539 FXUS65 KVEF 101031 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 330 AM PDT Wed Oct 10 2018 .SYNOPSIS...Upper level disturbances dropping down from the Pacific Northwest will bring the best potential for showers to southeast Nevada and northwest Arizona late tonight and Thursday then dry conditions return for the weekend. A closed upper low will then circulate around southern California during the weekend and early next week providing some uncertainty in the weather. && .SHORT TERM...through Friday night. Minor weather concerns in the form of scattered showers will enter the picture later tonight and Thursday...primarily over southeast Nevada and northwest Arizona. Isolated showers will be possible over the rest of southern Nevada and the southern Sierra and Owens Valley. The feature that will create the showery weather was digging off the Oregon Coast this morning and will slide over central Nevada tonight and stall. Limited moisture will accompany the shortwave and some additional low level moisture advection will come up from the south 850-700 MB southerly flow enhances. The ingredients will come together best early Thursday morning through the afternoon. A few thunderstorms may occur over Mohave County, but rainfall amounts are expected to be light...generally less than a tenth of an inch. Showers will dissipate Thursday night and mostly vanish Friday as energy retrogrades off the southern California Coast and leaves our forecast area under weak split flow aloft with very little moisture and forcing. && .LONG TERM...Saturday through Tuesday. General pattern for the weekend and the beginning of next week would continue the cooler and slightly unsettled weather over the desert southwest. Still not a lot of model agreement for the weekend, with an upper low digging south of the area then strengthening. Models do seem to be trending towards some light precipitation south of I-40 Saturday afternoon. There is very little moisture available to work with, however decent lift will be overhead with a decent area of diffluence. This could be enough to squeeze out some showers, so added some slight chance precipitation chances. Some of the longer range models have light showers again on Sunday afternoon, but the better lift will have moved east by then, so left it dry on Sunday. North winds on Sunday will pick up though as the low passes to the south and the pressure gradient strengthens. Increased winds from previous Sunday per model trends. The forecast for the beginning of next week looks more uncertain as models disagree with how the upper low to our south will interact with the longwave northern trough. The GFS wants to kick the low out as it merges with the synoptic trough moving eastward and replacing it with ridging over the western US. The ECMWF never merges the two systems and therefore the low continues to sit and meander over the area. This will play a deciding role in precipitation chances, cloud cover, and temperatures for next week. With little confidence, didnt make significant changes after Sunday except to decrease high temperatures a few degrees based on long range guidance. && .AVIATION...For McCarran...Winds will be lighter today than yesterday with more of a diurnal pattern expected. Light and variable winds early this morning should briefly go east then south this afternoon. A few gusts to around 15kts possible. VFR clouds will develop this afternoon. Wind tonight will become southwest around 10kts before dropping off again after midnight. For the rest of southern Nevada, northwest Arizona and southeast California...VFR afternoon clouds will lighter winds expected today. Some gusts are possible in the Colorado River Valley to 20kts this afternoon. Winds should diminish and become diurnal overnight, except in DAG where breezy west winds will continue through the night. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter