000
AXPZ20 KNHC 151600
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED SEP 15 2010

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
AXIS FROM 15N92W TO 13N99W TO 12N108W TO 12N124W TO 10N135W... 
THEN RESUMING NEAR 10N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 90 NM OF LINE FROM 11N89W TO 15N100W...AND 
FROM 09N TO 11N BETWEEN 96W AND 100W...AND WITHIN 180 NM OF AXIS 
BETWEEN 117W AND 129W.

...DISCUSSION...
ALOFT...
SHARP UPPER LEVEL TROUGH APPROACHING CALIFORNIA CROSSES BASIN 
FROM 32N123W TO 26N130W TO 25N140W SUPPORTING STRONG SUBSIDENCE 
AND VERY DRY AIR MASS NEAR ITS AXIS. ANTICYCLONES CENTERED JUST 
WEST OF BAJA CALIFORNIA NEAR 24N114W AND OVER CENTRAL MEXICO. A 
STRONG TROUGH SEPARATING THE TWO EXTENDS FROM 30N102W ACROSS NW 
MEXICO THROUGH 24N106W TO 17N112W. TROUGH IS ADVECTING ABUNDANT 
TROPICAL MOISTURE ACROSS CENTRAL AMERICA INTO E PAC S OF 15N. E 
TO NE WIND FLOW ELSEWHERE IS STRONG ENOUGH TO SHEAR CYCLONIC 
DEVELOPMENT IN THE ITCZ.

SURFACE...
FRONTAL BOUNDARY NORTH OF THE AREA APPROACHING NRN CALIFORNIA IS 
EXERTING PRESSURE ON SUBTROPICAL HIGH IN NW PORTION OF DISCUSSION
AREA. PERSISTENT THERMAL TROUGH IS OVER THE GULF OF CALIFORNIA. 
FRESH WINDS W OF BAJA CALIFORNIA ARE EXPECTED TO DIMINISH AS HIGH
PRESSURE WEAKENS. EARLIER SCATTEROMETER DATA AND ANIMATED VISUAL 
IMAGERY SHOW A VERY ACTIVE ITCZ...WITH STRONG E-W SHEAR VORTICITY
NOTED W OF 112W BETWEEN 10N AND 13N. NOT SURPRISINGLY...A LOW IS 
STARTING TO DEVELOP NEAR 11N108W. MODEL GUIDANCE INDICATES THIS 
FEATURE IS LIKELY TO INTENSIFY FURTHER OVER THE NEXT 24-48 HOURS.
GLOBAL MODELS HINT AT LOW PRES POSSIBLY FORMING BETWEEN 107W AND 
110W NEAR 11N THE NEXT COUPLE OF DAYS...WITH FRESH TO STRONG SW 
WINDS DEVELOPING IN ITS S SEMICIRCLE ALONG WITH SEAS UP TO 10 FT 
IN LATEST WAVEWATCH GUIDANCE.

MARINE...
CROSS EQUATORIAL LONG PERIOD SWELLS SPREADING NORTHWARD ARE 
EXPECTED TO REACH AS FAR NORTH AS 16N. LARGE SURF ALONG EXPOSED 
COASTS IS POSSIBLE THE NEXT FEW DAYS FROM SEAS UP TO 12 FT. HIGH 
SEAS AND STRONG SW WINDS ASSOCIATED WITH LOW DEVELOPMENT IN THE 
MONSOON TROUGH INDICATED BY WW3 GUIDANCE FROM 8N TO 13N BETWEEN 
101W AND 115W.

$$
MUNDELL