|HydroClim Minnesota - June, 2000
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:
- precipitation shortfalls over the period October, 1999 through April,
2000 led to significant deficits in surface hydrology normally benefiting from autumn
recharge, spring snow melt runoff, and early spring rains. The situation was most acute in
southwestern Minnesota where the dry spell commenced in July, 1999. The extended dry spell
manifest itself in lower lake levels, dry wetland complexes, reduced stream flow, and dry
soils. For southern Minnesota counties, the dry spell abruptly ended in May. These areas
received abundant to excessive precipitation during the month, easing or eliminating the
concern for drought. However, the relief was not universally distributed. Precipitation
totals for portions of east central, northeastern, and northwestern Minnesota are below
normal for the growing season.
- precipitation totals for the month of May were generally near average in central and
northern Minnesota, and much above average across the southern third of Minnesota. In some
areas of southern Minnesota, May precipitation totals exceeded the average by three to
five inches. This large positive departure does not include totals from a major rainfall
event that ended on June 1. For some southeastern Minnesota communities, rainfall amounts
exceeded twelve inches from mid-May to early June. Two very notable precipitation events
drenched southern Minnesota in May. The first event occurred May 17-18. Precipitation
totals from this storm ranged from two to six inches across a multi-county area, with
values exceeding six inches in areas of Freeborn and Mower counties. In many counties, the
rain was welcome break in an extended dry spell. The second large southeastern Minnesota
rainfall event happened on May 31 and June 1. In this storm, precipitation totals ranged
from two to five inches across a multi-county area and the heavy rains hit in the same
locales that received two to six inches of rain on May 17-18. Significant urban and rural
flooding, and soil erosion were caused by this event.
- May temperatures were somewhat above historical averages throughout Minnesota. The month
began very warm, with some locations topping 90 degrees during the first week of the
month. The temperatures cooled significantly by mid-month and the month's end, but the
monthly average still finished above average.
WHERE WE STAND NOW:
- as of their May 30th release, the National Drought Mitigation Center
no longer classifies any Minnesota region in a drought category. Only four weeks ago,
southwestern Minnesota was experiencing "Severe Drought", and the remainder of
southern Minnesota was listed at the "First Stage Drought" level. Presently,
some areas of northwestern and west central Minnesota are currently in the "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
- the June 3rd Palmer Drought Index depicts all of Minnesota in the "Near
Normal" category with the exception of south central Minnesota, which is labeled as
experiencing an "Unusual Moist Spell". The Palmer Drought Index is used for
assessing long-term meteorological conditions.
- the Minnesota Agricultural Statistics Service reports that topsoil moisture conditions
across the state were rated 3% very short, 4% short, 74% adequate, and 19% surplus as of
Friday, June 2. They report that in the northern part of the Red River Valley, topsoil
moisture has become very short. Plant available soil moisture measured at the U. of M.
facility in Waseca (Waseca county) exceeds 14 inches in a five foot profile, well above
field capacity. Plant available moisture measured at Lamberton (Redwood county) has risen
to five and one half inches, a significant rise since May 1. Measurements at both
locations are taken at plots planted in corn, soybeans, or a corn/soybean rotation.
- current stream discharge values for most Minnesota streams rank between the 25th and
75th percentile for this time of year. According to U.S. Geological Survey reports, some
stream flows fall below the 25th percentile in east central, northeastern, and
northwestern Minnesota. Conversely, flows rank above the 90th percentile in most southern
Minnesota streams. DNR Waters reports that the heavy late May rains in southeastern
Minnesota caused what is initially being considered a 50-year flood event on the Root
River. The stream gauge on the Root River at Lanesboro was destroyed by the flooding.
- lake levels in southwestern Minnesota have risen somewhat since
early spring. Some Minnesota lakes with significant stream inflows have risen as well.
Generally across the state, lake levels are remaining steady.
- water levels in many wetland complexes remain low, and in some areas of east central
Minnesota the wetlands are completely dry.
- the May rains diminished the potential for wildfires in all but far northeastern
Minnesota. In northeastern Minnesota, the fire danger is categorized as moderate in most
areas, very high in the "blow down" zones.
- the 30-day outlook from the Climate Prediction Center calls for near
normal June precipitation across Minnesota. Normal June precipitation ranges from three
and one half inches in the northwest, to five inches in the southeast. The June
temperature outlook tilts towards above normal conditions statewide. Normal high
temperatures climb from near 70 in early June to near 80 by the end of the month. Normal
June lows are mainly in the 50's.
FROM THE AUTHOR:
- the 90-day outlook for June through August tilts towards below-normal precipitation
statewide. The June through August temperature outlook indicates above-normal conditions
- one short month ago, this newsletter stated that the "precipitation deficits
leave Minnesota's water resources very dependent on adequate spring and summer
rains". Demonstrating remarkable capacity for change, Minnesota weather patterns
changed abruptly and brought more than "adequate" rains to many critically dry
areas. The focus on dryness now shifts from southwestern Minnesota to some areas of east
central and northwestern Minnesota. Drought information resources can be found on the
State Climatology Office Web site at http://climate.umn.edu/doc/drought_2000.htm
NOTES FROM THE FIELD:
- east central Minnesota: "my personal rain gage for the
month of May, had 1.74" total, while here at the Cambridge office we measured
2.62". My observations from around the county are that it is still deficient. I know
my protected wetland is down more than 6" from the end of March until now. Lake
levels in Chisago County are quite low. Comfort Lake last week was at it's lowest recorded
level since 1988. I have numerous reports of dried wetlands. Some folks are reporting they
are not able to use their boat lifts."
UPCOMING DATES OF NOTE:
- with temperatures climbing and plants now actively growing, evapotranspiration is on the
increase. Rainfall rates during the summer are often matched or exceeded by
evapotranspiration rates and therefore much of the summer rainfall is "consumed"
by the evapotranspiration process. Unless rainfall significantly exceeds average, surface
and near-surface ground water levels will not rise, but rather they will likely drop.
- in southeastern Minnesota communities where the May rains were excessive, soils remain
saturated. The saturated soils, in tandem with the steep terrain of the area, makes these
areas particularly vulnerable to flooding in the near term.
- June 15, Climate Prediction Center releases 30/90 day outlooks
WEB SITES FEATURED IN THIS EDITION:
http://climate.umn.edu - Minnesota Climatology
http://enso.unl.edu - National Drought Mitigation Center
http://www.cpc.ncep.noaa.gov - Climate
http://www.dnr.state.mn.us/waters/ - DNR
- U.S. Geological Survey, Minnesota
http://www.nass.usda.gov/mn/ - Minnesota
Agricultural Statistics Service
DNR Wildfire Information Center
Mike Mueller, DNR Waters Hydrologist - Cambridge
Bob Potocnik, DNR Waters Surface Water Specialist - St. Paul
Dana Dostert, DNR Waters Hydrologist - St. Paul
Dave Ruschy, Department of Soil, Water and Climate - U. of. M
Mark Seeley, Agricultural Meteorologist - U. of M. Extension Service
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