textproduct: Billings

KEY MESSAGES

- Cold front arrives this afternoon/evening, bringing a sharp drop in temperatures and rain changing to accumulating snow. A flash freeze with roads quickly turning icy may result in treacherous travel conditions this evening into tonight.

- Hazardous winter conditions continue Friday into Saturday morning with accumulating snow. Greatest accumulations over the plains, generally from Harlowton to Billings and eastward towards Miles City and Ashland, where 5 to 10 inches of snow are forecast.

- Cold temperatures over the plains tonight through Saturday night. Prepare for the cold!

- Warmer and drier weather expected to return by Sunday through early next week.

AVIATION

00Z Discussion...Two cold fronts working through the area tonight. The first has modified Canadian air has sagged southwest into the foothills late this afternoon. The colder Arctic front is just moving into the northern tier of our area. Winds have turned northerly behind the initial front and will shift more easterly as we go through the night tonight, at much lighter speeds than we have seen the past few days. Rain is filling in behind the initial front and will be widespread over the next couple of hours, transitioning to mainly snow as the arctic front moves in later tonight. With the much colder air expect low stratus and fog to be widespread along with increasing snowfall rates resulting in IFR to LIFR conditions being common across the area with local VLIFR in heavier snowbands. KBIL may be impacted by VLIFR conditions around the early morning push. Cold air starts to push back out of the area Friday afternoon which will move the band of precipitation more into SE Montana by late in the day Friday.

One big adjustment to this TAF issuance was the addition of Freezing Rain to the KLVM TAF overnight tonight. The HRRR is showing the Arctic cold arriving in a very shallow near surface layer late tonight setting up conditions for 3 to 6 hours of freezing rain. Other deterministic models are pushing cold air in deeper with mainly light snow forecast. For this issuance went with -FZRASN mix during this period but may need to go stronger with this potential as the system evolves. Hope to see signs of the cold air depth heading toward KLVM over the next 3 to 4 hours.

Cold air doesn't quite reach the top of our mountains tonight so expect turbulence to continue to be an issue near area mountains tonight above the frontal inversion. Icing will definitely be a concern over the western half of the forecast area as well tonight into the day Friday. Chambers

PRELIMINARY POINT TEMP/POPS

Tdy Fri Sat Sun Mon Tue Wed ------------------------------------------------------- BIL 063 012/015 008/020 011/047 033/047 040/049 033/044 8/R 99/S 32/S 00/B 00/B 02/R 44/O LVM 060 020/035 028/040 034/054 035/053 039/051 032/044 6/R 98/O 11/N 00/N 00/N 13/R 55/O HDN 059 011/015 006/020 008/043 023/045 033/048 031/044 8/R 99/S 63/S 00/B 00/B 02/R 45/O MLS 046 004/007 902/010 000/039 025/041 031/045 029/041 2/O 59/S 91/E 00/U 00/B 01/B 33/O 4BQ 053 010/014 007/017 009/043 027/044 033/047 031/044 4/R 69/S 72/S 00/U 00/B 01/B 23/O BHK 043 902/004 907/007 904/045 025/043 030/046 026/040 2/O 29/S 91/B 00/U 00/B 01/N 23/O SHR 063 014/025 010/030 018/055 028/054 034/054 029/047 7/R 96/S 22/S 00/U 00/U 01/B 34/O

BYZ WATCHES/WARNINGS/ADVISORIES

MT...Winter Storm Warning in effect until 11 PM MST Friday FOR ZONES 29-42-63-173-228. Winter Weather Advisory in effect until 5 AM MST Friday FOR ZONES 30>32. Winter Storm Warning in effect from 5 AM Friday to 8 AM MST Saturday FOR ZONES 30>32. Winter Storm Watch in effect Saturday morning FOR ZONES 30>33-36-37. Winter Weather Advisory in effect until 8 AM MST Saturday FOR ZONES 33-36-37. Winter Storm Warning in effect until 8 PM MST Friday FOR ZONES 34-57-58-68-138-141-172-235. Winter Weather Advisory in effect until 9 AM MST Friday FOR ZONES 40-56-65-66-139. Winter Weather Advisory in effect until noon MST Friday FOR ZONES 169>171. WY...Winter Weather Advisory in effect until noon MST Friday FOR ZONES 198-199.