000
AXPZ20 KNHC 252143
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON MAY 25 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 105W FROM 03N TO 14N MOVING W AT 15 KT. 
UPPER LEVEL ENVIRONMENT HAS NOT TURNED AS FAVORABLE AS EXPECTED 
YESTERDAY...BUT HAS CEASED ITS ADVERSE INFLUENCE ON CONVECTION 
DEVELOPMENT.  AIR MASS VERY DRY S OF ITCZ...BUT FAIRLY MOIST N 
OF IT WITH SCATTERED MODERATE CONVECTION RUNNING WITHIN 360 NM
W OF WAVE AXIS.

...ITCZ...
AXIS ALONG 06N77W TO 09N100W TO 08N115W TO 10N126W TO 05N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 180 NM OF 
AXIS E OF 97W.  SCATTERED MODERATE CONVECTION WITHIN 240 NM OF 
AXIS W OF 124W.

.DISCUSSION...
UPPER LEVEL TROUGH EXTENDS SW ALONG 32N114W TO 17N131W BARELY 
NOTICEABLE IN QUASI-ZONAL FLOW THAT CONTINUES N OF 17N W OF 97W. 
MOISTURE HAS NOW ENCROACHED INTO E PAC FROM SEVERAL SOURCES WITH 
PATCHES OF DRY AIR MASS NOW LOSING COVERAGE.  JET CORE 75 KTS 
ADVECTS PLENTY OF MOISTURE ALONG 25N WHILE RIDGE ALONG 09N-12N 
MAINTAINS MOISTURE DEBRIS FROM ITCZ CONVECTION FLOWING EASTWARD 
S OF 17N INTO CENTRAL AND SOUTH AMERICA BESIDES INTO WESTERN 
CARIBBEAN.

UPPER LEVEL ANTICYCLONE OVER GULF OF PANAMA HAS RIDGE EXTEND W 
ALONG 09N-12N PROVIDING GOOD OUTFLOW TO SURFACE EQUATORIAL 
TROUGH CONVECTION AND ITCZ TO 97W.

.ELSEWHERE AT THE SURFACE...
HIGH PRES CENTER 1027 MB WELL N OF AREA DRIFTING S EFFECTIVELY 
HELPED DISSIPATE BOTH TROUGHS PREVIOUSLY W OF 120W AND SHUT DOWN 
NE TRADE WINDS.  SMALL AREA OF N SWELLS TO 8-10 FT EXPECTED TO 
CONTINUE OVER DISCUSSION AREA N OF 28N FROM 120W TO 125 THROUGH 
WED.  

$$
WALLY BARNES