Area Forecast Discussion
Issued by NWS Billings, MT
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Issued by NWS Billings, MT
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-- Discussion containing changed information from previous version are highlighted. --718 FXUS65 KBYZ 260151 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 751 PM MDT Sat May 25 2024 .UPDATE...-- Changed Discussion --With ongoing showers across the CWA, adjustments to the PoPs and chance of thunder were made. Matos-- End Changed Discussion --&& .DISCUSSION...-- Changed Discussion --Today through Sunday night... Today will see precipitation chances and more active weather return to the region. A couple upper waves will move across the region creating a low pressure system to the north of us. A weak cold front will move across the region bringing showers and thundestorms along and behind it starting around 21Z this afternoon. CAPE values will be low with values generally below 500J/kg limiting updraft potential. Shear will also be limited with 0-6km bulk shear values being in the 20-30kt range. Looking at soundings, there will be speed shear in the atmosphere but directional shear will be almost nonexistent. The speed shear could tilt some updrafts and prolong some thunderstorms but overall thunderstorm potential looks limited. Due to these factors, the Storm Prediction Center has the region in a general thunderstorm risk for today. These showers and thunderstorms will persist through the overnight before exiting into the Dakotas tomorrow morning. Most locations west of Billings have a 50-80% chance of getting >0.10 inches of precipitation while locations to the east have a 20-40% chance. Sunday will see gusty westerly winds come in behind our system as pressures start to rise. Most of the region will see wind gusts into the 30s kts throughout the day. Increasing 700mb winds into the 30s kts and steep low level lapse rates in the 8-9C/km range leading to efficient mixing will be the main reasons for this. Most of the region will have a 30-60% chance for a wind gust over 30mph with higher chances for western gap areas and lower chances for area near the Dakotas border. Temperatures today and tomorrow will be in the mid 60s to low 70s fo most. Torgerson Monday through Saturday... An upper ridge will build and move eastward over the Northern Rockies Monday into Monday night. As this pattern evolves, temperatures aloft will warm and with some downsloping flow will help to warm surface temperatures to the 60s and 70s. On Tuesday, upper ridge will move farther eastward so that the ridge axis will approach the MT/Dakota border. Low-level winds will turn more south-southeasterly which will facilitate further warming with high temperatures in the 70s to lower 80s. In the afternoon and evening, areas west of Billings will be under some cyclonic southwesterly flow with a 20-40% chance of showers and thunderstorms in the western mountains and foothills. With the warming temperatures and recent snowfall in the mountains, there is concern for snow melt to cause waterways to run high. Any property and/or recreation on waterways should be considered during this warm period. Wednesday, a cold front will cross the area from west to east. South/southeasterly winds east of the front will encourage instability over southeast MT with NBM showing a 30% chance of CAPE reaching 1000 J/kg over far eastern MT. However, shear will be lacking so not expecting much in the way of severe weather at this time. There will be isolated-scattered showers and thunderstorms (20-40% chance) in southeast MT from the front. Then behind the surface front, an upper air disturbance moving northeastward over Montana will bring large scale ascent and 700 mb frontogenesis and a 60-90% chance of showers and isolated thunderstorms to south central MT. NBM shows mean precipitable water values range from ~0.6 to ~0.9 inches Wednesday evening with the highest PW values over southeast MT. However, greatest dynamics are over south central MT. So if a thunderstorm were to form over southeast MT it could drop some localized heavy rainfall. Otherwise, over south central MT, NBM shows a 20-50% chance (greatest in mountains) of receiving at least 0.50 inches of rain from this system. Snow is also expected Wed. night above 8500 feet with 1-2 inches of accumulation. Model solutions begin to differ on Thursday with 2 clusters showing a deeper upper trough over the Pacific Northwest while 2 other clusters place the upper trough more to the north in western/central Canada. The deeper trough over the PacNW would mean wetter weather for our area while the more northern placement and eventual upper ridging would mean drier weather. Given these differences NBM has a 20-50% chance of showers and thunderstorms each day Thursday-Saturday. Precipitation should be in the form of snow above 7500-8500 feet but currently snowfall amounts look light. High temperatures will generally be in the 70s and 80s Wednesday then 60s to 70s Thursday through Saturday. TS/RMS-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --Scattered showers and a few thunderstorms will continue across the area overnight. Local MVFR is possible within the heavier showers. Mountain obscurations are likely. Winds will be gusty tomorrow with most locations gusting 25 to 35 mph. BT/Torgerson-- End Changed Discussion --&& .PRELIMINARY POINT TEMP/POPS...-- Changed Discussion --Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 047/066 044/073 047/080 054/079 049/065 045/067 046/073 72/R 00/U 00/U 15/T 64/T 33/T 22/T LVM 040/063 038/071 044/080 051/075 042/060 038/065 041/071 70/N 00/U 01/U 38/T 65/T 34/T 22/W HDN 046/067 040/073 044/082 052/081 049/068 044/068 044/075 74/R 10/U 00/U 14/T 63/W 33/T 22/T MLS 048/066 045/071 045/080 055/083 051/070 046/069 046/074 63/R 10/U 00/U 11/B 52/W 32/T 22/W 4BQ 047/066 045/069 046/080 054/085 051/071 046/067 046/074 64/R 00/U 00/U 01/U 42/W 32/T 22/T BHK 044/065 042/068 042/077 050/081 050/071 044/067 044/072 44/R 10/U 00/U 01/U 52/W 32/W 22/W SHR 041/064 041/069 044/080 051/082 047/068 041/066 041/073 56/T 10/U 00/U 03/T 53/T 32/T 22/T-- End Changed Discussion --&& .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings