textproduct: Grand Forks

KEY MESSAGES

- Frost and freeze conditions are expected late tonight into Monday morning.

- Near critical to critical fire weather conditions are expected over parts of the region as temperatures increase next week.

UPDATE

Issued at 1248 PM CDT Sun May 10 2026

A Freeze Warning was issued for most of northwest MN where probabilities for widespread subfreezing temperatures exceed 80% (NBM/LREF), with lowest values in colder areas reaching the mid 20s. The position of the cold pool will be shifting east, however surface ridging will be centered over north central MN and calm winds/clear skies will set the stage for ideal radiational conditions in these areas.

A Frost Advisory was issued for eastern ND and the southern Red River Valley of west central MN. The recover of the air mass through the night occurs west to east, and as low pressure builds to the west southeast winds increase creating more uncertainty in widespread freeze impacts Monday morning and the potential for lowest temperatures in the west to actually fall shortly after midnight in the Devils Lake Basin. Even where winds increase, 2m temperatures should fall below 36F for at least a period of the morning hours and sheltered locations would likely fall to near 32F with frost impacts. In the northern Red River Valley of ND winds may be delayed long enough that subfreezing temperatures occur outside of just sheltered areas, and NBM shows a 50% chance for these conditions as far south as Grand Forks County, though the duration of these impacts if they occur would be limited as winds do increase after 4AM even in those areas.

UPDATE Issued at 913 AM CDT Sun May 10 2026

The Freeze Warning and Frost Advisories were allowed to expire as scheduled, with temperatures having improved to the upper 30s to upper 40s and continuing to increase. Another round of frost and freeze headlines may be needed for the late night/early morning period tonight/Monday morning. The coldest air aloft moves east through tonight, but much less cloud cover and generally light winds will still support 32-36F temps along and west of the Red River Valley (widespread freeze conditions more likely east). Where the cutoff for widespread freeze conditions (warning) versus advisory conditions will ultimately be dependent on wind speeds as flow shifts to the southeast and how much recovery of the air mass occurs before sunrise Monday. This will be assessed later this morning as the latest data comes in.

UPDATE Issued at 643 AM CDT Sun May 10 2026

Updated aviation discussion for 12z TAFs.

UPDATE Issued at 408 AM CDT Sun May 10 2026

Only minor changes to temps/RH grids the next 24 hours. Saturday saw dewpoint temps about 2-4 degree higher than HRRR had yesterday and RH barely reached near critical values. Today less wind aloft to mix and suspect overall a rather similar day today with lowest RH values holding 25 to 30 percent or just above the need for near critical fire weather conditions. Clouds are clearing out of NE ND and temps are falling blo freezing as of 08z and also in NW MN, so freezing warning looks fine. High pressure tonight will bring near calm wind to eastern fcst area and likely frost/freeze conditions esp east of the Red River this upcoming night. Rest of the week will see periods where RH values and winds reach a point where near critical to critical fire weather conditions may occur.

..Frost/freeze impacts Sunday and Monday mornings

Frost/freeze headlines issued for later tonight through Sunday Morning. Freeze headlines issued where ensemble probabilities for 32F or less temperatures were 80% or greater and frost advisories were 32-36F range is more likely. Urban heat island may result in marginal (32-34F) conditions in the immediate Grand Forks metro, however where this influence is less, temperatures are likely to drop below 32F during the early morning hours Saturday in Grand Forks and western Polk Counties.

There is still uncertainty in how much winds drop off (may hold around 10kt) in the Red River Valley (particularly in the south) due to the northerly component of the pressure gradient winds. There is also a signal for lingering pockets of mid level clouds, and the exact locations/coverage/timing in this type of pattern are often not well resolved. Current consensus favors southern part of our forecast area for these clouds, with more likely clearing in the north and northeast. These factors could complicate where widespread freeze conditions (32F or less) occur, and this factored into the decision on where headlines were drawn up. Even with clouds and winds around 10kt, low temperatures would be 36F or lower considering the cold nature of the air mass in place tonight. Where clearing/lighter winds occur within the frost advisory, impacts to sensitive vegetation would still be anticipated.

Sunday night/Monday AM frost/freeze potential: The pattern shift (building low pressure to the west/southwest) will result in moderating temperatures west to east and shifting low level flow to the southeast. The colder air mass will still remain in place across our eastern CWA and this is the type of set up where stronger gradient remains west allowing lighter winds to remain in place within the Red River Valley. There is a much better signal for clear skies Sunday night as well, so with better radiational conditions, it appears likely (greater than 60% probability) that freeze conditions will develop in northwest MN with a chance for frost/freeze within the Red River Valley. Chances for sub 36F temperatures are much lower due to this pattern shift west of the Red River Valley in ND Monday morning. We will ultimately need to consider additional frost/freeze headlines.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1248 PM CDT Sun May 10 2026

VFR conditions are expected through the TAF period across eastern ND and northwest MN. THere are some pockets of VFR CU (4700-7000ft alg) this afternoon that should clear around 00Z. Winds are generally from the northwest, but speeds are varying quit a bit as surface high pressure is building into the region and winds aloft decrease (5-15kt, with localized gusts around 20kt). Light winds are expected this evening as the sun sets and surface high pressure slides east into northern MN. Southeast winds develop late this evening/early overnight and increase through the Monday morning hours as low pressure builds to the west.

FGF WATCHES/WARNINGS/ADVISORIES

ND...Frost Advisory from 1 AM to 9 AM CDT Monday for NDZ006>008- 014>016-024-026>030-038-039-049-052>054. MN...Freeze Warning from 1 AM to 9 AM CDT Monday for MNZ001-002- 004>009-013>017-022>024-027-028-031-032. Frost Advisory from 1 AM to 9 AM CDT Monday for MNZ003-029-030- 040.