000 AXPZ20 KNHC 150854 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 910 UTC Tue Jan 15 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: Strong high pres N of the region building southward across eastern Mexico continues to support minimal gale force winds across the Gulf of Tehuantepec. Maximum winds are reaching near 40 kt, with associated seas to 14-15 ft. This gale force wind event is expected to continue through Wed morning, with strong northerly winds then continuing across the Gulf through Fri, pulsing to minimal gale force Wed and Thu nights. Winds will then diminishing temporarily Fri night as the high pres weakens and shifts E. NE swell in excess of 8 ft will propagate as far SW as 105W this morning. This swell will merge with longer period NW and SW swell through the next few days to produce a large area of seas 8 ft and greater well to the south of the Gulf, from 05N to 13N between 95W and 105W. For more information, see the East Pacific High Seas Forecast under WMO/AWIPS headers FZNT02 KNHC/HSFEP2. Looking ahead, a strong gale force to minimal storm force gap wind event is possible by Sun. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 04N77W to 03N85W. Segments of the ITCZ extends from 03N85W to 03N97W and from 04N102W to 07N125W to beyond 03N140W. No significant showers or thunderstorms are observed along the ITCZ. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak cold front reaching from Baja California Norte to 21N120W will drift eastward and dissipate through the morning across the Gulf of California and Baja California Sur. NW swell of 8 to 10 ft following the frontal boundary will continue to move into the offshore waters of Baja California and the Revillagigedo Islands through today. The NW swell will linger through mid week of Baja California. Looking ahead, strong high pressure will follow a another cold front moving into northern Baja California Norte by early Fri. This will support fresh to strong NW winds north of Punta Eugenia by late Fri. Reinforcing NW swell of 12 to 15 ft will also follow the front, moving into the offshore waters of Baja California late Fri and early Sat. Gentle to moderate flow will persist in the Gulf of California through mid week, increasing by late week in the wake of the cold front and as strong high pressure builds north of the area over the Great Basin. Meanwhile moisture will continue to stream ahead of a mid/upper trough along roughly 118W, bringing a few showers and thunderstorms across Baja California Sur, the southern Gulf of California, and into Sinaloa through this afternoon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Strong NE to E winds will prevail across the Gulf region. The strongest winds and greatest areal coverage downstream of the Gulf of Papagayo will be each night as nocturnal drainage flow augments the winds. Seas will peak around 9 ft downstream. Gulf of Panama: Moderate to fresh northerly winds will flow downstream to near 05N, with pulses to 20 to 25 kt mainly in the SW Gulf off the Azuero Peninsula. Accompanying seas will reach 6 to 8 ft. REMAINDER OF THE AREA... Strong high pressure centered north of the area near 36N131W, following a dissipating frontal boundary currently moving into Baja California Norte. A scatterometer satellite pass from 03 UTC indicated strong to near gale force SW winds south of the high pressure in the waters north of 28N between 125W and 135W. A concurrent altimeter satellite pass showed 12 to 15 ft seas in the area of strong winds. The combined seas are primarily ongoing NW swell, with 8 to 12 ft seas persisting over most of the area west of 110W. The strong winds will lift north of the are region over the next six hours, with the seas 12 ft or greater following within 24 hours. A second front will pass west of 140W into the discussion area by early Wed. The western portion of the front will stall then lift north of the area as a warm front Thu, leaving an eastern segment which will continue to move eastward toward Baja California by late week. Ridging will build along 25N mid to late in the week, supporting a broad area of fresh trade winds farther south into the tropics. A new round of large, long-period NW swell will move into the region mid to late week, with seas in excess of 12 ft, reaching as high as 19 ft during the middle portion of the week near 30N. Farther to the southeast, a scatterometer pass verified a surface trough along 100W from 02N to 08N, moving west at 10 to 15 kt. Fresh to strong east winds are noted on the northern periphery of the trough. A concurrent altimeter pass showed seas to 9 ft in the area of strong winds. This feature formed at the base of a negatively tilted mid/upper trough reaching into the deep tropics. The trough will continue to move west, reaching 120W by Fri. Winds and seas will diminish thereafter as the trough moves west of its upper support and weakens. In addition to the trough, the area from 04N to 15N between 95W and 110W will also see combined seas of 8 to 12 ft in a mix of long period NW swell and shorter period NE and E swell emerging out of the gap wind areas. $$ Christensen