000 AXPZ20 KNHC 181605 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Apr 18 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough reaches from 08.5N84W TO 04.5N100W TO 10N107W. The ITCZ extends from 07N112W TO 02N132W TO 01.5N138W. Widely scattered to scattered moderate to strong convection is present from 02.5N to 09N between 81W and 103W...and within 180 NM N of ITCZ between 114W and 137W. Scattered to numerous moderate to strong convection is noted from 02S to 07S between 97W and 109W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weakening surface ridge extends from nw to se from 1020 mb high pressure centered near 26N126W to beyond the Revillagigedo Islands to near near 14N107W. Strong NW winds have developed on the east flank of the ridge along the Pacific coast of Baja from 28N to 32N, where seas have built to 6-8 ft this morning. The strong winds will spread southward over the EPAC waters to 26N late tonight, and then expand S and W across the EPAC waters to the N of 23N and e of 120W by Thu morning. Seas will gradually build 8 to 9 ft across this area by Thursday morning. Global models suggest that winds could reach 25-30 kt by Thursday morning across the Bay of Sebastian Vizcaino. The pressure gradient inducing these winds will begin to relax late Thu night through Friday as a cold front approaching 30N140W weakens the ridge. Moderate to fresh NW breezes on Fri morning will decline to only a gentle NW flow on Sat morning. Associated seas will subside to 5 to 7 ft by Sat night. Gulf of California: Gentle to locally moderate NW flow is generally expected through tonight. A moderate to fresh nw breeze will follow Wed through Sat with late afternoon heating leading to local enhancement of winds. Gulf of Tehuantepec: Fresh northerly drainage flow is expected late tonight through Wed morning, and again late Wed night through Thu morning. The next significant event northerly gap wind event is expected to begin on Sun night. Model guidance suggests strong to near gale force winds will occur Sun night through Monday morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to fresh nocturnal drainage winds are expected from the evening hours through late morning each of the next few days, with no significant gap wind events anticipated through the upcoming weekend. Gulf of Panama: Light and variable winds are expected this week with periods of southerly wind flow to prevail as low pressure dominates NW Colombia and the adjacent Caribbean. Light to gentle winds, and combined seas of 3 to 6 ft in mixing SW and NW swell will prevail elsewhere through the rest of the week. REMAINDER OF THE AREA... A surface high centered near 26N126W will shift n of 32N tonight. The high and associated middle atmospheric ridging continues to block the eastward progress of cold fronts that stall and dissipate over the NW waters. However, NW swell generated to the W of the fronts will propagate SE and cause seas to build to between 8 and 12 ft across the waters W of a line from 32N129W to 22N140W tonight. Expect seas of 8 to 10 ft W of a line from the central Baja Peninsula to 06N140W early on Thursday morning. Another pulse of NW swell will arrive at 32N140W on Thursday night ahead of a strong cold front. Strong to near gale force S-SW flow will precede the front across the discussion waters west of 135W from 28N to 32N on Thu night and Fri. $$ Stripling