000
AXPZ20 KNHC 290907
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI APR 29 2011

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 
0830 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 06N78W 
TO 08N107W TO 02N140W. SCATTERED MODERATE TO STRONG CONVECTION 
IS NOTED WITHIN 120 NM N OF THE AXIS BETWEEN 117W AND 121W.

...DISCUSSION...
W OF 110W...A SMALL BUT VERY WELL DEFINED UPPER LEVEL CYCLONE 
CENTERED NEAR 25N139W IS MOVING RAPIDLY TO THE NE. ASIDE FROM 
AREAS OF MID AND HIGH LEVEL CLOUDINESS IN THE CENTER AND TO THE 
SE OF THIS FEATURE...IT IS HAVING LITTLE IMPACT ON THE SURFACE 
AS IT MOVES NE AND WEAKENS TODAY. THE MAIN INFLUENCE IS THE DEEP 
LAYER RIDGE ALONG 140W TO THE N OF THE UPPER 
CYCLONE...SUPPORTING A 1036 MB HIGH PRES CENTER NEAR 43N140W. 
THIS WILL STRENGTHEN SLIGHTLY THROUGH FRI AND INTO SAT AS THE 
UPPER LEVEL PATTERN BECOMES AMPLIFIED. SHIP OBSERVATIONS ON 
EITHER SIDE OF AN E-W ORIENTED COLD FRONT ALONG ROUGHLY 30N SHOW 
THE FRONT WEAKENING AS IT SAGS S. FRESH TO STRONG NORTHERLY 
WINDS PERSIST S OF THE HIGH PRES N OF 20N. SEAS OF 8 TO 9 FT IN 
NE SWELL WILL INCREASE TO 12 FT IN N SWELL OF THE NORTHERN BAJA 
COAST BY TONIGHT. FURTHER S...AN UPPER TROUGH EXTENDS FROM 
18N130W TO 06N120W. DIVERGENCE ALOFT ON THE SE SIDE OF THE 
TROUGH ALONG WITH MODERATE TRADE WIND CONVERGENCE IS MAINTAINING 
A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION N OF ITCZ 
BETWEEN 117W AND 121W.

E OF 110W...THE MAIN ISSUE WILL BE NEAR GALE FORCE GAP WIND FLOW 
THROUGH THE GULF OF TEHUANTEPEC FRI AS A COLD FRONT PUSHES INTO 
THE SW GULF OF MEXICO. THESE WINDS WILL BE RELATIVELY 
SHORT-LIVED...TYPICAL OF SPRING TIME EVENTS...AND WILL DIMINISH 
TO LESS THAN 20 KT BY LATE FRI. FURTHER S...FRESH GAP WINDS WILL 
ALSO BE ACTIVE THROUGH THE GULF OF PAPAGAYO DUE TO SLIGHTLY 
ENHANCED TRADE WINDS OVER THE WILL COMBINE WITH DRAINAGE EFFECTS 
TO RENDER GAP FLOW TO 20 KT TONIGHT AND EARLY SAT. 

GULF OF CALIFORNIA...W WINDS WILL INCREASE OVER THE NORTHERN 
PORTION OF THE GULF BETWEEN LOW PRES OVER NW MEXICO AND HIGH 
PRES OVER THE NE PACIFIC. 

$$
CHRISTENSEN