000 AXPZ20 KNHC 152200 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 1945 UTC. ...SPECIAL FEATURES... Hurricane Fernanda is centered near 11.4N 124.0W at 2100 UTC or about 1060 nm SW of the southern tip of Baja California, moving W at 11 kt. Estimated minimum central pressure is 955 mb. Maximum sustained winds are 115 kt with gusts to 140 kt. Numerous strong convection is within 60 nm east and 45 nm west of the center. Scattered moderate isolated strong convection is occurring elsewhere within 120 nm in the NW semicircle and within 150 nm in the SE semicircle. Fernanda has weakened slightly due to an ongoing eyewall replacement cycle, but is forecast to strengthen again during the next 24 hours or so before gradually weakening thereafter. A gradual turn toward the W-NW is expected later today, and this motion should continue through Sunday, with large swells spreading and expanding out ahead of Fernanda to the NW and W. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 for more details. An elongated area of low pressure is S through SW of Acapulco Mexico, with a likely developing low center near 14N99.5W at 1013 mb. This feature is associated with a tropical wave moving W at 10 kt across the area. Deep convection has persisted today, with scattered to locally numerous moderate to strong convection from 12N to 15.5N between 96W and 103W. The low is forecast to move generally W-NW during the next couple of days and has a medium chance of tropical cyclone formation within the next 48 hours. ...TROPICAL WAVES... A tropical wave extends N of 08N along 100W. Please refer to the Special Features section above for more details on the tropical wave and the associated elongated low pressure developing along the axis. A tropical wave is S of 16N along 111W/112W is moving W at 15 kt. The tropical wave is becoming less defined as it interacts with the outer circulation of Hurricane Fernanda which is located to the W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N76W TO 07.5N84W TO developing low pres near 14N99.5W TO 11N111W where it breaks approaching Hurricane Fernanda, then resumes from 08N127W TO 08N136W. The ITCZ extends from 08N136W to 07N140W. Scattered moderate to strong convection is occurring within 120 nm N and 180 nm S of the trough E of 90W, and from 06N to 12N between 110W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features for information on a broad area of low pressure S-W of Acapulco. The subtropical ridge continues to build in the wake of the rapidly weakening remnant low of Eugene well W of the region. This is allowing a tight enough pressure gradient to support moderate NW to N winds off the coast of Baja California peninsula, and will pulse to 20 kt over the next couple of late afternoons and evening. 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 to 3 ft seas will prevail in the Gulf of California, except 3 to 4 ft seas S of 23N towards the entrance to the Gulf. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, moderate offshore winds have diminished from this morning, but will pulse to fresh each night with nocturnal drainage through Tuesday morning, increasing fresh to strong thereafter. Gentle to moderate southerly winds are expected south of the monsoon trough axis. Long period cross-equatorial southerly swell and 6 to 7 ft seas will continue to propagate into the waters W of Colombia and Ecuador, with a reinforcing pulse of swell moving into the area this morning, reaching the Central America coast Saturday night and Sunday. Another and large set of southerly swell will move into the waters early next week. REMAINDER OF THE AREA... Please see the special features section for information on Hurricane Fernanda. The post-tropical remnant low of Eugene near 29N129.5W at 1018 mb is drifting northwest and gradually dissipating, with no discernible deep convection. Moderate to fresh NE winds on the N side of the low pressure will diminish this evening. 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. $$ Stripling