Record setting inversion


Upper air sounding from Twin Cities NWS weather balloon launch last night at 6pm from Chanhassen. Temperature was a remarkable 58 degrees at 4,600 feet!

Our persistent temperature inversion this week is now a record setter.

Last night at 6pm, the NWS at Chanhassen released the twice daily weather balloon into the air to record weather data from the surface to the upper atmosphere. The data that beamed back opened some eyes at your local NWS.

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At the top of our strong temperature inversion 4,600 feet above the ground, the temperature was a balmy 58 degrees. Not only was this the warmest reading at this level (850 millibars) in the country last night, it was the warmest 850mb temperature ever recorded in any wintertime (Dec-Feb) sounding in Twin Cities' history!

This shows the strength of our temperature inversion this week in Minnesota, and why it's so difficult to forecast high temperatures with inversions present over snow cover in winter. Without our deep snow cover and with more sunshine we would have likely reached at least 50 degrees Wednesday in the metro.


So at least you can brag to your friends in warm places that the Twin Cities had the warmest temperature in the nation last night at 4,600 feet.

Category 3 Snowstorm in December:

I haven't talked about this much, but the NWS is using a relatively new scale to measure the effect of snowstorms in the eastern USA. It's called NESIS, and it's designed to measure the impact of major snowfalls. The scale, similar to the Saffir Simpson Hurricane Scale, ranks storms from Category 1 (Notable) to Category 5 (Extreme).


The December 18-20 storm that dumped heavy snow on the Washington D.C. area was rated a Category 3 storm. It's good to know somebody is keeping track. Now maybe we should start naming our snowstorms in Minnesota. Perhaps we could call our recent Christmas snowstorm "St. Nick?"