The Great Blue Norther of 11/11/11

The Great Blue Norther of 11/11/1911 was a cold snap that affected the central United States on Saturday, November 11, 1911. Many cities broke record highs, going into the 70s and 80s early that afternoon. By nightfall, cities were dealing with temperatures in the teens and single-digits on the Fahrenheit scale. This is the only day in many midwest cities' weather bureau jurisdictions where the record highs and lows were broken for the same day. Some cities experienced tornadoes on Saturday and a blizzard on Sunday.^[1] A blizzard even occurred within one hour after an F4 tornado hit Rock County, Wisconsin.

The main cause of such a dramatic cold snap was an extremely strong storm system separating warm, humid air from frigid, arctic air. Dramatic cold snaps tend to occur mostly in the month of November, though they can also come in February or March.^[2]

Kansas City

Temperatures in Kansas City had reached a record high of 76° F (24 °C) by late morning before the front moved through. As the cold front approached, the winds increased turning from southeast to northwest. By midnight, the temperature had dropped to 11° F (−11.7 °C), a 65 Fahrenheit degree (35 celsius degree) difference in 14 hours.^[2]

Springfield, Missouri

In Springfield, the temperature difference was even more extreme. Springfield was at 80 °F (27 °C) before the cold front moved through. Two hours later, the temperature was at 40 °F (4 °C) with winds blasting out of the northwest at 40 mph (65 km/h). By 7:00 P.M. Central Standard Time (01:00 UTC 12 November) the temperature had dropped a further 7 °F (3.9 °C), and by midnight, a record low of 13 °F (−11 °C) was established. It was the first time since records had been kept for Springfield when the record high and record low were broken in the same day. The freak temperature difference was also a record breaker: 67 °F (37 °C) in 10 hours.^[2]

Record highs and lows were established on the same day in Oklahoma City as well with a high of 83 °F (28 °C) and low of 17 °F (−8 °C); temperature difference: 66 °F (36 °C). This record still holds to this day.

Anomalous weather

The front produced severe weather and tornadoes across the upper Mississippi Valley, a blizzard in Ohio, and the windy conditions upon front passage caused a dust storm in Oklahoma. Nine tornadoes were reported in the states of Michigan, Illinois, Indiana, and Wisconsin. An F4 tornado hit in Rock County, Wisconsin killing 9 and injuring 50. Within an hour of the tornado, survivors were working in blizzard conditions and near zero temperatures to rescue people trapped in debris.^[2]

References

1. ^ "Waterloo Swept By Cyclone; Cutting Swath Through the Business Section of Town". The Fort Wayne Journal Gazette. Nov 12, 1911. http://www.gendisasters.com/data1/in/tornadoes/waterloo-tornado1911.htm. Retrieved November 11, 2011. 
2. ^ ^{a b c d} Albert, Drew (October 2003). "The Great "Blue Norther" of November 11, 1911". Ozarks Weather Observer. http://www.crh.noaa.gov/sgf/?n=great_blue_norther. Retrieved November 11, 2011.