000
AXPZ20 KNHC 200302
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAY 20 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG AXIS 9N80W 6N84W 12N95W 8N110W 
7N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 180 NM OF AXIS 
BETWEEN 81W AND 130W.

...DISCUSSION...

A DEEP LAYERED CYCLONE IS N OF DISCUSSION AREA NEAR 40N134W WITH 
A TROUGH EXTENDING SW TO A BASE NEAR 22N138W. A SURFACE FRONT 
HAS WEAKENED TO A TROUGH LYING ALONG 32N126W 20N136W AND 
CONTINUES TO SHIFT E WITH TIME. DRY UPPER AIR IS NOTED WITHIN 
150 NM EITHER SIDE OF LINE 30N122W 25N140W. 

A BROAD UPPER ANTICYCLONE LIES ALONG 11N BETWEEN 125W AND 105W 
WITH A MEAN CENTER ESTIMATED NEAR 11N116W. AN UPPER RIDGE 
EXTENDS N THROUGH 26N118W THEN MERGES INTO A LONGWAVE RIDGE 
DOMINATING WESTERN N AMERICA ROUGHLY ALONG 110W. ASSOCIATED 
UPPER DIFFLUENCE ALONG E TO W RIDGE IS ENHANCING ITCZ CONVECTION 
BETWEEN 142W AND 105W. A PRONOUNCED BAND OF UPPER MOISTURE IS 
NOTED WITHIN 210 NM EITHER SIDE OF LINE 23N120W 15N140W. 
ELSEWHERE W OF 101W DEBRIS MOISTURE ORIGINATING FROM THE 
ENHANCED ITCZ CONVECTION SPREADS NE BUT SEEMS TO EVAPORATE 
IMMEDIATELY ALONG 12N TO 13N AS VERY DRY UPPER AIR IS INDICATED 
ELSEWHERE N OF THE ITCZ BETWEEN 123W AND 97W. 

THE SHORTWAVE RIDGE SEPARATES THE UPPER TROUGH OVER THE W 
PORTION FROM AN UPPER TROUGH THAT DOMINATES EASTERN N AMERICA 
AND EXTENDS SW INTO THE DISCUSSION AREA ALONG 32N82W 14N102W.
ANOTHER ILL-DEFINED ANTICYCLONE IS ESTIMATED NEAR 14N92W WITH 
ITS ASSOCIATED UPPER DIFFLUENCE ENHANCING THE ITCZ BETWEEN 101W 
AND 72W. THE RESULTANT DEBRIS MOISTURE IS ADVECTED NE ACROSS ALL 
OF CENTRAL AMERICA AND ACROSS THE CENTRAL CARIBBEAN.

$$
NELSON