000 AXPZ20 KNHC 022112 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Oct 2 2017 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 2100 UTC. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough is over Central America and extends from southern Guatemala to 1006 mb low pres near 13N94W to 15N110W to 13N110W to 11N122W to 1008 mb low pres near 13N129W to beyond 10N140W. Scattered moderate isolated strong convection is from 10N to 13N between 88W and 92W. Scattered moderate to strong convection is from 11N to 15N between 94W and 101W. Scattered moderate convection is from 10N to 12N between 126W and 134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gap winds will pulse to fresh to locally strong over the Gulf of Tehuantepec during the overnight and early morning hours tonight into Tuesday as a ridge persists across the western Gulf of Mexico and the eastern slopes of the Sierra Madre Mountains. Winds and seas will increase across the Gulf of Tehuantepec area Wednesday night through Friday night as the area of low pressure currently located near the Gulf of Tehuantepec strengthens. Environmental conditions are expected to be conducive for some development over the next few days while the system moves slowly west-northwestward or westward. The combination of winds associated with the developing low pressure and long period SW swell, will generate a large area of seas of 8 to 12 ft or possibly higher S of 13N between 90W and 130W on Wednesday. This swell event will reach the offshore waters of Mexico, south of Cabo Corrientes on Thursday and beyond. Elsewhere, a ridge dominates the waters west of the Baja California Peninsula producing gentle to moderate northerly winds and seas of 4 to 5 ft. Northerly swell propagating into the waters west of Baja California Norte, with seas of 7 to 9 ft will persist on Tuesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... An active monsoon trough is currently across parts of Central America and adjacent waters with widespread convection. The trough will remain close enough to the coast, either inland or just offshore, to produce additional active convection over portions of Central America as well as the adjacent coastal waters during the next few days, with locally heavy rain possible. Fresh to strong SW to W winds and seas of 8 to 11 ft are expected to affect the waters beyond 200 nm off the coast from Nicaragua to Guatemala through Wednesday. Winds and seas will also increase across the offshore waters of Panama and Costa Rica Wednesday night and Thursday. The arrival of long period SW swell early Thursday will help build seas even more, reaching 8 to 12 ft and locally higher offshore central America into the early parts of next weekend. Cross equatorial SW swell, with periods of 20 to 22 seconds are forecast to reach the waters between Ecuador and the Galapagos Islands Tuesday night, building seas to 7 to 8 ft by Wednesday night, shifting north of the area by late Friday. REMAINDER OF THE AREA... High pressure of 1026 mb centered N of the area near 37N139W extends a ridge across the north waters N of 20N W of 120W. The pressure gradient between this area of high pressure and the monsoon trough is supporting moderate to fresh NE winds N of 15N W of 130W. The pressure gradient between the area of high pressure and low pressure over the SW United States and NW Mexico is producing fresh to strong N winds north of 29N between 123W and 128W. Associated northerly swell propagating into the northern waters has built seas 8 to 11 ft over this area as far south as 26N between 118W and 131W. Winds over this area will decrease through tonight, with associated swell 8 ft or higher subsiding below 8 ft by early Wednesday. Fresh SW winds to the south of the monsoon trough and low pressure along the trough is helping generate 8 ft seas from 08N to 12N and west of 132W today. These seas are expected to subside below 8 ft late tonight. Cross equatorial southerly swell will spread across the waters south of 02N between 105W and 135W by Tuesday, with seas building to 8 to 10 ft. This swell 8 ft or greater will reach as far north as 13N between 90W and 130W on Wednesday. $$ GR