757 AXPZ20 KNHC 252156 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Aug 25 2018 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...TROPICAL WAVES... A tropical wave axis is near 87W N of 03N, moving W at 15 kt. Associated convection is described in the Monsoon Trough section below and is occurring mostly E of the wave and extends across Central America and into the adjacent western Caribbean waters. A tropical wave axis is near 102W N of 02N, moving W at 15 kt. Associated convection is described in the Monsoon Trough section below and continues to impact the offshore shore coastal waters of Mexico between the Gulf of Tehuantepec and Cabo Corrientes. A tropical wave axis is near 122W from 05N to 20N, moving W around 15 kt. An associated 1011 mb surface low pressure center is located near 12.5N121.5W. Associated convection is described in the Monsoon Trough section below. A tropical wave axis is relocated from 10N133W to 06N137W, moving W at 10 to 15 kt. Associated convection is described in the Monsoon Trough section below and extends W of 140W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N74W TO 11N83W TO 09.5N92W TO 10N110W TO low pressure near 12.5N121.5W TO 15.5N132W TO 13N139W. Scattered moderate to strong convection is from 05N to 10N E of 86W, from 06.5N to 14.5N between 92W and 110W, from 06N to 11N between 110W and 116W, and from 09.5N to 19N between 118W and 142W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure of 1036 mb centered near 44N147W extends a broad ridge SE to near the Revillagigedo Islands. The associated pressure gradient between the high and a persistent trough across the Baja California Peninsula will support moderate NW winds funneling along the coast of Baja through the next several days, with seas generally 4 to 5 ft. The highest seas are expected off of Baja California Norte and may briefly increase to 6 ft. Low pressure will deepen over the SW United States, with a trough extending across the Gulf of California early next week. This will help to freshen winds offshore of Baja California Norte Mon night through Wed. Seas over this area will then gradually build to 6 to 8 ft. Meanwhile, gentle to moderate southerly flow will persist over the Gulf of California this weekend, occasionally pulsing to fresh across north portions. Winds are expected to diminish early next week across south portions of the Gulf leading to variable winds. In the Gulf of Tehuantepec this weekend, winds will be enhanced with the passage of a tropical wave currently along 102W, and area expected to pulse to fresh to strong tonight and Sun night, then only becoming fresh Mon Night. Late morning ASCAT data showed a narrow swath of easterly winds 20-25 kt behind the tropical wave and well offshore of the Gulf, from 11N to 13.5N between 94W and 100W. This area of fresh to strong winds will shift westward during the next 24 hours or so and may eventually build seas to 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will linger along 09N/10N during the next few days. Winds on both sides of the trough axis will generally be light to moderate. The main exception to this will be over the Gulf of Papagayo. Nocturnal offshore gap winds in the gulf this morning have diminished to around 15 kt this afternoon but will pulse to fresh to strong during the next several nights. REMAINDER OF THE AREA... The pressure gradient between ridging across the northern waters and the monsoon trough will support moderate to locally fresh trades and 4 to 7 ft seas in mixed swell north of the monsoon trough and west of 120W through the weekend. Active convection is expected to continue across this region for the next few days as ample low level moisture will accompany the tropical waves moving westward across the region. Wave heights will be relatively low for most of the forecast area this week. Long period swell is expected to arrive from the Southern Hemisphere this weekend. Associated seas near the Equator will build, and peak at 6-8 ft, late Sun through Mon. $$ Stripling