Area Forecast Discussion

KEY MESSAGES

* After mostly dry and low impact weather today, a deepening trough will impact the region midweek with widespread rain and mountain snow chances, gusty winds, and below normal temperatures. * Increasing confidence for a dry conditions and warming temperatures this weekend.

DISCUSSION

Through the Weekend.

Today will feature near normal temperatures with abundant sunshine. Other than an isolated shower or thunderstorm in the terrain of northern Mohave County this afternoon, it will be dry through Tuesday morning. Things change quickly starting Tuesday afternoon as a deepening upper level trough approaches the region. Gusty winds will develop Tuesday afternoon in Inyo County and the southern Great Basin due to strengthen southerly flow, which will then spread across the region on Wednesday. Gusts over 40 MPH and wind impacts will be isolated with widespread 25 to 35 MPH gusts expected. Precipitation will start as early as Tuesday afternoon as increasing moisture and upper level diffluence set up over the Southern Great Basin. Widespread precipitation chances are possible at times Wednesday through much of Thursday as the upper level trough moves into south- central California. With strong forcing and anomalous moisture in place, moderate to isolated heavy rain is possible and could lead to rain impacts, especially in southeast Nevada and western Arizona where PWATs will push 250-300% of normal. There continues to be significant uncertainty in exact details as a lot will depend on how the ingredients come together- the difference between even the 25th to 75th QPF percentiles remains large. Snow amounts continue to fluctuate as well, though increasing confidence that snow levels will remain at or above 9000ft and the main concern will be the high terrain of the Sierra. Near normal temperatures on Tuesday, cooler than normal temperatures will accompany the system as it shifts through the region.

The trough should exit Thursday or Friday as it continues on to the east. Precipitation chances will end west to east as it does so as drier air filters in behind it. By this weekend, PWATs will be much lower and dry northwesterly flow should be in place- increasing confidence for a dry weekend. Temperatures will remain cooler than normal on cool northerly flow, but should warm from the temperatures associated with the peak of the rain and the system overhead.

AVIATION...For Harry Reid...For the 12Z Forecast Package

Light winds under 8KT and following daily directional patterns will continue through the forecast period. VFR conditions will continue with a few passing clouds around 10-12kft.

For the rest of southern Nevada, northwest Arizona and southeast California...For the 12Z Forecast Package...Winds will follow typical daily directional patterns and remain around 8KT or less the next 24 hours. The only exception will be KBIH in the northern Owens Valley, where southeasterly up-valley winds gusting to 15-20KT are expected to develop this afternoon. VFR conditions prevail with no operationally significant cloud cover.

SPOTTER INFORMATION STATEMENT

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