319 AXPZ20 KNHC 200901 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 616 UTC Mon Aug 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...TROPICAL WAVES... A tropical wave has an axis from 06N92W to 20N90W, moving W between 20 and 25 kt. Scattered moderate and isolated strong convection is noted from 05N to 08N between 88W and 92W. A tropical wave has an axis from 04N113W to 17N112W, moving W around 15 kt. Scattered moderate convection is seen from 06N to 08N between 108W and 116W. A tropical wave has an axis from 04N131W to 16N129W, moving W around 15 kt. Scattered moderate and isolated strong convection is found within 90 nm either side of a line from 17N122W to 13N130W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pres 1010 mb near 09N74W to 08N78W to 09N92W to 11N120W. The ITCZ extends from 09N133W to 09N136W to beyond 10N140W. Scattered moderate and isolated strong convection is present from 07N to 09N between 95W and 100W. Scattered moderate convection is observed from 09N to 12N between 118W and 121W and from 07N to 11N W of 137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface ridging enters the forecast waters near 32N132W, then extends SE to near the Revillagigedo Islands. This feature will support gentle to moderate NW winds through Tue. The ridge will weaken slightly during the middle of the week as passing low pres weakens the N side of the ridge. This will allow winds to slacken a bit to between light and gentle late Tue and Wed. The ridge will then rebuild Thu, bringing a slight increase to the winds once again Thu and Fri. Surface troughing over the Baja Peninsula will maintain a light wind regime over the Gulf of California through Fri night. Strong N to NE gap winds will affect the Gulf of Tehuantepec Tue through Thu night. This event is forecasted to peak Wed night, when winds could reach 30 kt and seas could build to 10 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will linger near 09N during the next few days. Winds on both sides of the trough axis will generally be light to moderate. The main exception to this will be over the Gulf of Papagayo, where winds will pulse to fresh and become locally strong each night. Winds will peak tonight, when strong winds are expected to affect the area from 10.5N to 11.5N E of 88W. Seas are expected to remain below 8 ft. REMAINDER OF THE AREA... Hurricane Lane continues moving farther away into the Central Pacific. The area of seas above 8 ft generated by mixed swell in the vicinity of Lane moved to the W of 140W earlier this morning. Elsewhere, the pressure gradient between ridging across the northern waters and the ITCZ will support gentle to moderate trades and 4-7 ft seas in mixed swell N of the ITCZ and W of 120W through the middle of this week. Sea heights will be relatively low for most of the forecast area this week. Mixed SE and SW swell will cause seas S of 02S and W of 112W to briefly build to 8 ft later this morning through Tue morning. A much more robust round of long period swell could arrive from the Southern Hemisphere toward the end of this week and cause seas near the Equator to begin building on Sat. $$ CAM