000 AXPZ20 KNHC 232123 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Aug 23 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 2100 UTC. ...SPECIAL FEATURES... South of Southern Mexico: An elongated area of showers and thunderstorms located several hundred miles south of the coast of southern Mexico is associated with a trough of low pressure. Environmental conditions appear favorable for gradual development of this system, and a tropical depression is likely to form within the next two to three days while it moves slowly to the northwest or north-northwest. Currently, this system has a medium chance of tropical cyclone formation through 48 hours, and a high chance through 7 days. Please, refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is along 104 north of 05N, moving westward around 10 kt. Scattered moderate to isolated strong convection is noted ahead of the wave axis from 07N to 11N between 104W and 110W. A tropical wave is along 117W, from 04N to 16N moving westward at 10 to 15 kt. Scattered moderate to isolated strong convection is observed from 06N to 15N between 110W and 120W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N84W to 1007 mb low pressure located near 10.5N98W to 11N110W to 10N122W to 09N132W. The ITCZ extends from 09N132W to beyond 07N140W. Scattered moderate and isolated strong convection is from 06N to 15N between 80W and 127W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge dominates the offshore forecast waters of Baja California producing gentle to moderate NW winds N of Cabo San Lazaro, and light to gentle winds between Los Cabos and Cabo San Lazaro. Seas are generally 4 to 6 ft with mixed NW and SW swell. Light and variable winds are seen in the Gulf of California, with seas of 1 to 3 ft, except 3 to 4 ft near the entrance to the Gulf. Fresh to strong N gap winds are blowing across the Gulf of Tehuantepec and downwind to about 14N with seas to 8 ft. These winds are likely related to a developing low along the monsoon trough offshore Central America. A weak pressure gradient is supporting light to gentle winds elsewhere, with moderate combined seas primarily in SW swell. For the forecast, a ridge will continue the dominate the offshore waters of Baja California generating mainly gentle to moderate NW winds. Moderate to fresh winds are expected at night between Cabo San Lazaro and Punta Eugenia. Northerly gap winds will continue to pulse mainly at night across the Gulf of Tehuantepec into Fri. Looking ahead, an elongated area of showers and thunderstorms located several hundred miles south of the coast of southern Mexico is associated with a trough of low pressure. Please, see the Special Features section for more details. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recent scatterometer data indicate an area of fresh to locally strong SW winds across the offshore waters of northern Costa Rica and Nicaragua, where seas are in the 8 to 10 ft range based on altimeter data. Gentle to moderate SE winds are in the Gulf of Papagayo. These winds are related to a developing low along the monsoon trough. Scattered showers are ongoing in this area. Gentle winds and moderate combined seas are noted elsewhere in SW swell. For the forecast, the active monsoon trough will continue to support fresh to strong SW winds and rough seas off Costa Rica, Nicaragua and El Salvador through late Thu as the low pressure moves northward inland. Then, these winds and seas will diminish Fri as the monsoon trough lifts north of the area. Elsewhere, gentle to moderate winds and moderate seas, primarily in SW swell, will prevail. ...REMAINDER OF THE AREA... High pressure of 1029 mb is located well NW of the area near 41N146W. The associated ridge extends across the northern forecast waters, mainly N of 15N and W of 110W. The pressure gradient between the ridge and lower pressure in the vicinity of the monsoon trough supports and area of moderate to fresh winds from 12N to 17N between 120W and 130W. Fresh to locally strong winds are also noted in this area of winds near the convective activity just N of the monsoon trough. S of the monsoon trough, areas of fresh to strong S to SW winds are noted, particularly from 03N to 08N between 97W and 102W where a low pressure system is forecast to develop. Seas are 8 to 9 ft within these winds. Gentle to moderate winds are elsewhere under the influence of the ridge with seas of 5 to 7 ft primarily in northerly swell. For the forecast, fresh to strong SW winds will persist south of the monsoon trough and east of 120W through Thu. The surface ridge should strengthen on Fri into Sun, forcing fresh NE trades and seas 6 to 8 ft west of 120W from 10N to 20N. Looking ahead, an area of low pressure could form well south-southwest of the southern tip of the Baja California Peninsula within the next day or two. Environmental conditions are expected to be conducive for some gradual development of this system later this week and this weekend while it moves west-northwestward over the central portion of the tropical eastern Pacific. $$ GR