000 AXPZ20 KNHC 112153 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Sep 11 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 2145 UTC. ...SPECIAL FEATURES... A broad area of low pressure located a few hundred nautical miles southwest of the coast of southwestern Mexico is producing a large area of numerous moderate to strong convection from 16N to 20N between 101W and 111W, and from 13N to 15N between 111W and 118W. This activity is a little better organized this afternoon, and environmental conditions appear conducive for additional development. A recent ASCAT satellite data pass revealed an embedded low near 18N106W, with fresh to strong winds roughly within 180 nm of the low in the SE semicircle, and within 120 nm of the low in the NW semicircle. A ship with call sign "9HA5406" located just offshore Guerrero recently reported combined seas of 8 ft. A tropical depression is likely to form during the next couple of days as the system begins moving north- northwestward, near the coast of southwestern Mexico and toward the Baja California Peninsula. Regardless of development, heavy rainfall is likely across coastal portions of southwestern and west-central Mexico during the next couple of days. Currently, this system has a high chance of tropical cyclone formation in the next 48 hours and also through the next 7 days. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more information about this system. ...TROPICAL WAVES... A tropical wave, associated with the broad low pressure system as described above, has its axis along 106W from 10N to 20N. The majority of convection near this is related to the low pressure system described above under Special Features. Otherwise, scattered moderate convection is within 120 nm west of the wave from 12N to 14N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia to 12N86W to 16N100W to low pressure near 18N106W 1006 mb to 16N116W to low pressure near 13N124W 1008 mb to 11N130W. The ITCZ extends from 11N130W to beyond 10N140W. Numerous moderate to strong convection is seen within 180 nm south the trough between 77W and 86W. Scattered moderate to isolated strong convection is within 60 nm south of the ITCZ between 137W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to strong east to southeast winds are along and within about 60 nm offshore the coasts of southern Jalisco, Michoacan and northern Guerrero associated with the broad area of low pressure described above under Special Features. High pressure dominates the offshore forecast waters of Baja California supporting moderate to locally fresh northwest to north winds north of Cabo San Lazaro with seas of 5 to 7 ft, and gentle to moderate winds between Cabo San Lazaro and Cabo San Lucas with seas of 4 to 5 ft due to south swell. Light to gentle winds and slight seas are over the Gulf of California. For the forecast, fresh to strong southeast winds will develop over the central and southern Gulf of California out of this system beginning Thu. Elsewhere, a tightening pressure gradient between high pressure in the Pacific and deepening pressures in northern Mexico will support moderate to fresh northwest winds and moderate seas in northwest swell north of Punta Eugenia through early Fri, then mainly moderate winds and slight seas afterward. Farther south, a tropical depression is likely to form during the next couple of days as the system begins moving north- northwestward, near the coast of southwestern Mexico and towards the Baja California Peninsula. Regardless of development, heavy rainfall is likely across coastal portions of southwestern and west-central Mexico during the next couple of days. Please see the Special Features section for more details. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light and variable winds are over the Papagayo region along with seas of 4 to 6 ft in south to southwest swell. Elsewhere, gentle to moderate south to southwest winds are south f the monsoon trough while light to gentle winds are north of it. Seas are 4 to 6 ft in south to southwest swell, except 5 to 7 ft between Ecuador and the Galapagos Islands. For the forecast, gentle to moderate south to southwest winds will continue south of the monsoon trough through the rest of the week. North of the trough, light to gentle winds are expected. Moderate seas in primarily southwest swell will continue through the period, with the highest seas expected to peak to 6 or 7 ft between Ecuador and the Galapagos Islands through Thu. ...REMAINDER OF THE AREA... High pressure dominates the waters north of about west of 115W. Moderate to locally fresh anticyclonic flow is noted under the influence of this system with an area of fresh northeast winds from 15N to 22N west of about 125W as noted in partial ASCAT satellite data passes from this afternoon. Seas are 5 to 7 ft with these winds. Seas of 4 to 6 ft are noted elsewhere. Mainly moderate southwest to west winds continue south of the monsoon trough, with light to gentle winds north of it to near 20N and east of 125W. For the forecast, fresh southwest winds and building seas are expected south of the monsoon trough roughly between 108W and 123W through Thu as low pressure, possibly becoming a tropical cyclone, develops expect increasing winds and building seas across the offshore waters of southwestern Mexico on Thu, and across the waters between Cabo Corrientes and Los Cabos Thu night into Fri. Meanwhile, high pressure will continue to build north of 20N and west of 120W, with its associated gradient supporting moderate to fresh northeast winds and moderate seas through Fri. $$ Aguirre