000 AXPZ20 KNHC 160155 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue May 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 0000 UTC surface analysis and satellite imagery through 0050 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from Colombia near 10N75W to 05N94W to 06N100W. The ITCZ extends from 06N100W to 07N130W to beyond 03N140W. Numerous moderate scattered strong convection is noted from 02S to 10N between 77W and 87W. Scattered moderate isolated strong convection is noted from 00N to 07N between 92W and 102W, from 07N to 10N between 100W and 110W, and from 03N to 08N between 121W and 135W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh N winds are developing in the immediate Gulf of Tehuantepec due to a locally tight pressure gradient combined with nocturnal drainage flow. Elsewhere, high pressure ridging extends from NW to SE across the offshore waters of Mexico with gentle to moderate winds. Seas of 5-7 ft in S-SW dominate the open waters, mixed with NW swell offshore Baja California. In the Gulf of California, light to gentle SE-S winds and seas of 1-3 ft or less prevail, except 3-5 ft near the entrance. Hazy skies persist across the near and offshore waters from Las Tres Marias to Tehuantepec due to lingering smoke from ongoing agricultural fires with possible reduction in visibility to 5 nm. For the forecast, N winds will increase to fresh to strong in the Gulf of Tehuantepec tonight through Tue morning, then again Fri night/Sat morning and Sat night/Sun morning with seas of 6-8 ft. Winds from near Cabo San Lucas into the southern Gulf of California may increase to fresh to strong Wed night as a weak area of low pressure develops. Fresh to strong winds may pulse near Cabo San Lucas again Sat night and Sun night. Otherwise and elsewhere, little change in winds is forecast through Sat. Large cross equatorial southerly swell will arrive offshore Mexico late tonight/early Tue through Wed building seas to around 8 ft, with another yet weaker pulse of S swell arriving on Fri. Reduced visibilities in haze are possible in the S and SW Mexico offshore waters due to smoke produced by agricultural fires. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Numerous showers and thunderstorms are occurring across most of Colombia extending westward to across portions of Panama, Costa Rica, and offshore from 02S to 10N. Model guidance continues to indicate the potential for higher winds and seas with this convection. Gentle to moderate winds are elsewhere with 5-7 ft seas in S-SW swell offshore Ecuador, except building to 9 ft S of the Galapagos Islands, and 4-7 ft elsewhere. Hazy skies persist from the Papagayo region to Tehuantepec due to lingering smoke from ongoing agricultural fires, with visibilities likely 5 nm offshore from the Gulf of Fonseca to El Salvador. For the forecast, strong thunderstorm activity is expected to persist across the waters from Costa Rica and Panama southward through at least tonight with the potential for higher winds and seas. NE to E gap winds will pulse to fresh to strong across the Papagayo region during the overnight and early morning hours beginning Thu night. Building S-SW swell from offshore Ecuador to the Galapagos Islands will reach the nearshore waters of Central America early on Tue with peak seas of 7-8 ft. New SW swell should reach the Galapagos waters early Thu, with seas building to 7-9 ft yet again across the offshore waters from Ecuador to the Galapagos Islands Thu night through Sat. Reduced visibilities in haze are expected from the Guatemala to the Costa Rica offshore waters due to smoke produced by ongoing agricultural fires. ...REMAINDER OF THE AREA... A slow moving cold front extends from 30N135W to 24N140W. Moderate to fresh S-SW winds ahead of the front are N of 27N within about 60-120 nm of the front. NW swell of 7-8 ft covers the waters N of 20N. Weak ridging prevails ahead of the front and N of the ITCZ with mainly gentle to moderate winds, beginning to increase to moderate to fresh, and 7-9 ft seas in mixed S and NW swell per earlier altimeter passes. A set of S-SW swell with seas of 7-10 ft is spreading across the remainder of the open waters this evening. For the forecast, the front will stall tonight, with associated seas subsiding to less than 8 ft by early Tue. Another weak front or trough will move into the NW waters by mid-week, with another pulse of NW swell building seas to 8-10 ft Wed before decaying. Winds will increase slightly across the trade wind zone tonight and Tue, and again Fri night into the upcoming weekend, but otherwise, little change in winds is forecast through the next several days. Meanwhile, the S-SW swell will continue to propagate northward through the early part of the week, with combined seas of 7-10 ft dominating almost the entire open waters by tonight/early Tue. The seas will then slowly decline through Wed. A new set of S-SW swell of 7-10 ft will reach the Equator Wed night, extending to near 10N Fri. $$ Lewitsky