000 AXPZ20 KNHC 030903 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 617 UTC Tue Oct 3 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Low pressure of 1004 mb is located south of the Gulf of Tehuantepec near 13.5N95W. Numerous moderate and scattered strong convection was noted within 90 nm west semicircle of the low center. Scattered moderate isolated strong convection was noted elsewhere from 12N to 17N between 91W and 101W. Environmental conditions are expected to be conducive for some additional development over the next couple of days while the system moves slowly westward. The latest Tropical Weather Outlook gives this low pressure a medium chance of formation through 48 hours. Please refer to the latest Tropical Weather Outlook for more information on the potential for development of this low. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 14N92W to 1004 mb low pres near 13.5N95W to 12N110W to 13N117W to 1010 mb low pres near 13N127W to beyond 11N140W. Scattered moderate isolated strong convection was noted from 06N to 10N between 82W and 87W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features above for more details on low pressure south of the Gulf of Tehuantepec. 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 14N between 90W and 130W late on Wednesday. This swell will reach the offshore waters of Mexico, south of Cabo Corrientes late Wednesday into Thursday. 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, will subside to 7-8 ft today. 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 clusters of moderate to strong 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 into Thursday. The arrival of long period SW swell early Thursday will help build seas to 8 to 12 ft offshore central America the remainder of the work-week. Cross equatorial SW swell, with periods of 20 to 22 seconds are forecast to reach the waters between Ecuador and the Galapagos Islands tonight, building seas to 7 to 8 ft by Wednesday night. REMAINDER OF THE AREA... High pressure of 1023 mb centered N of the area near 35N139W extends a ridge southeast to near 22N120W. 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. Northerly swell propagating into the northern waters has built seas 8 to 11 ft over this area as far south as 24N between 118W and 131W. Seas associated to this swell are forecast to subside below 8 ft by early Wednesday. Cross equatorial southerly swell will spread across the waters south of 02N between 105W and 135W today, with seas building to 8 to 10 ft. This swell will reach as far north as 15N between 88W and 130W by late Wednesday. $$ AL