HydroClim Minnesota - December 2007

A monthly electronic newsletter summarizing Minnesota 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 12/5/2007

WHAT HAPPENED IN NOVEMBER

- November 2007 precipitation totals were well below historical averages across Minnesota. Monthly precipitation totals ranged from near zero to just over one half of an inch. Precipitation for the month fell short of normal by one to two inches.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/drynov2007.htm )
- other than the exceptional dryness, November 2007 was an unremarkable month climatologically. Mother Nature saved her best work for the start of the meteorological winter, December 1. Nearly every Minnesota county received some snow on December 1, with some locations in northeastern Minnesota reporting over 12 inches of snow. Another snowstorm followed shortly behind, dropping three to nine of snow across much of central and northern Minnesota on December 4.
(see: http://climate.umn.edu/doc/Journal/snow071201.htm )
- monthly mean temperatures for November 2007 were somewhat warm in Minnesota, finishing one to four degrees above historical averages. Extreme values for November ranged from a high of 66 degrees for multiple locations in west central and southwest Minnesota on the 12th, to a low of minus 15 degrees at Hallock (Kittson County) on the 27th. The temperature dropped below zero for the first time of the season on November 22 in a few north central and northeastern Minnesota locations.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )


WHERE WE STAND NOW

-  the snow depth map to be prepared on Thursday, December 6 will show that all Minnesota counties have at least three inches of snow cover. Many central and northern Minnesota locations report more than 12 inches of snow on the ground. An early and enduring snow cover has been rare in Minnesota recently. The last time the state was broadly covered by this much snow, this early in the winter, was late-November and early-December of 1996.
(see: http://climate.umn.edu/doc/snowmap.htm )
- the U. S. Drought Monitor, released on November 29, places a relatively small area of west central and central Minnesota in the "Moderate Drought" category. Portions of northwestern and north central Minnesota remain designated as "Abnormally Dry". This is an acknowledgement of some lingering precipitation deficits. All other Minnesota locales are deemed to be free of drought conditions. The U. S. Drought Monitor index is a blend of science and subjectivity where intensity categories are based on several indicators.
(see: http://www.drought.unl.edu/dm/monitor.html )
- the U.S. Geological Survey reports that stream discharge values, for observation points where winter measurements are possible, are near to above the median for the date in most locations.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd )
- water levels remain below average on some Minnesota lakes. However, the wet autumn caused most Minnesota lakes to rebound to within a range of levels commonly found at this time of year. In some cases, lake levels soared past mid-range in October and are now well above average. The Lake Superior water level is up five inches from last year at this time. While the Lake Superior water level is no longer near the all-time seasonal low, it remains well below the long-term average.
(see: http://www.lre.usace.army.mil/greatlakes/hh/greatlakeswaterlevels/waterlevelforecasts/weeklygreatlakeswaterlevels/ , http://www.dnr.state.mn.us/lakefind/ , http://lwcb.ca/waterflowdata.html )
- in their final report of 2007, the Minnesota Agricultural Statistics Service reported that despite the dry November weather, mid-November topsoil moisture was "Adequate" across 83% of Minnesota's landscape. This is a substantial improvement from conditions reported in early August when nearly 85% of the state reported less than adequate soil moisture conditions.
(see: http://www.nass.usda.gov/Statistics_by_State/Minnesota/Publications/Crop_Progress_&_Condition/index.asp )
- cold temperatures in late November and early December solidly froze Minnesota's soils. Frost depths under sod range from three to twelve inches across Minnesota. If the early and heavy snow cover endures, Minnesotans can expect relatively shallow frost depths throughout the winter.
(see: http://climate.umn.edu/doc/observatory.htm , http://www.mvp-wc.usace.army.mil/bulletins/winter.html )
- nearly all of Minnesota's lakes are now ice covered. Freeze-up occurred during the last few days of November and first few days of December. The ice was relatively thin just before being covered with snow from the December 1 storm. Therefore, ice thickness is highly variable and ice safety is marginal in places. Those venturing onto the state's water bodies should utilize caution and common sense.
(see: http://www.dnr.state.mn.us/enforcement/co_report/index.html )


FUTURE PROSPECTS

- the December precipitation outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. December precipitation normals range from around one-half inch in western Minnesota to over one and one-quarter inches in eastern sections of the state. The median snow cover at the end of December ranges from over 10 inches on the ground in northeastern Minnesota (20 inches in the Lake Superior highlands), to under 5 inches in southwestern counties.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/precip/precip_norm_12.htm )
- the December temperature outlook tilts towards below-normal conditions, especially in northeastern Minnesota. Normal December high temperatures are in the mid 20's to near 30 to start the month, dropping to the mid-teens to near 20 by month's end. Normal lows are around 10 degrees early in the month, falling to the mid-single digits above and below zero by late December.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/temp_norm_adj/temp_norm_adj_12.htm )
- the 90-day precipitation outlook for December through February indicates no significant tendencies away from climatological probabilities across Minnesota. The December through February temperature projection tilts towards above-normal conditions in nearly all Minnesota counties.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php )
- 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: http://www.crh.noaa.gov/ncrfc/ )


NOTES FROM THE AUTHOR

- none

NOTES FROM AROUND THE STATE

- none

UPCOMING DATES OF NOTE

- December 20: National Weather Service releases 30/90 day temperature and precipitation outlooks


WEB SITES FEATURED IN THIS EDITION

http://climate.umn.edu - Minnesota Climatology Working Group, Minnesota DNR Waters and University of Minnesota Department 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 - Detroit District, US Army Corps of Engineers
http://mndnr.gov/waters - Minnesota DNR Waters
http://lwcb.ca - Lake of the Woods Control Board
http://www.nass.usda.gov - USDA, National Agricultural Statistics Service
http://www2.mvr.usace.army.mil/WaterControl/new/layout.cfm - St. Paul District, US Army Corps of Engineers
http://mndnr.gov/enforcement - Minnesota DNR Enforcement
http://www.cpc.ncep.noaa.gov - Climate Prediction Center, National Weather Service
http://www.crh.noaa.gov/ncrfc - North Central River Forecast Center - Chanhassen, National Weather Service

ACKNOWLEDGEMENTS

- none

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