Satellite imagery and NHC E Pac discussions are giving a heads up on a developing Tropical Wave in the Eastern Pacific.

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAY 30 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 100W FROM 03N TO 14N MOVING W 10-15 KT.
THE WAVE STRUCTURE HAS IMPROVED SLIGHTLY OVER THE PAST DAY AS
MID-LEVEL CYCLONIC TURNING HAS BECOME MORE PRONOUNCED ON
SHORTWAVE IR IMAGERY. CONVECTION HAS ALSO INCREASED AND IS LESS
LINEAR IN NATURE...MAINLY WITHIN 360 NM E OF THE ANALYZED AXIS.
THE WAVE REMAINS VERY BROAD WITH CLOUD MOTIONS SUGGESTING TWO
VORTICITY MAXIMUMS E AND W OF THE AXIS...NEAR 08N92W AND
08N103W. MANY OF THE GLOBAL MODELS SHOW SOME DEVELOPMENT OF THIS
SYSTEM OVER THE NEXT FEW DAYS AS IT MOVES W-NW....

AN UPPER RIDGE OVER THE TROPICAL EPAC...CENTERED S OF THE GULF
OF TEHUANTEPEC...IS PROVIDING A FAVORABLE ENVIRONMENT FOR
CONVECTIVE ACTIVITY NEAR THE TROPICAL WAVE DISCUSSED ABOVE. THIS
HIGH AND LOW-LEVEL CONVERGENCE ENHANCED BY NOCTURNAL DRAINAGE
FLOW OVER S MEXICO IS RESULTING IN MODERATE TO STRONG CONVECTION
OVER THE GULF OF TEHUANTEPEC AND OFF THE COASTS OF COSTA RICA
AND NICARAGUA.
http://www.nhc.noaa.gov/text/refresh/MIATWDEP+shtml/300918.shtml?