000
AXPZ20 KNHC 230333
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED MAY 23 2007

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 
0300 UTC.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS ALONG 12N87W 9N102W 10N114W 
5N140W.  SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 
NM OF COASTS OF COSTA RICA AND NICARAGUA.  SCATTERED MODERATE TO 
STRONG CONVECTION WITHIN 180 NM OF AXIS FROM 101W TO 108W. 

...DISCUSSION...
LONGWAVE MID AND UPPER LEVEL TROUGH EXTENDS FROM 32N126W TO CUT 
OFF CYCLONIC VORTEX AT 27N136W.  VERY DRY AIR MASS ALOFT N OF 
20N W OF 110W DUE TO MODERATE TO STRONG SUBSIDENCE CURTAILS ANY 
CONVECTIVE DEVELOPMENT IN AREA.  

ANTICYCLONIC CIRCULATION CENTER AT 12N119W HELPS ANCHOR MID TO 
UPPER LEVEL RIDGE ACROSS ENTIRE BASIN S OF 17N.  ABUNDANT 
TROPICAL MOISTURE AVAILABLE S OF 17N BUT WEAK JET CORE UNABLE TO 
ADVECT IT THROUGH DRY AREA N OF 17N.  SECOND ANTICYCLONE OVER 
GUATEMALA PACIFIC COAST PROVIDES GOOD UPPER E FLOW WITH PLENTY 
OF MOISTURE INTO ITCZ.  WEAK DEFORMATION ZONE BETWEEN 
ANTICYCLONES PROVIDES UPPER LEVEL DIFFLUENCE TO DEVELOP STRONG 
CONVECTIVE CLUSTERS NEAR 11N109W.        

AT THE SURFACE...
HIGH PRES CENTER 1029 MB AT 37N136W HAS RIDGE EXTEND TO 15N105W 
HELPING SUFFOCATE ANY CONVECTIVE DEVELOPMENT.  MODERATE NE 
TRADES LOSING ITS SUPPORT AS HIGH PRES DRIFTS N AND WEAKENS.  

INCREASING CROSS EQUATORIAL SW FLOW S OF 8N E OF 90W WILL HELP 
BRING WARM MOIST AIR MASS INTO WEAK TROUGH CROSSING COSTA RICA 
INTO E PAC FROM CARIBBEAN BASIN.  THIS COULD STRENGTHEN TROUGH 
AS UPPER CONDITIONS ARE NOT UNFAVORABLE AT THIS TIME.     

$$
WALLY BARNES