000
AXPZ20 KNHC 052135
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURES...

T.S. EUGENE IS CENTERED NEAR 18.2N 124.5W AT 05/2100 UTC MOVING 
W-NW OR 285 DEGREES AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 
IS 997 MB. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO 50 KT WITH 
GUSTS TO 60 KT. ADDITIONAL WEAKENING IS FORECAST AS THE CYCLONE 
TRAVERSES COLDER WATER AND AN INCREASINGLY MORE STABLE 
ENVIRONMENT. EUGENE WILL LIKELY BECOME A REMNANT LOW BY SUNDAY. 
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 07N78W TO 09N90W TO 12N101W THEN 
RESUMES NEAR 14N129W TO 11N133W. THE INTERTROPICAL CONVERGENCE 
ZONE AXIS EXTENDS FROM 11N133W TO 09N140W. SCATTERED MODERATE 
CONVECTION IS NOTED FROM 06N TO 10N BETWEEN 94W AND 100W...AND 
FROM 08N TO 11N W OF 134W. 

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 28N115W WITH AN 
UPPER RIDGE EXTENDING SW TO A COL NEAR 21N132W. TROPICAL CYCLONE 
EUGENE CONTINUES TO MOVE WNW AROUND THE SOUTHERN PERIPHERY OF 
THIS RIDGE. AN UPPER LEVEL TROUGH IS CLIPPING THE FAR NW CORNER 
OF THE AREA AND 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 UPPER LEVEL WINDS DOMINATE THE REMAINDER OF THE 
DISCUSSION AREA.

AT THE SURFACE...1035 MB HIGH PRES CENTERED NW OF THE FORECAST 
REGION NEAR 40N152W EXTENDS A RIDGE OVER THE NORTH WATERS N OF 
22N. THE PRES GRADIENT BETWEEN THE RIDGE AND EUGENE IS RESULTING 
IN FRESH NE WINDS N OF 20N W OF 122W. THE 1430 UTC WINDSAT PASS 
ALONG WITH THE 1814 ASCAT PASS PROVIDED OBSERVATIONS OF THESE 
WIND SPEEDS. 

THE 1814 ASCAT OVERPASS EUGENE SHOWING A MAXIMUM INTENSITY OF 
AROUND 40 TO 50 KT. THE FRESH TO STRONG WINDS EXTEND AS FAR AS 
240 NM N SEMICIRCLE AND 180 NM S SEMICIRCLE. MODERATE TO FRESH 
S TO SW WINDS CONTINUE TO FEED INTO EUGENE FROM N OF 10N BETWEEN 
121W AND 127W ACCORDING TO THE SAME SCATTEROMETER DATA. 

A WEAK AREA OF LOW PRESSURE CENTERED NEAR 18N106.5W OR ABOUT 130 
MILES SW OF MANZANILLO MEXICO CONTINUES TO PRODUCE DISORGANIZED 
SHOWER AND THUNDERSTORM ACTIVITY PARTICULARLY FROM 16N TO 20N 
BETWEEN 105W AND 108W. ENVIRONMENTAL CONDITIONS ARE NOT 
CONDUCIVE FOR DEVELOPMENT...AND THIS SYSTEM HAS A LOW CHANCE OF 
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES 
WEST-NORTHWESTWARD NEAR 10 MPH.

CROSS-EQUATORIAL SOUTHERLY SWELL CONTINUES TO PROPAGATE ACROSS 
THE REGIONAL WATERS MAINLY S OF 10N AND W OF 100W BUILDING SEAS 
TO 10 FT. THIS SWELL EVENT WILL GRADUALLY DECAY AND BECOME 
CONFINED TO W OF 115W IN 24 HOURS...AND W OF 120W 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 ABOUT 12 HOURS 
AS THE PRES GRADIENT IN THE AREA TIGHTENS. WINDS ARE FORECAST TO 
BE BELOW 20 KT BY 36 HOURS.

$$
GR