627 AXPZ20 KNHC 152105 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1836 UTC Sat Sep 15 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 1800 UTC surface analysis and satellite imagery through 2015 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 1010 mb low pressure centered over northern Colombia near 10N75W to 11N96W to low pressure 1008 mb centered near 18N113.5W to 10N129W to beyond 12N140W. Scattered moderate and isolated strong convection associated with these features is present from 05N to 11N E of 95W, within an area bounded by 17N99W to 10N99W to 08N111W to 19N117W to 20N107W to 17N99W. A smaller area of convection associated with the western portion of the trough is found within 90 nm either side of a line from 07N122W to 13N140W. ...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 night. 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. 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 27N between 121W and 131W during the day on Thu. Gentle to moderate NW flow will prevail across the offshore waters W of Baja California, with seas generally in the 5 to 7 ft range. Expect moderate to fresh NW winds, and seas of 6 to 8 ft N of Punta Eugenia through Sun 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. Trade winds funneling between the monsoon trough and the Sierra Madre supporting seas to 8 ft in the offshore waters between 101W and 106W. This low is forecast to drift slowly west of the Baja California Sur offshore waters Sun, thus allowing for a decrease in the winds and seas. The low is expected to pass near the Revillagigedo Islands Tue and gradually develop as it tracks NW then N toward central Baja by Fri. This system retains 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 will wander in the vicinity of 10N 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 to the W helps maintain monsoonal flow during the next few days. Cross-equatorial SW swell are decaying but will continue to impact the coast of Central America through Wed. Seas of 8 to 10 ft are affecting the waters between Ecuador and the Galapagos Islands, and also reach to near the Azuero Peninsula. These marine conditions will persist today, but subside Sun 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 17N133W to 26N135W. The trough will continue to weaken and move westward and is forecast to pass to the west of the area Mon. High pressure will build north of the trough on Sun, which will slightly tighten the pressure gradient. This will result on fresh to strong winds from 22N to 24N between 135W and 139W with seas to 8 ft on Sun evening. Otherwise, an area of moderate to fresh trades will develop N of the monsoon trough and W of 125W during the second half of next week as high pressure to the N builds. Seas between the monsoon trough and 20N to the W of 130W could build to between 8 and 9 ft during this time frame. $$ CAM