April climate summary, many records brokenApril 2013 was arguably the most anomalous month since March of 2012 when nearly 800 daily climate records were set (mostly for warmth). It was the third consecutive month that delivered colder than normal temperatures to the state. Mean monthly temperatures for April ranged from 6 to 12 degrees F colder than normal. Extremes for the month ranged from -14 degrees F at Embarrass on the 20th and 21st to 85 degrees F at St James on the 29th. On a statewide basis it was the 5th coldest April in state history. Many locations reported record-setting cold maximum temperatures or cold minimum temperatures over the 10th through the 14th and again over the 19th through the 24th. In total, over 240 new daily cold temperature records were set including a -11 degrees F reading at Babbitt and Tower, and -13 degrees F at Brimson on the 20th. The reading at Embarrass (-14 F) on the 21st was not only a new statewide record low for the date, but also the coldest temperature ever measured in Minnesota so late in the spring.
Except for western and northwestern counties, April 2013 delivered above normal precipitation to the state. On a statewide basis it was the 10th wettest April in state history. Many observers reported over 4 inches of precipitation. In the Twin Cities it was the 5th wettest April of all time (5.22 inches), and 2nd wettest at Rochester (6.79 inches). Elsewhere Babbitt reported the wettest ever April (5.36 inches), as did Jordan (6.05 inches), Faribault (6.48 inches), and Zumbro Falls (5.67 inches). Some observers in southeastern counties reported over 7 inches. Spring Grove (Houston County) set a new daily precipitation record on April 10th with 2.71 inches, as did La Crescent with 2.25 inches. Even more significant was the new statewide daily precipitation record set at Caledonia (Houston County) on the 10th as well with 2.80 inches (breaking the old record of 2.40 inches at Bricelyn in 1947). The frequency of precipitation was remarkable as well. Many observers reported measurable precipitation on 21-23 days during the month, and at Waseca they had 11 consecutive days with precipitation from the 5th to the 15th.
With the dominance of colder than normal temperatures much of April's precipitation fell as snow, and it was record setting at many locations. Isabella (Lake County) reported 25 inches of snowfall on April 19th breaking the old statewide record of 24 inches (St Cloud in 1893). Many other observers reported record-setting daily amounts of snowfall on 7th, 11th, 19th, and 23rd. The frequency of snowfall added up to record monthly snowfall totals for many Minnesota observers, including 55.9 inches at Park Lake (Carlton County), 55.6 inches at Island Lake (St Louis County), 50.8 inches at Duluth Airport, 47.0 inches at Babbitt, 46.5 inches at Isabella, 45.5 inches at Two Harbors, and 41 inches at Cloquet. Several other observers reported record monthly totals of snowfall as well, exceeding 20 and 30 inches in most cases (24.4 inches at St Cloud for example was a new April record total). Peak snow depth during the month was over 30 inches in northern parts of the state. With the thaw at the end of the month maple sap flow was going gang busters in northern forests and being collected by maple syrup producers.
May snowfall breaks records tooMay 1-2 brought snowfall to many parts of the state, especially southern counties. On Wednesday May 1st up to 2 inches of new snow was reported at New Ulm and Amboy. But the real intense snowfall began Wednesday night and lingered into Thursday (May 2nd) producing record amounts in southeastern Minnesota counties, where amounts of 6 to 14 inches were common. Some record daily amounts included 5.6 inches at Wabasha, 6.2 inches at Theilman, 6.4 inches at Lanesboro and Spring Valley, 7.0 inches at Albert Lea, 7.8 inches at Hastings, 8.4 inches at Zumbrota, 9.0 inches at Waseca and Grand Meadow, 10.0 inches at Austin, Owatonna, and Wells, 10.4 inches at Zumbro Falls, 14.0 inches at Rochester, 15.4 inches at Dodge Center, 17.5 inches at Goodhue, and 18 inches at Blooming Prairie. Many of these measurements were also all-time snowfall amounts for any day in May. The measurement at Dodge Center would be a new daily record snowfall amount for any NWS-COOP station during the month of May in Minnesota, surpassing 12 inches at St Cloud on May 17, 1890, at Windom on May 8, 1938, and at Leonard on May 3, 1954.
The storm presented a travel hazard and caused power outages in many places of southeastern Minnesota. There was also widespread reported tree damage. In addition Rochester, Faribault and Red Wing closed schools, giving students and teachers a rare May snow day. Even Friday morning (May 3rd) snow continued to fall in some southeastern Minnesota communities leaving additional measurable amounts including another 1.8 inches at Dodge Center, 3.9 inches at Wabasha, and 5.0 inches at Winona.
Snowfall in the east and southeast Metro area ranged from 3-5 inches, but most of the Metro Area was missed. The largest amount from a single May storm in the Twin Cities climate record (including Fort Snelling) is 3.0 inches which occurred in 1830, 1892, 1935, and 1946. The last year in that list, 1946 was especially notable because on June 1st of that year, Holman field in St Paul reported 38 degrees F with snow flurries from 2:24 am to 2:55 am, just barely into the month of June, but nevertheless the only documented observation of snow in the Twin Cities area during June. June of 1946 also brought snow flurries to Park Rapids, Willmar, and Gull Lake. More on historic May snowfalls can be found here.
