000 AXPZ20 KNHC 292037 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1953 UTC Sun Oct 29 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Significant swell event that will produce heavy surf conditions has reached the offshore forecast waters of Baja California. The leading edge of a swell train, with periods of 19 to 22 seconds, is reaching the Revillagigedo Islands with seas of 8 to 11 ft. This will bring large breaking waves of 20 ft and higher along the coast of Baja California Peninsula through Monday. Some of the swell energy could refract into the southern Gulf of California late tonight and Monday. Expect for the swell energy to bring rough surf conditions to those coasts. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from a 1010 mb low pressure near 11N91W to another 1010 mb low pressure near 12N102W to 12N115W to 10N130W to 07N135W, where it transitions to the ITCZ and continues beyond 07N140W. Scattered moderate convection is within 75 nm NW quadrant of low near 11N91W. Similar convection can be found N of 14N between 97W and 103W, within 90 nm NE quadrant of low near 12N102W, and from 08N to 10N between 115W and 117W. Isolated moderate convection is from 07N to 12N between 120W and 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Significant swell event: please refer to the special features section above for information on swell affecting the Pacific coast of Mexico through Monday night. Gulf of Tehuantepec: A late evening scatterometer pass indicated winds to near 30 kt over the Gulf of Tehuantepec, with winds likely peak to minimal gale early this morning. Since that time, the loss of nocturnal enhancements through the Chivela Pass have lessened and therefore the gale for winds have most likely ended. However, strong to near gale-force N to NE winds will continue over the Gulf of Tehuantepec through today with seas of 8 to 12 ft. Winds will gradually diminish overnight with peak winds of 25 kt through Monday morning, before diminishing below 20 kt by Monday afternoon. Nocturnal enhancements to near 20 kt will occur each night during midweek. Gulf of California: Light and variable winds today will increase to moderate to locally fresh and generally from the south over the gulf N of 25N Monday through Tuesday as a trough of low pressure develops over the Baja Peninsula. A weak surface ridge currently extending southeastward from a 1018 mb high center located at 28N134W to near the Revillagigedo Islands will maintain a gentle to moderate NW breeze along the Pacific coast of Baja California and Mexico offshores waters N of the Tehuantepec region through Tuesday night. The ridge will become elongated west to east by midweek, extending to near Baja California. This will allow for light to gentle winds over the area and seas of 4 to 6 ft over these waters for the middle of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Post Tropical Cyclone Selma has dissipated inland over NW Honduras, allowing winds and seas to subside in the vicinity of El Salvador. Even though Selma has dissipated, heavy rainfall will only gradually taper off along the pacific coast of Central America during the next couple of days. Otherwise, mainly gentle to moderate winds and seas of 4 to 6 ft will prevail for these waters through Mon night. Winds N of 10N could become light and variable on Tue as the monsoon trough becomes reestablished in this area. REMAINDER OF THE AREA... A 1018 mb high center analyzed at 28N134W has a ridge axis that extends southeastward to near the Revillagigedo Islands. This ridge is maintaining light to moderate NE winds over the waters N of 15N and W of 120W. The high center will gradually shift northward and weaken through Monday night. This pattern will continue to support mainly gentle to moderate winds over these waters through midweek. Moderate to occasionally fresh SW winds are expected to the south of the monsoon trough through Tue night. Long-period NW swell is already producing seas in the range of 8 to 12 ft over the NW waters. The swell will continue spreading to cover most of the waters W of 115W by tonight. Conditions will gradually improve over the northern waters Monday into Tuesday as the large swell decay and propagate into the southern waters. The swell over the southern waters will continue to decay and allow seas in this area to diminish below 8 ft by midweek. $$ GR