000 AXPZ20 KNHC 200930 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0930 UTC Sat Jan 20 2018 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 0815 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N74W to 04N85W to 05N98W. The ITCZ continues from 05N98W to 09N126W then resumes W of a surface trough near 08N138W to beyond 07N140W. Scattered moderate with isolated strong convection is noted from 10N to 15N between 114W and 130W. Scattered moderate convection is within 90 nm N of the ITCZ axis between 110W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Strong to near gale winds will continue through this morning, then will diminish briefly below 20 kt this afternoon. The winds will pulse to strong tonight, then drop below 20 kt late Sunday morning through Monday. A plume of NE swell associated with the strong winds in the area the past few days continues to propagate well away from Tehuantepec, and mix with open ocean long period NW swell. This swell will diminish below 8 ft over these waters by late today. Looking ahead, strong to near gale winds are expected again beginning Monday night and prevailing through Wednesday. Gulf of California: SW winds are increasing to fresh to strong this morning just south of a cold front approaching the northern Gulf. These winds will spread south ahead of the front today. Fresh to strong NW winds are expected to develop behind the cold front in the northern gulf later this morning. The front will gradually become ill defined later today as it moves southward with winds diminishing to moderate to fresh this evening. The pressure gradient will then begin to tighten across the area Sunday as low pressure over interior SW United States intensifies, leading to fresh to strong winds across mainly the central and southern portions of the Gulf Sunday evening through Monday. These winds will then slowly diminish Monday night through Wednesday. Elsewhere across the offshore waters of Mexico, large NW swell continues to propagate SE across the area, with seas of 8-13 ft prevailing. This large swell is producing high surf along coasts and outer reefs of Baja California and mainland Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong NE gap winds will decrease through the late morning. These gap winds are expected to return during the overnight hours midweek. Elsewhere N of 09N, light to gentle offshore flow will prevail. Gentle southerly winds will prevail S of 09N for the next few days. REMAINDER OF THE AREA... Large long period NW swell continues to propagate SE across the forecast waters. Seas 12 ft or greater prevail over much of the forecast waters north of 25N, currently peaking near 16 ft as confirmed by a recent altimeter pass. Seas 8 ft or greater cover nearly all the the open waters N of 06N. Fresh to strong trades will prevail north of the ITCZ to around 20N for the next several days, supporting combined seas of 10 to 13 ft from the ITCZ to 25N W of 115W through early next week. A surface trough embedded in the vicinity of the ITCZ along 130W is helping to generate convection across the area mainly east of the trough axis. This convection is discussed in the ITCZ section. $$ Latto