417 AXPZ20 KNHC 150347 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Sep 15 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Tropical Storm Karina is centered near 19.1N 119.8W at 0300 UTC moving NW at 12 kt. Estimated minimum central pressure is 996 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Numerous moderate and isolated strong convection is noted within 300 nm in the SW semicircle and within 30 nm in the NE semicircle of Karina. Scattered moderate convection is noted from 14N to 16.5N between 119W and 122W. Karina is moving toward the northwest and this motion is expected to continue over the next couple of days. Upper level wind shear appears to have abated tonight and allowed for some minor strengthening this evening, and there is a small window of opportunity overnight for modest strengthening. Karina will reach cooler waters within 24 hours and a gradual weakening trend is then expected thereafter. Please read the latest NHC Public Advisory at: https://www.nhc.noaa.gov/text/MIATCPEP1.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP1.shtml for more details. ...TROPICAL WAVES... A tropical wave axis is along 98W N of 04N, moving W at around 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N73W to 08N81W to 13N98W to 12N103W, then resumes from W of Karina near 15N126W to low pressure near 14N134W 1010 mb to 10.5N140W. Scattered moderate isolated strong convection is noted from 07.5N to the coast as far north as 18N between 10N between 81W and 110W. Scattered moderate convection from 08N to 13.5N west of 126W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for more details on Tropical Storm Karina. South to southwest swell from Karina will continue to spread northward across the Mexican waters from near Cabo Corrientes to the Baja California offshore waters through Tue. Moderate northwesterly winds prevail over the Baja California waters north of Punta Eugenia, where seas are 4-6 ft. Elsewhere, light to gentle winds prevail along the coast of southern Mexico. Seas are 3 ft or less in the Gulf of California, and 4-7 ft in southerly swell elsewhere S of Punta Eugenia. Moderate northerly winds will prevail offshore N of 20N or so in the wake of Karina, with light to gentle winds elsewhere through the week. Seas will be mainly 4-7 ft in mixed swell across the waters in the wake of Karina, except 3 ft or less in the Gulf of California, occasionally 2-4 ft in the central and northern Gulf. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate S to SW winds persist south of the monsoon trough, which extends across the offshore waters roughly along 09N-11N. Elsewhere, gentle winds prevail north of the monsoon trough. Combined seas are in the 4-7 ft range in a mix of wind waves and S to SW swell. Gentle to moderate monsoonal flow will prevail over the waters generally S of 10N for the next several days. Combined seas may slightly increase in the waters E of 90W Tue night through Thu night as S to SW swell moves across the region. REMAINDER OF THE AREA... Please see the Special Features section above for more details on Tropical Storm Karina. Tropical storm conditions and seas of 10-18 ft will shift northwestward over the next few days as Karina moves farther away from the coast of Mexico. A cold front has moved just SE of 30N140W with moderate SW winds ahead of it as noted by afternoon scatterometer data. The front will manage to make a little bit more E-SE progress during the next couple of days before stalling out and dissipating. A weak 1018 mb high pressure is centered near 26N134W. South of the ridge, mainly moderate to locally fresh NE trades prevail across the waters north of the monsoon trough. Combined seas are generally 5-7 ft. Fresh to strong NE winds are found within 120-180 nm to the NW of low pressure near 14N134W, where seas are locally 8-9 ft. A broad area of fresh to locally strong monsoonal flow prevails south of the monsoon trough between 115W and 135W, with seas generally 7-9 ft in this region. Decaying, long-period S to SW swell lingers across the waters E of 120W, with 6-7 ft combined seas south of the equator. New southerly swell will move across the southern waters tonight to raise seas to around 8 ft along the equator through the middle part of the week. $$ Stripling