HydroClim Minnesota - January 2009

A monthly electronic newsletter summarizing Minnesota's climate conditions and the resulting impact on water resources. Distributed on the Wednesday following the first Monday of each month.

State Climatology Office - DNR Waters
compiled 1/7/2009

What happened in December:

December 2008 precipitation totals were well above average across Minnesota. The total water content of December's snowfalls topped historical averages by one-half inch to one and one-half inches in many locales.
[see: December 2008 Climate Summary Table]
December 2008 was marked by frequent, and often heavy, snowfall events. Many communities across the region reported over 30 inches of snowfall, setting new December records. The 33.5 inch December snowfall total in Fargo/Moorhead was the highest monthly snowfall total ever recorded for any month of the year. At International Falls, snow was observed on 28 of 31 days. Numerous daily snowfall records were set throughout the month at a variety of locations.
[see: Climate Journal | WeatherTalk]
Monthly mean temperatures for December 2008 were four to eight degrees below historical averages across Minnesota. It was the coldest December since 2000. Extreme temperature values for December ranged from a high of 48 degrees at Redwood Falls on the 3rd and at Winona on the 27th, to a low of -35 degrees Babbitt and Brimson (St. Louis County) on the 17th.
[see: December 2008 Climate Summary Table]

Where we stand now:

The snow depth map prepared on December 31 shows that the northern one-half of Minnesota has 12 or more inches of snow on the ground. Sections of west central, central, and northeastern Minnesota report more than 18 inches of snow cover. When compared with historical snow depths for the date, current snow depths in some west central and central Minnesota counties rank above the 95th percentile.
[see: Snow Depth Maps]
The U. S. Drought Monitor, released on December 31, classified many Minnesota counties in the D0 - Abnormally Dry category. Portions of east central and southeastern Minnesota were placed in the D1 - Moderate Drought classification. Precipitation during the last half of 2008 was five to eight inches short of average for many southeastern Minnesota communities. The U. S. Drought Monitor index is a blend of science and subjectivity where intensity categories are based on several indicators.
[see: U.S. Drought Monitor]
The U.S. Geological Survey reports that stream discharge values are high in the Red River basin. Stream flow measurements (where winter monitoring is possible) in the watershed are above the 90th percentile when compared with the historical distribution for this time of year.
[see: USGS Streamflow]
The Lake Superior water level is up 4 inches from last year at this time but remains below the long-term average. Levels on inland lakes in Minnesota's drought areas are low. In some cases, lake levels are similar to those observed during the droughts of 2006 and 2007.
[see: Corps of Engineers Great Lakes Water Levels]
In their final soil moisture summary of 2008, the Minnesota Agricultural Statistics Service reported that late-November topsoil moisture was 1% "Very Short", 6% "Short", 77% "Adequate", and 16% "Surplus". Surplus soil moisture conditions are found throughout the Red River basin. Subsoil moisture supplies were reported as 2% "Very Short", 16% "Short", 71% "Adequate", and 11% "Surplus". The focus of subsoil moisture deficits is on east central and southeast Minnesota. With the soils now frozen, substantial subsoil moisture recharge will not be possible until spring.
[see: Ag. Statistics Service Crop Progress and Condition]
Cold temperatures in December and early January deepened the frost layer in Minnesota's soils. Variable snow depths and a variety of ground covers lead to large variations in soil frost depths. Generally speaking, frost depths under sod range from a foot or less in southern Minnesota, to two feet in western and northern Minnesota.
[see: National Weather Service Frost Depth Data | Corps of Engineers Snow, Ice, Frost Data | MnDOT Road Frost Depths]
Minnesota's lakes are ice covered. Despite cold December temperatures, slush layers are found on some lakes with deep snow cover. As always, ice conditions are highly variable and those venturing onto water bodies should utilize caution and common sense.

Future prospects:

The January precipitation outlook favors above-normal conditions in southeastern Minnesota, and no significant tendencies away from climatological probabilities elsewhere in Minnesota. January precipitation normals range from near one-half inch in western Minnesota to just over one inch in eastern sections of the state. The median snow cover at the end of January ranges from near 5 inches in southwest Minnesota, to over 15 inches on the ground in northeastern Minnesota (greater than 24 inches in the Lake Superior highlands).
[see: Climate Prediction Center 30-day Outlook | January Precipitation Normal Map]
The January temperature outlook offers equal chances of below-normal, near-normal, or above-normal conditions. Historically, January is Minnesota's coldest month. Normal January high temperatures range the low-teens in the north, to near 20 in the south. Normal January lows range from near minus 10 degrees in the far north, to the single digits above zero in southern Minnesota.
[see: Climate Prediction Center 30-day Outlook | January Temperature Normal Map]
The 90-day precipitation outlook for January through March indicates no significant tendencies away from climatological probabilities across Minnesota. The January through March temperature projection tilts towards above-normal conditions in southeastern Minnesota, and no significant tendencies away from climatological probabilities elsewhere in 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 are part of the National Weather Service's Advanced Hydrologic Prediction Service (AHPS).
[see: National Weather Service River Forecast Center]

From the author:

Precipitation totals for the meteorological autumn (September through November) were far above long-term averages in the Red River basin. Precipitation values exceeded historical averages by two or more inches across most of the watershed. Both Fargo and Grand Forks set all-time autumn precipitation records for the three-month period. The present combination saturated soils, high stream base flows, and substantial snow cover, creates the possibility of spring flooding in this watershed.

Notes from around the state:

None

Upcoming dates of note:

January 15: National Weather Service releases 30/90 day temperature and precipitation outlooks
January 28: Interagency Spring Flood Outlook Coordination Meeting

Web sites featured in this edition:

http://climate.umn.edu - Minnesota Climatology Working Group, Minnesota DNR Waters and U of M Dept. of Soil, Water, and Climate
http://www.drought.unl.edu - National Drought Mitigation Center
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey
http://www.lre.usace.army.mil - US Army Corps of Engineers, Detroit District
http://www.nass.usda.gov - USDA, National Agricultural Statistics Service
http://www.crh.noaa.gov/ncrfc - National Weather Service, North Central River Forecast Center
http://www.mvp-wc.usace.army.mil - US Army Corps of Engineers, St. Paul District
http://www.dot.state.mn.us/mnroad - Minnesota Department of Transportation, Cold Weather Road Research
http://www.cpc.ncep.noaa.gov - National Weather Service, Climate Prediction Center

Acknowledgements

None

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