000 AXPZ20 KNHC 221548 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Oct 22 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... Gulf of Tehuantepec gale warning: minimal gale force winds and seas to 15 ft will continue till late morning, then diminish to near gale force through this evening, then increase again to minimal gale force of 30 to 35 kt winds late tonight and persist through sunrise on Sun. A post-frontal ridge across the Gulf of Mexico will prevail for the next few days maintaining pulses to near gale force through Tue afternoon, with minimal gale conditions developing on Tue evening. A 1007 mb surface low is embedded in the monsoon trough near 11N99W. Although associated winds are currently only 15 to 20 kt, and area of sw swell resulting in combined seas of 7 to 8 ft is observed from 09N to 11N between 96W and 103W. Scattered moderate isolated strong convection is observed within 150 nm either side of a line from 11N98W to 16N103W. Environmental conditions are conducive for tropical cyclone development over the next few days and the low reaches near 12.5N106W on Sun and near 14.5N109W on Mon with winds increasing mainly e of center ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough forms near 13N95W and extends w through a 1007 mb low pressure at 11N99W to 11N104W, then turns nw to 15N110W, then sw through a 1008 mb low pressure at 13.5N115.5W to a 1009 mb low pressure at 10.5N129.5W, then turns nw to beyond TO 14N130W. Scattered moderate isolated strong convection is observed within 90 nm either side of a line from 14.5N112W to 10N120W in association with the low pressure at 13.5N115.5W. Scattered moderate isolated strong convection is observed within 90 nm either side of a line from 10N121W to 10N135W in association with the embedded low at 10.5N129.5W. Scattered moderate isolated strong convection is noted elsewhere within 60 nm either side of a line from 08N100W to 13N108W. Scattered moderate and isolated strong convection is observed along the Pacific coast of Central America within 120 nm either side of a line from 04N79W to 07N83W, within 30 nm of 09N84W and within 90 nm of 12N90W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features for the Gulf of Tehuantepec area. A weak sub-tropical ridge axis extends from nw to se across the offshore zones w of central Mexico. Light to gentle nw flow with combined seas of 5 to 7 ft is expected through this afternoon. The ridge will break down on Sun as a weak trough swings e across the waters n of 29N tonight into Sun. Additionally. a weak trough will extend n along 114W from a tropical low pressure s of the area. Seas are forecast to then build to 7 to 9 ft across the waters n of 30N w of 117W tonight, and continue through early Sun before subsiding. Light southerly winds across the Gulf of California this morning will increase to moderate s winds across the gulf waters n of 19.5N this afternoon, and persist through Sun night with a brief period of fresh winds this evening. Light and variable winds expected through the middle of the week elsewhere n of the Gulf of Tehuantepec area except moderate to occasionally fresh e to se winds are forecast beyond 200 nm. 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 beginning tonight and continuing through Mon morning, except increasing briefly to strong e winds late tonight. Gentle w to nw winds are expected through Sun elsewhere n of the monsoon trough which is meandering e to w along about 09N, while moderate to occasionally fresh sw flow is expected s of the monsoon trough. The monsoon trough should shift s and extends from e to w along 08N on Mon, then shift n to back along 09N during the middle of next week. Combined seas of 4 to 6 ft, primarily in long-period sw swell is expected across the offshore waters for the next 3 to 5 days. REMAINDER OF THE AREA... A ridge extends from 32N140W to 21N115W. Nw swell resulting in combined seas of 7 to 9 ft is currently observed w of a line from 32N124W to 25N140W. These seas are forecast to continue to propagate e and gradually subside to less than 8 ft through late Sun. The ridge will shift s on Sun allowing a weak cold front to move into the far nw waters near 30N140W followed by a stronger front on Sun night which will be accompnaied by a fresh sw to w to nw wind shift with seas building to 8 ft n of 31N w of front. A much stronger cold front will reach 30N140W on Tue accompanied by a strong sw to w to nw wind shift and seas building to 11 ft n of 29n within 300 nm e of the front. Moderate ne trades and 6 to 7 ft seas are expected through tonight s of the ridge and n of the relatively lower pressure within the monsoon trough. Winds and seas will continue to gradually diminish across the waters s of the ridge over the next couple of days except for the tropical low, or tropical cyclone previously mentioned, moving w-nw across the tropics between 100W and 120W. $$ Nelson