586 AXPZ20 KNHC 170404 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Sep 17 2018 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 0000 UTC surface analysis and satellite imagery through 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 09N73W to 10N86W to 11N97W to low pressure 1007 mb centered near 16N118W to beyond 11N140W. Scattered moderate isolated strong convection is within 60 nm of the coast from Nicaragua to northern Panama. Scattered moderate convection is from 08N to 19N between 100W and 123W, and from 06N to 12N west of 129W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough over the Baja Peninsula will generally maintain light to moderate winds over the Gulf of California through Tue morning. Afterwards, the winds are forecast to increase to moderate to fresh speeds in response to a high pressure ridge building to the NW. Winds over the gulf N of 29N are forecast to become strong and from the SE early on Wed continuing through Thu morning. Fresh to strong winds are then expected to develop across the central Gulf of California through Thu night. The same high pressure will generate fresh winds W of Baja California Norte Mon night through Wed morning with a swell of 8 ft. Pulses of long period SW swell will continue to impact the entrance of the Gulf of California, and the waters W of Baja California through Tue night. Moderate to fresh monsoonal flow along with a 1007 mb low centered SW of the Revillagigedo Islands near 17N118W are supporting seas to 9 ft in the offshore waters between Jalisco and the Revillagigedo Islands south of 21N. This low is forecast to continue a southwest track the next three days, thus allowing for a decrease in the winds and seas in the offshores of Baja California Sur on Mon. A new center of low pres is forecast to develop just west of the Revillagigedo Islands Mon night. The low is expected to stay nearly stationary through Tue evening, then it will start tracking NNE and reach central Baja early on Thu. There is still a high chance of this system on becoming a tropical cyclone within the next 5 days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough is expected to remain in the vicinity of 07N to 12N during the next several days. Winds will be light to gentle N of the trough and gentle to moderate S of the trough, except on Mon where moderate winds will funnel through the Gulf of Papagayo extending to the Nicaragua, El Salvador and Guatemala offshore waters. Cross-equatorial SW swell will continue to impact the coast of Central America through Tue night followed by a pulse of long period swell of 20 seconds reaching the coastal waters on Wed morning. Seas are expected to be in the 5 to 7 ft range. REMAINDER OF THE AREA... A weakening surface trough constituting the remnants of Paul, extends from 17N138W to 25N140W. The trough will continue to move west and is forecast to pass completely to the W of 140W early on Mon. High pressure will build N and E of the trough during the next few days, which will tighten the pressure gradient and cause the area of fresh winds and 8-10 ft seas near the northern trough that will extend to 135W through Wed. Otherwise, the low currently southwest of the Revillagigedo Islands near 17N118W will continue to track WSW through the next few days. The area of winds and seas associated with this low will gradually expand and combine with the area of winds and seas mentioned in the previous paragraph by Tue evening. $$ NR