000
AXPZ20 KNHC 061555
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAY 06 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...

ITCZ AXIS EXTENDS ALONG 04N77W TO 03N97W TO 08N110W TO 04N130W 
TO 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
NOTED FROM 05N TO 01S E OF 80W...AND IN A CLUSTER WITHIN 90 NM 
OF 11N109W...AND ALSO WITHIN 90 NM EITHER SIDE OF A LINE FROM 
03N120W TO 04N132W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS SW ALONG 32N121W INTO AN UPPER CYCLONE 
NEAR 21N138W. IMMEDIATELY SE AN UPPER SHORTWAVE RIDGE EXTENDS 
ALONG 10N140W TO A SHARP CREST AT 26N120W. UPPER MOISTURE IS 
SPREADING NE OVER THE AREA UNDER THE RIDGE...ROUGHLY WITHIN 210 
NM EITHER SIDE OF LINE 25N120W TO 17N135W. OTHERWISE THE UPPER 
LEVELS ARE DRY NW OF LINE 32N113W TO 24N130W TO 15N140W. ITCZ 
CONVECTION IS ALSO ENHANCED UNDER THE SHORTWAVE RIDGE...BETWEEN 
120W AND 140W. THE DEBRIS MOISTURE FROM THIS CONVECTION MERGES 
WITH ADDITIONAL MOISTURE ADVECTED E INTO THE AREA ALONG A 
TROPICAL JET...WITHIN 120 NM LINE 10N140W TO 05N130W.

AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER OLD MEXICO NEAR 
18N101W. A BROAD RIDGE COVERS THE UPPER LEVELS N OF THE ITCZ 
BETWEEN 116W AND 90W. SOME UPPER MOISTURE IS SPREADING NE ALONG 
THE NW PERIPHERY OF THIS RIDGE...ROUGHLY WITHIN 180 NM OF A LINE 
FROM 23N113W TO 32N100W TO 32N90W. ITCZ CONVECTION IS ENHANCED 
ALONG 10N BETWEEN 107W AND 119W...WITH UPPER CLOUD MOTIONS  
INDICATING AN UPPER TROUGH IS DEVELOPING FROM 11N114W TO 
02N122W. THE DEBRIS MOISTURE FROM THIS CONVECTION QUICKLY 
EVAPORATES IN THE DRY UPPER AIR UNDER THE RIDGE WHICH IS 
COVERING THE AREA S OF 26N BETWEEN 84W AND 113W.  

AN UPPER SHORTWAVE TROUGH EXTENDS S OVER THE NW CARIBBEAN AND 
CENTRAL AMERICA TO A BASE OVER THE E PACIFIC NEAR 04N83W. 
CONVECTION ALONG THE ITCZ IS SLIGHTLY ENHANCED ALONG THE BASE OF 
THE TROUGH...ROUGHLY ALONG 04N BETWEEN 90W AND 80W...AND OVER 
THE SW CARIBBEAN NEAR 11N79W. AN UPPER RIDGE CRESTING ALONG THE 
W COAST OF S AMERICA IS ENHANCING CONVECTION OVER COASTAL 
COLOMBIA AS PREVIOUSLY DESCRIBED. 

AT THE SURFACE...A BROAD RIDGE AXIS DOMINATES MOST OF THE 
DISCUSSION AREA WITH ITS AXIS MEANDERING FROM 32N135W TO 
15N105W. NE TRADES IN THE 15 TO 20 KT RANGE ARE SW OF THE RIDGE 
AXIS FROM 05N TO 23N W OF 130W. TO THE NE OF THE RIDGE... 
NORTHERLY WINDS IN THE 20 KT RANGE ARE OCCURRING ELSEWHERE N OF 
20N W OF 120W. THE ASSOCIATED NE SWELLS ARE MIXING WITH CROSS 
EQUATORIAL SW SWELL OVER MOST OF THE WATERS E 130W. 

A LOW LEVEL TROUGH IS ANALYZED THIS MORNING FROM 08N112W TO 
12N109W...AND IS A REFLECTION OF THE UPPER TROUGH MENTIONED 
ABOVE.  

GAP WINDS...NE-E WINDS OF 20 KT ARE EXPECTED TO SURGE INTO THE 
GULF OF PAPAGAYO BEGINNING LATE TONIGHT THEN PERSIST THROUGH AT 
LEAST 48 HOURS.

$$
NELSON