000 AXPZ20 KNHC 190305 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 052 UTC Sat Jan 19 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 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N77W to 04.5N92W. The ITCZ continues from 04.5N92W to 01N104W to 01N111W to 04N119W. It then resumes from 05N122W to 04N140W. Scattered moderate isolated strong convection was noted from 03N to 13N between 108W and 116W. ...SPECIAL FEATURES... Gulf of Tehuantepec storm warning: The next gap wind event over the Gulf of Tehuantepec is expected to start Sat night as a strong cold front moving across the Gulf of Mexico reaches the isthmus of Tehuantepec. High pressure building behind the front will provide a tight gradient over the area, and bring an increase in winds funneling into the Gulf of Tehuantepec. Winds will rapidly increase to near gale force Sat evening, and reach gale force later Sat night. Winds will further increase to storm force Sun. Winds will diminish below storm force Sun night, and below gale force Mon. Seas will peak near 25 ft on Sunday during the period of storm force winds. Swell generated from this event will produce a large plume of 12 ft seas that will extend as far as 700 NM SW of the Gulf of Tehuantepec by Mon. Marine interests transiting through the Gulf of Tehuantepec Sat night into early next week should be aware of this upcoming gap wind event, and take necessary action to avoid hazardous marine conditions over the affected waters. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 for further details. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features for more details on the upcoming storm force gap wind event in the Gulf of Tehuantepec. Elsewhere, moderate to fresh north to northwest winds are along the offshore waters off Baja California. Long period NW swell is producing seas of 13 to 15 ft over the waters off Baja California Norte. This swell will bring dangerous surf and large breaking waves across portions of Baja California Norte through Sat. Seas in the 8 to 13 ft range prevail over the remaining open waters. The swell will slowly subside through the weekend, subsiding below 8 ft by late Sun night. A new set of NW swell will once again propagate into the offshore waters of Baja California Norte Mon. This swell will spread across the remainder of the offshore waters of Baja California through the middle of next week. Gulf of California: High pressure building over the Great Basin north of the area will support fresh to strong northwest winds extending the length of the Gulf through Sat. The strength, fetch and duration of the winds will 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 to the east. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient between high pressure north of the area and the equatorial trough will maintain strong gap winds across Papagayo and Panama through early Sat. Gap winds will diminish Sat and Sat night as high pressure north of the region shifts eastward ahead of a cold front, and helps weaken the pressure gradient. New high pressure will build in the wake of the cold front, supporting another round of even stronger gap winds through the Gulfs of Papagayo and Panama. Winds to gale force are possible through the Gulf of Papagayo Sun night into Mon. REMAINDER OF THE AREA... High pressure of 1026 mb is centered near 28N127W. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh to strong tradewinds N of the ITCZ to 20N and W of 120W. The ridge will weaken Sun, allowing winds and seas to diminish across the tropics. Long period NW swell continue to dominate the region, with seas 8 ft or greater covering the waters W of 105W. Seas will slowly subside through the weekend, falling below 8 ft over 20N. S of 20N, seas of 8 to 9 ft will persist into next week south of about 20N and west of 120W due to a a mix of northwest swell and remaining windwaves from local trade winds. $$ AL