000 AXPZ20 KNHC 190915 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0900 UTC Fri Jul 19 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. ...TROPICAL WAVES... A tropical wave with axis near 97W is moving west around 10-15 kt. Numerous showers and thunderstorms are ongoing along the northern portion of the tropical wave, likely influenced by a combination of overnight drainage flow and the tropical wave. A tropical wave with axis near 108W is moving west around 10-15 kt. Numerous showers are observed east of the tropical wave near the intertropical convergence zone, from 08N to 11N between 100W and 105W. Environmental conditions could become a little more more conducive for gradual development, and a tropical depression could form early next week before the system reaches cooler waters. Please see the latest eastern North Pacific Tropical Weather Outlook ABPZ20/KNHC TWOEP for more information. A tropical wave with axis near 130W is moving west around 10-15 kt. A 1008 mb surface low is analyzed along the wave axis near 12N130W. Scattered moderate convection is noted from 07N-10N between 120W-132W. An earlier scatterometer pass indicated the low pressure was poorly defined at the surface. This system has not become any better organized in the past couple of days, and the chances for tropical cyclone formation appears to be diminishing. Please see the latest eastern North Pacific Tropical Weather Outlook ABPZ20/KNHC TWOEP for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 07N85W to 09N92W. Segments of the ITCZ extend from 10N97W to 11N105W, from 11N110W to 07N115W to 08N125W, and from 10N135W to beyond 09N140W. Aside from the convection related to the tropical waves described above, scattered showers are noted within 90 nm north of the ITCZ west of 135W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak ridging north of 20N is supporting only gentle to moderate NW winds off the coast of Baja California. The resident trough over the peninsula is supporting gentle southerly flow across the Gulf of California. A few overnight showers are noted along the eastern shore of the southern Gulf of California between Mazatlan and Los Mochis. A lower to mid level trough is expected to emerge off north central Mexico and drift across the region Fri and Sat, allowing a slight increase in winds and likely a few more showers, before gradually returning to a more benign pattern by early next week. Farther south, the weak tropical wave moving across the Gulf of Tehuantepec is supporting showers and thunderstorms near the coast, as well as moderate to fresh gap winds. Ridging in the wake of the tropical wave and across the Gulf of Mexico will support fresh to strong gap wind pulses into the Gulf of Tehuantepec at least through late Sat, then diminishing as the high pressure weakens over the Gulf of Mexico. Looking ahead, various global models indicate some development along the tropical wave currently south of Baja California. If anything does develop, it may bring increased winds and seas to the Revillagigedo Islands by early next week, although there remains much uncertainty at this point regarding development, much less track and intensity. 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, as noted in a recent scatterometer satellite pass. These winds will persist through the weekend and into early next week, with associated seas peaking to 8 ft each morning. Winds in this region should remain gentle to moderate for the next several days. Seas to 8 ft in southerly swell will persist south of the Galapagos Islands through the weekend. REMAINDER OF THE AREA... Moderate to fresh trade winds persist south of 20N west of 135W, between weak ridging north of 20N and lower pressure along the intertropical convergence zone. Low level convergence of the enhanced trade winds is supporting scattered showers and thunderstorms along the ITCZ west of 135W as well. A more recent altimeter satellite pass confirmed 8 to 9 ft seas from 10N to 20N west of 135W, likely in a broad mix of swell, but mainly due to trade wind flow. Weak low pressure will persist into early next week, supporting seas to 8 ft generally from 15N to 20N west of 135W. Farther east, fresh winds were noted near the tropical wave along 108W, helping support the areas of convection along the ITCZ east of the wave axis. A surge of SW monsoon flow is anticipated in the wake of the tropical wave by Sun, possibly allowing further development between 110W and 120W into early next week. Please see the Tropical Waves section above for more information about the potential for tropical cyclone development over the next several days. $$ Christensen