000 AXPZ20 KNHC 090241 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0240 UTC Tue Apr 9 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Gulf of California Gale Warning: A cold front is expected to move southward across the Gulf of California Tue night into Wed. The latest 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 is likely over the far northern Gulf of California late Tue night, and a gale warning remains in effect. 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 10N85W to 06N98W. The ITCZ begins near 06N98W and continues to 06N120W to beyond 02N140W. Scattered moderate convection is noted from 06N to 08N between 83W and 88W and also from 09N to 11N between 116W and 119W. ...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. Large, long period NW swell moving through the regional waters has reached the Revillagigedo Islands and is likely producing 8-10 ft seas over the Baja California offshore waters based on earlier altimeter data. This swell will continue to produce 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. Winds will 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. North of 29N, expect near gale force winds Tue night with seas building to 16 ft in mixed swell. Wind speeds will gradually diminish by late week but generally remain fresh north of Cabo San Lazaro through Fri night. Gulf of California: Please see the Special Features section above for information about the gale warning in effect for the northern Gulf of California on Tue night. Generally light to moderate winds will prevail over the Gulf overnight into Tue. 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 by Wed night, then subside later in the week as the pressure gradient relaxes. Gulf of Tehuantepec: Strong northerly gap winds are expected to funnel through the Chivela Pass and across the Gulf of Tehuantepec late tonight into Tue with seas building to 8 ft. 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. Seas will build to 5-7 ft Wed night into Thu in mixed SW and NW swell. Elsewhere, light to gentle winds will persist through the week. Wave heights between Ecuador and the Galapagos Islands will generally remain 5-7 ft through Fri as cross equatorial, long period SW swell moves into the region. Further offshore, seas will peak around 8 ft by midweek SW of the Galapagos Islands. REMAINDER OF THE AREA... A cold front extends over the NW waters from 30N132W to 27N140W. A high pressure ridge extends SE toward the Revillagigedo Islands. Earlier scatterometer data showed moderate to fresh trades over the waters ahead of the front and north of the ITCZ to the south of the ridge. A recent altimeter pass in this region showed seas to 12 ft within an area of enhanced trades near 15N137W. These seas are likely a combination of mixed S and NW swell with shorter period NE wind waves. Strong high pressure building in the wake of the cold front will support a tightening pressure gradient across the northern 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 remain 12 ft or greater through Thu 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. Long period NW swell continues to propagate SE across the Pacific high seas. This swell will cover most of the waters west of 100W by Wed morning with 8-10 ft seas in a band roughly from 05N to 18N. Elsewhere, cross equatorial SW swell is moving across the far southern waters and will mix with NW swell Tue and Wed to produce 8-9 ft seas generally south of the equator and west of 100W. $$ Reinhart