000 AXPZ20 KNHC 192203 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1937 UTC Wed Oct 19 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...SPECIAL FEATURE... A gale warning remains in effect for the Gulf of Tehuantepec. This gap wind event will be associated with a cold front moving S through the western Gulf of Mexico Thursday night through Friday night. N winds of 25-30 kt will begin to surge into the Tehuantepec area tonight. Winds are forecast to continue increasing to minimal gale force by Friday morning with seas building to 9-13 ft by Friday afternoon. Model guidance has trended downward with respect to the peak intensity of this event but this event will be long lived with winds to gale force possible through at least Wednesday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N104W to 14N111W to 1007 mb low pres near 13N114W to 10N122W to 13N136W to a second low pres of 1008 MB near 12N139W. The ITCZ continues from 12N139W to beyond 12N140W. Scattered moderate convection is noted from 10N to 13N between 105W and 111W...and from 10N to 12N between 115W AND 120W. A surface trough reaches from 12N86W to 15N93W. Scattered moderate and isolated strong convection is seen from 09N to 16N between 85W and 100W. This area includes the Gulf of Tehuantepec. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge extends SE from 32N133W to near the Revillagigedo Islands at 18N109W. The pres gradient between the ridge and low pres over western Mexico is generating fresh to strong N winds across the waters N of 27N between 120W and 125W. Satellite-derived sea height data from 1055 UTC shows seas in this area between 9 and 11 ft. Moderate to fresh NW to N winds prevail W of Baja California. The combination of these winds and long period NW swell support seas of 8 to 10 ft W of Baja California Norte, and 6 to 8 ft seas W of Baja California Sur. The high pres center will shift SW in about 24 hours and the ridge will weaken through Friday as a cold front approaches the region. The front is expected to stall and weaken near 30N140W by late Friday. The long period swell currently arriving will subside during the next few days. A new batch of swell of 8 to 9 ft generated N of the front is forecast to arrive offshore Baja California Norte over the weekend. Winds are expected to increase across the northern part of the Gulf of California tonight as high pres builds across the Great Basin. By Thursday morning...expect NW winds of 20-25 kt and seas of 5-6 ft N of 30N, and NW winds of 15-20 kt with seas of 4-5 ft across the central waters, mainly N of 26N. Moderate to fresh winds are forecast to blow across the Gulf of California or Sea of Cortez by Thursday evening until early Friday morning. Farther S...a gap wind event, reaching minimal gale force, is expected to begin across the Gulf of Tehuantepec tonight. See Special Features section for details. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh S to SW winds are noted satellite-derived wind data S of 10S. Mainly light to gentle winds continue N of 10N. Seas generally range between 5 and 8 ft. A mix of NW and SW swell predominate W of 90W, while SW swell predominate E of 90W. These conditions are forecast to prevail over the next few days. REMAINDER OF THE AREA... A pair of low pres systems are observed within the monsoon trough. The easternmost one is near near 13N114W. An area of fresh to locally strong SW winds on the SE side of the low is expected to accompany this system as it drifts NW to N. Some development of this system is possible during the next several days as it drifts N or NW. The westernmost low pres is near 12N139W. This system remains disorganized. The pres gradient between the ridge to the N and this low pres is generating an area of fresh to strong winds from 14N to 17N W of 133W. This low is forecast to move W of area tonight. As a result, winds and seas will diminish across the west-central waters. Currently, seas of 8-11 ft, primarily in NW swell, dominate the forecast region W of a line from 24N135w to 13N123W to 10N137W and N of a line from 20N114W to 20N121W to 28N128W. Seas will gradually subside over the next couple of days, but another set of long period NW swell will reach the NW corner by late Friday. Elsewhere, the combination of SW winds S of the monsoon trough and NW swell will support seas of 8-10 ft within an area bounded by a line from 15N110W to 10N94W to 03N105W to 10N121W to 15N110W. In addition, cross-equatorial SW swell of 8-9 ft are propagating NE between 92W and 112W affecting the waters S of the Equator. Seas in this area will subside below 8 ft late Thursday. $$ cam