000 AXPZ20 KNHC 190903 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 903 UTC Tue May 19 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N79W to 12N105W to a 1010 mb low pressure center near 11N110W to a 1010 mb low pressure center near 08N125W. The intertropical convergence zone is located from 08N125W to beyond 07N140W. Numerous strong convection is observed within 60 nm of the coast of Nicaragua, and off Chiapas. Scattered moderate convection is noted from 08N to 12N between 107W and 111W, and from 07N to 10N between 114W and 122W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak cold front reaching the northern coast of Baja California Norte and Guadalupe Island. The resulting tightening pressure gradient is forcing SW gap winds across a low point in the terrain over Baja California Norte near 30N. Fresh to strong SW winds may pulse across the northern portion of the Gulf of California through early morning as a result. The limited fetch and duration will keep seas less 5 ft. These winds will shift NW and diminish through late morning as the front moves east and dissipates. High pressure building in the wake of the front will support fresh to strong winds and seas to 9 ft north of Cabo San Lazaro Tue through Wed night. Farther south, local drainage flow along with a modest increase in the high pressure over the Gulf of Mexico will support brief pulses of fresh northerly gap winds into the Gulf of Tehuantepec this morning and again Tue night. Elsewhere, gentle to moderate mainly westerly breezes persist over Mexican offshore waters, with seas 4 to 6 ft in SW swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... North of the monsoon trough, generally light to gentle winds prevail, whereas south of the trough, moderate south and southwest winds are evidenced by recent ship observations and earlier scatterometer data. Seas across the area are 4 to 6 ft. Rich deep layer moisture along with favorable winds aloft is enhancing clusters of thunderstorms along the coast of northern Central America. This will diminish somewhat later this morning, but expect showers and thunderstorms farther offshore later today. Looking ahead, gentle to moderate winds will persist much of the week. The monsoon trough will likely remain active, leading to more significant showers and thunderstorms for the waters offshore Colombia, Panama, and Costa Rica. REMAINDER OF THE AREA... A weakening cold front extends from northern Baja California Norte to 24N130W. Recent altimeter satellite passes confirm large NW swell accompanies the front, with wave heights to 9 ft. Farther south, scattered showers and thunderstorms persist near a pair of low pressure areas persist along the monsoon trough, near 109W and 125W. The advancing cold front has interrupted the subtropical ridge, resulting in modest trade wind flow deeper into the tropics, although winds to 20 kt are likely near these low pressure centers. Altimeter data also shows a large area of 7 to 8 ft seas persisting from 09N to 12N between 105W and 112W, near the easternmost low pressure. This is likely due to lingering long period SW swell. Neither low is expected strengthen in the next several days, and seas will gradually fall below 8 ft by mid week. $$ Christensen