Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
964 FXUS65 KBYZ 040327 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 927 PM MDT Mon Jun 3 2024 .UPDATE... Reports of whiteout conditions on the highest portions of Beartooth Highway have resulted in MTDOT closing the pass on the Montana side this evening. Expect an additional 3 to 5 inches on the pass tonight, along with strong wind gusts around 50 mph and a few evening thunderstorms. Near whiteout conditions are likely to persist after snow ends late tonight, likely into the day Tuesday. Freezing levels drop to around 7500 feet overnight and temperatures on top of the pass look to be in the mid 20s tonight. Put out a winter weather advisory for this area until 9 am tomorrow morning. Line of showers and thunderstorms has traversed the forecast area this afternoon/evening. winds gusting mainly in the 30 to 50 mph range have been the main impact from this activity, with a few gusts over 50 mph. Expect this activity to shift into the Dakotas by midnight. Additional light shower activity will shift through the area tonight, before ending tomorrow morning as the stronger downslope synoptic winds develop. A windy day remains on tap for Tuesday with some strong gusts likely in the western foothills. Going wind highlites are in good shape, no changes planned to those this evening. Chambers && .DISCUSSION... Rest of Today through Wednesday... Satellite imagery showed a strong upper trough pushing into the northern Rockies from Washington state while several minor perturbations could be seen in the W/SW flow over Montana. Sct showers and some thundestorms had developed over SW Montana and were spreading east into the central sections of the state. Upper low will track across Canadian border and push/drag cold front across our CWA this evening providing forcing for convection. Look for frontal passage between 7 pm and 9 pm at Billings shifting winds to NW with increasing chance of showers/thunderstorms along this boundary as it pushes E/SE. Latest analysis indicated around 500 J/kg CAPE values over our western and central zones attm which are progged to possibly reach over 750 J/kg by evening as convection spreads into our CWA. This is sufficient for some stronger thunderstorms capable of producing brief heavy rain and gusty winds early this evening. A few hundredths of an inch of QPF is expected for most locations. However, higher amounts are possible with stronger cells, with some local spots seeing 0.1-0.2". Main threat though seems to be local wind gusts 50-55 mph early this evening in our west (Billings west to Livingston) associated with cells along cold front. The cold front is expected to depart the region after midnight with the upper low pushing into the Dakota/SW Saskatchewan area overnight. Strong subsidence associated with a powerful 125kt 250mb jet will fill in behind the upper low over our western zones. Corresponding 700mb winds will increase across our western zones. Low level lapse rates are progged to be 6.5-8 C/km creating a mix down scenario Tuesday. Wind is expected to increase early Tuesday and spread east as we mix out with diurnal heating. The strongest winds are expected in our western foothills. We have upgraded our high wind watch to a warning, and also added a wind advisory from Livingston to the Beartooth foothills. Keep in mind, high winds like this are not typical this time of year (more of a Fall and Winter feature), so there is uncertainty how this will play out. Here is a breakdown of wind potential per each unique section of our CWA. Wheatland County (Harlowton vicinity)...Forecast soundings suggest a very shallow weak inversion forms after midnight which may delay onset of strong winds...but we could still see strong winds as early as midnight. Strongest will be during the middle to latter part of Tuesday. Winds may back off Tuesday night before increasing again Wednesday as even strong 700mb winds develop overhead. Models all want to hit strongest gusts (60-65 mph) Tuesday...but strongest 700mb winds are Tuesday night into Wednesday but may not be as bad due to a somewhat more shallow mixing layer. Big Timber Vicinity...Strongest winds expected Tuesday with diurnal heating, but strong winds may continue Tuesday night into Wednesday morning as 700 mb speeds are even stronger during this time frame (60-70kts). Again, significant uncertainty with