000
AXPZ20 KNHC 071556
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN AUG 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH AXIS FROM 09N84W TO 12N101W TO LOW PRES 1009 MB 
NEAR 10N110W.  ITCZ AXIS FROM 10N110W TO 07N122W TO 12N140W. 
SCATTERED MODERATE FROM 08N TO 12N BETWEEN 90W AND 117W.

...DISCUSSION...
BROAD MID TO UPPER LEVEL ANTICYCLONIC GYRE CENTERED OVER 
NORTHERN MEXICO AT 31N10W MAINTAINS STEADY FLOW ACROSS BASIN N 
OF 16N INCLUDING A DIVERGING AREA OVER REMNANTS OF EUGENE...NOW 
NEAR 20.5N131.5W.  GYRE BLOCKS APPROACHING LONGWAVE UPPER LEVEL 
TROUGH FROM ENCROACHING FURTHER INTO BASIN ALLOWING SURFACE HIGH 
PRES 1035 MB RIDGE ACROSS MOST OF BASIN N OF ITCZ/MONSOON 
TROUGH.  ONLY SHARP UPPER LEVEL TROUGH FROM CENTRAL MEXICO TO 
10N103W INTERRUPTS TOTAL ANTICYCLONIC FLOW...WHILE INTRODUCING 
SMALL AREA OF DIVERGENCE ALOFT NEAR MONSOON TROUGH AXIS.

VERY DRY SUBSIDING AIR MASS S OF MONSOON TROUGH/ITCZ AXIS W OF 
100W DENIES ENERGY SUPPLY TO DEVELOP CONVECTION ALONG AXIS.

ELSEWHERE AT THE LOW LEVELS...
BROAD SURFACE HIGH PRES 1035 MB WELL NW OF BASIN HAS RIDGE 
EXTEND SE TO 15N110W DENTED ONLY BY REMNANTS OF EUGENE NOW AT 
20.5N131.5W.  WITH DRY STABLE AIR MASS ACROSS WESTERN HALF OF 
BASIN...LITTLE ACTION EXPECTED FORM W-DRIFTING SURFACE LOW PRES 
1009 MB PRESENTLY AT 10N110W AS ENVIRONMENT REMAINS UNFAVORABLE 
FOR DEVELOPMENT.  BURST OF CONVECTION WELL E OF LOW PRES MAINLY 
DUE TO DIVERGENT FLOW ALOFT ENHANCING UPLIFTING RATHER THAN 
SURFACE PROMPTED ACTION.  LITTLE OR NO TROPICAL ORGANIZATION 
EXPECTED ALONG MONSOON TROUGH/ITCZ DURING NEXT 48 HRS.  

TIGHT PRES GRADIENT BETWEEN HIGH PRES TO THE NW AND REMNANT OF 
EUGENE RESULT IN AREA SWATH OF NEAR GALE FORCE WINDS WITHIN 240 
NM N OF CENTER DIMINISHING LATE TONIGHT OR MON.  NE SWELLS WITH 
SEAS 8-9 FT LINGER N OF 20N W OF 132W ONCE EUGENE BECOMES AN 
OPEN TROUGH BY TUE.

CROSS-EQUATORIAL SOUTHERLY SWELL SPREAD ACROSS REGION S OF 10N W 
OF 100W WITH SEAS TO 9 FT REMAIN UNCHANGED THROUGH FORECAST 
PERIOD.

$$
WALLY BARNES