000
AXPZ20 KNHC 130910
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI NOV 13 2009

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 
0800 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 07N78W 
TO 08N85W TO 07N100W TO 12N115W TO 11N133W TO 06N140W. ISOLATED 
MODERATE CONVECTION CAN BE FOUND WITHIN 60 NM EITHER SIDE OF THE 
ITCZ AXIS FROM 81W TO 99W. SCATTERED MODERATE CONVECTION CAN BE 
FOUND WITHIN 150 NM N OF THE ITCZ AXIS FROM 99W TO 115W. 
ISOLATED MODERATE CONVECTION LIES WITHIN 180 NM EITHER SIDE OF 
THE ITCZ AXIS FROM 115W TO 140W.

...DISCUSSION...
AN UPPER LEVEL TROUGH STRETCHES OVER THE N WATERS WITH A COLD 
FRONT DISSIPATING FROM 30N119W TO 20N126W TO 08N140W. THE UPPER 
JET ON THE LEADING EDGE OF THIS TROUGH IS TRANSPORTING MOISTURE 
ALOFT NORTHEASTWARD INTO SOUTHERN CALIFORNIA AND NORTHERN BAJA 
CALIFORNIA. A SURFACE HIGH PRES SYSTEM IS CENTERED NEAR 36N154W 
BEHIND THIS UPPER TROUGH...WITH A RIDGE ACCESS EXTENDING SE 
ACROSS THE N WATERS. A TIGHT PRES GRADIENT EXISTS N OF 08N WITH 
20 TO 30 KT EASTERLY TRADE WINDS OVER THIS AREA AROUND THE HIGH. 
WIND WAVES OF 8 TO 12 FT CONTINUE TO BE GENERATED BY THESE 
WINDS. THE HIGH N OF THE AREA AND THE TIGHT PRES GRADIENT OVER 
THE N WATERS WILL PERSIST THROUGH THE WEEKEND. A COLD FRONT 
APPROACHES THE NW WATERS EARLY NEXT WEEK AS HIGH PRES AND THE 
GRADIENT WEAKEN. 

TO THE S...AN ANTICYCLONE IS CENTERED NEAR 15N127W. AN UPPER 
LEVEL TROUGH LIES E OF THIS SYSTEM EXTENDING FROM CENTRAL MEXICO 
TO 16N112W BACK TO THE ANTICYCLONE. A CONFLUENT AIR MASS WITH
MODERATE TO STRONG SUBSIDING AIR N OF THIS TROUGH IS PRODUCING 
A DRY ATMOSPHERE. DIFFLUENT FLOW S OF THE TROUGH IS ENHANCING 
PLENTY OF CONVECTION ALONG A WEAK SURFACE TROUGH EXTENDING FROM 
06N138W TO 13N133W. MEANWHILE SOUTHERLY SWELL OF 8 TO 10 FT 
CONTINUES TO PROPAGATE THROUGH THE S WATERS. THIS SWELL WILL 
GRADUALLY SUBSIDE THROUGH THE WEEKEND...TO BELOW 8 FT BY MON.  

GAP WINDS...
A 0012 UTC QUIKSCAT PASS SHOWED GALE FORCE WINDS S OF THE 
ISTHMUS OF TEHUANTEPEC INTO THE PACIFIC. WINDS ARE FORECAST TO 
DIMINISH TO BELOW GALE FORCE WITHIN THE NEXT 6 HOURS AS THE PRES 
GRADIENT WEAKENS.

$$
LEWITSKY