A monthly electronic newsletter summarizing Minnesota's climate conditions and the resulting impact on water resources. Distributed on the first Thursday of the month.
State Climatology Office - DNR Division of Ecological and Water Resources, St. Paul
distributed: March 3, 2017
What happened in February 2017:
- February monthly precipitation totals were near to above historical averages at most of Minnesota's reporting stations. Monthly precipitation totals were somewhat below normal in portions of southwest and central Minnesota.
[see: February 2017 Precipitation Total Map | February 2017 Precipitation Departure Map | February 2017 Climate Summary Table | February 2017 Percent of Normal Precipitation Map]
- A significant winter storm and blizzard struck south central and southeast Minnesota on February 23-24, 2017. The heaviest snow fell over southeastern Minnesota and avoided the Twin Cities. The highest snow totals were from Owatonna in Steele County to Lake City in Wabasha County where 12 to 15 inches fell.
[see: Winter Storm and Blizzard: February 23-24]
- Average monthly temperatures for February were well above historical averages at all Minnesota reporting stations. It was Minnesota's tenth consecutive month of above-normal monthly temperatures, and for the Twin Cities, the eighteenth month in a row of above normal temperatures. Extremes for February ranged from a high of 67 degrees F at Redwood Falls Airport (Redwood County) on the 17th, to a low of -24 degrees F at Hallock (Kittson County) on the 8th. Temperatures soared into the 50s and 60s across Minnesota on February 17-22, breaking temperature records for the date. February 2016 wound up in the top ten warmest Februaries on record are various locations in the state. February 2017 ranked the 3rd warmest in St. Cloud, the 7th warmest in the Twin Cities. Duluth was the 9th warmest and International Falls was the 11th warmest. The preliminary statewide average temperature for February was nine degrees above normal.
[see: 18 Straight Warm Months | February 17-22, 2017 Heat Wave | February 2017 Climate Summary Table | 2017 February Departure from Normal Temperature Map]
Where we stand now:
- Snow depths across Minnesota range from zero across large sections of central and western Minnesota, to over 24 inches along the Lake Superior highlands in northeast Minnesota. Snow depths are below historical medians for the date nearly everywhere in Minnesota with the exception of far northeast Minnesota where snow cover is somewhat above median. For places in west central Minnesota, having zero snow depth at the beginning of March is a rare occurance and is about a one in 25 to a one in 50 year event. There are even a few places in Becker County where March 2, 2017 is near a record minimum for snow depth.
[see: Weekly Snow Depth and Ranking Maps | NWS Snow Depth Estimation Map | Midwest Regional Climate Center Snow Depth Map]
- The U. S. Drought Monitor map released on March 3 shows no areas in Minnesota in a dryness category. The U.S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc.) are based on several indicators.
[see: Drought Conditions Overview]
- The U.S. Geological Survey reports that stream discharge values (where winter measurements are possible) are much above historical medians for the date on most Minnesota rivers and in some places, the highest readings measured for the date.
[see: USGS Stream Flow Conditions]
- In their final report of the 2016 growing season (November 28), the Agricultural Statistics Service reported that topsoil moisture across Minnesota was 0 percent Very Short, 1 percent Short, 75 percent Adequate, and 24 percent Surplus. History has shown that soil moisture conditions observed in the late autumn are indicative of conditions to be expected when the soil thaws.
[see: Agricultural Statistics Service Crop Progress and Condition | U. of M. Southwest Research & Outreach Center (Lamberton) | U. of M. Southern Research & Outreach Center (Waseca)]
- Soil frost depths are shallow for early March, less than 19 inches under sod at most Minnesota observing locations, much shallower in many locales. Historically, frost depth reaches maximum extent in late February or early March. One interesting phenomena has been observerd at several locations in late February and early March with the top few inches frozen, then several inches thawed, and then a deeper lens of frost. In general, suface soil temperatures are near 32 degrees.
[see: Corps of Engineers Snow, Ice, Frost Data | National Weather Service Frost Depth Data | MnDOT Road Frost Depths | University of Minnesota - St. Paul Campus Soil Temperatures]
- Minnesota's lakes and wetland complexes are ice covered. Some smaller ponds and lakes with moving water or an aeration system are partially open. Warm February temperatures led to sloppy ice conditions on many lakes. As of this writing, an early lake ice-out is anticipated. Lake and river ice is never completely safe.
[see: DNR Conservation Officer Reports | Earliest Lake Ice-Out Dates on Record]
- The March precipitation outlook has a tendency of above normal precipitation over northern Minnesota and offers equal chances of below-normal, near-normal, or above-normal conditions across the rest of Minnesota. Historically, average March precipitation totals range from near three-quarters of an inch in northwestern Minnesota to around two inches in southern sections of the state. March is a transition month when cold, dry continental air masses are gradually replaced by warmer, moister air on a more frequent basis. This is demonstrated by the fact that March's normal precipitation is 50 percent higher than February's normal precipitation, the greatest percentage increase between any two successive months.
[see: Climate Prediction Center 30-day Outlook | March Precipitation Normal Map]
- The March temperature outlook leans towards above-normal conditions across southern and central Minnesota and equal chances for above, normal or below normal temperatures in the north. Normal March high temperatures climb from near 30 degrees early in the month to the low to mid-40s by month's end. Normal March lows begin the month in the single digits above zero in the far north and mid-teens in the south. By late March, normal lows are in the low 20s in the north, near 30 in the south.
[see: Climate Prediction Center 30-day Outlook | March Temperature Normal Map]
- The 90-day precipitation outlook for March through May has a tilt to above normal conditions, especially across the north.
[see: Climate Prediction Center 90-day Outlook]
- The National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. These products address both high flow and low flow probabilities. Here are current conditions impacting prospects for spring snowmelt flooding:
- present streamflows are high to very high relative to historical flows for the date
- soil profiles are moist to saturated in most areas due to excessive precipitation in 2016,
- the high stream discharge and moist soils are due to high precipitation totals in the autumn and the winter along with early snow melt,
- frost depths are shallow relative to historical values due to mild winter temperatures,
- snow depths are well below the historical median for the date in most Minnesota locales, with the exception of the far northwest and parts of the southeast
From the author:
- Indications that this will be an early spring continue with reports of the nationwide spring leaf index being two to three weeks ahead of normal.
Upcoming dates of note:
- March 2: National Weather Service Weather issues Spring Flood Outlook with probabilistic products
- March 16: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Pete Boulay, DNR Climatologist