000 AXPZ20 KNHC 100239 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0235 UTC Wed May 10 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 0230 UTC. ...SPECIAL FEATURES... Tropical Storm Adrian centered near 9.5N 92.3W or 313 nm SW of San Salvador, El Salvador and 434 nm SSE of Salina Cruz, Mexico 10/0300 UTC, moving WNW at 6 kt. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Estimated minimum central pressure is 1005 mb. Numerous moderate and isolated strong convection is within 240 nm in the SW semicircle, 300 nm in the N quadrant, and 75 nm in the E quadrant. The tropical storm is forecast to gradually strengthen and is forecast to reach hurricane force Friday evening, while generally moving WNW. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N86W to near Tropical Storm Adrian to low pressure near 11N104W to 05N118W. The intertropical convergence zone axis extends from 05N118W to 04N130W to 05N140W. Scattered moderate and isolated strong convection is from 05N to 08N between 105W and 115W. Scattered moderate and isolated strong convection is within 300 nm in the N semicircle and 150 nm in the S semicircle of low pressure near 11N104W. Also, scattered moderate and isolated strong convection is from 07N to 09N between 80W and 84W. This convection developed over Panama during the afternoon heating hours before propagating offshore. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the special features section for information on Tropical Storm Adrian which is forecast to approach the offshore waters of the Gulf of Tehuantepec late in the week and into the weekend. Gentle to moderate W-NW winds prevail across most of the Gulf of California, except in the northern Gulf due to 1012 mb low pressure located near 31N114W. Moderate to fresh W-NW winds prevail N of 26N W of the Baja California Peninsula. Elsewhere, moderate NW winds generally prevail across the remainder of the forecast area NW of Manzanillo, except for fresh NW winds along the coast of Cabo San Lucas. Seas range from 5-8 ft range in NW swell across the offshore waters off of Baja California Norte, and generally 1-3 ft across the Gulf of California, except 3-4 ft near the entrance. Seas in the 4-7 ft range are noted elsewhere across the remainder of the forecast waters. Little change in marine conditions is expected through the end of the week. By Friday night into the upcoming weekend, the pressure gradient will increase offshore of southern California supporting increasing winds. These winds will build fresh NW swell of 8-11 ft into the offshore waters N of 25N during the weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See the special features section for information on Tropical Storm Adrian. Otherwise, mainly gentle to moderate onshore winds will prevail during the daytime hours, with gentle to moderate offshore winds during the overnight hours through the next several days. Combined seas of 4-7 ft will also dominate the waters through the remainder of the week and into the upcoming weekend. REMAINDER OF THE AREA... High pressure at 1027 mb centered just W of the discussion area near 31N143W extends a ridge axis SE to near the Revillagigedo Islands. The pressure gradient between this area of high pressure and lower pressure across the SW United States is supporting moderate to locally fresh trade winds across the open waters north of the ITCZ. Mixed northerly swell supports decaying combined seas of 7-10 ft across this same area. The area of high pressure will weaken during the next 48 hours as a cold front approaches the NW part of the discussion area Wednesday night, while a new weak high temporarily develops near 23N123W. The front will stall and dissipate from 30N132W to 28N140W by Thursday night. Stronger high pressure will build in the wake of the front increasing trades and resultant seas slightly by the end of the week and into the upcoming weekend. $$ LEWITSKY