860 AXPZ20 KNHC 182144 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Aug 18 2024 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Tropical Depression Seven-E was upgraded to Tropical Storm Gilma at 18/2100 UTC. At this time, it is centered near 14.7N 112.3W at 18/2100 UTC, moving west at 10 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous moderate to scattered strong convection is noted within about 180 nm W semicircle of low center. On the forecast track, slightly slower westward to west-northwestward motion is expected during the next few days. Gilma is forecast to remain well away from land throughout the week. Slow strengthening is expected during the next few days. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Gilma NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 10N90W to near 11N102W, then continues W of T.S. Gilma from 13N118W to 1011 mb low pressure near 14N123W to 1009 low pressure near 10.5N137.5W to beyond 11N140W. Aside from the convection associated with T.S. Gilma and the low pressure systems, scattered moderate to isolated strong convection can be found from 07N to 14N between 82W and 106W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Tropical Depression Seven-E developed in the morning south of Baja California, and it was upgraded to Tropical Storm Gilma at 18/2100 UTC. Please see the Special Features section for more details. A ridge continues to dominate the forecast waters off Baja California supporting gentle to moderate NW winds. Seas are 4 to 6 ft with some locally 7 ft seas near Isla Guadalupe. In the Gulf of California, gentle to moderate SE winds and 1 to 3 ft seas prevail. Moderate to locally fresh gap winds are in the Gulf of Tehuantepec with seas of 4 to 6 ft. Winds and seas associated with Gilma are brushing the outer offshore waters of Colima and Jalisco. Elsewhere across the Mexican offshore waters, mostly light winds prevail with seas of 3 to 5 ft in long period SW swell. For the forecast, a ridge will remain in place across the offshore waters of Baja California through the week producing gentle to moderate NW to N winds and moderate seas. Fresh winds will pulse nightly in the Gulf of Tehuantepec. Tropical Storm Gilma is forecast to move westward passing S of the Clarion Island on Mon. Another area of low pressure could form well to the south of the southwestern coast of Mexico around the middle of the week. Environmental conditions appear generally conducive for some slow development of this system thereafter as it moves slowly west-northwestward into the central portion of the East Pacific basin. There is a low chance of tropical cyclone formation of this system over the next 48 hours and within the next 7 days. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Mainly moderate NE winds are in the Gulf of Papagayo. Elsewhere, gentle to moderate S to SW winds are S of the monsoon trough, increasing to moderate to fresh speeds S of 05N based on scatterometer data. Light to gentle winds prevail N of it. Seas are generally 4 to 6 ft in long period SW swell. Higher winds and seas are near the convective activity associated with the monsoon trough. For the forecast, gentle to moderate S to SW winds will prevail south of the monsoon trough into mid-week while light to gentle winds are expected N of it. Seas will be in the 4 to 6 ft range. Fresh winds will pulse nightly in the Gulf of Papagayo beginning Tue night. ...REMAINDER OF THE AREA... Tropical Depression Seven-E was upgraded to Tropical Storm Gilma at 18/2100 UTC. Please see the Special Features section for more details. High pressure dominates the waters N of the monsoon trough producing a gentle to moderate anticyclonic flow, except across the NW waters and near the center where light and variable winds are noted. S of the monsoon trough areas of fresh to strong SW winds are noted, particularly SE and S of T.S. Gilma where seas are in the 8 to 11 ft range based on altimeter data. Elsewhere, seas average 5 to 7 ft. A 1010 mb low pressure along the monsoon trough located near 13N130W is producing fresh to locally strong winds and seas of 8 to 9 ft within about 120 nm NW quadrant of the low center. Another two low pressure systems are analyzed along the monsoon trough, one is near 14N124W 1010 mb, and the second one is located near 10.5N137.5W. The latter is the invest area EP90. For the forecast, Gilma will move to 15.1N 114.0W Mon morning, 15.6N 116.1W Mon afternoon, 15.9N 118.1W Tue morning, 16.2N 119.9W Tue afternoon, 16.6N 121.3W Wed morning, and 16.9N 122.5W Wed afternoon. Gilma will strengthen to a hurricane near 17.7N 125.0W Thu afternoon. Disorganized showers and thunderstorms continue in association with a broad trough of low pressure located well west-southwest of the southern tip of the Baja California peninsula. This system is forecast to interact with another disturbance to its west-southwest over the next few days, which could limit additional development if this system does not become the dominant disturbance. Regardless, a tropical depression could still form during the middle part of the week while the system moves generally west- northwestward before it possibly merges with the disturbance currently located further west. There is a low chance of tropical cyclone formation of this system over the next 48 hours and a medium chance of formation within the next 7 days. Another area of low pressure located well southeast of the Hawaiian Islands is producing some disorganized showers and thunderstorms on its western side. This disturbance is forecast to interact with the disturbance located to its east. If this system becomes the dominant disturbance, some gradual development is possible, and a tropical depression could form by the middle part of the week while it initially moves slowly over the western portion of the East Pacific. A faster west-northwestward motion into the Central Pacific basin is likely by the latter portion of the week. There is a low chance of tropical cyclone formation of this system over the next 48 hours and a medium chance of formation within the next 7 days. Please, refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details about all these systems with the potential of tropical cyclone development. $$ GR