|HydroClim Minnesota - July, 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:
- across Minnesota, the threat of drought has subsided. In many areas, June
brought a continuation of the wet weather that commenced in May. The two month wet spell
elevated surface hydrology systems lowered by autumn, winter and early spring
precipitation shortfalls. In some counties May/June precipitation was excessive, leading
to inundated fields, soil erosion, and urban flooding. Rainfall totals in portions of
southeastern, south central, and northwestern Minnesota are above historical averages by
more than ten inches for the growing season. While most of the state received abundant to
excessive early summer precipitation, growing season rainfall totals for some sections of
central and east central Minnesota are below normal. Scattered across Minnesota, surface
hydrology systems remain at lower than average levels, still recovering from the long-term
- precipitation totals for the month of June varied widely across Minnesota. Portions of southeastern, south central, and northwestern Minnesota reported record or near-record high rainfall amounts for the month. June records were set in Rochester (12.52 inches), Preston (11.86 inches), and Fargo/Moorhead (11.72 inches). These values are seven to nine inches above historical averages for those locations. By contrast, June precipitation totals were one to two inches below normal in some west central and central Minnesota counties.
- two notably heavy precipitation events occurred during the month of June in
Minnesota. The first event took place on May 31 and June 1 in southeastern Minnesota,
dropping heavy rains from Waseca to Houston counties. In this storm, precipitation totals
ranged from two to five inches across a multi-county area and the heavy rains fell on 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. The second major rain event of
the month soaked portions of Clay, Norman, Mahnomen, and Becker counties on June 19 and
20. Torrential rains exceeding six inches caused extensive urban flooding in the
Moorhead/Fargo area, led to significant stream flooding on tributaries of the Red River,
and submerged large tracts of agricultural land.
- June temperatures were generally below historical averages across Minnesota. This was
the first time since October, 1999 that monthly temperatures finished colder than normal.
Record cold temperatures were set on the morning of June 5, with many northern and eastern
Minnesota communities dropping below freezing. A brief heat wave followed only three days
later, bringing 100 degree temperatures to western and central Minnesota.
- precipitation totals for the growing season (April 1 to present) are 25% or more
above historical averages for much of the southern one third of Minnesota and for portions
of northwestern Minnesota. For some communities, growing season precipitation totals to
date are near or above all-time record high values. A portion of east central and central
Minnesota reports growing season rainfall values that are short of normal by 25%.
- as of their June 27 release, the National Drought Mitigation Center does not classify
any Minnesota region in a drought category. Eight weeks ago, southwestern Minnesota was
experiencing "Severe Drought", and the remainder of southern Minnesota was
listed at the "First Stage Drought" level. The NDMC index is a blend of science
and subjectivity where intensity categories are based on six key indicators and numerous
- the July 1 Palmer Drought Index depicts all of Minnesota in the "Near
Normal" category with the exception of south central and southeastern Minnesota.
Those regions are categorized 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 1% very short, 7% short, 72% adequate, and 20%
surplus as of Friday, June 30. They report that in Norman county, a large number of
agricultural acres have been lost to flooding. For portions of central Minnesota, subsoil
moisture remains short and timely rains will be essential. Plant available soil moisture
measured at the U. of M. facility in Waseca (Waseca county) is near field capacity. Plant
available moisture measured at Lamberton (Redwood county) in early July are not yet
available, but soil moisture has rebounded nicely from the significant deficits reported
early in the growing season. Measurements at both locations are taken at plots planted in
corn, soybeans, or a corn/soybean rotation.
- current 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 Minnesota. Conversely, flows rank
above the 75th percentile in many southeastern and northwestern streams. Some streams in
northwestern Minnesota are above the 90th percentile, still showing the affects of the
June 19-20 downpours.
- May and June rains diminished the potential for wildfires in all but far northeastern
Minnesota. In far northeastern Minnesota (including the "blow down" zones), the
fire danger is categorized as moderate.
- the 30-day outlook from the Climate Prediction Center calls for below normal July
precipitation across the southern one quarter of Minnesota, near normal elsewhere. Normal
July precipitation ranges from near three inches in the northwest, to just over four
inches in the southeast. The June temperature outlook is for near normal conditions
statewide. Normal July high temperatures are in the low to mid 80's (except near Lake
Superior) and normal July lows are in the upper 50's to low 60's.
- the 90-day outlook for July through September tilts towards below-normal
precipitation in the southern half of Minnesota, near normal elsewhere. The July through
September temperature outlook leans towards above normal conditions in the southern one
third of the state, near normal elsewhere.
- just two short months 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 during the month of June changed from precipitation deficits to
difficulties brought on by excessive precipitation.
- (from Dr. Gyles Randall - Soil Scientist, University of Minnesota Southern Research
and Outreach Center - Waseca) "... the negative consequences of the extremely heavy
rains the last six weeks are easily seen while traveling through south-central and
southeastern Minnesota. In the short-term, yields and profitability will be reduced in
many fields because of drowned out areas, soggy field conditions, and erosion. However, in
almost 30 years of conducting soils research in this area, never have I seen soil erosion
this severe and this extensive. Current cropping systems really need to be reexamined as
to their ability to sustain long-term productivity. Some of the most productive soils in
the world are located in this area, yet future productivity of these soils is seriously
being jeopardized. Boulders in the subsoil are being exposed where corn was planted only
two months ago. Disks are being used to fill in the gullies so that combines can go
through them this fall. Practices that should be considered to combat soil erosion in the
most susceptible areas of the landscape include establishing CRP areas, much wider grassed
waterways, buffer strips, and implementing very reduced tillage systems. These practices
can make a difference that will minimize degradation of our valuable soil resources and
protect them for future generations."
- July 13, Climate Prediction Center releases 30/90 day outlooks
http://climate.umn.edu - Minnesota Climatology
Mark Seeley, Agricultural Meteorologist - U. of M. Extension Service
Contributions of information and suggestions are welcome!