000
AXPZ20 KNHC 250316
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JUL 25 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...
A TROPICAL WAVE IS N OF 05N ALONG 90W AND HAS MOVED W AT ABOUT 
23 KT OVER THE PAST 24 HOURS. CONVECTION IS ENHANCED WITHIN 120 
NM W OF THE AXIS TO THE S OF 08N.
 
A TROPICAL WAVE TO THE N OF 04N ALONG 104W HAS MOVED W AROUND 25 
KT OVER THE PAST FEW DAYS. THE WAVE IS MOVING UNDER THE W 
PERIPHERY OF AN UPPER RIDGE WITH THE ASSOCIATED DIFFLUENCE 
ENHANCING CONVECTION FROM 06N TO 16N WITHIN 120 NM OF THE WAVE 
AXIS.
   
A TROPICAL WAVE EXTENDS FROM 04N TO 14N ALONG 112W AND HAS MOVED 
W AT ABOUT 20 KT OVER THE PAST 48 HOURS. THE WAVE IS MOVING 
THROUGH AN AREA OF UNFAVORABLE UPPER SUPPORT AND CONVECTION IS S 
SUPPRESSED N OF 10N WITH ONLY A FEW CLUSTERS NOTED ALONG THE 
WAVE TO THE S OF 10N.

A TROPICAL WAVE IS ANALYZED FROM 08N TO 14N AROUND 136W BUT IS 
DIFFICULT TO LOCATE. THIS WAVE IS MOVING THROUGH AN AREA OF 
WESTERLY UPPER SHEAR THAT IS STRETCHING CONVECTION WELL TO THE E 
OF THE ESTIMATED SURFACE LOCATION.

...ITCZ...
THE AXIS IS NOTED ALONG POINTS FROM 07N77W TO 10N103W TO 07N113W 
TO 12N135W TO 11N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 180 NM EITHER SIDE OF LINE FROM 
07N77W TO 06N92W TO 14N107W TO 07N117W...AND ALSO WITHIN 60 NM 
OF A LINE FROM 11N127W TO 14N130W TO 12N137W. 

...DISCUSSION...
AN UPPER LEVEL TROPICAL ANTICYCLONE IS CENTERED NEAR 11N137W 
WITH AN UPPER RIDGE EXTENDING E AND W OVER THE ITCZ BETWEEN 124W 
AND 149W. THE DEBRIS MOISTURE SEEMS TO REMAIN WITHIN RIDGE 
ENVELOPE...ROUGHLY FROM 06N TO 15N. AN UPPER ANTICYCLONE IS 
CENTERED OVER THE NEW MEXICO AND ARIZONA BORDER NEAR 33N110W 
WITH A RIDGE EXTENDING SE TO RIDGE CREST OVER OLD MEXICO AT 
25N101W. ANOTHER UPPER ANTICYCLONE IS CENTERED OVER SOUTHERN OLD 
MEXICO NEAR 18N98W WITH ITS ASSOCIATED UPPER DIFFLUENCE 
ENHANCING CONVECTION OVER THE TROPICAL E PACIFIC BETWEEN 110W 
AND 77W...WITH THE RESULTANT DEBRIS MOISTURE BASICALLY REMAINING 
UNDER THE UPPER RIDGE.

A MID TO UPPER LEVEL CYCLONE IS CENTERED NEAR 33N142W WITH ITS 
CYCLONIC FLOW DOMINATING THE UPPER LEVELS N OF 21N W OF 130W 
WHERE UPPER DEBRIS MOISTURE IS ALSO NOTED. A NARROWING BAND OF 
DRY UPPER AIR IS NOTED N OF 13N BETWEEN 120W AND 125W. ANOTHER 
UPPER TROUGH IS WEAKENING OVER THE TROPICS S OF 18N ALONG 113W.

GAP WINDS...NE TO E WINDS IN AND DOWNSTREAM OF THE GULF OF 
PAPAGAYO WILL PULSE TO 20 KT THROUGH SAT...THEN INCREASE TO 20 
TO 25 KT SUN. NE WINDS AT 20 TO 25 KT ARE SURGING THROUGH THE 
GULF OF TEHUANTEPEC AND ARE EXPECTED TO CONTINUE THROUGH SAT 
THEN DIMINISH. SOUTHERLY SWELLS ARE MIXING WITH THESE GAPS 
WINDS. 

THE LONG PERIOD SOUTHERLY SWELLS RESULTING IN SEAS TO AT LEAST 8 
FT ARE OBSERVED S OF A LINE FROM 00N140W TO 22N110W EXTENDING E 
ALONG THE COAST OF CENTRAL AMERICA TO 83W. THESE SWELLS ARE 
BEGINNING TO SUBSIDE AND ARE EXPECTED ONLY BE OF CONCERN S OF 
12N BETWEEN 125W AND 90W BY LATE SUN.

$$
NELSON