000
AXPZ20 KNHC 020915
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI SEP 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH 17N100W 15N110W 17N120W 12N140W. SCATTERED 
MODERATE TO STRONG CONVECTION FROM 6N-12N BETWEEN 85W-90W AND 
FROM 5N-8N BETWEEN 97W-104W.

...DISCUSSION...
AN UPPER LEVEL TROUGH DOMINATES THE NW CORNER OF THE DISCUSSION 
AREA AND EXTENDS FROM A CUT-OFF LOW NEAR 29N130W TO 18N138W.
MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR AT THE MIDDLE 
AND UPPER LEVELS IS N OF 15N W OF 115W. AN ANTICYCLONIC 
CIRCULATION OVER CENTRAL MEXICO WITH A RIDGE EXTENDING W TO 
18N122W. NE WINDS TO THE S OF THIS RIDGE ARE NOTED E OF 110W. 
DIFFLUENCE ASSOCIATED WITH THESE WINDS ALOFT ARE HELPING TO 
INDUCE CONVECTION W OF COSTA RICA.   

WEAK SURFACE HIGH PRESSURE RIDGE OVER NW PORTION OF THE AREA 
WITH A VERY WEAK PRES PATTERN LEADING TO LIGHTER THEN NORMAL 
TRADES ACROSS THE AREA. HOWEVER SW WINDS TO 20 KT ARE FROM 10-15 
KT BETWEEN 105W-115W. OTHERWISE SW SWELLS PROPAGATING FROM THE 
SOUTHERN HEMISPHERE ARE S OF 20N BETWEEN 80W-125W.

WINDS ARE EXPECTED TO INCREASE SOME JUST W OF THE BAJA 
CALIFORNIA PENINSULA AS PRES GRADIENT TIGHTENS ACROSS THE AREA. 
MARINE GUIDANCE SUGGESTS NW WINDS OF 20 KT AND SEAS TO 8 FT.

$$
DGS