000 AXPZ20 KNHC 120359 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Sep 12 2022 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 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from the coast of Costa Rica near 11N86W to 15N96W to a 1010 mb low near 18N106W to 11N114W to 13N130W to beyond 13N140W. Scattered moderate to isolated strong convection is noted from 04N to 16N between 80W and 100W and from 14N to 18N between 104W and 108W. Scattered moderate convection is noted from 06N to 13N between 102W to 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The remnant low of former tropical cyclone Kay is analyzed near 29N122W, just west of the Baja California offshore waters, with a central pressure of 1009 mb and is drifting south. Moderate to locally fresh winds are along the low, mostly in the western semicircle. Seas are 6-7 ft north of 27N between 121W and 128W. The low is forecast to continue to weaken as it slowly moves south through tonight. It will drift south- southeastward Mon and Mon night and weaken to a trough west of Baja California Tue. Light to gentle variable winds are noted elsewhere across the offshore waters of Baja California and in the Gulf of California. Earlier ASCAT data depicts an elongated southeast to northwest orientation of the cyclonic turning of winds over and to the south and southwest of the Gulf of Tehuantepec region. An area of moderate to locally fresh east- southeast winds are noted along and to within 90 nm offshore the coast of Guerrero. Fresh northerly winds are likely occurring in the Gulf of Tehuantepec. Seas are generally 6-7 ft across the Mexico offshore waters with 1-3 ft in the Gulf of California. Abundant deep layer tropical moisture is leading to numerous clusters of scattered moderate to isolated strong convection over the majority of the offshore forecast waters across the southwest Mexico offshore waters. Numerous thunderstorms are moving across the Gulf of Tehuantepec and portions of the Oaxaca offshore waters. For the forecast, the light to gentle variable winds over the offshore waters of Baja California Sur will increase to moderate by Tue as high pressure begins to build again across the region. Disorganized showers and thunderstorms extending from the Gulf of Tehuantepec westward along the southern coast of Mexico are associated with a trough of low pressure. This system is forecast to merge with another disturbance located farther west, and environmental conditions are expected to be conducive for gradual development over the next several days. A tropical depression is likely to form by the middle to latter part of this week while the system moves slowly westward near the coast of southern and southwestern Mexico. This system has a low chance of formation in the next 48 hours and high chance in the next 5 days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds are noted across the central American offshore waters. Gentle to locally fresh winds are noted off the southern Colombia offshores in addition to Ecuador and the Galapagos Islands. Meanwhile, cross- equatorial long- period south to southwest swell continues to propagate through the forecast waters producing wave heights of 5-7 ft. Slighter higher wave heights of 6-8 ft are just beyond the forecast waters. Strong thunderstorms are moving across the offshore waters of Costa Rica, Nicaragua and El Salvador. For the forecast, gentle to moderate winds and moderate seas will continue through the forecast period. Cross-equatorial long-period south to southwest swell will continue into mid-week, increasing across the offshore waters of Ecuador and the Galapagos Islands by Mon night and into Tue. Seas will slowly subside later in the week. A very moist and unstable atmospheric environment will maintain active weather across most of the offshore waters through the period. REMAINDER OF THE AREA... A surface trough is just west of the area along 141W from 20N to 27N. No convection is occurring with this feature. Relatively weak high pressure is present over the area north of the monsoon trough and west of 125W. The related rather light gradient is allowing for gentle to moderate trade winds over the waters north of the monsoon trough and west of 110W where wave heights are generally 5-7 ft ft. Moderate to fresh southerly winds are south of the monsoon trough along with seas of 7-9 ft due to a long-period southeast to south swell west of 103W, and long-period south to southwest swell west of 98W. An area of 8 ft seas was noted by an altimeter pass near 14N130W. For the forecast, little change in marine conditions are expected over the next couple of days as the remnant low of Kay over the northeast part of the area gradually weakens to a trough west Baja California Norte. A weak high pressure center will be over the northwest corner of the area near 30N140W. Moderate to fresh southwest winds and associated seas will continue south of the monsoon trough. The long-period southerly swell continue to longer across most of the southern waters into at least mid- week. The area of 8 ft seas near 14N130W will subside by Tue morning. $$ AReinhart