Minnesota Drought Situation Report - July 10, 2007
| Drought Monitor - July 3, 2007 |
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Drought Status
The latest U. S. Drought Monitor places portions of north central, northeastern,
east central, and south central Minnesota in the Moderate Drought category. Much of
the remainder of the eastern three quarters of Minnesota is depicted as being Abnormally Dry. The U. S.
Drought Monitor index is a blend of science and subjectivity where intensity categories are based on several indicators.
Last week's weather:
Precipitation last week was generally light across most of western and northern Minnesota. However, many locations in east central Minnesota received between one and
two inches of rain for the week. This was welcome precipitation in one of Minnesota's driest areas. It was a warm week with temperatures
averaging three to five degrees above average. Many communities reported temperatures above 90 degrees at least once during the week.
Seasonal weather overview:
Dryness has been entrenched across much of the southern two thirds of Minnesota for much of May, June, and early July. The timing of the dry weather
has been unfortunate. The period from May through September is historically the wettest time of the year in Minnesota. Long-term average
rainfall rates during this time interval are around one inch per week. Very dry weather, occurring during a time of year when ample rain is typical, leads to the rapid
intensification of drought. The lack of precipitation, along with very high evaporation rates in June, has led to deteriorating crop conditions, low
stream flows and lake levels, and increased the danger of wildfire.
Seasonal precipitation totals, departure, and ranking:
Rainfall totals since April 1 have been less than eight inches across much of the southern one half of Minnesota. Growing season rainfall totals
have deviated negatively from historical averages by more than three inches across much of east central, central, southwestern, and south central
Minnesota. Seasonal rainfall deficits exceeding four inches are reported along a band extending from the metropolitan area through Mankato and
southwestward into Fairmont. Spotty four-inch deficits are also reported in central Minnesota, and in southwestern Minnesota. When compared with other
seasonal rainfall totals to date in the historical database, this year's rainfall totals for the period rank below the 20th percentile
(one year in five) in the driest areas.
Sector briefs:
- Agriculture - The Agricultural Statistics Service reports that as of July 6, topsoil moisture for 58% of Minnesota's landscape was "Short" or "Very Short". Corn and soybean conditions have declined in response to the diminishing soil moisture reserves.
- Stream flow - Stream discharge in roughly one third of Minnesota's rivers and streams is below the 25th percentile when compared with historical data for this time of year. Flow conditions in some northeastern and east central Minnesota watersheds are near the protected flow threshold (lowest 10th percentile), leading the Department of Natural Resources to carefully monitor surface water appropriations in these areas. Mississippi River flow conditions remain very low along all of the upper reaches of the river.
- Lake levels - Lake levels continue to drop throughout Minnesota, exposing shoreline, and in some cases, making water access difficult. Quantitative lake level data are difficult to obtain in real time. However, anecdotal reports indicate that many lakes, especially in east central Minnesota, are a foot or more average levels for the date. Lake Superior water levels are near all-time lows for the date and may fall below all-time seasonal lows by early autumn.
- Wildfire Danger - Wildfire danger is Moderate or High across most of Minnesota. The wildfire danger is rated as Low in southeastern counties.
- Public water supply - Many Minnesota communities have imposed watering restrictions due to increased lawn watering demands.
More drought information resources are found at http://climate.umn.edu/doc/journal/drought_information_resources.htm.
Return to Minnesota Climatology Working Group Main page
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URL: http://climate.umn.edu/doc/journal/drought_situation_report_2007_070710.htm
Last modified: July 10, 2007