800 FXUS65 KVEF 011109 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 409 AM PDT Fri Aug 1 2025 .KEY MESSAGES... * Mostly dry conditions and seasonal temperatures continue through the weekend and into the start of next week. * Potential for a monsoonal moisture surge midweek, with above- normal temperatures mid-to-late week. && .DISCUSSION...Today through Friday. Conditions remain largely dry across the forecast area, with the persistent, dry southwesterly flow aloft. The forecast monsoonal moisture push across Arizona has diminished considerably from forecast runs several days ago, though the ECMWF and GFS ensemble means continue to show 0.50 to 0.75" of PWAT climb up the Colorado River Valley today. This moisture will elevate afternoon relative humidities into the teens, but will struggle to produce much in the way of cloud cover or precipitation. Similarly, latest NBM runs show negligible (sub-10%) PoPs across eastern Mohave County, though cannot completely rule out an isolated shower or thunderstorm formed off of outflow boundaries from central Arizona. Conditions continue to dry out through the weekend, with sunny skies and seasonal temperatures expected heading into the next work week. There is continued inter-model agreement in a trough pushing into the Pacific Northwest / Northern California Monday and Tuesday, while the monsoonal ridge over the southern CONUS / northern Mexico continues to build. By midweek, this trough will have deamplified the ridge over the Desert Southwest, shifting the center of the high further east. This will allow moisture to once again creep up the Colorado River Valley, with forecast ECMWF ensemble PWATs peaking on Wednesday from Laughlin / Bullhead City to Las Vegas to 0.75 to 1.00". The NBM is not currently on board with this solution, as NBM forecast temperatures continue to climb above- normal mid-to-late week and NBM PoPs remain slight (10-20%) - isolated to eastern Mohave County. Regardless, all models agree that the monsoonal high will once again retrograde westward, resulting in climbing heights and increasing temperatures. HeatRisk in southern Mohave County increases to "Major" and "Extreme" Thursday and Friday. Will continue to assess the magnitude of the moisture resurgence midweek and the need for heat-related headlines late-week as we move through the weekend. && .AVIATION...For Harry Reid...For the 12Z Forecast Package...Breezy south winds continue through the period, strongest in the afternoon and evening hours. Light and variable or southeasterly winds likely during the morning hours after sunrise, but speeds expected to remain below 10 knots until south-southwest gusts of 20-25 knots arrive in the afternoon. Winds weaken again after sunset. Temperatures exceeding 100F between 20z and 03z, with a high around 106F under clear skies. For the rest of southern Nevada, northwestern Arizona and southeastern California...For the 12Z Forecast Package...Light winds this morning give way to southerly/westerly breezes across the region this afternoon. Gusts generally 15-25 knots. Winds subside after sunset except in the KDAG area where they`ll remain elevated into the night. VFR conditions and mostly clear skies, with just a few shallow cumulus over northern Inyo, Esmeralda, and northern Mohave counties. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Soulat AVIATION...Woods For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter