408 AXPZ20 KNHC 210916 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 715 UTC Sat Jul 21 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 the 0600Z surface analysis and satellite imagery through 0815Z. ...TROPICAL WAVES... A tropical wave is analyzed from 05N82W to 22N81W. The wave is evident in the 700 mb tropical trough diagnostics as well as a maximum in total precipitable water. Scattered moderate and isolated strong convection is noted within 60 nm of a line from 10N84W to 06N88W. A tropical wave is analyzed from 06N111W to 17N109W. The wave is collocated with weak troughing in the 700 mb tropical trough diagnostics as well as a maximum in total precipitable water satellite imagery. Scattered moderate and isolated strong convection is present from 07N to 16N between 106W and 116W. A tropical wave is analyzed from 04N120W to 16N119W. The wave is weak, but can be tracked via the 700 mb tropical trough diagnostics. Scattered moderate and isolated strong convection is seen from 07N to 12N between 116W and 121W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N73W to 11N86W to 08N104W to 09N115W to 09N122W to 12N124W to 1008 mb low pressure centered near 13N133W. Scattered moderate and isolated strong convection is noted from 07N to 14N between 95W and 106W and within 120 nm of a line from 11N130W to 09N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends SE from 32N138W to 24N131W to E of the Revillagigedo Islands near 18N107W. The ridge is maintaining light to moderate NW winds across the Mexican offshore waters. Little change is expected in these conditions during the next several days. A long period SW cross-equatorial swell is entering the waters S of 15N. The extensive swell event will continue spreading N and will cause seas to build to between 8 and 9 ft in the open waters for all the forecast zones through early next week. In the Gulf of Tehuantepec, pulses of strong N gap winds will occur during the late night and morning hours until Mon morning. Wind waves generated by these N winds will interact with the SW swell event to produce mixed seas south of the Gulf peaking near 10 ft on Sun before winds subside on Mon morning. Seas near the Gulf of Tehuantepec will remain above 8 ft until Wed morning as SW swell continue to arrive. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong easterly winds will pulse during the late night and morning hours through early next week. Seas from these easterly winds will interact with the SW swell event to produce mixed seas SW of the Gulf up to 10 ft by Mon before fading on Tue. Easterly winds of only fresh breeze or weaker are forecast elsewhere N of the monsoon trough which will meander west of Central America between 07N and 10N. Moderate to fresh S to SW winds are generally expected S of the trough axis during the next several days. A long-period SW cross-equatorial swell event is already affecting the region as seas S of the equator have risen to 8 ft. Seas will peak between 8 and 10 ft on Mon in the open waters, with the highest seas expected W of Ecuador. REMAINDER OF THE AREA... A surface ridge is in place from 32N138W to E of the Revillagigedo Islands near 18N107W is maintaining moderate trade winds N of the monsoon trough, S of 18N and W of 115W. Little change in this pattern is expected for the next several days. See discussion above regarding the tropical wave near 108W. Large long period SW swell is crossing the equator into all of the discussion area. Satellite-derived sea height data indicate seas have risen above 8 ft as far N as 11N between 100W and 120W. The swell will continue to propagate N and bring seas of 8 ft or above to most of the area east of 130W before the swell decay and seas subside on Tue. $$ CAM