FXUS63 KBIS 151130 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 630 AM CDT Wed Apr 15 2026 .KEY MESSAGES... - Patchy fog is over portions of south central into the James River Valley through the mid morning. - Warm and dry today, with highs this afternoon from the mid 60s to mid 70s. - Wide range in temperatures from northwest to southeast Thursday as a cold front pushes into the state. - Turning much colder with periods of rain and snow Thursday night through Friday, with medium to high chances for light accumulations of snow. - Well below normal temperatures Friday through Saturday, followed by a gradual warm-up into early next week. && .UPDATE... Issued at 630 AM CDT Wed Apr 15 2026 Generally quiet weather is found across western and central North Dakota this morning. Isolated showers from earlier overnight have generally diminished. In their wake, patchy fog has started to develop over portions of south central North Dakota into the James River Valley. An interrogation of BUFKIT soundings indicates that this fog is likely to be fairly shallow. Fog is generally expected to lift through the mid morning as the sun rises and the winds begin to pick up. Overall, the forecast remains on track. && .DISCUSSION... Issued at 305 AM CDT Wed Apr 15 2026 A weak 500mb shortwave traversing the northern Plains this morning has helped propagate light rainfall across portions of south central North Dakota, main where it overlaps a weak surface trough. These light showers will continue to exit to the east through the mid morning. Otherwise, patchy fog is possible across portions of eastern North Dakota into the James River Valley, as well as in the Turtle Mountains area. Lows are from the mid 30s east to upper 30s to lower 40s west and central. Near zonal to increasingly southwesterly flow is expected over the northern Plains today as a closed Pacific trough moves across the southern Canadian Prairies. With this pattern highs well above normal are expected this afternoon, from the mid 60s northwest to mid 70s southeast. Mainly clear skies are expected southwest and central through the morning and afternoon, though cloud cover will increase from northwest to Southeast through the late afternoon and evening ahead of an approach low complex associated with the aforementioned Pacific trough. Low chances for precpitation (10 to 30 percent) will develop across the far northwest and far north central this evening into early tonight, as a shortwave perturbation ejecting off this trough slides up the southwesterly flow pattern. Lows tonight are forecast from the upper 20s to lower 30s north, to lower to mid 40s south. By mid morning Thursday, the main wave of precpitation associated with the low complex is expected to start moving into the northwest, increasing to become likely (50 to 75 percent) across much of the southwest and central) late Thursday afternoon and evening. With the timing of the associated cold front delayed until later in the afternoon, highs on Thursday are expected to remain above normal in the 60s to mid 70s across the south, while dropping to well below normal in the mid 30s to lower 40s across the far north. With the lingering warmth across much of the forecast area, precpitation is expected to fall initially as rain, before transitioning overnight to a rain-snow mix, then all snow, as temperatures drop. With short term CAMs staring to contribute to the ensemble, the NBM has dialed into a slightly slower evolution of the system as whole, allowing for lightly accumulating snowfall to be possible across much of the forecast area Thursday night through Friday. The greatest source of uncertainty between ensemble members appears to be the relative strength of the trough as it crosses the northern Plains, which has ramification on overall QPF and thus overall snowfall accumulation. A slight majority of members (55 percent) favor a shallower trough, while would help limit snowfall across the southwest and south central to around a dusting at most, up to around an inch or so in the far north central. A minority cluster also exists (45 percent of members), which advertises a slightly deeper or close trough over the forecast area through early Friday morning. In this scenario, the potential for portions of central North Dakota as far south as I- 94 to exceed an inch of snowfall is higher (30 to 50 percent), while portions of the far north central could exceed 2 inches overall (15 to 30 percent chance). In either scenario, overall impacts due to snowfall are expected to be limited. Otherwise, breezy to windy conditions are expected both Thursday and Friday as the pressure gradient across the northern Plains tightens with the passage of the low complex, though the potential for any sort of wind headlines during this period remains very low. With the much cooler airmass over the northern Plains on Friday, well below seasonable normal highs in the 30s to lower 40s are forecast. Warming and dry weather is then expected through the weekend and into early next week as upper level ridging builds in across the region, with highs climbing back into the 60s and 70s by Monday. Long term deterministic models hint at the breakdown of the upper level ridge and a return to a more active pattern by the midweek as another deep pacific trough moves into the western CONUS, though there remains significant disagreement between ensemble members regarding timing. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 630 AM CDT Wed Apr 15 2026 Mainly VFR ceilings and visibility can be found to begin the 12Z TAF period. Patchy ground fog has developed across portions of south central North Dakota this morning, and has briefly impacted visibilities at KJMS. Have included a TEMPO group for 3SM vis at KJMS through the mid morning, as it is expected to be fairly variable. Later this evening, chances for light rain increases across the northwest, before diminishing overnight. Have included a PROB30 group for KXWA with this update. Tonight into into Thursday, low level wind shear is possible across portions of the west and south central. Have included mentions of such as KDIK and KBIS with this update. Confidence is too low to include mentions of KXWA. Light south winds around 5 to 10 knots this morning will turn west southwesterly through the afternoon, strengthening to around 10 to 15 knots and gusting as high as 20 knots across the north. Winds will then diminish through the evening, turning cyclonically around a low pressure center that will move across the forecast area overnight before reorganizing out of the northwest by the end of the TAF period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Adam DISCUSSION...Adam AVIATION...Adam