National Hurricane Center's Tropical Weather Discussion

Eastern Pacific Ocean

376 AXPZ20 KNHC 160843 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0830 UTC Wed Oct 16 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 0830 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Seventeen-E is centered near 15.4N 94.9W at 16/0900 UTC moving NW at 11 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Seventeen-E is forecast to move inland over southern Mexico today, and dissipate Thu. This system is embedded within the larger circulation of a Central American Gyre. A large area of scattered convection associated with this system is noted over the forecast waters N of 08N between 88W and 103W. Heavy rainfall associated with this system is expected across portions of southern Mexico during the next day or two. These rains could cause flooding and mudslides, especially in mountainous areas. See latest NHC forecast/ advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 115W, from 04N to 18N, moving W at around 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N85W to 15N95.5W to 12.5N129W. Scattered moderate isolated strong convection was noted from 01N to 08N E of 80W. Scattered moderate isolated strong convection was noted from 10N to 13N between 106W and 123W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about the Central American Gyre and Potential Tropical Cyclone Seventeen-E. Elsewhere, a ridge will build through the week across the Baja California offshore waters producing mainly a moderate NW to N wind flow. A set of large NW swell will propagate into the Baja California Norte offshore waters by the end of the week with seas of 8-12 ft, spreading SE and reaching the Revillagigedo Islands by Sat night and continuing through Sun night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please read the Special Features section for more details about the Central American Gyre and Potential Tropical Cyclone Seventeen-E. REMAINDER OF THE AREA... A broad and weak ridge is across the waters N of the monsoon trough and W of 115W. Earlier scatterometer data shows gentle to moderate trades, along with seas of 4-7 ft as indicated by altimeter data. A weak 1009 mb low pressure area is embedded in the monsoon trough near 12.5N126W. Scattered moderate convection is noted from 08N to 16N between 123W and 128W. An area of fresh to locally strong winds and seas to 8 ft are within 90 nm E of the low center. This low is forecast to linger in the same general area through the week with similar winds and seas in the vicinity. The latest scatterometer pass indicates that the area of low pressure that was near 15N134W has opened up into a trough. The pressure gradient between the trough and the broad ridging to the N is supporting an area of moderate to fresh winds from 15N to 20N between 132W and 137W. Seas are in the 7 to 8 ft range over this area. An area of moderate to fresh winds and seas to 8 ft will remain N of the trough as it shifts westward. The trough will shift W of the area Thursday, with associated seas subsiding below 8 ft late Thu night. A cold front will approach near 30N140W tonight. The front will usher in a set of long period NW swell, with seas of 8 to 10 ft affecting the waters N of 28N W of 130W by Thu morning. This swell will continue to propagate SE-S through the end of the week, with seas of 8 ft or greater likely covering the waters N of 20N W of 110W, and from 10N to 20N W of 115W by Sat. The swell will slowly decay from NW to SE by the end of the upcoming weekend. $$ AL