000 AXPZ20 KNHC 231543 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1349 UTC Fri Jun 23 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Shower and thunderstorm activity has begun to show signs of organization in association with a broad area of low pressure located a few hundred miles south-southwest of the Gulf of Tehuantepec. Environmental conditions appear conducive for development, and there is a medium chance this system will become a tropical depression by early next week while it moves slowly west-northwestward parallel to the coast of Mexico. The main impacts over the next several days will include heavy rainfall along the coast and inland between Puerto Angel and Cabo Corrientes, along with strong winds and building seas offshore. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to the developing low pressure near 13N97W to 08N125W. The intertropical convergence zone reaches from 08N125W to beyond 06N140W. Scattered moderate to isolated strong convection is noted from 09N to 14.5N between 92W and 100W. Scattered moderate convection within 60 nm south of axis between 115W and 120W. Scattered moderate within 60 nm south of axis between 135W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak 1015 mb high pressure remains centered near 26N122W. Ship observations indicate moderate to occasionally fresh northerly wind between the high pressure and the coast of Baja California Norte and the resident surface trough over the Gulf of California. A negatively tilted upper trough is migrating across the waters off Baja California Norte as well, supporting a few rare thunderstorms off Punta Eugenia overnight. Northerly swell to 8 ft had been moving into this same area but has been decaying since yesterday with 5 to 7 ft. Gentle to moderate northerly flow will persist off Baja California Sur with 4 to 6 ft seas. Gentle to moderate southerly breezes will persist over the Gulf of California with slight seas. See Special Features for more information on developing low pressure southwest of the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate southwest to west winds are expected across most of the region during the forecast period, with the exception of mainly S winds between Ecuador and the Galapagos Islands. Seas will subside to 4-5 ft during into early next week. REMAINDER OF THE AREA... A surface trough is digging into the region north of 28N between 125W and 130W. Moderate to fresh northwest winds are noted in recent scatterometer data between the trough and high pressure farther west. Otherwise weak high pressure is supporting gentle northeast winds across the area north of the convergence zone. Altimeter satellite data shows northerly swell of 8 to 12 ft north of 20N west of 120W, and 6 to 8 ft farther south. Seas will gradually subside through the upcoming weekend. $$ Christensen