000
AXPZ20 KNHC 232149
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAY 23 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 
2115 UTC.

...TROPICAL WAVES...
AXIS ALONG 88W FROM 02N-11N MOVING W AT 10 KT HAS LOST ITS 
PREVIOUS UPPER SUPPORT AND NOW ENCOUNTERS SLIGHT ADVERSE UPPER 
SHEAR FORCING ITS DECREASING CONVECTION S OF ITCZ E OF AXIS.  
WITH UPPER LEVEL RIDGE RECEDING E...WAVE SHOULD ENCOUNTER LESS 
ADVERSE ENVIRON WITHIN NEXT 36-48 HRS ENABLING CONVECTION TO 
REBUILD.  MODEL GUIDANCE STILL NOT FULLY SUPPORTIVE OF 
DEVELOPING WAVE...BUT MAINTAINS ITS PATH THROUGH NEXT 48 HRS. 
 
...ITCZ...
AXIS ALONG 07N77W TO 11N110W TO 05N133W TO 06N140W.  SCATTERED 
MODERATE ISOLATED STRONG WITHIN 180 NM OF AXIS E OF 103W. 
SCATTERED MODERATE WITHIN 30 NM OF AXIS FROM 132W-135W. 

.DISCUSSION...
WESTERLY ZONAL FLOW ALOFT INTERRUPTED BY WEAK TROUGH EXTENDING 
FROM 24N124W TO DEVELOPING CYCLONIC VORTEX AT 04N134W ALLOWING 
SOME MOISTURE TO PENETRATE THE OTHERWISE STEADY DRY AIR MASS 
THAT COVER E PAC N OF 18N W OF 100W.

WEAKENED MID/UPPER LEVEL RIDGE SUPPORTED BY VARIOUS ANTICYCLONIC 
GYRES NOW RECEDE E LEAVING SURFACE LOW PRES AT 11N123W WITHOUT 
SUPPORTIVE OUTFLOW DOOMING THE LOW PRES TO SLOW DEMISE WITHIN 
NEXT 24 HRS.  LOW PRES INFLUENCE IN CAUSING FRESH TRADES W OF 
130W DISSIPATES WITH IT.  ON THE OTHER HAND...EASTERNMOST LOW 
PRES 1008 MB STATIONARY AT 14N113W REMAINS UNDER GOOD DIFFLUENT 
OUTFLOW ENHANCED BY ANTICYCLONIC EDDY ALOFT AT 11N109W ENHANCING 
DEEP CONVECTION MOSTLY WITHIN 180 NM W OF AXIS OF ASSOCIATED 
TROUGH FROM 10N114W TO 16N112W.  RIDGE EXTENDS INTO NORTHWESTERN 
SECTIONS OF SOUTH AMERICA LETTING PLENTY OF TROPICAL MOISTURE 
INTO CARIBBEAN BASIN WHICH FLARES UP WITH DAYTIME HEATING MAINLY 
OVER ISLANDS...COLOMBIA AND CENTRAL AMERICA S OF HONDURAS.  

.ELSEWHERE AT THE SURFACE...
HIGH PRES CENTER 1030 MB WELL N OF AREA COMBINES WITH LOW PRES 
1010 MB OVER NORTHERN CALIFORNIA TO PRODUCE GALE FORCE N WINDS 
ALONG COASTAL WATERS WHICH EVENTUALLY CAUSES SWELL TRAINS TO  
ENCROACH INTO E PAC N OF 28N DURING NEXT 24 HRS. 

$$
WALLY BARNES