FXUS63 KBIS 090639 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1239 AM CST Fri Feb 9 2024 .KEY MESSAGES... - Winter Weather Advisory continues over much of north central North Dakota through tonight, with additional accumulations generally under an inch. - Winds gusting up to 35 mph will result in patchy blowing snow, especially in open country and in association with falling snow. - A slight warming trend is forecast later this weekend through early next week, followed by another cooling trend during the middle to later portions of next week. Several waves may bring light precipitation chances (currently 20 percent chance or less) to the region next week. && .UPDATE... Issued at 1220 AM CST Fri Feb 9 2024 Going forecast remains in good shape, though some improvement is being noted in areas under winter weather advisory. Will let the advisory continue for now, but will be re-evaluating and possibly dropping it when the forecast package comes out later tonight. .UPDATE... Issued at 911 PM CST Thu Feb 8 2024 Surface observations and traffic webcams continue to improve across western North Dakota. Thus, we have elected to go ahead and cancel the Winter Weather Advisory here. We could still see some scattered flurries and some patchy blowing snow at times here overnight, but the main threats have subsided. Will keep the advisory going for the north central as we are still seeing some stronger radar returns here and traffic cams continue to suggest low visibility at times, especially in open areas. For this update, just tweaked precipitation chances a bit based on the latest observations and blended in the sensible weather fields to the going forecast. .UPDATE... Issued at 542 PM CST Thu Feb 8 2024 A broad area of light snow continues over much of western and central North Dakota early this evening. This activity should be on the downward trend over the next few hours as Storm Prediction Center mesoanalysis suggests that the strongest frontogenesis has moved well off to the east. The current light snow appears to mainly be driven by some weak cold air advection and broad synoptic forcing. This activity should continue to diminish as the upper wave moves out of the area. For this update, just refreshed some of the sensible weather fields overnight with the latest short term guidance and blended in the latest observations to the forecast. && .DISCUSSION... Issued at 230 PM CST Thu Feb 8 2024 Currently, large mid level low continues to spin over the Northern Plains and Upper Mississippi Valley, with two embedded circulation centers noted on latest radar and satellite imagery, one over central North Dakota and another over southern Minnesota. Wrap around precipitation continues to move mainly south/southeastward across western and central North Dakota, underneath a weak to moderate 600-500mb TROWAL wrapping around the backside of the upper low. Precipitation type is all snow for all but the James River Valley, where a mix continues to fall but should transition to all snow as well shortly. We're expecting another few hundredths up to under two tenths of an inch in QPF this afternoon and evening, with little additional amounts overnight through Friday morning, which generally results in another 1-2 inches at most of additional snowfall for the remainder of this storm event. In addition, winds gusting upwards to 35-40 mph may result in some blowing snow, especially in open country and especially in association with falling snow. Given it is still snowing and expected to snow into this evening (some areas perhaps seeing a period of enhanced snowfall), coupled with winds still gusty at times this evening resulting in some blowing snow, we've opted to leave the Winter Weather Advisory as is with this afternoon's forecast issuance. Expect the evening or mid shift will be trimming/removing counties as snow and any blowing snow issues end. Mid/upper level low lifts into the northwestern Great Lakes region this evening, then continues eastward Friday morning, ending snowfall across the region along with winds diminishing from west to east later tonight into the day Friday. An upper level trough over the Northern Rockies and an associated mid level wave may bring some lingering light snow to western ND on Friday, otherwise should be dry elsewhere by the afternoon. A progressive flow pattern continues to be depicted by model ensembles this weekend and through much of next week. Near normal temperatures on Friday and Saturday will slowly trend warmer/slightly above normal through early next week (Mon and Tue), before another cooling trend is favored through the remainder of next week as models attempt to amplify ridging over the western CONUS and try to bring a couple of stronger waves and associated cold FROPAs through our region. Uncertainty increases after Wednesday though with any given scenario, with 15-20 degree NBM temperature spreads between the 25th and 75th percentiles Fri and Sat (February 16-17th). Regarding precipitation chances, each wave will bring a chance of mainly snow given temperatures aloft, and amounts are expected to be light through midweek due to the progressive nature of the flow aloft. Timing and placement differences with each wave also remain high right now, so NBM chances are, not surprisingly, still 20 percent or less. Perhaps some better chances for accumulating snowfall mid to late week if the deterministic runs of the GFS and EC pan out, with each showing mid level wave/baroclinic zone interactions. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1235 AM CST Fri Feb 9 2024 Over western North Dakota, a mix of IFR and MVFR ceilings will continue through this morning, with mainly MVFR ceilings expected this afternoon. To the east, mainly MVFR ceilings expected. Areas of snow overnight may lead to localized MVFR/IFR visibility. The snow is expected to diminish Friday morning. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 AM CST early this morning for NDZ003>005-011>013-021. && $$ UPDATE...JJS DISCUSSION...NH AVIATION...JJS