937 FXUS65 KBYZ 151526 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 926 AM MDT Tue Sep 15 2020 .UPDATE... Strong high pressure aloft will keep our weather quiet and warm today, with temps a bit cooler than Monday. Nighttime RH recoveries were quite poor along our western foothills (max of 18% at Derby Mtn Raws) so have adjusted min RHs today a bit. Should see values near 10% at Livingston/Nye with temps near 90F. Higher humidities will exist in the east as we begin to bring cooler air from Canada. Next surge of pressure rises arrives tonight. In the meantime, air quality will remain poor and may worsen before we see some improvement tomorrow. JKL && .DISCUSSION... Today through Wednesday Night... Above normal temperatures and dry weather will continue through today with everything indicating another round of thickening smoke. A stronger push of colder air tonight from the north/northeast will mean notably cooler conditions for Wednesday, and reduce the smoke a good deal, especially over the plains. Those with outdoor plans should take precautions for poor air quality over the next 24-30 hours. BT Thursday through Tuesday... Temps will remain above seasonal average through the extended forecast period, with the exception of near normal temps on Sunday, when temps will be in the lower 70s in most locations. Upper level ridging will build over northern Idaho, bringing shallow dry northwest flow across the region Thursday. Upper level ridging will shift east across the region Thursday evening/night and Friday, ahead of the approaching Pacific trough. Expect high temps in the 80s for Thursday and Friday. Southwest flow aloft begins over western mountains by Friday afternoon, with showers expected to develop in the western mountains early Friday afternoon. The upper level Pacific trough will cross the region Friday night through Sunday evening. Expect widespread showers across the region through this period, with the best chance for precip will be over high terrain Friday night through Saturday morning. Shallow ridging will return to the region late Sunday evening/night through Monday, with generally zonal flow for Tuesday, for a return of dry conditions across the region. Gilstad && .AVIATION... Smoke from west coast wildfires will continue to infiltrate the area through the period. Slant range visibility will remain reduced. Surface visibility is expected to decrease to MVFR across much of the region today, with local IFR possible, especially along the western mountains. Otherwise, strong high pressure aloft will keep the region dry with only occasional high clouds. JKL && .PRELIMINARY POINT TEMP/POPS... Tdy Wed Thu Fri Sat Sun Mon ------------------------------------------------------- BIL 088 051/076 050/082 052/084 055/075 051/072 047/078 0/K 00/H 00/U 01/B 24/W 42/W 10/U LVM 089 045/083 047/086 047/084 048/071 044/070 041/077 0/K 00/H 00/U 01/B 57/T 52/W 11/U HDN 087 048/079 046/084 051/086 053/078 049/072 045/078 0/K 00/H 00/U 00/U 14/W 53/W 10/U MLS 083 049/073 047/079 050/080 054/079 051/071 046/077 0/K 00/B 00/U 00/B 13/W 53/W 10/U 4BQ 086 049/077 048/081 051/083 056/082 051/071 046/077 0/K 00/H 00/U 00/U 03/W 43/W 10/U BHK 080 046/069 045/075 045/073 049/078 049/070 044/074 0/K 00/U 00/U 00/N 02/T 53/W 10/U SHR 087 048/082 048/085 049/087 052/079 045/072 043/077 0/K 00/H 01/U 11/U 25/T 53/W 10/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings