“Fresh Front” arrives; Worst of summer heat & humidity over? 80% of USA now facing drought

84F high at MSP Airport Thursday

83F "average" high at MSP for July 26th

40s early Friday in northeast Minnesota towns like Embarrass & Biwabik

70s from the northern metro to Canada for highs Friday

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Source: Twin Cities NWS

50s dew points - roughly half as much water in the air vs. 24 hours ago

Worst of summer heat behind us now? - details below

80.08% of the USA (lower 48 states) either in drought or "abnormally dry"

A fresh breeze and 79 degrees Thursday afternoon from a North West view of Harrison's Bay, Lake Minnetonka

Source: http://www.therockwells.net/webcam/webcam.htm

"Fresh Front" arrives on schedule:

A fresh northwest breeze is sweeping heat and humidity south of Minnesota.

Dew points crashed as much as 15 degrees Thursday, (from the 70s to the upper 50s) as northwest winds blew in a welcome drying air mass from Canada.

Source: University of Illinois

The puff of cooler and much drier Canadian air will peak Friday and linger into Saturday. Temps will struggle to reach 80 in southern Minnesota Friday, with 70s from the north metro to Duluth and Ely.

A few scattered T-Showers will clip southern Minnesota (mostly southwest of the metro & Minnesota River), but overall this looks like a great summer weekend with mild temps and lower humidity.

Worst of summer heat behind us now?

I won't be making any "absolute declarations" about the next few weeks or month. As much as I wish I could, the state of the science of meteorology and the level of forecast model reliability just don't allow a credible meteorologist to do that.

That said, looking ahead at the maps into mid-August I do think the worst of summer heat & humidity are behind us now. What do I mean by that?

-The longer range map trends don't support an intense sustained "heat attack" like we saw in early July

-With lower sun angle, intensity and shorter daylight, it gets increasingly harder to reach 95 to 100+ degrees as we move into August.

Take a look at the distribution of 100 degree days in the metro from the MN Climate Working Group.

66 - Number of days we've hit 100 degrees in the metro (since 1873)

Only 6 days of 100 degree heat have occurred in August

Only 1 day of 100 degree heat has occurred after August 15th

(August 17, 1947)

As you can see, it's a lot tougher to hit the century mark in August than during the "peak solar intenisty" period of late June and July.

Here's the entire list of 100 degree days in the metro.

Below is a table of all the dates since 1873 of days where the temperature was 100 or more at the offical Twin Cities observing site.

Year Month Day Precip High Low Average

1883 7 1 0 100 72 86

1894 7 11 0 100 71 86

1894 7 26 0 100 75 88

1901 7 20 0 102 76 89

1901 7 23 0 101 74 88

1901 7 24 0 101 67 84

1913 8 15 0 100 74 87

1926 7 16 0 102 68 85

1931 6 28 0 102 82 92

1931 6 29 0 102 83 93

1931 6 30 0 100 82 91

1931 7 15 0 101 77 89

1931 7 16 0 100 80 90

1931 7 27 0 104 80 92

1931 9 10 0 104 75 90

1932 7 20 0.02 101 74 88

1933 6 19 0 100 75 88

1933 7 30 0 100 78 89

1934 5 31 0 106 75 91

1934 6 27 0 104 70 87

1934 7 21 0 105 73 89

1934 7 22 0 105 71 88

1934 7 23 0 105 80 93

1936 7 6 0 104 69 87

1936 7 7 0 101 80 91

1936 7 8 0 101 82 92

1936 7 10 0 106 80 93

1936 7 11 0 106 82 94

1936 7 12 0 106 83 95

1936 7 13 0 105 86 96

1936 7 14 0.04 108 72 90

1936 8 15 0.44 103 70 87

1937 7 10 0 100 76 88

1940 7 18 0 101 68 85

1940 7 19 0.02 100 76 88

1940 7 22 0 103 74 89

1940 7 23 0 103 75 89

1941 7 23 0 100 74 87

1941 7 24 0 104 76 90

1947 8 4 0 102 76 89

1947 8 5 0 100 78 89

1947 8 10 0 101 75 88

1947 8 17 0.28 100 72 86

1948 7 6 0 101 75 88

1949 7 3 0 100 79 90

1949 7 4 0 100 75 88

1955 7 26 0.08 100 73 87

1955 7 28 0 100 72 86

1956 6 13 0 100 77 89

1974 7 8 0 101 73 87

1976 7 13 0 100 69 85

1977 7 19 0 100 79 90

1980 7 11 0.3 100 72 86

1982 7 5 0 100 78 89

1985 6 8 0 102 64 83

1988 6 24 0 101 70 86

1988 7 15 0.06 102 79 91

1988 7 31 0 105 72 89

1988 8 1 0 101 74 88

1990 7 3 0 100 72 86

1995 7 13 0 101 75 88

2006 7 31 0.09 101 80 91

2011 6 7 0 103 78 91

2012 7 4 0 101 81 91

2012 7 6 0 102 78 84

The latest GFS runs going out about 2 weeks do show a return to some heat and humidity next week, but the latest trends include occasional showers/T-Storms & debris clouds which may keep us shy of 90 in the metro most days.

We've logged 24 days of 90+ at MSP Airport so far in 2012.

I'm reasonably certain we'll add a few more 90+ degree days in the metro this summer. My best guess? Probably another 4-7 days, but that's just a guess at this point. That would put us somewhere in the neighborhood of 28 to 31 days of 90 degree heat this summer. The last summer this "hot" was 5 years ago in 2007, when we endured 27 days at or above 90 in the metro.

At this point, I just don't see a return to a 1-2 week extended stretch of 95 to 100 degree heat for the metro ahead. Let's hope I'm in the ballpark on this one. My AC unit (and electric bill) need a break!

The "Great Drought of 2012"

We've covered the expanding drought this summer from different angles. But here's a number that adds shock value to the magnitude of the drought of 2012.

80.08%

That's the percentage of the USA (lower 48 states) either in "drought" or "abnormally dry" in this week's updated U.S. Drought Monitor.

Source: U.S. Drought Monitor/http://droughtmonitor.unl.edu/

Eastern Minnesota and northern Wisconsin remains an oasis in the expanding drought that has increased the grip to the west and south.

With corn and other grain prices setting new records, we'll all be feeling the Drought of 2012 in rising prices at the grocery store soon.

Want some good news? The overall weather pattern does look somewhat cooler and wetter for the nation's midsection in the next few weeks.

Source: NOAA/HPC

Let's hope that forecast pans out.

I'm away on a long planned vacation through next week. Craig & Bill will capably man the weather lab while I'm away. Let's hope they can bring milder weather and some more rain.

Have a great week!

PH