000 AXPZ20 KNHC 090251 CCA TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 250 UTC Tue Oct 9 2018 Corrected Sergio information 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 0300 UTC. ...SPECIAL FEATURES... Hurricane Sergio centered near 16.0N 128.6W at 09/0300 UTC or 1130 nm WSW of the southern tip of Baja California moving N at 3 kt. Estimated minimum central pressure is 978 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Numerous moderate and isolated strong convection is noted within 150 nm of the center. Large swells associated with Sergio will continue to mix with long period NW swell creating confused seas across a large portion of the discussion waters, with the swell also continuing to impact the coast of Mexico the next several days as Sergio makes its way into central Baja California Sur by Fri. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for more details. Earlier scatterometer passes indicated continuing moderate to fresh SW flow into northern Central America and southern Mexico. This could produce heavy rainfall across Honduras, El Salvador, Guatemala, and southern Mexico into mid week. These rains may cause flash floods and mudslides in areas of mountainous terrain. The heavy rainfall threat is expected to shift northward during the next day or so as the SW lifts north and weakens. Refer to your local meteorological service for specific information on this potentially dangerous weather pattern. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough reaches from the Mexican state of Chiapas near 16N93W to 09N110W. Another segment of the monsoon trough reaches from 11N130W to 06N140W. Scattered moderate convection within 90 nm south of the monsoon trough east of 105W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on Hurricane Sergio. Mainly moderate to fresh NW to N winds and mixed swells from Sergio as well as long period NW swell will support combined seas of 7 to 11 ft west of 110W for the next couple of days. Light to gentle onshore winds and seas of 5 to 8 ft in mixed southerly and westerly swell will prevail east of 110W. Conditions are forecast to rapidly deteriorate across the Baja California waters as Sergio moves closer on Thu. Conditions will deteriorate for the central and northern Gulf of California Thu night. Winds and seas rapidly diminish Fri into early Sat as Sergio dissipates far inland. Farther south, the persistent SW flow has been supporting scattered moderate showers and thunderstorms extending around 1000 nm W-SW of the Guatemala and Chiapas coasts. The persistent SW flow is flowing across the isthmus into the northwest Caribbean and southern Gulf of Mexico where Hurricane Michael is active. As Michael moves northward through the next couple of days, the SW flow over the eastern Pacific will diminish slightly and shift northward into only southern Mexico and persist through the remainder of the week. Recent altimeter passes have indicated seas of at least 9 ft, although wave guidance suggests seas may be as high as 11 ft in the plume of persistent SW flow. These seas will subside slightly over the next couple of days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please refer to the Special Features section for additional details regarding the heavy rainfall potential for Central America. Fresh SW monsoonal flow and 8 ft seas will persist off Guatemala into mid week then will shift north of the area. Moderate SW flow will persist through the week. Long period SW swell will propagate into the waters off southern Central America, with combined seas building to 8 or 9 ft off Panama and Costa Rica by Thu. REMAINDER OF THE AREA... Please see the Special Features section for details on Hurricane Sergio. Outside of the influence of Sergio, moderate to fresh trades will prevail. The pressure gradient will lessen across the waters north of 20N and W of 120W during the second half of the week as high pressure centered NW of the discussion area weakens. Meanwhile, confused seas are likely to continue due to long period NW swell along with mixed shorter period swell generated from Sergio. Conditions are likely to improve by the end of the week after Sergio makes landfall. Long period SW swell arriving from the Southern Hemisphere will also contribute to combined seas and maintain sea heights around 9 ft along the equator between 100W and 130W late in the of the week. $$ Christensen