Pacific Discussion

  • NHC East Pacific Tropical Weather Discussion
    by (nhcwebmaster) on September 23, 2023 at 2:53 PM

    000 AXPZ20 KNHC 231453 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Sep 23 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 1410 UTC. ...SPECIAL FEATURES... Central East Pacific Invest 97E: A 1009 mb area of low pressure is along a tropical wave near 119W, and is located several hundred nautical miles southwest of the southern tip of the Baja California peninsula near 13.5N119W. The low has changed little in organization during the past 24 hours. Numerous moderate scattered strong convection is within 90 nm in the SE semicircle and within 75 nm in the NW semicircle. Associated winds are currently 20-25 kt and seas are around 7-8 ft. Gradual development of the disturbance is still expected, and a tropical depression will likely form by early next week while the system moves generally westward across the central and western parts of the eastern Pacific basin. This area has a medium chance of tropical cyclone formation through 48 hours and a high chance through the next 7 days. Please read the latest NHC Tropical Weather Outlook at for more details. ...TROPICAL WAVES... A tropical wave is along 106W from 03N to 18N, moving W at around 10 kt. Scattered moderate isolated strong convection is noted from 04N to 14N between 100W and 110W, and from 17N to 19N between 108W and 110W. A tropical wave is along 119W from 04N to 19N, moving W at around 10-15 kt. Please read the Special Features section for nearby convection. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N75W to 07N95W to the above mentioned area of low pressure near 13.5N119W to 09N140W. Scattered to numerous moderate convection is noted from 01N to 09N between 77W and 80W, from 04N to 08N between 80W and 88W, from 02N to 08N between 93W and 100W, and from 04N to 12N between 120W and 137W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge dominates the offshore forecast waters of Baja California supporting moderate to fresh NW-N winds from near Punta Eugenia northward. Seas are 5-7 ft in NW swell offshore Baja California. Fresh N winds are noted in the Gulf of Tehuantepec. Winds are moderate or weaker elsewhere, with seas of 4-6 ft, except 1-3 ft in the Gulf of California. For the forecast, the surface ridge will remain in control of the weather pattern across the region into the start of next week. NW-N winds offshore Baja California will pulse to moderate to fresh from near Cabo San Lazaro northward, then fresh to strong starting Sun night. Fresh N winds will pulse in the Gulf of Tehuantepec through Mon, then fresh to strong Mon night through Wed night. Winds will be moderate or weaker elsewhere. Seas will not change much through Mon night, then will gradually build to 7-11 ft in NW swell offshore Baja California thereafter. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh offshore winds are noted over and downstream the Gulf of Papagayo, with seas of 4-5 ft. Seas are 2-4 ft elsewhere, except 4-6 ft offshore Ecuador to the Galapagos Islands. Light to gentle winds prevail elsewhere north of the monsoon trough, except moderate in the Gulf of Panama. South of the monsoon trough, gentle to moderate winds prevail. Deep convection persists from the Pacific coast of Colombia to offshore Panama. Higher winds and seas are possible there. For the forecast, moderate to fresh gap winds will prevail in the Gulf of Papagayo through early Sun. Elsewhere, winds will be moderate or weaker through the next several days. Slight to moderate seas will prevail, highest offshore Ecuador to the Galapagos Islands, where they may build slightly in S-SW swell by the middle of next week. ...REMAINDER OF THE AREA... Refer to the Special Features section above for details on an area of low pressure near 13.5N119W, which is along a tropical wave near 119W. The remnants of Kenneth are analyzed as a surface trough extending from 27N125W to 16N126W. No deep convection is evident with the remnants. Associated winds are moderate to fresh with remnant 8-9 ft seas in mixed swell, mainly on the NW side. Elsewhere, winds are mainly moderate or weaker. Seas are 5-7 ft elsewhere W of 100W, and 4-6 ft E of 100W. For the forecast, other than the broad area of low pressure along the tropical wave near 119W, the remnants of Kenneth will gradually dissipate while associated winds and seas diminish and subside. Elsewhere, weak high pressure will prevail N of the monsoon trough through the weekend with moderate or weaker winds. Looking ahead, a cold front may push just SE of 30N140W for the start of next week with strong high pressure building in across the waters N of the monsoon trough/ITCZ behind it by the middle of next week. This will result in moderate to fresh trades N of 10N and W of 120W. NW swell associated with the front will push into the northern waters early next week, building seas to 8-11 ft N of 10N and W of 115W by the middle of next week. Meanwhile, a set of southerly swell will build seas to around 8 ft NE of 03.4S120W by early next week, with seas of 7-9 ft S of 04N and W of 115W by the middle of next week. $$ Lewitsky