000 AXPZ20 KNHC 181424 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Nov 18 2024 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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 1430 UTC. ...SPECIAL FEATURES... Eastern Pacific Swell Event: Long-period NW swell has reached the outer offshore waters of Colima, Mexico. Seas continue to range 8-10 ft across the Baja California offshore waters. This set of swell will continue to decay, with seas dropping below 10 ft late tonight. Another set of long- period NW swell is forecast to enter the offshore and adjacent waters N of Punta Eugenia tonight. Seas will build to 14 ft just N of the area near 31N120W and to 12 ft S of 30N offshore Baja California Norte, subsiding to below 12 ft late Tue night into early on Wed. For more details, please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https//www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from the coast of Costa Rica near 12N86W to 15N101W to low pres near 09N121W 1009 mb to low pres near 08N127W 1009 mb to low pres near 07N131W 1009 mb to 07N140W. Scattered moderate to isolated strong convection noted from 10N to 16N between 89W and 97W. Scattered moderate convection is noted from 06N to 14N between 106W and 136W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on the swell event that is impacting the Baja California offshore waters. Strong high pressure and associated ridging prevail across the Baja California Peninsula offshore waters. Moderate NW winds prevail across the offshore Baja California. Fresh to locally strong NW to N winds likely still persist W of the southern tip of the peninsula and the Revillagigedo Islands. This is due to a tighter pressure gradient between the ridge and low pressure of 1007 mb that is located near 19N106W. Near this low, winds are fresh to strong. Moderate NW to N winds along with slight to moderate seas are over the northern and central Gulf of California while fresh to locally strong NW to N winds are over its southern section. Seas are moderate in this area. Generally, gentle to moderate W to NW winds along with seas of 7-10 ft in long-period NW swell are over the remainder of the Mexican offshore waters. Scattered thunderstorms are noted in the eastern offshore waters of Oaxaca, southeast of the Gulf of Tehuantepec. For the forecast, surface ridging will remain in place across the offshore waters of Baja California through mid-week. It will weaken slightly today allowing for the pressure gradient to slacken some. Seas across the Baja California and southwest Mexico offshores will subside into tonight. A new set of long- period NW swell following a cold front will reach the waters N of Punta Eugenia, bringing fresh to strong winds and seas peaking near 13 ft tonight into Tue evening. Afterward, NW winds along the Baja offshores will diminish to gentle to moderate speeds by Tue and continue through Fri night. Looking ahead, the next Gulf of Tehuantepec gap wind gale event is forecast to start Wed night. Gale force winds and very rough seas are forecast from Wed night through early Sat. An area of low pressure located just offshore of the coast of southwestern Mexico near 18N105W with a pressure of 1008 mb is producing convection to its E along the states of Colima and Jalisco, Mexico coast. Development of this system is not expected at this time. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate SW winds are ongoing across the Nicaragua, El Salvador and Guatemala offshore waters along with seas of 5-7 ft in mixed SW and NW swell. Gentle to locally moderate winds are across the remainder Central America offshore waters and from Ecuador to the Galapagos Islands. Seas are slight to moderate in mixed SW and NW swell across these waters. Otherwise, scattered showers and thunderstorms are evident over the offshore waters of Guatemala, El Salvador and northern Nicaragua. Some of these storms are producing frequent lightning and likely gusty winds. This activity is on the outer SW fringes of the remnant cyclonic circulation from former Tropical Storm Sara. For the forecast, moderate to fresh SW winds over the offshore waters from Nicaragua to Guatemala will change little through Tue, then diminish slightly on Tue night. Gentle to moderate winds along with slight to moderate seas are expected elsewhere through the end of the week. Looking ahead, a gale gap wind event is forecast to begin in Tehuantepec Wed night. Fresh to strong winds and very rough seas associated with this event are forecast to affect the far western Guatemala offshore waters Thu through Fri. ...REMAINDER OF THE AREA... Please refer to the Special Features sections for details about large swell propagating through the NE forecast waters. A tight pressure gradient related to a strong high pressure center located well NW of the discussion supports a large area of fresh to strong NE to E winds from the monsoon trough to 22N and W of 120W. Seas are 8-11 ft, the highest being W of 130W. Mostly moderate to fresh NE winds are N of 22N along with seas of 6-8 ft in long- period N to NE swell. Gentle to moderate winds along with seas of 6-9 ft due to long-period NW swell are south of the monsoon trough to 03N, and seas of 5-7 ft are S of 03N. For the forecast, the high pressure will be reinforced by another strong area of high pressure tonight. As a result, fresh to strong winds will continue to affect most of the waters N of 08N and W of 120W today and early this evening. Large long- period NW swell will continue to propagate across the forecast region. Seas of 8-12 ft will persist over the west-central waters through early this afternoon due to a combination of N to NE swell and wind generated waves. Seas in excess of 8 ft are forecast to cover most of the waters N of 05N and W of about 100W through late Tue night before subsiding. Looking ahead, rough seas generated by the Gulf of Tehuantepec gap wind event will move across the high seas waters W of 97W beginning Thu night and continuing through Sat. $$ AReinhart