000 AXPZ20 KNHC 210950 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jul 21 2016 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 0945 UTC. ...SPECIAL FEATURES... Tropical Storm Estelle was centered at 19.8N 126.9W, or about 1115 miles w of the southern tip of the Baja California Peninsula at 0900 UTC Jul 21. Estelle is moving wnw, or 285 degrees at 13 kt. The maximum sustained winds are 50 kt with gusts to 60 kt. The estimated minimum central pressure is 996 mb. Scattered moderate to strong convection is currently noted within 150 nm over the n and within 45 nm over the s semicircles of the center. Scattered moderate convection is observed along a band well se of the center, roughly within 30 nm either side of a line from 21N123W to 18N124W to 17N126W. Estelle is forecast to track across cooler ocean waters and entrain drier air, and is expected to weaken to a remnant low over the next few days. Refer to the latest NHC forecast advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. Also see latest high seas forecast MIAHSFEP2/FZPN03 KNHC for more details on the wave forecasts associated with Tropical Storm Estelle. A surface low is embedded in the monsoon flow near 12N102W, and surface pressure is estimated at 1008 mb. Scattered moderate isolated strong convection is currently observed within 180 nm either side of a line from 09N105W to 14N102W. Fresh e winds are observed within 300 nm over the ne semicircle, with seas of 5-8 ft. The pressure gradient is expected to increase and support strong e to se winds within 240 nm ne of the low on Fri as it reaches near 15N107W. Further strengthening is likely on Sat with the low near 18N110W. This low will likely become a tropical cyclone within a day or two. ...TROPICAL WAVE AND LOWS... A tropical wave is analyzed n of 11N along 98W and has been moving w at about 10 kt. Scattered moderate isolated strong convection is noted elsewhere along the coast of Mexico within 90 nm either side of a line from 15N99W to 20N107W. Expect this tropical wave to lose identity in the increasing cyclonic circulation associated with the low pres currently near 12N102W. A 1008 mb low pres is embedded in the monsoon trough near 10N112W. Scattered moderate isolated strong convection is currently observed within 180 nm over the w semicircle, and along a band se of the low, roughly within 120 nm either side of a line from 11N107W to 06N114W to 08N118W. This low has a high potential for tropical cyclone formation in 3 to 5 days as it moves wnw to near 11N117W on Fri, and near 11.5N123W on Sat. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A monsoon trough extends wsw from the pacific coast of Colombia at 08N78W to 07N83W, then turns nw through the previously described embedded low pres at 12N102W, then the monsoon trough turns sw through the previously mentioned embedded low at 10N112W, then turns w to 11N123W where it loses identity. ...DISCUSSION... N of 15N e of 120W: See special features above for information about a surface low that will track nw across the area through the middle of next week. A surface ridge extends from 27N120W to 16N106W. The gradient ne of the ridge will support moderate nw-n winds through tonight, then fresh nw breeze is forecast across the open Pacific waters to the n of 29N on Fri and Sat, with seas gradually building to 5-8 ft. A nnw to sse orientated trough will meander e and w over the Baja California Peninsula and the northern Gulf of California this week, supporting light and variable winds across the Gulf of California waters through Fri. A gentle to moderate southerly flow is expected to begin on Sat, and will persist into early next week. Fresh northerly flow will persist through sunrise this morning across, and just downstream of the Gulf of Tehuantepec. Fresh to locally strong n flow is expected again tonight with seas building briefly to 8 ft. S of 15N e of 120W: See section on tropical wave and low for information on a tropical wave currently along 98W, and a surface low near 10N112W. An large area of combined seas of 6-9 ft, will shift w across the discussion waters n of 05N w of 90W today while gradually subsiding to less than 8 ft tonight. Moderate e winds are expected across, and just downstream of the Gulf of Papagayo during the overnight hours through Sun night, then guidance is hinting at fresh e drainage flow resuming on Mon night. W of 120W: Tropical Storm Darby has moved w of the area with an associated area of strong e winds and combined seas of 8-11 ft continuing across the discussion waters from 18-26N w of 137W today. See special features above for information on tropical cyclone Estelle that will pass wnw through the central portion of the area through this upcoming weekend. Combined seas of 6-9 ft primarily due to mixing swell, are expected to surround the large seas near the cyclone, and cover the waters elsewhere to the n of 07N through the weekend. A tropical low is expected to move into the area near 11N120W tonight accompanied by fresh to strong e winds within 300 nm n of the center. Environmental conditions will favor tropical cyclone development in 3 to 5 days. $$ Nelson