AXPZ20 KNHC 062151

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Wed Dec 6 2023

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.


Gulf of Tehuantepec Gale Warning: Strong high pressure stretches over central Mexico, supporting northerly gale force winds across the Gulf of Tehuantepec. Strong winds likely stretch as far south as 12N. Seas currently range between 7 and 10 ft. This pattern will persist through Thu. Seas expected to reach as high as 12 ft tonight into Thu morning. Gale-force winds will end by Thu evening, with the strong winds diminishing by Fri. Seas will also subside below 8 ft on Fri.

Please read the latest High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.


The monsoon trough extends from the coast of Colombia near 07N78W to 06N99W to 07N111W. The ITCZ extends from 07N111W to 10N121W and then from 07N128W to beyond 07N140W. Scattered moderate to isolated strong convection is noted from 04N to 09N between 133W and 140W. Scattered moderate convection is noted from 03N to 08N between 77W and 82W and from 03N to 11N between 87W and 130W.


Please read the Special Features section for more information on the Gale Warning in the Gulf of Tehuantepec.

A broad ridge extends across the offshore waters of Baja California from weakening high pressure. The pattern is supporting gentle to locally moderate northerly winds across most of the Baja California offshore waters. Moderate N to NW winds prevail over the southern Gulf of California, including the entrance of the Gulf with light to gentle winds in the northern Gulf. NW swell across the Baja California waters is bringing 8 to 11 ft seas mainly over the waters beyond 60 nm of the Baja California coastline. Seas range 2 to 4 ft across the Gulf of California. Farther south, light to gentle breezes persist off southern Mexico with 4 to 6 ft combined seas in mixed swell.

For the forecast, outside of the gap winds in the Gulf of Tehuantepec, long-period NW swell will persist off Baja California and the Revillagigedo Islands through Sat. Seas as high as 12 ft could move across the Baja California Norte waters later today and into tonight. Reinforcing NW swell will arrive off Baja California Norte by Thu night into Fri, accompanying a decaying cold front moving into the region. Swells will subside later in the weekend. Strong winds could develop across most of the Gulf of California this weekend, producing rough seas. Another strong gale-force wind event could occur over the Gulf of Tehuantepec late this weekend into early next week with very rough seas.


Fresh to strong NE to E winds prevail across the Gulf of Papagayo, where seas are near 5 to 7 ft. Gentle to moderate winds elsewhere over the region. Seas range 5 to 7 ft in the Guatemala and El Salvador offshore waters mostly within N to NW swell due to the influence of the Gulf of Tehuantepec gap wind event. Elsewhere, seas range 3 to 5 ft seas primarily in S to SW swell. Scattered showers and thunderstorms are noted south of the monsoon trough off the coast of Colombia.

For the forecast, high pressure north of the region will support pulsing strong winds across the Gulf of Papagayo at night through the weekend. Seas could reach 8 ft downwind of the event. Seas will build well offshore of Guatemala tonight into Thu due to swell generated by gale- force gap winds in the Gulf of Tehuantepec. Gentle to moderate winds are forecast elsewhere. Moderate combined seas will persist through the weekend in a mix of SW and NW swell.


High pressure dominates the waters north of 20N. Fresh to locally strong trade winds persist south of the ridge, mainly 07N to 23N west of 110W. Seas in this region are 8 to 13 ft, in a mix of seas due to the trade wind flow, and long-period NW swell. A cold front stretches in the NW corner of the basin from 30N130W to 26N140W with scatterometer data depicting moderate to fresh N to NE winds behind the front. A large reinforcing NW swell is bringing 10 to 14 ft seas N of 12N and W of 120W. Combined seas of 8 to 10 ft cover much of the region elsewhere W of 115W, although with primarily S to SE swell S of 04N. Gentle to moderate winds and 4 to 7 ft seas are noted east of 110W. A surface trough is analyzed along 124W from 08N to 12N with scattered moderate convection near them.

For the forecast, the cold front will continue to move across the waters tonight before decaying by Thu while weakening the high pressure. This will allow for trade winds to diminish slightly W of 115W today into tonight. Large, long- period NW swell accompanying the front will continue to move across the waters N of 10N and W of 120W through tonight supporting seas to 14 ft N of 20N and W of 130W. E of 115W, the combination of the NW swell with shorter- period NE swell emerging from gap wind events and fresh E trade winds will support rough seas from 07N to 12N between 95W and 110W from Thu into Fri. This swell event will begin to subside by the weekend and into early next week.

$$ AReinhart