000 AXPZ20 KNHC 291510 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1510 UTC Wed May 29 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... ...Heavy Rainfall Potential Over Central America and Southern Mexico... A large low level cyclonic circulation that is typical for this time of the year, called a Central American Gyre, is forecast to persist across the far eastern tropical Pacific and Central America 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. Please refer to your local meteorological weather service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 1011 mb low pressure near 10.5N87W to 1008 mb low pressure near 14N99W to 07N125W. The ITCZ continues from 07N125W to beyond 07N140W. Scattered moderate convection is noted from 04N to 07N between 80W and 85W, and within 60 nm of the coast of Nicaragua and El Salvador. Scattered moderate to isolated strong convection is noted within 150 nm in the southeast quadrant of the low pressure near 14N99W. Scattered moderate convection also noted within 90 nm either side of the monsoon trough between 110W and 115W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong winds and building seas persist on the southern periphery of the 1008 mb low pressure centered near 14N99W. An earlier altimeter pass showed seas close to 11 ft already this morning south of the low pressure, and seas are expected to build to 9 to 11 ft beyond 120 nm off the coast of Chiapas later today, persisting through Fri as the low pressure moves inland over the isthmus of Tehuantepec. Farther north, 1007 mb low pressure was analyzed near 22.5N108W, about 90 nm southeast of Cabo San Lucas. This may be enhancing NW winds off Los Cabos, between the low pressure and a ridge farther west. An earlier scatterometer satellite pass showed fresh to moderate NW winds close to the Baja California coast. A concurrent altimeter pass indicated seas to 8 ft as well. The low pressure will weaken further through tonight, and winds and seas will diminish accordingly. 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 rains to parts of Central America and the adjacent offshore waters through the next several days. Latest surface observations indicate moderate to fresh S to SW winds S of the monsoon trough to 06N, with seas in the 8-10 ft range. S of 06N, light to gentle winds with seas in the 5-7 ft range prevail. Light to gentle winds, and seas of 7-8 ft prevail N of the monsoon trough. The southerly monsoon flow is forecast to strengthen to 20-25 kt off Guatemala today with seas building to near 12 ft by Thu as locally generated wind waves in the enhanced monsoon flow combines with cross equatorial SW swell. REMAINDER OF THE AREA... A ridge extends from 1027 mb high pressure near 35N138W to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ is supporting moderate to fresh NE winds across much of the area north of the ITCZ and west of 120W. Moderate to fresh winds will continue to prevail over this area the next several days. Long period cross equatorial SW swell will continue to dominate much of the forecast waters. Seas 8 ft or greater cover much of the waters south of 13N between 85W and 115W. Seas will slowly subside over the next couple of days, with areal coverage of seas 8 ft or greater gradually decreasing. $$ Christensen