000
AXPZ20 KNHC 220348
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JUL 22 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 
0315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE N OF 04N ALONG 89W HAS MOVED W AT 20 KT OVER THE 
PAST 24 HOURS AND HAS AVERAGED ABOUT 17 KT OVER THE PAST COUPLE 
OF DAYS. THE WAVE IS PROGRESSING WESTWARD UNDER A LARGE AREA OF 
UPPER LEVEL DIFFLUENCE THAT IS ENHANCING CONVECTION WITHIN A FEW 
HUNDRED MILES W OF THE WAVE AXIS.

TROPICAL WAVE FROM 05N TO 14N IS RELOCATED TO ALONG 124W.
THIS WAVE IS ALSO SITUATED UNDER AN AREA OF DIFFLUENCE THAT 
ENHANCED DEEP CONVECTION EARLIER WITH THE DEBRIS MOISTURE 
FANNING OUT OVER THE AREA FROM 03N TO 20N BETWEEN 114W AND 127W. 
BROAD LOW TO MID LEVEL CYCLONIC TURNING IS NOTED ALONG THE WAVE 
AXIS FROM 09N TO 12N. 
 
...ITCZ...
THE AXIS MEANDERS FROM 08N TO 10N FROM THE PANAMA TO 140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 04N 
TO 12N BETWEEN 86W AND 140W WITH THE MOST CONCENTRATED CLUSTERS 
SURROUNDING THE TWO TROPICAL WAVES.

...DISCUSSION...
THE UPPER LEVEL PATTERN IS SOMEWHAT COMPLEX OVER THE AREA W OF 
110W. AN UPPER RIDGE EXTENDS W TO E INTO THE DISCUSSION AREA 
ALONG 17N148W TO 18N134W AND IS ACCOMPANIED BY UPPER DEBRIS 
MOISTURE THAT ORIGINATES FROM ITCZ CONVECTION IN THE CENTRAL 
PACIFIC. AN UPPER LEVEL TROPICAL ANTICYCLONE IS CENTERED NEAR 
12N117W. AS MENTIONED ABOVE...ITS ASSOCIATED UPPER DIFFLUENCE 
HAS BEEN ENHANCING ITCZ CONVECTION BETWEEN 114W AND 134W. AN 
UPPER ANTICYCLONE CENTERED OVER SW ARIZONA HAS ITS ANTICYCLONIC 
ENVELOPE EXTENDING S OVER THE AREA N OF 26N BETWEEN 105W AND 
116W. ANOTHER UPPER ANTICYCLONE CENTERED OVER THE SW CARIBBEAN 
HAS A RIDGE EXTENDING SW ACROSS CENTRAL AMERICA AND OVER THE 
DEEP TROPICAL PACIFIC TO A RIDGE CREST AT 11N91W. CONVECTION 
ALONG THE E PACIFIC ITCZ IS ENHANCED E OF 105W WITH SOME OF THE 
DEBRIS CIRRUS ADVECTED NE ACROSS CENTRAL AMERICA...AND SOME 
MOISTURE ADVECTED S ACROSS THE EQUATOR BETWEEN 84W AND 97W.

SEPARATING THESE UPPER RIDGES IS A SERIES OF SHORTWAVE TROUGHS. 
THE WESTERNMOST TROUGH EXTENDS FROM SW CANADA TO 32N135W TO 
35N141W AND IS ACCOMPANIED BY A 120 NM WIDE BAND OF DRY UPPER 
AIR WHICH HAS SHIFTED SE OVER THE EXTREME NW PORTION. AN UPPER 
CYCLONE IS CENTERED NEAR 27N124W WITH A TROUGH EXTENDING SW TO 
18N128W. UPPER MOISTURE IS INDICATED N OF 25N BETWEEN 110W AND 
138W. ANOTHER UPPER TROUGH EXTENDS S ALONG THE E COAST OF THE 
UNITED STATES TURNING SW DISSECTING THE GULF OF MEXICO AND OVER 
THE E PACIFIC ALONG 18N94W TO 10N101W. 

GAP WINDS...NE TO E WINDS IN THE GULF OF PAPAGAYO AND JUST 
DOWNSTREAM WILL PULSE TO 20 KT OVER THE NEXT 30 HOURS OR SO THE 
DIMINISH BELOW 20 KT. 

LONG PERIOD SOUTHERLY SWELLS OF 18 TO 20 SECONDS RESULTING IN 
MAX SEAS OF 8 TO 13 FT ARE CROSSING THE EQUATOR AND ARE FORECAST 
TO MOVE THROUGH THE TROPICAL E PACIFIC REACHING THE PACIFIC 
COAST OF CENTRAL AMERICA LATE THU.

$$
NELSON