000
AXPZ20 KNHC 241026
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JAN 24 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 
0930 UTC.

...ITCZ...
ALONG 04N77W TO 02N83W TO 03N92W TO 01N106W TO 06N120W TO 
05N140W.  SCATTERED MODERATE CONVECTION 90 NM S OF AXIS E OF 83W.

...DISCUSSION...
DEEP LAYER TROUGH SUPPORTING WEAKENING SURFACE TROUGH ENTERING 
NW CORNER OF BASIN HAS CUT OFF VORTEX AT 32N132W DRIFTING NE 
PULLING ITS SUPPORT OF SURFACE FEATURE AND ACCELERATING ITS 
DEMISE.  NARROW DOWNSTREAM RIDGE PUSHED BY FORMING CYCLONIC 
VORTEX ALSO HAS LARGE AREA OF MODERATE TO STRONG SUBSIDENCE ON W 
SIDE MAINTAINING VERY DRY AIR MASS W OF 117W.  SECOND UPPER 
TROUGH EXTEND FROM CENTRAL MEXICO TO FORMING CYCLONIC VORTEX AT 
07N116W.  

CARIBBEAN STRONG NE WINDS CONTINUE UNDER INFLUENCE OF LARGE HIGH 
PRES RIDGE PRESENTLY OVER FLORIDA PENINSULA.  GFS GUIDANCE 
RELUCTANT TO WEAKEN THESE WINDS WHICH COME ACROSS CENTRAL 
AMERICA INTO GULFS OF PAPAGAYO...FONSECA AND PANAMA INTO E PAC  
WHILE I WOULD HAVE FORECAST THEIR DECREASE GIVEN THE EASTWARD 
DRIFT OF THE RIDGE.  WILL KEEP THE WINDS FOR THE DURATION OF 
FORECAST GIVEN THE ESTABLISHED GOOD HANDLE GFS HAS SHOWN WITH 
THESE WINDS.  

LOW PRES 1015 MB RIGHT AT EDGE OF FORECAST WATERS WITH WEAKENING 
TROUGH EXTENDING FROM 30N130W TO 25N135W WITH STRONG NE WINDS W 
OF AXIS.  

ANOTHER SURFACE TROUGH DEVELOPS WITHIN 30 HORS ALONG 123W WITH 
INCREASING NE WINDS JUST W OF AXIS.  WINDS OVER OPEN E PAC 
WATERS BARELY BUILDING SEAS AT ALL...BUT LONG PERIOD NW SWELLS 
HAVE SPREAD OVER MOST OF BASIN W OF 115W BRINGING SEAS AS HIGH 
AS 16 FT...HIGHEST CLOSE TO NW CORNER AND SUBSIDING AS SWELLS 
SPREAD SE. 

$$
WALLY BARNES