Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 250923
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC SAT MAY 25 2013

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 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH AXIS EXTENDS FROM 10N86W TO LOW PRES NEAR 09N88W 
1009 MB TO LOW PRES NEAR 10N97W 1010 MB TO LOW PRES NEAR 11N107W 
1009 MB TO 08N122W. ITCZ AXIS EXTENDS FROM 08N122W TO 08N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 120 NM S 
OF AXIS BETWEEN 90W AND 94W...FROM 08N TO 10N BETWEEN 108W AND 
114W...AND FROM 08N TO 10N BETWEEN 119W AND 123W.

...DISCUSSION...

ALOFT...AN UPPER LEVEL TROUGH CROSSES NEAR 30N140W. STRONG SW 
FLOW AHEAD OF THE TROUGH IS TRANSPORTING ABUNDANT MID TO UPPER 
LEVEL MOISTURE ACROSS THE NW PART OF THE FORECAST AREA. A CUT-
OFF LOW IS FORECAST TO DEVELOP ALONG THE TROUGH AXIS AND WILL 
MOVE ACROSS THE NW PART THROUGH EARLY SUN. ANOTHER UPPER TROUGH 
EXTENDS FROM NW MEXICO ALONG SOUTHERN BAJA CALIFORNIA TO NEAR 
13N110W. BETWEEN THESE UPPER LEVEL TROUGHS...BROAD ANTICYCLONIC 
FLOW IS NOTED. ANOTHER ANTICYCLONE DOMINATES THE WATERS E OF 
105W...INCLUDING SE MEXICO AND NORTHERN CENTRAL AMERICA. THIS 
SYSTEM CONTINUES TO PROVIDE A FAVORABLE UPPER LEVEL ENVIRONMENT 
FOR CONVECTION ALONG AND NEAR THE MONSOON TROUGH. 

THERE ARE THREE LOW PRES SYSTEMS EMBEDDED IN THE MONSOON TROUGH. 
THEY ARE LOCATED NEAR 09N88W...10N97W AND 11N107W. THESE LOWS 
ARE PRODUCING DISORGANIZED CLOUDINESS AND SHOWERS AND NONE OF 
THEM ARE SHOWING SIGNS OF ORGANIZATION AT THIS MOMENT. 
SCATTEROMETER DATA SHOW MAINLY GENTLE TO MODERATE WINDS IN 
ASSOCIATION WITH THESE LOWS. ENVIRONMENTAL CONDITIONS APPEAR 
FAVORABLE FOR SOME GRADUAL DEVELOPMENT OF THE LOW PRES LOCATED 
NEAR 09N88W AS IT DRIFTS WESTWARD. DEVELOPMENT OF THE LOW PRES 
LOCATED NEAR 11N107W SHOULD BE SLOW TO OCCUR AS IT MOVES LITTLE 
DURING THE NEXT COUPLE OF DAYS. SOME TROPICAL DEVELOPMENT IS 
SEEN IN MOST OF THE GLOBAL MODELS. THE GFS IS THE MOST 
AGGRESSIVE INDICATING GENESIS AND INTENSIFICATION OF TWO LOW 
PRES. IT WILL BE INTERESTING TO CONTINUE WATCHING THESE AREAS 
OVER THE NEXT FEW DAYS. SEE LATEST TROPICAL WEATHER OUTLOOKS FOR 
PROBABILITY CONDITIONS RELATING TO THESE LOW PRES FEATURES.

AT THE SURFACE...A 1030 MB HIGH IS ANALYZED NW OF THE AREA AT 
35N144W WITH A RIDGE EXTENDING SEWD TO NEAR 21N116W. THE TIGHT 
PRES GRADIENT BETWEEN THE RIDGE AND LOW PRES OVER THE WRN U.S. 
CONTINUES TO RESULT IN STRONG NW-N WINDS JUST N OF THE FORECAST 
WATERS WITH SEAS THERE UP TO AROUND 11 FT. AN ALTIMETER PASS 
PROVIDED OBSERVATIONS OF SEA HEIGHTS OF AROUND 9 FT ACROSS THE N 
WATERS WHILE A COUPLE OF SHIPS REPORTED SEAS OF 9-10 FT ALONG 
30N. THE MOST RECENT SCATTEROMETER DATA REVEALED NE TRADES OF 15-
20 KT OVER THE WEST-CENTRAL WATERS FROM N OF THE ITCZ TO NEAR 
20N AND W OF 120W WITH SEAS TO 9 FT IN MIXED NE AND NW SWELL. 
THESE MARINE CONDITIONS WILL PERSIT OVER THE NEXT COUPLE OF 
DAYS...WITH SEAS SUBSIDING TO 8 FT IN THE REGION OF THE TRADE 
WINDS.

STRENGTHENING HIGH PRES ACROSS THE GULF OF MEXICO WILL PRODUCE A 
BRIEF GAP WIND EVENT LASTING ONLY ABOUT 6-9 HOURS ACROSS THE 
GULF OF TEHUANTEPEC EARLY ON SUN WITH N WINDS OF 20-25 KT AND 
SEAS TO 8 FT. NE-E WINDS ARE ALSO EXPECTED TO BRIEFLY INCREASE 
TO THE RANGE OF 20-25 KT ACROSS THE GULF OF PAPAGAYO...MOST 
PROBABLY ATTRIBUTED TO THE AFOREMENTIONED DEVELOPING LOW PRES 
OVER THE FAR ERN PART OF THE FORECAST AREA ALONG THE MONSOON 
TROUGH. 

LONG PERIOD CROSS EQUATORIAL SW SWELLS AT 16-18 SECONDS DOMINATE 
MOST OF THE FORECAST WATERS E OF 115W...WHILE LONG PERIOD NW  
SWELLS ARE SPREADING ACROSS THE NRN PORTION. THESE SWELL EVENTS 
ARE FORECAST TO MERGE LATER TODAY. 

$$
GR