Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
087 FXUS65 KVEF 170900 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 200 AM PDT Wed Jul 17 2024 .SYNOPSIS...Heat will be the primary weather story through the weekend as a large high pressure center moves overhead. Isolated thunderstorm activity will remain a possibility as well, mainly in Northwest Arizona today, but spreading into the eastern Mojave Desert Thursday onward. Temperatures will soar to excessive heat levels over the weekend. Greater storm chances are suggested early next week as a deeper push of moisture arrives in the area. && .SHORT TERM...through Thursday. High pressure center currently settled across western New Mexico will expand westward over the coming days with a slightly strengthening southerly steering flow developing over the region. This will ensure hot temperatures continue, as 594dm heights spread further west. Unlike a couple weeks ago, this high pressure center is no longer extremely dry and instead has fairly considerable moisture trapped beneath it. This is resulting in elevated surface dew points generally in the 40s and low 50s across the region. This will add a little more kick to the heat via a slightly higher apparent temperature, and limit nocturnal cooling potential to some degree. The elevated atmospheric moisture will also promote continued thunderstorm activity, mainly across northwest Arizona today but perhaps spreading into eastern San Bernardino county and southern Nevada tomorrow afternoon. .LONG TERM...Friday through Wednesday. High pressure migrates west Friday and becomes centered over Nevada over the weekend, maintaining above average high temperatures across the area. Major (Level 3) to Extreme (Level 4) HeatRisk returns to much of the forecast area including Las Vegas through the weekend and despite concerns about cloud cover and precipitation influences, went ahead with an Excessive Heat Watch given the intensity of the high that will be parked overhead. Beyond Sunday, there are indications of deeper moisture attempting to encroach on the area leading to larger uncertainty in how long the heat will last. Additionally, Low pressure over the Pacific Northwest and a trough over the Midwest may influence the position and intensity of the ridge, adding to the uncertainty. PWATs over 100 percent of normal will remain in place under the ridge and there will be daily afternoon and evening thunderstorm chances into early next week in the central and eastern sections of the forecast area where instability is the greatest. Stable air over the western sections of the forecast area (Inyo and western San Bernardino Counties) reduces the likelihood of storm activity in those areas. Moisture and cloud cover may also help mitigate the heat going into next week. && .AVIATION...For Harry Reid...Winds will primarily follow a diurnal pattern, with light and variable winds this morning becoming to southerly in the mid to late afternoon. Winds will be less than 10 kts. There is a low (20-30%) probability of thunderstorms on the Spring Mountains, Sheep Range, or McCullough Range producing an outflow boundary which impacts winds at the terminal in the late afternoon or evening hours. For Thursday, thunderstorms increase and will not be limited to the higher terrain. There will be a risk of outflow winds from thunderstorms, but otherwise diurnal winds should prevail. For the rest of southern Nevada, northwest Arizona and southeast California...Thunderstorm chances will increase marginally over Clark and Mohave Counties today and will favor eastern Mohave County, with an increased the risk of outflow winds being pushed farther to the west and into KIFP and KEED during the late afternoon and evening hours. Away from thunderstorms, expect VFR conditions with winds near or below 20 knots. Thunderstorm chances will increase areawide on Thursday. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Outler LONG TERM...Meltzer AVIATION...Czyzyk For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter