|HydroClim Minnesota - December 2001
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 precipitation was
well above average in southwestern, south central, west central, and
central Minnesota. Precipitation totals in these areas were one and one
half to three and one half inches above normal. Elsewhere, precipitation
was near normal in northwestern and southeastern Minnesota, and somewhat
above normal in north central, northeastern, and east central Minnesota.
Precipitation was scarce during the first three weeks of November, then
two large-scale events dropped significant amounts of precipitation on
much of the state in the last eight days of the month. A slow moving storm
system moved through the Midwest on the 23rd and 24th, drawing warm, moist
air into Minnesota. The storm dropped one to three inches of rain over a
broad area of Minnesota. Yet another major storm moved through the region
only two days later on the 26th and 27th of the month. This storm left a
blanket of wet, heavy snow across many Minnesota counties. Snowfall totals
topped 24 inches in Kandiyohi county, and exceeded 12 inches in many
southwestern and central Minnesota communities. Heavy winds associated
with this major winter storm created Lake Superior waves that pounded
Duluth's lakefront and led to some damage.
- the heavy late November rainfall and snowfall
brought relief to areas affected by precipitation deficits established
during the later part of the 2001 growing season. Growing season
precipitation totals in southwestern, central, east central Minnesota
counties were significantly below normal, and the lack of soil moisture
reserves available for the 2002 growing season was a concern. However,
because the considerable November precipitation fell before soil
freeze-up, the soil moisture profile has been amply recharged. While the
soil laid first claim to the November precipitation, water levels in
surface hydrology systems such as lakes, rivers, and wetlands are rising
in response to the rain and snow melt.
- as of November 27, the National Drought Mitigation Center shows Minnesota to be free of any 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://enso.unl.edu/monitor/monitor.html )
- the December 1 Palmer Drought Severity Index (PDSI) from the Climate Prediction Center depicts all Minnesota counties in the "near normal" category. 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 )
- in their final report of the season, the Minnesota Agricultural Statistics Service reported that topsoil moisture as of November 9 was rated 6% surplus, 56% adequate, 32% short, and 6% very short. This survey was conducted before the heavy rains and snow of late November. Anecdotal reports indicate that late-November precipitation was very efficient in replenishing the still unfrozen soil moisture profile.
(see: http://www.nass.usda.gov/mn/cwmn.htm )
- the U.S. Geological Survey indicates that 95 percent of Minnesota's streams are in the normal or above normal categories for the date. 25 percent of Minnesota's stream gauging stations report stream discharge above the 90th percentile for this time of year. The highest stream flows (relative to historical data) are found in the Red River basin, scattered areas of northern Minnesota, and southeastern Minnesota.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd )
- most soil temperatures in Minnesota continue to remain above freezing. The extraordinarily warm temperatures of November and the insulating effect of the late November snow have combined to delay soil freeze up. Similarly, the formation of lake ice has been delayed or slowed by this combination of factors. While some smaller and shallower lakes are thinly covered with ice, many larger Minnesota lakes remain ice-free.
(see: http://climate.umn.edu/cawap/soilpan/011202.txt , http://climate.umn.edu/doc/observatory.htm )
- 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 just over one inch 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 to upper-20's to start the month, dropping to the near 20 by
month's end. Normal lows are around 10 degrees early in the month, falling
to near zero by late December.
FROM THE AUTHOR
UPCOMING DATES OF NOTE
- December 13, Climate Prediction Center releases 30/90 day temperature and
WEB SITES FEATURED IN THIS EDITION
http://climate.umn.edu - Minnesota Climatology Working Group
- Amy Loiselle, DNR Waters Hydrologist - Eveleth
Contributions of information and suggestions are welcome!