000
AXPZ20 KNHC 231015
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU JUL 23 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 
0900 UTC.

...TROPICAL WAVES...
TROPICAL WAVE N OF 04N ALONG 86W MOVE W AT 25 KT HAS ITS N HALF 
UNDER AREA OF UPPER LEVEL DIFFLUENCE ASSOCIATED WITH ANTICYCLONE 
CENTERED OVER GULF OF HONDURAS IN WRN CARIBBEAN.  SCATTERED 
MODERATE TO STRONG CONVECTION HAS BEEN FLARING UNDER THIS 
FAVORABLE ENVIRONMENT ALOFT LIKELY TO CONTINUE FOR NEXT 48 HRS. 
   
TROPICAL WAVE N OF 04N ALONG 98W MOVE W AT 20 KT HAS DIMINISHING 
CONVECTION AS UPPER LEVEL CYCLONE PRESENTS STRONG S-SW SHEAR 
JUST N OF ITCZ.  CONVECTION S OF ITCZ HAS LESS ADVERSE 
CONDITIONS AND EXPECTED TO LAST LONGER. 

TROPICAL WAVE FROM 05N TO 14N ALONG 128W MOVE W AT 15 KT INTO  
AREA OF DRY AND STRONG SW UPPER SHEAR INHIBITING CONVECTION.    
CONVECTION CONTINUES TO STRETCH FROM NE TO SW FROM 10N TO 14N.

MODEL GUIDANCE HAVE TEMPERED ITS SOLUTION OF LOW PRES 
DEVELOPMENT BUT KEEP FRESH BREEZE ASSOCIATED TO WAVE THROUGH ITS 
CROSSING OUT OF BASIN WITHIN 48 HRS. 
 
...ITCZ...
AXIS ALONG 07N78W TO 09N93W TO 06N110W TO 10N124W TO 09N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM N OF 
AXIS E OF 90W.  SCATTERED MODERATE CONVECTION WITHIN 120 NM S OF 
AXIS W OF 130W.   

...DISCUSSION...
UPPER LEVEL CYCLONE CENTERED AT 11N107W KEEPS A DRY AIR MASS 
POCKET 300 NM FROM CENTER WITHIN LARGE AREA OF TROPICAL MOISTURE 
ASSOCIATED WITH ITCZ.  THIS CURTAILS CONVECTION DEVELOPMENT IN N 
SIDE OF TROPICAL WAVE AS AXIS APPROACHES CYCLONE. 

DEEP AMPLITUDE UPPER LEVEL TROUGH CONTROLS FLOW W OF 120W WITH 
DRY STABLE AIR MASS WITHIN 500 NM W OF ITS AXIS FROM 32N125W TO 
20N118W TO 14N127W.    

GAP WINDS...NE TO E FRESH BREEZE IN AND JUST DOWNSTREAM OF GULF 
OF PAPAGAYO EXPECTED THROUGH NEXT 48 HRS.

LONG PERIOD S SWELLS TOPPING 13 FT ARE CROSSING EQUATOR THROUGH 
TROPICAL E PACIFIC AND REACHING COAST OF CENTRAL AMERICA LATE 
THU AND AS FAR N AS CENTRAL BAJA PENINSULA LATE FRI.

$$
WALLY BARNES