Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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018 FXUS63 KBIS 301959 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 259 PM CDT Thu May 30 2024 .KEY MESSAGES... - Showers and a few thunderstorms will exit James River Valley this afternoon. An isolated shower or thunderstorm may move into the northwest late this afternoon. - Seasonably cool temperatures Friday with areas of frost possible southwest Friday morning, then scattered afternoon showers and thunderstorms. - Dry Saturday then chances for showers and thunderstorms return later Saturday night through early next week. && .DISCUSSION... Issued at 233 PM CDT Thu May 30 2024 A blocking upper level pattern will keep an upper level low situated over the central Canadian Prairie Provinces through the weekend. A combination of shortwaves rotating around this low, and impulses coming off the Pacific, tracking across the Northern Rockies and below the Canadian low will influence the weather over our area through the weekend. This low eventually gets pushed east as a stronger wave coming off the Pacific moves into the Region early to mid next week. Currently, showers and a few thunderstorms are lingering over the far southern James River Valley but should exit the area this afternoon. This activity is situated along a warm front/trough that is currently exiting the JRV. Breezy westerly winds behind this front have developed over most of western and central North Dakota. A trailing cold front will sweep through the area later this afternoon and tonight. There may be a few showers trying to move into western ND late this afternoon/early this evening, but with very dry air southwest, the potential for shower activity will likely be limited to the west central/northwest and any thunderstorm activity should be limited to the far northwest corner. Late tonight and early Friday the focus shifts to temperatures. Current forecast trends clear out much of western and central ND tonight. By 12Z Friday, surface high pressure is situated over western SD with mid and high level clouds beginning to work back into western ND from the southwest. However, very dry air is situated over the area overnight. The NAEFS SA table shows a signal for dry PWATs over western ND. IF winds drop off tonight, which it looks like they may in the southwest, and skies remain clear, we could see some temperatures in the middle 30s southwest, resulting in Frost. Given our normally cool areas west of the Missouri River extend north and east to the Beulah/Hazen area and towards eastern Lake Sakakawea, the area of mid 30s could extend even farther north and east than we are currently advertising. NBM 10th percentile was only depicting some upper 30s and no frost, so we combined some MOS based guidance to trend temperatures down a bit over the southwest. MET/MAV guidance for Hettinger is 34. There is the potential that mid level clouds could move into the area, keeping temperatures from dropping into the 30s at all. Will hedge towards the cool side and pass along to the evening shift. Potentially we could see a frost advisory if ideal conditions are met. After a cool start Friday, diurnal heating, combined with another upper level impulse will fire afternoon showers and thunderstroms. The lack of heating is expected to keep the severe threat to a minimum and SPC is currently carrying a general thunderstorm risk and this looks reasonable. Saturday will bring mostly sunny skies with warmer temperatures. Highs should be mainly in the 70s statewide. Late Saturday night and Sunday, an impulse emanating from the Pacific will move into the area bringing another round of showers and thunderstorms, with a stronger wave moving into the Region early next week. There is some some indication that the far southeast could see a few stronger storms on Sunday but this remains quite a ways out. Still something to monitor as we head into the weekend. Uncertainty in the deterministic models and ensembles increases as we head into next week, but the pattern will likely remain active through at least Monday and Tuesday. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 1152 AM CDT Thu May 30 2024 Scattered shower and thunderstorm activity should be exiting the James River Valley early in the forecast period and may need to carry a VCTS/VCSH at KJMS very early on in the period. Otherwise precipitation has exited the forecast area. Additional isolated shower activity may move into the northwest late this afternoon but for now will not include a VCSH. Westerly surface winds today generally 15 to 25 knots. Winds will diminish to 5-10 knots this evening and generally southwest to west, and will begin to pick up late in the morning Friday. Once activity exits the KJMS area VFR conditions are expected across the forecast area through the period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...TWH AVIATION...TWH