HydroClim Minnesota - March 2006

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 3/8/06


- precipitation totals for February 2006 were below average in most Minnesota locations. Precipitation generally fell short of average by one third to one half inch. However, along an 80 mile-wide swath centered on a line from Moorhead to Duluth, February precipitation totals reached or somewhat exceeded historical averages. 
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )
- one of the larger snow producers of February occurred on the 16th when a winter storm moving through the Midwest dropped nearly 10 inches of snow on far-southeastern Minnesota. Rochester reported a daily snowfall total of 6.6 inches, a record for the date. Another storm system dropped 6 to 12 inches of snow along a narrow corridor from Bemidji to Duluth on February 24. 
(see: http://climate.umn.edu/doc/journal/snow060216.htm )
- February 2006 monthly mean temperatures were near average in the southern one half of Minnesota. In the northern half of the state, February temperatures were two to five degrees cooler than average. A warm start to the month was counterbalanced by a mid-month cold snap. The arctic outbreak on February 17 and 18 led to dangerous windchill temperatures in many areas. The temperature extremes for February ranged from 53 degrees at Winona on the 2nd, to -36 degrees at Embarrass (St. Louis county) on the 18th.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/windchill060217.htm , http://climate.umn.edu/doc/journal/balmy0506.htm )


- the snow depth map prepared on March 2 shows that the southern one third of Minnesota has two or less inches of snow cover at this time. The central third of Minnesota reports two to eight inches of snow on the ground, and the northern one third of the state is blanketed by a substantial snow cover. Many northern Minnesota counties report 18 inches of snow or more on the ground. Areas along the Lake Superior highlands continue to be covered by over two feet of snow. The tremendous variation of snow cover across Minnesota is also displayed in the snow depth ranking map. When placed in historical context, snow depths are greater than the historical median in the Red River basin, and below the historical median in the southern one third of the state. 
(see: http://climate.umn.edu/doc/snowmap.htm )
- as of late February, the state's snow pack contains water equivalent values that range from near zero in the snow-sparse areas of southern Minnesota, to over five inches along the Lake Superior highlands. Of particular note are the three to five-inch snow water equivalent values found in the upper (southern) reaches of the Red River basin. Snow water equivalent values are above the historical median throughout the Red River basin.
(see: http://www.crh.noaa.gov/images/ncrfc/data/flood_outlooks/2006_outlook/swe_sim.jpg , http://www.crh.noaa.gov/images/ncrfc/data/flood_outlooks/2006_outlook/swe_ranking.jpg )
- as of February 28, the National Drought Mitigation Center (NDMC) - U. S. Drought Monitor indicated that all Minnesota counties are free of drought designations. 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 )
- in their final soil moisture status summary of 2005, the Minnesota Agricultural Statistics Service reported that the state's topsoil moisture was 0% very short, 5% short, 86% adequate, and 9% surplus. The late-autumn soil moisture condition is indicative of the conditions to be expected at the start of the 2006 growing season.
(see: http://www.nass.usda.gov/mn/cwmn.htm )
- in those areas of northeastern and north central Minnesota with adequate snow cover before the mid-February cold snap, soil frost depths under sod remain around 12 inches. Elsewhere around the state, soil frost under sod has penetrated 18 to 30 inches below the surface. This season's frost depths are 6 to 12 inches shallower than average for the date. The frost depths have reached their maximum extent for the season. On average, all layers of the soil profile will thaw by late March to early April in the south, early April to mid-April in the north.
(see: http://climate.umn.edu/doc/observatory.htm , http://www.mvp-wc.usace.army.mil/projects/reservoirs.shtml )
- the U.S. Geological Survey reports that stream discharge values, for locations where winter measurements are possible, are well above the median for the date in the Red River basin. Elsewhere, stream flows are at or slightly above historical medians for the date.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd )


- due to conditions mentioned above, there is a significant probability of moderate to major spring flooding along the upper (southern) reaches of the Red River. There is a considerable chance of moderate flooding the lower reaches of the Red River basin. Unless the weather changes dramatically, spring flooding should not be a major concern elsewhere in Minnesota.
(see: http://www.crh.noaa.gov/ncrfc/?n=ncrfc_spring_outlook )
- the March precipitation outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. Normal March precipitation ranges from near three quarters of an inch in northwestern Minnesota to nearly 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 normal precipitation is 50 percent higher than February normal precipitation, the greatest percentage increase between any two successive months.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/precip/precip_norm_03.htm )
- the March temperature outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. Normal March high temperatures climb from the upper 20's early in the month to the low to mid-40's 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 20's in the north, near 30 in the south. 
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/temp_norm_adj/temp_norm_adj_03.htm )
- the 90-day precipitation outlook for March through May indicates no significant tendencies away from climatological probabilities across Minnesota. The March through May temperature outlook depicts a tilt towards below normal temperatures in northwest Minnesota. Elsewhere in Minnesota, the 90-day temperature outlook indicates no significant tendencies away from climatological probabilities. 
(see: http://www.cpc.ncep.noaa.gov/products/predictions/90day/lead01/index.html )


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- March 10, most National Weather Service Forecast Offices issue Spring Flood Forecasts 
- March 16, Climate Prediction Center releases 30/90 day temperature and precipitation outlooks


http://climate.umn.edu - Minnesota Climatology Working Group
http://www.crh.noaa.gov/ncrfc/ - National Weather Service, North Central River Forecast Center
http://www.drought.unl.edu - National Drought Mitigation Center
http://www.nass.usda.gov/mn/ - Minnesota Agricultural Statistics Service
http://www.mvp-wc.usace.army.mil/ - U.S. Army Corps of Engineers, St. Paul District
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey
http://www.cpc.ncep.noaa.gov - Climate Prediction Center


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