onset and duration of winds (will it be that strong into Wednesday?). Livingston Area...Wind Advisory from 600 AM to 1200 AM Wed. Wind directions (westerly) do not favor true gap flow nor does the seasonality. However...very strong 850-700mb winds with deep mixing per Bufkit soundings on both GFS/NAM suggest max wind gusts 50-60 mph a good bet (60 mph Prob 55%). Wind gusts should peak midday. Wednesday does not look as favorable as 700mb wind max is a little further north and mixing not as deep...but gusts 35-45 mph still expected. This will need to be monitored though...in case 700mb wind forecast shifts a bit further south on subsequent model runs. Eastern Plains...Biggest question mark. We may see some locally strong winds this evening and overnight with frontal passage and some showers around (gusts 45-50 mph). Look for brisk winds Tuesday, increasing by Tuesday night. Powerful 700mb wind max over east central Montana late Tuesday night into Wednesday. We currently expect sub warning winds (gusts 45-55 mph) from Rosebud eastward on Wednesday. Strongest will be Wednesday over Baker vicinity (Prob 25% for 60 mph gust at Baker). The downslope winds and subsidence will mean dry conditions Tuesday through Wednesday. Highs will be in the 70s while overnight lows range from 40s tonight to mid 50s Tuesday night. BT Wednesday Night through Monday... The long term will generally see a calm pattern persist with above average temperatures and dry conditions. Thursday and Friday have good model agreement that ridging will be over the region bringing temperatures in the high 70s to mid 80s. Once we get into the weekend, there is more uncertainty in the WPC clusters. For Saturday, about 50% of the clusters have ridging remaining in place and the other 50% show a trough sliding along the north of the ridge bringing cooler temperatures. Sunday is similar with about 60% of models maintaining ridging and the other 40% showing the ridging breaking down. Once we get out to Monday there is even less ensemble agreement in the pattern but about 25% of models are showing a trough to our west bringing the potential for widespread precipitation over the region again. Temperatures over the weekend will be in the 80s for most with inherent uncertainty given the potential patterns. Temperatures look to drop a few degrees on Monday into the mid 70s to low 80s. Given these above average temperatures and a snowpack that is near freezing and ready to melt, we will be watching area rivers and streams for any potential rises. All river and stream gauges are currently well below any flood stage indicating they can handle increased water flows. Due to this there are currently no flooding concerns. Torgerson && .AVIATION... Showers and embedded weak thunderstorms from KBIL S and E, with rain and snow over the mountains, will decrease from NW to SE through the night. MVFR is expected in the precipitation, and mountain obscuration will decrease through the night. Wind gusts to 50-55 mph are possible near stronger storms, especially E of KBIL. Late tonight behind this system, strong westerly winds may develop in our foothills. Look for gusts of 25-45 kts along the western foothills tonight. The potential for strong winds 30-45 kts will spread east on Tuesday. TS POTENTIAL TIMES: KMLS: through 07Z KSHR: Slight chance through 12Z Arthur && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 047/074 055/078 049/081 056/085 057/084 059/086 059/079 50/N 00/N 00/U 01/U 11/U 12/T 33/T LVM 042/071 054/077 047/084 054/085 054/084 054/083 052/077 10/N 00/N 00/U 02/T 11/U 13/T 45/T HDN 047/075 053/077 046/081 054/085 055/085 056/088 057/080 70/N 00/N 00/U 00/U 10/U 11/U 33/T MLS 049/074 054/072 046/079 052/085 055/083 056/086 057/080 60/N 00/N 00/U 00/U 00/U 01/U 32/T 4BQ 051/072 055/073 047/079 054/086 055/084 057/087 057/080 50/N 00/N 00/U 00/U 11/U 11/U 33/T BHK 048/071 051/071 044/078 049/082 050/080 052/082 054/078 40/N 00/N 00/U 00/U 00/U 00/U 22/T SHR 044/074 049/076 046/081 053/085 053/083 054/086 054/079 61/U 00/N 00/U 01/B 11/B 12/T 34/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...High Wind Warning in effect until noon MDT Wednesday FOR ZONES 63-228. Wind Advisory in effect from 6 AM Tuesday to midnight MDT Tuesday night FOR ZONES 65-66. High Wind Warning in effect from 6 AM Tuesday to noon MDT Wednesday FOR ZONES 141-172. WY...None. && $$ weather.gov/billings