000 AXPZ20 KNHC 300246 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2354 UTC Sun Sep 29 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 0230 UTC. ...SPECIAL FEATURES... Tropical Depression Narda is centered near 20.6N 105.2W at 30/0300 UTC moving NW at 18 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. On the forecast track, the center of Narda will emerge over the Pacific waters early Monday, and move near or across Las Marias Islands. Narda is then forecast to move over the Gulf of California near or just offshore the coast of northwestern mainland Mexico through Tuesday. Slow strengthening is forecast once the center moves back over the Pacific Ocean, and Narda is expected to become a tropical storm again Monday morning. 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. Swells generated by Narda are affecting portions of the coast of southwestern Mexico. These swells are expected to spread northward and will likely cause life-threatening surf and rip current conditions along the west coast of mainland Mexico, along the east coast of Baja California Sur, and in Las Marias Islands. 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 a 1007 mb low pressure located over northern Colombia near 09N74W to 08N85W to 14N91W. Then, 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. Scatterometer data revealed a broad area of strong SW winds well south of Narda over the southern Mexico offshore waters. The most recent altimeter pass showed seas of 9 to 12 ft within this enhanced SW wind flow, peaking S of Acapulco, Mexico. Satellite imagery indicates a a band-like of numerous moderate to strong convection within about 240 nm on the W semicircle of Narda, affecting the southwestern coast of Mexico, including parts of the states of Jalisco and Nayarit, and Las Marias Islands. 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 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... Gentle to moderate W to NW winds prevail north of Costa Rica, 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. Scatterometer data showed moderate to fresh NE winds north of 27N and west of 125W, with corresponding altimeter data indicating seas were 7 to 9 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 12.5N134W along the monsoon trough is supporting fresh to locally strong winds and 8 to 9 ft seas, along with scattered moderate and isolated strong convection. Some gradual development is possible while the system drifts slowly eastward or 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. $$ GR