000 AXPZ20 KNHC 180338 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Jul 18 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 0300 UTC. ...TROPICAL WAVE... A tropical wave is near 87W from the Gulf of Honduras southward across Honduras/western Nicaragua into the East Pacific, and moving west around 20 kt. Scattered showers and isolated thunderstorms are evident 03N to 10N between the Nicaragua/Costa Rica coast and 87W. Another tropical wave is near 105W from Jalisco State in Mexico southward, and moving west at 15 to 20 kt. Scattered moderate convection is noted from 05N to 15N between 100W and 113W, and also near the coast of Jalisco. A third tropical wave is near 122W from 21N southward, and moving west at 10 to 15 kt. Widely scattered moderate convection is observed from 05N to 10N between 115W and 122W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A monsoon trough extends westward from central Costa Rica through 09N100W to 09N115W. Scattered moderate convection is seen from 05N to 11N between 92W and 100W, and from 05N to 10N between 110W and 115W. An ITCZ continues from 09N115W to 09N120W, then resumes southwestward from 09N122W across 06N130W to beyond 04N140W. Numerous moderate to isolated strong convection is seen up to 250 nm along either side of the second ITCZ segment. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to strong northerly gap winds are noted in the Gulf of Tehuantepec. This is due to a tighter pressure gradient from high pressure extending over the Gulf of Mexico. Seas are likely near 7 ft downstream in the Gulf of Tehuantepec mixing with longer period southerly swell moving into the region. Farther north, weak ridging persists over most of the area. This is leading to gentle to moderate winds and slight to moderate seas. Scattered thunderstorms are noted south of Michoacan associated with the tropical wave along 103W. Some of these storms are producing gusty winds and seas up to 7 ft. For the forecast, the fresh to strong northerly winds are forecast to persist in the Tehuantepec region through Thu week with seas building to 8 ft. Farther north, a weak ridge will continue to dominate the Baja California offshore waters through most of the week. This will maintain gentle to moderate NW winds and slight to moderate seas. The Gulf of California can expect seas of 3 ft or less. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong NE to E winds prevail across the Papagayo region and downwind to about 95W. Seas to 7 ft are within these winds. Light to gentle winds and seas of 3 to 5 ft are noted over the remainder of the offshore waters north of 03N. Gentle to moderate southerly winds are observed south of 03N where seas are 3 to 5 ft. Numerous thunderstorms are noted across the Costa Rica and Panama offshore waters associated with a tropical wave along 83W. Scattered thunderstorms are also noted in the Colombia offshore waters. For the forecast, the fresh to strong NE to E winds are forecast to pulse in the Papagayo region through Thu night with seas building near 8 ft. Light to gentle winds will dominate most of the offshore forecast waters. Gentle to moderate southerly winds can be expected between Ecuador and the Galapagos Islands, and moderate to locally fresh NE to E winds across the offshore waters of Guatemala and El Salvador. Outside of the Papagayo region, seas of 4 to 6 ft in mostly S to SW swell are expected. However, seas generating in the Papagayo area will spread across the offshore waters of Guatemala and El Salvador building seas to 5 to 7 ft. ...REMAINDER OF THE AREA... T.S. Calvin has moved west of the area. Please see the latest forecast/advisory and Public Advisory from the Central Pacific Hurricane Center at www.hurricanes.gov for more details. The latest scatterometer pass shows strong winds from the influences of T.S. Calvin extend over a small portion of the western forecast waters, from 17N to 20N and W of 139W. Seas are 8 to 12 ft from 14N to 23N and W of 137W. These conditions will improve quickly with the strong winds ending in a few hours and seas dropping below 8 ft by Tue morning. Aside from Calvin, a ridge prevails across the north waters anchored by a 1028 mb high pressure center located north of the area near 37N138W. Gentle to moderate NE winds are noted N of the ITCZ/monsoon trough and W of 115W due to the influence of the ridge. Seas range 4 to 7 ft. Winds are moderate to locally fresh S of the ITCZ/monsoon trough with seas 4 to 6 ft. Wind and seas could be higher near the convective activity along the ITCZ/monsoon trough. For the forecast, fresh to strong winds and moderate to rough seas will develop along a tropical wave as it moves westward from 10N to 15N between 105W and 120W. Northerly swell could impact the northern waters later today through Tue evening, bringing seas near 8 ft N of 28N between 127W and 131W. Otherwise, moderate to locally fresh winds with moderate seas can be expected N and S of the ITCZ/monsoon trough through the rest of the week. $$ Forecaster Chan