000
AXPZ20 KNHC 281629
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1445 UTC.

...SPECIAL FEATURE...
TROPICAL STORM ALETTA NEAR 15.5N 101.3W AT 1500 UTC IS 
STATIONARY.  ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB.  
MAXIMUM SUSTAINED WIND SPEED 40 GUSTS TO 50 KT.  SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC 
FOR MORE DETAILS.  STORM HAS BEEN MAINTAINING CLUSTER OF DEEP 
CONVECTION ON E SIDE WITH VERY COLD OVERSHOOTING TOPS.  UPPER 
LEVEL ENVIRONMENT REMAINS FAVORABLE FOR FURTHER SLOW 
INTENSIFICATION. 

...TROPICAL WAVES...
TROPICAL WAVE ALONG 92W FROM 2N TO 11N MOVE W 10 KT WITH 
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 120 NM W OF AXIS. 
BROAD AREA OF CYCLONIC CIRCULATION HAS SEVERAL WEAK SWIRLS 
ROAMING WITH NO APPARENT ORGANIZATION.  UPPER ENVIRONMENT STILL 
REMAINS NOT CONDUCIVE TO INTENSIFICATION BUT IS EXPECTED TO 
BECOME MORE FAVORABLE AS WAVE CONTINUES WESTWARD.  

..ITCZ...
ITCZ AXIS IS CENTERED ALONG...8N78W 7N81W 8N88W THEN 11N110W 
7N119W 6N130W 3N140W.  SCATTERED MODERATE STRONG CONVECTION FROM 
4N TO 10N E OF 85W.  NUMEROUS STRONG WITHIN 90 NM OF 8N118W.  
SCATTERED MODERATE ISOLATED STRONG WITHIN 90 NM OF AXIS W OF 
135W.

...DISCUSSION...
UPPER LEVEL FEATURES...
UPPER TROUGH DIGS SW FROM 32N117W TO 17N140W WITH VERY DRY 
AIRMASS WITHIN 240 NM NW OF AXIS.  MINOR ADVECTION OF MOISTURE N 
OF 26N W OF 130W.  SOUTH EXTENSION OF TROUGH CURTAILED BY WELL 
ANCHORED ANTICYCLONIC CIRCULATION CENTERED AT 10N117W WITH MID/ 
UPPER LEVEL RIDGE EXTENDING OVER T.S. ALETTA AND THEN FURTHER 
EAST TO 14N88W...JUST NORTH OF INCOMING TROPICAL WAVE.  FAIRLY 
DRY AIR BETWEEN TROUGH AND RIDGE BUT PLENTY OF MOISTURE SE OF 
RIDGE OVER ITCZ SPECIALLY E OF 100W.  UPPER FLOW APPEARS QUITE 
DIFFLUENT SE OF RIDGE W OF 95W WHICH COULD ENHANCE DEEP 
CONVECTION OF TROPICAL WAVE.  THIS SCENARIO SUGGESTED BY GFS 
WITHIN NEXT 36-48 HRS.   

SURFACE FEATURES...
E PAC RIDGE CENTER AT 30N140W 1025 MB CONTINUES TO WEAKEN 
THROUGH FORECAST PERIOD AND GRADUALLY DECREASE TRADES W OF 120W. 
SOUTHERLY WARM MOIST WINDS ACROSS EQUATOR BRING INGREDIENTS TO 
ITCZ FOR CONTINUATION OF DEEP CONVECTION AND GENERATE INCREASE 
IN WIND SPEEDS.  

WINDS ALONG BAJA CALIFORNIA COAST DECREASE AS HIGH PRES RIDGE 
WEAKENS.  MODERATE SWELLS LIKELY TO REMAIN N OF 25N. 

$$
WALLY BARNES