000
AXPZ20 KNHC 272229
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAY 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...SPECIAL FEATURE...

TROPICAL STORM ALETTA NEAR 15.6N 100.5W AT 2100 UTC. THIS IS  
ABOUT 100 MILES...160 KM...SOUTH-SOUTHWEST OF ACAPULCO MEXICO 
AND ABOUT 135 MILES...220 KM...WEST-SOUTHWEST OF PUNTA MALDONADO 
MEXICO. ALETTA IS DRIFTING NE AT 3 KT. 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 90 NM OVER NE QUADRANT. 
SCATTERED MODERATE ISOLATED STRONG ELSEWHERE WITHIN 110 NM 
EITHER SIDE OF LINE 16N98W 12N102W. A LOW LEVEL SWIRL IS RACING 
OFF TO THE W AT THE MOMENT JUST AS OCCURRED YESTERDAY WITH THE
EXCEPTION OF CONVECTION IS MUCH MORE CONCENTRATED. 

...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 
WITH 30 NM OF AXIS AT 7N. MORE IMPRESSIVE CONVECTION IS NOTED 
OVER COSTA RICA.

..ITCZ...

ITCZ AXIS IS CENTERED ALONG...AXIS 7N78W 9N90W. SECOND AXIS 
13N103W 8N123W 6N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 
90 NM EITHER SIDE OF LINE 5N83W 8N92W AND WITHIN 120 NM EITHER 
SIDE OF LINE 12N102W 8N114W AND WITHIN 30 NM OF 6N134W.

...DISCUSSION...

AN UPPER CYCLONE IS MOVING ONSHORE THE OREGON COAST WITH A 
SHORTWAVE TROUGH EXTENDED SSE INTO THE DISCUSSION AREA ALONG 
32N116W THROUGH ANOTHER CYCLONE ESTIMATED NEAR 24N111W TO A BASE 
AT 18N104W NEAR THE TROPICAL STORM. DRY UPPER AIR IS INDICATED N 
OF 20N W OF 120W MERGING WITH AN AREA NW OF A LINE FROM 9N120W 
20N100W. AT THE LOW LEVELS A RIDGE EXTENDS ALONG 32N142W TO 
15N115W WITH SCATTERED TO BROKEN STRATOCUMULUS N OF 14N W OF 
110W.

AN UPPER ANTICYCLONE IS CENTERED NEAR 10N119W WITH ITS ENVELOPE 
OF ANTICYCLONIC FLOW DOMINATING THE DISCUSSION AREA N OF THE 
ITCZ TO 23N BETWEEN 142W AND 112W. DEBRIS MOISTURE FROM ITCZ 
CONVECTION W OF 121W IS ADVECTED N BUT EVAPORATES ALONG 12N. 

AN UPPER ANTICYCLONE IS CENTERED OVER THE W CARIBBEAN NEAR 
15N85W WITH A RIDGE CREST SOMEWHAT ERODING ALONG POINTS 17N101W 
21N90W 28N79W. UPPER DEBRIS MOISTURE FROM ITCZ CONVECTION 
BETWEEN 103W AND 115W...AND CONVECTION ASSOCIATED WITH THE 
TROPICAL STORM IS ADVECTED NE ALONG THE NW PERIPHERY OF THIS 
RIDGE... ROUGHLY WITHIN 240 NM EITHER SIDE OF POINTS 15N96W 
21N83W TO BEYOND 23N65W. UPPER DIFFLUENCE UNDER THE RIDGE IS 
ALSO ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 92W AND 77W BUT 
THE DEBRIS MOISTURE REMAINS IN ROUGHLY THE SAME AREA. 

$$
NELSON