000 AXPZ20 KNHC 070915 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon May 07 2018 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 0915 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec gale warning: Minimal gale force winds expected to persist until mid morning. Seas are forecast at a maximum of 12 ft downstream of the gulf waters near 15N 95.5W at sunrise. The pressure gradient will relax this afternoon, with near gale winds then continuing through sunrise on Tue. The gap event should end by late Wed morning with winds diminished to 20 kt or less. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends west from the Pacific coast of Colombia at 06N77W to 08N90W to an embedded surface trough that extends north to south from 05N to 13N along 115W. Scatterometer winds indicate an ITCZ develops west of the surface trough at 08N116W and extends west to beyond 07N140W. Scattered moderate isolated strong convection is observed within an area bounded by a line from 05N85W to 05N83W to 15N104W to 05N85W, and in clusters along the coast Central America and Mexico within 60 nm of 10.5N86W, 14N92W and 17N102W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Refer to special features section for a warning across and downstream of the Gulf of Tehuantepec. A northwest to southeast ridge will meander from near 21N116W to 15N106W through Tue, then retract north-westward as a tropical low develops well south of the Mexican offshore waters. Moderate northwest flow will continue across the waters west of the Baja California Peninsula through tonight. A tightening pressure gradient will increase the northwest flow to a fresh breeze, accompanied by 8 to 11 ft seas, across the waters from 29N to 32N west of Baja Norte on Tue with locally strong winds forecast on Wed into Thu. This northwest swell will propagate as far south as 25.5N on Thu before beginning to subside from the south. Gulf of California: Light, mostly southerly flow forecast through the middle of the week, except moderate nocturnal drainage flow expected near gap areas. Guidance is suggesting fresh to strong southerly flow along 30.5N on Fri and Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh nocturnal winds are expected through Tue night. Gulf of Panama: Light to gentle northerly nocturnal flow is forecast through the middle of the week. REMAINDER OF THE AREA... A surface high is centered near 32N128W with a quasi-stationary ridge extending southwest to beyond 22N140W. A weakening cold front will move into the far northwest waters this morning with strong southerly flow, and 6 to 8 ft seas, preceding the front across the discussion waters north of 29N overnight. Although the front will stall and wash out from near 32N131W to 23N140W by late Tue, large seas of 10 to 16 ft are expected west of the front today. These large seas will quickly subside to 6 to 9 ft west of a line from 32N128W to 17N140W on Tue night. The seas will further subside to less than 8 ft across the tropics during the middle of the week. Seas of 8 to 11 ft are forecast across the subtropics, generally north of 24N east of 124W late in the week. A broad and convectively active surface trough, or easterly wave is embedded in the monsoon trough/ITCZ near 114W. Model guidance suggests continued slow development to a tropical low near 10N121W perhaps as early as Tue. A blend of global guidance results in a solution of a surface low near 12N122W on Wed accompanied by strong winds. The low should continue northwest reaching near 14N123W on Fri and then accompanied by near gale force winds and seas of 10 to 15 ft. $$ Nelson