000
AXPZ20 KNHC 300321
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE MAY 30 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.

...SPECIAL FEATURE...

TROPICAL DEPRESSION ALETTA IS ESTIMATED NEAR 16.0N 102.3W AT 
0300 UTC. THIS POSITION IS ABOUT 120 MILES...195 KM...SOUTH OF 
ZIHUATANEJO MEXICO. ALETTA IS MOVING W AT 4 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND 
SPEED IS 30 KT WITH GUSTS TO 40 KT. ONLY SMALL CLUSTERS OF 
CONVECTION HAVE BEEN FLARING OVER THE N QUADRANT AND ALETTA IS 
WEAKENING RAPIDLY. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 

...TROPICAL WAVES...

A TROPICAL WAVE ALONG 98W N OF 2N HAS MOVED W 10 KT THE PAST OF 
DAYS. SCATTERED MODERATE CONVECTION NOTED WITHIN 60 NM OF THE 
WAVE AXIS FROM 4N TO 11N.

..ITCZ...

ITCZ AXIS IS CENTERED ALONG...AXIS ALONG 9N84W 9N98W 13N113W 
7N125W 6N140W. ISOLATED MODERATE TO STRONG FROM 5N TO 11N 
BETWEEN 81W AND 101W. SCATTERED MODERATE ISOLATED STRONG WITHIN 
90 NM EITHER SIDE OF LINE 14N11W 7N126W AND LINE 7N134W 8N140W.

...DISCUSSION...

A SLIGHTLY NEGATIVE TILT SHORTWAVE TROUGH EXTENDS SSE INTO THE 
DISCUSSION AREA ALONG 32N110W TO ANOTHER UPPER CYCLONE NEAR 
24N96W. AN ILL-DEFINE UPPER ANTICYCLONE IS NEAR 27N134W AND A 
WELL DEFINED ANTICYCLONE IS AT 14N111W WITH A RIDGE EXTENDING SW 
TO BEYOND 8N140W. A RIDGE ALSO EXTENDS NE TO A CREST NEAR 
23N101W. 

DRY UPPER AIR IS INDICATED WITHIN A 300 NM WIDE BAND WITH AXIS 
ALONG POINTS 16N148W 23N130W 24N100W. ANOTHER AREA OF DRY AIR IS 
INDICATED WITHIN 180 NM EITHER SIDE OF LINE 11N125W 20N111W AND 
YET ANOTHER IS WITHIN 120 NM EITHER SIDE OF LINE 13N106W 
20N103W. DEBRIS MOISTURE FROM ITCZ CONVECTION W OF 132W IS 
ADVECTED NE AND REMAINS UNDER THE RIDGE WITHIN 150 NM EITHER 
SIDE OF LINE 9N136W 18N121W. UPPER DIFFLUENCE BENEATH THE RIDGE 
TO THE E OF 120W IS ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 
120W AND 110W...BUT THE DEBRIS MOISTURE REMAINS UNDER THE UPPER 
RIDGE. 

AT THE LOW LEVELS A HIGH PRES IS AT 32N137W 1026 MB WITH A RIDGE 
EXTENDING SE TO 12N107W. SCATTERED TO BROKEN STRATOCUMULUS IS 
OBSERVED SW OF LINE 32N123W 16N109W. 

AN UPPER ANTICYCLONE IS CENTERED OVER S AMERICA AT 9S71W WITH A 
RIDGE EXTENDING NW ACROSS THE EQUATOR TO A SHARP CREST AT 
11N96W. UPPER DIFFLUENCE UNDER THIS RIDGE IS ENHANCING 
CONVECTION ALONG THE ITCZ E OF 98W WITH THE DEBRIS MOISTURE 
OBSERVED FROM 2N TO 12N BETWEEN 98W AND 70W. 

$$
NELSON