000
AXPZ20 KNHC 010252
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU SEP 01 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 
0245 UTC.

...SPECIAL FEATURES...
THE LAST ADVISORY ON TROPICAL DEPRESSION EIGHT-E WAS ISSUED AT 
01/0300. AT THIS TIME...IT IS CENTERED NEAR 19.8N 103.8W MOVING 
NW AT 10 KT. MAXIMUM SUSTAINED WIND SPEED IS 20 KT WITH GUSTS TO 
30 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. HEAVY 
RAINFALL WILL CONTINUE FOR A FEW MORE HOURS ALONG THE W COAST OF 
MEXICO FROM 18N TO 22N.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH IS FROM 09N84W TO 16N95W THEN INLAND ACROSS 
SW MEXICO TO DISSIPATING TROPICAL DEPRESSION EIGHT-E NEAR 
20N104W THEN TO 18N120W TO 10N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS ALONG THE COAST OF MEXICO AND 
ADJACENT WATERS BETWEEN 102W AND 104W AND FROM 19N TO 21N. 
SIMILAR CONVECTION IS NOTED NEAR WITHIN 30 NM OF 18N107W. 

...DISCUSSION...
AN UPPER LEVEL TROUGH IS CLIPPING THE NW CORNER OF THE FORECAST 
AREA. AN UPPER LEVEL ANTICYCLONE CENTERED OVER SE OKLAHOMA 
EXTENDS A RIDGE SW ACROSS NW MEXICO AND THE BAJA CALIFORNIA 
PENINSULA TO 25N117W. A SECOND ANTICYCLONIC CIRCULATION IS 
LOCATED OVER WESTERN PORTIONS OF THE FORECAST REGION NEAR 
16N137W. STRONG UPPER LEVEL SUBSIDENCE AND THE IMPLIED DRY AIR 
MASS IS NOTED N OF 20N W OF 115W AND NW OF A LINE FROM 20N125W 
TO 10N140W. AN UPPER LEVEL TROUGH LIES SOUTH OF THE SECOND 
ANTICYCLONE AND RUNS FROM THE NORTHERN PORTION OF THE STATE OF 
COAHUILA MEXICO TO A WEAK UPPER LEVEL LOW NEAR 23N115W. UPPER 
LEVEL NE FLOW AND ABUNDANT MID/UPPER LEVEL MOISTURE DOMINATE 
MOST OF THE EPAC E OF 110W.   

AT THE SURFACE...A RIDGE REMAINS IN CONTROL OF THE WEATHER 
PATTERN N OF 20N W OF 120W. THE TIGHT PRES GRADIENT ASSOCIATED 
WITH THIS RIDGE IS RESULTING IN NLY WINDS OF 20 KT N OF 27N 
BETWEEN 125W AND 132W...AND  FROM 20N TO 27N W OF 132W. A PAIR 
OF ASCAT PASSES CONFIRMED THESE WIND SPEEDS. THE ASSOCIATED 
NORTHERLY SWELL IS MIXING WITH CROSS EQUATORIAL SOUTHWESTERLY 
SWELL RESULTING IN COMBINED SEAS OF 8 TO 10 FT. THE WINDS ARE 
FORECAST TO DIMINISH BELOW 20 KT TODAY...BUT SWELL WILL CONTINUE 
TO IMPACT MOST OF THE REGIONAL WATERS. THE SWELL HEIGHTS ARE 
EXPECTED TO GRADUALLY SUBSIDE OVER THE NEXT COUPLE OF DAYS.  
 
$$
GR