704 AXPZ20 KNHC 072214 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Hurricane Olivia is centered near 20.5N 133.9W at 2100 UTC or about 1273 nm E of Hilo Hawaii, moving WNW at 14 kt. Estimated minimum central pressure is 968 mb. Maximum sustained wind speed is 95 kt with gusts to 115 kt. Satellite imagery this afternoon shows Olivia maintaining a large 30 nm wide eye, with numerous moderate to strong convection occurring from 15 to 60 nm across the NW and from 15 to 90 nm across the SE semicircles. Olivia is forecast to continue moving WNW and gradually weaken slightly, and will pass across 140W and into the Central Pacific basin Sat night while maintaining minimal hurricane strength. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP2/WTPZ32 KNHC for more details. Elongated low pressure of 1008 mb is analyzed near 15N113W moving westward around 5 kt. This main surface low is along the northern end of an elongated cyclonic circulation associated with a tropical wave which along about 113W. An afternoon ASCAT pass showed winds of 15 to 25 kt occurring within 150 nm across the NW quadrant, where seas were 7 to 8 ft. Associated scattered moderate to strong convection is within 180 nm either side of a line from 18N118W TO 10N117W. This system is expected to bring increasing winds and seas over a portion of the Pacific waters roughly from 08N to 20N between 108W and 125W Fri through at least Mon, as it gradually becomes better organized. This low has a high chance of tropical cyclone formation during the next 48 hours. ...TROPICAL WAVES... A tropical wave has an axis along about 87W north of 04N across Central America to the Gulf of Honduras, moving westward at 10 to 15 kt. Widely scattered showers and thunderstorms are currently accompanying this tropical wave, mainly along the monsoon trough. A tropical wave has an axis along about 99W to the north of 07N, moving westward at 10 kt. Moderate to strong convection is scattered about the area from 06.5N to 14N between 95W and 104W. Please see the Special Features section for information on the area of low pressure along a tropical wave at 113W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from low pressure over northern Colombia near 10N74W to 08N82W to 10N97W to low pressure near 15N113 TO 11N118W, then resumes from 14N132W to 13N137W. Scattered moderate to strong convection is noted within 180 nm s of the trough between 132W and 138W. Scattered moderate to strong convection that developed inland overnight across western Mexico has continues across the offshore waters near the entrance to the Gulf of California this afternoon, but currently only covers the area within 120 nm S through E of Cabo San Lucas. ...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 early Sat. SW swell from a developing tropical low SW of the offshore waters of southern Mexico will spread north and northeastward to build seas across the offshore waters to 7 to 8 ft 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 generally 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 cross equatorial SW swell propagating into the region today has built seas to near 8 ft between Ecuador and the Galapagos Islands, and will spread into the waters of Colombia tonight, persisting through much of the weekend. The swell will begin to subside by the end of the weekend into early next week, with another pulse 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 15N113W. Otherwise, a ridge drapes across Olivia and dominates the forecast waters N of 20N W of 120W, producing gentle to moderate easterly winds south of 30N and west of 122W. Seas generated by Olivia will continue to spread across the waters north of 12N and west of 120W over the upcoming weekend. $$ Stripling