000 AXPZ20 KNHC 182336 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Oct 18 2022 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 2030 UTC. ...SPECIAL FEATURES... A strong cold front is moving across the Gulf of Mexico. Strong high pressure will build across the slopes of eastern Mexico creating a tight pressure gradient across the Tehuantepec region. Winds will start to funnel through the Chivela pass into the Gulf of Tehuantepec tonight, then increase to gale force Wednesday afternoon. The area of high pressure will shift eastward and weaken the second half of the week, loosening the pressure gradient. Winds will diminish below gale force Thursday, then further diminish, to 20 kt or less, this weekend. A trough of low pressure is located a few hundred miles south of the southern coast of Mexico. This system has become a little better organized since yesterday, and environmental conditions appear conducive for additional development. A tropical depression is likely to form in the next two to three days while the system moves generally west-northwestward, parallel to the southwestern coast of Mexico. This system has a medium chance of tropical cyclone formation through 48 hours and a high chance through 5 days. Regardless of development, increasing winds and building seas will be possible offshore southwestern Mexico by the end of the week into the weekend. Please refer to the latest NHC Tropical Weather Outlook at https://www.hurricanes.gov for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 79W north of 04N, moving west at around 10 kt. Nearby convection is discussed below. The axis of a tropical wave is near 98W north of 08N, moving west at around 15 kt. Nearby convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N86W to 14N98W to 09N123W to 11N140W. Scattered moderate isolated strong convection is noted north of 03N east of 80W, from 10N to 17N between 90W and 110W, from 07N to 11N between 110W and 130W, and from 08N to 13N between 130W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on an upcoming gale force gap wind event in the Gulf of Tehuantepec as well as possible tropical cyclone development offshore southwestern Mexico later this week. An earlier scatterometer pass showed fresh to strong winds south of southern Mexico off the coast of Oaxaca. Gentle to moderate NW-N winds are noted offshore Baja California north of Cabo San Lazaro as well as in the Gulf of California north of 27N. Light to gentle winds are noted elsewhere offshore Mexico. Seas are mainly 4-5 ft across the open waters, except 6-8 ft offshore Oaxaca and Chiapas. Seas are 3 ft or less in the Gulf of California, except to 4 ft north of 30N. For the forecast, other than the Gulf of Tehuantepec gale force gap wind event and possibly developing tropical cyclone off southwestern Mexico, gentle to moderate winds and moderate seas will prevail through next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate S-SW winds prevail across the offshore waters south of 10N, and light to gentle north of 10N. Seas are in the 4-6 ft range. For the forecast, moderate to occasionally fresh S-SW winds will prevail south of the monsoon trough. Light to gentle winds will prevail north of the monsoon trough, pulsing to moderate offshore southern Nicaragua and in the Gulf of Papagayo into the upcoming weekend. Moderate seas in S-SW swell will dominate the waters, building offshore Guatemala by mid-week due to a Gulf of Tehuantepec gap wind event. REMAINDER OF THE AREA... A cold front extends from 30N126W to 23N140W. A 1016 mb high is centered to the east near 30N122W. A set of NW swell with 7-8 ft seas is over the far NW waters. The pressure gradient between the area of high pressure and the monsoon trough is supporting moderate to locally fresh winds north of the monsoon trough to near 20N and west of 125W along with 6-7 ft seas. Gentle to locally moderate winds are elsewhere north of the monsoon trough, with seas in the 4-6 ft range. Moderate to fresh winds are south of the monsoon trough to the Equator and east of 110W, locally strong north of 08N. Gentle to moderate southerly winds are elsewhere south of the monsoon trough. Seas in the 6-8 ft range east of 120W, and 5-7 ft west of 120W. For the forecast, the cold front will drift east across the north-central waters, eventually dissipating over the next day or so. The set of long period NW swell will propagate across the NW waters, with another set of NW swell by the end of the week. A set of SW swell with seas of at least 8 ft will breach 03.4S and the Equator by mid-week. $$ AL