Bye Bye Summer of 2012; Temp crash today; 90s unlikely again

Cold front arrives! 20-30 degrees cooler next few days

Source: Twin Cities NWS

Scattered showers today in southern Minnesota

Source: Twin Cities NWS

95F at MSP Tuesday (62F this morning - a 33 degree temp plunge!)

31st day of 90+ heat in 2012 in the metro (most in 24 years)

96F record high Tuesday(set in 1931 & 1895)

74F average high for 9-11

+20 degrees vs. average Tuesday!

97F in New Ulm, Owatonna, Blaine & Eden Prairie

98F in Canby

99F in Madison

339 Wildfire "Incidents" in the USA according to Inciweb

Hottest year ever so far for the lower 48 USA

Cold front blowing in temps 20+ degrees cooler Wednesday

Cooler pattern emerging next 1-2 weeks across Minnesota?

Summer 2012: Out with a bang:

This is likely it for the blast furnace heat in the summer of 2012.

Temps soared to near 100 degrees under perfect conditions in southern Minnesota Tuesday. Late season sun, a gusty south wind and desert dry dew points combined to turbo-charge temps to record levels in Minnesota for September 11th.

The "thermal ridge" set up right over Minnesota Tuesday.

Source: University of Illinois

98 in Canby? 99 in Madison? On September 11th? That's the new weather math in Minnesota this year.

Desert dry air mass:

One reason temps soared Tuesday is the desert dry nature of the air mass sweeping into Minnesota this week. Dew points hung in the 40s Tuesday. Dry air is much easier to heat (and cool) than moist, humid air from the Gulf of Mexico

The air mass sweeping into Minnesota Wednesday is ridiculously dry for Minnesota. Dew points ran in the teens in Montana Tuesday...and 20s in North Dakota. That's desert air folks.

Source: University of Illinois

The air mass is feeding off drought in the northern Rockies and the Midwest. There's just no "moisture source" to absorb water vapor from.

Persistence is not just a made up weather word. Drought feeds drought.

With drought comes fires:

Check out the "fire incident map" from Inciweb. There are 339 "incidents" reported this week...most are active fires in the western USA.

Over 8 million acres have burned in the hot dry summer of 2012.

Pattern Change Ahead: Colder than average next 1-2 weeks?

There are strong signs that our weather pattern in Minnesota is about to change for the cooler...and stay there for a while.

The jet stream has been on vacation in northern Canada all summer long. A southward shift appears ready to drive the jet south toward Minnesota, and plunge a series of colder air masses southward in the next 2 weeks.

Source: NOAA/CPC

Highs will hover around 70 the rest of this week. After a milder weekend that may see an 80 degree reading in southern Minnesota by Sunday... a second, stronger cold front will dive south next week, and highs may struggle to reach the upper 60s in the metro, and 60 up north.

2012: Warmest year ever in the USA so far

The hit hits just keep on comin' for the USA this year.

Look at how far (+4F) above average the USA is running in 2012. The chart below from NOAA's NCDC is a great illustration of just how incredible 2012 heat run is in the USA.

Source: NOAA/NCDC

It's interesting to note that even though July 2012 was the hottest month ever on record in the USA, it was "just" the 4th hottest globally. Notice how the heat was focused on the USA and parts of eastern Europe and Russia, with cooler than average weather in the southern hemisphere.

Source: NOAA/NCDC

Even though the Twin Cities has logged 15 months in a row of above average temps now, it's not unthinkable to see a scenario where we flip into a cooler than average pattern for a few months.

I'm not holding my breath.

PH