000 AXPZ20 KNHC 282008 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Oct 28 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 1900 UTC. ...TROPICAL WAVES... A tropical wave is near 87.5W from 03N northward to across the Gulf of Fonseca and portions of central America, moving west at 15 to 20 kt. Scattered moderate isolated strong convection is noted from 05N to 09N between 84W and 90W. A tropical wave is near 98.5W from 03N northward to southwestern Mexico, moving west at 15 to 20 kt. Scattered moderate convection is noted from 08N to 14N between 99W and 106W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends off the coast of Costa Rica near 09N83.5W to 08N100W to low pressure, Invest EP91, near 10.5N126.5W to 08.5N to 129W. The ITCZ extends from 09N129W to beyond 08.5N140W. Scattered moderate convection is noted from 02N to 09N between 77W and 84W, from 08N to 14N between 109W and 125W, from 09N to 12.5N between 127W and 132W, and from 06N to 12N between 135W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong to near gale-force winds are in the Gulf of Tehuantepec where seas are 8 to 14 ft. Otherwise, a high pressure ridge dominates the offshore forecast waters of Mexico producing mainly gentle to moderate NW winds across the remainder of the offshore waters, except now moderate to fresh offshore Baja California Norte. Seas are 4 to 6 ft in mixed swell outside of the Tehuantepec region, except building to 8 ft offshore Baja California Norte in new NW swell. In the Gulf of California, light to gentle winds and seas of 1 to 3 ft are noted, except to 4 ft near the entrance. For the forecast, strong to near gale-force northerly winds will persist in the Gulf of Tehuantepec through tonight, then fresh to strong through Tue afternoon with similar winds pulsing Thu night and Fri night. Otherwise, high pressure will surge southward behind a weak cold front tonight into Tue, leading to increasing northwest winds offshore Baja California. Fresh to locally strong winds can be expected there through Tue night. As the front passes, winds in the northern Gulf of California will also pulse to strong tonight and early Tue. NW swell will also spread offshore Baja California during this time, with seas reaching 12 ft north of Cabo San Lazaro tonight through Tue night. Winds should diminish to moderate across these areas Wed, while seas slowly subside through Thu. Looking ahead, a new area of large NW swell may impact the waters offshore Baja California starting Fri through at least Sat night. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong NE winds are present across the Papagayo region per recent ASCAT scatterometer data, where seas are up to 7 to 8 ft. Elsewhere, gentle to locally moderate winds prevail. Seas are mainly 4 to 6 ft in southerly swell, mixed with NW swell offshore Guatemala and El Salvador where they are up to 8 to 10 ft due to an ongoing Gulf of Tehuantepec gap wind event. Scattered thunderstorms are present offshore Colombia, Panama and Costa Rica as described in the monsoon trough and tropical waves sections above. For the forecast, fresh to strong offshore winds will pulse across the Papagayo region through early Tue, and again Tue night, with moderate to fresh winds otherwise through Wed night. Gentle to moderate winds will prevail elsewhere, freshening south of the monsoon starting Wed night, then possibly becoming strong toward the end of the week. Mainly moderate seas in cross equatorial southerly swell will continue to propagate across the offshore forecast waters, potentially building to near 8 ft south of the monsoon trough toward the end of the week into the weekend. Meanwhile, seas generated in the Tehuantepec region will continue to spread across the outer offshore waters of Guatemala and El Salvador through tonight, with seas up to 10 ft. ...REMAINDER OF THE AREA... A trough of low pressure, the remnants of Kristy is near 132.5W from 17N to 24N. Fresh to strong winds are present across the majority of the waters north of 19N and west of 129W due to a tight pressure gradient between the trough and building high pressure into the northern waters in the wake of a cold front north of 30N. Seas of 8 to 13 ft in mixed NW to N swell and remnant swells generated by ex-Kristy are present west of a line from Baja California Norte near 31N116W to 20N131W to 11N135W, highest in the NW waters per recent altimeter data. Meanwhile, a broad area of low pressure of 1008 mb, Invest EP91, located more than 1000 nautical miles southwest of the southern tip of the Baja California peninsula near 10.5N126.5W is producing disorganized shower activity, with fresh winds and seas to 8 ft nearby. Also, a weak area of low pressure about 900 nautical miles south-southwest of the southern tip of the Baja California Peninsula is producing disorganized showers and thunderstorms, with fresh winds and seas to 7 ft nearby. Gentle to moderate winds and 5 to 7 ft seas prevail across the remainder of the open waters, except 7 to 9 ft downwind of the Gulf of Tehuantepec due to a prolonged gap wind event. For the forecast, the remnants of Kristy trough will shift west- southwestward through mid-week. This feature combined with high pressure building southward from north of 30N will support fresh to strong winds across the waters north of 20N and west of 130W, shifting west-southwestward through early Wed along with the trough. Large NW swell will continue to spread southeast while mixing with swells generated by former major hurricane Kristy resulting in very hazardous seas across the waters north of 10N and west of 125W through mid-week. Meanwhile, although the chances of development appear to be decreasing with Invest EP91, a tropical depression could still form in a few days while the system moves westward at about 15 kt. This system is expected to cross into the Central Pacific Basin by the end of the week. Also, some slow development is possible during the next 3 to 4 days with the low to the east of Invest EP91 while it moves slowly to the west-northwest. By the end of the week, however, strong upper-level winds should end the chances of development. The area of hazardous seas in mixed swell will cover waters north of a line from Cabo San Lazaro, Mexico to 12N140W by early Tue, with seas greater than 12 ft in some locations. The seas will then gradually decay into Thu. Looking ahead, another large set of northerly swell may push south of 30N starting Thu night, with seas of 8 ft greater covering much of the waters north of 10N and west of 115W by Sat evening. $$ Lewitsky