|HydroClim Minnesota - November 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
- September precipitation
patterns were highly variable. September precipitation totals in
northwestern and west central Minnesota were somewhat above average.
Conversely, precipitation in northeastern and south central counties was
one to two inches below the norm. Elsewhere across the state, September
precipitation was close to the long-term mean. October precipitation was
also highly variable across the state. The northern one third of Minnesota
received somewhat above average precipitation, whereas precipitation
across the remainder of the state fell short of average by about one inch.
- the first blizzard conditions and heavy snow of the
season occurred on October 24 and 25. Record breaking October snowfall
fell in many northwestern Minnesota locations. Argyle (Marshall County)
received a whopping 14 inches of snow. Hallock in Kittson County received
10 inches of snowfall. Eight inch snowfall totals were reported Crookston,
Thief River Falls, and Roseau. Four inch totals were common across the
remainder of the northern one half of Minnesota. High winds accompanying
this powerful winter storm topped 40 miles per hour across most of the
state. Very warm temperatures in the last few days of October and the
first week of November has eliminated the snow cover.
- September average temperatures finished near historical
averages across Minnesota. Record warm temperatures early in the month
were offset by cool mid and late-September weather. October temperatures
also finished close to the historical mean. Like September, October
offered wide swings in temperature. Record or near-record temperatures
were reported early in the month, whereas very chilly weather prevailed in
the later half of October.
WHERE WE STAND NOW
- seasonal precipitation
maps from April 1 to November 5 reveal a highly variable pattern across
Minnesota. Precipitation totals in far north central and northeastern
Minnesota are very high for the period, ranking above the 95th percentile
when compared to historical data for these months. Conversely, dry weather
in central Minnesota has more than counterbalanced the impact of an
extremely wet spring. In many of these areas, aggregate precipitation
totals for April through October fall well below the historical median.
Mid and late-summer precipitation shortfalls, along with a dry autumn,
have led to an expanding area of moisture deficits in southwestern,
central, and east central Minnesota.
- as of November 1, the National Drought Mitigation Center
places a swath of counties through southwestern, central, and east central
Minnesota in their "DO" category ("Abnormally Dry").
The NDMC index is a blend of science and subjectivity where intensity
categories are based on six key indicators and numerous supplementary
- the November 3 Palmer Drought Severity Index (PDSI) from
the Climate Prediction Center depicts southwestern, central, and east
central Minnesota in the "moderate drought" category. The
remainder of Minnesota is classified as "Near Normal". The
Palmer Drought Severity Index is used for assessing long-term
- the Minnesota Agricultural Statistics Service reports
that topsoil moisture as of Sunday, November 4 was rated 12% surplus, 65%
adequate, 19% short, and 4% very short. They state that precipitation is
needed before the ground freezes in order to replenish subsoil moisture.
- lake levels have dropped
significantly in many areas from the record or near-record elevations
reported this past spring. Lake levels remain relatively high in west
central, northwestern, and far northern Minnesota. Lake levels are
somewhat below average in central Minnesota, including metro lakes. Water
levels in the Brainerd and Grand Rapids areas are near average for the
(lake level information for individual lakes can be found at:
- the U.S.
Geological Survey indicates that most stream flows in Minnesota fall in
the normal category for the date. However, some exceptions exist. Stream
flows on the Red River and its tributaries are relatively high, ranking
above the 75th percentile. In some of these locations the discharge
exceeds the 90th percentile. Stream flows in some east central Minnesota
counties are relatively low, ranking below the 25th percentile for this
time of year.
- the potential for wildfires is rated as "high"
in east central Minnesota. Much of southern and central Minnesota, and
some northern Minnesota counties are in the "moderate" potential
category. Elsewhere across Minnesota, fire danger is characterized as
"low" (see NOTES FROM AROUND THE STATE below)
- the November precipitation outlook from the
Climate Prediction Center tilts towards above normal values. November
precipitation normals range from just under one inch in western Minnesota
to around one and one half inches in eastern sections of the state. The
average date of the first one inch snow cover ranges from the first week
of November in northeastern Minnesota, to the final week of November in
south central counties. The November temperature outlook leans towards
colder than normal conditions. Normal November high temperatures are in
the mid to upper-40's to start the month, dropping to the upper-20's by
month's end. Normal lows are in the upper-20's early in the month, falling
into the low-teens by late November.
- the 90-day precipitation outlook for November through January shows no
significant tendencies away from climatological probabilities. The
November though January temperature outlook tilts towards below normal
conditions. An important factor determining winter weather in the Midwest
is the state of sea surface temperatures in the equatorial Pacific (El
Niņo and La Niņa). At this time, neither El Niņo nor La Niņa
conditions are prevalent. Climatologist sometimes jokingly refer to this
as a "La Nada" condition. During "La Nada", winter
weather in the Midwest can be quite variable, alternating between cold and
mild spells, with intermittent snowy and dry periods.
- the National Weather Service produces long-range probabilistic river
stage and discharge outlooks for the Red River and Minnesota 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
climatological data. The climatological data are weighted by the 90 day
outlooks for temperature and precipitation trends. The model output offers
a complete range of probabilistic values of stream stage and discharge for
numerous forecast points. The product offers 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 will be
produced near the middle of each month. The AHPS service will be available
for the Mississippi River Basin in the autumn of 2002.
FROM THE AUTHOR
- the growing season of 2001 was divided into two
very distinct precipitation regimes. The period from April 1 until the
third week of June was extraordinarily wet, ranking among the wettest
springs on record. During the third week of June, the jet stream abruptly
pushed north of the international border. The shift in the storm track has
prevailed to this date, causing many storm systems to miss the state or to
brush only the northern tier of counties. Surface hydrology in central
Minnesota, including soil profiles, were maintained this summer by
reserves built up during the wet early season. The bank account is running
short in these areas, and late autumn recharge would be a welcome addition
to surface water levels. Soil freeze-up is imminent. Therefore, early
spring recharge will be especially critical in replenishing soil moisture
NOTES FROM AROUND THE STATE
- from Jeff Edmonds, Fire Information Officer, DNR
Recent record-setting high temperatures and strong
winds are pushing wildfires in central Minnesota beyond what is normally
seen in November. Fires are behaving much as they do during the spring
fire season, burning rapidly in dry grasses and brush. Soils are so dry in
the central part of the state that peat fires are beginning to show up,
requiring several days of extensive mop-up.
UPCOMING DATES OF NOTE
- November 15, Climate Prediction Center releases 30/90 day temperature and
WEB SITES FEATURED IN THIS EDITION
http://climate.umn.edu - Minnesota Climatology Working Group
http://enso.unl.edu/ndmc/ - National Drought Mitigation Center
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.nass.usda.gov/mn/ - Minnesota Agricultural Statistics Service
- Minnesota Department of Natural Resources
- U.S. Geological Survey, Minnesota
http://www.dnr.state.mn.us/forestry/fire/ - Minnesota Department of Natural Resources - Division of
Forestry http:/www.crh.noaa.gov/ahps/index.html - National Weather Service - Central Region Headquarters
- Bob Potocnik, Surface Water Specialist, DNR Waters
- St. Paul
Dana Dostert, Hydrologist, DNR Waters - St. Paul
Mark Seeley, Professor, University of Minnesota - St. Paul
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