|HydroClim Minnesota - July 2004
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
- rainfall totals across much of Minnesota fell short of historical averages in June 2004. Rainfall was generally one to three inches below normal in most communities. Rainfall totals for some locations in north central Minnesota were less than one inch, ranking June 2004 among the driest on record. However, not all locations in Minnesota reported precipitation deficits during June. Portions of south central and southeastern Minnesota were extraordinarily wet, especially during the first half of the month.
- although June was a relatively dry month statewide, a few significant precipitation events were reported in southern sections of the state. Very heavy rains fell upon areas of south central and southeastern Minnesota on June 8 and 9. A series of thunderstorm complexes dropped five or more inches of rain along a band that extended from just west of Mankato, to Rochester, and southeast to Preston. Mudslides, urban and rural flooding, and road closures were common in these areas. On June 15 and 16, intense thunderstorms swamped portions of Pipestone and Murray counties with more than four inches of rain in a short period of time.
- as was the case in May, June 2004 temperatures were quite cool. June monthly mean temperatures were generally three to five degrees below normal. In some northern Minnesota communities, the May plus June mean temperature was among the coldest on record. Daily low temperature records were set throughout the month in many locations. The temperature extremes for June ranged from 97 degrees at Redwood Falls and Lamberton (Redwood county) on the 7th, to 22 degrees at Cook (St. Louis county) on the 4th.
WHERE WE STAND NOW
- growing season precipitation totals to date (April 1 - early July) are highly variable across Minnesota. Seasonal precipitation totals are short of the historical average over large sections of north central and northeastern Minnesota. Many of these areas have received less than 70 percent of normal growing season rainfall thus far. When compared with other April through early July periods in the historical database, this season's rainfall ranks below the 15th percentile in these locations. Conversely, growing season rainfall totals in portions of northwestern, central, south central and southeastern counties, have been very high. Rainfall since April 1 has exceeded the historical average by nearly ten inches in some southeastern Minnesota communities. In northwestern Minnesota and much of the southern one half of the state, growing season rainfall totals rank above the 75th percentile when compared with past years. In far southeastern counties, the growing season rainfall-to-date ranks above the 98th percentile.
- as of July 6, the National Drought Mitigation Center (NDMC) - U. S. Drought Monitor indicated that much of the state of Minnesota is free of drought designations. However, an area of north central and northeastern Minnesota is judged to be in the "D0 - Abnormally Dry" category. The NDMC index is a blend of science and subjectivity where intensity categories are based on six key indicators and numerous supplementary indicators.
- the Minnesota Agricultural Statistics Service reports that as of July 2, the state's topsoil moisture was 4% very short, 15% short, 76% adequate, and 5% surplus.
- stream gauging by the U.S. Geological Survey and DNR Waters indicate that stream discharge values vary widely across Minnesota. Stream levels in portions of north central and northeastern Minnesota rank below the 25th percentile for the date. In contrast, many streams in northwestern Minnesota, as well as streams in the southern one third of Minnesota, are discharging volumes that rank above the 75th percentile for the date.
- the potential for wildfires is rated by DNR Forestry as "low" across all of Minnesota.
- the July precipitation outlook from the Climate Prediction Center shows no significant tendencies away from climatological probabilities. July precipitation normals range from just over three inches in far northwestern Minnesota, to over four inches in eastern sections of the state.
- the July temperature outlook from the Climate Prediction Center indicates a tilt towards below normal temperatures for all of Minnesota. Normal July high temperatures are in the low to mid 80's. Normal July lows are around 60 degrees.
- the 90-day precipitation outlook for July through September shows no significant tendencies away from climatological probabilities. The July through September temperature outlook indicates a tilt towards below normal conditions for a significant portion of southern and central Minnesota.
- the National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. A hydrologic model is initialized using current conditions of stream flow and soil moisture across a basin. The model is allowed to run into the future with multiple scenarios using multiple years of historical climatological data. The climatological data are weighted by 90-day climate outlooks for temperature and precipitation trends. Model output offers a complete range of probabilistic values of stream stage and discharge for numerous forecast points. The product provides 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 are produced near the middle of each month.
FROM THE AUTHOR
NOTES FROM AROUND THE STATE
UPCOMING DATES OF NOTE
- July 15, Climate Prediction Center releases 30/90 day temperature and precipitation outlooksWEB SITES FEATURED IN THIS EDITION
http://climate.umn.edu - Minnesota Climatology Working Group
http://www.drought.unl.edu/ - National Drought Mitigation Center
http://www.nass.usda.gov/mn/ - Minnesota Agricultural Statistics Service
http://swroc.coafes.umn.edu/ - University of Minnesota Southwest Research and Outreach Center, Lamberton
- U.S. Geological Survey, Minnesota
- Minnesota Department of Natural Resources - Division of Waters
- Minnesota Department of Natural Resources - Division of Forestry
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.crh.noaa.gov/ahps - National Weather Service, Central Region Headquarters
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