000 AXPZ20 KNHC 091608 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Jun 9 2021 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 1500 UTC. ...TROPICAL WAVES... A tropical wave is along 84W-85W extending from coastal Honduras and Nicaragua across Costa Rica and into the eastern Pacific. Associated moisture and scattered convection is occurring across the Caribbean with and behind the wave, and along the eastern Pacific monsoon trough. A tropical wave is along 104W-105W south of 15N. Scattered to numerous moderate to strong convection described below is along the monsoon trough, and ahead of the wave between 107W and 110W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N75W to 09N83W to 1011 mb low pressure near 11.5N93W to 11N100W to 1011 mb low pressure near 12.5N113W to 10N123W. The ITCZ reaches from 10N123W to 11N133W. Scattered moderate isolated strong convection noted from 02N to 09N between 78W and 88W. Numerous moderate scattered strong convection is noted from 07N to 14N between 88W and 105W. Scattered to numerous moderate isolated strong convection is noted from 07N to 15N between 105W and 116W. Numerous moderate to strong convection is noted from 05N to 08.5N between 135W and 141.5W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Generally moderate N-NW winds persist over the offshore waters of Baja California, except for small areas of 20 kt winds across the Baja Norte waters just north of 30N. Seas are 5 to 7 ft in lingering NW swell, with a few small areas to 8 ft per overnight altimeter data. Light to gentle breezes and slight seas persist across the Gulf of California. Forest and agricultural fires from Michoacan to Sinaloa may be supporting areas of moderate smoke and haze over adjacent offshore waters. Farther south, light to gentle breezes and 3 to 4 ft seas persist off southern Mexico. Building high pressure west of the area will support moderate to fresh NW winds off Baja California and building seas off the Baja California coast north of Cabo Lazaro starting tonight and then diminishing by Sat. Light to gentle breeze will persist off southern Mexico, with moderate SW swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... 1011 mb low pressure was analyzed along the monsoon trough well off the coast of El Salvador near 11.5N93W. This pattern is supporting moderate SE to E winds off El Salvador and Guatemala, which are converging with NE winds draining off the coast to support a line of showers and thunderstorms about 150 nm off the coast from roughly the Gulf of Papagayo to off western Guatemala. Light to gentle SW breezes are evident elsewhere off Central America. Seas are 4 to 6 ft in SW swell in most areas. A broad area of low pressure is expected to form a couple of hundred miles south of the coasts of southern Mexico, El Salvador, and Guatemala by Thursday. Environmental conditions appear favorable for some gradual development, and a tropical depression could form by the end of the week or over the weekend as the system drifts generally northward. Regardless of development, this system could produce heavy rainfall over portions of Central America and southern Mexico later this week and into the weekend. See products from your local meteorological service for more information. Elsewhere, farther south, a new round of large, long-period SW swell will reach Ecuadorian waters by Fri. REMAINDER OF THE AREA... Ridging dominates the waters north of 20N west of 115W, maintaining gentle to moderate breezes and 5 to 7 ft seas in NW swell. A broad upper trough extends roughly from 30N130W to 24N144W. Divergence aloft on the southeast side of this upper trough is supporting a weak surface trough from 06N to 12N between 132W and 134W, which shows up well in an overnight scatterometer satellite pass from around 06 UTC, which also showed fresh NW winds within 120 nm west of the trough. A concurrent altimeter satellite pass indicated seas starting to approach 8 ft in this area. A few showers are noted near this trough as well. A small 1011 mb low pressure area persists near 12.5N113W. Thunderstorms have been flaring for a few hours on the west side of this low. Elsewhere, moderate to fresh trades and 5 to 7 ft seas are noted from 05N to 20N west of 110W. Moderate to fresh SW winds and 4 to 6 ft seas are evident east of 110W. A ridge will build across the northern forecast waters during the next few days. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ will result in moderate to locally fresh trade winds roughly N of the ITCZ to about 20N and W of 125W through at least Fri, with seas of 5 to 8 ft. Looking ahead, lowering pressure off Central America will support increased SW winds and building seas over the waters mainly from 05N to 15N between 95W and 115W by late in the week. $$ Stripling