000 AXPZ20 KNHC 250904 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Oct 25 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...TROPICAL WAVE... A tropical wave is analyzed N of 03N along 99W with scattered moderate isolated strong convection flaring from 07N to 12N within 120 nm of the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the Caribbean coast of Colombia at 09N76W across Panama to the Pacific coast of Costa Rica at 09N84W, then continues W-SW through a tropical wave at 08N99W to 07N109W, then turns NW through an embedded surface low at 13.5N118W, then continues SW through another 1010 mb surface low 11N123W to 09N126W where scatterometer winds indicate a transition to an ITCZ, which then continues W to beyond 09N140W. Isolated moderate to strong convection is observed within 120 nm over the NE quadrant of the surface low at 13.5N118W. Scattered moderate isolated strong within 120 nm over the S semicircle of the surface low at 11N123W. Scattered moderate isolated strong convection is noted elsewhere within 120 nm either side of a line from 08N77W to 10N85W to 09N96W, within 30 nm of 13N109.5W, and within 150 nm either side of a line from 12N134W to 09N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge will meander from 22.5N to 14.597W through the upcoming weekend with light to gentle anticyclonic flow forecast around the ridge, except gentle to locally moderate NW flow is expected W of the Baja California Peninsula through Fri night. Strong N winds and 8 to 15 ft seas, will propagate S into the waters N of 29.5N E of 120W on Mon night. Gulf of California: Light and variable winds will become a gentle NW breeze by Fri morning, and a moderate NW breeze on Fri night, with little change then through Sat night. Gulf of Tehuantepec...Gentle onshore flow is forecast during the daylight hours, and gentle to locally moderate offshore drainage expected nocturnally through late Sat. Model guidance suggests the next strong to near gale northerly drainage event will begin on Sat evening, with gale force conditions possible on Mon evening through Tue morning with seas building to 14 ft downstream of the gulf waters near 14.5N95.5W, and seas 8 ft or greater reaching as far S as 11.5N97W on Mon night. Guidance indicates the northerly winds will diminish to 20 kt or less, and seas will subside to less than 8 ft late Wed night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Fresh NE flow, with 5 to 8 ft seas, will diminish to a moderate breeze this afternoon with little change through late Sun when fresh NE flow is forecast to resume, and then continue through late Mon. Light to gentle variable winds, and 3 to 6 ft seas are forecast elsewhere N of the monsoon trough through early next week, while moderate southwesterly monsoonal flow, with 5 to 7 ft seas, is forecast S of the monsoon trough. REMAINDER OF THE AREA... A 1011 mb low near 13.5N118W will drift W for about a day before turning SW and dissipating within the monsoon trough on Fri. A 1011 mb surface low analyzed along the monsoon trough at 11N123W is expected to move W and lose identity within the trough by Sat. A surface high meandering over the far NW waters is forecast to shift NE to near 32N133W by early Fri, and lift N of 32N on Fri night. Mixing swell will result in a large area of 7 to 9 ft seas N of the ITCZ and W of 130W through Sat morning. NW swell in the form of 7 to 9 ft seas, will reach along 28N between 122W and 130W on Fri, then subside to less than 8 ft Fri night. A cold front will reach a line from 32N137W to 29N140W on Sat night followed by 8 to 10 ft seas in long period NW swell. Although the front will wash out on Sun, the associated post- frontal NW swell will propagate E across the discussion area reaching a line from 32N127W to 17N140W on Sun night, and reach from the northern Baja California Peninsula to near 10N140W on Mon night, just as a surge of strong northerly winds accompanied by 10 to 15 ft seas, moves into the waters N of 29.5N between 118W and 125W. $$ Nelson