000 AXPZ20 KNHC 081002 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Sep 8 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURES... Tropical Depression Fifteen-E is centered near 18.5N 107.1W at 08/0900 UTC moving north-northwest at 3 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Satellite imagery indicates that convection has significantly increased during the past several hours. The convection consists of the scattered moderate to isolated strong type intensity within 150 nm of the center in the NE quadrant and within 120 nm of the center in the SE quadrant. Scattered moderate to isolated strong convection is also noted within 60 nm of a line from 19N104W to 17N104W. The depression is expected to make a turn to the northwest later today as it becomes a tropical storm. It is forecast to increase its forward speed through Fri. A turn toward the west-northwest is forecast by Fri night. On the forecast track, the center of the depression will move just to the southwest of southern Baja California Sur on Thu and Fri. It could become a short-lived hurricane Thu or Thu night. Weakening is expected on Friday when the system moves over colder waters. The depression is expected to produce total rainfall amounts of 1 to 3 inches with maximum amounts of 5 inches across the southern portions of Baja California Sur Thu through Fri. This rainfall may trigger flash flooding and mudslides. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Tropical Depression Fifteen-E Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave has its axis along 81W north of 03N to inland the central part of Guatemala. It is moving westward at 10 kt. Scattered moderate to isolated strong convection is increasing within 120 nm east of the wave from 11N-13N. A tropical wave has its axis along 100W from 02N to 18N. It is moving westward at about 10 kt. Isolated showers and thunderstorms are near the wave axis from 06N to 10N. A tropical wave has its axis along 139W from 02N to 15N, moving westward at 10-15 kt. No significant convection is noted. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from just inland northwestern Colombia to across southern Costa Rica to 10N86W to 11N92W and to 12N101W. It resumes at 14N115W to 12N125W to 15N136W and to 14N140W. Aside from the convection associated with Tropical Depression Fifteen-E and the tropical waves, scattered moderate to isolated strong convection is within 60 nm south of the trough between 93W-96W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on Tropical Depression Fifteen-E. A weak 1013 mb low is centered near 27N126W. A trough extends from it to 24N126W and northwest to 27N132W. No convection is occurring with this low as it is surrounded by a very dry and stable environment. Latest ASCAT data depicts gentle to moderate northwest winds off the Baja California peninsula with seas to 4 ft in long-period south to southwest swell. Earlier ASCAT data revealed light to gentle variable winds across the Gulf of California. Seas are less than 3 ft, except 3-4 ft just south of the entrance to the Gulf. Scattered moderate to isolated strong convection has moved offshore NW Mexico to over the northern Gulf of California during the overnight hours. Scattered moderate convection is just inland Mexico from northern Jalisco to southern Nayarit due to the northeast fringe of Tropical Depression Fifteen-E. Overnight ASCAT data showed fresh to strong east- southeast winds on the outer periphery of Tropical Depression Fifteen-E along and offshore the coast from Jalisco to Guerrero. Earlier altimeter data showed seas of 8-9 ft in that area. Otherwise, light to gentle variable winds are across the Nayarit offshores in addition to Oaxaca and Chiapas. Seas are 5-7 ft in long- period southwest swell. Tropical Depression Fifteen-E is forecast to turn to the northwest later today as it becomes a tropical storm. It is forecast to increase its forward speed through Fri. A turn toward the west- northwest is forecast by Fri night. On the forecast track, the center of the depression will move just to the southwest of southern Baja California Sur on Thu and Fri. The strengthening cyclone is expected to generate swells that will affect portions of the coasts of Baja California Sur and Sinaloa by Thu, spreading northward along the west coast of Baja California Sur through Fri. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. In the Gulf of California, light and variable winds will continue through Thu night,then become moderate southeast winds. Light to gentle winds will continue across southern Mexico. Fresh to strong gaps winds could develop across the Gulf of Tehuantepec beginning Thu night and continuing into the upcoming weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate southwest winds are south of the monsoon trough with light and variable winds are north of the monsoon trough. Seas are 3-6 ft in the Central American offshore waters and 6-7 ft seas off of Ecuador and the Galapagos Islands. Satellite imagery shows scattered showers and thunderstorms along and just offshore the coast of Costa Rica. Scattered showers and thunderstorms are along and just inland the coast of Colombia from 02N to 05N. Seas are 3-6 ft in the Central American offshore waters, except for higher seas of 5-7 ft over the waters between Ecuador and the Galapagos Islands due to a southwest swell. These seas will build to 6-8 ft due to a southwest swell beginning Wed. Winds in Papagayo region will become moderate southerly in direction beginning Fri and increase to fresh speeds Sat. Moderate to fresh southwest winds are expected along the offshore waters of Costa Rica, Panama, Colombia, Ecuador and Galapagos Islands Tue through the end of the week. Strong south to southwest winds are expected over the offshore waters of Guatemala and El Salvador late Sat through late Sun as low pressure develops south of the southern coast of Mexico. Seas in these waters will remain in the 6-7 ft range, except near 8 ft seas in the region west of Ecuador. Seas offshore Guatemala, Honduras and El Salvador are expected to build to possibly 9 ft during Sat and Sat night due to the expected strong south to southwest winds combining with southwest swell that will be propagating through those same offshore waters. REMAINDER OF THE AREA... Broad high pressure dominates the waters north of the monsoon trough, with the gradient between it and lower pressure to the south in the monsoon trough region allowing for moderate to fresh north-northeast winds and seas 7 ft south of 15N and west of 115W. Gentle to moderate southerly winds remain south of the monsoon trough, with seas to 7 ft. Seas to 8 ft due to a southwest swell continue south of the Equator and west of the Galapagos Islands through this morning before another set of southwest swell begins to propagate through the waters west of the Galapagos Islands from Thu through the upcoming weekend. $$ Aguirre