FXUS65 KVEF 191149 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 449 AM PDT Tue Aug 19 2025 .KEY MESSAGES... * Hotter than normal temperatures are on tap for the region this week with Extreme Heat Warnings and Heat Advisories in effect Wednesday through Saturday. * Moisture will return to the region during the second half of the week, bringing increased precipitation chances to the area. && .DISCUSSION...through next Tuesday. Temperatures will continue to increase each day through the end of the week as we find ourselves under higher than normal 500 mb heights courtesy of the Four-Corners High. Afternoon high temperatures will top out around 5 degrees above normal as temperatures peak on Thursday and Friday. While 5 degrees above normal might not sound too bad, there will be little overnight relief with this heatwave as overnight low temperatures will be around 6 to 12 degrees above normal each night during the second half of the week. This combination of hotter than normal temperature during the day and anomalous overnight temperatures will result in widespread Moderate (Level 2 of 4) to Major (Level 3 of 4) HeatRisk with pockets of Extreme (Level 4 of 4) HeatRisk during the second half of the week. As such, A Heat Advisory is in effect for Esmeralda County, central Nye County, the Spring Mountains, and the Sheep Range from 8:00 am Wednesday through 11:00 pm Saturday. An Extreme Heat Warning is in effect for the Owens Valley, Death Valley, San Bernardino County, Mohave County, Lincoln County, and Clark County from 8:00 am Wednesday through 11:00 pm Saturday. While the heat headlines run through Saturday, one potential caveat is that convective cloud cover and precipitation could limit afternoon temperatures for portions of the region. As the high pressure ridge settles over the Four Corners Region, we will find ourselves in our typical monsoonal pattern with southeasterly flow aloft helping to transport moisture into our area. Moisture will begin to increase today, but the only evidence of this moisture will be increased cloud cover for portions of the region. Precipitation chances will begin to increase in the eastern portions of Mohave County on Wednesday afternoon, slowly pushing further west on Thursday afternoon as moisture continues to increase. Chances for afternoon showers and thunderstorms will become more widespread across northwestern Arizona, southern Nevada, and southeastern California beginning Friday and continuing into the weekend. Lightning, gusty outflow winds, and localized heavy downpours will be threats with any convection that develops. Forecast confidence decreases as we head into next week due to discrepancies regarding a potential trough and the return of dry southwesterly flow. The timing of this shift to drier flow aloft will determine how long we will see moisture linger across the region as it recirculates beneath the ridge. && .AVIATION...For Harry Reid...For the 12Z Forecast Package...Mainly diurnal winds are expected through Wednesday morning, with light southwesterly winds this morning gradually veering around to the southeast through this afternoon. Late afternoon, a brief period of intermittently gusty south-southwesterly winds is expected with gusts to around 15-18KT possible before winds diminish after sunset. VFR conditions prevail with bands of passing mid- and high clouds through the period. Temperatures will exceed 100F between 20Z-04Z, topping out at 106F around 00Z. For the rest of southern Nevada, northwest Arizona and southeast California...For the 12Z Forecast Package...Winds will follow typical diurnal patterns across the region through the forecast period. Speeds will be around 10KT or less, with a few exceptions. Across the western Mojave Desert, winds largely remain west- southwesterly, with gusts to 20-25KT expected late evening through much of the night. In the Owens Valley, gusty up-valley winds are expected to develop by this afternoon, with gusts to 25-30KT thereafter through early evening. Any gusts elsewhere will be intermittent during peak heating, generally up to around 15KT at most, particularly across portions of the Colorado River Valley. VFR conditions will prevail, with passing mid and high clouds with bases 12kft or above. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Stessman AVIATION...Phillipson For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter