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
WHAT HAPPENED IN
- 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
- 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.
- 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.
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.
- 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
- 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.
- 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.
- 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
- 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.
- 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.
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.
- 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
- 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.
- 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).
NOTES FROM THE AUTHOR
NOTES FROM AROUND THE STATE
UPCOMING DATES OF NOTE
- December 20: National
Weather Service releases 30/90 day temperature and precipitation
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
- 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
Minnesota DNR Enforcement
Climate Prediction Center, National Weather Service
North Central River Forecast Center - Chanhassen, National Weather Service
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