000
AXPZ20 KNHC 020317
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE AUG 02 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 
0300 UTC.

...SPECIAL FEATURES...
HURRICANE EUGENE AT 13.2N 106.8W AT 02/0300Z MOVING W-NW OR 290 
DEGREES AT 11 KT WITH CENTRAL PRES 990 MB. MAXIMUM SUSTAINED 
WIND 65 GUSTS TO 80 KT. NUMEROUS STRONG CONVECTION WITHIN 120 
NM OF CENTER WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION 
ELSEWHERE WITHIN 240 NM W SEMICIRCLE. ALTHOUGH EUGENE REMAINS A 
MINIMAL HURRICANE...IT IS EXPECTED TO INTENSIFY AS UPPER LEVEL 
AND SEA SURFACE CONDITIONS REMAIN HIGHLY FAVORABLE FOR ITS 
DEVELOPMENT. 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.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 90W-91W ENTERING BAY OF CAMPECHE TONIGHT 
BRINGS ABUNDANT TROPICAL MOISTURE INTO A LOW PRES 1008 MB OVER 
GULF OF TEHUANTEPEC. WAVE ALSO PROMPTING FRESH N BREEZE FLOW 
ACROSS CHIVELAS PASS INTO GULF OF TEHUANTEPEC ENHANCING 
PROBABILITY OF INTENSIFICATION OF LOW PRES THERE. WAVE IS 
EVENTUALLY ABSORBED BY MONSOON TROUGH BY TUE. 

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 15N98W THEN CONTINUES 
FROM 13N110W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 150 NM OF AXIS FROM 93W TO 98W AND WITHIN 120 
NM N OF AXIS FROM 120W TO 122W.

...DISCUSSION...
LARGE AMPLITUDE DEEP LAYER TROUGH FROM 32N137W TO DEVELOPING 
CYCLONIC VORTEX AT 23N139W BEING BLOCKED FROM MOVING EASTWARD BY 
SMALL ANTICYCLONE AT 22N127W. AIR MASS REMAINS VERY DRY N OF 
MONSOON TROUGH AND W OF 122W BY MODERATE TO STRONG SUBSIDENCE. 
SMALL UPPER LEVEL ANTICYCLONIC GYRE OVER EUGENE FORMED WITHIN SW 
PORTION OF LARGE RIDGE THAT COVER MOST OF CONUS. SECOND ILL- 
DEFINED CYCLONE FORMING OVER YUCATAN PENINSULA BRINGS MODERATE 
NE SHEAR OVER SURFACE LOW PRES 1008 MB IN GULF OF TEHUANTEPEC 
INHIBITING DEVELOPMENT...ALTHOUGH LOW LEVEL VERY MOIST AIR MASS 
CONVERGENCE AND WARM SEA SURFACE TEMPERATURES ARE FAVORABLE. 

ELSEWHERE AT THE LOW LEVELS...
WEAKENING SUBTROPICAL HIGH PRES DRIFT SE TIGHTENING GRADIENT 
WITH DISSIPATING LOW PRES AT 10N131W FORCING FRESH NE TRADES 
FROM 05N TO 10N W OF 135W. TRADES ARE SHORT-LIVED AS LOW PRES 
DISSIPATES RELAXING GRADIENT. 

$$
WALLY BARNES