000
AXPZ20 KNHC 220957
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC FRI MAY 22 2015

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM  
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY  
THROUGH 0945 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
          
SCATTEROMETER WINDS INDICATE THAT THE ITCZ FORMS NEAR 08N86W AND 
CONTINUES SW TO 05N97W...THEN TURNS NW TO 10N115W. ISOLATED 
MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 120 NM EITHER 
SIDE OF A LINE FROM 06N93W TO 03N103W TO 04N115W. THE ITCZ IS 
INTERRUPTED W OF 115W BY THE BROAD CYCLONIC FLOW ASSOCIATED WITH 
TWO SURFACE LOWS. THE EASTERNMOST LOW IS CENTERED NEAR 08N122W 
ALONG A NE TO SW ORIENTATED TROUGH THAT EXTENDS FROM 13N117W TO 
02N125W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
N OF 09N WITHIN 150 NM EITHER SIDE OF A LINE FROM 14N113W TO 
10N125W...AND WITHIN 180 NM OF 04N126W.

A SECOND SURFACE LOW IS ESTIMATED NEAR 08N137W AT 1009 MB AND 
CURRENTLY LACKS SIGNIFICANT CONVECTION. ISOLATED MODERATE TO 
STRONG CONVECTION IS NOTED BETWEEN THE TWO LOW PRESSURE CENTERS 
FROM 02-12N BETWEEN 130-140W. 

...DISCUSSION...

AN UPPER CYCLONE IS MOVING ACROSS THE CALIFORNIA COAST AT 34N  
WITH AN UPPER SHORTWAVE TROUGH EXTENDING SE ACROSS THE GULF OF 
CALIFORNIA. AN ASSOCIATED SURFACE TROUGH EXTENDS S ACROSS THE 
NORTHERN GULF OF CALIFORNIA WITH S-SW 20-25 KT WINDS OBSERVED 
ACROSS THE GULF WATERS N OF 30N E OF THE TROUGH. EXPECT THE 
GRADIENT TO RELAX EARLY TODAY WITH WINDS DIMINISHED TO 15-20 KT 
BY THIS AFTERNOON. 

AN UPPER ANTICYCLONE IS CENTERED OVER THE TROPICS NEAR 11N113W 
WITH AN UPPER RIDGE EXTENDING W TO BEYOND 11N140W. ADDITIONALLY 
A KELVIN WAVE HAS MOVED E INTO THE WESTERN PORTION OF THE 
DISCUSSION AREA...AND COMBINES WITH THE UPPER DIFFLUENCE ALONG 
THE UPPER RIDGE TO ENHANCE THE CONVECTION NEAR THE TROPICAL 
SURFACE LOWS. GLOBAL MODELS SUGGEST SLOW DEVELOPMENT OF THE 
EASTERNMOST LOW PRES THAT IS EXPECTED TO REACH NEAR 10N127W 
TONIGHT WITH THE GRADIENT SUPPORTING NE 20-25 KT WINDS 
DEVELOPING WITHIN 360 NM NW-N OF THE LOW WITH SEAS BUILDING 7-11 
FT. THE LOW SHOULD REACH NEAR 11N131W ON SAT NIGHT. TROPICAL 
CYCLONE DEVELOPMENT IS POSSIBLE AFTER 48 HOURS. 
   
LONG PERIOD SOUTHERLY SWELL AT 14-18 SECONDS IS OBSERVED ACROSS 
THE TROPICS S OF 03N BETWEEN 85-120W WITH COMBINED SEAS OF 7-9 
FT. THESE SOUTHERLY SWELLS WILL SPREAD N REACHING THE PACIFIC 
COAST OF MEXICO AND CENTRAL AMERICA TONIGHT WITH SEAS SUBSIDED 
TO 4-6 FT.

GULF OF PAPAGAYO...GUIDANCE INDICATES NE-E 20-25 KT WINDS WILL 
DEVELOP OVER AND JUST SW OF THE GULF OF PAPAGAYO LATE TONIGHT 
THROUGH THE EARLY MORNING ON SAT...AND AGAIN ON SAT NIGHT INTO 
EARLY SUN. SEAS ARE EXPECTED TO BUILD TO 8 FT WITH THE RESULTANT 
NE SWELL PROPAGATING W AND MIXING WITH LONG PERIOD CROSS-
EQUATORIAL SWELL ACROSS THE PACIFIC WATERS FROM 09-11N BETWEEN 
88W AND 93W ON SAT. 

$$ 
NELSON