Roller coaster weekendA low pressure system brought strong southeastern winds to the state late Saturday, November 10th (Anniversary of the sinking of the Edmund Fitzgerald on Lake Superior in 1975), raising both temperatures and dewpoints to record-setting levels. MSP airport set a new high dewpoint record with a reading of 56 degrees F (breaking the form record of 55 degrees F in 1909) at 4:00 pm in the afternoon and also set a new high temperature record with a reading of 69 degrees F. It was the warmest November 10th since 1999. Several other Minnesota communities set record high temperatures that day as well including 75 degrees F at Rochester and Winnebago, 74 degrees F at Waseca, Fairmont (tied record), Albert Lea, and Wells, 72 degrees F at Zumbrota, Grand Meadow, and Preston, 71 degrees at Red Wing, 70 degrees F at Redwood Falls (tied record), 68 degrees F at Minnesota City, and 67 degrees F at La Crescent.
By evening thunderstorms had developed in many areas delivering up to 0.50 inches of rain in some places. Three rare November EF-0 tornadoes (winds 65-85 mph) were reported by the National Weather Service, one near Burnsville, another in Eagan, and a third around Mendota Heights. These tornadoes caused damage to many trees and also knocked down some power lines. In addition some straight line winds caused damage to trees as well. This incident was only the 4th time in Minnesota history that tornadoes have been documented in the month of November, and the 2nd latest fall date for such an occurrence. The others were: November 16, 1931, November 2, 1938, and November 1, 2000. You can read more here.
Following the passage of the cold front on Sunday, November 11, temperatures fell by over 40 degrees F in 24-hours (Rochester went from 75 F to 28 F) and many observers reported measurable snowfall, for the most part less than half an inch. Some observers reporting significant snowfall this week included 1 inch at International Falls and Grand Rapids, 1.5 inches at Cook, 1.7 inches at Moorhead, 2 inches at Lake Kabetogama, and 3.0 inches at Red Lake Falls. In the Twin Cities Metro Area, snow and ice caused many accidents on Monday morning (Nov 12).
On Monday (Nov 12) some observers reported daytime highs in the teens and twenties F, over 20 degrees F below normal. Fortunately the cold snap was short-lived and by Tuesday and Wednesday temperatures returned to near seasonal normals. Nevertheless the cold snap froze some soils down to 2-3 inches, and thin coats of ice began to form on many inland lakes. Friday morning brought the first single digit temperature readings of the fall season with 9 degrees F reported at Embarrass, Floodwood, Orr, Crane Lake, Cotton, and Hibbing.
Little change in drought statusDespite some reports of rain and snow this week, there is little change in Minnesota's drought status. Over 40 percent of the state's landscape remains in severe to extreme drought, with the most notable areas in northwestern and southwestern counties. Most observers reporting over an inch of precipitation so far this month are not in the drought-stricken areas of the state. These observers include Orr, Cook, Tower, Leech Lake, Silver Bay, Cloquet, La Crescent, and Caledonia. Unfortunately little moisture improvement is seen in the near future as the outlook through next week favors a warm and dry pattern across the state. You can read more about Minnesota's drought situation here.
Follow up on Kuehnast ProgramApproximately 250-300 people attended the Kuehnast Program's "mini-climate school" last Thursday (Nov 8) to hear presentations about Canada's climate, urban climates, and climate change implications for severe weather. The sessions were recorded and the archived versions are now available online for viewing by those who missed the program. You can find the recorded presentations here.
New Seasonal Climate OutlookNew seasonal climate outlooks were released by the NOAA Climate Prediction Center on Thursday this week. For the December through February period they call for below normal temperatures across the high plains and western Great Lakes states, including Minnesota. This is based on some dynamical models as well as a persistent negative phase in the Pacific Decadal Oscillation (PD)), a measure of disparity in the sea surface temperature of the north-central Pacific Ocean and the eastern sections of the north Pacific around the Aleutian Islands and the Gulf of Alaska that persists for decades. You can read more about this here.
The precipitation outlook for remains one of equal chances for above or below normal values covering the December through February period.
Weekly Weather potpourriNOAA announced this week that through new data sharing agreements it will have access to wind data collected by two of the nation's largest wind generator power producers in Oregon and Florida. These data will assist NOAA scientists in fine tuning forecast models. You can read more about this arrangement at the NOAA web site.
In South America where summer is approaching parts of southern Argentina reported high temperatures of 95-100 degrees F this week. These temperature values are on the order of 15 to 30 degrees F warmer than normal for this time of year.
A paper published in the current Bulletin of the American Meteorologist Society documents how the convective thunderstorm flash flooding in the high Himalayan desert during August of 2010 (8 inches or more of rainfall) was similar in dynamical characteristics to the famous flash floods in the USA at Big Thompson Canyon (CO) in 1976, and in the Black Hills of South Dakota in 1972. Satellite derived characteristics in these storms that are similar may help forecasters predict such storms in the future. You can read more here.
The World Weather Observations (WOW) web site operated by the United Kingdom Met Office is gearing up to expand their worldwide weather monitoring. You can view current observations from their network here.
