000
AXPZ20 KNHC 221531
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN MAY 22 2011

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
 
...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED ALONG 
12N85W TO 13N95W TO 05N125W TO 01N135W TO 02N140W. NUMEROUS 
MODERATE TO ISOLATED STRONG WITHIN 30 NM EITHER SIDE OF AXIS 
BETWEEN 86W AND 93W...WITHIN 90 NM OF THE COAST OF CENTRAL 
AMERICA BETWEEN NW NICARAGUA AND SOUTHERN MEXICO. SCATTERED 
MODERATE CONVECTION WITHIN 60 NM N OF AXIS BETWEEN 125W AND 
130W.  

...DISCUSSION...

AN UPPER TROUGH EXTENDING FROM SOUTHERN CALIFORNIA TO NEAR 
25N135W IS BECOMING LESS AMPLIFIED AS RIDGING BUILDS FROM THE 
WEST...LEAVING AN UPPER CYCLONE CUT OFF NEAR 16N142W. 1031 MB 
SURFACE HIGH ASSOCIATED WITH THE BUILDING MID TO UPPER LEVEL 
RIDGE IS CENTERED NEAR 35N135W. SCATTEROMETER DATA SHOW A BROAD 
AREA OF FRESH TO STRONG TRADES S OF THE HIGH PRES...FROM 07N TO 
20N W OF 125W. ALTIMETER DATA CONFIRM WAVEWATCH AND ECWAVE 
INITIALIZATIONS SHOWING SEAS TO 9 FT MAINLY W OF 130W WITHIN 
THIS AREA OF TRADES. THE TRADES WILL DIMINISH SLIGHTLY OVER THE 
NEXT COUPLE OF DAYS AS THE HIGH PRES TO THE N WEAKENS AHEAD OF A 
COLD FRONT ADVANCING INTO THE NE PACIFIC.

SHARP UPPER LEVEL TROUGHING EXTENDS FROM THE CUT OFF UPPER 
CYCLONE TO 00N116W. SCATTERED MODERATE CONVECTION IS NOTED WHERE 
DIVERGENT FLOW ALOFT ALONG THE TROUGH AXIS INTERSECTS THE 
ITCZ...BETWEEN 125W AND 130W. 

MODERATE TO FRESH NORTHERLY FLOW PERSISTS N OF 26N E OF 125W TO 
THE NORTHERN COAST OF BAJA CALIFORNIA. THESE WINDS WILL PUSH 
DOWN THE COAST OF BAJA THROUGH LATE TUE AS THE SURFACE HIGH 
MOVES EASTWARD. NW TO N SWELL UP TO 10 FT WILL ACCOMPANY THE 
WINDS...MAINLY N OF 25N E OF 125W. 

A 05Z ASCAT PASS SHOWED 20 KT S TO SW WINDS PERSISTING S OF THE 
ITCZ IN THE AREA BETWEEN 100W AND 110W. THIS IS INTERACTING WITH 
N TO NE LOW LEVEL FLOW N OF THE ITCZ RESULTING IN A WELL DEFINED 
CIRCULATION ALONG THE ITCZ NEAR 113W. THE CIRCULATION WILL 
REMAIN EMBEDDED WITHIN THE ITCZ FOR THE NEXT COUPLE OF 
DAYS...BUT WITH UPPER SUPPORT NOT FAVORABLE TO SUPPORT 
APPRECIABLE CONVECTION AND WITH THE SOUTHERLY FLOW 
DIMINISHING...NO FURTHER DEEPENING IS EXPECTED.

FURTHER EAST...AN UPPER TROUGH EXTENDS FROM YUCATAN TO NW COSTA 
RICA...E OF AN UPPER ANTICYCLONE CENTERED OVER 15N105W. 
DIVERGENT FLOW ALOFT BETWEEN THESE UPPER FEATURES IS AIDING 
DEVELOPMENT OF A LARGE AREA OF MODERATE TO STRONG CONVECTION 
NOTED WITHIN 180 NM S OF THE ITCZ AXIS E OF 95W...OFF THE COAST 
FROM NICARAGUA TO SOUTHERN MEXICO. THIS ACTIVITY IS ALSO 
ENHANCED BY LOW LEVEL CONVERGENCE OF MODERATE SW FLOW S OF THE 
ITCZ...AND WEAK OVERNIGHT DRAINAGE FLOW OFF THE CENTRAL AMERICAN 
COAST.  

$$
CHRISTENSEN