000 AXPZ20 KNHC 091503 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1309 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 1200 UTC surface analysis and satellite imagery through 1445 UTC. ...SPECIAL FEATURES... Gulf of California Gale Warning: A cold front associated with a large and strong low pressure system forecast to develop over the SW U.S. will move S across the northern Gulf of California Tue night and then through central portions on Wed. As the front enters the northern Gulf Tue night, strong to gale force northerly winds will quickly blast into the far northern portions of the Gulf and spread southward to the Tiburon Basin by around sunrise before diminishing below gale force. Seas will quickly build to between 6 and 9 ft during this time. The front will then sweep S through central portions of the Gulf on Wed before dissipating across south portions Wed evening. N winds of 20 to 30 kt will spread S behind the front on Wed and cause seas to build to between 5 and 8 ft throughout the day. Winds and seas will diminish from N to S Wed night through Thu. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N82W to 08N87W to 06N91W to low pressure 1011 mb centered near 06N101W. The ITCZ continues from 06N101W to 04N109W to 06N118W to 05N130W to beyond 02.5N140W. Scattered moderate and isolated strong convection is present within 120 NM of a line from 08N82W to 05N89W to 06N98W and from 08N to 10N between 122W and 126W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad high pressure ridge extends SE from near 32N137W across the Baja California offshore waters to the Revillagigedo Islands. Large, long period NW swell continue moving through the regional waters to beyond the Revillagigedo Islands and are reaching Las Islas Tres Marias, producing seas of 8 to 10 ft across the Baja California offshore waters. The swell will large and dangerous surf along the coast of Baja California through Wed. The swell will gradually spread across the southern offshore waters to as far south as Puerto Angel through Wed, causing seas to build to between 6 and 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 NW of the region builds across the area waters. North of 28.5N, expect near gale force winds Tue night with seas building to 16 ft in mixed N swell. Strong NW winds and high seas of 9-12 ft will dominate the offshore waters Tue night through early Thu before gradually diminishing Thu and Fri. However, expected generally 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 this morning into Tue. Strong SW to W gap winds will develop Tue night over the northern Gulf ahead of the approaching cold front. Gulf of Tehuantepec: A narrow plume of strong northerly gap winds have developed across the Gulf of Tehuantepec overnight and are expected to continue into Tue, with seas building to 7-8 ft. These gap winds are expected to reach only 20-25 kt. 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 from varying directions with 4-6 ft seas will prevail in the Gulf of Papagayo region through Sat night. Onshore winds are forecast to prevail Tue night through Fri morning. 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 SW 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 weakening cold front extends over the NW waters from 30N127W TO 28N132W. A high pressure ridge extends SE toward the Revillagigedo Islands and is building across the area waters this morning. Fresh to strong winds are spreading behind the front, where seas are 9 to 11 ft. South of the ridge trade winds are also becoming fresh to strong, generally N of the ITCZ to the front and W of 130W. Recent satellite-derived sea height data suggests seas are running 9 to 11 ft in the trade wind belt in NW swell. Strong high pressure will continue to build across the region in the wake of the cold front and support a tightening pressure gradient across most of the waters N of 17N through Thu night. This will result in a large area of fresh to strong N to NE winds across this area through mid week. Near gale force N winds will develop just beyond the Baja California Norte offshore waters Tue night. Seas will build to between 12 and 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 winds to diminish Fri and into the weekend as high pressure weakens and moves westward. Long period NW swell continues to propagate SE across the Pacific high seas. This swell will cover most of the waters W of 100W by Wed morning. 8 to 10 ft seas will persist in a band roughly from 05N to 18N through Thu. The NW swell will begin to decay Fri and allow to area of 8 ft seas to retreat to N of a line from 24N114W to 07N130W to 05N140W by Fri night. Elsewhere, cross equatorial SW swell is entering the far southern waters and will mix with NW swell Tue and Wed to produce 8 to 9 ft seas generally S of 05N between 100W and 110W. $$ CAM