000 AXPZ20 KNHC 082201 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1915 UTC Mon Oct 8 2018 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 2045 UTC. ...SPECIAL FEATURES... Hurricane Sergio centered near 15.7N 128.5W at 08/2100 UTC or 1135 nm WSW of the southern tip of Baja California moving NNW 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 180 nm of the center. Scattered moderate and isolated strong convection is seen elsewhere between 12N and 19N between 121W and 132W. 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. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for more details. Enhanced SW monsoon flow driven by a broad area of low pressure, called a Central American Gyre, has already brought abundant moisture into portions of Central America. This could produce heavy rainfall across Nicaragua, Honduras, El Salvador, and the adjacent coastal waters for the next couple of days. 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 Gyre lifts N 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 12N98W to 09N110W. The trough resumes from 11N132W to 09N136W to beyond 08N140W. Scattered moderate and isolated strong convection is evident in an area bounded by 12N87W to 07N109W to 11N108W to 17N99W to 12N87W. Scattered moderate convection is also occurring from 07N to 09N between 126W and 135W and from 05N to 07N W of 137W. ...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. 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 to 10 ft seas are expected over the offshore waters roughly from 07N to 15N between 90W and 110W during the next couple of days, in response to the weakening Central American Gyre discussed previously in the Special Features section above. These conditions will gradually improve thereafter. Gentle to moderate SW flow with 4 to 6 ft seas will prevail for the waters of Panama and Costa Rica. 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, and a large and expanding area of mixed swell associated with Sergio. Conditions are likely to improve by the end of the week as Sergio moves E of 120W. Long period SW swell arriving from the Southern Hemisphere will also contribute to combined seas and maintain sea heights around 8 ft along the equator between 100W and 130W during the second half of the week. $$ CAM