000 AXPZ20 KNHC 272150 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Oct 27 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 2145 UTC. ...SPECIAL FEATURES... Tropical Storm Selma centered near 11.7N 89.4W 1005 mb or about 140 MILES S of San Salvador El Salvador at 27/2100 UTC moving N- NW, or 345 degrees AT 06 KT. Maximum sustained winds are 35 kt with gusts to 45 kt. Numerous strong convection is currently observed within 90 nm over the SW quadrant, surrounded by scattered moderate isolated strong convection elsewhere within 300 nm over the SW quadrant of the center. Selma is forecast maintain minimal tropical storm strength through landfall near 13.6N 89.8W on Sat, weaken to a remnant low inland near 14.8N 89.5W on Sat night, and dissipate on Sun. Heavy rainfall is possible across El Salvador, southern Guatemala, southern Honduras and far western Nicaragua over the next couple of days. Refer to the latest forecast advisory under WMO/AWIPS headers WTPZ25 KMIA/MIATCMEP5 for additional details. Gulf of Tehuantepec Gale Warning: Strong N winds will develop in the Gulf of Tehuantepec late tonight, and increase to minimal gale force during the mid morning on Sat, with gale conditions then persisting through Sat evening. Seas will build to 16 ft downstream of the gulf waters near 14.5N95.5W on Sat evening. Near gale force northerly winds will persist throughout Sun, then diminish to strong N-NE winds on Sun night, finally diminish to less than 20 kt on Mon morning. Heavy Surf Conditions: Seas of 8 to 10 ft, with 20 to 24 second wave period, are forecast to reach the Pacific coast of the Baja Peninsula on Sat night, and reach the Pacific coast of Mexico as far S as 19N late Sun night. Refractive swell at 15 to 17 seconds will arrive across the southern Gulf of California on Sun. The surf energy in these breaking waves may produce dangerous near shore conditions including rip currents and beach erosion. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W from the Caribbean coast of NW Colombia at 09N77W to the Pacific coast of Costa Rica at 09N84W to 10N88W where the monsoon trough loses identity in the broad cylonic circulation associated with tropical Storm Selma. Scatterometer winds indicate that the monsoon trough develops again SW of Selma at 10N92W and continues SW to 09N96W, then turns NW to 11N104W, then turns SW to 09N115W, then NW again to 11N127W to beyond 11N140W. Scattered moderate isolated strong convection is observed to the N of 03N E of 80W, within 60 nm of 09.5N86W, within 75 nm either side of a line from 10N95W to 05N100W, within 90 nm either side of a line from 15N98W to 13N101W to 14N106W, within 90 nm either side of a line from 07N114W to 14N134W to 09N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Heavy Surf Conditions: please refer to the special features section above for information on heavy seas arriving this upcoming weekend. Gulf of Tehuantepec: please refer to the special features section above for information on a weekend gale event. Gulf of California: A moderate NW breeze is forecast on Sat. Light and variable winds expected on Sun becoming a moderate to locally fresh southerly breeze across the gulf waters N of 28N on Mon into Tue. A surface ridge extends E across the waters W of the Baja Penisula, with a moderate NW breeze forecast on Sat. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Tropical Storm Selma: please refer to the special features section above. Otherwise, moderate southerly winds, and 5 to 8 ft seas across the area are forecast to subside to 4 to 7 ft late Sat night. REMAINDER OF THE AREA... A 1019 mb surface high near 23N132W will gradually shift N through Sat with a broad ridge dominating the EPAC waters N of 12N W of 115W accompanied by gentle to moderate anticyclonic flow. Moderate to locally fresh SE flow will set up across the far NW waters on Sat. Long-period NW swell, in the form of 8 ft seas, has moved into the far NW waters. Expect seas of 8 to 13 ft W of a line from 32N123W to 13N140W midday on Sat, before beginning to subside. However, the swell field in the form of 8 to 11 ft seas, will continue to propagate SE across the waters W of a line from 32N117W to 22N115W to 03N140W on Sun, and across all waters W of 110W on Mon. $$ Nelson