HydroClim Minnesota for Early February 2017
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: February 2, 2017
What happened in January 2017:
- January 2017 monthly precipitation totals were near normal for many places in Minnesota. The exception was higher than normal precipitation totals in the southeast. Precipitation totals were one half to nearly two inches above normal in this area. In contrast, there were spots in southwest Minnesota that fell short of normal by a third of an inch. The largest precipitation event was on January 24-25, 2017 with heavy snow along I-90. Also noteworthy was a January 16, 2017 rain event that brought a half inch of precipitation over southeast Minnesota. This rain event glazed roads and walkways across the southeastern third of Minnesota. The preliminary statewide precipitation total was 1.28 inches or .49 inches above normal.
[see: January 2017 Precipitation Departure Map | January 2017 Climate Summary Table | January 2017 Percent of Normal Precipitation Map]
- Four significant rainfall or snowfall events occurred in Minnesota during January 2017. Other than the freezing rain event on the 16th and the heavy snow on January 24-25, there was a snowfall event on January 2-3 which brought heavy snow to northwest Minnesota, with freezing rain and drizzle in central Minnesota. On January 9-11 a series of snowfalls fell over a wide area of Minnesota and brought a general two to four inches for many locations. Snow fell again on January 24-25 with five to twelve inches of snow over far southern Minnesota, generally along and south of I-90. At the close of the month, there was more light snow and some freezing rain and drizzle on January 30-31 that brought several inches of snow to east central Minnesota and a mix of snow and freezing rain across the Twin Cities.
[see: Jan 2-3, 2017 Snow | Jan 9-11, 2017 Series of Snowfalls | M.L.K. Ice Storm: January 16, 2017 | Jan 24-25, 2017 Heavy Snow]
- Average monthly temperatures for January ranged from three to six degrees above normal for a preliminary state-wide average of 4.5 degrees above normal. The big story for the month temperature-wise was the prolonged January thaw that took place during the second half of the month. The peak of the thaw was from January 20-23 where overnight minimum temperatures also stayed above freezing for many areas in the central and south. This thaw eroded the snow pack across the central and south, and compacted the snow pack in the north. The warmest temperature for the state in January was near Forest Lake on the 20th with 49 degrees. Many areas in northeastern Minnesota also had high temperatures in the mid to upper 40's during the same period. January also had a brief flirtation of cold weather too, with the coldest minimum temperature for the month of -42 notched at Embarrass on January 13th. The warmth more than made up for the cold. January 2017 marked 17 months in a row of above normal monthly average temperatures for the Twin Cities. A stretch that is unmatched in the recorded record.
[see: January 2017 Climate Summary Table | January 2017 Departure from Normal Temperature Map | The Long January Thaw of 2017 | 17 Months and Counting]
Where we stand now:
- Snow depths across Minnesota range from areas of bare ground across parts of central, southwest and south central Minnesota, to a foot or more of snow on the ground in the northeast and far northwest. Snow depths of six to ten inches can also be found in southeast Minnesota centered near Rochester. The snow depth ranking is below historical averages across much of southern and central Minnesota, with some pockets of above average ranking over southeast and far northeast Minnesota.
[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 February 2 depicts no drought designation over Minnesota or any counties that border the state. The U.S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc.) are based on several indicators. The last time there were any drought indicators in Minnesota was on August 30, 2016.
[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. Most rivers and streams are now impacted by ice.
[see: USGS Stream Flow Conditions]
- In their final report of the 2016 growing season (November 28, 2016), 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.
[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 under sod are shallow for early February, generally around 12 inches or less at most Minnesota observing locations. The exception is in west central Minnesota, where the frost depth is around two feet.
[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 Under Sod]
- Minnesota lakes, rivers, and wetland complexes are ice covered. Warm November and December temperatures delayed ice formation. Lake ice formation was about a week later than the median in the south, and about two to three weeks late in the north. Lake and river ice is never completely safe. Some rivers had open flowing water in them during the month of January.
[see: DNR Conservation Officer Reports | Median Lake Ice-In Dates]
- The February precipitation outlook offers a tilt toward above-normal conditions in Minnesota. February is typically the driest month of the year. Precipitation normals range from near one-half inch of liquid equivalent in western Minnesota to just over three-quarter of an inch of precipitation in eastern sections of the state. The median snow depth at the end of February ranges from under five inches in southwest Minnesota to over 18 inches on the ground in northeastern Minnesota (greater than 30 inches in the Lake Superior highlands).
[see: Climate Prediction Center 30-day Outlook | February Precipitation Normal Map]
- The February temperature outlook leans towards above normal normal conditions across most of Minnesota. The exception is in the far north where there is equal chances for above, normal or below normal temperatures. Normal February high temperatures range from the low teens in the north to near 20 in the south early in the month, climbing to the mid-20s to low 30s by month's end. Normal February low temperatures range from near minus 10 degrees in the far north to the single digits above zero in southern Minnesota early in the month; ascending to the low single digits in the north, mid-teens in the south by the end of February.
[see: Climate Prediction Center 30-day Outlook | January Temperature Normal Map]
- The 90-day precipitation outlook for February through May indicates a tendency for above normal conditions across the entire state. The February through May temperature projection indicates a tilt towards below-normal temperatures, especially in central and northern Minnesota.
[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 the current weather conditions impacting prospects for spring snow melt flooding:
[see: National Weather Service - North Central River Forecast Center]
- present stream flows are 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 late autumn and into the winter.
- frost depths are shallow relative to historical values due to very warm early-winter temperatures and early deep snow cover in the north.
- snow depths are above the historical median for the date in far northwest Minnesota. Snow depth is below the median in central and most of southern Minnesota.
From the author:
- The cool winter that was in the 90 day outlook at the start of the winter season didn't exactly pan out. A mild December 2016 was followed by a very warm January 2017. Soils will remain moist across much of Minnesota as the frost thaws out of the ground this spring. If the weather regime continues to be wet, there could be a concern for warm season flooding.
Upcoming dates of note:
- February 16: National Weather Service releases 30/90 day temperature and precipitation outlooks
- Late-February: National Weather Service releases updated spring flood probabilistic outlooks
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Pete Boulay, DNR Climatologist