182 AXPZ20 KNHC 131545 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1545 UTC Mon Aug 13 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...TROPICAL WAVES... A broad tropical wave is along 114W-115W with a 1011 mb surface low along the wave at 10.5N115W. This system is progressing W at 10-15 kt. Scattered moderate to strong convection is observed from 08N to 15N between 113W and 118W, with a prominent band around 210 nm from the center of the low in the western semicircle. Environmental conditions are forecast to become a little more conducive for development by the middle part of the week, and a tropical depression could form late this week. A tropical wave is analyzed along 126W/127W from 06N to 20N. Scattered moderate convection is noted from 14N to 18N between 123W and 128W. Scatterometer data and other satellite imagery show a weak surface low may be starting form along this wave. Some development of this system is possible during the next day or two before upper- level winds and water temperatures become less conducive. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 11N113W. The intertropical convergence zone extends from 14N120W to 10N140W. Numerous moderate to scattered strong convection is noted within 210 nm of the coast of Central America and southern Mexico south of 18N, with the strongest convection south of the monsoon trough off Panama and Costa Rica. This is mainly related to overnight drainage flow convergence. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Ship observations along Pacific coast of Baja California indicate moderate to fresh NW winds funneling along the coast between Punta Eugenia and Cabo San Lazaro. These are the result of a locally tight pressure gradient between weak ridging just off the coast, and the weak 1014 mb remnant low of former tropical cyclone John west of the offshore area near 28N123W. Gentle to moderate breezes are noted elsewhere over open waters with 3 to 5 ft seas. The surface low will drift eastward toward Guadalupe Island, but weaken to a trough later today then dissipate through mid week, allowing winds off Baja California to diminish. Farther south, long period SW swell will move into the offshore waters between Puerto Angel and Cabo Corrientes, with combined seas reaching 6 to 8 ft Tue into Thu, with highest seas south of the Gulf of Tehuantepec. Looking ahead, fresh to strong gap winds are expected by Thu night in the Gulf of Tehuantepec. Light to gentle southerly breezes are noted across the Gulf of California, occasionally pulsing to moderate to fresh over the northern Gulf mainly at night. A few showers and thunderstorms are active over the central Gulf of California resulting from a mid/upper level trough pivoting across northwest Mexico and local overnight drainage convergence. Little change is expected. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to locally strong E drainage flow expected tonight followed by fresh nocturnal easterly flow through Fri morning. Gentle to occasionally moderate E winds are forecast elsewhere N of the monsoon trough which is meandering between 09N and 11N. Moderate to locally fresh southerly winds are forecast S of the monsoon trough through early next week. Long period S to SW swell will spread into the regional waters late Mon and raise offshore seas to 7 to 8 ft on either side of the Galapagos Islands, before a strong and larger pulse of SW moves into the regional waters Tue. This next pulse of cross equatorial swell will raise seas to 7-9 ft Wed through early Thu before slowly subsiding through Fri. REMAINDER OF THE AREA... The remnant low of former tropical cyclone Kristy is centered near 23N135W and estimated at 1013 mb. Winds have diminished to 20 to 25 kt, with 6 to 7 ft seas, within 90 nm over the NW quadrant. This low pres center has been moving slowly westward that past 24 hours, but is forecast to gradually accelerate to 10-15 kt over the next few days and slowly dissipate as it approaches 140W Tue evening. The remnant low of former tropical cyclone John is centered near 28N123W and estimated at 1014 mb is drifting NE and weakening to a trough today. Fresh NE winds of 15-20 are occurring within 210 nm over the NW semicircle tonight and will weaken as the low opens to an open trough. Long-period cross-equatorial southerly swell, in the form of 7 to 10 ft seas, will propagate N across the tropical waters S of 20N E of 120W Tue night through Thu, and then subside to less than 8 ft on Thu night. $$ Christensen