|HydroClim Minnesota - December 2003
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
WHAT HAS HAPPENED
- November 2003 precipitation totals fell short of normal by one half inch to one inch in most Minnesota counties. This continued a pattern of dryness that began in mid-July 2003. WHERE WE STAND NOW
- the most significant precipitation event of the month was a winter storm that moved through Minnesota on November 22 and 23. With the exception of far northwestern and far southeastern Minnesota, four or more inches of snow fell across the state. Eight to twelve inches of snow was deposited along a 30 mile wide band from Yellow Medicine county in west central Minnesota to Lake county in northeastern Minnesota.
- November mean monthly temperatures across Minnesota were near to somewhat below normal. Record cold minimum temperature records were set in some areas on November 7, 8, and 9. Temperature extremes for the month ranged from -19 degrees F at Embarrass (St. Louis county) on November 8, to 65 degrees F at Mankato on November 11.
- as of December 3, a moderate snow cover blankets portions of north central and northeastern Minnesota. Most locations in these areas have at least four inches of snow on the ground. Snow depths exceeding six inches are reported in all or portions of Beltrami, Koochiching, Itasca, St. Louis, Lake and Cook counties. Snow depths are generally two inches or less in the Red River valley and the southern one half of Minnesota.
- as of November 26, the National Drought Mitigation Center - U. S. Drought Monitor indicated that most of Minnesota was judged to be in the "D1 - Moderate Drought" category. Southeastern and south central Minnesota counties were rated in the "D2 - Severe Drought" to "D3 - Extreme Drought" classification. The NDMC index is a blend of science and subjectivity where intensity categories are based on six key indicators and numerous supplementary indicators.
- the Minnesota Agricultural Statistics Service reported in late October that the state's topsoil moisture was 22% very short, 42% short, 34% adequate, and 2% surplus. November snows may have improved topsoil conditions somewhat, but the second and third foot of the soil profile remain extremely dry. Relatively little overwinter precipitation infiltrates into frozen soil. Therefore, early spring rains will be crucial in replenishing the soil moisture reservoir.
- the U.S. Geological Survey indicates that stream discharge values for roughly 20 percent of Minnesota's rivers rank below the 25th percentile for the date. The remainder of the state's rivers rank between the 25th and 75th percentile when compared with historical stream flow data for the date.
- as of early December, Minnesota soils were frozen to a depth of zero to two inches in the south, four to eight inches in the north. Soil frost typically reaches maximum depth in late February.
- nearly all of Minnesota's smaller and shallower lakes are ice covered. Most of Minnesota's larger lakes have at least some areas of ice cover. Ice thickness is highly variable and ice safety is marginal. Those venturing onto the state's water bodies should utilize caution and common sense.
- the December precipitation outlook from the Climate Prediction Center shows no significant tendencies away from climatological probabilities. 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 the southwest. The December temperature outlook also shows no significant tendencies away from climatological probabilities. 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.
- the 90-day precipitation outlook for December through February shows no significant tendencies away from climatological probabilities. The December though February temperature outlook indicates a tilt towards above normal conditions.
- the National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. A hydrologic model is initialized using the current conditions of stream flow and soil moisture across a basin. The model is allowed to run into the future with multiple scenarios using more than 30 years of historical climatological data. The climatological data are weighted by 90-day climate outlooks for temperature and precipitation trends. Model output offers a complete range of probabilistic values of stream stage and discharge for numerous forecast points. The product provides a risk assessment tool which can be used in long-range planning decisions involving flooding or low flow concerns. These products are part of the National Weather Service's Advanced Hydrologic Prediction Service (AHPS) and are produced near the middle of each month.
FROM THE AUTHOR
NOTES FROM AROUND THE STATE
UPCOMING DATES OF NOTE
- December 18, Climate Prediction Center releases 30/90 day temperature and precipitation outlooksWEB SITES FEATURED IN THIS EDITION
http://climate.umn.edu - Minnesota Climatology Working Group
http://www.drought.unl.edu/ - National Drought Mitigation Center
- Minnesota Agricultural Statistics Service
http://mrcc.sws.uiuc.edu/ - Midwestern Regional Climate Center
http://swroc.coafes.umn.edu/ - University of Minnesota Southwest Research and Outreach Center, Lamberton
- U.S. Geological Survey, Minnesota
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.crh.noaa.gov/ahps - National Weather Service, Central Region Headquarters
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