FXUS65 KVEF 190341 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 840 PM PDT Mon Aug 18 2025 .KEY MESSAGES... * Extreme Heat Warnings and Heat Advisories mid-to-late week as temperatures increase to well-above seasonal normals. * Anomalous moisture will increase precipitation potential over area mountains mid-to-late week, with chances spreading across the region over the weekend. && .DISCUSSION...Today through Monday. Today will be the coolest day of the forecast period, as a ridge of high pressure over the southern states expands westward. Through the week, this westward progression will increase heights over our forecast area, allowing afternoon high temperatures to climb to 6 to 10 degrees above seasonal normals. Due to the high confidence of this heat, went ahead and upgraded the Extreme Heat Watch over the region to Heat Advisories in the Spring Mountains, Esmeralda County, and central Nye County, and Extreme Heat Warnings elsewhere Wednesday through Saturday. The only zones without heat-related headlines include the eastern Sierra Slopes and the White Mountains in Inyo County, as temperatures will be more moderate in those higher elevations. Over the weekend, a trough will push through the western states, which will deamplify the ridge and cool temperatures across the Desert Southwest. There remains some uncertainty of the timing of this trough, with forecast high temperatures on Saturday jumping up several degrees from the previous forecast package. As such, went ahead and kept the heat headline through Saturday, as overnight lows will remain unseasonably warm (struggling to drop below 90 degrees in valley locations), and afternoon highs have the potential to over-achieve. As the aforementioned ridge of high pressure spreads westward through the work week, there will be a brief period of due southerly winds aloft late-Monday into Tuesday. This will usher monsoonal moisture up the Colorado River Valley early-to-mid week, with PWATs exceeding 1.00 inches in southern Nevada, according to the ECMWF ensemble mean. As the ridge continues to push westward, this moisture will fail to make additional northward advancement and will effectively remain stuck beneath the high. As such, PoPs increase mid-to-late week, primarily over the higher terrain, as orographic lift and daytime heating will be the main drivers for convection underneath an otherwise stable ridge. Heading into the weekend, a trough approaching the region will tap into the existing moisture, while providing a means for instability and dynamics, thereby increasing PoPs across the entire forecast area. Stay tuned to the forecast if you have outdoor plans this weekend. && .AVIATION...For Harry Reid...For the 06Z Forecast Package...Light easterly winds late this evening will turn to the typical southwest direction by midnight. Winds tomorrow will be similar to what was experienced today, with variable winds in the morning, followed by light east to southeast winds during the afternoon and early evening. Southwest winds will return after sunset. VFR conditions will prevail through tomorrow. Temperatures will top out near 106 degrees, with readings exceeding 100 degrees between 20Z and 04Z. For the rest of southern Nevada, northwestern Arizona and southeastern California...For the 06Z Forecast Package...Winds across the region will follow typical diurnal direction trends tonight and tomorrow, with speeds generally remaining less than 12 knots. The exceptions to this will be in the Owens Valley, where southerly winds with gusts to 30 knots are possible during the afternoon. VFR conditions will prevail through tomorrow across the region. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Soulat AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter