDGE AND EUGENE IS RESULTING IN FRESH 
NE WINDS FROM 19N TO 27N W OF 127W WHICH WAS EVIDENT IN 0200 UTC 
WINDSAT AND 0550 UTC ASCAT SCATTEROMETER PASSES. IN ADDITION...A 
SMALL AREA OF 20 KT TRADE WINDS ARE OCCURRING FROM 09N TO 12N W 
OF 136W.

A SURFACE TROUGH IS ALONG THE COAST OF MEXICO FROM 19N105W TO 
15N104W WITH SCATTERED MODERATE CONVECTION OCCURRING WITHIN 
45-60 NM EITHER SIDE OF THE TROUGH. ENVIRONMENTAL CONDITIONS ARE 
NOT CONDUCIVE FOR DEVELOPMENT OF THIS TROUGH AS IT MOVES OFF TO 
THE NW AROUND 10 KT PRIOR TO DISSIPATING IN 24-48 HOURS.

CROSS-EQUATORIAL SOUTHERLY SWELL IS BUILDING SEAS TO 10 FT S OF 
09N/10N W OF 100W. THIS SWELL OF 8-10 FT WILL GRADUALLY DECAY 
AND BECOME CONFINED TO W OF 110W IN 48 HOURS.

NORTHERLY WINDS WILL INCREASE TO 20 KT N OF 28N WITHIN 120 NM OF 
THE W COAST OF THE BAJA CALIFORNIA PENINSULA IN 18 HOURS AS THE 
PRES GRADIENT IN THE AREA TIGHTENS...DIMINISHING BY 48 HOURS.

$$
LEWITSKY