Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 241556
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC FRI MAY 24 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURE...

A 1009 MB LOW IS EMBEDDED WITHIN THE MONSOON TROUGH NEAR 10N106W 
MOVING WNW 10 KT. THIS AREA OF DISTURBED WEATHER CONTINUES TO 
PRODUCE DISORGANIZED SHOWERS AND THUNDERSTORMS. LATEST SATELLITE 
IMAGERY INDICATES THAT CONVECTION HAS DIMINISHED TO THE E AND SE 
OF THE LOW CENTER. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 120 NM SW SEMICIRCLE. THE LOW IS 
UNDERNEATH UPPER LEVEL RIDGING...AND OVER RATHER WARM SEA 
SURFACE TEMPERATURE. THESE INGREDIENTS MAY ALLOW THE LOW TO 
GRADUALLY INTENSIFY OVER THE NEXT 48 HOURS...WITH A MEDIUM 
PROBABILITY OF TROPICAL CYCLONE FORMATION.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH AXIS EXTENDS FROM 08N78W TO LOW PRES NEAR 10N88W 
1010 MB TO LOW PRES NEAR 10N106W 1009MB TO 08N120W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION FROM 05N TO 12N W OF 125W.

...DISCUSSION...

A GENERALLY RIDGE-TROUGH-RIDGE UPPER LEVEL PATTERN IS ANALYZED 
ACROSS THE DISCUSSION AREA. THE FIRST RIDGE EXTENDS N-NW FROM AN 
ANTICYCLONE LOCATED NEAR 12N127W AND IS COVERING THE WATERS W OF 
110W. THE TROUGH IS ALONG 30N120W 20N114W 11N116W. THE SECOND 
RIDGE IS BROAD IN NATURE...AND COVERS THE AREA E OF THE TROUGH. 
UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS HELPING TO INDUCE 
SOME CLUSTERS OF MODERATE TO STRONG CONVECTION VERY CLOSE TO THE 
PACIFIC COAST OF NICARAGUA...EL SALVADOR AND OVER THE EASTERN 
PART OF THE GULF OF TEHUANTEPEC...PARTICULARLY N OF 14N BETWEEN 
93W AND 95W. THE UPPER TROUGH WILL MOVE EWD TODAY REACHING THE 
NW PART OF MEXICO AS ANOTHER AND STRONGER UPPER LEVEL TROUGH 
REACHES THE FAR NW PORTION OF THE FORECAST AREA TONIGHT. 

AT THE SURFACE...A 1031 MB HIGH CENTERED NEAR 38N142W EXTENDS A 
RIDGE SEWD TO NEAR 20N118W. 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. UNDER THE 
INFLUENCE OF THIS RIDGE...MAINLY NE WINDS OF 15-20 KT ARE NOTED 
N OF THE ITCZ AND W OF 120W.  

THE REMNANTS OF ALVIN ARE STILL SEEN USING NIGHT CHANNEL VISIBLE 
IMAGES 11N136W. A TROUGH IS ANALYZED ACROSS THE AREA AND GOES 
FROM 12N35W TO BEYOND 9N140W. A MODEST REGION OF FRESH NE WINDS 
AROUND 20 KT CONTINUE N OF THIS TROUGH AND ARE PRODUCING SEAS 8-
9 FT. THIS TROUGH WILL CONTINUE W AND EXIT THE AREA LATER TODAY. 

STRENGTHENING HIGH PRES ACROSS THE GULF OF MEXICO WILL PRODUCE A 
BRIEF GAP WIND EVENT ACROSS THE GULF OF TEHUANTEPEC THIS 
UPCOMING WEEKEND. THE FORECAST CALL FOR WINDS REACHING 25 KT 
WITH SEAS TO 8 FT. WINDS ARE ALSO EXPECTED TO BRIEFLY INCREASE 
TO 25 KT ACROSS THE GULF OF PAPAGAYO PROBABLY IN ASSOCIATION 
WITH A DEVELOPING LOW PRES ALONG THE MONSOON TROUGH S OF 10N. 

LONG PERIOD CROSS EQUATORIAL SW SWELL AT 17-19 SECONDS DOMINATES 
MOST OF THE FORECAST WATERS E OF 115W. LONG PERIOD NW SWELL ARE 
INVADING THE NW WATERS. 

$$
GR/CHRISTENSEN