000 AXPZ20 KNHC 210946 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Apr 21 2017 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... A surface trough extends w from 08N84W to 06N101W. Scatterometer winds indicate that the ITCZ forms at 07N110W and extends w to beyond 05N140W. Isolated moderate to strong convection is observed along the trough within the area from 04N to 09N to the e of 97W, and also along the ITCZ within 45 nm either side of a line from 04N114W to 09N124W to 05N140W. A n to s orientated trough extends from 06N110W to 14N110W with scattered moderate isolated strong convection observed within 180 nm of 08N108W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends from nw to se across the offshore waters to the w of 111W. Fresh to locally strong northwesterly winds currently observed across the waters n of 25N, are expected to diminish to a moderate nw breeze this afternoon. The associated seas of 7 to 10 ft should subside to 5 to 7 ft by late Sat. Another round of large nw swell, in the form of 7 to 9 ft seas, will arrive at 29N120W on Sun, and spread s across the waters n of 25N by late Mon night before beginning to subside. However, a tightening pressure gradient will produce strong nw winds across the waters n of 29N e of 121w on Tue, and sending another batch of large seas s across the waters n of 25N. Gulf of California: Gentle to locally moderate nw flow forecast through this evening, then mostly a light to gentle nw breeze forecast on Sat, except for variable winds setting up around a surface low n of 30N on Sat night into Sun. Fresh to strong nocturnal sw winds expected near 30N114W on Sun, Mon and Tue nights. Gulf of Tehuantepec: Moderate northerly drainage flow expected at sunrise this morning. The next significant event is expected to begin on Sun evening, rapidly increasing to minimal gale force with seas to 12 ft late Sun night, then quickly diminishing on Mon morning. Only fresh northerly flow expected Mon night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds mostly onshore flow expected during the day becoming offshore at night. Combined seas of 3 to 5 ft in mixed SW and NW swell forecast during the next several days. REMAINDER OF THE AREA... A n to s orientated surface ridge along about 130W continues to block the eastern advance of cold fronts. Strong to near gale force southwesterly flow currently across the nw waters, will lift n of 32N this afternoon as the associated cold front enters the discussion area. The front will stall from roughly 32N128W to 25N140W on Sat. Large nw swell will build seas of 8 to 14 ft behind the front until it stalls. Expect the nw swell to propagate e reaching from the northern Baja Peninsula to 07N140W late this weekend, and then quickly subside early next week. Strong nw winds expected n of 28N e of 124W during the middle of next week. $$ Nelson