000
AXPZ20 KNHC 072147
TWDEP 

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

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH AXIS FROM 10N85W TO 12N103W TO 08N120W THEN ITCZ 
TO 11N140W.  SCATTERED MODERATE ISOLATED STRONG WITHIN 210 NM OF 
AXIS FROM 92W TO 96W.  SCATTERED MODERATE ISOLATED STRONG WITHIN 
180 NM S OF AXIS FROM 102W TO 107W. 

...DISCUSSION...
BROAD MID TO UPPER LEVEL ANTICYCLONIC GYRE CENTERED OVER 
NORTHERN MEXICO AT 30N108W MAINTAINS STEADY FLOW ACROSS BASIN N 
OF 16N INCLUDING A DIVERGING AREA OVER REMNANTS OF EUGENE...NOW 
NEAR 20N132W.  GYRE BLOCKS APPROACHING LONGWAVE UPPER LEVEL 
TROUGH FROM ENCROACHING FURTHER INTO BASIN ALLOWING STATIONARY 
SURFACE HIGH PRES 1035 MB RIDGE ACROSS MOST OF BASIN N OF ITCZ/ 
MONSOON TROUGH.  ONLY SHARP UPPER LEVEL TROUGH FROM CENTRAL 
MEXICO TO 11N107W 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 
110W DENIES ENERGY SUPPLY TO DEVELOP CONVECTION ALONG AXIS.

ELSEWHERE AT THE LOW LEVELS...
BROAD SURFACE HIGH PRES 1032 MB WELL NW OF BASIN HAS RIDGE 
EXTEND SE TO 17N110W DENTED ONLY BY REMNANTS OF EUGENE NOW AT 
20N132W.  DRY STABLE AIR MASS ACROSS WESTERN HALF OF BASIN 
CONTRIBUTED TO DISSIPATE PREVIOUS W-DRIFTING SURFACE LOW PRES AS 
ENVIRONMENT REMAINS UNFAVORABLE FOR DEVELOPMENT.  BURST OF 
CONVECTION NEAR 10N106W 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 MON.  NE SWELLS WITH SEAS 8-9 FT 
LINGER N OF 20N W OF 132W ONCE EUGENE BECOMES AN OPEN TROUGH 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