000
AXPZ20 KNHC 280327
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN MAY 28 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 NEAR 15.7N 101.0W AT 0300 UTC. THIS IS  
ABOUT 110 MILES...180 KM...SOUTHWEST OF ACAPULCO MEXICO.
ALETTA IS NEARLY STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE 
IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 
45 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO 
STRONG WITHIN 150 NM  OVER E SEMICIRCLE. SCATTERED MODERATE 
ISOLATED STRONG ELSEWHERE WITHIN 30 NM EITHER SIDE OF LINE 
14.5N100W 12N105W. A LOW LEVEL SWIRL THAT RACED OFF TO THE W 
EARLIER IS LOSING IDENTITY AT THE MOMENT. IF ANOTHER LOW LEVEL 
CENTER OF CIRCULATION DOES NOT SOON DEVELOP TO THE E UNDER THE 
MAIN CONVECTION ALETTA WILL BE SHORT LIVED.

...TROPICAL WAVES...

A TROPICAL WAVE ALONG 90W N OF 2N HAS MOVED W 10 KT THE PAST 48 
HOURS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION NOTED 
FROM 3N TO 9N BETWEEN 88W AND 93W.

..ITCZ...

ITCZ AXIS IS CENTERED ALONG...8N83W 8N87W 14N104W 8N120W 6N140W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM EITHER SIDE OF 
LINE 5N81W 7N94W AND WITHIN 120 NM EITHER SIDE OF LINE 14N101W 
10N110W 7N118W. ISOLATED MODERATE WITHIN 30 NM OF LINE 10N127W 
6N140W.

...DISCUSSION...

AN UPPER CYCLONE OVER THE NW CONUS HAS A SHORTWAVE TROUGH 
EXTENDING SSE INTO THE DISCUSSION AREA ALONG 32N115W THROUGH 
ANOTHER CYCLONE ESTIMATED NEAR 25N111W TO A BASE AT 16N104W...
JUST NW OF THE TROPICAL STORM. DRY UPPER AIR IS INDICATED N OF 
20N W OF 120W MERGING WITH AN AREA NW OF A LINE FROM 9N120W 
18N101W. AT THE LOW LEVELS A RIDGE EXTENDS ALONG 30N140W TO 
15N110W WITH SCATTERED TO BROKEN STRATOCUMULUS N OF 14N W OF 
110W.

AN UPPER ANTICYCLONE IS CENTERED NEAR 9N117W WITH ITS ENVELOPE 
OF ANTICYCLONIC FLOW DOMINATING THE DISCUSSION AREA N OF THE 
ITCZ TO 23N BETWEEN 142W AND 105W. DEBRIS MOISTURE FROM ITCZ 
CONVECTION W OF 121W IS ADVECTED N BUT EVAPORATES ALONG 13N. 

AN UPPER ANTICYCLONE IS CENTERED OVER THE W CARIBBEAN NEAR 
15N83W WITH A RIDGE CREST SOMEWHAT ERODING ALONG POINTS 18N100W 
24N90W 26N76W. UPPER DEBRIS MOISTURE FROM ITCZ CONVECTION 
BETWEEN 103W AND 114W...AND CONVECTION ASSOCIATED WITH THE 
TROPICAL STORM IS ADVECTED ENE ALONG THE NW PERIPHERY OF THIS 
RIDGE...ROUGHLY WITHIN 240 NM EITHER SIDE OF POINTS 17N95W 
21N81W TO BEYOND 23N65W. UPPER DIFFLUENCE UNDER THE RIDGE IS 
ALSO ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 94W AND 77W BUT 
THE DEBRIS MOISTURE REMAINS IN ROUGHLY THE SAME AREA TO THE N 
BUT IS SPREADING S TO NEAR THE EQUATOR AT 90W. 

$$
NELSON