000
AXPZ20 KNHC 300336
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI APR 30 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...ITCZ...

AXIS ANALYZED FROM 10N85W TO 05N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS NOTED FROM 04N TO 10N BETWEEN 82W 
AND 105W...AND ALSO WITHIN 90 NM EITHER SIDE OF A LINE FROM  
08N98W TO 06N118W.

...DISCUSSION...

A LONGWAVE UPPER TROUGH DOMINATES THE WESTERN CONUS WITH ITS 
MEAN AXIS EXTENDING INTO THE DISCUSSION AREA ALONG 32N111W TO 
18N1093W. UPPER MOISTURE IS NOW SPREADING SE INTO THE TROUGH 
OVER THE AREA N OF 30N BETWEEN 128W AND 140W. OTHERWISE THE 
UPPER LEVELS ARE DRY N OF POINTS 16N140W TO 22N129W TO 12N100W. 
THE LONGWAVE IS EXPECTED TO CONTINUE THROUGH THE WEEKEND 
AMPLIFYING S TO OVER THE TROPICS EARLY NEXT WEEK. 

AN UPPER ANTICYCLONE IS STATIONARY NEAR 11N78W WITH AN UPPER 
RIDGE EXTENDING W ACROSS THE TROPICAL PACIFIC ALONG 10N120W TO 
09N140W. ITCZ CONVECTION HAS BEEN ENHANCED UNDER THE ENTIRE 
UPPER RIDGE. THE RESULTANT DEBRIS MOISTURE FROM CONVECTION 
BETWEEN 120W AND 140W IS ADVECTED NE...BUT FOR THE MOST PART 
EVAPORATES COMPLETELY BY THE TIME IT REACHES 21N125W IN THE DRY 
AIR ACCOMPANYING UPPER TROUGH PREVIOUSLY DESCRIBED. ITCZ 
CONVECTION IS ALSO ENHANCED E OF 100W...AND IN THE AREA N OF 10N 
TO THE COAST CENTRAL AMERICA BETWEEN 92W AND 96W. ALTHOUGH SOME 
OF THE DEBRIS MOISTURE FROM THESE AREAS IS ADVECTED S OF THE 
EQUATOR E OF 107W...MOST OF THE DEBRIS MOISTURE IS ADVECTED NE 
IN A PLUME THAT COVERS THE W CARIBBEAN...AND THEN TURNS E ACROSS 
THE SOUTHERN GULF OF MEXICO...S FLORIDA AND ACROSS ALL OF THE 
BAHAMAS. 

ELSEWHERE AT THE SURFACE...
A RIDGE IS BECOMING STATIONARY FROM 32N140W TO NEAR 12N110W. NE 
TRADES THE S OF THE RIDGE AXIS ARE AT 15 TO 20 KT...WITH SEAS 8 
TO 11 FT IN NEW NE TRADE WIND GENERATED SWELL MIXING WITH LONG 
PERIOD NW SWELL. NORTHERLY WINDS TO THE NE OF THE RIDGE REACH 
THE WESTERN BAJA PENINSULA IN 15 TO 25 KT RANGE WITH SEAS 
HEIGHTS EXPECTED TO BUILD TO ABOUT 17 FT ALONG 29N NEAR 118W BY 
LATE FRI. THESE NW SWELLS SHOULD REACH THE DEEP TROPICS BY THE 
WEEKEND WHERE THEY WILL MIX WITH A NEW SERIES OF LONG PERIOD SW 
SWELL CROSSING THE EQUATOR BY LATE SAT. THE SOUTHERLY MONSOON 
FLOW OVER THE FAR SE WATERS HAS DIMINISHED BELOW 20 KT AND SEAS 
HAVE ALSO SUBSIDED TO ABOUT 7 FT. 
   
$$
NELSON