000
AXPZ20 KNHC 200330
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU NOV 20 2008

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...08N78W 
06N110W 07N140W. SCATTERED MODERATE WITHIN 90-120 NM OF AXIS W 
OF 133W...AND WITHIN 60 NM OF AXIS BETWEEN 107W AND 110W. 

...DISCUSSION...

UPPER LEVELS
LARGE UPPER TROUGH CONTINUES TO DOMINATE THE AREA. TROUGH AXIS 
EXTENDS FROM CENTRAL NEW MEXICO THROUGH 22N120W TO A DEVELOPING 
CYCLONIC CIRCULATION NEAR 14N123W. A NEGATIVELY TILTED EXTENSION 
OF THE TROUGH EXTENDS SE TO 03N110W. THIS TROUGH WILL SLOWLY 
WEAKEN TO A SHEAR AXIS THROUGH 24 HOURS BUT REMAIN IN PLACE. 
UPSTREAM POSITIVELY TILTED TROUGH WITH AN AXIS JUST TO THE NW OF 
THE AREA IS AFFECTING THE AREA NW OF A LINE FROM 32N122W TO 
20N140W. THE AREA NORTHWEST OF THE LINE IS MOIST ALOFT WITH 
BROKEN TO OVERCAST HIGH LEVEL CLOUDS. THE AREA BETWEEN THE FIRST 
TROUGH AXIS AND THE LEADING EDGE OF THE TROUGH WEST OF THE AREA 
IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS INDICATING 
SUBSIDENCE IN THIS AREA. SOUTHEAST OF THE FIRST TROUGH AXIS 
SOUTH TO SOUTHWESTERLY FLOW IS ADVECTION MOISTURE AND SOME 
MIDDLE AND HIGH LEVELS CLOUDS EMANATING FROM ITCZ CONVECTION 
OVER MEXICO AND CENTRAL AMERICA.  

SURFACE
A COLD FRONT LIES JUST TO THE NORTHWEST OF THE AREA AND IS 
EXPECTED TO MOVE INTO THE NW PORTION OF THE AREA AS A 
DISSIPATING FRONT OVER THE NEXT 12-24 HOURS. A 1022 MB HIGH NEAR 
31N128W HAS AN ASSOCIATED WEAK RIDGE EXTENDING SE TO 18N110W. 

GAP WINDS...
STRONG PRES GRADIENT REMAINS ACROSS ISTHMUS OF TEHUANTEPEC. A 
0012 UTC HIGH RESOLUTION QUIKSCAT PASS INDICATED NLY WINDS OF 
35-40 KT THEREBY INDICATING GALE CONDITIONS CONTINUE IN THE 
AREA. THESE WINDS ARE EXPECTED TO DROP BRIEFLY BELOW GALE FORCE 
IN ABOUT 24 HOURS BEFORE PICKING UP AGAIN IN YET ANOTHER SURGE 
OF NLY WINDS WHICH ARE EXPECTED TO REACH 40 KT OR SO BY LATE 
FRI. 

A 0000 UTC SHIP REPORT FROM THE SHIP WITH CALL SIGN 3FMH7 NEAR 
9.5N 86.5W OR ABOUT 75 NM SW OF THE GULF OF PAPAGAYO INDICATED 
NE WINDS OF 24 KT AND 8 FT SEAS. THESE WINDS ARE FORECAST TO 
SLOWLY WEAKEN IN THE 24-48 HOUR TIMEFRAME.

$$
COBB