textproduct: Billings

KEY MESSAGES

- Light rain/snow showers and mountain snow this morning. - Winter storm setting up to impact the region tonight through Friday. Periods of moderate to heavy snow over the mountains, Bighorn foothills, and near the Dakota border.

- Widespread gusts 25 to 40 mph, with a few gusts over 50 mph over the Bighorn foothills tonight through Friday.

- Wet, cool, and windy conditions will be hazardous for young livestock. Travel and outdoor activities will be impacted by wintry conditions.

- Turning drier and warmer over the weekend.

UPDATE

Area of stratus/fog continues to advected westward from the Dakotas into southeast MT, making it thru Miles City and Broadus as of 09z. Baker vsby is down to 4SM with a 300' ceiling. Areas near the Dakotas border could see a saturated boundary layer deepen enough to support patchy light freezing drizzle. Have added mention of fog/-fzdz to our east thru 16z. Something to watch.

The main show is the upcoming storm system, with a low that is currently over western WA and dropping slowly southeastward. Still expecting showers and a few t-storms this afternoon and evening, followed by a changeover to wet snow tonight. Uncertainties still exist with the track of the mid level low and this will affect locations of greatest pcpn, of course. The forecast has all of this covered well but have made a couple highlight changes, as described below.

Have upgraded the Winter Storm Watch to a Winter Storm Warning for Fallon, Carter & Powder River. These zones are looking at a 4-8" snowfall, greatest over the hills. Lesser amounts will fall in Custer (per the expected track of the low) and have issued a Winter Wx Advisory here. In our west, high res models are suggesting post-frontal boundary layer winds near 50 knots for a few hours through Judith Gap (favored by north winds), which along with a little snow warrants an Advisory for this area. Also, as mid level flow shifts to the NW tonight, with reasonably steep lapse rates, the Paradise Valley should be favored for a few inches of snow. The western slopes of the Absarokas to the east of US-89 could see localized higher amounts if some banding develops. Otherwise, no changes to the Advisories and Warnings already issued.

Billings remains in a difficult spot regarding snowfall, and even precip in general. If mid level winds become NE/cyclonic tonight (per the GFS) for a period of time, that favors some snow accumulation late tonight into Friday despite the NW surface winds. If the mid level winds remain northwesterly (as the EC shows) Billings could nearly miss out entirely on snowfall, with the trowal setting up to our east. Either way, surface conditions will not be cold enough to prevent some melting, so the highest accums (if any) will be over the surrounding higher hills. Not an easy forecast so please continue to monitor for changes.

JKL

AVIATION

Areas of low stratus w/ embedded fog is spreading westward from the Dakotas, and will impact eastern sites (KMLS-KBHK-K97M) with IFR-LIFR through ~16Z. Further west there is potential for localized fog but this is of much less confidence (20% chance). Shower chances will increase through the day as a dynamic low pressure system approaches from the west. Showers and even a few embedded thunderstorms will become common after 21z, with local MVFR in the shower activity. Tonight, as the low becomes more organized, rain showers will mix with and change to wet snow. This will result in poor flying weather with MVFR-IFR being common. Mountains will be occasionally obscured today, then completely obscured tonight as accumulating snow develops. East winds will gust 15-25 knots in the east. In the west, light winds in the morning will shift to breezy W-NW winds (gusts 20-30 knots) starting around 21z. JKL

PRELIMINARY POINT TEMP/POPS

Tdy Fri Sat Sun Mon Tue Wed ------------------------------------------------------- BIL 056 032/042 030/062 034/062 035/058 037/072 038/053 5/T 98/O 10/U 00/U 01/B 00/U 34/W LVM 048 029/048 028/057 032/061 033/060 037/067 036/052 8/T 85/O 00/U 00/U 00/E 01/N 34/W HDN 059 030/040 026/062 030/061 032/061 034/073 036/056 5/T ++/O 20/U 00/U 11/B 00/U 24/W MLS 055 029/035 025/055 030/055 030/051 032/069 035/051 4/W 9+/S 10/U 00/B 10/E 00/U 12/W 4BQ 058 029/034 025/053 030/056 031/051 033/069 037/055 4/W 9+/S 40/U 00/U 11/B 00/B 22/W BHK 044 024/032 022/047 027/049 025/043 025/062 032/050 2/W 8+/S 40/B 00/B 11/E 00/N 12/W SHR 057 030/036 024/054 027/057 029/059 033/069 034/053 6/T ++/S 30/U 00/U 00/B 00/U 24/W

BYZ WATCHES/WARNINGS/ADVISORIES

MT...Winter Weather Advisory in effect from 6 PM this evening to 6 PM MDT Friday FOR ZONES 30-31-57-173-235. Winter Weather Advisory in effect from 9 PM this evening to midnight MDT Friday night FOR ZONE 32. Winter Storm Warning in effect from midnight tonight to 6 AM MDT Saturday FOR ZONES 33-36-37. Winter Storm Warning in effect from 9 PM this evening to midnight MDT Friday night FOR ZONES 58-138-169. Winter Weather Advisory in effect from 6 PM this evening to noon MDT Friday FOR ZONES 63-64. Winter Storm Warning in effect from noon today to 6 PM MDT Friday FOR ZONES 67-68. Winter Storm Warning in effect from 6 PM this evening to 6 PM MDT Friday FOR ZONE 171. WY...Winter Storm Warning in effect from 9 PM this evening to midnight MDT Friday night FOR ZONE 199. Winter Storm Warning in effect from 6 PM this evening to 6 PM MDT Friday FOR ZONE 198.