342 FXUS65 KVEF 191117 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 417 AM PDT Thu Jun 19 2025 .KEY MESSAGES... * Extreme Heat Warning remains in effect today with triple digit highs and warm overnight low temperatures. * Increasing winds are expected through Saturday. Dangerous fire weather conditions are expected today through Saturday as gusty winds and afternoon humidities in the single digits develop each afternoon. Impactful wind gusts are possible, mainly in the Western Mojave Desert Friday and Saturday. Winds diminish on Sunday and remain lower into early next week. * Temperatures will cool off Friday into early next week, bringing some relief from the extreme heat. && .DISCUSSION...Today through Next Thursday. Another hot day is expected today as high pressure remains in place over the region. Temperatures may be a 2-3 degrees cooler today compared to yesterday as the ridge begins to break down in response to an incoming trough, however high temperatures will still climb 5- 8 degrees above normal. Moderate to Major Heat Risk is forecasted today for much of the area, with the highest heat risk in desert valleys where an Extreme Heat Warning remains in effect today. The upper level trough will drop into the region, increasing the pressure gradient and thus increasing the winds. With no precipitation and afternoon humidities dropping into the single digits each day combined with these winds- prolonged dangerous fire conditions and increased fire spread potential will develop. Please see the FIRE WEATHER section for information on the critical fire weather conditions. Breezy southwest winds will develop each afternoon with widespread gust of 25 to 35 MPH. The highest risk for impactful wind gusts will be in the Western Mojave Desert Friday and Saturday when there is a 70%+ chance for gusts over 40 MPH. Winds will diminish on Sunday as the upper level trough shifts overhead. As the upper trough settles into the Southwest US this weekend, falling heights will yield a stretch of below normal temperatures for late June. As opposed to our normal low 100s, ensemble analysis points to highs in the 90s Sunday and Monday, perhaps even into Tuesday. The result will be a rather pleasant start to the last week of June by our summer standards. Winds will also decrease as the upper level low sets up over the region with the probability for impactful winds dropping to 20% or less by Sunday. && .FIRE WEATHER...Breezy south to southwest winds and very dry conditions are expected today and Friday. HREF shows high probabilities (80% or more) for relative humidities below 15% and wind speeds over 20 mph across southern Nevada and western Arizona today and Friday and a Red Flag Warning is in effect for these areas. Winds will be lighter on Friday than today in NV460 and thus Red Flag conditions are not expected, though continued dry conditions are expected as relative humidities Friday afternoon will drop below 10% again. Continued critical fire weather conditions are expected on Saturday for parts of the region as south winds will again be 10-20 MPH and relative humidities drop to the single digits, however its uncertain how strong winds will be. The highest risk for continued Red Flag conditions on Saturday will be in Mohave County where probabilities for wind speeds over 20 MPH are 80% or higher. With uncertainty in the wind forecast and where the highest risk for critical fire weather conditions, did not make changes to extend the Red Flag into Saturday yet. && .AVIATION...For Harry Reid...For the 12Z Forecast Package...Winds will favor a southerly-to-southwesterly direction through the TAF period, with 20 to 30 knot wind gusts picking up later this morning. These gusty winds will continue through the afternoon and into the evening hours. High temperatures today will top out around 108 degrees with temperatures over 100 from 18Z to 04Z. For the rest of southern Nevada, northwest Arizona and southeast California...For the 12Z Forecast Package... VFR conditions will persist through the TAF period. Gusty southerly-to-southwesterly winds will pick up across the region late this morning, continuing through the afternoon and into the evening hours. Wind gusts will be in the 20 to 30 knot range. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION/FIRE WEATHER...Nickerson AVIATION...Stessman For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter