000
AXPZ20 KNHC 230333
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAY 23 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 
0300 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTEND S FROM EASTERN COSTA RICA ALONG 84W TO 
02N.  MOST CONVECTION REMAINS OVER COASTAL WATERS N OF 05N E OF  
85W.  WAVE UNDER AREA OF DIFFLUENT FLOW ALOFT LIKELY TO DEVELOP 
MORE DEEP CONVECTION NEXT 12-18 HRS...BUT SHOULD ENCOUNTER 
ADVERSE UPPER CONDITIONS FURTHER W.  NO ORGANIZATION NOTED AT 
THIS TIME.

...ITCZ...
AXIS ALONG 07N78W TO 10N100W TO 06N128W TO 06N140W.  SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 180 NM N AND 300 NM S 
OF AXIS E OF 103W AND WITHIN 150 NM N OF AXIS FROM 128W-132W.

.DISCUSSION...
UPPER LEVEL RIDGE SPREADS ACROSS E PAC ALONG 10N-12N E OF 126W 
SUPPORTED BY SEVERAL ANTICYCLONES.  RIDGE ADVECTING ABUNDANT 
TROPICAL CONVECTION DEBRIS EASTWARD JUST ALONG ITCZ MAKING 
MOISTURE AVAILABLE TO ENHANCE MORE CONVECTION WHERE LOW LEVEL 
UPLIFTING IS FOUND.  THERE ARE TWO MAIN SOURCES OF UPLIFT...ONE 
IS LOW PRES CENTER 1008 MB AT 14N112W WITH SCATTERED MODERATE TO 
STRONG CONVECTION AND ANOTHER IS WITH TROPICAL WAVE AS DESCRIBED 
IN ITS SECTION ABOVE.

MOST OF E PAC UPPER LEVEL WINDS REMAIN QUASI-ZONAL N OF 19N 
WHERE WEAKENING 80 KT JET CORE KEEPS A DRY AIR UMBRELLA OVER 
REGION EXCEPT NEW SWATH OF MOISTURE ENTERING W SIDE OF BASIN 
AHEAD OF UPPER LEVEL TROUGH STILL W OF 140W.

.AT THE SURFACE...HIGH PRES CENTER 1030 MB WELL N OF REGION HAS 
RIDGE EXTEND SE TO 21N113W.  SYSTEM PRODUCING N GALE FORCE WINDS 
ALONG COAST OF CALIFORNIA.  SWELL TRAINS BUILT BY GALE 
EVENTUALLY FIND THEIR WAY INTO E PAC N OF 27N FROM 120W-137W.

WEAK LOW PRES AT 12N122W ENHANCES FRESH NE TRADES WITH 8 FT SEAS 
FROM 10N-19N BETWEEN 125W-135W.  LOW PRES WEAKENS WITHIN 18 HRS 
AND TRADES DIMINISH BELOW 20 KT.  SECOND LOW PRES CENTER AT 
14N112W SITS UNDER ONE OF ANTICYCLONES WITH GOOD DIFFLUENT FLOW 
ALOFT ENHANCING DEEP CONVECTION FROM 12N-15N BETWEEN 112W-115W.
MODEL GUIDANCE STRENGTHENS THIS SYSTEM AS IT MOVES AWAY FROM 
ITCZ INFLUENCE WITH STRONG WINDS WITHIN 180 NM OF CENTER THROUGH 
NEXT 48 HRS. 

$$
WALLY BARNES