With the addition of April and May snowfall amounts, the 2012-2013 snow season totals for some parts of Minnesota now rank among the top five for many communities. Some of these include 96.5 inches at Cloquet, 99.2 inches at Cass Lake, 112.5 inches at Babbitt, 120.5 inches at Chisholm, 124.4 inches at Wolf Ridge (Lake County), 129.4 inches at Duluth, and 143.5 inches at Isabella.
Ice-Out Dates Are LateIn contrast to 2012 (earliest ever ice-out dates for many lakes) many Minnesota lakes are still holding onto ice cover. The Freshwater Society declared ice-out on Lake Minnetonka on Thursday morning (May 2nd) this week, only the 5th time in history the lake has lost ice cover in May. The last time was 1965. Many northern lakes are still holding ice, including the Fish Hook chain of lakes near Park Rapids (Hubbard County) where the Governor's Fishing Opener is to take place May 10-12. Perhaps the warm-up in temperatures next week will assist the ice-out progress on Fish Hook Lake.
Weekly Weather potpourriHigh temperatures, low humidity and strong Santa Ana winds were contributing to a higher risk of wildfires in southern California this week, and indeed many fires broke out. The National Weather Service issued Red Flag Warnings, along with forecasts for near record-setting high temperatures in the mid 90s F for the Los Angeles Basin area. Winds on Thursday (May 2nd) afternoon were peaking in the 45 to 55 mph range and afternoon humidity ranged from the single digits to the teens.
A paper published recently by scientists from Manchester dissects strong mid-latitude cyclones to diagnose where what generates the strongest winds in the storm. They find that baroclinically strong descending air to the south or southeast of a low pressure system can become a so-called "sting jet" which is a band of strong winds that descends from aloft and reaches the surface bringing gale-force, destructive winds. This was their assessment of the storm structure associated with the famous October 1987 gale in the United Kingdom. You can read more about this paper here.
The EPA and NOAA were promoting Air Quality Awareness week as the summer season approaches and more people spend time outdoors. Their web site offers tips on air pollutant sources, air quality monitoring and forecasts, and how to keep the air in your local community cleaner. If you want to visit their web site go to...
The Cloud Appreciation Society cloud of the month for April depicts towering castles of cumulonimbus over Brazil, photographed by a pilot. You can view this photo and others at their web site.
MPR listener questionMy kids stayed home from school today (Thursday, May 2nd) in the Rochester area. Good thing too because the roads were miserable. I cannot remember ever having a snow day in the month of May. Has this ever happened?
Answer: The only other documented snow day I can find in May occurred in 1954 when many northeastern schools (Itasca, St Louis, Lake, and Cook Counties) closed school for two days as a result of 7-8 consecutive days of snowfall. In that case a foot to a foot and a half of snow accumulated and along with 40 mph winds made travel very difficult there. But my guess is that this may be the first time that southeastern Minnesota schools have closed for snow in May.
Twin Cities Almanac for May 3rdThe average MSP high temperature for this date is 65 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 43 degrees F (plus or minus 9 degrees F standard deviation).
MSP Local Records for May 3rdMSP weather records for this date include: highest daily maximum temperature of 93 degrees F in 1949; lowest daily maximum temperature of 35 degrees F in 1954; lowest daily minimum temperature of 18 F in 1967; highest daily minimum temperature of 65 F in 1959; and record precipitation of 1.72 inches in 1912; Record snowfall is 0.2 inches in 1954.
Average dew point for May 3rd is 39 degrees F, with a maximum of 66 degrees F in 1949 and a minimum of 12 degrees F in 2005.
All-time state records for May 3rdThe state record high temperature for this date is 97 degrees F at Bird Island (Renville County) and Willmar (Kandiyohi County) in 1949. The state record low temperature for this date is 6 degrees F at Crookston and Fosston (Polk County) in 1967. State record precipitation for this date is 4.00 inches at Albert Lea (Freeborn County) in 1902; and the state record snowfall for this date is 12.0 inches at Leonard (Clearwater County) in 1954.
Past Weather Features:May of 1902 started out very stormy with thunderstorms over the first four days of the month. Some record-setting daily rainfalls saturated farm fields and delayed planting. Many southern counties reported over 2 inches of rainfall over May 1-4, while Albert Lea reported 6.10 inches and Blooming Prairie 5.35 inches. For Caledonia, May of 1902 was the wettest ever with 11.13 inches of rainfall for the month.
At 7:00 pm on May 3, 1922 an F-2 tornado (winds 113-157 mph) moved 5 miles across the landscape in Dakota County. Near Northfield two barns were swept away and a home was seriously damaged. In addition a bus was overturned injuring two people.
May 3-4 of 1949 brought an early Heat Wave to Minnesota. It was clearly the warmest May 3rd in state history with over 25 communities reporting afternoon high temperatures in the 90s F. The month remained relatively warm and wet throughout getting crops off to a good start for the growing season.
May of 1954 brought snow to many parts of the state. In fact at Duluth and International Falls snowfall was reported on the first eight days of the month. Snowfall was several inches over May 1-4 and disrupted traffic, caused power outages, and even school closures in northeastern Minnesota where 10 to 18 inches of snow accumulated. Tower reported 10 inches of snowfall on the third.
A Cold Wave ushered in the month of May in 1967 with temperatures averaging 25 to 30 degrees colder than normal over the first three days of the month. Over 80 communities reported overnight lows in the teens F, while severe fell into the single digits. As far south as Luverne (Rock County) the temperature dipped to just 9 degrees F, an all-time record for so late in the spring.