000 AXPZ20 KNHC 100227 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Oct 10 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 0000 UTC surface analysis and satellite imagery through 0130 UTC. ...SPECIAL FEATURES... Gulf of California Gale Warning: A very tight pressure gradient will develop across the U.S. Great Basin region tonight through the end of the week. The probabilities for minimal gale force winds in the northern Gulf of California continue to trend upward, while a local research tool also shows a high chance for these conditions. Northerly winds in the northern Gulf of California will first increase to fresh to strong by Thu morning, and are forecast to reach minimal gale force Thu night into Fri before gradually diminishing. Seas will also build to 7-9 ft in the northern Gulf as a result of these winds. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... A tropical wave is W of the Pacific coast of Colombia near the Gulf of Panama along 78W/79W, moving W at 10-15 kt. Scattered moderate and isolated strong convection was noted E of the tropical wave axis to across western Colombia. A tropical wave is N of 04N to the NW Caribbean Sea along 86W, moving W at 10-15 kt. Scattered moderate and isolated strong convection was noted N of 11N between 86W and 91W, including across portions of western Nicaragua, Honduras, and El Salvador. A tropical wave is from 04N to 17N with an axis along 129W/130W, moving W at 5-10 kt. Limited associated convection was noted. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of western Costa Rica near 10N86W to low pressure near 12N105W to 10N120W to 09N130W to 09N140W. Scattered moderate and isolated strong convection was noted from 08N to 10N between 92W and 97W, N of 13N between 90W and 94W including along the coasts of Guatemala and far SE Mexico, and also from 07N to 10N between 120W and 128W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about the developing Gulf of California Gale Warning. Weak and broad 1011 mb low pressure is currently near 12N105W with a large area of deep convection nearby. Scattered moderate and isolated strong convection was noted within 17N106W to 14N97W to 08N108W to 10N116W to 17N106W. This low may gradually develop as it shifts WNW through the remainder of the week into the weekend, possibly bringing increasing winds and seas to the vicinity of the Revillagigedo Islands by this weekend. Gulf of Tehunatepec: Weak ridging in the eastern Gulf of Mexico is still supporting fresh to strong northerly winds along with 7-8 ft seas. These winds and seas will diminish and subside in the next few hours as the pressure gradient relaxes. Looking ahead, strong high pressure will build behind a cold front over the western Gulf of Mexico this weekend, supporting possible gale force northerly winds in the Gulf of Tehuantepec by Sat night. Elsewhere, a ridge will dominate the offshore forecast waters W of Baja California, supporting mainly gentle to moderate NW-N winds. A set of fresh NW swell behind a dissipated cold front will propagate into the offshore waters off Baja California Norte Thu, decaying by early Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will linger between 10N-12N for the next few days, with mainly moderate to fresh southerly flow S of it, and light to gentle variable winds N of it. Seas will be 4 to 7 ft, mainly in long period southerly swell. Winds may locally increase to fresh to strong W of Colombia to S of Costa Rica this weekend. These winds along with long period southerly swell may build seas to 6-8 ft. REMAINDER OF THE AREA... A surface ridge dominates the waters N of 20N W of 120W. The pressure gradient between this ridge and lower pressures in the vicinity of the monsoon trough is supporting mainly moderate to locally fresh trade winds. Northerly swell will propagate into the waters N of 26N between 120W and 135W Thu through Fri, with seas building to 8-10 ft. A decaying frontal boundary may drift into the northern waters this weekend with little impact. As mentioned in the Mexico offshore waters section above, weak and broad low pressure currently near 12N105W may gradually develop as it shifts WNW through the remainder of the week into the weekend, possibly bringing increasing winds and seas to the vicinity of the Revillagigedo Islands by this weekend. $$ Lewitsky