000
AXPZ20 KNHC 232154
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JUL 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 
2145 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE N OF 04N ALONG 92W HAS MOVED W AT LEAST 25 KT 
OVER THE PAST 48 HOURS. THE WAVE IS MOVING UNDER AN AREA OF 
UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER RIDGE THAT IS 
STATIONARY OVER THE TROPICAL PACIFIC E OF 103W. ASSOCIATED 
CONVECTION IS ISOLATED MODERATE AT BEST. 
   
A TROPICAL WAVE FROM 04N TO 14N ALONG 103W HAS MOVED W AT ABOUT 
19 KT OVER THE PAST 24 HOURS. CONVECTION IS FLARING WITHIN 150 
NM OF THE WAVE AXIS. THE WAVE IS STILL WITHIN AN AREA OF WEAK 
UPPER LEVEL DIFFLUENCE BUT WILL MOVE THROUGH AN AREA THAT IS 
UNFAVORABLE FOR CONVECTION ON THU AND FRI. 

A TROPICAL WAVE IS ANALYZED FROM 05N TO 14N AROUND 130W BUT IS 
BECOMING DIFFICULT TO LOCATE. THIS WAVE IS MOVING THROUGH AN 
AREA OF SOUTHWESTERLY UPPER SHEAR.

...ITCZ...
THE AXIS IS ALONG 08N77W TO 10N92W TO 06N113W TO 11N131W TO 
09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 150 NM EITHER SIDE OF LINE FROM 05N80W TO 12N104W AND 
ALSO WITHIN 180 NM OF A LINE FROM 15N122W TO 09N140W.  

...DISCUSSION...
AN UPPER LEVEL TROPICAL ANTICYCLONE IS CENTERED NEAR 09N135W 
WITH AN UPPER RIDGE EXTENDING E TO W OVER THE ITCZ BETWEEN 125W 
AND 141W. ITCZ CONVECTION IS ENHANCED BETWEEN 120W AND 150W. AN 
UPPER ANTICYCLONE IS CENTERED OVER EXTREME NORTHERN OLD MEXICO 
AT 31N110W WITH ITS ANTICYCLONIC ENVELOPE EXTENDING S OVER THE 
AREA N OF 26N BETWEEN 103W AND 117W. ANOTHER UPPER ANTICYCLONE 
IS CENTERED OVER THE SW CARIBBEAN HAS A RIDGE EXTENDING SW 
ACROSS CENTRAL AMERICA TO A CREST AT 10N106W AND HAS BEEN 
ENHANCING CONVECTION OVER THE TROPICAL E PACIFIC E OF 105W. SOME 
OF THE DEBRIS CIRRUS IS ADVECTED NE ACROSS CENTRAL AMERICA AND 
THE NW CARIBBEAN...AND SOME OF THE MOISTURE IS ADVECTED S BUT 
SEEMS TO EVAPORATE BEFORE IT REACHES THE EQUATOR.

A DEEP LAYERED CYCLONE IS CENTERED NEAR 32N146W WITH CYCLONIC 
FLOW DOMINATING THE UPPER LEVELS N OF 22N W OF 130W WHERE UPPER 
DEBRIS MOISTURE IS ALSO NOTED. A BAND OF DRY UPPER AIR IS NOTED 
WITHIN 120 NM EITHER SIDE OF POINTS 14N135W TO 20N123W TO 
28N120W. ANOTHER UPPER TROUGH EXTENDS ACROSS THE SOUTHERN GULF 
OF MEXICO AND ACROSS OLD MEXICO ALONG 20N100W INTO AN UPPER 
CYCLONE AT 11N108W WITH THE TROUGH CONTINUING S AND CROSSING THE 
EQUATOR AT 107W.  

GAP WINDS...NE TO E WINDS IN AND JUST DOWNSTREAM OF THE GULF OF 
PAPAGAYO WILL PULSE TO 20 KT OVER THE NEXT FEW DAYS.

LONG PERIOD SOUTHERLY SWELLS RESULTING IN MAX SEAS OF 8 TO 13 FT 
ARE CROSSING THE EQUATOR REACHING THE PACIFIC COAST OF CENTRAL 
AMERICA AND SHOULD REACH CENTRAL BAJA PENINSULA LATE FRI THEN 
BEGIN TO DIMINISH ON SAT.

$$
NELSON