000
AXPZ20 KNHC 242143
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN MAY 24 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 96W FROM 04N-13N MOVING W AT 15 KT. DEEP 
CONVECTION ENHANCED HAS BEEN DIMINISHING LAST 24 HRS UNDER 
ADVERSE UPPER LEVEL SHEAR...BUT WAVE NOW ENTERING MORE FAVORABLE 
FLOW CONDUCIVE TO INCREASE CONVECTION MAINLY S OF ITCZ. 

...ITCZ...
AXIS ALONG 07N78W TO 08N88W TO 09N94W TO 10N102W TO 14N115W TO 
08N126W TO 06N140W.  SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 120 NM N AND 180 NM S OF AXIS E OF 96W.  
SCATTERED MODERATE CONVECTION WITHIN 120 NM S OF AXIS FROM 
99W-113W AND WITHIN 60 NM S OF AXIS FROM 123W-130W.

.DISCUSSION...
DRY QUASI-ZONAL WESTERLIES CONTINUE FLOWING ACROSS E PAC N OF 
20N...BUT NOW ONLY COVER E OF 120W AS TROPICAL MOISTURE FROM 
UPPER LEVEL TROUGH APPROACHING 140W IS ADVECTED INTO BASIN.  
DRY POCKET REMAINS W OF 128W FROM 08N-18N DOOMS REMNANTS OF 
SURFACE LOW PRES NOW A WEAK TROUGH FROM 09N-15N ALONG 129W.  

SECOND SURFACE TROUGH...ALSO REMNANTS OF PREVIOUS LOW PRES... 
FROM 10N-17N ALONG 116W STILL ABLE TO LIFT MINOR SCATTERED 
CONVECTION IN ITS WAKE.  TROUGH EXPECTED TO LAST 24-48 HRS 
BEFORE IT ENTERS DRY HOSTILE ENVIRONMENT AND BECOMES HARD TO 
DEFINE. 

SEVERAL MID TO UPPER LEVEL ANTICYCLONES FORM E-W ELONGATED RIDGE 
ALONG 10N ADVECTING ABUNDANT TROPICAL CONVECTIVE DEBRIS EASTWARD 
ALONG ITS NORTHERN PERIPHERY S OF 18N INTO CENTRAL AMERICA AND 
WESTERN CARIBBEAN WHERE DAYTIME HEATING PRODUCE CONVECTION OVER 
LAND AREAS.

.ELSEWHERE AT THE SURFACE...SURFACE HIGH PRES 1029 MB WELL N OF 
AREA HAS RIDGE EXTEND TO 18N120W PRODUCING GALE FORCE WINDS 
ALONG NORTHERN CALIFORNIA COAST.  MODERATE SWELL TRAINS MOVE S 
INTO E PAC WATERS N OF 28N.

$$
WALLY BARNES