324 FXUS65 KVEF 130405 AFDVEFArea Forecast Discussion National Weather Service Las Vegas NV 905 PM PDT Sun Oct 12 2025
.KEY MESSAGES...
* A potent, early-season Pacific system will bring gusty winds and precipitation to the region early this week, including the first round of wintry precipitation this season. A Winter Storm Watch in effect for the Eastern Sierra Monday afternoon through early Wednesday.
* Gusty winds are expected Monday into Monday night, with a Wind Advisory in effect for the southern Great Basin, eastern Inyo County, the western Mojave Desert, and Morongo Basin.
* Well below normal temperatures are expected for much of the week, with freezing temperatures across northern and western valleys.
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.DISCUSSION...
Current water vapor imagery and 500 hPa RUC analysis indicates a deepening trough over the northwestern CONUS, and to the southeast, subtropical moisture from the remnants of Raymond continues streaming northeastward across southern Arizona and New Mexico. Between these two features, cool, dry conditions are the rule across southern Nevada, southeastern California, and northwestern Arizona, a welcome reprieve from the active weather of the past few days.
Attention turns to the next system to impact the region, with model guidance remaining in good agreement regarding the evolution of the upper pattern. The aforementioned trough will deepen and dive southward, its trajectory with its core remaining just offshore allowing for entrainment of substantial Pacific moisture. The associated IVT plume is progged to translate inland around the base of the trough, impacting the windward side of the Sierra through Monday afternoon, with this moisture expected to spill over the crest onto the eastern slopes Monday late afternoon into Monday evening. Probabilities of impactful (8-12"+) snowfall in and around Aspendell remain high (around 70-80%), with total forecast amounts through late Tuesday night/early Wednesday morning around 14-18". Thus, given snow levels around 7000 feet, the current Winter Storm Watch still looks good, with 1-2 feet of snow expected between 7000-9000 feet, and 2-3 feet expected at higher elevations across the Sierra. Snow is also expected across the White Mountains, the higher terrain of the southern Great Basin, and in the highest elevations of the Spring Mountains through Wednesday as the core of the low moves overhead and the aforementioned IVT plume is routed across the southern deserts. However, probabilities for 3-4"+ snowfall remain low in these areas (around 10-30%). Elsewhere, rain is expected across lower elevations, though flooding concerns are minimal as locations expected to see rain from this system are removed from those who saw substantial rainfall last week.
Of additional concern are gusty winds expected to overspread the region ahead of and coincident with this system, the first round of which will arrive by late Monday morning, persisting into Monday night. There are high to very high (70-90%) probabilities for locations across the southern Great Basin, eastern Inyo County, the western Mojave Desert, and Morongo Basin to see Advisory level winds, with gusts topping out around 40-50mph. These southerly to southwesterly winds will result in dangerous crosswinds on east-west oriented roadways, and will likely produce localized blowing dust.
The system driving the unsettled pattern this week will be very cold, resulting in well below normal temperatures through the upcoming week. The coolest day looks to be Wednesday, as the core of the system moves overhead, and with skies clearing across western areas early Wednesday morning, the first freeze of the season is looking increasingly likely for Bishop and locations along the Owens Valley. Ensemble probabilities for subfreezing temperatures continue increasing across the western Valleys, and thus, trends will be monitored, with a Freeze Watch likely to be issued in the next 24 hours. Stay tuned.
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.AVIATION...For Harry Reid...For the 06Z Forecast Package...Light southwesterly winds will continue through tomorrow morning when winds will start to increase from the south. By late morning/early afternoon gusty southwesterly winds will begin to impact the terminal. These gusty southwesterly winds will continue into the evening hours when wind gusts will drop off. Winds will continue to favor a southerly to southwesterly direction through the overnight period. VFR conditions prevail, with increasing mid and high clouds between 15-25kft tonight through Monday.
For the rest of southern Nevada, northwest Arizona and southeast California...For the 06Z Forecast Package...Winds across the region will favor their typical nocturnal directions with sustained speeds of 12 knots or less. With the exception of the westerly Mojave Desert where winds will favor a more westerly component, southerly to southwesterly winds will pick up across the region late tomorrow morning with gusts around 20 to 35 knots continuing into the evening hours. While these gusty westerly winds will continue through the evening hours across the western Mojave Desert, winds will decrease during the evening hours across the rest of the area with winds continuing to favor some sort of southerly direction. Cloud cover will begin to increase overnight with mid and high clouds between 15- 25kft filtering through the area through Monday.
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.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures.
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DISCUSSION...Phillipson AVIATION...Stessman
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NWS VEF Office Area Forecast Discussion