000
AXPZ20 KNHC 091610
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE DEC 09 2008

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 
1515 UTC.

...ITCZ...
AXIS ALONG 05N78W TO 09N111W TO 08N121W TO 12N128W TO 09N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM OF 
09N121W AND WITHIN 60 NM S OF AXIS E OF 84W.

...DISCUSSION...
MID/UPPER LEVEL TROUGH EXTENDS FROM 32N139W TO WELL DEFINED 
CYCLONIC VORTEX AT 23N137W TO 10N136W DRIFTING NW.  ABUNDANT 
MOISTURE AND SCATTERED DEEP CONVECTION IN E SEMICIRCLE OF CENTER 
UNDER MODERATE DIFFLUENT FLOW ALOFT WHILE DRY AIR MASS COVER SW 
QUADRANT OF VORTEX AS INCOMING 85 KT JET CORE CREATES AREA OF 
MODERATE TO STRONG SUBSIDENCE.  DOWNSTREAM...UPPER LEVEL RIDGE 
WITH AXIS FROM 32N12W TO 15N116W PUSHES INCOMING MOISTURE 
FURTHER E INTO CENTRAL MEXICO.  LARGE AMPLITUDE TROUGH AXIS DIGS 
FROM HONDURAS TO CYCLONIC VORTEX AT 04N94W MAKING AREA W OF 95W 
VERY DRY.

AT THE SURFACE...
STRONG COLD FRONT CROSSING ERN GULF OF MEXICO LATE THU WILL 
FORCE COLD AIR ACROSS ISTHMUS OF TEHUANTEPEC WITH WINDS BUILDING 
UP TO GALE FORCE STRENGTH BY 48 HRS.  GULF OF PAPAGAYO FRESH 
BREEZE LIKELY ABATE WITHIN 6 HRS ONLY TO BE REINFORCED BY END OF 
FORECAST PERIOD AND START ANOTHER EPISODE OF STRONG 
NORTHEASTERLIES.  

STATIONARY TROUGH FROM 17N131W TO 1009 MB LOW PRES NEAR 12N130W 
TO 07N132W.  LOW PRES WEAKENING AS IT MOVES N AND DISSIPATES 
WITHIN 48 HRS.  HIGH PRES CENTERED WELL N OF AREA AT 40N130W 
FORCES STRONG NW WINDS AGAINST BAJA CALIFORNIA COAST THROUGH 
NEXT 48 HRS.
 
$$
WALLY BARNES