783 FXUS65 KVEF 212101 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 200 PM PDT Sat Aug 21 2021 .SYNOPSIS...Below normal temperatures continue through Sunday before warmer weather returns next week. Heat risk increases late in the week as high temperatures climb to near daily records Thursday and Friday. Monsoonal moisture increases late in the week which could bring a few thunderstorms to Mohave County heading into the weekend. && .DISCUSSION...Tonight and Sunday night. Smoke from California wildfires will continue to create air quality issues in the Owens Valley and Esmeralda County through the weekend. The rest of the area should remain relatively clear although some haziness may be seen at times. High temperatures on Sunday are expected to be around 5 degrees below normal which would mean highs topping out in the upper 90s in Las Vegas. Winds will decrease tonight with locally breezy winds on Sunday although wind speeds are expected to be lower on Sunday. Taking a peek at the tropics, Tropical Storm Grace is located near Mexico City in southern Mexico moving west and is forecast to weaken to a tropical depression. The remnants of Grace are forecast to emerge over the Eastern Pacific late Sunday night. The NHC currently has a 70 percent chance of a tropical depression forming. Monday through Wednesday...Expansive high pressure is centered over the southern plains extending westward across New Mexico and Arizona. Weak troughing is forecast over the Pacific Northwest which keeps a dry southwest flow aloft over our area. Temperatures will be on the rise but only back to around normal Monday and Tuesday before warming to above normal on Wednesday. Under the southwest flow, afternoon breezes are possible each day. Thursday through Saturday...Two things are happening later in the week. The trough over the PacNW discussed in the previous period is forecast to move east with our area on the eastern fringe of high pressure over the Eastern Pacific. This will send temperatures a few degrees higher across our area Thursday and Friday where they are forecast to plateau before trending down Saturday. High temperatures on Thu/Fri are forecast to be near records in some locations including Las Vegas. Heat risk increases in response with our southern areas seeing an increase in high risk for heat related impacts...especially on Friday. Dew points, which had been in the 20s and 30s area wide earlier in the week, are forecast to be in the mid 40s to low 50s across southern Mohave, southeastern San Bernardino counties, and the Colorado River Valley. As we head into the weekend, dewpoints increase further north but the highest surface moisture remains in the areas previously mentioned. This could signal a return of thunderstorm activity to Mohave County by Friday or Saturday. && .AVIATION...For McCarran...Gusty southerly wind of 20-30 kt will continue into the evening hours. Gusts will diminish with the loss of daytime heating by about 03-04Z but breezy conditions will remain with continued southerly wind of 10-15 kt. A calmer, more typical diurnal pattern returns overnight until southerly gusts return Sunday afternoon. For the rest of southern Nevada, northwest Arizona and southeast California...Gusty southerly wind can be expected into the evening at most terminals across the forecast area. Gusts will diminish late this evening after sunset bringing back typical diurnal winds. At KBIH, wildfire smoke will continue to be a concern bringing vis down to 3 miles and possibly lower at times overnight. Mountain obscuration will be widespread along the Sierra front. Smoke will reduce visibility through the morning hours with some improvement during the afternoon hours Sunday. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ Discussion...Salmen Aviation...Berc For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter