000 AXPZ20 KNHC 082139 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2135 UTC Mon Apr 8 2019 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of California Gale Warning: A cold front is expected to move southward across the Gulf of California Tue night. Model guidance has trended stronger with the post-frontal northerly winds over the northern Gulf as strong high pressure builds into the region. A brief period of gale force winds appears increasingly likely over the far northern Gulf late Tue night, and so a gale warning has been issued. Seas will build to 8-9 ft north of 30N by early Wed morning, then subside as wind speeds diminish over the northern Gulf on Wed. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 10N86W to 04N100W. The ITCZ begins near 04N100W and continues to 06N115W to 04N130W to beyond 03N140W. Scattered moderate convection is noted from 06N to 08N between 86W and 89W and also from 06N to 08N between 128W and 131W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad high pressure ridge extends southeastward across the Baja California offshore waters to just beyond the Revillagigedo Islands. The pressure gradient between this ridge and lower pressure over inland Mexico is likely producing moderate northerly breezes across the Baja California waters. Large, long period NW swell moving through the regional waters has reached the Revillagigedo Islands and is producing 8-10 ft seas over the offshore waters north of Cabo San Lazaro, and 6-9 ft seas as far southward as Cabo San Lucas. This swell will continue producing dangerous surf conditions along the coast of Baja California tonight. The swell will gradually spread across the southern offshore waters to as far south as Puerto Angel through Wed with seas of 6-8 ft. Looking ahead, winds are expected to strengthen to 20-25 kt over the offshore waters north of Cabo San Lazaro Tue through Wed as strong high pressure builds northwest of the region. Seas will build to 12-15 ft over the waters north of Punta Eugenia on Tue night in mixed swell. Wind speeds will gradually diminish by late week but generally remain fresh north of Cabo San Lazaro through Fri. Gulf of California: Please see the Special Features section above for more information about the gale warning in effect for the northern Gulf of California on Tue night. Recent scatterometer data showed moderate to locally fresh NW to N winds over the central Gulf of California. Winds will diminish to gentle speeds by Tue as the pressure gradient weakens. Strong SW to W gap winds will develop Tue night over the northern Gulf ahead of an approaching cold front. Behind the front, fresh to strong NW winds will develop across the central and southern Gulf Wed and Wed night as strong high pressure builds into the region. Seas will build to 5-7 ft across the central portions Wed afternoon, then subside late in the week as the pressure gradient relaxes. Gulf of Tehuantepec: Strong N gap winds are expected to funnel through the Chivela Pass and across the Gulf of Tehuantepec late tonight into Tue. These gap winds are expected to remain well below gale force. Fresh to strong N winds will pulse in the Gulf again on Tue night into early Wed, then diminish to light to moderate speeds for the rest of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Light to moderate winds with 4-6 ft seas will prevail in the Gulf of Papagayo region through Sat night. Gulf of Panama: Light to gentle breezes will prevail across the Gulf of Panama region this week with seas generally ranging from 4-6 ft. Elsewhere, light to gentle winds will persist through the week. Wave heights between Ecuador and the Galapagos Islands will build to 5-7 ft tonight as cross equatorial, long period SW swell moves into the region. SW swell will continue impacting the southern waters this week, mixing with NW swell later in the week. REMAINDER OF THE AREA... Long period NW swell continues to propagate SE across the Pacific high seas. This swell will cover most of the waters west of 105W by Tue with seas ranging from 8-11 ft, highest west of 125W. Elsewhere, cross equatorial SW swell continues moving across the far southern waters and will mix with NW swell on Tue to produce 8-9 ft seas south of 00N and west of 100W. A cold front extends across the far NW portion from 30N135W to 27N140W. A 1027 mb high pressure center near 29N131W maintains a ridge axis extending SE toward the Revillagigedo Islands. Mainly moderate to fresh trades cover the waters ahead of the front and north of the ITCZ to the south of the ridge based on recent scatterometer data. An earlier altimeter pass in this region showed 8-11 ft seas within the trade winds with the highest seas roughly from 08N to 15N between 125W and 130W. Strong high pressure building in the wake of this front will support a tightening pressure gradient across the waters Tue through Thu night. This will result in a large area of fresh to strong N to NE winds across much of the region north of 18N through midweek. Near gale force N winds will develop just beyond the Baja California Norte offshore waters Tue night. Seas will build to 12-16 ft across this region Tue night and persist into Wed night as NW swell mixes with S swell and NE wind waves. Expect wind speeds to diminish Fri and into the weekend as high pressure weakens and moves westward, allowing the pressure gradient to relax. $$ Reinhart