000
AXPZ20 KNHC 292132
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 29 2011

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...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 09N85W 
TO 03N96W TO 08N114W TO 06N130W TO 05N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS FROM 07N TO 11N BETWEEN 101W AND 
107W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 
90 NM N OF AXIS BETWEEN 123W AND 128W. 

...DISCUSSION...
W OF 110W...A SMALL BUT VERY WELL DEFINED UPPER LEVEL CYCLONE  
CENTERED NEAR 27N137W CONTINUED LIFTING QUICKLY N-NE LATE THIS 
AFTERNOON. A BROAD FLAT UPPER LEVEL RIDGE CONTINUES TO DOMINATE 
MUCH OF THE REMAINDER OF THE AREA TO THE E. ASIDE FROM AREAS OF 
MID AND HIGH LEVEL CLOUDINESS IN THE CENTER AND TO THE SE OF 
THIS LOW...IT IS HAVING LITTLE IMPACT AT THE SURFACE AS IT MOVES 
NE AND WEAKENS TONIGHT. A TROUGH EXTENDS FROM THE LOW TO ABOUT 
22N138W. A DEEP LAYER RIDGE N OF AREA AND ALONG 140W SUPPORTS A 
1038 MB HIGH PRES CENTER NEAR 41N134W. THIS SURFACE HIGH WILL 
STRENGTHEN SLIGHTLY AND SHIFT SLOWLY NE THROUGH SAT AS THE UPPER 
LEVEL PATTERN BECOMES AMPLIFIED. FRESH TO STRONG NORTHERLY WINDS 
PERSIST S OF THE HIGH PRES N OF 20N. A WINDSAT PASS FROM THIS 
MORNING VERIFIED THESE WIND SPEEDS. SEAS OF 8 TO 10 FT IN NE 
SWELL WILL INCREASE TO 13 FT IN NW SWELL OFF OF THE NORTHERN 
BAJA COAST BY TONIGHT. A DIFFLUENT PATTERN ALOFT BETWEEN THE 
AFOREMENTIONED RIDGE AND AN UPPER LEVEL CYCLONE SITUATED NEAR 
3N110W IS HELPING TO INDUCE MODERATE TO ISOLATED STRONG 
CONVECTION N OF THE ITCZ BETWEEN 101W AND 107W...AND NEAR THE 
NORTHERN END OF A SURFACE TROUGH THAT EXTENDS FROM 12N115W TO 
2N118W.  

AT LOW LEVELS E OF 110W...LIGHT AND VARIABLE WINDS CONTINUE AT 
THE SURFACE...WITH WEAK MONSOONAL FLOW E OF 90W. 

GULF OF CALIFORNIA...NW WINDS WILL INCREASE OVER THE NORTHERN 
PORTION OF THE GULF BETWEEN LOW PRES OVER NW MEXICO AND HIGH 
PRES OVER THE NE PACIFIC BY SAT MORNING AND THEN SPREAD S TO 25N 
THROUGH SUN...BUILDING SEAS IN EXCESS OF 6 FT. 

GAP WINDS...
NLY WINDS OF 20 TO 25 KT ARE BLOWING THROUGH THE GULF OF 
TEHUANTEPEC AS A COLD FRONT STALLS ACROSS 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 TONIGHT. 
IXTEPEC IN OAXACA MEXICO IS CURRENTLY REPORTING SUSTAINED WINDS 
OF 25 KT FROM THE N WHILE A RECENT ASCAT PASS SHOWS NLY WINDS OF 
20 KT DOWNSTREAM OF THE GULF TO 14N. 

FURTHER S...FRESH GAP WINDS HAVE ALSO BECOME ACTIVE THROUGH THE  
GULF OF PAPAGAYO DUE TO SLIGHTLY ENHANCED TRADE WINDS OVER THE 
CARIBBEAN AND WILL COMBINE WITH DRAINAGE EFFECTS TO RENDER GAP 
FLOW TO 20 KT THROUGH THE WEEKEND.

$$
GR