000 AXPZ20 KNHC 301011 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Sep 30 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 FEATURES... Tropical Depression Narda is centered near 21.5N 106.4W at 0900 UTC moving NW at 15 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. The center of Narda has emerged over the Pacific coastal waters of Mexico between Puerto Vallarta and Las Tres Marias, and is expected to continue NW this morning, passing just E of Las Tres Marias. A large line of strong thunderstorms has moved westward from the Sierra Madre Occidentales overnight and into the Gulf of California, and has consolidated into a large cluster of strong thunderstorms near the center of Narda, extending within 180 nm NW and 120 nm SE of the center. Narda is expected to strengthen to a minimal tropical storm by this afternoon and continue NW into the Gulf of California near or just offshore the coast of northwestern mainland Mexico through Tuesday. Narda is forecast to produce total rain accumulations of 5 to 10 inches along the southwestern coast of Mexico from Guerrero to Nayarit, and 1 to 4 inches over Baja California Sur through Monday night. Isolated maximum amounts of 15 inches are possible from Oaxaca to Nayarit. This rainfall will cause life- threatening flash floods and mudslides, especially in mountainous terrain. SW swells generated by Narda continue to affect portions of the coast of southwestern Mexico, from Tehuantepec to Cabo Corrientes, and will slowly diminish from east to west during the next 48 hours. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from near 09N74W to 08N85W to 14N91W, t hen, resumes W of tropical cyclone Narda from 14N108W to 15N128W to beyond 12N140W. Scattered moderate isolated strong convection is noted from 12N to 16N between 125W and 132W, and from 08N to 13N W of 132W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for information about Tropical Depression Narda. Overnight scatterometer data showed a broad area of strong SW winds continuing well south of Narda over the southern Mexico offshore waters, extending from near 11N119W to the coastal waters of Acapulco. Seas across this area are running 9 to 12 ft, and generating very high surf across the coasts. Please refer to statements issued by the Meteorological Service of Mexico for more information. Elsewhere, a ridge is building into the offshore waters of Baja California. This will bring fresh to locally strong NW winds near the coast of Baja California north of Cabo San Lazaro. Associated seas will build to 6 to 8 ft within the freshening flow, then subside by mid week as offshore winds are expected to diminish. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Generally moderate W to NW winds prevail north of Costa Rica to Tehuantepec, while moderate SW to W winds are noted south of Panama and off the coast of Colombia. Seas of 8 ft in long period SW swell persist across the waters off Guatemala, El Salvador, and Nicaragua with seas in the 5 to 7 ft range elsewhere across the region. Seas will subside below 8 ft by Mon night. Fresh to locally strong SW monsoon flow will resume on Tue between Central America and the Galapagos Islands, with seas building to 8 to 9 ft offshore of Costa Rica and Panama. REMAINDER OF THE AREA... High pressure located well NW of the forecast area is building into the northern waters in the wake of a weakening cold front. Overnight scatterometer data showed moderate to fresh NE winds north of 24N and west of 125W, with corresponding altimeter data indicating seas were 7 to 8 ft in this region. Seas will remain 8 ft through tonight as a northerly surge pushes southward, then subside early on Monday as wind speeds gradually diminish. Elsewhere, 1010 mb low pressure analyzed near 13.5N134W along the monsoon trough is supporting fresh to locally strong SW winds and 8 to 9 ft seas within 150 nm across the SE semicircle. Some slight strengthening is possible while the system drifts slowly east to northeastward. Additional low pressure development is expected along the monsoon trough west of 130W early next week, which will likely maintain fresh SW winds and 8 ft seas over the far SW portion of the forecast waters. $$ Stripling