FXUS63 KFGF 182050 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 250 PM CST Wed Dec 18 2024 .KEY MESSAGES... - Winter storm warning from the Devils Lake Basin, and southeast into west central Minnesota. High confidence in a widespread 4 to 6 inches of snow, with a 20% chance for over 8 inches of snow within the warning. - Winter weather advisory for Sargent county as well as northwestern Minnesota for 2 to 4 inches of snow. - Widespread blizzard conditions are not expected (20% chance), with occasional or scattered whiteout conditions most likely to occur Thursday afternoon if at all. && .DISCUSSION... Issued at 250 PM CST Wed Dec 18 2024 ...Synopsis... Fast moving clipper trough will move into the Dakotas tonight and then off into MN/IA tomorrow, with a fairly broad swath of snow for our region. Northwesterly flow and surface high pressure set up for Friday and into the weekend, bringing fairly quiet conditions. Another cut off upper low will move quickly from the Dakotas to the Great Lakes on Monday, although there is still a lot of variation on exact track so impacts are uncertain. Quiet conditions and moderating temps look possible into the Christmas holiday. ...Winter storm warning tonight into Thursday... While the trough that is moving through the Northern Plains is fairly fast moving, it does bring a broad area of synoptic lift for an extended period of time tonight into tomorrow morning. Plenty of 850mb warm air advection, and while there is the potential for some mesoscale banding bringing even higher amounts, we could get 4 to 7 inches just from the main system. While winds are not particularly impressive at the start of the system, there will be a tight gradient and cold air advection tomorrow. There could be some blowing snow issues in addition to at least 4 inches of snow, mainly in the southern Red River Valley. With either the Grand Forks special 4 inches and wind or regular 6 inch criteria, think a large portion of our forecast area could see warning impacts. Have a warning roughly from Devils Lake to Hillsboro to Wadena where the heaviest QPF has been trending. ...Winter weather advisory... Less snow amounts down in Sargent county and less snow and less wind in northwestern MN near the Red Lakes and Lake of the Woods. Still at least minor winter impacts are likely so included the rest of our counties in an advisory. ...Blowing snow.... While winds will be gusting up into the 30 to 40 mph range at times by Thursday afternoon on the backside of the system, it does seem that the worst of the winds will be to our south and west. The best cold air advection and pressure rise/fall couplet is more over western and central Dakotas, and while winds will pick up and snow will blow, the widespread blizzard conditions that can occur up here are not expected. Instead chances are less than 20 percent of visibility less than half a mile, with only a few scattered to isolated occasions where whiteout conditions occur. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1228 PM CST Wed Dec 18 2024 Some lingering stratus continue to bring MVFR ceilings and even a few flurries to a few of the TAF sites for the next hour or so, then there should be a bit of a break with VFR for some of the afternoon and evening. Conditions will begin to deteriorate after 06Z as lower ceilings and snow move in starting in KDVL and moving east. Conditions should be down to IFR by morning. Visibility will be impacted by both falling and blowing snow, but at this point widespread below half mile does not look likely, so will keep vis 1/2SM at KFAR only and go a bit higher at the other airports. Winds will come around from the southeast to the east and then the northeast to due north at KDVL as the low pressure system moves through, with gusts above 25 kts at times by the end of the period. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...Winter Storm Warning from 9 PM this evening to 6 PM CST Thursday for NDZ006>008-014>016-024-026>030-038-039-049- 053-054. Winter Weather Advisory from midnight tonight to 6 PM CST Thursday for NDZ052. MN...Winter Storm Warning from 9 PM this evening to 6 PM CST Thursday for MNZ001>003-014-015-022-027-029>032-040. Winter Weather Advisory from midnight tonight to 6 PM CST Thursday for MNZ004>009-013-016-017-023-024-028. && $$ DISCUSSION...JR AVIATION...JR