000 AXPZ20 KNHC 211620 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1457 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 1200 UTC surface analysis and satellite imagery through 1430 UTC. ...SPECIAL FEATURES... Tropical Storm Estelle was centered at 20.1N 128.1W, or about 1030 miles W of the southern tip of the Baja California Peninsula at 1500 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 997 mb. Scattered moderate to isolated strong convection is currently noted within 120 nm over the NW semicircle. 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 13N103W, and surface pressure is estimated at 1008 mb. Numerous moderate scattered strong convection is currently observed within 420 nm over the NW quadrant and within 270 nm over the NE quadrant. Scattered moderate convection is observed over the SE semicircle within 90 nm. 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 1008 mb low pres is embedded in the monsoon trough near 10N113W. Scattered moderate isolated strong convection is currently observed within 390 nm over the W semicircle and within 210 nm over the E semicircle. 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 07N78W to low pres near 13N103W to low pres near 10N113W to 09N121W to 14N138E to beyond 14N140W. ...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 32N135W to 20N115W. The gradient on the E side 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 oriented trough will meander E and W over the Baja California Peninsula and the northern Gulf of California this week, maintaining light and variable winds across the Gulf of California waters through Fri. Gentle to moderate S flow is expected from Sat until early next week. Fresh N 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: An area of combined seas of 6-9 ft, will shift W across the discussion waters N of 07N between 94W and 106W today will subside to less than 8 ft tonight as associated SW swell continue to decay. Moderate E winds are expected across, and just downstream of the Gulf of Papagayo during the overnight hours through Sun night, then guidance calls for fresh E drainage flow to resume Mon night. W of 120W: Tropical Storm Darby has moved W of the area. An associated area of combined seas of 8-9 ft lingers on the edge of the discussion waters from 19-25N W of 137W today. See the special features above for information on tropical cyclone Estelle that will pass WNW through the central portion of the area through this upcoming weekend. A tropical low is forecasted to move into the area near 11N120W tonight accompanied by fresh to strong E winds within 300 nm N of the center. Environmental conditions continue to favor tropical cyclone development in 3 to 5 days. $$ CAM