000 AXPZ20 KNHC 182156 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2130 UTC. ...SPECIAL FEATURES... Eastern Pacific Swell Event: Long-period NW swell began to subside across the Baja California and southwest mexico offshore waters. Seas range 8 to 9 ft and will continue to decay through tonight, with seas dropping below 8 ft by Tue night. A new set of long- period NW swell is entering the Baja California Norte waters behind a cold front that stretches from 30N120W to 29N131W. Seas to 12 ft can be expected north of Punta Eugenia tonight into early Tue morning. Seas will subside below 12 ft later on Tue into Tue night. This set of swell will decay completely by Wed night. 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 14N90W to 16N100W to low pres near 10N116W 1010 mb to low pres near 08N125W 1012 mb to 07N140W. Scattered moderate convection is noted from 12N to 17N between 88W and 105W and from 06N to 15N between 112W and 135W. ...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. Light to gentle winds are noted in the Baja California Norte waters north of Punta Eugenia ahead of an incoming cold front NW of the area. Moderate to locally fresh N to NW winds prevail across the rest of the Baja California offshore waters. A 1010 mb low pressure is noted off the southwest Mexico offshore waters near 18N105W. This low along with the ridging to its northwest is bringing fresh to locally strong winds to the southern Gulf of California offshore waters and southwest Mexico offshore waters. This is where seas range 6 to 9 ft, including the extreme southern Gulf. Meanwhile, the latest ASCAT data confirms gentle to moderate winds across the rest of the southern Mexico offshore waters and light to gentle winds in the Gulf of California. Seas to 3 ft are noted in the northern Gulf of California and moderate seas within NW swell are noted in the southern Mexico offshore waters. For the forecast, seas across the Baja California and southwest Mexico offshores will subside 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 morning. The NW winds along the Baja offshores will diminish to gentle to moderate speeds by Tue with seas subsiding below 8 ft by Wed night. Strong winds are expected over the southern Gulf of California through tonight and once again by Wed into Wed 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 to persist through early Sat. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate winds prevail across the Central and South American offshore waters. Seas range 4 to 6 ft across the area within mixed swell. The convection impacting some of the northern central American offshore waters has ended, with some isolated thunderstorms near Panama. For the forecast, gentle to moderate winds along with slight to moderate seas are expected 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. Winds may also become fresh to strong in the Gulf of Papagayo by Fri night into Sat night. ...REMAINDER OF THE AREA... Please refer to the Special Features sections for details about large swell propagating through the NE forecast waters. A cold front is entering the waters from 30N120W to 29N132W. This front is bringing fresh N winds behind it with 8 to 9 ft seas. Meanwhile, strong high pressure N of the area extends surface ridging to 12N. The pressure gradient between this and the monsoon trough is leading to widespread moderate to fresh winds N of the monsoon trough to 26N. Seas are 8 to 11 ft, with the highest 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 cold front will continue to press southward across the area, bringing fresh to strong winds behind it. The front will dissipate overnight into early Tue morning N of 25N. However, the large long-period NW swell will continue to propagate across the forecast region through Thu. Another set of swell will move into the forecast waters Thu night into Fri. 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