000
AXPZ20 KNHC 182158
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT SEP 18 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...
AXIS EXTENDS FROM 11N127W TO 09N140W. A MONSOON TROUGH AXIS 
EXTENDS FROM COSTA RICA TO 10N90W...BECOMING LESS DEFINED 
BETWEEN 90W AND 96W...CONTINUING FROM 13N96W TO A 1007 MB LOW AT 
16N106W TO 14N115W TO A 1008 MB LOW AT 13N125W TO 10N132W TO 
09N140W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 180 NM N 
OF TROUGH BETWEEN 100W AND 109W. SCATTERED MODERATE CONVECTION 
WITHIN 60 NM S OF ITCZ BETWEEN 136W AND 139W.

...DISCUSSION...
ALOFT...
A DEEP TROUGH IN THE NE PACIFIC APPROACHING THE OREGON COAST 
EXTENDS ACROSS FAR NW PORTION OF AREA FROM A LOW CENTERED NEAR 
43N133W TO NEAR 27N141W. POLAR JET DIVING FAR SOUTH TO NEAR 32N 
ALONG 137W...AND THE SUBTROPICAL JET IS ALSO DISPLACED SOUTH 
WITH AN ENTRANCE REGION NEAR 21N141W AND AN EXIT REGION OVER 
NEVADA. WATER VAPOR IMAGERY SHOWS A RIDGE EXTENDING WSW FROM AN 
ANCHOR ANTICYCLONE NEAR 25N116W TO BEYOND 140W AT 17N. VERY 
STRONG UPPER LEVEL EASTERLY WINDS ARE EVIDENT S OF 9N W OF 110W. 
DIVERGENT ANTICYCLONIC FLOW IS ENHANCING DEEP CONVECTION W OF 
THE PACIFIC COAST OF CENTRAL AMERICA FROM 95W TO 100W.

SURFACE...
DEEP LAYER TROUGH MENTIONED ABOVE IS PUSHING A WEAKENING COLD 
FRONT INTO NW PART OF THE DISCUSSION AREA. THE FRONT WILL STALL 
AND BECOME A STATIONARY FRONTAL BOUNDARY OVER THE NEXT 24-36 
HOURS. 1019 MB HIGH PRESSURE SE OF THE COLD FRONT NEAR 28N127W 
WILL BE IN A SQUEEZE PLAY BETWEEN THE FRONT TO THE NW AND A 
THERMAL TROUGH OVER BAJA CALIFORNIA...CAUSING 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 A STRING OF LOW PRESSURE SYSTEMS...A 1007 MB LOW NEAR 
16N106W...ANOTHER 1007 MB LOW NEAR 15N110W...AND A 1008 MB LOW 
NEAR 13N125W.

MARINE...
THE FRESH TO STRONG SW WINDS S OF THE MONSOON TROUGH AXIS ARE 
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