000 AXPZ20 KNHC 150913 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jun 15 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...TROPICAL WAVES... A tropical wave extends its axis along 81W from 14N in the southwest Caribbean through western Panama and into the east Pacific to 05N. The tropical wave is moving W at 10 kt. Scattered moderate to strong convection is noted from 03N to 11N between 77W and 87W, including offshore of Costa Rica and near the coast of Colombia. A tropical wave is along 92W from 04N to 12N, moving west at 10 kt. Scattered moderate convection is noted from 02N to 13N between 87W and 100W. A tropical wave is along 113W from 03N to 13N, moving west at 5 to 10 kt. See monsoon trough section below for convection. A tropical wave is analyzed along 126W from 06N to 14N, moving west at 5 kt. No significant convection is evident in the vicinity of the wave. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 12N99W to 1008 mb low pres near 10N110.5W to 07N119W to 09N128W to 08N131.5W. The ITCZ continues from 08N131.5W to 06N140W. Aside from the convection associated with the tropical waves, scattered moderate isolated strong convection is evident from 06N to 14N between 100W and 114W. Scattered moderate convection is noted from 05N to 08N between 118.5W and 123W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Recent ASCAT satellite wind data shows fresh NW winds occurring W of Baja California, mainly for areas south of El Rosario, due to the pressure gradient between high pressure well W of the area and low pressure centered south of Las Vegas, Nevada. Seas are 5 to 7 ft in this area. Fresh SW gap winds are likely occurring in the northern Gulf of California, aided by a surface trough over the Gulf, where seas are likely 3 to 4 ft. In the southern and central Gulf of California, winds are light to moderate with 1 to 3 ft seas, except 4-5 ft at the entrance to the Gulf. Light to gentle winds prevail elsewhere off Mexico, to the east of 108W, with seas generally 4 to 6 ft. Isolated to scattered thunderstorms are noted offshore from 14N to 16N between 93W and 100W. Smoke from agricultural fires over Mexico may be reducing visibility to around 5 nm in some areas near the coast from Guerrero eastward to the Guatemala border. For the forecast, a trough will deepen slightly over the lower Colorado River Valley and northern Gulf of California through Fri, while a weak ridge persists between Los Cabos and the Revillagigedo Islands. This pattern will support a continuation of fresh NW winds west of Baja California through late Fri, with fresh SW winds pulsing over the northern Gulf of California tonight. Gentle winds will persist elsewhere. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... ASCAT data from 15/0247 UTC indicates fresh to strong, with locally near gale force winds in the Papagayo region, strongest from 10N to 11N between 86W and 87W. That ASCAT pass also showed fresh to locally strong winds elsewhere within 60 nm of the coast from northern Costa Rica to eastern El Salvador, including the Gulf of Fonseca. Some of these winds occurred in isolated thunderstorm activity in the area. Winds in the Papagayo region have likely diminished to moderate to fresh since that time. Light to gentle and variable winds prevail elsewhere over the offshore waters of Central America and Colombia. To the south of 02N, gentle to moderate S winds are present, including the waters between Ecuador and the Galapagos Islands. Seas are 6 to 8 ft between Ecuador and the Galapagos Islands in S swell. Seas are 4-6 ft offshore Colombia, Panama and Costa Rica in S swell. Seas are 3-5 ft elsewhere. Significant thunderstorm activity is affecting portions of the waters offshore Costa Rica and Colombia. For the forecast, moderate to fresh winds will pulse in the Papagayo region and downwind to 89W, mainly at night, through Sat night, with moderate winds also possible off El Salvador. Elsewhere, mainly light to gentle variable winds will prevail across the Central America offshore waters. Gentle to moderate S winds will continue west of Ecuador. Southerly swell of 6 to 8 ft between Ecuador and the Galapagos Islands should gradually subside to 5 to 6 ft by Fri. ...REMAINDER OF THE AREA... Moderate to fresh NW to N winds are noted in recent ASCAT data on the west side of 1008 mb low pressure along the monsoon trough near 10N110.5W. Seas in this area are 6 to 8 ft. Farther south, southerly swell is still reaching 8 ft as far north as the equator. Farther north and west, a ridge extends from 1031 high pressure centered well north of the area southeastward across the subtropical waters to near 17N115W. The pressure gradient between the ridge and lower pressures associated with the monsoon trough/ITCZ is supporting a belt of fresh NE winds N of the ITCZ to 20N and west of 130W, where seas are 6 to 8 ft in mixed SE and N swell. Moderate winds are elsewhere from the ITCZ to 20N and west of 120W. The ridge is supporting moderate to fresh NE winds north of 25N and west of 130W, with 5 to 7 ft combined seas. Mainly gentle northerly winds are elsewhere north of the ITCZ/monsoon trough while gentle to locally moderate SE winds with seas 5 to 7 ft are south of these boundaries in southerly swell. For the forecast, the low pressure along the monsoon trough, mentioned above, may support fresh to locally strong winds, rough seas and thunderstorms within 90 nm of the center through the next couple of days before the low gradually weakens. There is a low chance of tropical cyclone development through 48 hours. See hurricanes.gov for more information. Elsewhere, fresh NE winds and building seas can be expected today, north of 25N and west of 130W between high pressure northwest of the area and a persistent trough extending southwestward off southern California. Expect the NE winds in this area to increase to fresh to strong for Fri night into Sat. Northerly swell of 8-10 ft will also affect these waters N of 25N and west of 125W Fri into Sun. Elsewhere, little change in the pattern or impacts is expected through the weekend, except for slightly higher trade wind flow north of 08N and west of 125W. $$ Hagen