000
AXPZ20 KNHC 292121
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE APR 29 2008

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...
ITCZ AXIS IS ALONG THE LINE...06N77W TO 05N95W TO 08N110W TO 
06N130W TO 03N140W. SCATTERED MODERATE CONVECTION IS WITHIN 180 
NM EITHER SIDE OF AXIS BETWEEN 81W AND 94W. SCATTERED MODERATE 
AND EMBEDDED ISOLATED STRONG CONVECTION IS WITHIN 180 NM N AND 
90 NM S OF AXIS BETWEEN 115W AND 131W.

...DISCUSSION...

E OF 110W...
GALE CONDITIONS HAVE ENDED IN THE GULF OF TEHUANTEPEC AS NOTED 
IN A 1620 UTC HI-RES ASCAT WHICH SHOWED HIGHEST N WINDS NEAR 25 
KT. SHIP DHEP RECENTLY REPORTED NE WINDS OF 28 KT AND SEAS OF 10 
FT JUST OUTSIDE THE CORE OF THE GAP...SO PUT WORDING OF 20-30 KT 
IN THE HSFEP2. THESE WINDS WILL CONTINUE TO DIMINISH BECOMING 
LIGHT BY TOMORROW NIGHT AS THE HIGH PRES SYSTEM IN THE GULF OF 
MEXICO SHIFTS E INTO THE ATLC ALLOWING RETURN FLOW TO DEVELOP 
OVER THE W HALF OF THE GULF OF MEXICO. EARLIER SCATTEROMETER AND 
SHIP DATA HAVE ALSO SHOWED NE TO E 20-25 KT WINDS IN THE GULF OF 
PAPAGAYO. THIS GAP EVENT IS NOT OF THE TYPICAL ORIGIN BECAUSE 
THE CARIBBEAN TRADE WIND FLOW IS FAIRLY RELAXED. THE LIKELY 
TRIGGER IS WEAK CYCLONIC TURNING NOTED WEST OF COSTA 
RICA...NOTED IN QSCAT DATA. ALOFT...A PAIR OF MID-UPPER HIGHS 
LIE OVER THE REGION. THE MAIN HIGH CENTER IS OVER N VENEZUELA 
AND A SMALLER ONE CENTERED NEAR 8N98W. A DIFFLUENT PATTERN 
BETWEEN THESE SYSTEMS IS ENHANCING CONVECTION WITHIN THE ITCZ 
BETWEEN 81W-94W. MEANWHILE WAVE MODELS SHOW 18 SECOND SWELL UP 
TO SIX FEET OUT OF THE SOUTHWEST MOVING TOWARD THE MEXICAN AND 
CENTRAL AMERICAN PACIFIC COASTS BY LATE WED.

W OF 110W...
AN UPPER TROUGH EXTENDING FROM BRITISH COLUMBIA TO 29N137W IS 
SHIFTING EASTWARD TOWARD THE CALIFORNIA COAST...FLATTENING OUT 
AN UPPER RIDGE N OF 20N. A 1034 MB SURFACE HIGH NEAR 37N146W IS 
ALSO BUILDING EASTWARD BEHIND THE UPPER TROUGH...MAINTAINING 
STRONG NORTHERLY FLOW AND ASSOCIATED SWELL ON ITS EASTERN 
PERIPHERY ALONG THE CALIFORNIA COAST...REACHING AS FAR SOUTH AS 
THE NORTHERN BAJA COAST THROUGH 48 HOURS. FRESH TRADES WILL ALSO 
PERSIST OVER THE NEXT COUPLE OF DAYS ON THE SOUTHERN PERIPHERY 
OF THE SURFACE HIGH. FURTHER SOUTH...AN ELONGATED UPPER TROUGH 
REMAINS IN PLACE FROM 04N110W TO 10N140W...WITH A PARALLEL UPPER 
RIDGE FROM 06N110W TO 25N140W. DIVERGENT FLOW ALOFT BETWEEN 
THESE FEATURES IS ENHANCING CONVECTION ALONG THE ALONG ITCZ W OF 
115W. MEANWHILE A SURGE OF SW SWELL OF UP TO 8 FT WITH 16 SECOND 
PERIODS IS PUSHING NORTHWARD ACROSS THE EQUATOR MAINLY BETWEEN 
110W AND 130W. 

$$
CANGIALOSI