000
AXPZ20 KNHC 290317
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAY 29 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 STORM ALETTA IS ESTIMATED NEAR 16.0N 101.0W AT 0300 
UTC. THIS POSITION IS ABOUT 95 MILES...155 KM...SOUTHWEST OF 
ACAPULCO MEXICO. ALETTA IS DRIFTING SLOWLY N AT 2 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND 
SPEED IS 40 KT WITH GUSTS TO 50 KT. NUMEROUS STRONG CONVECTION 
WITHIN 75 NM N SEMICIRCLE AND 110 NM S SEMICIRCLE. STRONG W 
SHEAR IS CONTINUING TO SUPPRESS CONVECTION OVER THE W 
SEMICIRCLE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 

...TROPICAL WAVES...

A TROPICAL WAVE ALONG 94W N OF 2N HAS MOVED W 10 KT THE PAST OF 
DAYS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION NOTED 
WITHIN 30 NM OF THE WAVE AXIS AT 7N.

..ITCZ...

ITCZ AXIS IS CENTERED ALONG...10N85W 10N96W 14N105W 7N121W 
4N140W. SCATTERED MODERATE TO STRONG NE OF LINE 4N77W 7N80W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 60 NM EITHER SIDE OF 
LINE 3N88W 9N97W AND WITHIN 120 NM EITHER SIDE OF LINE 12N104W 
14N111W 8N116W AND WITHIN 90 NM EITHER SIDE OF LINE 6N128W 
5N140W.

...DISCUSSION...

AN UPPER CYCLONE IS NEARLY STATIONARY OVER THE NW CONUS. A  
NEGATIVE TILT SHORTWAVE TROUGH EXTENDS SSE INTO THE DISCUSSION 
AREA ALONG 32N114W TO A BASE OVER COASTAL OLD MEXICO AT 
21N104W...JUST NW OF THE TROPICAL STORM. DRY UPPER AIR IS 
INDICATED WITHIN A 300 NM WIDE BAND DEFINED BY POINTS 17N150W 
23N135W 30N103W. ANOTHER BAND OF DRY AIR IS INDICATED WITHIN 180 
NM EITHER SIDE OF LINE 9N128W 20N110W WHERE IT MERGES WITH THE 
PREVIOUSLY DESCRIBED DRY AREA. AT THE LOW LEVELS A RIDGE EXTENDS 
ALONG 32N138W TO 13N115W WITH SCATTERED TO BROKEN STRATOCUMULUS 
N OF 12N W OF 118W.

AN UPPER ANTICYCLONE IS QUASI STATIONARY NEAR 11N114W WITH ITS 
ENVELOPE OF ANTICYCLONIC FLOW DOMINATING THE DISCUSSION AREA N 
OF THE ITCZ TO 22N BETWEEN 140W AND 110W MERGING WITH THE FLOW 
ASSOCIATED WITH ANOTHER ANTICYCLONE NEAR 12N106W...WITH ITS 
RIDGE IN TURN EXTENDING E TO A CREST AT 12N88W. DEBRIS MOISTURE 
FROM ITCZ CONVECTION W OF 134W IS ADVECTED NE AND REMAINS UNDER 
THE RIDGE ALONG LINE 12N135W 20N120W. UPPER DIFFLUENCE UNDER THE 
RIDGE TO THE E OF 120W IS ENHANCING CONVECTION ALONG THE ITCZ 
BETWEEN 120W AND 104W...BUT THE DEBRIS MOISTURE REMAINS UNDER 
THE UPPER RIDGE. A RIDGE ALSO EXTENDS NE FROM THE ANTICYCLONE AT 
12N106W ACROSS THE TROPICAL STORM CRESTING OVER THE GULF OF 
MEXICO ALONG POINTS 27N97W 23N84W.

AN UPPER ANTICYCLONE IS CENTERED OVER S AMERICA AT 8S71W WITH A 
RIDGE EXTENDING NW ACROSS THE EQUATOR TO A CREST ALONG 16N81W 
10N92W. UPPER DIFFLUENCE UNDER THE RIDGE IS ALSO ENHANCING 
CONVECTION ALONG THE ITCZ BETWEEN 98W AND 71W WITH THE DEBRIS 
MOISTURE SPREADING S EVENTUALLY EVAPORATING ALONG THE EQUATOR 
BETWEEN 82W AND 105W. 

$$
NELSON