000 AXPZ20 KNHC 182204 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Apr 18 2019 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehunatepec Gale Warning: Gentle to moderate south to southwest winds across the Gulf will become moderate to fresh north winds early Fri, before abruptly increasing to minimal gal- force speeds Fri morning around 1200 UTC. Winds will further increase to a strong gale Fri afternoon through early Sat as a very tight pressure gradient sets up over southeastern Mexico. Waveheights will build to the range of 11-18 ft with these winds Fri night. The pressure gradient will begin to slacken on Sat as the high pressure center over eastern Mexico shifts eastward and weakens. Strong winds of 20-25 kt are forecast to reach as far south as 09N and between 93W and 100W Sat morning, with waveheights of 10-14 ft in mixed NE and SW swell. These winds will diminish to fresh winds Sun morning, with seas lowering to less than 8 ft subsequently. Please refer to the Pacific High Seas Forecast under the AWIPS header MIAHSFEP2 and under the WMO header FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 08N84W to 06N93W to 03N101W. The ITCZ extends from 05N127W to 02N140W. Scattered moderate to strong convection is from 03N to 10N between 81W and 102W. Scattered moderate convection is from 01S to 3.5S between 101W and 125W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure of 1026 mb is analyzed north of the area near 35N133W, with a ridge extending southeastward to just NW of the Revillagigedo Islands. The pressure gradient associated with this high supports mainly moderate N to NW winds across the offshore waters of Baja California. Waveheights with these winds are in the range of 5-7 ft attributed to NW swell. Little change in these conditions is expected through Sun morning. On Sun morning, low pressure deepening over the state of Nevada will increase the pressure gradient between the ridge and the area of low pressure, thus resulting in moderate to fresh NW winds mainly N of Cabo San Lazaro and moderate winds elsewhere off the coast of Baja. A new pulse of NW swell will begin to propagate through the far northeastern waters early on Sun, bringing seas of 7-9 ft there. This swell will gradually decay through Mon. Gulf of California: Fresh to strong NW winds will resume this evening S of 28N, with seas up to 7 ft. These winds will diminish to mainly fresh winds early on Fri and to gentle to moderate winds Fri afternoon. Gulf of Tehuantepec: Please read the SPECIAL FEATURES section for details about a gale warning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to fresh NE to E winds will pulse at night, increasing to fresh to strong Sat evening as the pressure gradient tightens from southern Mexico to Costa Rica. Strong winds downstream will reach 09N and 91W on Sun morning with seas to 8 ft. Fresh to strong winds will continue to pulse every night through Tue, however seas are expected to be below 8 ft. Gulf of Panama: Mainly variable light to NE moderate winds are expected through early next week. Light to moderate wind speeds will prevail elsewhere across the waters west of Ecuador through Mon night. The sea heights will remain in the range from 6 feet to 7 feet, in S to SW swell through midweek. REMAINDER OF THE AREA... A high pressure ridge extends into the area N of 14N W of 113W. A trough extends from 02N128W to 09N128W. The pressure gradient between the ridge and lower pressure in the subtropics and tropics is resulting in fresh northeast to east trades from 05N to 12N between 123W and 130W, and from 08N to 11N W of 136W with seas to 9 ft. These winds are forecast to increase to strong speeds beginning late tonight as the ridge builds some southward tightening the gradient. These winds will change little in speeds through Sat as the gradient remains intact. $$ Ramos