000 AXPZ20 KNHC 012130 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Sep 1 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 2110 UTC. ...TROPICAL WAVES... A tropical wave is along 87W, moving W at 10-15 kt. Scattered moderate isolated strong convection is noted from 04N-11N between 83W-94W. This area of disturbed weather could become a tropical depression by the middle to latter part of next week as it moves west-northwestward, and it has a medium chance of tropical cyclone formation within the next 7 days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from Costa Rica near 09.5N84.5W TO 10N97W to 15N111W to 08N124W to 06N136W. The ITCZ continues from 06N136W to 06N140W. Scattered moderate convection is noted from 04N to 17N between 99W and 117W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Scattered moderate convection is noted to the south of Cabo San Lucas from 20N to 23N between 108W and 110W. A recent ASCAT satellite pass shows moderate to fresh SE winds in the central Gulf of California. Fresh to locally strong SE winds are likely occurring in the northern Gulf of California. Light to gentle winds prevail elsewhere. Seas are 6-7 ft W of Baja California, 3-5 ft in the northern Gulf of California, 2-4 ft elsewhere in the Gulf of California, and 5-6 ft elsewhere offshore of Mexico. Long period S to SW swell dominates, except north of Punta Eugenia, where NW swell is the dominant swell. For the forecast, pulsing fresh to locally strong S winds will continue in the northern Gulf of California through this evening before diminishing overnight. Fresh to strong northerly winds will pulse in the Gulf of Tehuantepec tonight through Sat night. Winds will be moderate or weaker elsewhere through Sat night. Winds will increase to fresh nearshore Baja California Sun evening through Mon night as the pressure gradient tightens along the peninsula. Looking ahead, an area of low pressure is expected to form several hundred miles offshore the southwestern coast of Mexico early next week. This low could begin strengthening by Wed, and it has a medium chance of becoming a tropical cyclone within the next 7 days. Areas well offshore Guerrero, well offshore Jalisco, and well south of the southern tip of Baja California could be impacted by increasing winds and seas during the middle to latter portion of next week. Please see the latest east Pacific Tropical Weather Outlook at hurricanes.gov for more details. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds prevail across the offshore waters N of 04N, except for stronger gusty winds in and near any strong thunderstorm activity. Seas north of 04N are 5 to 7 ft in south to southwest swell. To the south of 04N, including the waters offshore Colombia and in between Ecuador and the Galapagos Islands, moderate S winds with seas of 6 to 9 ft are present. Renewed long-period S to SW swell has reached a line from southern Equator to the Galapagos Islands, and will quickly spread N, reaching Panama and Costa Rica on Sat. Scattered moderate isolated strong convection is noted offshore Costa Rica in association with the tropical wave mentioned in the tropical waves section above. For the forecast, moderate to locally fresh south to southwest winds will continue between the coast of Ecuador and the Galapagos Islands through the weekend. Long period S to SW swell will move through these waters today into Sat, increasing seas to 8-9 ft through early Sun. Swell of 6-8 ft will reach the waters offshore Panama and Costa Rica this weekend. Elsewhere, light to gentle variable winds will prevail, except locally moderate to fresh near the Gulfs of Papagayo and Fonseca. ...REMAINDER OF THE AREA... The post-tropical remnant low of former Tropical Cyclone Irwin is centered near 18N140W with an estimated central pressure of 1010 mb. It is moving toward the west-southwest at 5 kt. A tight pressure gradient between the low and strong high pressure to its north is keeping fresh to strong winds in the northwest semicircle from the low to 22N and W of 137W. Seas are 10-12 ft in this area. Elsewhere from 18N to 26N and west of 135W, moderate to fresh NE winds and 7 to 10 ft seas prevail. A cold front has entered the area and extends from 30N126W to 29N130W to 29N140W. Moderate N winds and 7 ft seas are N of the front. Winds are mainly moderate or weaker across the remainder of the open waters north of 05N, with seas of 6 to 8 ft. South of 05N and east of 120W, moderate S winds and seas of 7-10 ft in long period S swell prevail. For the forecast, the post-tropical remnant low of Irwin will move west of 140W by this evening. Fresh to strong winds and elevated seas will continue to accompany the low. Elsewhere, renewed long period S swell is pushing northward across the Equator now with seas of 8-10 ft south of 06N and east of 120W, and this will prevail into Sat before subsiding late in the weekend. The broad north-south oriented surface trough near 20N is expected to move from along 117W to 120W by the weekend, resulting in shifting winds. Looking ahead, an area of low pressure is expected to form several hundred miles offshore the southwestern coast of Mexico early next week. This low could begin strengthening by Wed, and it has a medium chance of becoming a tropical cyclone within the next 7 days. Areas from 08N to 23N between 100W and 120W could be impacted by increasing winds and seas during the middle to latter portion of next week. Please see the latest east Pacific Tropical Weather Outlook at hurricanes.gov for more details. $$ Hagen