Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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812 FXUS65 KTFX 080223 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 823 PM MDT Tue May 7 2024 .UPDATE... The only tweak with the evening update was to increase snow amounts in the Belt to Geyser corridor as well as in the Lewistown areas tonight. Localized snow amounts in these areas may exceed 6 inches in total, but given the limited spatial extent of this amount of snow, I opted to hold off from any upgrades at this time. Forecast guidance continues to advertise periods of snow mixing in at Great Falls late tonight as snow levels briefly lower to around ground level in northern Cascade County. High resolution models only favor snow as the dominant precipitation type in town for a few hours late tonight, with snow levels beginning to rise later tonight as warmer air aloft begins to nudge in from the northeast. For that reason I have held off from increasing snow amounts around Great Falls to more than a couple inches, but it will bear monitoring through the night for any tweaks to the forecast. Guidance continues to support a stripe of stronger winds aloft being mixed to the surface with precip across the plains and adjacent areas overnight, so the High Wind Warnings will continue as planned. Minor flooding has been reported in and around the Bears Paw and adjacent areas, where an areal flood advisory remains in effect into tomorrow. -AM && .SYNOPSIS... Widespread rain and snow will affect North Central MT through Wednesday, along with strong winds. Over Southwest MT, expect the precipitation to be more scattered. Temperatures remain below normal for the next few days, but do climb back up above normal over the weekend and into early next week, along with drier conditions. && .AVIATION... 519 PM MDT Tuesday May 7 2024 (08/00Z TAF Period) Low clouds, rain and snow, and gusty winds will all be a concern this TAF period, mainly across Central and North-central Montana through the day Wednesday. Snow looks to mix in at times at lower elevations, with prevailing snow groups included where confidence was highest. Expect mountain obscuration through the TAF period. -AM Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .HYDROLOGY... Heavy rainfall in the Bears Paw mountains will result in minor flooding on Beaver Creek and possibly Clear Creek. Flood highlights are in effect for portions of North Central MT. Brusda && .PREV DISCUSSION... /ISSUED 519 PM MDT Tue May 7 2024/ Key Points...Adjustments made to the high wind warning. Flood statements issued, but no changes to the winter weather statements. Tonight through Wednesday...Rain, heavy at times will affect North Central MT through Wednesday. There is an 80 percent chance of 1 inch of rainfall over much of North Central MT, with a 40 percent chance for 2 inches of liquid. One concern is how low will snow levels get. Snow levels are currently falling down to about 4000 feet, with the possibility of snow levels falling down to about 3500 feet. Thus snow is possible for the Great Falls area, while periods of snow fall around Belt, Geyser and Lewistown. With temperatures near freezing though, the snow will melt a bit at the lower elevations, limiting snow accumulations. However, some periods of heavier snowfall are possible at lower elevations, which will reduce visibility. In the mountains for elevations above 5000 feet, 6 to 12 inches of snowfall will be common, with 1 to 2 feet in the Kings Hill and Big Snowy areas. With a strong area of low pressure to our east, strong northwest winds will continue. Blizzard conditions are likely tonight and into Wednesday in the Kings Hill area. Elsewhere, the high wind warning was expanded along the I-15 corridor from Great Falls to Conrad as a period of strong winds are expected from now through late tonight. Below normal temperatures are expected through Wednesday as well. Thursday through Tuesday...The main storm system moves off to the east on Thursday, resulting in drier and warmer air moving in from the west. Expect a warming trend to begin on Friday and then continue through the weekend and into next week. Afternoon temperatures will be around 10 to 15 degrees above normal at times during this period. Weak upper level disturbances will try to move southeast from Canada into the northeast portions of the CWA by early next week. This could result in a few scattered showers or a thunderstorm, however much of the area will likely remain dry. Brusda && .PRELIMINARY POINT TEMPS/POPS... GTF 31 43 38 58 / 100 90 80 30 CTB 32 44 32 61 / 100 90 20 0 HLN 34 46 40 62 / 100 90 70 20 BZN 32 46 34 57 / 100 90 90 30 WYS 26 46 29 55 / 90 80 40 10 DLN 33 48 37 58 / 80 100 50 10 HVR 38 57 40 65 / 100 90 50 20 LWT 29 41 35 50 / 100 90 90 50 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 6 AM MDT Wednesday for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft- Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Fergus County below 4500ft-Hill County-Judith Basin County and Judith Gap-Northern Blaine County-Snowy and Judith Mountains-Western and Central Chouteau County. Winter Storm Warning until midnight MDT Wednesday night for Big Belt, Bridger and Castle Mountains-East Glacier Park Region- Gallatin and Madison County Mountains and Centennial Mountains- Snowy and Judith Mountains-Southern Rocky Mountain Front. Winter Weather Advisory until 6 AM MDT Wednesday for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty. Blizzard Warning until midnight MDT Wednesday night for Little Belt and Highwood Mountains. Winter Weather Advisory until noon MDT Wednesday for Cascade County below 5000ft-Fergus County below 4500ft-Judith Basin County and Judith Gap. Winter Weather Advisory until midnight MDT Wednesday night for Elkhorn and Boulder Mountains-Upper Blackfoot and MacDonald Pass. High Wind Warning until midnight MDT tonight for Big Belt, Bridger and Castle Mountains-Meagher County Valleys. && $$ http://www.weather.gov/greatfalls