000 AXPZ20 KNHC 231545 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURES... Tropical Depression 20-E: centered near 13.5N 105.0W or about 385 sm s of Manzanillo Mexico at 1500 UTC, is 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. Currently scattered strong convection is observed along a band over the w semicircle within 120 nm either side of a line from 17.5N102W to 10.5N107W. Oceanic and atmospheric conditions are favorable for gradual strengthening and the system is forecast to reach minimal tropical storm force near 14.1N 106.6W at 0000 UTC on Mon, then continue to strengthen reaching minimum hurricane force early Tue. Although the forecast track keeps the tropical storm force winds beyond 250 nm from the coast, strong, mainly ne to e winds are expected to pass across the offshore waters beyond 200 nm from 13N to 17N today through midday on Mon when the cyclone turns more westward. For additional details, refer to the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25. Gulf of Tehuantepec gale warning: minimal gale force winds and seas to 14 ft will continue till late morning, then diminish to strong to near gale force strength this afternoon with these conditions continuing through late morning on Mon. Guidance has backed off the strength of the drainage flow, and now expect a 30 kt max through early Thu, and then minimal gale force again late Thu. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough forms over the Gulf of Panama near 09N79W and extends sw to 07N81W, then turns nw to 12N96W where it loses identity in the broad cyclonic circulation associated with tropical cyclone 20-E. Scatterometer winds indicate that the monsoon trough forms again w of 20-E at 15N110W, and extends w through an embedded 1010 mb low at 16N115W to another embedded low at 12.5N127W 1009 mb, with the trough continuing sw to 11N133W, then nw to beyond 12N140W. Isolated moderate and strong convection is over and along the eastern segment of the monsoon trough within 120 nm either side of a line from 05N77W to 12N95W. Scattered moderate to strong convection is noted along the w segment of the monsoon trough within 60 nm either side of a line from 13N110W to 16N114W. Scattered moderate isolated strong is noted within 90 nm either side of a line from 13.5N125W to 11N131W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features for the Gulf of Tehuantepec area and for T.D. 20-E affecting the far offshore waters. A 1015 mb surface high is analyzed at 26N120W surrounded by light anticyclonic winds across the waters w of the Baja Peninsula. Combined seas are in the 3 to 6 ft range, except 7 to 8 ft n of 28N w of 118W due to long period nw swell that will subside below 8 ft tonight. The high will shift w leaving a ridge extending nne to southern California on Mon resulting in light n flow to the n of 21N. Light to gentle southerly winds expected across the Gulf of California through tonight except gentle to moderate winds to the n of 30N. The low level winds will veer to the n late tonight and Mon. Light to gentle winds expected elsewhere n of the Gulf of Tehuantepec area, except moderate to fresh e to se winds are forecast beyond 200 nm, with a small area of strong winds at 250 nm seaward across offshore zones PMZ025 today and across the se portion of PMZ023 late tonight into Mon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to fresh ne winds are expected across and just downstream of the Gulf of Papagayo tonight into early Mon morning. Gentle nw to n winds are expected through mid week elsewhere n of the monsoon trough which is meandering e to w along about 09N, while moderate sw flow is expected s of the monsoon trough except increasing to fresh across the waters beyond 200 nm. Combined seas of 3 to 6 ft, primarily in long-period sw swell is expected across the offshore waters for the next 3 days. REMAINDER OF THE AREA... See special features concerning TD 20-E. A ridge will meander across the e portion blocking the eastward progression of a series of weak cold fronts moving into the nw waters. A cold front on Mon will be accompanied by a fresh sw to w to nw wind shift with seas building to 8 ft n of 31N just ahead and everywhere and the discussion area w of front. Southwesterly winds will increase to 20 to 25 kt with seas building 8 to 12 ft early Tue near 30N140W, with these conditions spreading e to along 130W Tue night as the cold front enters the area. The front will reach along 125W to the n of 27N early Fri, then begin to stall and weaken. $$ Nelson