000 AXPZ20 KNHC 241600 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri May 24 2019 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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. ...SPECIAL FEATURES... A large cyclonic gyre that is typical for this time of the year, called a Central American Gyre, has developed. This feature called a Central American Gyre,is bringing abundant moisture across Central America. Expect heavy rainfall across sections of Central America during the next few days. Flash flooding and mudslides will be possible in areas of mountainous terrain. Please refer to your local meteorological service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from a 1008 mb low pressure center that is near 12N86W, to 10N106W, to 09N114W. The ITCZ continues from 09N114W to 07N124W to 07N132W, beyond 05N140W. Scattered to numerous strong rainshowers are along the coasts of Colombia and Panama from 06N to 08N from 79W eastward. Numerous strong rainshowers are within 90 nm on either side of the line that runs from 09N83W at the coast of southern Costa Rica to 06N85W to 04N86W. Numerous strong rainshowers are within 120 nm to the south of the monsoon trough between 85W and 91W Scattered moderate to isolated strong rainshowers are within 180 nm to the south of monsoon trough between 92W and 106W, and within 150 nm to the north of the ITCZ from 135W westward. Isolated moderate to locally strong rainshowers are within 180 nm to the north of the monsoon trough and the ITCZ between 99W and 127W, and within 210 nm to the south of the monsoon trough and the ITCZ between 106W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The latest scatterometer pass during the overnight hours was indicating moderate to fresh NW winds off the west coast of the Baja California peninsula, with sea heights in the range of 8 feet to 10 feet. Gentle to moderate winds prevail in the Gulf of California, with seas 3 ft or less. Gentle to moderate W to NW winds, with seas in the range of 5 feet to 7 feet, prevail over the remainder of the open waters off the coast of Mexico. Winds and seas off the coast of the Baja California peninsula will diminish today. Gulf of California: Gentle to moderate breezes will prevail across the Gulf of California through Saturday. By Sat night, SW gap winds will strengthen across the northern Gulf, ahead of a cold front approaching the region. Expect strong to near gale force gap winds north of 29.5N from Saturday night into Sunday, with strong winds persisting through Sunday night. The wind speeds will diminish by early next week. Gulf of Tehuantepec: Fresh to locally strong northerly winds will pulse across the Gulf of Tehuantepec region during the overnight and early morning hours this weekend with the assistance of the nocturnal drainage flow. The sea heights will build to 8 feet with the short-lived gap wind events. Fresh northerly winds early on Monday will diminish through early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please read the SPECIAL FEATURES section for more information about the Central American Gyre, which will bring heavy rains to parts of Central America and the offshore waters. Climatology with Central American Gyres: the monsoon trough lifts northward, and southerly monsoon flow will prevail over the forecast waters for much of the next several days. The monsoon circulation will dominate the regional pattern through early next week. It is likely that the winds to the south of the monsoon trough will strengthen from Monday through Tuesday. The wind speeds will be highly dependent on how the circulation around the Central America Gyre evolves during the next few days. The sea heights generally will remain at 8 feet or less through the weekend. The sea heights will build to 8-10 feet early next week, as SW swell mixes with locally generated wind waves due to the strengthening monsoon flow. REMAINDER OF THE AREA... Northwest swell continues to impact the waters north of 20N. Recent altimeter data indicate that the seas continue to peak near 11 ft N of 27N between 120W and 123W. This swell will subside during the next couple of days, with with seas falling to less than 8 feet late on Saturday. A surface ridge passes through 30N120W toward the Revillagigedo Islands. The pressure gradient between this ridge and lower pressure in the vicinity of the ITCZ is maintaining fresh to strong NE trades in the waters from 13N to 20N west of 137W, with seas in the 8-10 ft range. High pressure will weaken today, loosening the pressure gradient and diminishing the winds. The sea heights will begin to subside in response to the diminishing wind speeds. A set of SW swell will propagate into the southern forecast waters on Sunday, and continue to propagate northward through early next week. This will result in a large area of sea heights of 8 feet or greater south of 10N between 95W and 125W on Monday and Tuesday. $$ mt