000 AXPZ20 KNHC 170901 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Feb 17 2023 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: Strong high pressure will build southward along the eastern slopes of the Sierra Madre Mountains in Mexico in the wake of a cold front moving across the Gulf of Mexico. The pressure gradient between this building high pressure and lower pressure within the equatorial trough in the eastern Pacific will support the next gap wind event in the Tehuantepec region. Sustained gap winds reaching gale force are expected to start rapidly this morning and briefly increase to minimal storm force this evening. Storm- force winds will diminish back to gale-force early on Sat. Afterward, gale-force winds will persist across the area through Sun morning. Seas are forecast to peak to near 23 ft with this gap wind event tonight into Sat. Large seas generated from this strong gap wind event will spread well away from the Tehuantepec area, including the Guatemala and El Salvador offshore waters. Mariners transiting across or in the vicinity of the Gulf of Tehuantepec today into Sat should be aware of this upcoming gap wind event, and take the necessary action to avoid these hazardous marine conditions. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more information on this event. Pacific Significant Swell: A cold front is forecast to drop SSE over the northern waters through the upcoming weekend. Low pressure will develop along the frontal boundary and shift southward to near 29N by early Sun. The low is forecast to meander over the NE waters through late on Mon before dissipating. The pressure gradient between the low and high pressure to its W will usher in fresh to strong northerly winds. These winds may reach near gale-force speeds on Sat and Sat night. A new set of NW to N swell will follow behind the cold front. Latest Wave model guidance indicates that the swell is likely to generate seas of 11-15 ft at 10-15 seconds roughly N of about 25N and W of 129W on Sat and Sat night before subsiding on Sun. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N82W to 02N105W. The ITCZ continues from 02N105W to 04N140W. Scattered moderate convection is noted from 02N to 05N between 90W and 100W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Storm Warning is in effect for the Gulf the Gulf of Tehuantepec. Please see the Special Features section for information on this upcoming gap wind event. NW swell continues to propagate across the Baja California offshore waters, extending southward to the waters west of Cabo Corrientes. The swell is producing seas of 7-8 ft over these waters. Moderate to locally fresh NE winds are across the Baja offshore waters, while fresh to locally strong northerly winds are along the Gulf of California. Seas of 5-8 ft are in the central and southern sections of the Gulf, while seas of 3-5 ft are in the northern section. Gentle NW winds are over the southwestern Mexican offshore zones, with seas of 4-6 ft in a long-period NW swell. For the forecast, aside from the storm force gap wind event, strong high pressure over the Great Basin of United States will support fresh to strong NW to N winds across most of the Gulf of California through late this afternoon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong winds prevail across the Gulf of Papagayo and downwind to near 89W along with seas to 6 ft. Moderate to locally fresh N winds are in the Gulf of Panama, where seas are in the 4 to 5 ft range. Light to gentle winds are seen elsewhere along with seas of 4-5 ft primarily in long- period S to SW swell. For the forecast, fresh to strong NE to E winds in the Gulf of Papagayo region will persist through early today, and again Tue and Tue night. Strong to near gale-force winds and moderate to rough seas are expected each night through Mon. Fresh N to NE winds in the Gulf of Panama will increase to strong speeds Sat night through Sun night, reaching downwind of the Gulf to near 04N. The next significant Gulf of Tehuantepec gap wind event is expected to bring large W to NW swell over the Guatemala and El Salvador waters beginning tonight. REMAINDER OF THE AREA... Please see the Special Features section for information regarding upcoming significant seas in the western part of the area. High pressure prevails across the waters north of 20N. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ to the south supports an area of fresh to locally strong trades north of the ITCZ to 20N and west of 120W. Seas are 8-10 ft in long- period N swell. Elsewhere, winds are moderate or weaker with seas of 5-8 ft primarily in northerly swell. For the forecast, aside from the upcoming significant swell, fresh to strong NE to E trade winds are forecast to persist over the west-central waters through the upcoming weekend, with overall little change to seas within this part of the area. $$ AL