000 AXPZ20 KNHC 280952 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Sep 28 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... A large area of disturbed weather extends from the far western Caribbean and Central America westward across the offshore waters and adjacent land areas between 06.5N and 20N to 110W. Strong SW monsoonal winds across portions of this area are transporting abundant tropical moisture into the area and across SE Mexico and Central America, where scattered clusters of strong thunderstorms are occurring this morning. In addition, a 1006 mb low pressure center is analyzed along the monsoon trough near 13.5N98.5W moving NW at 3 kt. Environmental conditions are very favorable for a tropical depression or a tropical storm to form within this area during the next day or so, while it moves west- northwestward to northwestward at near 10 kt, and passes along or just offshore of the southwestern coast of Mexico. Interests along this portion of the coast should monitor the progress of the disturbance, since tropical storm watches or warnings may be required at any time on Saturday. Regardless of tropical storm development, heavy rainfall, with the possibility of flash flooding and mudslides, is expected across SE Mexico and the western half of Central America during the next few days. A gale warning has been issued for the offshore waters from Acapulco to Manzanillo beginning this evening in anticipation of further development. The latest Tropical Weather Outlook gives this system a high chance of tropical cyclone formation during the next 48 hours. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N74W TO 14N87W TO 14.5N94W TO low pres near 13.5N98.5W TO 14.5N105W TO 17.5N120W TO beyond 12.5N140W. Scattered to numerous moderate to strong convection is noted from 06.5N TO 14N between 83W AND 91.5W, and from 10N TO 19.5N between 91.5W AND 108W. Scattered moderate to strong convection is noted within 180 nm S of the trough between 118W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Overnight scatterometer data revealed moderate NW winds across the Baja California Norte offshore waters, while fresh northwest winds were observed south of Punta Eugenia to Cabo San Lucas. Seas are running 5-7 ft across these waters in mixed NW and SW swell, except around 8 ft from Cabo San Lucas to the Revillagigedo Islands. A weak cold front offshore of southern California will sink southward across the offshore waters of Baja California Norte today through Sun evening before dissipating, and will maintain moderate winds across the Baja waters. High pressure will build modestly across the waters in the wake of the front, and act to freshen NW winds Sun evening through Mon. Moderate NW winds continue farther SE to the waters offshore of Cabo Corrientes to near 15N107W. Strong W to SW winds prevail elsewhere south of the monsoon trough and are aiding in producing very active and strong convection to the east of 110W. Scattered to numerous showers and thunderstorms, with strong gusty winds will continue across the Mexican coastal waters, mainly southeast of Manzanillo through Sun. This weather will shift NW tonight through Sun associated with the expected development of a low pressure system mentioned above, and shift further NW to the area between Acapulco and Las Tres Marias through Sun afternoon, and shift further NW into the southern Gulf of California Manzanillo Sun night through Mon. Please refer to local statements issued by the Meteorological Service of Mexico for further details. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong southwest to west monsoon flow will support scattered showers and thunderstorms across the offshore waters from Costa Rica to Guatemala and El Salvador today. This strong monsoonal flow will build seas to 8 to 12 ft through tonight, while wave heights remain 8 or 10 ft across the coastal waters of Nicaragua and northern Costa Rica through the weekend. REMAINDER OF THE AREA... A ridge dominates the forecast waters N of 20N W of 110W producing mainly light to gentle winds. Moderate to fresh NE winds are noted over the NW corner of the area behind a weakening frontal boundary sinking slowly southwards toward 30N. Long-period north swells in the wake of the front are propagating across the waters N of 24N W of 125W, building seas to 10 ft. Seas will gradually subside to 8 ft in this area on Sun. Elsewhere, gentle NE to E tradewinds prevail across the tropical waters between 20N and the monsoon trough, and to the W of 110W. Little change is expected through the weekend. Seas will generally remain 5-7 ft in mixed swell during this time. $$ Stripling