Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
461 FXUS65 KBYZ 300845 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 245 AM MDT Tue Apr 30 2024 .DISCUSSION... Today through Wednesday... Showers associated w/ a fairly dynamic Pacific trof continue to move west to east thru the forecast area tonight. The back edge is nearing Billings at 08z. Precip over the last six hours has been a tenth of an inch or less across the north and east, but a heavier area of precip associated with the trof axis itself has resulted in 0.10-0.25" from the foothills to Billings. A nice drink of water indeed. The Beartooth-Absarokas saw a period of heavy snow, and Snotels are suggesting something like 3-6". Wet snow has also fallen along the foothills but with little accumulation below ~5kft. Showers will move through southeast MT over the next several hours and should end by 12-15z as subsidence arrives from the west. Gusty well-mixed west winds will develop across the region today. Mid level flow around 35kts suggests peak gusts in the 30-45 mph range. By afternoon we will see pressure falls to the west, i.e. the isallobaric wind will work against the westerly flow, so don`t see a risk of 50+ mph gusts (probability of this is only 10% across our north). Pwats falling to 0.20" or less will yield dewpts in the teens. Even with the cooler temps we should see afternoon humidity down to the upper teens to mid 20s most places. An upper low w/ cold air aloft exists over southern BC, and satellite imagery shows the next shortwave of interest along the WA coast. Despite the large scale subsidence today, the cooling aloft (near -30C at 500mb) will yield enough diurnal/shallow instability to produce isolated to scattered rain/snow showers (maybe graupel?) mainly near the western and southern mountains & foothills (but these could reach Billings by late afternoon). Then tonight as next wave approaches, we should see greater potential for showers especially from Billings westward and southward (30-50% chance). Shower coverage should increase Wednesday as the trof passes thru. Given the steep lapse rates through the period, the Beartooth Absarokas will see a few more inches of snow (probability of 3+ inches is ~60%). Lower elevation precip will be a tenth of an inch or less. Winds on Wednesday will remain breezy but not to the extent of today. Expect 20-30 mph gusts tomorrow. One thing to note is that with the dry boundary layer, wet bulb zero heights will be low enough to produce some wet snow along and near the foothills with any heavier shows tonight thru Wednesday. This will not be necessarily impactful (per warm surface temps) but may result in localized poor visibility. Something to watch if you will be out and about. We are entering a stretch of cooler than normal days. Look for highs in the upper 40s and 50s both today and Wednesday. JKL Wednesday night through Monday... Cyclonic flow over northeast MT will continue to bring periods of precipitation to the region through Friday. Chances for at least a tenth of an inch are most likely for the central and western portions of the region through Friday evening. The chance of precipitation for most of the region remains at around 30-50% with the best time being the afternoon hours. With snow levels around 5000 ft during this same time period, the foothills have about a 50% chance of getting an inch of snow, with the mountains likely to get a few inches. Ensembles are in agreement that ridging will build in for the weekend allowing for warm and dry conditions. Agreement between ensembles is also strong for a Pacific low to enter the region Sunday night into Monday. However, there is variance on the track of this system, so this will be something to watch as that time approaches. There does appear to be a strong push of moisture with above average precipitable water values. Chances for at least a quarter inch of precip Monday look to be around 25% for the region with precip chances likely to continue through the week. High temperatures will be in the 50s through Friday, warming into the 60s/low 70s for the remainder of the period. TS && .AVIATION... Showers w/ local MVFR will shift eastward thru the remainder of the night...ending at KBIL by 09z, KMLS by 13z and the Dakotas border by 15z this morning. Today will be windy with VFR prevailing. Look for westerly wind gusts of 25-35kts across lower elevations, affecting all TAF sites. Winds will decrease by evening. This afternoon through tonight, a weak disturbance from the west will bring scattered rain/snow showers west of KMLS and K00F. Mountains will be frequently obscured in snow showers. JKL && .PRELIMINARY POINT TEMP/POPS... Tdy Wed Thu Fri Sat Sun Mon ------------------------------------------------------- BIL 056 035/055 037/053 034/054 033/065 042/073 046/069 2/W 23/W 35/W 34/W 11/U 02/W 34/W LVM 050 029/049 033/049 030/052 030/063 039/066 041/064 4/W 45/W 45/W 44/W 11/B 13/T 34/W HDN 058 033/057 034/054 032/055 030/067 040/078 045/071 2/W 23/W 37/W 34/W 11/U 02/W 34/W MLS 057 035/058 035/052 032/052 031/062 041/076 047/069 2/W 02/W 25/W 23/W 11/U 01/B 34/W 4BQ 057 033/057 034/053 032/053 031/064 040/078 047/068 2/W 02/W 25/W 23/W 11/U 01/B 33/W BHK 056 030/057 031/051 029/050 029/059 036/073 045/067 3/W 01/B 25/W 23/W 11/U 01/B 34/W SHR 056 030/053 030/052 029/051 027/064 037/075 043/067 2/W 24/W 45/W 35/W 21/U 02/T 34/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings