000 AXPZ20 KNHC 181602 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Oct 18 2019 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 1545 UTC. ...SPECIAL FEATURES... Tropical Storm Octave is centered near 9.9N 127.1W at 18/1500 UTC moving N at 2 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Satellite imagery from during the morning shows that the earlier convection that was noted has diminished significantly. The latest GOES-17 imagery depicts scattered moderate convection within 60 nm of the center in the western semicircle. Similar convection in small clusters is within 30 nm of a line from 10N125W to 12N126W, and within 30 nm of 10N130W and 09N131W. Octave is forecast to linger over the general vicinity the next several days. Octave is now moving in a northward direction. It is expected to meander or make a gradual clockwise loop during the next few days, and it is forecast to weakened into a remnant low over the weekend. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23 KNHC for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 83W, N of 02N, moving W at 10-15 kt. Scattered moderate convection is noted from 03N to 08N between 80W and 83W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwest Colombia westward to across southern Costa Rica and to 10N86W, then northwestward to 15N95W and westward to 15N105W to low pressure near 15N113W and to 10N124W. It resumes to the west of Tropical Storm Octave near 10N130W and to 10N140W. Scattered moderate to isolated strong convection is seen within 150 nm south of the trough between 96W and 101W, and within 120 nm south of the trough between 135W and 139W. Scattered moderate convection is within 150 nm south of the trough between 101W and 112W, within 120 nm southeast and south of the trough between 112W and 115W and also between 132W and 135W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate to fresh southwesterly monsoonal flow will continue in the Gulf of Tehuantepec zone and vicinity waters through Sat. A set of large northwest to north swell propagating across the Baja California Norte offshore waters will spread southeastward reaching the Revillagigedo Islands by Sat night. Fresh to strong northwest to north winds will continue across the offshore zones of Baja California Norte through the weekend. Moderate to fresh northwest winds will develop in the northern and central Gulf of California Sun night and continue through Tue night. Strong to near gale force north winds will develop in the Gulf of Tehuantepec beginning late Tue night. Expect wave heights there to build to large values late Tue night. A lingering low pressure of 1010 mb is located near 19N105W. The CIRA LPW surface to 850 mb animation imagery confirms the small cyclonic with this low. Satellite imagery shows scattered moderate to isolated strong convection from 18N to 21N between 105W and 109W. This low is forecast to drift south-southeastward and dissipate late Sun night or by early Mon afternoon. Low pressure well to the southwest of the Mexican coast will approach the west-central coast of Mexico by late Sun. This is expected to enhance present moist and unstable atmospheric conditions over these waters leading to additional shower and thunderstorm activity. Some of this activity may contain locally heavy rainfall and strong gusty winds. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to occassionally fresh southwest to west winds will change little through Sat night, then be at fresh to moderate speeds through early next week, except for winds diminishing to gentle speeds north of about 06N late Mon. Southwest will propagate into the waters between the Galapagos and Colombia tonight, then spread northward across the remainder of the forecast waters through the weekend. Wave heights will begin to subside early next week. REMAINDER OF THE AREA... Please read the Special Features section for more details about Tropical Storm Octave. A 1010 mb low pressure is embedded in the monsoon trough near 15N113W. This low is forecast to drift northeastward and weaken to a trough as it approaches the west-central coast of Mexico by late on Sun. A large set of northwest swell is propagating into the northern waters with wave heights above 8 ft to the northwest of a line from 32N115W to 21N140W. An overnight altimeter pass indicates seas near 13 ft near 29N133W. This swell will continue to propagate southeastward, with wave heights in the range of 11-14 ft north of about 29N and between 120W and 123W tonight into Sat, aided by fresh to strong winds which have spread southward from off the southern California coast. The edge of wave heights of 8 ft or greater will reach to 10N and west of 110W by Sat night into Sun. This swell will gradually decay early next week. Otherwise, a ridge extends across the waters N of 20N. Overnight scatterometer data indicates mainly moderate to fresh winds N of 20N and gentle to moderate trades between the monsoon trough and 20N. Outside the northwest swell, wave heights are in the 5-7 ft range. $$ Aguirre