000 AXPZ20 KNHC 092107 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Oct 9 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 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 upwards, 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, reaching minimal gale force Thu night into early 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 nearing the Pacific coast of Colombia along 77W, moving W at 10-15 kt. Scattered moderate and isolated strong convection was noted over the Pacific N of 03N to the E of 82W. A tropical wave is N of 04N to the NW Caribbean Sea along 84W/85W, moving W at 5-10 kt. Limited associated convection was noted over the Pacific, however, deep convection is inland over portions of Costa Rica and Nicaragua. A tropical wave is from 04N to 18N with an axis along 128W/129W, moving W around 10 kt. Limited associated convection was noted. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from western Costa Rica near 10.5N86W to low pressure near 12.5N100W to 14N108W to 10N120W to 09N127W to 09N140W. Scattered moderate convection was noted from 09N to 12N between 87W and 94W, and also from 08N to 10N between 130W and 132W. Scattered moderate and isolated strong convection was noted from 08N to 10N between 117W and 124W, and also from 13N to 16N between 118W and 124W. 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 low pressure is currently near 12.5N100W with a large area of deep convection nearby. Scattered moderate and isolated strong convection is within 20N105W to 15N97W to 10N99W to 08N110W to 20N105W. This low may gradually develop as it shifts WNW through the remainder of the week into the weekend, brining 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 late tonight 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 dissipating 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 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 12.5N100W may gradually develop as it shifts WNW through the remainder of the week into the weekend, brining increasing winds and seas to the vicinity of the Revillagigedo Islands by this weekend. $$ Lewitsky