TheClimateChanger

I wonder how much some of these extremes, even in otherwise cooler summers, were aided by extreme deforestation. I think we've added something like 50-100 million acres of forest since 1920.

Actually forecasting Code Purple for MSP metro area as well: MNZ041>045-047>070-073>078-082>085-091>093-122000- Anoka-Benton-Blue Earth-Brown-Carver-Chippewa-Chisago-Dakota- Douglas-Faribault-Freeborn-Goodhue-Hennepin-Isanti-Kanabec- Kandiyohi-Lac qui Parle-Le Sueur-Martin-McLeod-Meeker-Mille Lacs- Morrison-Nicollet-Pope-Ramsey-Redwood-Renville-Rice-Scott- Sherburne-Sibley-Stearns-Steele-Stevens-Swift-Todd-Waseca- Washington-Watonwan-Wright-Yellow Medicine- Including the Tribal Nations of Mille Lacs, Prairie Island, and Upper Sioux Including the cities of Albert Lea, Alexandria, Apple Valley, Blaine, Bloomington, Brooklyn Park, Buffalo, Burnsville, Eagan, Eden Prairie, Farmington, Hastings, Mankato, Maple Grove, Minneapolis, Minnetonka, Northfield, Plymouth, Prior Lake, Ramsey, Rogers, Rosemount, Roseville, Shakopee, St. Cloud, St. Louis Park, St. Paul, Stillwater, Waconia, White Bear Lake, and Woodbury 255 PM CDT Fri Jul 11 2025 ...AIR QUALITY ALERT IN EFFECT UNTIL 9 AM CDT MONDAY... * WHAT...The Minnesota Pollution Control Agency has issued an Air Quality Alert for fine particles pollution. The Air Quality Index (AQI) is expected to reach the Purple or Very Unhealthy category. * WHERE...Central and south central Minnesota. * WHEN...Until 9 AM CDT Monday. * IMPACTS...The risk of health effects is increased for everyone. * ADDITIONAL DETAILS...Heavy ground-level smoke from wildfires in central Canada moved into northwest Minnesota early Friday morning behind a cold front. This first band of smoke is currently impacting northern Minnesota as it moves east during the day Friday. Air quality will worsen across northeast Minnesota Friday evening as smoke arrives over the region. A second round of smoke will move into northwest Minnesota late Friday evening. This smoke will be more widespread as it moves southeast overnight, and by Saturday afternoon the entire state may be impacted. The heaviest smoke on Saturday will be across the northern half of the state. Air quality will begin to improve across western Minnesota Sunday morning as cleaner air moves in from the west. By Sunday evening, the smoke should be gone from most of the state. Another round of smoke is possible across far northern Minnesota Sunday night. PRECAUTIONARY/PREPAREDNESS ACTIONS... Sensitive groups, such as people with lung disease (including asthma), heart disease, and children and older adults, should avoid all physical activities outdoors. The general public should avoid prolonged or heavy exertion. Reduce or eliminate activities that contribute to air pollution, such as outdoor burning, and use of residential wood burning devices. Reduce vehicle trips and vehicle idling as much as possible. Keep windows closed overnight to prevent smoke from getting indoors. && For information on current air quality conditions in your area and to sign up for daily air quality forecasts and alert notifications by email, text message, phone, or the EPA AirNow mobile app, visit https://www.pca.state.mn.us/air-water-land- climate/current-air-quality-conditions. You can find additional information about health and air quality at https://www.pca.state.mn.us/air-water-land-climate/air-quality- and-health. $$ $$ Dunleavy

That's what I thought. I was surprised AI suggested a tendency towards colder winters when I prompted the question, citing colder winters in the 1940s-70s coinciding with a predominantly negative PDO?

