484 AXPZ20 KNHC 282108 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2108 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...SPECIAL FEATURES... Tropical Storm Miriam centered near 14.1N 136.4W at 28/2100 UTC or 1130 nm ESE of Hilo Hawaii moving W at 11 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Miriam is a sheared tropical cyclone with numerous moderate and scattered strong convection within 210 nm in the SE semicircle. Miriam is no longer forecast to become a hurricane, however some further strengthening to a high end tropical storm is forecast. Miriam is also forecast to move just W of 140W into the Central Pacific basin by Wed night before turning northward. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP5/WTPZ35 KNHC for more details. Tropical Depression Sixteen-E centered near 17.5N 112.5W at 28/2100 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. Numerous moderate and isolated strong convection is within 60 nm in the NE semicircle and 180 nm in the SW semicircle of Sixteen-E. Sixteen-E is forecast to strengthen to a tropical storm late tonight with further strengthening to a hurricane by late Wed night. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for more details. ...TROPICAL WAVES... A tropical wave that was previously analyzed extending southward from the Yucatan Peninsula into the eastern Pacific has been found to have an axis well to the E, N of 02N along 81W, moving W at around 10 kt. Scattered moderate and isolated strong convection is from 04N to 07N between 78W and 85W. A tropical wave axis is N of 05N along 103W moving W at around 10 kt. Scattered moderate and isolated strong convection is from 05N to 17N between 100W and 106W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 09N74W to 09N90W to 09N100W. Scattered moderate and isolated strong convection is from 05N to 08N between 87W and 94W, from 10N to 14N between 90W and 100W. ...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 43N153W 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 N of 20N and the monsoon trough will support moderate to locally fresh trades and 4 to 7 ft seas in mixed swell N of the monsoon trough and west of 120W through the week. $$ Lewitsky