367 AXPZ20 KNHC 210929 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 929 UTC Sun Jul 21 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURE... Gale warning: Recent satellite imagery indicates that a broad and elongated low pressure area located near 12N115W continues to become better organized. Environmental conditions are expected to be conducive for additional development of this system, and a tropical storm is likely to form within the next day or two. Scattered moderate to isolated strong convection is ongoing within 180 nm in the northern semicircle of the low pressure. Winds are expected to increase to minimal gale force by late tonight as the system becomes better organized, and there is a high chance of tropical storm development through late Mon. This disturbance is forecast to move generally northwestward at around 10 mph away from the coast of Mexico, although winds to gale force may pass within 120 nm west of Clarion Island by early Tue, with seas to 10 ft reaching the island. Please see the latest eastern North Pacific Tropical Weather Outlook at hurricanes.gov for more information. ...TROPICAL WAVES... A tropical wave with axis near 94W is moving west around 15-20 kt. Scattered moderate convection is noted along the monsoon trough near the wave axis, from 06N to 08N between 90W and 97W. A tropical wave with axis near 109W is moving west around 10 kt. Scattered convection is noted north of the tropical wave from 18N to 20N between 105W and 110W. A tropical wave with axis along 119W is moving west at 10 kt, related to the low pressure near 12N115W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07N77W to 09N100W to 14N110W to the low pressure near 12N115W to 06N125W. The ITCZ extends from 06N125W to 05N140W. Beyond than what is described in the Special Feature and Tropical Wave sections above, numerous moderate to scattered strong convection is noted from 03N to 07N east of 82W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak ridging is supporting gentle to moderate NW winds off Baja California, and light to gentle southerly flow over the Gulf of California. The main forecast issue into mid week will be the development and track of the developing low pressure area currently near 12N115W. The low pressure is forecast to make its closest point of approach west of Clarion Island by early Tue as a gale center or tropical storm. Seas to 10 ft are expected to impact the Clarion area late Mon into Tue as the low moves past. In addition, the track of the low will allow regional high pressure to build east of the Revillagigedo Islands, resulting in a slight enhancement of NW winds off the coasts of Colima and Jalisco south of Cabo Corrientes late Mon into Tue. Farther south, a recent scatterometer pass showed fresh gap winds over the Gulf of Tehuantepec. This will diminish through the morning, but brief pulses to 20 kt are possible in this region through the remainder of the period mainly overnight. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient across Central America is maintaining fresh to strong NE to E winds near and downstream of the Gulf of Papagayo. These winds will continue pulsing through early this week with the strongest winds occurring during the overnight and early morning hours. Seas will peak near 8 ft each morning downstream of the Gulf. Elsewhere, moderate winds south of the monsoon trough will briefly strengthen to fresh speeds Sun night and Mon, with seas building to 8 ft off the coast of Panama and Colombia. Looking ahead, seas will build to 8 ft or greater over the southern waters by mid week in long period S to SW swell. REMAINDER OF THE AREA... A Kelvin wave moving across the central Pacific is supporting weak surface low pressure near 18N134W. This system is likely producing a small area of fresh winds with seas to 9 ft based on the latest model guidance. This low will rapidly weaken through tonight as it drifts northward while the Kelvin wave continues propagating eastward. Elsewhere, moderate trade winds are roughly north of 20N and west of 135W between weak ridging north of the area and the aforementioned low. $$ Christensen