000 AXPZ20 KNHC 301559 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Sep 30 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...TROPICAL WAVES... A tropical wave is along 100W north of 06N, moving west at 5 to 10 kt. Scattered moderate convection is noted from 10N to 15N between 94W and 103W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N86W to 10N130W. The ITCZ extends from 10N130W to 10N140W. Scattered moderate convection is noted from 05N to 14N and E of 120, and W of 125W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface ridging extends across the offshore waters of Mexico with a surface trough from SW Arizona to across the northern Gulf of California and Baja California Norte. Fresh to strong S-SW winds are in the northern Gulf of California due a tightening pressure gradient. Fresh N winds are noted in the Gulf of Tehuantepec. Winds are moderate or weaker elsewhere. Seas are 6-8 ft in decaying NW swell offshore Baja California, and 4-6 ft elsewhere in the open waters. In the Gulf of California, seas are 3-5 ft in the northern Gulf, and 1-3 ft elsewhere, except 3-4 ft near the entrance. A tropical wave is moving across portions of southern Mexico as described above. For the forecast, the NW swell offshore Baja California will continue to decay today. Otherwise, mainly moderate seas will prevail through the middle of next week. Fresh to strong N winds will pulse in the immediate area of the Gulf of Tehuantepec, mainly at night, through the weekend. Fresh to strong SW winds will pulse in the northern Gulf of California through Sun night due to a passing pre-frontal trough and weakening cold front. Winds will be moderate or weaker elsewhere. Looking ahead, an area of low pressure is expected to form well south of the coast of southwestern Mexico early next week. Environmental conditions are expected to support gradual development of the disturbance, and a tropical depression could form during the middle to later part of the week while the system moves generally northwestward. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Winds are moderate or weaker across the offshore waters. Seas are 3-5 ft N of 10N as well as offshore Colombia to the Azuero Peninsula, and 4-7 ft in SE-S swell elsewhere S of 10N, except 5-8 ft offshore Ecuador to the Galapagos Islands, highest S of the Galapagos Islands. Widely scattered showers and isolated thunderstorms are offshore western Panama northward. For the forecast, winds will be moderate or weaker across the offshore waters through the next several days. The southerly swell will gradually decay this weekend, then may build back offshore Ecuador to the Galapagos Islands by the middle of next week. Otherwise, expect moderate seas to prevail across the remainder of the waters. ...REMAINDER OF THE AREA... High pressure N of the monsoon trough/ITCZ is supporting fresh to strong winds from 13N to 17N and W of 130W. Moderate to fresh trades prevail elsewhere from 12N to 27N and W of 130W. Winds are moderate or weaker elsewhere as reported by recent ASCAT scatterometer data. A shrinking area of 8-11 ft seas dominates the waters from the Equator to 22N and W of 110W in mixed SE and NW swell. Seas are 8-11 ft in more pure SE-S swell S of the 10N and W of 95W. Seas are 4-7 ft across the remainder of the open waters, except 8-9 ft N of 25N between 119W and 126W in old N swell. For the forecast, the fresh to strong winds will diminish early today. Winds of moderate or weaker will prevail elsewhere and otherwise through the next several days. The elevated seas W of 110W will gradually decay through the weekend. A decaying cold front will push S of 30N by tonight with seas building to around 8 ft just S of 30N Sun afternoon into early next week, with a brief accompanying fresh northerly wind shift behind it. The southerly swell will decay slightly by the end of the weekend, however 7-9 ft seas will linger S of the Equator through early next week. $$ ERA