787 FXUS65 KVEF 141923 AFDVEFArea Forecast Discussion National Weather Service Las Vegas NV 1223 PM PDT Sun Sep 14 2025
.KEY MESSAGES...
* High pressure building across the Southwest will keep conditions warm and dry through midweek.
* Increasing shower and thunderstorm activity is anticipated Thursday through the weekend, though details such as coverage and rainfall amounts remains uncertain.
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.DISCUSSION...through this weekend.
High pressure ridge will continue to build across the region through Wednesday, with dry conditions continuing as well as a warming trend over the next few days. The average last 100 degree day of the year in Las Vegas is around September 18th, and by Wednesday NBM probabilities climb to 10% for reaching 100. As moisture and cloud cover increases on Thursday, temperatures will begin to trend downward through the weekend. While temps will be above normal, heat risk remains pretty firmly in the minor territory outside of the lower reaches of Death Valley and the Colorado River Valley.
Meanwhile, Tropical Storm Mario has regenerated this morning in the Eastern Pacific and will gradually trek northwest over the next couple days before eventually dissipating. As its remnants drift northward they will become entrained in the flow thanks to a weak low lurking off the SoCal Coast, and eventually spread north into the Mojave Desert and southern Great Basin by late week. Overall, forecast guidance remains in pretty agreement on this general concept of moisture advancement into the region. What`s less certain is if there will be favorable forcing features (jet streak, shortwaves, boundaries, etc) present to act on this moisture. This makes details like precipitation coverage and amounts less certain, but for now the fairly widespread 20-50 percent PoPs late in the week and into the weekend look pretty good and are in agreement with our general messaging. Stay tuned over the coming days as we better hone in on the potential for heavier rainfall and areas of more concentrated activity.
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.AVIATION...For Harry Reid...For the 18Z Forecast Package... Wind direction will follow typical diurnal patterns through the forecast period with light, mainly variable winds this morning becoming more east to southeast during the afternoon. Winds will generally remain under 10KT, but an occasional gust to 15KT is possible during the afternoon. VFR conditions will prevail with temperatures remaining under 100 degrees.
For the rest of southern Nevada, northwest Arizona and southeast California...For the 18Z Forecast Package...Across the region, winds will generally follow typical diurnal patterns into Monday, with sustained speeds remaining around 10KT or less. Southeast to south winds at KBIH are expected to be closer to 10-12KT between 22-01Z. VFR conditions prevail areawide. &&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures.
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DISCUSSION...Outler AVIATION...Gorelow
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NWS VEF Office Area Forecast Discussion