831 FXUS65 KVEF 070534 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 1033 PM PDT Wed May 6 2020 .SYNOPSIS...Above average temperatures expected to continue through the weekend. A weak disturbance may result in some isolated thunderstorms Sunday, but chances are very low at this point. Drying fuels and a chance of breezy to windy conditions across parts of the region early next week may result in elevated fire weather concerns. && .EVENING UPDATE... Very little change in the forecast details this evening. In the near term, the focus was on winds for the Colorado River Valley tomorrow. Latest hi-res guidance continues to indicate the elevate winds down the river channel which may warrant a Lake Wind Advisory but this looks borderline at the moment. Beyond that, above average temperatures through the weekend and the low end possibility for low or no precipitation thunderstorms across northwest Arizona Sunday. .DISCUSSION...Through Tuesday. Little changes from previous forecasts. Heat still mainly on track as ridge of high pressure remains in control. The Excessive Heat Watch still looks marginal outside of Death Valley, but still waiting for a clear trend in the temperatures to either trim it back or upgrade to a warning. Left it as-is for now. The wind forecast through tomorrow gets a little tricky. A shortwave passing by through Oregon, Idaho, and into Montana will be the straw that breaks the camel's back and sets in motion an interaction between the thermals of the higher Great Basin and lower Mojave Desert. With continued baking during the day, low- level thermal low continues to build into the Mojave Desert, at the same time surface high pressure strengthens in the Great Basin. Drainage flow from the higher terrain of the Great Basin will align to cross gradients and help push potentially stout north to northeasterly winds into Lincoln county, and also down the Colorado River valley by tomorrow morning. Everything looks sub-advisory now, but quite an interesting mesoscale and synoptic scale interaction that will likely cause a few hours of gusty winds in the morning; stronger than they would otherwise be if either the mesoscale or synoptic scale were isolated from one another. Things still look interesting for the weekend. A little bit of low and mid-level moisture seeps into the region underneath the ridge ahead of a pattern change taking shape by Sunday (aided by the low-level thermal low mentioned earlier). A deep upper-level low off the Pacific Northwest coast will start to knock the ridge down and to the east. A leading shortwave will eject over the region Sunday afternoon and evening, should should provide some forcing for ascent as well as helping to nudge lapse rates to be on the more unstable side. Indeed, forecast soundings for areas like northern Mohave county show some rather classic inverted-v profile. This would be conducive of dry thunderstorms and gusty winds Sunday afternoon and night. As the low strengthens off the coast and the area transitions to dry southwest flow, expect decreasing temperatures but increasing winds for Monday and Tuesday to start off next week. Given the potential dry lightning follow by dry gusty winds, went ahead and added some dry thunderstorms to the forecast grids to start raising some flags in advance of the weekend. && .FIRE WEATHER...Hot and dry weather expected through the end of the week. A pattern change will bring elevated fire danger over the weekend - first with a chance of dry thunderstorms Sunday and Sunday evening, followed by cooler but dry and breezy conditions for Monday and Tuesday. && .AVIATION...For McCarran...A southwesterly push will move in between 21z-00z with winds picking up to around 10 knots through sunset. Lighter southwest winds will persist for much of the overnight before a shift to the north is expected as a weak cold front passes through the valley. Confidence in timing of this shift is low and could occur as early as 09z or as late as 14z. Luckily, it doesn't look to be stronger than 10 knots once the shift does occur. Winds slowly shift to the east northeast throughout the day with speeds expected to remain at 10 knots or less. BKN high cloud cover will be prevalent for much of the period. For the rest of southern Nevada, northwest Arizona and southeast California...West to southwest winds will continue for the remainder of the afternoon at speeds around 10 knots for much of the area. A cold front will work its way southward this evening across the southern Great Basin and through the remainder of the area by mid- morning tomorrow. Winds will shift to the north behind this boundary and increase to 10-15 knots tomorrow morning across much of southern Nevada. Winds will be a tad stronger down the Co. River Valley; up to 15-20 knots gusting 25-30 knots through around 21z. BKN high clouds will be prevalent for much of the period. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Steele AVIATION...Guillet For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter