110 AXPZ20 KNHC 070235 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0235 UTC Fri Sep 7 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Hurricane Olivia centered near 19.1N 129.7W at 07/0300 UTC or 1130 nm W of the southern tip of Baja California moving WNW at 12 kt. Estimated minimum central pressure is 948 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Numerous moderate to strong convection is within 120 nm of the center of Olivia, except within 90 nm in the NW quadrant. Olivia is forecast to move W of 140W into the Central Pacific basin Sat night while maintaining hurricane strength. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP2/WTPZ32 KNHC for more details. Low pressure of 1008 mb is near 15N110W. This low is along a tropical wave which has an axis from 06N110W to the low to 20N109W. These features are moving westward at 5 to 10 kt. Scattered moderate and isolated strong convection is within 540 nm in the SW quadrant and 270 nm in the NW quadrant of the low, with scattered moderate convection within 90 nm in the E semicircle. This low may bring increasing winds and seas over a portion of the Pacific waters roughly from 08N to 20N between 108W and 120W Fri through at least Mon. This low has a medium chance of tropical cyclone formation during the next 48 hours. ...TROPICAL WAVES... A tropical wave has an axis extending N of 03N along 82W across western Panama to the western Caribbean Sea, moving westward at around 15 kt. Only isolated showers are seen offshore, with scattered to moderate convection over southern Costa Rica and western Panama. Please see the Special Features section for information on the area of low pressure along a tropical wave that has an axis from 06N110W to the low near 15N110W to 20N109W. A tropical wave has an axis extending from 09N96W to Mexico near 16N96W to the SW Gulf of Mexico, moving westward at around 15 kt. Only isolated showers and thunderstorms are near the tropical wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pressure over northern Colombia near 10N74W to 08N81W to 10N99W to low pressure near 15N110W to 10N119W, then resumes near 14N129W to 13N140W. Scattered moderate and isolated strong convection is from 09N to 11N between 92W and 95W and also from 08N to 12N between 128W and 135W. Scattered moderate to strong convection has developed inland over western Mexico and is propagating offshore from 19N to 26N within 90 nm of shore. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough will meander between the the Gulf of California and the Baja California Peninsula the next few days. A ridge building between Baja California and departing Hurricane Olivia will produce moderate to fresh NW winds W of the Baja peninsula through Fri night. SW swell from a developing tropical low well SW of the offshore waters of southern Mexico will build seas to 7 to 8 ft over the offshore waters of SW Mexico by Sat. Northerly winds will pulse to fresh Offshore of the Gulf of Tehuantepec tonight. Gentle to moderate winds are expected elsewhere over the Mexico offshore waters through the weekend, with seas of 5 to 7 ft over the Pacific waters, and 1 to 3 ft over the Gulf of California. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will meander between 08N and 10N during the next few days. Winds on both sides of the trough axis will be gentle to moderate. Long period SW swell moving into the region will build seas to 8 ft later tonight, at first between Ecuador and the Galapagos Islands, then into the waters of Colombia by Fri night, persisting through much of the weekend. The swell will begin to subside by the end of the weekend into early next week, with another set arriving by late Mon through Tue night. REMAINDER OF THE AREA... Please see the Special Features section for details on Hurricane Olivia, and on developing low pressure near 15N110W. Otherwise, a ridge dominates the forecast waters N of 20N W of 120W, with gentle to moderate winds. Seas generated by Olivia will continue to spread across the waters north of 12N and west of 120W over the upcoming weekend. $$ Lewitsky