000 AXPZ20 KNHC 211004 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Oct 21 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... Numerous moderate to strong thunderstorms continue within 180 nm across the S semicircle of a small area of low pressure located near 13.5N114W this morning. Global models suggest the potential for this low to become better organized over the next two days as it moves W-NW to NW. However, increasing vertical wind shear across the N portions of the low may limit development, and is expected to create a hostile upper environment by 48 hours. This low has a medium chance of developing into a tropical cyclone over the next 48 hours. A gale warning remains in effect for the Gulf of Tehuantepec. Strong northerly winds are spilling across the Gulf as northerly winds prevail across SW portions of the Gulf of Mexico this morning, to the W of a north to south aligned trough across the eastern Bay of Campeche. N winds have increased to 20-30 kt in recent hours and are expected to reach minimal gale force by around sunrise this morning, and persist through Saturday morning before diminishing to 20-30 kt by Saturday afternoon. Associated seas will build to 8-12 ft by this afternoon. Strong high pressure behind a cold front moving southward across the NW Gulf of Mexico will maintain a strong pressure gradient across the region and persisting northerly flow across the Gulf for the next several days. Expect nocturnal winds to pulse to gale force each night through the weekend with the strongest winds in occurring overnight through the early morning hours, particularly between 0600-1200 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12.5N87W to low pres near 12N95W to 10N104W to low pres near 13.5N114W to low pres near 10.5N131W to 13N140W. Scattered moderate to strong convection is noted within 120 nm N and 150 nm S of the trough between 87W and 120W. Scattered moderate to strong convection is noted within 180 nm across the SW quadrant of low pres near 12N95W. Numerous moderate to strong convection is also noted within 180 nm across the S semicircle of low pres near 13.5N114W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weakening ridge extends SE from near 33N137W to just N of the Revillagigedo Islands at 19N112W. Across the offshore Mexican waters, gentle to moderate NW to N winds were depicted in overnight scatterometer data. The combination of these winds and long period NW swell support seas of 5 to 7 ft along Baja California and 6-7 ft along the mainland coast. Inside the Gulf of California, overnight scatterometer data showed fresh NNW winds throughout most of north and central portions, where seas are likely 3-5 ft, while moderate winds prevailed across S portions. The ridge will weaken today as a cold front approaches the forecast region from the NW, and allow winds and seas to subside inside the Gulf of California. The front is expected to stall and weaken near 28N136W over the weekend, with reinforcing high pres building modestly SE in the wake of the front. A new pulse of NW swell generated behind the front will spread SE and yield seas 8-10 ft across N and NW portions by Saturday, and arrive to the offshore waters of Baja California Norte late Saturday into Sunday, when seas will build 6-8 ft. Seas are expected to subside again by Monday night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Mainly moderate SW winds are noted in scatterometer wind data overnight S of the monsoon trough and across the waters between Ecuador and the Galapagos Islands. Seas of 4-7 ft in mixed SW and NW swell prevail, except to the lee of the Galapagos Islands. Farther N, a small low pressure center has developed near 12N95W, and is producing moderate to fresh SW winds roughly from 05N-12N between 94W and 110W. Seas in this area are in the 7-9 ft range with NW swell. These marine conditions are forecast to persist during the next few days, as the low moves W to W-NW around 10 kt. REMAINDER OF THE AREA... The pres gradient between the ridge to the N and lower pres near the monsoon through is generating an area of fresh to locally strong trade winds from 14N to 27N W of 134W, where seas 7 to 8 ft prevail in mixed NE and NW swell. Winds and seas will continue to gradually diminish across the west-central waters during the next couple of days. $$ Stripling