


Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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798 FXUS63 KBIS 281146 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 646 AM CDT Sat Jun 28 2025 .KEY MESSAGES... - Scattered showers and an occasional thunderstorm will continue across some parts of western and central North Dakota throughout the day today, but severe weather is very unlikely. - Highs in the 80s today, with humid conditions persisting in south central and eastern North Dakota. - Much quieter weather is expected Sunday into Tuesday, with slightly cooler and less humid conditions. && .UPDATE... Issued at 645 AM CDT Sat Jun 28 2025 Scattered showers with occasional lightning continue to drift eastward across mainly southern North Dakota early this morning. Also have seen signs of what is mostly patchy ground fog from around Tioga and Stanley to Max, and back southwest from Beulah/Hazen to Hettinger. The fog has become locally dense from around Mott to New Leipzig, but the most recent webcam images from that area are already starting to show signs of improvement. Overall, the forecast remains in good shape. && .DISCUSSION... Issued at 422 AM CDT Sat Jun 28 2025 Active southwest flow aloft remains over the Northern Plains early this morning. The remnants of last night`s severe storms are now long gone into Minnesota, but showers and weaker thunderstorms have reignited along the low level jet along the ND/SD border. A few stronger cells had been embedded in this activity earlier in the night, but observed lightning activity has greatly diminished since 3 AM CDT. A surface trough/frontal boundary from northeast to southwest North Dakota is forecast to slowly meander eastward through today. Little temperature difference is expected on either side of the boundary, with highs expected to reach the 80s. But southeast of the boundary will remain quite humid with dewpoints in the 60s. Convergence along the surface boundary looks weak, and deterministic guidance shows little to no cyclonic vorticity embedded in the mid to upper level flow this afternoon. Therefore, in spite of as much as 2500 J/kg CAPE and 40 kts deep layer shear southeast of the surface boundary, we do not expect forcing to be strong enough to overcome another capping inversion this afternoon and evening. The 00Z HREF confirms this thinking with only a 10 percent neighborhood probability of UH exceeding 75 m2/s2, which is entirely being contributed by the FV3 CAM that has a known high-bias for intense convection. We do expect pockets of showers and perhaps the occasional sub-severe storm to persist across the state this morning, with activity likely to wane through the afternoon as forcing steadily weakens. The one possible failure mode for a severe storm-free forecast for today would be a remnant outflow boundary supplying sufficient lift to force air parcels above the LFC, but such a boundary does not appear to exist in our forecast area early this morning. Later tonight, a few CAMs bring convection originating from the Black Hills and high plains of southeast Montana/northeast Wyoming into far southern parts of the state, but by that time there is not expected to be enough instability/buoyancy to support any strong to severe convection. A mid level shortwave is forecast to deepen over southern Manitoba on Sunday and dig into the Upper Midwest Sunday night into Monday. This could result in 1) isolated showers and perhaps a thunderstorm across northern North Dakota Sunday afternoon and evening, 2) breezy northwest winds north and east of the Missouri River Sunday and Monday, and 3) slightly cooler and not as humid conditions with highs Sunday and Monday closer to around 75 to 80. On Monday, there is timing uncertainty on the transition of northwest flow aloft from cyclonic to anticyclonic. If it stays cyclonic through Monday afternoon, which would likely only be for the eastern half of the state, diurnally driven showers and thunderstorms could develop. Ensembles present a variety of forecast outcomes for Tuesday into the holiday weekend, but the general theme is for northwest flow aloft with a western CONUS ridge possibly shifting into the Plains Wednesday or Thursday, followed by a more amplified and chaotic quasi-zonal flow. The NBM favors highs in the 80s for Tuesday and beyond, but could see a day or two in the lower to mid 90s depending on the timing and strength of the thermal ridge axis moving off the Rockies. Low to medium chances for showers and storms are found throughout the extended forecast beginning Tuesday night. Prospects for severe thunderstorms next week remain low, but are non-zero. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 645 AM CDT Sat Jun 28 2025 Patchy fog has developed across parts of western North Dakota early this morning, especially southeast of KDIK. TAF sites are unlikely to be affected, and the fog should quickly dissipate an hour or two after sunrise. Widely scattered showers and perhaps a few thunderstorms will remain possible across western and central North Dakota through this morning, with any lingering activity likely diminishing through the afternoon. Severe weather is no longer expected, but brief downpours and gusty winds are possible with any storm that develops. VFR conditions are otherwise expected today. Western and northern North Dakota will see west to northwest winds increase to 10-20 kts this afternoon, with lighter winds elsewhere. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hollan DISCUSSION...Hollan AVIATION...Hollan