000
AXPZ20 KNHC 110940
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT SEP 11 2010

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.

...ITCZ...
AXIS ALONG 10N85W TO 12N98W TO 10N110W TO 13N120W TO 13N133W TO 
11N140W.  ISOLATED MODERATE WITHIN 120 NM N AND 45 NM S OF AXIS 
FROM 110W TO 136W.

...DISCUSSION...
SHARP SLIGHTLY NEGATIVELY TILTED UPPER LEVEL TROUGH ENTERS NW 
CORNER OF E PAC FROM 32N131W S-SE TO CYCLONE AT 18N127W.  TROUGH 
SPLITS W ANTICYCLONE AT 18N142W FROM LARGE ONE OVER TEXAS BIG 
BEND.  MODERATE SUBSIDING AIR MASS MAINTAINS DRY AND STABLE 
CONDITION N OF 17N W OF 125W.  UPPER LEVEL CYCLONE LIKELY TO 
REMAIN TRAPPED IN PLACE OR DRIFT SW WHILE PARENT TROUGH SHIFTS 
NE TOWARDS CALIFORNIA COAST BY LATE MON.

LARGE ANTICYCLONE OVER TEXAS BRINGS ITS STRONG FLOW AROUND 
SOUTHERN PERIPHERY ACROSS CENTRAL AMERICA ADVECTING ABUNDANT 
TROPICAL MOISTURE INTO E PAC.  IT ALSO BRINGS UPPER SHEAR THAT 
CURTAILS DEEP CONVECTION EVEN ALONG ITCZ WHICH HAS BEEN 
UNUSUALLY QUIET AT THIS TIME OF THE YEAR.  SOME MOISTURE TAGS 
ALONG ITCZ AND FEEDS WEAK LOW PRES CENTER DEVELOPING WITHIN  
NEXT 24 HRS NEAR 13N133W.   

AT THE SURFACE...
WEAKENING HIGH PRES CENTER 1025 MB WELL NW OF BASIN HAS 
ASSOCIATED RIDGE EXTENDING SE THROUGH 23N123W.  HIGH PRES  
COVERS THE AREA N OF 20N W OF 120W.  DEVELOPING LOW PRES NEAR 
13N133W INCREASES WIND TO FRESH BREEZE AND 9 FT SEAS MAINLY 
AROUND NW SEMICIRCLE OF CENTER BY 48 HRS.

$$
WALLY BARNES