Wednesday deluge causes flooding; drier days ahead

Well, that was a deluge.

Heavy thunderstorms dumped 2 to 5 inches of rain on parts of Minnesota Wednesday. Deep tropical moisture (dew points in the 70s) produced prolific flooding downpours.

Flooding occurred in the Ely area.

The heavy downpours created instant waterfalls along Highway 61 and flooding around Grand Marais on the North Shore of Lake Superior.

Several inches of rainfall occurred across central and northeastern Minnesota.

Below are some select rainfall totals from Wednesday. These are preliminary reports and new reports will come in.

We’ll see a few stray thundershowers though Thursday morning in eastern Minnesota but the main flood and severe weather threat has shifted south and east of the Twin Cities.

Flooding and severe weather is still possible for southeast Minnesota including Interstate 90 and southeastern Minnesota into western Wisconsin.

Air quality alert through Friday

Another wave of smoke blows into Minnesota behind the cold front. The latest air quality alert covers most of Minnesota including the Twin Cities through Friday. Here are the details from the Minnesota Pollution Control Agency:

The Minnesota Pollution Control Agency (MPCA) has expanded the current air quality alert to include northern, central, south central, and southwest Minnesota. The alert runs until 11 p.m. on Friday, July 25. The affected area includes the Twin Cities metro area, Brainerd, Alexandria, Albert Lea, Marshall, Worthington, Hinckley, St. Cloud, Ortonville, Mankato, Bemidji, East Grand Forks, Moorhead, International Falls, Two Harbors, Hibbing, Ely, Duluth, Roseau, and the Tribal Nations of Upper Sioux, Mille Lacs, Prairie Island, Leech Lake, White Earth, Red Lake, Grand Portage, and Fond du Lac.

A band of heavy smoke from wildfires in Saskatchewan and Manitoba is moving south across northwest Minnesota on Wednesday. The smoke will remain over the northwest part of the state through the end of Wednesday, but by Thursday morning the smoke will reach southwest Minnesota. Smoke will also move into the northeast and central portions of the state Thursday morning, and by Thursday afternoon smoke will reach east central and south central Minnesota. Some uncertainty remains regarding how far south the ground-level smoke will reach by Friday morning, when winds are expected to become southerly and push the smoke back to the north. Air quality should improve gradually from south to north beginning Friday afternoon, with improvement in fine particle levels below the alert threshold expected by the end of Friday.

Fine particle levels are expected to reach the red air quality index (AQI) category, a level considered unhealthy for everyone, across northern and central Minnesota. This area includes Brainerd, Alexandria, Hinckley, Ortonville, Bemidji, East Grand Forks, Moorhead, International Falls, Two Harbors, Hibbing, Ely, Duluth, Roseau, and the Tribal Nations of Mille Lacs, Leech Lake, White Earth, Red Lake, Grand Portage, and Fond du Lac. In the red area, sensitive groups should avoid prolonged or heavy exertion and limit time spent outdoors. Everyone should limit prolonged or heavy exertion and time spent outdoors. Fine particle levels are expected to reach the orange AQI category, a level considered unhealthy for sensitive groups, across central, south central, and southwest Minnesota. This area includes the Twin Cities metro area, Albert Lea, Marshall, Worthington, St. Cloud, Mankato, and the Tribal Nations of Upper Sioux and Prairie Island. In the orange area, sensitive groups should limit prolonged or heavy exertion and time spent outdoors.

What this alert means

Air moves long distances and carries pollutants. During air quality alerts due to wildfires, the air is mixed with harmful smoke. Wildfire smoke spreads or lingers depending on the size of the fires, the wind, and the weather.

The air quality index (AQI) is color-coded. Air quality alerts are issued when the AQI is forecast to reach an unhealthy level, which includes forecasts in the orange, red, purple, and maroon categories. For a full description of each air quality category, visit airnow.gov.

Drier skies ahead

Sump pumps across Minnesota will appreciate a drier forecast ahead. Looks for more sunshine through some smoky skies into the weekend. Highs will dial back into the 80s south and 70s north for Thursday.

High will climb through the 80s through Saturday. By Sunday, the steamy tropical air mass returns with high around 90 in the south once again.

A cold front may bring storms by later Sunday. The European Centre for Medium-Range Weather Forecasts model brings much cooler air with highs in the 70s and dew points in the 50s by the middle of next week.

Stay tuned.