MPR listener questionWas the interval between the Twin Cities tornado reports of Saturday night (Nov 10) and the measurement of subsequent snowfall in the area a record short one? Has this ever happened before?
Answer: The tornadoes occurred on Saturday night (Nov 10) near 11:00 pm, with a temperature of about 66 degrees F and a dewpoint of 55 degrees F. A little more than 12 hours later (11:40 am Sunday, Nov 11) the temperature was 30 degrees F with a dewpoint of 27 degrees F and a trace of snow was being reported. In another 24 hours 0.2 inches of snow was reported and the high and low temperature were 27 degrees F and 19 degrees F, respectively. Scanning the climate records for the Twin Cities I can find nothing analogous to this rapid shift from tornado occurrence to snowfall. The closest analogy for the Twin Cities is from November 16, 1931 when a tornado occurred near Maple Plain, and two days later the observer there reported a trace of snow. Elsewhere there are only two similar stories: On March 21, 1953 a tornado was reported near St Cloud, MN, and two days later on the 23rd St Cloud reported a low of 21 degree F with a trace of snow; and March 18, 1968 a tornado was reported near the Watonwan and Martin County border, followed three days later on the 21st by a trace of snowfall in the area.
MPR listener question
I wondered why the National Weather Service uses average temperatures from only 30 years to define what is "normal" for a location? Why not longer periods of time?
Answer: This standard period length for averaging climate measurements is mandated by the World Meteorological Organization (WMO) for all government weather services. It is the minimal period of time required to provide meaningful statistics, but more importantly it helps to maximize the number of climate stations for which averages can be computed. This is especially important for countries that do not have lengthy climate records. This standard helps scientists compare the averages from climate stations over a wide geographic area. In Minnesota we do have some community climate records that go back well over 100 years.
Twin Cities Almanac for November 16thThe average MSP high temperature for this date is 42 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 26 degrees F (plus or minus 10 degrees F standard deviation).
MSP Local Records for November 16thMSP weather records for this date include: highest daily maximum temperature of 68 degrees F in 1953; lowest daily maximum temperature of 17 degrees F in 1927; lowest daily minimum temperature of -2 F in 1933; highest daily minimum temperature of 50 F in 19138; and record precipitation of 1.27 inches in 1996; Record snowfall is 10.5 inches in 1909.
Average dew point for November 16th is 27 degrees F, with a maximum of 59 degrees F in 1931 and a minimum of -10 degrees F in 1959.
All-time state records for November 16thThe state record high temperature for this date is 75 degrees F at Marshall (Lyon County) in 1939, at Wheaton (Traverse County) in 1953, and at Marshall and Milan (Chippewa County) in 2001. The state record low temperature for this date is -27 degrees F at Big Falls (Koochiching County) in 1933. State record precipitation for this date is `4.10 inches at Two Harbors (Lake County) in 1909; and the state record snowfall for this date is 18.0 inches at Fairmont (Martin County) in 1909.
Past Weather Features:One of the snowiest mid-November periods in state history occurred over the 13th to the 16th in 1909. Many observers reported 6 to 12 inches, and some received up to 20 inches. Over 20 inches fell at Fosston and Fairmont.
November 16-17, 1911 brought 2 to 8 inches of snowfall to eastern Minnesota communities, including the Twin Cities area. Following the snowfall temperatures fell into the single digits F.
Well after dark, at 9:35 pm on November 16, 1931 a tornado touched down in Hennepin County near Maple Plain. It pack winds of 113-157 mph (F-2) and was on the ground for 5 miles. All barns and outbuildings of one farm were destroyed by these winds. This remains the latest fall season tornado ever reported in Minnesota.
November 16, 1933 brought arctic cold air to the state, as 36 communities saw the thermometer fall below 0 degrees F with daytime highs just in the teens F. Fortunately by month's end 50 degrees F returned to many places providing some relief from the cold.
Over November 15-16, 1939 a spell of Indian Summer weather prevailed as most observers reported daytime highs in the 60s F. Six communities topped out at 70 degrees F or higher. It was generally a warm, sunny, and dry (5th driest in state history) November that year.
November 15-17, 1953 was the warmest such period in state history. At least 36 Minnesota communities reported daytime highs of 70 degrees F or higher. It was the last gasp of mild fall weather as snow dominated the Minnesota landscape from November 20th to 30th. Some observers reported at least a trace of snowfall everyday during that interval.
A major winter storm crossed the state over November 15-17, 1996 bringing a mixture of rain. freezing rain, sleet, and snow. Some areas of northwestern Minnesota received over a foot of snow, while heavy rain fell in eastern sections of the state, setting record amounts in some cases. Many observers reported over a month's worth of precipitation, 2-3 inch amounts. Bruno, Santiago, and Wolf Ridge reported over 4 inches in one of the wettest periods in November history.
One of the mildest mid-November periods occurred over November 10-18, 2001 with many daytime temperature reaching the 60s F. Dew points were summer like as well ranging from the 50s to lower 60s F. Many golf course were open for business.