939 AXPZ20 KNHC 161525 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1413 UTC Sun Sep 16 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 1200 UTC surface analysis and satellite imagery through 1415 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 10N73W to 09N82W to low pressure 1007 mb centered near 18N116W to 11N130W to beyond 11N140W. Scattered moderate isolated strong convection is present within 60 nm either side of a line from 06N80W to 08N93W to 12N100W and from 10N to 21N between 100W and 118W. Scattered moderate convection is seen from 08N to 09N between 128W and 135W. ...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. During the second half of the week winds are forecast to increase to moderate to fresh speeds over the Gulf in response to a high pressure ridge building to the NW. Winds over the Gulf of California N of 29.5N could become strong from the SE on Wed. This same ridge of high pressure will generate fresh to strong winds W of California, which will generate NW swell. These swell will cause seas to build to above 8 ft N of 26N E of 130W Tue night through Thu night. Gentle to moderate NW flow will prevail across the offshore waters W of Baja California through Tue night. Seas will generally range between 5 and 7 ft. Expect moderate to fresh NW winds, and seas of 6 to 8 ft N of Punta Eugenia Wed as the pressure gradient tightens with a ridge building in from the NW. Additional pulses of long period S swell will continue to impact the entrance of the Gulf of California, and the waters W of Baja California through Wed. Moderate to fresh monsoonal flow along with a 1007 mb low centered west of the Revillagigedo Islands near 18N116W are supporting seas to 8 ft in the offshore waters S of 21N. This low is forecast to drift west of the Baja California Sur offshore waters today, thus allowing for a decrease in the winds and seas. Another low pres is forecast to develop just west of the Revillagigedo Islands early on Mon. The low is expected to be nearly stationary through Tue evening, then will start tracking NNE toward central Baja by Fri. This system has a high chance of becoming a tropical cyclone during 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 10N to 12N during the next several days. Winds will be gentle to moderate N of the trough and moderate to fresh S of the trough as a large area of disturbed weather prevails. Cross-equatorial SW swell are decaying but will continue to impact the coast of Central America through Wed. Seas of 8 to 9 ft are affecting the waters between Ecuador and the Galapagos Islands, and also reach to near the Azuero Peninsula. These marine conditions are forecast to subside tonight and Mon. The next round of SW swell is not expected until at least the end of next week. REMAINDER OF THE AREA... A weakening surface trough constituting the remnants of Paul, extends from 16N136W to 26N138W. The trough will continue to move west and is forecast to pass to the W of 140W by midday Mon. High pressure will build N and E of the trough during the next few days, which will tighten the pressure gradient and cause an area of fresh to strong winds from 13N to 22N west of 125W by Tue evening. Seas in this area will ranging between 8 and 9 ft. Otherwise, the low currently west of the Revillagigedo Islands near 18N116W will continue to track WSW through the end of next week. The area of winds and seas associated with this low will combine with the area of winds and seas mentioned in the previous paragraph by Tue evening. $$ CAM