908 AXPZ20 KNHC 062130 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2130 UTC Thu Sep 6 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 Olivia centered near 18.6N 128.5W at 06/2100 UTC or 1070 nm W of the southern tip of Baja California moving WNW at 12 kt. Estimated minimum central pressure is 954 mb. Maximum sustained wind speed is 110 kt with gusts to 135 kt. Numerous moderate to strong convection is within 90 nm W semicircle and 120 nm E semicircle. Olivia is forecast to maintain its intensity tonight, then begin to gradually weaken Fri, while continuing on a west-northwest track. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC for more details. ...TROPICAL WAVES... A tropical wave has an axis extending from 04N94W to 21N93W, moving westward at around 15 kt. Scattered moderate convection is from 08N to 15N between 93W and 100W. A tropical wave has an axis extending from 07N109W through a 1008 mb surface low near 14.5N108.5W to 20N108W, moving westward at around 15 kt. Scattered moderate and isolated strong convection are from 13N to 18N between 106W and 112W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N77W to 09N95W to low pressure near 14.5N108.5W to 09N120W, then resumes from 14N126W to beyond 12N140W. Aside from convection associated with the tropical waves, scattered moderate and isolated strong convection are from 05N to 08N between 84W and 89W, from 10N to 16N between 112W and 118W, and from 08N to 12N between 128W and 140W. ...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. 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. Seas will build across the region as long period SW swell crosses the equator, bringing seas to 8 ft by Fri offshore Colombia, Ecuador, and the Galapagos Islands. This swell will likely persist through Sun. REMAINDER OF THE AREA... Please see the Special Features section above for details on Hurricane Olivia. 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. A developing tropical low well SW of southern Mexico 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. $$ Latto