Rare northern Heat Advisory includes Duluth; Yellowstone fires sending smoke to Minnesota

Hot Front Arrives

Just when you were ready to write her off, the Summer of 2013 is back.

This week’s heat looks like the first pulse of what could be a sustained heat run. All indications are we may tack on another three to six days of 90 degree heat over the next two weeks, just in time for a free sauna-on-a-stick at the Great Minnesota Get Together.

Heat advisories for Duluth, Ely and International Falls? It seemed unthinkable two weeks ago.

Image: Duluth NWS

The heat is bubbling east front the Rockies, where persistent heat and dryness has sparked dozens of wildfires in recent weeks. Smoke is drifting overhead into Minnesota this week. More on the Yellowstone fires below.

Believe it or not, the Summer of 2013 is turning out warmer than average — and is trending dry as of late. The long range weather maps are hinting at a cold front that could break the heat spell about Sept. 4 — just after Labor Day.

Stay tuned.

9 days at or above 90 this year at MSP Airport

13 days = average

3 to 6 days of 90 degree heat likely in the next 2 weeks

Image: NOAA

Heat Wave 101

Back in the old days of weather, a “heat wave” was defined by National Weather Service as “3 or more consecutive days at or above 90 degrees.” We’ve learned a lot since then about how the body reacts to the combination of temperature and humidity. Dew point has become the term of art that best describes how comfortable you feel in any weather. If you add temps in the 90s on top of high dew points in the upper 60s and 70s, your body just can’t keep you cool for long.

Basically dew points over 60 degrees start adding to the “apparent temperature” your body feels. By the time dew points reach 70 degrees, it “feels” as much as 4 to 10+ degrees hotter as the temp rises. We call that the “heat index.”

Heat Index. Image: State University of New York at Albany.

Into the 90s

Temps already reached 90 degree in northern Minnesota Monday as heat spilled over an upper level ridge into northwest Minnesota. It looks like the heat may come in two waves. The first wave ramps up Tuesday and Wednesday. A cool front brings some relief and cooler weather for Thursday and Friday, then the heat returns with an even stronger surge of 90s by next weekend that could last well into nest week — and even Labor Day weekend.

Here’s the National Oceanic and Atmospheric Administration’s GFS model take from Weatherspark.

Image: Weatherspark

Severe Risk Wednesday?

A cool front cuts into the hot humid air Wednesday. That should be enough to trigger some strong to possibly severe storms. Here’s the risk area from NOAA’s SPC.

Image: NOAA

Smoky Skies

Where there’s heat, there’s fire. The western heatwave has been going on for weeks now and is finally spilling east into Minnesota. But fires have been active out west, sending smoke to Minnesota.

Image: NOAA

Numerous fires are burning in hot, dry windy weather in Idaho, Montana and Wyoming.

Image: USFS

The latest batch of fires is burning in Yellowstone National Park. Here’s the rundown on fires in the Park as of late Monday.

Image: National Park Service

NOAA’s satellite sensors can differentiate smoke from clouds. Heres’ NOAA’s smoke mapper which shows the western smoke plumes drifting over Minnesota.

Image: NOAA

Most of the smoke is elevated, but we’ll have to keep an eye on air quality in Minnesota  this week.

White tinted sky Monday afternoon. Image: Paul Huttner MPR News

Expect white tinted skies this week, and be on the lookout for some vivid reddish sunsets as smoke scatters out other light wavelengths and leaves the red tones for a pretty sunset. The moon may also take on colorful hues this week.