000 AXPZ20 KNHC 062153 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2109 UTC Thu Dec 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 2045 UTC. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 05N92W to 06N99W. The ITCZ continues from 06N99W to 10N118W. The ITCZ resumes from 10N124W to 10N128W to 08N133W to beyond 08N140W. Scattered moderate and isolated strong convection is observed from 05N to 08N between 88W and 90W. An area of convergent trade winds is generating scattered moderate and isolated strong convection from 11N to 17N between 103W and 110W. ..DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: High pressure ridging SW across the Gulf of Mexico will maintain strong N winds over the Gulf of Tehuantepec through Fri night, then the high will will have moved far enough NE to allow the ridge over the western Gulf to break down and winds to subside. The next gap event will begin on Sun morning as strong high pres builds S along the eastern slopes of the Sierra Madre Oriental behind s cold front. Strong gale conditions are expected to develop Sun evening, then persist through Wed night. Gulf of California: A cold front will sweep SE through the northern gulf waters tonight, then over the southern gulf waters by Fri afternoon. Fresh N flow that will spread SE across the north and central Gulf waters Fri evening through Sun evening. Winds are then expected to diminish Mon. Elsewhere: A weak 1019 mb high is centered over the waters W of Baja California Sur near 22N117W, ahead of an approaching cold front, which extends from 30N115W to 23N121W. Moderate S flow is observed N of 26N within 120 nm E of the front, and is arriving along the coast of Baja California Norte. The front will quickly move SE across the region, and reach from Baja California Sur over the southern Gulf and through Cabo San Lucas by Fri evening, and then dissipate near Las Tres Marias by Sat morning. Long-period NW swell following in the wake of the front will cause seas to build to between 6 and 9 ft overnight, and between 7 and 10 ft across the northern and central waters on Fri as the swell reaches Baja California Sur. High pres will then build across the Baja offshore waters Fri night and Sat behind the front to produce moderate N wind flow as seas peak between 8 and 10 ft for all of the Baja waters. Seas will then begin to subside from the N, subsiding between 5 and 7 ft by Sun evening. The next round of long-period NW swell, in the form of 7 to 9 ft seas, will reach 32N120W on Mon, then propagate S across the waters W of the entire Baja Peninsula on Tue. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Narrow and intermittent volcanic ash plumes, originating over interior Guatemala, has been observed on satellite imagery intermittently overnight spreading SW over the Pacific coast of Guatemala but was likely not detected at the surface. Gulf of Papagayo...Nocturnal pulses of fresh to locally strong NE winds, and 6 to 8 ft seas, are expected through Fri evening, and will extend as far W as 11N91W on Thu. Elsewhere: The monsoon trough will meander between 08N and 10N with light to gentle variable flow, and 3 to 6 ft seas, forecast N of the monsoon trough, and moderate southwesterly monsoonal flow, and 3 to 6 ft seas, forecast S of the monsoon trough. REMAINDER OF THE AREA... Long period NW swell, manifesting in the form of a large area of 8 to 13 ft seas, is forecast to continue propagating SE to encompass almost all of the forecast waters W of 110W by Sat afternoon. This area of swell will decay by Mon. Trade-wind waves and swell will support a large area of8 to 10 ft seas S of 17N and W of 105W by Sun night. Another cold front will reach 32N137W on Fri accompanied by a moderate wind shift. A stronger cold front will reach 32N140W on Sat evening accompanied by a fresh wind shift and large post- frontal NW swell. $$ CAM