Area Forecast Discussion

KEY MESSAGES

* Monsoonal moisture remains in place over the region, though daily storm coverage will tend to decrease late in the week and over the weekend.

* Warming temperatures are expected late week through the weekend, with widespread Major Heat Risk across the Mojave Desert.

DISCUSSION

through Monday.

Morning satellite imagery shows abundant mid-level and high clouds strewn across northwestern AZ and southeastern NV. This should suppress instability and limit convective coverage in these area. Instead, the bulk of activity will be focused in the southern Great Basin and western Inyo County. Flash flooding and gusty outflow winds will be the main hazards. Convective coverage is expected to decrease over the coming days as moisture decreases slightly and temps warm aloft. However, isolated activity remains possible, particularly on the fringes of the area (eastern Mohave County, southern Great Basin, and Sierra) where PoPs remain 10-30% through the weekend.

Temps are forecast to warm over the coming days, going from near- normal values to ~5 degrees above normal for late July. The highs aren't overly impressive, but the lingering moisture will make it feel relatively humid. However, the main story is the overnight lows. Thanks to moisture and periods of high clouds, forecast low temperatures are 5-10 degrees above normal. As a result, there won't really be an opportunities to get a break from the heat. HeatRisk values in the Mojave Desert climb into the Major (level 3 of 4) category with pockets of Extreme (level 4) HeatRisk. While a few lucky locations may see an isolated shower/storm to provide some daytime reprieve, the bulk of the Mojave Desert is going to see oppressive heat Thursday through Monday. The Extreme Heat Watch has been upgraded to a warning.

AVIATION...For Harry Reid...For the 00Z Forecast Package

East to southeast winds will prevail into this evening with speeds generally around 8-10 knots, but a few gusts to around 15 knots can't be ruled out. After 06z, winds are expected to shift to a southwest direction around 8 knots and remain overnight. There is a low (<10%) probability of outflow winds impacting the terminal, but if it does occur, it would likely come from the northwest. Temperatures will drop below 100F after 03Z.

For the rest of southern Nevada, northwest Arizona and southeast California...For the 00Z Forecast Package...The only TAF site that is expected to see thunderstorm influences is KBIH where scattered storms and gusty outflow winds will continue through 02Z before weakening. Overnight, probabilities are less than 10% that any TAF site will see thunderstorms or shifting outflow winds. Otherwise, typical diurnal winds with speeds less than 10 knots, except for KDAG where gusts to around 25 knots will persist overnight. FEW- SCT100 SCT-BKN150 for most areas overnight.

SPOTTER INFORMATION STATEMENT

Spotters are encouraged to report any significant weather or impacts according to standard operating procedures.