510 AXPZ20 KNHC 201551 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Jul 20 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 1500 UTC. ...TROPICAL WAVES... A tropical wave is analyzed from 06N to 16N near 104W moving W around 20 kt. The wave is diagnosed from the 700 mb tropical trough diagnostics as well as a maximum in total precipitable water weest of the trough axis. Scattered moderate convection is noted from 07N to 13N between 100W and 108W. This system has a moderate chance of developing into a tropical cyclone during the next five days. A tropical wave is analyzed from 04N to 14N near 112W moving W at 15 to 20 kt. The wave is quite weak and primarily tracked via persistence of past position and movement. Scattered moderate convection is noted from 05N to 08N between 110W and 113W. A tropical wave is analyzed from 07N to 16N near 132W moving W at 15 to 20 kt. The wave is well-defined at both 700 mb as well as the surface with the ASCAT scatterometer at 0606 UTC showing a pronounced surface trough with the wave. Scattered moderate convection from 10N to 13N between 130W and 133W. This system has only a low chance of developing into a tropical cyclone during the next five days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends across the entire basin emerging from Costa Rica near 09N83W to 09N110W to 13N125W to 13N140W. Scattered moderate and isolated strong convection is noted north of 04N and east of 86W. Scattered moderate convection is occurring within 120 nm of the trough between 86W and 108W. Scattered moderate convection is also observed within 180 nm south of the trough from 110W to 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge is in place from 32N137W to the Revillagigedo Islands maintaining winds of only fresh breeze or weaker across the Mexican offshore waters. Little change is expected for the next several days. A long-period southwesterly cross-equatorial swell is moving into the region today, allowing seas to build to 9 ft in open waters through early next week. In the Gulf of Tehuantepec, pulses of strong northerly gap winds will occur during late night and morning hours through Mon morning before fading on Tue. Wind waves from these northerly winds will interact with the SW swell event to produce mixed seas south of the Gulf up to 9 ft by Mon before fading on Tue. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong easterly winds during late night and morning hours are expected into early next week. Seas from these easterly winds will interact with the SW swell event to produce mixed seas southwest 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. Southerly winds of only fresh breeze or weaker are expected S of the trough axis the next few days. A long-period southwesterly cross-equatorial swell is moving into the region today, allowing seas to build to 9 ft in open waters through early next week. REMAINDER OF THE AREA... A surface ridge is in place from 32N137W to the Revillagigedo Islands maintaining tradewinds of only fresh breeze or weaker across the high seas. Little change is expected. See discussion above regarding the tropical wave near 104W. Large long period southwesterly swell is moving across the equator between 90W and 130W, and will continue to propagate northward, affecting most of the area east of 130W before fading on Tue. $$ Landsea