523 FXUS65 KVEF 110309 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 152 PM 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. && .UPDATE...Based on current radar trends, rain chances were decreased to slight or near nil across the northern tier of the forecast area as well as Mohave County through 11 PM. Showers are expected to increase during the early morning hours Thursday as a trough axis pushes eastward across the Mojave Desert. Otherwise, the forecast is on track. -Boothe && .PREV DISCUSSION... 152 PM PDT Wed Oct 10 2018 .SHORT TERM...through Saturday morning. A shortwave trough moves into north-central Nevada today, resulting in a chance for scattered showers tonight and through much of Thursday across northwest Arizona and southeast Nevada. The best chances for rainfall will begin around midnight and continue through mid-morning Thursday, predominantly in northeast Mohave County. Widespread forecast rainfall amounts across Lincoln and east Clark counties do not exceed a tenth of an inch. Locally higher amounts are possible in northern Mohave County. Two areas of low pressure aloft will move into our region Friday, resulting in a split flow. This will keep us dry and cool through the rest of the work week and into the weekend, with high temperatures remaining in the mid-70s. .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...Generally light winds through the remainder of the afternoon with sct clouds around 10k feet along with some high level clouds. A few clouds will likely remain overnight around 10-12k feet and winds are expected to become more southwesterly after 03z with speeds around 7 kts. Winds are forecast to be light again Thursday with speeds around 6 kts occasionally out of the northeast to east direction. For the rest of southern Nevada, northwest Arizona and southeast California...Other than westerly winds over western San Bernardino County, winds are expected to remain under 10 kts through Thursday. FEW-SCT clouds around 10-12k feet. Winds again on Thursday are expected to remain less than 10 kts over most areas with just a few clouds around 10-12k feet. && .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