FXUS63 KBIS 250359 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 959 PM CST Sun Nov 24 2024 .KEY MESSAGES... - Below normal temperatures will continue through next week. The coldest period is forecast over the Thanksgiving Holiday weekend, when morning wind chill temperatures will approach 30 below zero some areas. - A clipper system could bring light accumulations across the state Tuesday and Wednesday. && .UPDATE... Issued at 957 PM CST Sun Nov 24 2024 For late evening update main change was to add some isolated snow showers around Lake Sakakawea. Satellite shows cloud cover coming off the lake towards the southeast, and would not be surprised if some flakes are coming out of that. Will keep the possibility for light snow going through the overnight. UPDATE Issued at 626 PM CST Sun Nov 24 2024 Light snow continues to shift to the east of the area, with a few flakes lingering over eastern Dickey County. This will continue to move out over the next few hours. With that said, have increased clouds in the forecast over much of the area. Although clearing is developing, especially over the northwest, clouds still remain overcast over southeastern portions of the area. && .DISCUSSION... Issued at 228 PM CST Sun Nov 24 2024 An upper level low continues to move across southern Saskatchewan into southern Manitoba placing western North Dakota in the dry slot. Dry air wrapping around the upper low and subsidence aloft is mixing breezy conditions across the west. Dry air continues to drive the low stratus over central North Dakota eastward. Dry air intrusion has also ended freezing drizzle across much of central North Dakota while freezing drizzle continues eastern North Dakota and portions of the James River Valley, but will clear up later this evening. Some snow continues to move up from the southwest and could clip the James River Valley this evening. Overnight lows are forecast to drop down near 0 to the single digits. This due to strong surface high pressure and a strong Arctic airmass settling in the region. Temperatures are already in the low teens in the northwest as surface high pressure builds. Tomorrow, high temperatures may only climb out into the lower teens north to 20s south. The upper level pattern will lock into northwesterly flow as high pressure builds out over Western CONUS and low pressure stalls out over the Great Lakes. This will keep the upper level pattern over the Northern Plains in northwesterly flow. Thus, opening the door for a few weak upper level waves resulting in light snow throughout the week. The first of these waves is forecast to move in late Tuesday into Wednesday. The 25th to 75th snow forecast currently has 1 to 2 inches possible with locally higher amounts possible. Another weaker wave could move through the region Thanksgiving. Temperatures are forecast to remain in the teens up north and the 20s down south through the week. These below normal temperatures will linger through weekend as another burst of cold air move trough the region and the end of the week. This will lead to cold temperatures persisting around Thanksgiving. Low temperatures are forecast to drop down to 15 to 20 below up north to 5 below to 0 down south Friday morning. Wind chills could reach 30 below across the state. These cold temperatures will persist into the weekend. The pattern begins to look a bit more uncertain next week. If the upper level ridge shifts further east that would result in "warmer" temperatures or if the ridge remains out west colder temperatures will persist. The warmer solution has about 65 percent chance while the colder solution is around 35 percent chance. This is reflected in the NBM 25th-75th which has over a 30 degree spreed for high temperatures early next week. Even though there is a 30 degree spread, the 25th percentile trends warmer at the beginning of next week showing a rebound in temperatures. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 626 PM CST Sun Nov 24 2024 Localized IFR with areas of MVFR ceilings will continue over parts of south central North Dakota including the KJMS terminal this evening, with conditions improving overnight. Elsewhere, most locations will remain VFR, though localized MVFR cloud cover may pass by from time to time overnight. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...JJS DISCUSSION...Johnson AVIATION...JJS