Arnold, MN Weather

Key Messages

- Above normal temperatures through the work week

- Next chance of rain is Friday afternoon into Saturday

- More seasonable temperatures return next week

Discussion

Issued at 204 AM CDT Tue Oct 20 2026

A stable omega blocking pattern becomes firmly established across the central United States today, keeping our region under the control of an upper-level ridge. Kept the trend for slightly increased daily maximum temperatures going each day through Thursday. Plentiful sunshine will prevail alongside light southerly breezes. Meanwhile, local lake breezes will develop along the Lake Superior shoreline during the afternoon, keeping coastal areas noticeably cooler and closer to seasonal norms along the North Shore, while interior communities continue to experience unseasonable autumn warmth. The lake breeze is expected to move the most inland on Tuesday and Thursday. There will be a slight ripple in the blocking pattern for tomorrow as a weak cold front and upper level trough crosses the Upper Midwest. Not expecting these features to amount too much aside from a slight increase in clouds for Tuesday night through Wednesday morning before dry air aloft overspreads the region again.

Changes begin on Friday as the persistent omega ridge starts to break down. A closed upper-level low over the Great Basin will eject northeastward toward the Upper Midwest. Cloud cover will steadily increase throughout the day. Rain chances are still on track to arrive Friday afternoon into Saturday, and confidence is higher that precipitation will occur over that time period even if scattered as models are becoming more constant with that timing. Because temperatures ahead of the system remain unseasonably mild, all precipitation will fall strictly as liquid rain.

Scattered light rain showers will linger across the area through Saturday as the trough axis and associated cold front push across the Upper Great Lakes. By Monday, dry conditions return as high pressure rebuilds behind the departing system, accompanied by clearing skies. A significant air mass change behind the cold front will drop temperatures back toward seasonal values for late October.

Aviation

Issued at 621 AM CDT Tue Oct 20 2026

Surface high pressure is moving off to the east through the forecast period with southerly flow returning to the Northland. Expect mostly sunny skies and VFR conditions through the period. A cold front will be advancing out of the northwest tomorrow morning. No precipitation expected with this feature but upper level clouds will increase and winds will switch to out of the north behind the boundary.

Marine

Issued at 204 AM CDT Tue Oct 20 2026

Quiet weather pattern through the work week with winds staying less than 15 knots and waves remaining less than 3ft through the period. Strong southerly flow returns Friday night and may warrant a Small Craft Advisory.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.