000
AXPZ20 KNHC 020927
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE SEP 02 2008

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 0915 UTC.

...SPECIAL FEATURE...

LOW PRES NEAR 19N110W 1004 MB IS DRIFTING W TO WNW AT 5 KNOTS. 
SCATTERED TO NUMEROUS STRONG CONVECTION IS CONFINED TO WITHIN 
150 NM OF CENTER IN THE W SEMICIRCLE WITH THE LOW LEVEL CENTER
JUST TO THE E OF THE DEEP CONVECTION. CIMSS ANALYSES INDICATE 
THE SYSTEM IS EMBEDDED WITHIN AN AREA OF 20-25 KT EASTERLY
SHEAR. THE SHEAR IS FORECAST TO RELAX AND MORE FAVORABLE 
CONDITIONS ARE POSSIBLE FOR IT TO BECOME A TROPICAL DEPRESSION 
WITHIN THE NEXT 48 HOURS...NONETHELESS WITH THE SHEAR PRESENT  
ANY DEVELOPMENT SHOULD BE SLOW TO OCCUR.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N86W TO 12N100W TO 10N120W TO 
07N140W. SCATTERED MODERATE WITHIN 120 NM S OF THE AXIS BETWEEN 
95W AND 101W...AND BETWEEN 131W AND 137W.

...DISCUSSION...

A MID TO UPPER LEVEL RIDGE EXTENDS FROM AN ANTICYCLONE CENTERED 
JUST OFF BAJA CALIFORNIA NEAR 21N110W WWD ALONG 23N120W TO 
22N130W. MODERATE EASTERLY WINDS ARE NOTED S OF THE RIDGE AND 
ANTICYCLONE TO THE DEEP TROPICS. MODERATE TO STRONG SUBSIDENCE 
MAINTAINS VERY DRY AIR MASS N OF 14N W OF 120W...AND IS 
SUPPRESSING ANY DEEP CONVECTION. MAIN MOISTURE AREA IS 
ASSOCIATED WITH THE ITCZ AND NEAR THE LOW PRESSURE NEAR 19N110W. 

AT THE SURFACE...
RIDGE EXTENDS SE THROUGH 32N133W TO 25N120W WITH HIGH PRES 
COVERING THE AREA N OF 17N W OF 120W. 1029 MB PARENT HIGH NEAR 
39N141W IS INTERACTING WITH LOW PRES OVER THE SW UNITED STATES 
TO PRODUCE N-NE WINDS OF 20 KT OVER THE N AND NW PORTIONS OF 
THE AREA WITH SEAS UP TO 13 FT IN NE SWELL. THESE CONDITIONS ARE 
FORECAST TO SLOWLY SUBSIDE OVER THE NEXT 48 HOURS.

SW WIND FIELD S OF MONSOON TROUGH COMBINED WITH CROSS EQUATORIAL 
SWELLS ARE CAUSING 8-11 FT SEAS WITHIN 180 NM S OF LINE 12N94W
12N115W...AND ALSO FROM 5N TO 12N BETWEEN 91W AND 122W. THESE
CONDITIONS WILL LIKELY LAST THROUGH THE NEXT 2-3 DAYS BEFORE 
SUBSIDING. SOME OF THESE SWELLS MAY REACH THE CENTRAL AMERICAN 
COAST IN THE 8-9 FT RANGE. 

GLOBAL MODELS SUGGEST THAT A NEW LOW PRES AREA MAY FORM ON THE
EASTERN END OF THE MONSOON TROUGH OVER THE NEXT 2-3 DAYS...AND
FURTHER ENHANCE THE SW WINDS IN THIS AREA.

$$
COBB