textproduct: Grand Forks

KEY MESSAGES

- Fog lingering tonight before clearing out behind a cold front.

- Winter impacts expected Sunday into Monday with accumulating snow greater than 2" and blowing snow leading to widespread travel impacts.

- Below average temperatures continue.

..Synopsis

Sunday's system can already be noted across Montana and southern Alberta in water vapor imagery with the baroclinic zone along the international border. As the low drops southeast through the Dakotas and into southern Minnesota by Monday morning strong northerly flow will develop at the surface with moderate FGEN along and east of the Red River Valley to the north of the low acting as an inverted trough shutting off precip to the west of wherever the FGEN sets up. With this there are a few scenarios but we boil it down into two primary ones down below. As the low moves southeast into Iowa on Monday the pressure gradient weakens and blowing snow comes to an end with cold conditions on the back side. Beyond the cold a few shortwaves amid the northwest flow could bring shots of light snow and blowing/drifting snow but more tranquil (and less foggy) weather expected.

- Ongoing Fog

Advection fog remains across the region albeit not contiguous for the most part as warm air traverses the saturated snowpack with a warm nose aloft and thick stratus preventing any good surface heating and thus keeping us in this December wintry soup. At least with it being below freezing its freezing fog so all the trees are nice and pretty (we'll ignore that its also making the roads icy per DOT reports)... gotta find a bright side I tell myself.

- Sunday/Monday Snow

Scenario 1) where the strongest FGEN lines up from Detroit Lakes to Roseau or east of there. Scenario 2) where it lines up slight east of there bringing heavier snowfall to the valley (greater than 2"). In both cases to the east of the FGEN expect 2-4" with locally higher totals approaching 6-7" (10% chance). However in the western case strong winds/gusts of 45mph or greater are likely to overlap with areas that see 2" leading to a 60% chance for blizzard conditions if snow is no longer falling and a 100% chance for blizzard conditions if snow remains falling during strong winds (even 1" over 6 hours would satisfy this falling snow criteria). As of now the eastern scenario where strong winds do not overlap with 2" of snow in the Valley seems to be the favored outcome by guidance but there has been a rapid shift from almost nothing to now a possible blizzard in the last 36 hours so not selling the house on what the current guidance shows as things remain fluid. So as a floor this feels like a solid advisory event between a widespread 1" (valley) to 3-5" in the MN northwoods with isolated to scattered blowing snow (dependent upon how much new snow falls in a given location). As a ceiling one could see this going as severe as a Blizzard in the RRV (2" of new snow in combination with wind gusts > 45mph) and a winter storm warning in the MN northwoods with 4-7" of new snow and scattered blowing snow in more open areas. As such with the wide uncertainty and potential ceiling have gone with a winter storm warning for the entire Red River Valley (blizzard potential) and the Minnesota northwoods (>6" of snow possible). West of the Red River Valley even at the ceiling this looks to be an advisory with up to 1-2" of new snow and patchy blowing snow. Timing Sunday morning (midnight to 6am) to Monday morning (6am)

- Monday

Other than the recovery from whatever this event ends up being there is high confidence in cold temps/wind chills. Widespread wind chills in the -20s for all with more northern areas still favored to fall into the -30s meeting cold weather advisory thresholds. Should be only for a short duration (6pm Sunday to noon Monday) but in combination with the winter storm could pose an extra level of impact to travelers that are unprepared. Highs through the period otherwise look seasonal if not slightly below average with all days failing to reach into the 20s (minus Tuesday which cold reach near freezing)

- Tuesday

A weak clipper looks to move through Tuesday night into Wednesday bringing a quick shot of light snow 1-2" (didnt look much at this with tomorrow's system the primary focus of this forecast period) and some patchy blowing snow likely Wednesday morning as temps fall behind the attendant cold front.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 528 PM CST Sat Dec 27 2025

IFR to LIFR conditions will persist for the TAF period. Visibility from fog should improve over the next several hours to above 1 mile. A winter system is approaching from the west and is likely to impact all TAF sites to some extent. The further west you go, the bulk of impacts will be tied to falling snow and will have shorter duration impacts (namely DVL). As you get to FAR/GFK, snow and blowing snow is likely to develop tomorrow, with prevailing 1/2SM expected and the potential for brief reductions to 1/4SM. As you go east towards TVF/BJI, periodic bursts of heavier snowfall rates may bring visibility down to 1/4SM at times, but should remain predominately 1/2SM to 2SM.

Conditions will continue like this until the end of the TAF period, with improvements possible at DVL once falling snow ends.

FGF WATCHES/WARNINGS/ADVISORIES

ND...Dense Fog Advisory until midnight CST tonight for NDZ014>016- 024-026>030-038-039-049-052>054. Winter Storm Watch from 3 AM CST Sunday through late Sunday night for NDZ008-016-027-029-030-039-053. MN...Dense Fog Advisory until midnight CST tonight for MNZ001>003- 007-029>031-040. Winter Storm Watch from 3 AM CST Sunday through late Sunday night for MNZ001>004-007-029-030-040. Winter Storm Watch from Sunday morning through late Sunday night for MNZ005-006-008-009-013>017-022>024-027-028-031- 032.