000 AXPZ20 KNHC 050948 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Jul 05 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURE... A tropical wave is analyzed from 09N116W to 20N116W with a 1007 mb surface low along the wave near 16N116W. This system has been moving W at about 8 kt over the past 48 hours. Currently scattered strong convection is observed within 120 nm SW of the the low. Several other cyclonic swirls are noted along the tropical wave axis. The pressure gradient is supporting fresh to strong NE winds within 150 nm over the NW semicircle. Fresh to locally strong southerly monsoonal flow, with seas to 8 ft primarily in southerly swell, is observed within 180 nm SE of a line from 16N116W TO 11N122W. Additional development of this system is possible over the day or so before it reaches colder waters, and a tropical depression could form while it moves W- NW. Expect the band of fresh to locally strong monsoonal flow currently SE of the low to shift W over the next 48 hours. ...TROPICAL WAVES... A tropical wave is analyzed to the N of 06N along 86W with scattered strong convection noted within 30 nm either side of a line from 12N88W to 14N92W. Additionally clusters of tstms are likely over Honduras, Guatemala and El Salvador today. A tropical wave is analyzed from 06N103W to 18N105W with scattered moderate convection observed s of 14N within 150 nm of the wave. Model guidance suggests that a surface low will develop long this wave near 10N in a day or so. Environmental conditions are favorable for gradual strengthening of this low. Please refer to the NHC Tropical Weather Outlook for the East Pacific at hurricanes.gov for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the Pacific coast of Costa Rica at 09N84W through the tropical wave at 10N105W to 10N110W where it loses identity. Scatterometer data indicates that the monsoon trough resumes again near 15N117W and continues SW to 10N130W to beyond 10N140W. Scattered moderate isolated strong convection is observed well S of the monsoon trough within 120 nm either side of a line from 07N78W to 08N86W, along the monsoon trough within 180 nm either side of a line from 07N91W to 12N103W, and within 150 nm either side of a line from 14N113W to 09N138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE orientated ridge axis extends into the offshore waters along 23N116W to 14N98W. Gentle to locally moderate NW flow, with 3 to 5 ft seas, are forecast W of the Baja Penisula through Thu morning. The pressure gradient will then tighten, with a moderate NW breeze W of Baja, except increasing to a fresh breeze N of 26.5N within about 60 nm of the coast Thu afternoon. A weak trough will pass E through the waters W of Baja on Sat accompanied by a light SW-W-NW wind shift. Seas will build to 6 to 8 ft in N swell across the waters N of 29N W of 118W on Sat. Moderate to fresh NE-E flow is expected across the waters S of 19N between 111W and 116W this morning in association with a surface low S of the offshore waters. Gulf of Tehuantepec...Strong N-NE drainage flow will continue across the gulf waters to along 14N between 95W and 96W through late morning. Strong N flow will develop again briefly tonight. Model guidance is suggesting gap events will occur again on Fri and Sat nights, with seas building to 8 ft. Gulf of California...A surface low will develop intermittently over the far northern gulf waters with a thermal trough meandering S from the low across the Baja Peninsula and gulf waters this week. A light to gentle, mostly southerly, breeze is expected this week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Moderate to fresh nocturnal NE-E flow is expected this week. Gentle to moderate southerly winds are forecast S of the monsoon trough which will extend E to W along roughly 09N. Long period SW swell in the form of 7 to 9 ft seas, will reach along the equator today, and reach along 04N on Thu, before beginning to subside. REMAINDER OF THE AREA... See special features and tropical wave paragraphs above. A N to S orientated trough extending from near 21N135W to 30N131W, will drift W today and Thu, and pass W of 140W early Fri, all the while accompanied by a gentle NE to E to SE wind shift. A NW to SE orientated ridge will then rebuild across the area. Long period southerly swell, in the form of 7-9 ft seas will cross the equator between 93W and 115W tonight, and reach along about 08N on Thu night before subsiding. $$ Nelson