000 AXPZ20 KNHC 260921 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Feb 26 2020 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 Storm Warning: The next gap wind event over the Gulf of Tehuantepec is expected to commence this afternoon 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 very tight pressure gradient over the area, and bring an increase in winds funneling into the Gulf of Tehuantepec. Winds will rapidly increase to gale force by late afternoon, then to storm force this evening. Storm conditions are forecast to persist into early Fri, and the gale force winds are expected to continue into early Sun. Seas are forecast to build to 21-23 ft with this upcoming event by late tonight. Marine interests transiting across or in the vicinity the Gulf of Tehuantepec should be aware of this very strong gap wind event, and take the necessary action to avoid these hazardous marine conditions. Gulf of California Gale Warning: The pressure gradient between a surface ridge west of the Baja California peninsula and a trough over western Mexico is supporting fresh to strong NW-N winds across the Gulf of California. Strong high pressure building across the Great Basin region of the U.S. today will help to strengthen winds over the entire Gulf of California. Winds are forecast to increase to 20 to 30 kt, with seas building to 8 to 10 ft mainly S of 28N, with winds forecast to reach minimal gale force mainly in the central Gulf later this morning into the early evening. Fresh to strong winds will also affect most of the Baja California peninsula, but particularly the northern part where gale force gusts may occur near and just onshore. Winds are forecast to diminish to 20 to 25 kt across the Gulf of California by Thu morning with 8-9 ft seas S of 28N, with winds then diminishing to 20 kt or less by Thu afternoon. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03/HSFEP2 NHC or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N83W to 03N90W to 03N104W. The ITCZ continues from 03N104W to 05N140W. No significant convection is noted at this time. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about the developing storm warning in the Gulf of Tehuantepec, and the developing gale warning in the Gulf of California. Elsewhere, high pressure prevails over the offshore waters west of the Baja California peninsula, supporting moderate to fresh NW to N winds. NW swell propagating across the waters W of Baja California has reached the Revillagigedo Islands with seas of 6- 8 ft. Seas will start to subside south of Cabo San Lazaro today. As winds increase in the Gulf of California, fresh to near gale force N-NE winds are expected to bleed through the passages in Baja California Norte into the offshore waters north of Cabo San Lazaro, and gale force gusts may occur near and just onshore. This will maintain 8-11 ft seas there through early Thu. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Large NW swells generated by a developing storm force gap wind event in the Gulf of Tehuantepec will propagate into the waters of Guatemala and El Salvador by early Thu and continue into the upcoming weekend before subsiding Sun. Seas will reach to 16 ft along the offshore boundary between Guatemala and Mexico. Gulf of Papagayo: Mainly light and variable winds and 4-6 ft seas in mixed swell prevail at present. High pressure building north of the area by the end of the week will increase offshore winds to moderate to fresh on Thu, becoming fresh to strong Thu night. Strong to near gale force winds are then expected on Fri, possibly reaching minimal gale force during the upcoming weekend. Gulf of Panama: Mainly moderate northerly winds will increase to fresh to strong across the Gulf of Panama and downstream to near 04N or 05N beginning on Fri as high pressure builds north of the area. Winds will continue to pulse through the upcoming weekend. Elsewhere, gentle to moderate winds and seas of 4-6 ft in mixed, long period swell will prevail the remainder of the week. REMAINDER OF THE AREA... Seas of 8 ft or greater prevail over much of the forecast waters W of 112W in a broad mix of swell. Incoming long period NW swell will reach the NW waters today and spread SE, with seas peaking around 11-12 ft over the far NW waters by tonight. A ridge extends from high pressure centered north of the area near 37N132W to near the Revillagigedo Islands. The pressure gradient between this area of high pressure and lower pressure near the ITCZ is supporting fresh trade winds north of the ITCZ to 20N and W of 125W. Seas in the 8-10 ft range prevail across this area in mixed NW swell and NE wind waves. High pressure will begin to weaken today, but broad troughing along the ITCZ will maintain the pressure gradient, resulting in an area of fresh to strong trades by this evening, from 08N to 15N between 123W and 135W. Looking ahead, stronger high pressure will build NW of the area this weekend, with a large area of fresh to strong trades developing over the west-central waters. $$ Mundell