‘Ultra glorious’ summer; undulatus asperatus overhead

It's not your imagination. This was indeed one of the best summers on record in the Twin Cities. In fact it was an "ultra glorious" summer, according to the the State Climatology Office.

The State Climatology Office, a division of the Minnesota Department of Natural Resources, has tallied the final numbers for meteorological summer 2015.

The "Summer Glory Index" (SGI) for the months of June through August totals a whopping 2139.6 points this summer. That's the third highest SGI for the Twin Cities since dew point records began back in 1093. Only the summers of 1922 and 2008 boast a higher SGI.

The office describes any SGI vale of 2100 or greater as "ultra glorious." Only seven summers have achieved ultra glorious status since 1903.

Here's more on the incredible Summer of 2015 from the State Climatology Office.

If the 2015 Summer seemed unusually pleasant, that’s because it was!

Meteorological summer (June through August) ended with no major heat waves, little in the way of consistently unbearable humidity, and precipitation that was well-timed and well-proportioned. Indeed, it was a relatively comfortable, inoffensive summer.

Using the new Summer Glory Index (SGI), the summer of 2015 earned 2139.6 points, good enough for third place on the all-time list back to 1903. Only 1922 and 2008 earned higher scores.

The summer started off strong, with the finest June score on record, but then lost some ground in mid-summer, as warmer and more humid weather set in. The ranking dropped to #12 all-time on August 16th, but a return to stellar conditions during the last part of the month propelled summer 2015 back into the top 10, and finally back to #3 for the last two days of the month. The table below compares the final and monthly totals for 2015 with the best and worst on record:

The SGI assigns up to 10 points per day for favorable temperatures, dew points and rainfall.

Temperatures reached 90 degrees or higher only 4 days this summer at MSP Airport. The 30-year average is 11 days. Interestingly, overall monthly temperatures at Minneapolis-St. Paul International Airport this summer were almost exactly average.

• June +0.8 degrees

• July -0.4 degrees

• August -0.5 degrees

• Meteorological summer 2015 (-0.03 degrees)

The data shows one feature of the summer of 2015 was a remarkably stable temperature pattern with few extremes. Ultra glorious indeed.

Undulatus asperatus overhead

You may have noticed some funky looking wave clouds overhead. MPR News' Sam Choo captures this nice shot of undulates asperatus clouds over St. Paul Wednesday.

Undulates asperatus clouds are still an emerging area of research, but are believed to be caused by gravity waves as they roll through the atmosphere. Think of gravity waves as the ripples from a rock thrown into a pond.

Here's a good time lapse of undulates asperatus in action.

October preview 

Spotty showers linger into Thursday morning. Get ready for another October preview late Thursday and Friday as cooler air pours south. The warming trend kicks in for a spectacular fall weekend.