000
AXPZ20 KNHC 300930
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI APR 30 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

AXIS ANALYZED FROM 11N86W TO 08N110W TO 05N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS FROM 02N TO 09N BETWEEN 
81W AND 99W...AND ALSO WITHIN 200 NM OF THE AXIS BETWEEN 102W 
AND 120W.

...DISCUSSION...

A LONGWAVE UPPER LEVEL TROUGH DOMINATES THE WESTERN CONUS WITH 
ITS MEAN AXIS EXTENDING FROM SOUTHERN UTAH OVER EXTREME SOUTHERN 
CALIFORNIA AND INTO THE DISCUSSION AREA ALONG 32N118W TO 
26N124W. UPPER LEVEL MOISTURE SPREADS SE INTO THE TROUGH OVER 
THE AREA N OF 30N BETWEEN 122W AND 140W. OTHERWISE THE UPPER 
LEVELS ARE DRY N OF POINTS 17N140W TO 23N120W TO 12N100W. THE 
LONGWAVE UPPER LEVEL TROUGH IS EXPECTED TO STRENGTHEN SLIGHTLY 
OVER THE BAJA PENINSULA AND NW MEXICO THROUGH EARLY SUNDAY THEN 
THE ASSOCIATED ENERGY IS FORECAST TO LIFT BACK N OF 30N OVER THE 
CENTRAL CONUS BY MONDAY. THIS LONGWAVE TROUGH WILL CONTINUE 
DRAGGING AN UPPER LEVEL TROUGH CURRENTLY ALONG 146W INTO THE 
DISCUSSION AREA BY LATE FRIDAY AND EASTWARD THROUGH THE WEEKEND 
INTO EARLY NEXT WEEK.

AN UPPER ANTICYCLONE IS STATIONARY OVER NICARAGUA NEAR 13N84W 
WITH AN UPPER LEVEL RIDGE EXTENDING W ACROSS THE TROPICAL 
PACIFIC ALONG 10N100W TO 10N140W. ITCZ CONVECTION IS ENHANCED 
UNDER THE UPPER LEVEL RIDGE E OF 120W. MOISTURE NOTED ON WATER 
VAPOR IMAGERY BETWEEN 120W AND 140W IS ADVECTED NE FROM THE ITCZ 
REGION...BUT LARGELY EVAPORATES BY THE TIME IT REACHES 20N120W 
IN THE DRY AIR ACCOMPANYING UPPER LEVEL CONFLUENCE ASSOCIATED 
WITH THE BASE OF THE UPPER LEVEL TROUGH PREVIOUSLY DESCRIBED. 
ITCZ CONVECTION REMAINS ENHANCED E OF 100W...AND IN THE AREA N 
OF 09N TO THE COAST OF SOUTHERN MEXICO BETWEEN 90W AND 96W. 

ELSEWHERE AT THE SURFACE...
A RIDGE IS NEARLY STATIONARY FROM 32N140W TO NEAR 12N112W. NE 
TRADES THE S OF THE RIDGE AXIS ARE AT 15 TO 20 KT AS DEPICTED ON 
A 30/0232 UTC WINDSAT PASS...WITH SEAS 8 TO 10 FT IN NEW NE 
TRADE WIND GENERATED SWELL MIXING WITH LONG PERIOD NW SWELL. 
NORTHERLY WINDS NE OF THE RIDGE AXIS REACH THE WESTERN BAJA 
PENINSULA IN 20 TO 30 KT RANGE AS OBSERVED BY A 30/0510 UTC 
ASCAT PASS AND ALSO 25 KT WINDS WERE REPORTED BY NOAA SHIP 
KA'IMIMOANA AS SHE SAILS NORTHWARD NEAR 29N119W. SEAS HEIGHTS 
ARE EXPECTED TO BUILD TO ABOUT 15 FT ALONG 29N NEAR 119W BY LATE 
FRIDAY. THESE NW SWELLS SHOULD IMPACT THE DEEP TROPICS BY THE 
WEEKEND WHERE THEY WILL MIX WITH A NEW SERIES OF LONG PERIOD SW 
SWELL CROSSING THE EQUATOR BY EARLY SUNDAY.
   
$$
HUFFMAN