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 1/8/03

WHAT HAS HAPPENED

- as was the case in November, December precipitation was quite light across nearly all of Minnesota. December precipitation totals ranged from 0.04 inch at Pipestone to 0.92 inches at Warroad. Precipitation totals for the month fell short of historical averages by approximately one half inch in all but northwestern Minnesota where December precipitation was near normal. In many communities, November plus December 2002 precipitation totals were among the driest on record. The only significant precipitation event of the month was a December 18 ice storm that created travel problems in central, north central and northeastern Minnesota. 
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )
- December mean temperatures were well above historical averages across all of Minnesota. December temperatures generally ranged from six to ten degrees above normal. Record high temperatures in the mid-40's were reported across northern Minnesota on December 10, 11, and 13.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )


WHERE WE STAND NOW

- as of January 8, very few areas in Minnesota are snow covered. A handful of communities in far northern counties report snow depths greater than 4 inches. Elsewhere, snow cover is less than 2 inches or completely absent. Across nearly all of Minnesota, early January snow depths fall below the 5th percentile when compared with historical snow cover for the date. In some locations, snow depths are at all-time lows for the date.
(see: http://climate.umn.edu/doc/snowmap.htm )
- as of January 7, the National Drought Mitigation Center - U. S. Drought Monitor indicates that the northern one third of Minnesota falls within the "D0 - Abnormally Dry" category. Far northeastern Minnesota is judged to be in the "D1 - Drought Moderate" category. All other Minnesota counties are free of drought designation. The NDMC index is a blend of science and subjectivity where intensity categories are based on six key indicators and numerous supplementary indicators.
(see: http://www.drought.unl.edu/dm/monitor.html )
- the January 4 Palmer Drought Severity Index map from the Climate Prediction Center places much of Minnesota in the "Near Normal" category. Only central Minnesota ("Very Moist Spell"), and east central Minnesota ("Unusual Moist Spell"), fall outside of the "Normal" designation. Recent dry weather has moved index values lower across all of Minnesota. The Palmer Drought Severity Index is used for assessing long-term meteorological conditions.
(see: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif )
- a year-end report from the Minnesota Extension Service indicates that stored soil moisture in the five foot profile is somewhat similar to last year in central counties, while the northwestern counties and some of the southern counties show greater moisture storage than this time last year. Soil surface layers are dry in response to the late autumn and early winter precipitation deficits. Soil moisture values in the mid and lower layers are ample.
(see: http://www.plpa.agri.umn.edu/extension/news%20releases/MNCN104.htm )
- the U.S. Geological Survey indicates that stream discharge values for approximately one half of Minnesota rivers (where winter reporting is possible) are in the normal category for the date. Another one third of Minnesota's streams rank above the 75th percentile for the date. Discharge values for northeast Minnesota streams are low, ranking below the 25th percentile for the date.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd )
- in spite of recent warm temperatures, frost depths across Minnesota are holding steady around 8 to 12 inches deep. Historically, frost steadily progresses deeper into the soil throughout the winter. Soil frost typically reaches maximum depth in late February. Without a snow cover, future intrusions of arctic air will cause frost to penetrate rapidly into the soil.
(see: http://climate.umn.edu/doc/observatory.htm , http://www.mvp-wc.usace.army.mil/projects/reservoirs.shtml ) 
- nearly all of Minnesota's lakes and ponds are ice covered. Ice thickness is highly variable and ice safety remains marginal in places. Some Minnesota rivers are free of ice.
(see: http://www.dnr.state.mn.us/enforcement/co_report/index.html )


FUTURE PROSPECTS

- the January precipitation outlook from the Climate Prediction Center shows no significant tendencies away from climatological probabilities. January precipitation normals range from one half inch in western Minnesota to near one inch in eastern sections of the state. The median snow cover at the end of January ranges from near 5 inches in the southwest Minnesota, to over 15 inches on the ground in northeastern Minnesota (greater than 24 inches in the Lake Superior highlands). The January temperature outlook indicates a strong bias towards above normal conditions. 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: http://www.cpc.ncep.noaa.gov/products/predictions/30day )
- the 90-day precipitation outlook for January through March shows no significant tendencies away from climatological probabilities for the northeastern four-fifths of Minnesota. The 90-day precipitation outlook for far southwestern counties tilts towards above normal conditions. The January though March temperature outlook indicates a strong bias towards above normal conditions.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/90day/lead01/index.html )
- the National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and upper 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. 
(see: http://www.crh.noaa.gov/ahps/index.html )


FROM THE AUTHOR

- none


NOTES FROM AROUND THE STATE

- none


UPCOMING DATES OF NOTE

- January 16, Climate Prediction Center releases 30/90 day temperature and precipitation outlooks 
- January 30, Interagency Flood Planning Coordination Meeting, Corps of Engineers - St. Paul


WEB SITES FEATURED IN THIS EDITION

http://climate.umn.edu - Minnesota Climatology Working Group
http://www.drought.unl.edu/ - National Drought Mitigation Center
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.plpa.agri.umn.edu/extension/ - University of Minnesota Plant Pathology Extension
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey, Minnesota
http://www.dnr.state.mn.us/enforcement - Minnesota DNR Enforcement
http://www.crh.noaa.gov/ahps/index.html - National Weather Service - Central Region Headquarters


ACKNOWLEDGEMENTS

Contributions of information and suggestions are welcome!