Latest Air Quality Statement confirming likelihood of Code Purple conditions tomorrow over the Arrowhead of Minnesota. MNZ010>012-018>021-025-026-033>038-141400- Koochiching-North St. Louis-Northern Cook and Lake-North Itasca- Central St. Louis-Southern Lake-Southern Cook-North Cass- South Itasca-South Cass-Crow Wing-Northern Aitkin-South Aitkin- Carlton and South St. Louis-Pine- Including the cities of International Falls, Ely, Isabella, Bigfork, Hibbing, Two Harbors, Silver Bay, Grand Marais, Walker, Grand Rapids, Pine River, Brainerd, Hill City, Aitkin, Duluth, Pine City, and Hinckley 301 PM CDT Fri Jul 11 2025 ...AIR QUALITY ALERT IN EFFECT UNTIL 9 AM CDT MONDAY... * WHAT...The Minnesota Pollution Control Agency has issued an Air Quality Alert for fine particles pollution. The Air Quality Index (AQI) is expected to reach the Purple or Very Unhealthy category. * WHERE...North central and northeast Minnesota. * WHEN...Until 9 AM CDT Monday. * IMPACTS...The risk of health effects is increased for everyone. * ADDITIONAL DETAILS...Heavy ground-level smoke from wildfires in central Canada moved into northwest Minnesota early Friday morning behind a cold front. This first band of smoke is currently impacting northern Minnesota as it moves east during the day Friday. Air quality will worsen across northeast Minnesota Friday evening as smoke arrives over the region. A second round of smoke will move into northwest Minnesota late Friday evening. This smoke will be more widespread as it moves southeast overnight, and by Saturday afternoon the entire state may be impacted. The heaviest smoke on Saturday will be across the northern half of the state. Air quality will begin to improve across western Minnesota Sunday morning as cleaner air moves in from the west. By Sunday evening, the smoke should be gone from most of the state. Another round of smoke is possible across far northern Minnesota Sunday night. PRECAUTIONARY/PREPAREDNESS ACTIONS... Sensitive groups, such as people with lung disease (including asthma), heart disease, and children and older adults, should avoid all physical activities outdoors. The general public should avoid prolonged or heavy exertion. Reduce or eliminate activities that contribute to air pollution, such as outdoor burning, and use of residential wood burning devices. Reduce vehicle trips and vehicle idling as much as possible. Keep windows closed overnight to prevent smoke from getting indoors. && For information on current air quality conditions in your area and to sign up for daily air quality forecasts and alert notifications by email, text message, phone, or the EPA AirNow mobile app, visit https://www.pca.state.mn.us/air-water-land- climate/current-air- quality-conditions. You can find additional information about health and air quality at https://www.pca.state.mn.us/air-water-land-climate/air-quality- and-health. $$ Huyck

Looks like Central Park topped out at 97F. Much cooler than Boston with only 5 days in the 90s that month.

Dust storms were mostly from autumn through spring. I don't think there were many dust storms during the summer. A review of the Nebraska Monthly Weather Review for July 1936 reports only once instance of dust which lasted for a couple of hours ahead of an advancing cold front on the 19th. Looks like 1912 was an isolated stretch. 14 of the last 15 days of the month were below 80F in Boston that month, resulting in the 4th coldest stretch on record for that timeframe.

Can you speculate as to implications for winter in eastern North America?

On my mind for today:

Already seeing some of this activity in western Minnesota, with a number of these backyard Purple Air sensors registering AQIs in excess of 400. Comparing this to the modeled quantities for tomorrow, I wonder if we could see some AQI readings of 600-800 around Duluth, at least on some backyard sensors? Visibility has been as low as 1/2 mile in Grand Forks today. So that's what I mean when I say these visibility forecasts tend to be pretty conservative.

Tomorrow afternoon looks particularly rough for northeastern Minnesota, including Duluth and International Falls, with possible Code Purple conditions and visibilities potentially dropping below a mile in dense smoke. A bunch of active wildfires in western Ontario and eastern Manitoba (close source region) look to really get their act together tomorrow and throw off tons of smoke which may converge over the region.

Rarely see this visibility forecast register the smoke to this degree, but definitely going gung-ho on this in the western UP and northern Wisconsin, with widespread surface visibilities of 1-3 miles in dense smoke. Definitely something to keep an eye out for in Milwaukee, Chicago, Detroit, and Minneapolis. I see a lot of sunny forecasts, but those forecasts could be spoiled by this developing pall of smoke.

Definitely looks like some hazardous air quality will be working into the Midwest over the weekend. We can see by late Saturday night, things are looking particularly dicey over the Upper Peninsula of Michigan. This spills southward across Wisconsin and Michigan during the day on Sunday.

I would say that area is generally less prone to high heat (100s+) than the coastal plain. It does happen, but not very frequently. Regardless, my point is just that the reading is way above any surrounding observations in the immediate vicinity. Clearly, it was a hot day either way, but that reading is obviously inflated somewhat from either instrument error or poor siting/exposure.

I understand that, but that doesn't explain why the Martinsburg temperatures are consistently 5F warmer than surrounding towns in that era, including on the date it "hit" a state record of 112F. On the same date, it was 103F in Hagerstown (25-minute drive) and 105F in Kearnesyville (10-ish minute drive) with no appreciable elevation difference.