000 AXPZ20 KNHC 281451 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 UTC surface analysis and satellite imagery through 1410 UTC. ...TROPICAL WAVES... A tropical wave is near 85.5W from 03N northward to across portions of central America, moving west at 10 to 15 kt. Scattered moderate convection is noted from 04N to 09.5N between 84W and 90W. A tropical wave is near 96W from 03N northward to Oaxaca, Mexico, moving west at around 10 kt. Scattered moderate convection is noted from 08N to 13N between 93W and 100W. ...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 11N125W to 09N129W. The ITCZ extends from 09N129W to 08N134W to beyond 09N140W. Scattered moderate convection is noted from 03N to 09N between 77W and 82W, from 07.5N to 14N between 100W and 122W, and from 06N to 12N between 127W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong to near gale-force winds are in the Gulf of Tehuantepec while gale force winds have likely diminished after sunrise. Seas are 8 to 16 ft in the Tehuantepec region. 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. 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, 1 to 3 ft seas 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. ...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 where seas are up to 7 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 9 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, then decrease to moderate to fresh through early Wed. 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. Meanwhile, seas generated in the Tehuantepec region will continue to spread across the outer offshore waters of Guatemala and El Salvador into tonight, with seas up to 9 ft. ...REMAINDER OF THE AREA... Low pressure, Invest EP91, is embedded in the monsoon trough near 11N125W at 1008 mb. Winds near the center are 20 to 25 kt, with a broader area of fresh NE to E winds along and north of the monsoon trough axis between 120W and 130W. Disorganized showers and thunderstorms are along the monsoon trough near this low. Broad and weak low pressure has formed about 1000 nautical miles southwest of the southwestern coast of Mexico in the monsoon trough. Meanwhile, 1008 mb low pressure, the remnants of Kristy, are analyzed near 21N132W with some scattered showers possible near it. Fresh to strong winds are within 180-240 nm in the NW quadrant of this low. Moderate to fresh NE winds are found across much of the waters elsewhere north of 10N and west of 130W, with gentle to moderate winds found across the remainder of the open waters. NW swell with seas of 8 ft or greater is found NW of a line from near San Diego, California to 10N140W, up to 13 ft just southeast of 30N140W. Seas are 5 to 7 ft 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 will become a trough through today while shifting west-southwestward. 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. Meanwhile, environmental conditions appear generally conducive for gradual development of Invest EP91, and a tropical depression could form within the next few days while it moves westward at about 15 kt. This system is expected to move into the central Pacific basin by the end of the week. Also, some slow development is possible with the broad and weak low pressure well SW of the southwestern coast of Mexico during the next 3 to 4 days while the low 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. $$ Lewitsky