000 AXPZ20 KNHC 231015 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Oct 23 2016 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. ...SPECIAL FEATURES... The low pressure center moving W-NW and away from the Tehuantepec region the past 24 hours has improved in organization overnight, and this system has been initiated as Tropical Depression Twenty-E, located near 13.1N103.6W at 0900 UTC, moving W-NW or 290 deg at 14 KT. Maximum sustained winds are 30 kt with gusts to 40 KT, and minimum central pressure is 1007 mb. Satellite and microwave imagery overnight have shown increased deep convection near and within 210 nm across the NW semicircle of the center. Also, a partial ASCAT pass overnight showed winds to 28 kt occurring within 120 nm across the NE quadrant. Oceanic and atmospheric conditions appear favorable for gradual strengthening of the T.D. during the next few days, as it moves W-NW at 10-15 kt, and is expected to reach hurricane strength within 48 hours. Based on the current forecast track, strong to tropical storm force winds will brush across outer portions of the offshore waters from SW of Acapulco to Cabo Corrientes through Monday afternoon, then the cyclone will move slightly more westward and remain outside the offshore waters of Baja California Sur Monday night and Tuesday. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25 for more details. A gale warning remains in effect for the Gulf of Tehuantepec. A narrow north to south aligned ridge across eastern Mexico will maintain strong northerly winds across the Gulf of Tehuantepec for most of the upcoming week. Winds are expected to increase late each night through early morning to minimal gale force, then diminish to 20-30 kt during the day. Peak seas downstream of these gales will build to around 9-12 ft by sunrise each morning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N74W to 10N86W to 09N92W to T.D. TWENTY-E near 13.1N103.6W to low pres near 15N115.5W to low pres near 13.5N128W to beyond 11.5N140W. Widely scattered to scattered moderate to strong convection is noted from 02.5N to 09.5N E of 85W. Scattered moderate to strong convection is noted within 120 nm N and 180 nm S of the trough between 93W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... For the Gulf of Tehuantepec area, see special features section above. A weak sub-tropical ridge axis extends from NW to SE across the offshore waters of Baja California Sur to near 23N113W. Light to gentle NW winds are expected across the Pacific waters of Baja California today before weak troughing develops just offshore of Baja California Sur tonight to produce light and variable winds. Combined seas of 4 to 6 ft in NW swell are expected this morning before seas build to 5-8 ft this afternoon through Mon in a new pulse of NW swell. NW winds will freshen modestly Mon night through Tue as the ridge strengthens slightly. Inside the Gulf of California, mainly gentle southerly winds are noted based on scatterometer and surface data. This general wind direction will persist on Sun, then light and variable winds are expected on Mon. Light and variable winds are also expected elsewhere within about 100 nm of the Mexican coast from W of the Gulf of Tehuantepec through tonight, except for freshening E to SE winds across the outer waters between Acapulco and Cabo Corrientes due to T.D. Twenty-E. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: fresh to locally strong NE winds are expected across and just downstream of the Gulf of Papagayo early Sun morning and again on Monday morning. Gentle to moderate S to SW winds are noted S of 05N, while gentle to moderate W to NW winds are N of 05N. Combined seas of 4 to 6 ft, primarily in long- period SW swell dominate the offshore waters. These marine conditions will persist over the few days. REMAINDER OF THE AREA... A weak ridge dominates most of the north waters N of 20N W of 118W. Under the influence of this system, mainly gentle to moderate winds are noted per scatterometer data. Winds will increase to 15-20 kt near the monsoon trough due to the presence of a string of weak low pres systems along the trough, and their associated convection. A new pulse of long period NW swell is spreading SE across the NW waters. This swell is expected to reach the waters of Baja California today then gradually subside below 8 ft by Mon night. A cold front will enter the NW waters near 30N140W tonight and will move across the NW waters on Monday, stretching from 30N133W by Monday evening. This front will be reinforcing by a second cold front reaching the same area on Tue. The merging cold front is forecast to extend from 30N134W to beyond 26N140W by Tue night. $$ Stripling