524 AXPZ20 KNHC 292135 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2134 UTC Sat Sep 29 2018 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... Hurricane Rosa centered near 21.4N 118.7W at 29/2100 UTC or 430 nm SSW of Punta Eugenia Mexico moving N at 10 kt. Estimated minimum central pressure is 968 mb. Maximum sustained wind speed is 90 kt with gusts to 110 kt. Numerous moderate to strong convection is noted within 120 nm of the center. Rosa will approach central and northern Baja California on Monday as a tropical storm. Swells generated by Rosa will affect portions of the coasts of southwestern Mexico, most of the Baja California Peninsula, and southern California through Monday. These swells are likely to cause life- threatening surf and rip current conditions. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP5/WTPZ35 KNHC for more details. Farther south, Tropical Storm Sergio is centered near 12.1N 102.8W at 29/2100 UTC or 330 nm SSW of Acapulco Mexico moving W at 10 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Convection is increasing in the vicinity of Sergio as it becomes better organized. Numerous moderate to strong convection is noted within 240 nm of the center. An earlier scatterometer satellite pass indicated the strongest winds were still displaced somewhat on the eastern side of the center. ...TROPICAL WAVES... A tropical wave extends along 90W north of 04N through the border of El Salvador and Guatemala. No significant convection is noted at this time. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07N78W to Tropical Storms Sergio. The intertropical convergence zone reaches from 09N128W to 06N140W. No significant convection other than within 240 nm of Sergio. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features above for information on Hurricane Rosa and Tropical Storm Sergio. Over open waters outside of the immediate areas near Rosa and Sergio, gentle to moderate NW flow is noted. In the Gulf of California, gentle to moderate southerly winds are expected through Sun night. The southerly flow will increase to near gale force N of 27N thereafter, with tropical storm conditions possible N of 29N Mon night and Tue from Rosa. In the Gulf of Tehuantepec, fresh to strong northerly winds are expected with seas building to 9 ft tonight into early Mon. Fresh to briefly strong pulses will occur also Mon night into early Tue in the wake of the tropical wave passing through the region. Various scatterometer satellite passes have confirmed there is a large area of swell generated from Hurricane Rosa covering much of the open waters southwest of Baja California. Seas in the form of mixed swell in excess of 8 ft are observed over most of the ocean from 10N to 25N between 110W and 130W. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will meander between 09N and 12N through mid week, with gentle to moderate winds expected on either side of the trough axis. Moderate to fresh E nocturnal drainage flow is expected in the Gulf of Papagayo through Sun night. REMAINDER OF THE AREA... See Special Features above for information on Hurricane Rosa. A weak ridge, anchored by a 1018 mb high centered near 25N140W, dominates the waters north of 20N and west of Rosa producing gentle to moderate west winds N of 23N W of 120W, and moderate to fresh trades S of 23N. A weak cold front will sweep across the waters north of 27N through early next week, accompanied by a W to NW wind shift. NW swell may propagate into the N central waters early next week, mixing with shorter period swell generated from Rosa, and later in the week from Sergio as it continues westward to the south of the Revillagigedo Islands. $$ Christensen