296 AXPZ20 KNHC 281500 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1500 UTC Tue Aug 28 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 1200 UTC surface analysis and satellite imagery through 1430 UTC. ...SPECIAL FEATURES... Tropical Storm Miriam centered near 14.2N 135.4W at 28/1500 UTC or 1180 nm ESE of Hilo Hawaii moving W at 12 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Numerous moderate and scattered strong convection is within 240 nm in the SE semicircle and within 90 nm in the NW semicircle of Miriam. Tropical Storm Miriam is forecast to strengthen to a hurricane Wed night while moving W of 140W into the Central Pacific basin. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP5/WTPZ35 KNHC for more details. Tropical Depression Sixteen-E centered near 17.1N 111.8W at 28/1500 UTC or 360 nm SSW of The Southern Tip Of Baja California moving WNW at 9 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate and isolated strong convection is within 150 nm in the SW semicircle of the tropical depression. The tropical depression is forecast to strengthen to a tropical storm tonight, and then to a hurricane on Thu. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for more details. ...TROPICAL WAVES... A tropical wave axis is N of 05N along 91W moving W at around 15 kt. Scattered moderate and isolated strong convection is described in the monsoon trough section below. A tropical wave axis is N of 04N along 101W moving W at around 10 kt. Scattered moderate convection is within an area bounded by 19N104W to 10N95W to 04N96W to 08N105W to 19N104W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia 09N74W to 09N90W to 09N100W then resumes from 14N113W to 11N127W. Scattered moderate and isolated strong convection is from 03N to 08N between 77W and 90W and from 10N to 12N between 91W and 95W. Scattered moderate convection is from 10N to 12N between 115W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on newly formed Tropical Depression Sixteen-E. A ridge extends southeast from a weakening 1035 mb high pressure near 43N150W through NW of the Revillagigedo Islands. The associated pressure gradient between the high and a persistent trough across the Baja California Peninsula will continue to support moderate to occasionally fresh NW winds funneling along the coast of Baja California Norte through Fri, with seas generally in the 4 to 6 ft range. Winds will diminish on Sat as the pressure gradient weakens. Nocturnal offshore flow in the Gulf of Tehuantepec will pulse to moderate the next several nights, increasing to moderate to fresh Thu night. Otherwise, with low pressure over northern Mexico, light to gentle southerly flow will dominate over the Gulf of California the entire week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will linger along 09N/10N during the next few days. Winds on both sides of the trough axis will generally be light to moderate. The main exception to this will be over the Gulf of Papagayo where nocturnal offshore gap winds will pulse to moderate to fresh. REMAINDER OF THE AREA... Please see the Special Features section for information on Tropical Storm Miriam. Elsewhere, the pressure gradient between ridging across the waters north of 20N and the monsoon trough will support moderate to locally fresh trades and 4 to 7 ft seas in mixed swell north of the monsoon trough and west of 120W through the week. The exception will be from 17N to 21N W of 138W where the remnants of a surface trough are generating fresh to locally strong NE winds with seas to 8 ft. The associated winds and seas will shift W of the area this afternoon. $$ Lewitsky