000 AXPZ20 KNHC 161605 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Thu Feb 16 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: Strong high pressure building across the eastern slopes of the Sierra Madre Mountains in Mexico will support the next gap wind event in the Tehuantepec region. Sustained gap winds reaching gale force are expected to start Fri morning and briefly increase to minimal storm force by Fri 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 24 ft with this gap wind event Fri night 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 Fri night 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from low pressure of 1008 mb that is over northwest Colombia southwestward to 07N81W to 03N90W to 02N100W to 02N108W, where scatterometer data indicates that it transitions to the ITCZ and continues to 04N120W to 05N130W and to beyond 04N140W. Scattered moderate to isolated strong convection is within 120 nm N of the the ITCZ between 106W-110W. Scattered moderate convection is within 120 nm N of the ITCZ between 132W-140W, also within 30 nm S of the ITCZ between 108W-110W. 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 more details. NW swell with a period of 10-14 seconds continues to propagate across the Baja California offshore and adjacent waters to near 130W. Moderate to locally fresh NE winds and seas of 8-11 ft are across the Baja offshore waters and are expected to subside tonight. Fresh to locally strong northerly winds are along the Gulf of California as supported by strong high pressure in the Great Basin. Similar winds, NE in direction, are funneling through mountains gaps and out over the adjacent Pacific waters. Seas of 5-7 ft are in the central and southern sections of the Gulf, while lower seas of 3-5 ft are in the northern section. Gentle to moderate NW winds are over the southwestern Mexican offshore zones, with seas of 5-6 ft due to a long-period NW swell. Otherwise, light to gentle winds are in the region of Tehuantepec along with seas of 4-6 ft due to a long-period S to SW swell. For the forecast, NW swell affecting the offshore forecast waters of Baja California will continue to propagate southward before subsiding below 8 ft tonight into early Fri morning. High pressure over the Great Basin of United States will continue to support fresh to strong NW to N winds across most of the Gulf of California through late Fri afternoon. These winds will continue to filter through the mountains gaps in Baja California into the Pacific offshore through late tonight. The next gap winds event in the Tehuantepec region is expected on Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong winds prevail across the Gulf of Papagayo and downwind to near 90W with seas to 7 ft. Moderate to locally fresh N winds are in the Gulf of Panama, where seas are in the 4 to 6 ft range highest S of the Azuero Peninsula. Light to gentle winds are seen elsewhere along with seas of 4-6 ft primarily due to a long-period S to SW swell. For the forecast, fresh to strong NE to E winds across the Gulf of Papagayo region will persist through Fri. Strong to near gale force winds and moderate to rough seas are expected at night Fri through Sun, with some possibility for these winds to reach gale-force. Winds will also increase at night in the Gulf of Panama and downwind to near 04N-05N Fri through Sun. The next strong Tehuantepecer gap wind event is expected to bring large W to NW swell over the Guatemala and El Salvador waters beginning Fri night. REMAINDER OF THE AREA... A ridge extends across the northern forecast waters covering roughly the region N of 12N W of 108W. 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, especially from 07N to 22N west of 118W. Seas are 8-10 ft due to a long-period N swell, with the highest of these confined from 07N to 11N and W of about 131W. Elsewhere, winds are moderate or weaker with seas of 5-8 ft primarily in northerly swell. For the forecast, fresh to strong trades are forecast to persist over the west-central waters the weekend. A cold front nearing 31N140W is forecast to drop SSE through the upcoming weekend as a broad and strong area of high pressure builds in behind it. In addition, a low is forecast to develop along the frontal boundary and shift southward to near 29N by early Sun. It is then forecast to meander over the NE waters through Sun night. The pressure gradient between the low and the strong high pressure to its W is likely to usher in fresh to strong northerly winds along with a new set of NW to N swell behind the front and WNW of the low. Presently, latest Wave model guidance indicates that NW to N well may produce seas of 11-15 ft N of 25N between 130W-140W on Sat and Sat night before subsiding on Sun. In addition, there is a chance for the fresh to strong northerly winds to reach near gale-force and to even gale- force speeds on Sat. $$ Aguirre