000 AXPZ20 KNHC 150912 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 912 UTC Sat Jul 15 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 is centered near 10.8N 121.8W at 0900 UTC, moving west at 10 kt. Estimated minimum central pressure is 948 mb. Maximum sustained winds are 125 kt with gusts to 150 kt. Numerous moderate to strong convection is within 60 nm of the center. Scattered moderate isolated strong convection is occurring elsewhere within 180 nm across the east semicircle and 240 nm across the southwest quadrant. Fernanda remains a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some additional strengthening is possible today. A gradual turn toward the west- northwest is expected later today, and this motion should continue through Sunday with strong easterly swell spreading out ahead of Fernanda. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 for more details. ...TROPICAL WAVES... A tropical wave extends north of 07N along 97W/98W, moving west at 15 kt. Scattered showers and a few thunderstorms are noted within 120 nm either side of the tropical wave axis. A tropical wave from 05N to 14N along 109W-110W is moving W at 15 kt. Scattered moderate convection is noted from 10N to 14N between 106W and 110W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N86W to 12N108W. The intertropical convergence zone reaches from 09N130W to beyond 07N140W. Scattered moderate convection is noted within 60 nm south of the monsoon trough axis between 85W and 90W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The subtropical ridge is building in the wake of the rapidly weakening remnant low of Eugene now well west of the region. This is allowing a tight enough pressure gradient to support moderate northerly winds off the coast of Baja California peninsula, pulsing to 20 kt over the next couple of nights. Seas across these waters will remain 4 to 6 ft 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. Mainly light and variable winds and 1-3 ft seas will prevail in the Gulf of California, except 3 to 4 ft seas south of 23N. Across the Gulf of Tehuantepec, moderate to fresh east to southeast winds are filling in across the region behind a passing tropical wave now just west of the Gulf. These winds will veer more southeasterly this morning along the Oaxaca coast. Weaker northerly gap winds will pulse each night afterwards. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, moderate offshore winds will pulse to fresh each night through Saturday morning, then weaken afterwards. Gentle to moderate southerly winds are expected south of the monsoon trough axis. Long period cross-equatorial southerly swell and 6-7 ft seas will continue to propagate into the waters west of Colombia and Ecuador, with a reinforcing pulse of swell moving into the area tonight reaching the Central America coast Saturday night and Sunday. REMAINDER OF THE AREA... Please see the special features section for information on Hurricane Fernanda. The post-tropical remnant low of Eugene near 29N129W is drifting northwest and dissipating, with no discernible convection. Fresh northeast winds on the north side of the low pressure will diminish later today. Swell generated by Fernanda will propagate away from the center across tropical waters west of 120W the next several days. It is expected to cross 140W and move into the Central Pacific by early next week. Elsewhere outside of the region within 300 nm of the path of Fernanda, winds will remain generally light to moderate with 5 to 7 ft seas. $$ Christensen