000
AXPZ20 KNHC 181605
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT SEP 18 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 EXTENDS FROM 10N128W TO 09N140W. SCATTERED MODERATE 
CONVECTION WITHIN 120 NM S OF AXIS W OF 136W. 

OTHER CONVECTION...
SCATTERED MODERATE TO STRONG CONVECTION FROM 12N TO 19N BETWEEN 
100W AND 108W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
FROM 06N TO 13N BETWEEN 88W AND 99W. SCATTERED MODERATE WITHIN 
210 NM NW QUADRANT OF LOW NEAR 12N125W.

...DISCUSSION...
ALOFT...
A DEEP TROUGH IN THE NE PACIFIC APPROACHING THE WEST COAST OF 
U.S. EXTENDS ACROSS THE NW PORTION OF AREA FROM A LOW CENTERED 
NEAR 43N133W TO NEAR 27N144W. POLAR JET DIVING FAR SOUTH TO NEAR 
33N ALONG 138W...AND THE SUBTROPICAL JET IS ALSO DISPLACED SOUTH 
WITH AN ENTRANCE REGION NEAR 21N140W AND AN EXIT REGION NEAR LAS 
VEGAS NEVADA. WATER VAPOR IMAGERY SHOWS A RIDGE EXTENDING WSW 
FROM AN ANCHOR ANTICYCLONE NEAR 24N114W TO BEYOND 140W AT 17N. 
VERY STRONG UPPER LEVEL EASTERLY WINDS ARE EVIDENT S OF 10N W OF 
95W. DIVERGENT ANTICYCLONIC FLOW IS ENHANCING DEEP CONVECTION 
ALONG THE WEST COAST OF CENTRAL AMERICA FROM 95W TO 107W.

SURFACE...
DEEP LAYER TROUGH IN NE PACIFIC IS PUSHING A COLD FRONT INTO NW 
PART OF THE DISCUSSION AREA. THIS FRONT IS EXPECTED TO GRADUALLY 
STALL AND BECOME A STATIONARY WEAKENING FRONTAL BOUNDARY OVER THE
NEXT 24-36 HOURS. HIGH PRESSURE SE OF THE COLD FRONT NEAR 29N125W
WILL BE IN A SQUEEZE PLAY BETWEEN THE COLD FRONT TO THE NW AND A 
THERMAL TROUGH OVER BAJA CALIFORNIA...RESULTING IN FRESH NE WINDS
ALONG THE WEST COAST OF BAJA N OF 26N THE NEXT TWO DAYS. SW WINDS
ASSOCIATED WITH ACTIVE MONSOON TROUGH E OF 125W IS BEING FOCUSED
BY LOW PRESSURE SYSTEMS...A 1007 MB LOW NEAR 15N112W AND ANOTHER 
1007 MB LOW NEAR 12N125W AND ANCHORED BY THE REMNANT LOW OF KARL 
OVER SOUTHERN MEXICO NEAR 18N98W.

MARINE...
THE FRESH TO STRONG SW WINDS S OF THE MONSOON TROUGH AXIS IS 
PRODUCING HIGH SEAS TO 12 FEET IN SE SEMICIRCLE AND IMMEDIATE 
VICINITY OF TROUGH AXIS. WW3 MODEL GUIDANCE SHOWS MINIMAL HIGH 
SEAS TO 8 FT BEHIND COLD FRONT...AND SW SWELLS GENERATED BY THE 
ACTIVE TROUGH SLOWLY PROPAGATING TOWARD THE WEST COAST OF MEXICO 
NEAR 18N104W. 

$$
MUNDELL