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 8, 2018
What happened in February 2018:
- February monthly precipitation totals were generally above historical averages at most of Minnesota's reporting stations. The exceptions were in northwest and southwest parts of the state. Monthly precipitation totals were well above normal in northeast Minnesota.
[see: February 2018 Precipitation Total Map | February 2018 Precipitation Departure Map | February 2018 Climate Summary Table | February 2018 Percent of Normal Precipitation Map]
- A significant winter storm struck central and southern Minnesota on February 22-23, 2018. The heaviest snow fell over central Minnesota with Montevideo seeing eight inches and the Twin Cities metro area seeing four to six inches of snow.
Another heavy snowfall blanketed central Minnesota with a general six to eight inches. The Twin Cities International Airport saw six inches of snow.[see: Heavy Snow: February 22-23 and Heavy Snow: February 24]
- Statewide temperatures in February were below normal, with a preliminary average of 10.2 degrees or 6.6 degrees below normal. The last time the February average temperature was below normal was in 2015. February 2018 ranked as the 37th coldest out of 124 years. February 2017 was the 6th warmest on record with 24.0 degrees.
[see: Climate at Glance | February 2018 Climate Summary Table | 2018 February Departure from Normal Temperature Map]
Where we stand now:
- Snow Depths across Minnesota range from just an inch or so in far southeast Minnesota to nearly 30 inches along the Lake Superior highlands in northeast Minnesota. Snow depths are above historical medians for most of central and southern Minnesota with near the median in southern 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 March 8 shows an improvement of the drought conditions in west central Minnesota from the previous week. Abnormally Dry conditions persist in west central and north central Minnesota. A small area of Moderate Drought continues in Koochiching County, but has been reduced from last month. 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 flow measurements (where winter measurements are possible) are near normal when compared to historical medians for the date.
[see: USGS Stream Flow Conditions]
- In their final report of the 2017 growing season (November 27), the Agricultural Statistics Service reported that topsoil moisture across Minnesota was 0 percent Very Short, 3 percent Short, 85 percent Adequate, and 12 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. Soil moisture at Lamberton finished above the historical median for the final report for 2017 back on November 1.
[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 above normal for early March, ranging from about 18-31 inches under sod at most Minnesota observing locations, with some deeper frost noted in locations that had scant snow cover for much of the winter. Grand Forks was reporting a frost depth of 43 inches and Sandy Lake Dam had a frost depth of 48 inches. In general, two-inch soil temperatures under sod range from 24-32 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 wetlands are snow covered. Warmer daytime temperatures are causing slushy areas underneath the snow on lakes, but most lakes are still covered with a fresh white snow cover. As of this writing, a somewhat average lake ice-out is anticipated. Lake and river ice is never completely safe.
[see: DNR Conservation Officer Reports | Median Lake Ice-Out Dates]
- The March precipitation outlook has a tendency of above normal precipitation over the entire state. 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 equal chances for above, normal or below normal temperatures across the state, with perhaps a slight edge for above normal temperatures in the southeast. 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 for above normal conditions.
[see: Climate Prediction Center 90-day Outlook]
- The National Weather Service produces long range probabilistic river state and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. These products address both high flow and low flow probabilities. The risk of enhanced spring flooding will depend on the occurrence (or lack of) heavy rain events in March and April. Here are current conditions impacting prospects for spring snowmelt flooding:
- present streamflows are normal relative to historical flows for the date.
- soil profiles are moist due to above normal precipitation in 2017.
- frost depths are near historical averages.
- snow depths and precipitation are close to normal for the winter and well as the snowpack and snow water equivalent.
From the author:
- The winter storm of March 5-6 brought a general half to one inch of precipitation across much of central and southern Minnesota, along with four to eight inches of snow. Cross country skiing has been excellent in March so far.
- With the sounds of red-winged blackbirds in my neighborhood just north of St. Paul on March 8, there are at least some signs of spring. According to the National Phenology Network, spring has been arriving early to locations south of Minnesota. The spring leaf and bloom index showed that spring arrived nine days early at St. Louis, Missouri and six days early at Wichita, Kansas. Indications that this could be somewhat an early spring if the trend continues.
Upcoming dates of note:
- March 2: National Weather Service Weather issues Spring Flood Outlook with probabilistic products
- March 15: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Pete Boulay, DNR Climatologist