000 AXPZ20 KNHC 140903 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 903 UTC Fri Jul 14 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Hurricane Fernanda continues to strengthen this evening, centered near 11.0N 117.0W at 0300 UTC, or about 821 nm SSW of the southern tip of Baja California, moving W at 10 kt. Estimated minimum central pressure is 988 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Scattered to numerous moderate to strong convection is within 120 nm across the NE and 45 nm across the SW semicircles. Scattered moderate to strong convection is elsewhere within 150 nm NE and 90 nm SW semicircles. Fernanda is forecast to continue westward for the next few days, and gradually strengthen to a major hurricane by Sat. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 for more details. ...TROPICAL WAVES... A tropical wave extends along 94W/95W to across southeastern Mexico and the Gulf of Tehuantepec, moving W at 15 kt. The wave may be enhancing clusters o nocturnal convection within 60 nm of the Mexican coast between 95W and 102W. A tropical wave is along 104W moving W at 10 to 15 kt. Scattered moderate convection is noted from 12N to 14N between 100w and 104W. Satellite imagery suggests weak cyclonic turning in the middle levels of the atmosphere associated with this wave. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N78W to 11N110W, then resumes from 11N120W to 10N140W. Scattered moderate to isolated strong convection is noted north of 05N and east of 06N. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate northwest winds prevail offshore of Baja California this evening and are expected to remain gentle to moderate into the weekend. Winds will freshen modestly near the coast each afternoon through evening due to daytime heating through tonight. The remnant circulation of Eugene continues to dissipate and move away from the area, leaving light and variable winds farther offshore, generally W of 117W. Swells generated by Eugene will continue to affect the W coast of Baja California and southern California during the next day or so causing zones of dangerous surf and strong rip current conditions. Seas continue to subside gradually and are expected to maintain a range of 4 to 6 ft in south to southwest swell mixed with a component of northerly swell through early next week. Winds are expected to become light and variable again by early next week as broad troughing sets up across the offshore waters. In the Gulf of California, mainly light and variable winds will prevail, except occasionally pulsing to moderate out of the southeast in the northern Gulf each morning through noon. Seas will be 1 to 3 ft, except 3 to 4 ft near the entrance. In the Gulf of Tehuantepec, lower pressure south of the Gulf, enhanced in part by a passing tropical wave, is creating a tight enough gradient to support fresh to occasionally strong gap winds into the Gulf this morning and tonight. The winds tonight will veer more easterly along the Oaxaca coast, related to elongated lower pressure along the monsoon trough farther south. Weaker gap winds will pulse each night from Sat night through early next week. Elsewhere, mainly gentle variable winds and seas of 4 to 6 ft will prevail through the next several days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, moderate offshore nocturnal winds will pulse to fresh through Saturday morning, then will be weaker thereafter. Gentle to moderate southerly winds are expected south of the monsoon trough axis. Long period cross-equatorial southerly swell and seas 6 to 7 ft will continue to propagate through the waters west of Colombia and Ecuador, with a reinforcing pulse of swell moving across the area tonight and reaching the Central America coast by Saturday night. REMAINDER OF THE AREA... Please see the special features section for information on Hurricane Fernanda. Post-tropical cyclone Eugene was analyzed near 26N126W as a 1014 mb low center, drifting to the northwest and weakening with no discernible convection. An earlier scatterometer pass along with a concurrent altimeter satellite pass indicated winds of 20 to 25 kt and seas to 9 ft within 90 nm in the northern quadrant of the low pressure, but winds and seas have likely diminished since those passes yesterday. Winds and seas will continue to diminish over the next 48 hours as the low pressure gradually dissipates. Swell generated by Fernanda will propagate to within 300 nm of the center by early next week, with an accompanying wind field of 20 to 30 kt mainly on the northern periphery of the hurricane as it moves west of 140W by mid week. Elsewhere, outside of the region within 300 nm of the path of Fernanda, winds will remain generally light to moderate with 5 to 6 ft seas. $$ Christensen