691 FXUS65 KVEF 230846 AFDVEFArea Forecast Discussion National Weather Service Las Vegas NV 146 AM PDT Tue Sep 23 2025
.KEY MESSAGES...
* Low impact weather with dry conditions and near normal temperatures likely through Wednesday.
* Precipitation chances increase the second half of the week as anomalous moisture interacts with an upper level disturbance, however details and weather impacts remain low confidence at this time.
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.DISCUSSION... Weak ridging is expected to build over the region today and Wednesday. Under mostly sunny skies, temperatures will sit near normal for this time of the year. Breezy north winds will develop each afternoon but no impacts are expected as gusts remain under 25 MPH.
An unsettled weather pattern is expected to set up after Wednesday as an upper level low off the California Coast shift east into the Desert Southwest. Meanwhile, PWATs will increase, climbing to 150%- 200% of normal Thursday onward (though it`s worth mentioning: PWAT normals are starting to decrease as we exit our typical monsoon season). None the less- with anomalous moisture and increasing forcing, chances for precipitation are expected at times Thursday through at least the weekend. Details beyond that are uncertain though as models show differing solutions with how the upper level system moves through the region. Cluster analysis all generally show the disturbance moving inland on Thursday then moving overhead Friday and Saturday, center over southern Nevada-ish, before shifting into Arizona on Sunday. Precipitation chances, coverage, amounts, and potential impacts will depend on the exact track and strength of the low. NBM 50th percentile 24-hr rainfall amounts are not overly impactful, however there is a large spread between the 50th and 90th percentile and some 90th percentile 24-hr rainfall amounts suggest at least minor rainfall impacts. The Weather Prediction Center paints the Southern Great Basin and northern Mohave County with a Marginal Excessive Rainfall Risk on Thursday, then expands the Marginal Risk across the entire region for Friday and Saturday. At the moment, this is a fair assessment as any rainfall that develops could be heavy at times given the anomalous moisture and upper level support which could lead to localized flash flooding in flash flood prone areas. Expect fine tuning of impacts and forecast details as we get closer to later in the week, stay tuned.
After Saturday, models consensus diverges even further with what the upper level disturbance does as it moves into Arizona. Ensembles do show PWATs remaining above normal through early next week though- so the continued presence of moisture should keep rain chances in the forecast, especially in the afternoons with any diurnal heating. Temperatures after Wednesday will cool with high temperatures dropping to below normal levels Thursday through early next week.
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.AVIATION...For Harry Reid...For the 06Z Forecast Package...Light southwest winds this evening, remaining light overnight before shifting to the northeast by mid to late morning Tuesday. Wind speeds will increase to around 10-12KT, persisting through sunset. Intermittent gusts to around 15KT can be expected, though timing remains uncertain. Otherwise, VFR conditions prevail, with clearing skies through tonight.
For the rest of southern Nevada, northwest Arizona and southeast California...For the 06Z Forecast Package...Winds through tonight will generally follow typical diurnal directional patterns, with wind speeds around 8KT or less. Tuesday mid to late morning, winds shift to the north and northeast across southern Nevada, northwestern Arizona, and across the Colorado River Valley, with wind speeds increasing to around 10-12KT, and stronger through the Colorado River Valley due to topographic effects. Gusts there could reach 20-25KT before winds diminish late in the forecast period. Across the western Mojave Desert and Owens Valley, gusty diurnal winds are expected, with easterly gusts to 20-25KT and southerly up- valley gusts to around 20KT, respectively. Otherwise, VFR conditions will prevail.
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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... AVIATION...Gorelow
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NWS VEF Office Area Forecast Discussion