000 AXPZ20 KNHC 160941 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 941 UTC Wed Jan 16 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A recent scatterometer satellite pass confirmed gap winds to minimal gale force were still active into the Gulf of Tehuantepec. This gale event is gradually diminishing as a large cool airmass north of the region modifies and shifts eastward, allowing gales to end later this morning. Near gale force winds will persist through the Gulf of Tehuantepec through early Fri, with the strongest pulses occurring overnight into the early morning. Seas 12 to 13 ft approximately 240 nm downstream of the Gulf will subside as the winds diminish, but will still build up to 11 ft overnight through early Fri. A relatively tranquil period will follow from mid Fri to late Sat, with minimal winds and seas. Looking ahead, a powerful cold front will move across the western Gulf of Mexico, through southern Mexico into the Gulf of Tehuantepec by Sat night. This will bring winds to storm force and very high seas through the Gulf of Tehuantepec by midday Sun. Marine interests transiting through the Gulf of Tehuantepec Sun into early next week should make precautions accordingly. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 02N79W to 04N90W. The intertropical convergence zone continues from 04N90W to 1010 mb low pressure near 05N106W to beyond 08N140W. Scattered moderate to isolated strong convection within 240 nm in the NE semicircle of the low pressure. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 1021 high pressure centered near 26N120W is maintaining light to gentle breezes off Baja California and the Gulf of California. Moderate N winds persist off Cabo Corrientes, and light breezes elsewhere off the Mexican coast outside of Tehuantepec. NW swell of 8 to 10 ft persists in the offshore waters of Baja California and the Revillagigedo Islands. A few showers and thunderstorms are active just west of Clarion Island, on the southeast side of a persistent mid/upper trough. Little change is expected until late Thu with the arrival of a weakening cold front into northern Baja California Norte. While the front will dissipate as it moves across Baja California and the Gulf of California through Fri, it will be accompanied by a new round long-period NW swell of 12 to 16 ft across the waters off Baja California. High pressure building behind the front will allow fresh to strong NW winds north of Cabo San Lucas late Fri into Sat. Over the Gulf of California, strong high pressure building over the Great Basin north of the area will support fresh to strong NW winds extending the length of the Gulf from Fri night through Sat. The strength, fetch and duration of the winds will be enough to support wave heights to 8 ft in the southern Gulf of California by Sat night. Winds and seas will diminish by Sun as the high pressure weakens and shifts east. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong high pressure north of the area will keep gap wind areas active through Fri and Sat. Fresh to strong gap winds persist as far as 300 nm to the W-SW of the Gulf of Papagayo through the next several days. Winds will occasionally pulse to near-gale force during overnight and early morning hours. Seas will build to 8 to 10 ft. Similarly fresh to strong northerly gap winds will impact mainly the western Gulf of Panama extending into the waters south of the Azuero peninsula. REMAINDER OF THE AREA... A scatterometer pass from around 05 UTC illuminated the circulation along the ITCZ near 05N106W, with an estimated pressure of 1010 mb. Fresh to strong easterly winds are noted within 270 nm north of the low pressure. A concurrent altimeter pass showed seas 8 to 10 ft in the area of strong winds. The low pressure will move westward along the ITCZ over the next several days, weakening to an open trough as it reaches 120W by early Fri. Farther northwest, fresh SW winds are noted on a 02 UTC scatterometer pass in the waters north of 28N west of 135W ahead of a cold front approaching from the west. The stronger winds will lift north of the area through today. Large long period swell with heights of 12 to 24 ft will follow the frontal boundary as it moves east. The leading edge of the front will continue eastward across the waters north of 28N through Thu, weakening Fri as it moves into Baja California. The front will leave a stalled segment along 28N, with the western portion of the front lifting north as a warm front through Thu. NW swell in excess of 15 ft will move eastward north of 25N into Fri. NW swell in excess of 12 ft will reinforce existing NW swell of 8 to 10 ft farther south over waters west of 120W through Fri. Looking ahead, a ridge will build by Sat across the waters north of 25N in the wake of the front. This will support a broad area of fresh trade winds farther south into the tropics, with fresh to strong winds developing ahead of the surface trough moving along the ITCZ. The ridge will weaken into Sun, allowing winds and seas to diminish somewhat across the tropics.. $$ Christensen