000
AXPZ20 KNHC 250310
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAY 25 2009

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 
0345 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 98W FROM 03N-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 ALONG ITCZ. 

...ITCZ...
AXIS ALONG 07N77W TO 07N90W TO 09N96W TO 09N100W TO 13N115W TO 
06N135W TO 06N140W.  SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 90 NM OF AXIS E OF 95W.  SCATTERED MODERATE 
CONVECTION WITHIN 90 NM S OF AXIS FROM 100W-108W AND WITHIN 60 
NM S OF AXIS FROM 121W-135W.

.DISCUSSION...
DRY QUASI-ZONAL WESTERLIES CONTINUE FLOWING ACROSS E PAC N OF 
20N...BUT NOW ONLY COVER E OF 117W AS TROPICAL MOISTURE FROM 
UPPER LEVEL TROUGH APPROACHING 140W IS ADVECTED INTO BASIN.  
DRY POCKET REMAINS W OF 126W FROM 08N-17N DOOMS REMNANTS OF 
SURFACE LOW PRES NOW A WEAK TROUGH FROM 09N-14N ALONG 131W.  

SECOND SURFACE TROUGH...ALSO REMNANTS OF PREVIOUS LOW PRES... 
FROM 10N-18N ALONG 117W 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 1030MB WELL N OF 
AREA HAS RIDGE EXTEND TO 20N115W PRODUCING GALE FORCE WINDS 
ALONG NORTHERN CALIFORNIA COAST.  MODERATE SWELL TRAINS SPREAD S 
INTO E PAC WATERS N OF 29N...BUT SUBSIDE WITHIN 24 HRS...ONLY TO 
RETURN LATE TUE.

$$
WALLY BARNES