767 AXPZ20 KNHC 290946 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 824 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Hurricane Rosa centered near 19.2N 118.2W at 29/0900 UTC moving N or 350 degrees at 8 kt. Estimated minimum central pressure is 971 mb. Maximum sustained wind speed has decreased to 85 kt with gusts to 105 kt. Numerous moderate convection is noted within 60 nm of center. Rosa continues to rapidly weaken. Currently, numerous moderate convection is only noted within 60 nm of the center. Scattered moderate convection is seen elsewhere from 17N to 21N between 116W and 119W. On the forecast track, the center of Rosa will be approaching 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 during this weekend. 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. Satellite-derived wind data indicate that an area of low pressure centered a few hundred miles south of Acapulco, Mexico, continues to produce tropical-storm-force winds, mainly to the northeast and east of the poorly defined center. Environmental conditions are forecast to remain conducive for development over the next several days, and the low is expected to become a tropical storm on Saturday while it moves west-northwestward well offshore the coast of south-central Mexico. The low pressure of 1006 mb is currently located near 12N100W. Numerous moderate and isolated strong convection is from 11N to 13N between 98W and 110W, and from 10.5N to 12.5N between 100W and 103W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from northern Colombia near 08N75W to 10N90W to the low pressure near 12N100W to 11N108W, then resumes SW of Hurricane Rosa from 13N122W to 06N140W. Scattered moderate isolated strong convection is from 10N-14N between 86W-91W. Similar convection is from 06N-08N between 92W-94W, and 08N-10N between 94W-97W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features above for information on Hurricane Rosa and the tropical low near 12N100W. Recent scatterometer data indicate gentle to moderate NW flow west of the Baja California Norte while mainly light to gentle winds are prevailing west of Baja California Sur. Winds and seas will begin to gradually increase across the offshore forecast waters mainly W of 110W tonight as Rosa approaches the area. Tropical Storm conditions are expected Sun night and Mon. 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 Sun Mon. These condition will persist on Sun night into early Mon morning. 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 Tue, 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 dominates the NW forecast waters producing gentle to moderate 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. $$ GR