000
AXPZ20 KNHC 212157
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAY 21 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...
AXIS ALONG 08N83W TO 12N99W TO 05N115W TO 04N140W WITH SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION WITHIN 120 NM OF AXIS E 
OF 103W.

...DISCUSSION...

A SURFACE 1031 MB HIGH JUST NW OF OUR AREA AT 34N146W IS THE 
MAIN FEATURE TODAY.  A MODERATE PRESSURE GRADIENT TO ITS 
SOUTHEAST IS FORCING SOME FRESH N WINDS JUST S OF 30N NEAR 120W 
AS WELL AS SOME FRESH NE TRADEWINDS BETWEEN 8N AND 18N W OF 
122W.  SEAS REMAIN LESS THAN 12 FT THROUGHOUT THE ENTIRE 
DOMAIN.  LITTLE SUBSTANTIAL CHANGE IS EXPECTED FOR THESE WINDS 
AND WAVES DURING THE NEXT TWO DAYS.

NO SIGNIFICANT TROPICAL FEATURES ARE ANALYZED CURRENTLY.  
THERE IS A REGION OF FRESH SW WINDS JUST SOUTH OF THE ITCZ 
BETWEEN 98W AND 110W AS SHOWN BY THE 1612Z ASCAT SATELLITE. A 
NEARLY SIMULTANEOUS TOPEX SATELLITE PASS REPORTED ABOUT 8 FT 
SIGNIFICANT WAVE HEIGHTS ALONG 110W.  THE GFS/WAVEWATCH MODELS 
INSTEAD THINK THAT 30 KT WINDS AND SEAS UP TO 14 FT ARE 
CURRENTLY OCCURRING...DUE TO A SPURIOUS LOW IN THE MODEL ALONG 
THE ITCZ.  THE HIGH SEAS FORECAST RELIES MORE UPON THE ECMWF 
MODEL...THOUGH BOTH THE GFS AND ECMWF SUGGEST THE SW WINDS 
SHOULD RELAX BELOW OUR 20 KT THRESHOLD WITHIN ABOUT 48 HOURS.

A SURGE OF FRESH S WINDS S OF 5N BETWEEN 85W AND 90W HAS BEEN 
OBSERVED TODAY VIA A 1152Z WINDSAT SATELLITE PASS.  THIS IS 
ACCOMPANIED BY SCATTERED MODERATE TO ISOLATED STRONG CONVECTION 
FROM 3N TO 8N BETWEEN 83W AND 94W.  IT IS ANTICIPATED THAT THESE 
WINDS AND CONVECTION WILL DIMINISH WITHIN A DAY.

NO GAP WIND EVENTS APPEAR LIKELY TO OCCUR WITHIN THE NEXT 
SEVERAL DAYS.

IN THE UPPER LEVELS...A DEEP LAYER TROUGH EXTENDS FROM 30N127W 
TO 16N143W TO 00N128W.  AN ASSOCIATED COLD FRONT THAT SAGGED 
SOUTH TOWARD 30N DISSIPATED THIS AFTERNOON AS THE SUPPORTING 
UPPER DYNAMICS SHIFTED E.  ELSEWHERE...A LARGE HIGH IS CENTERED 
NEAR 17N110W AND ANTICYCLONIC FLOW AROUND THE HIGH DOMINATES THE 
REMAINDER OF THE UPPER LEVELS.  

$$
LANDSEA