000
AXPZ20 KNHC 192134
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE MAY 19 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 
2100 UTC.

...ITCZ...
AXIS ALONG 08N83W TO 10N108W TO 12N117W TO 05N130W TO 05N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 210 NM OF 
AXIS E OF 123W.  ISOLATED MODERATE CONVECTION WITHIN 60 NM OF 
AXIS FROM 131W-135W.

...DISCUSSION...
LARGE AMPLITUDE MID/UPPER TROUGH EXTEND FROM CYCLONIC VORTEX AT 
32N122W TO 11N105W SPLITTING RIDGE ALOFT WHICH RUNS E-W WITH TWO 
ANTICYCLONES...ONE AT 11N122W AND ANOTHER AT 09N100W.  RIDGE 
ALLOWS PLENTY OF TROPICAL MOISTURE TO ENCROACH INTO E PAC ON ITS 
SOUTHER PERIPHERY ALONG ITCZ E OF 120W.  E PAC REMAINS VERY DRY 
W OF UPPER TROUGH WITH SOME CONVECTIVE DEBRIS MOISTURE MOVING NE 
INTO CENTRAL MEXICO E OF TROUGH AXIS.  WINDS ALOFT W OF 120W 
REMAIN MQUASI-ZONAL WITH
DUE W JET CORE OF 90 KT.  

WEAK SURFACE LOW PRES 1008 MB EMBEDDED IN ITCZ AT 11N122W HAS 
FAVORABLE UPPER ENVIRONMENT AND PLENTY OF LOW LEVEL MOISTURE BUT 
STILL LACK ANY ORGANIZED CIRCULATION AND MOVING INTO VERY DRY 
AND STABLE ZONE AHEAD.  CHANCES OF ITS DEVELOPMENT CONSIDERED  
AS VERY LOW.  

ELSEWHERE AT THE SURFACE...
WEAK HIGH PRES 1020 MB AT 28N126W HAS SURFACE RIDGE EXTEND TO 
18N110W.  HIGH PRES FORECAST TO MERGE WITH SECOND HIGH PRES 1032 
MB MOVING W INTO WATERS JUST N OF E PAC.  GALE FORCE WINDS ALONG 
CENTRAL CALIFORNIA COASTAL WATERS BUILD MODERATE N-NW SWELL 
SPREADING S JUST N OF 25N E OF 117W.
 
GAP WINDS...GULF OF TEHUANTEPEC GALE FORCE WIND EVENT SUBSIDED 
AS HIGH PRES FORCING N WINDS WEAKENS.  WINDS DIMINISH BUT STILL 
REMAIN CLOSE TO 30 KT NEXT 24 HRS AND TO LESS THAN 20 KT BY THU.

$$
WALLY BARNES