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

compiled 7/5/00


 - 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 dry spell.
(see: http://climate.umn.edu/doc/weekmap.asp)

- 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.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/flash_floods/ff000601.htm , http://climate.umn.edu/doc/journal/flash_floods/ff000620.htm)

- 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.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/whatsnew.htm)


- 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%.
(see: http://climate.umn.edu/doc/weekmap.asp)

- 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 supplementary indicators.
(see: http://enso.unl.edu/monitor/monitor.html)

- 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.
(see: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif)

- 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.
(see: http://www.nass.usda.gov/mn/cwmn.htm , http://climate.umn.edu/img/soil_moisture/wassm12.gif ,

- 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.
(see: http://water.usgs.gov/cgi-bin/daily_flow?mn , http://www.dnr.state.mn.us/waters/programs/surwat_section/stream_hydro/productsf.html)

- 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.
(see: http://www.ra.dnr.state.mn.us/fire/)


- 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.
(see: http://www.cpc.ncep.noaa.gov)

- 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.
(see: http://www.cpc.ncep.noaa.gov)


- 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 Working Group
http://enso.unl.edu - National Drought Mitigation Center
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.nass.usda.gov/mn/ - Minnesota Agricultural Statistics Service
http://swroc.coafes.umn.edu - University of Minnesota Southwest Research and Outreach Center
http://water.usgs.gov/cgi-bin/daily_flow?mn - U.S. Geological Survey, Minnesota
http://www.dnr.state.mn.us/waters/ - DNR Waters
http://www.ra.dnr.state.mn.us/fire/ - DNR Wildfire Information Center


Mark Seeley, Agricultural Meteorologist - U. of M. Extension Service
Dana Dostert, DNR Waters Hydrologist - St. Paul
Dave Ruschy, Department of Soil, Water and Climate - U. of M.
Gyles Randall, Soil Scientist - Southern Research and Outreach Center - U. of M. Waseca

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