387 FXUS65 KVEF 200346 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 846 PM PDT Tue Oct 19 2021 .SYNOPSIS...Cooler than normal temperatures are expected through Thursday before returning to near normal Friday and Saturday with occasional passing high clouds. A Pacific System will bring significant precipitation to the southern Sierra late this weekend and potential wet weather to much of our region early next week. && .UPDATE...Quiet weather across the region this evening. Surface winds are generally light except for gusty winds to around 25 mph being reported at the Bishop CA airport in the northern end of the Owens Valley. High clouds are moving in from the west and are forecast to reach Clark County by daybreak. Temperatures overall are a little warmer this evening than last with the exception of the Colorado River Valley where temps were a touch cooler. && .PREVIOUSLY ISSUED DISCUSSION... .SHORT TERM...through Friday night. Dry and mild conditions will continue across most of the region with temperatures climbing a few degrees each day as they gradually return to near normal by Friday. The exception will be the southern Sierra which stands a 20-30 percent chance of some light precipitation by Friday afternoon as a weak shortwave moves inland from the Pacific and brushes the Sierra. This will also stir up south-southwest winds generally 10-20 across the region. Occasional waves of dense cirrus will skirt the region under a mean southwest flow aloft. .LONG TERM...Saturday through Monday. Saturday will remain dry with considerable clouds across our region under a westerly flow aloft as a potent Pacific System is forecast to direct an atmospheric river into northern and central California. Model ensembles indicate this AR will likely begin to spread over the southern Sierra and nearby central Nevada Sunday afternoon and Sunday night then the tail end of it is forecast to transition across southern California/Nevada and northwest Arizona on Monday. For our forecast area, the west facing slopes of the southern Sierra will likely intercept the majority of the precipitation, but there should be plenty of precip spilling over onto the east slopes and Owens Valley...likely over 1" of rainfall. Snow levels should generally remain above 9000 feet through most of the event leading to potential heavy snow confined to the high peaks. Confidence in the details is not high this far out, but it appears precipitation will fall mostly as rain below 8000 feet and there may only be a few inches of snow near Aspendell. The Mojave Desert region should see only light amounts of rainfall, as the base of the incoming broad trough swings inland and eventually cuts off the moisture tap by Monday evening. && .AVIATION...For McCarran...Light winds generally less than 7 knots will continue tonight and Wednesday with light easterly components in the afternoon hours and southwest components overnight. Clouds above 20 kft will increase late tonight through Wednesday morning. For the rest of southern Nevada, northwest Arizona, and southeast California...No significant weather is expected across the region through Wednesday. Winds will remain generally less than 12 knots with increasing clouds above 20 kft tonight through Wednesday morning. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Salmen DISCUSSION/AVIATION...Adair For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter