000 AXPZ20 KNHC 280236 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Oct 28 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Tropical Storm Selma centered near 12.3N 89.0W 1005 mb, or about 100 miles S of San Salvador El Salvador at 28/0300 UTC moving N, or 010 degrees AT 06 KT. Maximum sustained winds are 35 kt with gusts to 45 kt. Scattered moderate isolated strong convection is observed within 240 nm over the SW quadrant of the center. Selma is forecast maintain minimal tropical storm strength through landfall early Sat near 13.4N 89.1W, weaken to a remnant low inland on Sat night, and dissipate on Sun. Heavy rainfall is still 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 overnight, and increase to minimal gale force early Sat morning, 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, and 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 enter 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 Pacific coast of Colombia at 08N77W across the Gulf of Panama to 07N81W, then turns NW to 09.5N87W 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 08N96W to 09N102W to 08N113W, then NW to 09N123W where scatterometer winds indicate a transition to an ITCZ which continues NW to beyond 12N140W. Scattered moderate isolated strong convection is observed to the S of 03N E of 79W, within 90 nm either side of a line from 07N79W to 10N86W, within 150 nm either side of a line from to 15N103W and within 120 nm either side of a line from 11N125W to 16N135W. ...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 1018 mb surface high near 25N132W will gradually shift N through Sat with a broad ridge dominating the EPAC waters N of 12N W of 115W and 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 20 to 24 second NW swell, in the form of 8 to 11 ft seas, has moved into the far NW waters. Expect seas of 8 to 13 ft W of a line from 32N118W to 16N125W to 09n140W late 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