000 AXPZ20 KNHC 150235 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 023 UTC Sun Oct 15 2017 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong winds prevail over the Gulf of Tehuantepec. Winds will pulse to near gale force overnight with the added component of nocturnal drainage flow. High pressure building over eastern Mexico in the wake of a cold front moving across the Gulf of Mexico will tighten the pressure gradient over the region. This will increase gap winds funneling through the Chivela pass into the Gulf of Tehuantepec. Winds will reach minimal gale force early Monday morning, and continue through at least midweek. Seas will reach 13-15 ft during the overnight hours of this event, when winds will peak near 40 kt. Low pressure of 1007 mb is embedded within the monsoon trough near 15N115W. Scattered showers and isolated thunderstorms associated to this feature are noted within 120 nm east semicircle of the low. There is currently a high probability that this low will develop into a tropical cyclone within the next 48 hours. Please refer to the latest Tropical Weather Outlook for more information. ...TROPICAL WAVES... The axis of a tropical wave axis analyzed near 88W N of 04N, moving westward near 17 kt. Scattered moderate convection is noted over the southern portion of the wave from 06N to 08N between 86W and 89W. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N86W to 09N94W to low pres near 15N115W to low pres near 10N130W to 09N135W. The ITCZ extends from 09N135W to 09N140W. Scattered moderate convection was noted from 06N to 08N between 86W and 89W. Scattered moderate isolated strong convection was noted from 08N to 11N between 91W and 96W. Scattered moderate isolated strong convection was noted from 09N to 18N between 111W and 118W. Scattered moderate convection was noted from 10N to 12N between 126W and 129W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends across the waters off Baja California. Outside of the Gulf of Tehuantepec, gentle to moderate winds prevail over the open forecast waters with light winds over the Gulf of California. Seas are in the 6-7 ft range over the open waters, and 1-3 ft over the Gulf of California. The ridge will remain in place this weekend with little change in winds. High pressure building over the Great Basin region will help to strengthen winds over the northern Gulf of California early Sunday, and continue through early in the week. The area of high pressure will then shift eastward which will help to decrease winds over this area. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh offshore winds will prevail across the Papagayo region through midweek with seas of 5-7 ft. Light and variable winds and seas of 4 to 5 ft seas prevail elsewhere N of 09N. Gentle to moderate SW to W winds and 5 to 7 ft seas will prevail across the waters S of 09N through early next week before seas subside to 3-5 ft by midweek. REMAINDER OF THE AREA... Please see special features section above for more information on low pressure centered near 15N115W. Elsewhere, high pressure of 1036 mb centered NW of the area near 40N148W extends a ridge southeast to near 25N115W. The pressure gradient has relaxed over the forecast waters, and winds have diminished to 20 kt or less. Northerly swell continues to propagate across the waters, with seas of 8 to 11 ft west of a line from 30N121W to 20N122W to 12N122W. The swell will subside, with seas of 8 to 9 ft confined to the waters from 11N to 16N west of 133W by early next week. Cross equatorial southwesterly swell will continue to propagate across the south- central waters, particularly S of 15N between 100W- 120W over the next couple of days. $$ AL