textproduct: Billings

KEY MESSAGES

- Cold front today brings breezy northwest winds, cooler temperatures and rain/snow into Tuesday. Several inches of snow can be expected in the mountains with light snow accumulations for portions of the lower elevations.

- Brief warmup midweek.

- Another period of cooler temperatures and rain/snow late week. Increasing confidence in a dynamic and impactful weather system.

UPDATE

Evening light showers have moved on and current wx is dry under scattered to broken mid and high clouds, as we await the Canadian cold front which appears to have just moved through Cut Bank. Surface analysis is currently convoluted as we are seeing a push of NE winds over the lower elevations as downslope winds remain along the western foothills. Winds aloft are strong over our southern mtns, with gusts to 65 mph at Quad Creek (9774') and 56 mph at Burgess Jct (7743'). With this in mind will need to monitor surface conditions as we begin to mix, to see if perhaps any gusty downslope winds emerge at Red Lodge and Sheridan. It is possible that our backdooring pre-frontal wind shift negates these potentially warmer/drier downslope winds. HRRR continues to show a brief window of gusty west winds in the mid afternoon just prior to the main cold front's arrival. Precip will develop this afternoon behind the fropa along a healthy axis of mid level frontogenesis, which will sag to the south thru the evening. Forecast has all of this covered well, but did tweak the onset of precip in our north, which should occur in the 15-18z time frame.

Confidence is high that rain will mix with and change over to wet snow, with highest chances of snow accumulation over the higher elevations south of Billings...though would not be surprised to see a little wet snow on the grass in Billings this evening especially if low level winds are able to turn more easterly. Models continue to highlight the Red Lodge foothills for greatest snow accumulations outside of the mountains. Have issued a Winter Wx Advisory for this area for 2" to locally 6" of snow, and difficult travel conditions as temps fall below freezing this evening. The start time of this advisory is 6pm.

Interestingly, as ascent from the main shortwave exits we see a backing of mid level winds and modest isentropic ascent from the SW by early Tuesday. It is possible that upslope snow along the western/southern foothills doesn't actually stop early Tuesday and continues for much of tomorrow per another wave lifting thru the great basin. Interesting set up. This will also keep Tuesday quite chilly with western areas likely to not warm above the 30s. Upslope stratus in our west could also be a factor tomorrow. JKL

AVIATION

VFR this morning will give way to deteriorating flying weather this afternoon and evening as a Canadian cold front drops through the area. Before the front, SW-W winds will be gusty along the foothills (gusts 25-35 knots). Expect a shift to brisk NW-N winds behind the front with widespread 20-30 knot gusts into the evening. An area of post-frontal rain/wet snow moving north to south will produce MVFR and local IFR. This will impact KBIL, KLVM & KSHR for much of the night. Mountains will be obscured from late this afternoon through tonight. There may be a risk of fog and low stratus late tonight especially in the west as upsloping easterly winds develop, but this is of low confidence at this time. JKL

PRELIMINARY POINT TEMP/POPS

Tdy Tue Wed Thu Fri Sat Sun ------------------------------------------------------- BIL 059 026/045 029/052 035/056 033/045 028/059 035/066 6/O 93/S 42/O 27/T 86/W 31/U 11/U LVM 059 023/041 029/055 035/051 030/045 028/056 033/063 7/O 86/S 75/O 69/T 75/J 21/U 00/B HDN 062 023/048 028/054 033/058 030/043 026/058 031/066 5/R 92/S 22/O 27/T 98/W 42/J 11/U MLS 059 023/043 030/048 030/051 029/038 024/046 027/060 3/R 60/B 22/O 14/O 77/J 31/B 11/U 4BQ 067 026/044 031/050 030/055 030/038 024/048 029/061 1/B 61/B 23/O 24/O 88/J 42/J 11/U BHK 061 020/040 023/040 025/040 024/036 022/043 024/055 1/N 40/B 23/S 23/S 77/J 31/B 11/B SHR 074 025/047 029/050 030/058 026/039 024/053 028/063 3/N 85/S 34/O 37/T 98/J 42/J 11/U

BYZ WATCHES/WARNINGS/ADVISORIES

MT...Winter Weather Advisory in effect from 6 PM this evening to 9 AM MDT Tuesday FOR ZONE 56. WY...None.