Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
760 FXUS65 KBYZ 090908 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 308 AM MDT Thu May 9 2024 .DISCUSSION... Today through Friday Night... Satellite imagery showed deep northeasterly flow over our region rotating around a large upper low over the NE/SD border extending SW into Utah. Currently some drier air had infiltrated over our eastern zones and fog was developing due to the rich moisture in the lower boundary layer. Scattered to numerous showers continued over our western zones flowing into our mountains. Our current precipitation is being driven by warm air advection circulating around the weather system, and aided by associated jet dynamics and of course deep upslope flow. This is all creating strong moisture convergence from Yellowstone County southwestward into the Beartooths. Models indicate a continued stream of moisture and lift into our western zones today...and as instability picks up this afternoon we will see shower coverage increase again over our eastern zones as well. PoPs generally range from 100% over our north facing slopes to 20% in Fallon County. The main focus of precip will almost certainly be in areas from Billings south and southwest. Cross sections do indicate omega weakens and moisture becomes more shallow this afternoon. Thus, intensity of snowfall and other precip should continue, but be decreasing later today (high Pop and lower QPF scenario). Tonight...upper support for ascent will continue to weaken from north to south with precip coverage decreasing in similar fashion...and lingering over just our mountains by late tonight. Clouds will be decreasing as well and with plenty of low level moisture in the boundary layer, we expect to see areas of fog develop by Friday morning. After any fog burns off Friday...high pressure aloft will prevail leading to a pleasant spring day with highs warming into the 60s for most locations. Snowfall...Our winter storm warnings are valid through noon today. There is still several more inches possible through the rest of tonight and this morning. (prob of >6 additional inches up to 65%), but the snowfal rates and intensity should be notably lower by afternoon. Hydro Issues...Despite the relatively prolific widespread precipitation we have received...rivers are behaving themselves. The rise on the Tongue at Miles City is now down to 5 ft after peaking at 7.35 ft (flood atage 10 ft) and others are trending down as well. BT Saturday through Thursday... High pressure building into the region will bring warmer and mainly dry conditions for the weekend, with highs in the 70s through Monday. Confidence is high for above normal temperatures, with a greater than 70% chance of exceeding 70 degrees Saturday through Monday. Weak energy causing the ridge to flatten some on Sunday will bring low chances (15-30%) for afternoon showers. A shortwave dropping into the area from the northwest is progged for the second half of Monday, continuing through Tuesday. Showers and thunderstorms are possible (currently 30-50% chance), greatest near the foothills. Cyclonic flow will keep the potential for showers/thunderstorms through the middle of the week, along with cooler temperatures. The upcoming warmer temps will melt much of the wet snow that is currently falling at elevations between 6000-8000 feet. At this time we do not see a flood risk, but rivers/streams emerging from the foothills will likely see some rises this weekend. STP && .AVIATION... Showers and mountain snowfall will continue to affect the area today, with the greatest shower coverage west of KMLS and near the mountains and foothills. Showers are expected to decrease this evening. MVFR to IFR can be expected with the showers, with the poorest flying conditions along the foothills. Mountains will be obscured due to snow. Local LIFR conditions are possible over portions of the area this morning due to fog. STP && .PRELIMINARY POINT TEMP/POPS... Tdy Fri Sat Sun Mon Tue Wed ------------------------------------------------------- BIL 059 041/066 044/075 048/077 051/078 050/069 046/069 7/R 40/U 00/U 12/T 12/T 35/T 34/T LVM 053 036/064 038/071 044/074 046/074 045/069 042/067 5/R 20/U 00/U 01/U 12/W 25/T 33/T HDN 061 040/067 039/076 045/078 048/078 048/070 044/069 6/R 40/U 00/U 12/T 13/T 45/T 34/T MLS 064 042/068 042/075 047/076 050/078 050/069 043/069 3/R 20/U 00/U 12/T 12/T 34/W 22/T 4BQ 061 043/066 041/075 047/076 049/077 048/069 043/068 5/R 20/U 00/U 01/U 12/T 44/T 22/T BHK 064 038/067 041/074 045/076 047/077 046/067 040/066 2/R 10/U 00/U 02/T 13/T 34/W 22/W SHR 056 039/065 036/072 042/074 045/075 045/067 042/066 6/R 41/U 00/U 02/T 13/T 56/T 44/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning remains in effect until noon MDT today FOR ZONES 67-68-171. WY...Winter Storm Warning remains in effect until noon MDT today FOR ZONE 198. && $$ weather.gov/billings