textproduct: Grand Forks

KEY MESSAGES

- Frost is forecast this morning in northwest Minnesota near Lake of the Woods to Red Lakes area.

- Showers and weak thunderstorms today. Additional chances for rain come Friday into the weekend.

..Rain chances ahead

Zonal flow aloft with entrance region of an upper jet will linger over our region through Wednesday, allowing a weak and progressive shortwave trough/upper ascent to migrate west to east across our area. While synoptic forcing is expected to be weak and moisture return meager, an uptick in instability is forecast to accompany this forcing/moisture. This will offer opportunity for thunderstorms of the weaker variety. Very little rainfall amounts are expected with this, despite the convective behavior.

On Friday, a rather robust banded-rain event is expected with strong forcing from frontogenesis fed by rich moisture and instability. Current guidance keeps majority of this rainfall (in excess of 3 inches) south of our area out of eastern SD into southern/central MN. However, given the majority of this forcing driven by mesoscale processes, confidence in location is not great. Thus, there is potential for this banded heavy rainfall to eek into locations near the SD border into west-central MN.

Into this weekend, a more consolidated shortwave trough is progged to translate across the Dakotas into Minnesota west to east. This will bring widespread rainfall chances. However, confidence is low in evolution of this particular wave given its time into the future nearing the predictability horizon. At this time, there is very little evidence to suggest amounts more than 1 inch from this particular wave.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 616 AM CDT Wed Sep 16 2026

VFR skies this morning with winds light and leading to patchy fog formation in area low spots but not currently impacts any terminal sites. Winds increasing from the south today to around 10kts. Biggest aviation hazard will be rain activity from 18z to 02z with each site seeing about a 4-5 hour window for rain and a low chance for thunder. Went with prob30 as chances are only 30-50% and didnt want a long tempo and feel this better conveys the expected scattered/transient nature of todays rain. With the rain CIGS will drop to about 6kft so staying MVFR but border on UND thresholds if the rain alone isnt enough to shut a few flyers down for the afternoon.

FGF WATCHES/WARNINGS/ADVISORIES

ND...None. MN...Frost Advisory until 8 AM CDT this morning for MNZ005-006-008- 009-016.