000 AXPZ20 KNHC 180249 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Jul 18 2017 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... Hurricane Fernanda is centered near 14.7N 132.2W at 0300 UTC or about 1355 nm WSW of the southern tip of Baja California or about 1345 nm E of Hilo, Hawaii moving NW at 8 kt. Estimated minimum central pressure is 967 mb. Maximum sustained winds remain 95 kt with gusts to 115 kt. Numerous moderate to strong convection is within 75 nm NE and 45 nm SW semicircle. Scattered moderate and isolated strong convection is elsewhere within 210 nm E na d120 nm W semicircles. The eye of Fernanda has become very ragged in satellite imagery this evening and has begun to fill, indicating a weakening trend. Gradual weakening is expected over the next several days. Large swells will continue to expand and spread out ahead of Fernanda to the NW and W during the next few days, and are expected to reach the Hawaiian Islands early Wednesday. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 for more details. Tropical Depression Seven-E near 14.3N 106.9W at 0300 UTC or about 310 nm SSW of Manzanillo, Mexico moving WNW at 8 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained winds are 30 kt with gusts to 40 kt. Scattered moderate to strong convection is within 120 nm in the SE semicircle, and also between 120 nm and 270 nm in the SW semicircle. The depression is forecast to strengthen to a tropical storm tonight with little strengthening thereafter through the next few days, then gradual weakening commencing by the end of the week. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 for more details. An area of low pressure centered near 14N117.5W 1008 mb, or about 675 nm SW of the southern tip of the Baja California peninsula. Scattered moderate to strong convection is within 180 nm in the S semicircle of the low. Fresh to strong winds and seas of 7 to 9 ft can be found within 180 nm in the SE semicircle of the low. The low will continue to move slowly to the W or WSW through midweek, and may eventually interact with Tropical Depression Seven-E. The low has a medium chance for tropical cyclone development during the next 48 hours. ...TROPICAL WAVES... The southern portion of a tropical wave reaches from the W Caribbean Sea to across Costa Rica and into the NE Pacific along 87W, moving W near 15 kt. Associated convection is described in the next section. A tropical wave reaches from the SW Gulf of Mexico across Mexico just W of the Gulf of Tehuantepec to along 98W, moving W near 10 to 15 kt. Associated convection is described in the next section. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N75W TO 10N92W TO 11N102W, where it breaks from Tropical Depression SEVEN-E. then resumes from 13N110W TO low pres near 14N117.5W TO 12.5N124W, where it breaks, then resumes to the SW of Fernanda near 11N132W TO 09.5N140W. Scattered moderate to strong convection is from 07N to 12N between 84W and 102W, and within 180 nm S of the trough between 132W and 139W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features for information on Tropical Depression Seven-E SW of Acapulco, Mexico. A surface trough from the coast of southern California southward to off the coast of the Baja California peninsula near 22N117W will continue to block the advance of the subtropical ridge into the region and maintain generally gentle to moderate winds off the Baja California peninsula through late week. Seas will still remain 5 to 7 ft however, in a mix of northerly and longer period S to SW swell. Farther S, moderate to fresh easterly winds will sweep across the Revillagigedo Islands on the N side of Tropical Depression Seven-E which is forecast to pass to the SW-W of the region by mid week. Gentle southerly flow will persist across the Gulf of California, except for moderate southerly flow over the northern Gulf. Light to gentle variable winds will prevail across the Gulf of Tehuantepec through midweek before fresh northerly gap winds pulse to strong at night. These winds will likely further increase to fresh to strong by the end of the week into next weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, moderate to fresh offshore winds will pulse to fresh each night with nocturnal drainage through the week, occasionally building seas close to 8 ft. Gentle to moderate southerly winds are expected S of the monsoon trough axis. Long period cross-equatorial southerly swell and 6 to 7 ft seas will continue to propagate into the waters reaching the coast of Central America through the day. Another pulse of large southerly swell will move into the waters by Tuesday and raise seas to 6-8 ft through Thu. REMAINDER OF THE AREA... Please see the special features section for information on Hurricane Fernanda. High pressure of 1031 mb well NW of the area near 38N162W extends a ridge E to SE through 32N140W to 22N130W. This is producing moderate to fresh N to NE winds across NW portions of the discussion area. The ridge will build modestly eastward through mid week and tighten the pressure gradient to the N of Fernanda as it moves W of 135W to produce fresh to strong NE winds across much of the NW part of the area, where seas will build to 8 to 9 ft through midweek. Swells generated by Fernanda will also propagate away from the center across tropical waters W of 120W the next several days. Northerly swell of 6 to 8 ft will propagate into the waters N of 25N and W of 120W, mixing with southerly swell generated from Fernanda tonight through Tuesday, creating combined seas of 7 to 9 ft. Elsewhere outside of the region within 360 nm to the N and NW of Fernanda, winds will remain generally light to moderate with 5 to 7 ft seas. $$ Stripling