000 AXPZ20 KNHC 201557 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1529 UTC Thu Aug 20 2020 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1515 UTC. ...SPECIAL FEATURES... Hurricane Genevieve is centered near 23.3N 111.4W at 20/1500 UTC moving NW at 10 kt. Estimated minimum central pressure is 984 mb. Maximum sustained wind speed is 65 kt with gusts to 80 kt. Seas 12 ft or greater are within 150 nm of center with peak seas to 26 ft. Scattered moderate and isolated strong convection is within 270 nm in the NE semicircle. Scattered moderate convection is within 180 nm in the S quadrant. Genevieve is forecast to weaken to a tropical storm by this evening while it continues to pass offshore of Baja California, then weaken to a tropical depression by early Sat while moving away from Baja California. Please read the latest NHC Public Advisory at: https://www.nhc.noaa.gov/text/MIATCPEP2.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP2.shtml for more details. ...TROPICAL WAVES... A tropical wave axis is analyzed near 78W/79W from near the Ecuador/Colombia border N across the Gulf of Panama into the SW Caribbean Sea, moving W at 15-20 kt. Scattered moderate and isolated strong convection is noted from 05N to 10N between 78W and 88W. Heavy rainfall is likely along the coast of Central America through the weekend. A tropical wave axis is analyzed near 103W N of 05N to the coast of SW Mexico, moving W at 10 kt. Scattered moderate and isolated strong convection is noted from 08N to 16N between 99W and 105W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11N76W to 08N83W to 11N87W to low pressure near 10N94W to 11N99W, then resumes from 18N108W to low pressure near 15N124W to low pressure near 12N129W to 10N135W to 11N140W. Besides the convection described above, scattered moderate and isolated strong convection is noted from 06N to 12N between 90W and 98W, and from 12N to 17N between 110W and 118W. Scattered moderate convection is noted from 07N to 11N between 125W to 135W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details about Hurricane Genevieve. Peak seas are currently around 26 ft S-SW of the southern tip of Baja California Sur near 23N110.5W. Swell associated with Genevieve is producing 8-12 ft seas in the southern Gulf of California, per earlier altimeter data. Genevieve will continue producing dangerous, life-threatening marine conditions over the next few days as it crosses the Baja California offshore waters. Elsewhere, expect fresh to strong S to SE winds in the northern Gulf of California today and Fri with seas building to around 5-7 ft. Moderate northerly winds in the Gulf of Tehuantepec will diminish later today. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Earlier scatterometer data showed moderate to locally fresh SW winds south of the monsoon trough, which extends along 09N-10N this morning. Associated seas are 6-9 ft per earlier altimeter data well offshore of Nicaragua and Costa Rica. The monsoon trough will gradually lift northward over the next several days. This will result in freshening winds and building seas off the coast of Central America through the upcoming weekend and into early next week. Seas will build to 8-10 ft offshore of Central America by this weekend in association with the strongest winds, then continue building to 9-12 ft early next week as monsoonal flow continues strengthening. REMAINDER OF THE AREA... A modest pressure gradient between high pressure north of the area and the monsoon trough is supporting gentle to moderate trades N of 20N and W of 125W, as shown in earlier scatterometer data. Moderate to locally fresh SW winds persist south of the monsoon trough, with the strongest winds noted between 90W-100W and 110W-130W. Seas peak around 8 ft within these fresh trades. This monsoonal flow is expected to strengthen E of 115W this weekend into early next week, with seas building to 8-12 ft. Elsewhere, northerly wind waves combined with SE swell from Genevieve will produce combined seas of 8-10 ft over the northern waters between 120W and 130W later today and into the weekend. An area of low pressure is expected to form this weekend several hundred miles southwest of the southwestern coast of Mexico. Conditions appear favorable for some slow development of this system, and a tropical depression could form by the middle of next week while it moves little. This system has a medium chance of tropical cyclone formation during the next five days. $$ Lewitsky/Hagen