000 AXPZ20 KNHC 010919 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 530 UTC Sat Jun 1 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... ...Heavy Rainfall Potential Over Central America and Southern Mexico... A large, low-level cyclonic circulation called a Central American Gyre will persist across southern Mexico, Central America, and the far eastern Pacific for the next several days. Locally heavy rainfall is likely to continue over portions of Central America and southern Mexico during the next several days. These rains could cause flash flooding and mudslides in areas of mountainous terrain. Abundant moisture will persist across the region this weekend. Please refer to your local meteorological service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends across Central America and southern Mexico, then passes through the coastal areas of Guerrero to 15N100W to 09N107W to 09N120W. The ITCZ continues from 09N120W to beyond 06N140W. Scattered moderate isolated strong convection is N of 06N between 80W and 83W, N of 15N to the coast of Mexico between 93W and 101W, and from 08N to 11N between 115W and 123W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate SW winds are noted south of the Tehuantepec region based on latest scatterometer pass. Seas have diminished below 8 ft based on altimeter data. A broad area of low pressure, currently centered near the west coast of the Yucatan Peninsula will maintain a moist monsoon flow across the offshore forecast waters of the States of Chiapas, Oaxaca and Guerrero this weekend keeping the likelihood of showers and tstms there. Elsewhere, a ridge north of 20N and west of Baja California is supporting gentle to moderate NW breezes off the Baja California coast. Little change in the overall pattern is expected through early next week. Gentle to moderate breezes will prevail in open waters, while fresh NW winds will pulse off Los Cabos in the late afternoon and evening hours. An ASCAT pass confirmed the presence of these wind speeds just off Los Cabos. Gulf of California: A trough will move through Baja California Norte and the Gulf of California today, supporting moderate to fresh SW gap winds over the northern part of the Gulf of California through Sun. Gentle to moderate winds are expected across the remainder of the Gulf of California over the next several days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section for more information about the Central American Gyre, which will continue to bring locally heavy rain to parts of Central America and the adjacent offshore waters through the next several days. Model guidance continues to suggest the Central American Gyre may finally break down early next week. This will diminish the risk of locally heavy rain over Central America. The most recent scatterometer data indicate gentle to moderate monsoon flow across the offshore forecast waters of Central America with seas of 5 to 7 ft. These marine conditions will persist during the weekend. A weak low pressure area may form along the coast near the border of Chiapas and Guatemala this weekend, with little impact in winds and seas. Farther south, seas will build to 7-8 ft in SW swell between Ecuador and the Galapagos Islands this weekend, and persist through Tue. Seas will briefly subside Tue night and Wed before another set of SW swell approaches the Galapagos Islands Wed night. REMAINDER OF THE AREA... A ridge extends from a 1030 mb high pressure centered near 34N142W southeastward to the Revillagigedo Islands. This system is producing mainly moderate to fresh NE to E winds across the waters W of 125W. An altimeter pass in this area showed 7-8 ft seas. The high pressure will remain nearly stationary this weekend while slightly weakening. As a result, the aerial extent and strength of the trades will decrease. Elsewhere, a set of SW swell is resulting in 8-9 ft seas roughly S of 02N between 98W and 120W. Expect 8-9 ft seas to persist south of the Equator this weekend. The leading edge of this swell event will propagate northward and reach the coasts of Mexico and Central America by late Sun, although wave heights are expected to remain less than 8 ft north of the Equator. Wave heights over the southern waters will gradually subside below 8 ft by Tue. Looking ahead, another set of SW swell will approach the far southern waters Wed night. $$ GR