HydroClim Minnesota - August 2007

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 8/8/2007

WHAT HAPPENED IN JULY

- July 2007 rainfall totals were well below historical averages in most Minnesota communities. Many locations reported less than two inches of rain for the month. Most locations in west central, central, and southwestern Minnesota received less than one inch of rain in July. Hutchinson reported their 2nd driest July in history with 0.50 inch of rainfall for the month. A 0.30 inch July rainfall total in Pipestone was also the second driest on record. The monthly rainfall total for Redwood Falls was 0.16 inch, the driest July in their historical record.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/warm0707.htm , http://climate.umn.edu/weathertalk/070803.txt , http://www.crh.noaa.gov/crnews/display_story.php?wfo=fsd&storyid=9444&source=0 , http://web.stcloudstate.edu/raweisman/monthlysummaries/jul2007.html )
- rainfall for the eight-week period from June 5 through July 30 totaled less than three inches over much of the southern two thirds of Minnesota. In most of these areas, rainfall totals for the period were four or more inches short of the historical average. When compared with historical rainfall totals for the same eight-week time frame, 2007 values ranked at or below the 5th percentile for many central and southern Minnesota counties. In a few areas, the June 5 - July 30 rainfall totals were near all-time record low values.
(see: http://climate.umn.edu/doc/journal/drought_situation_report_2007_070807.htm#mid_summer )
- monthly mean temperatures for July 2007 were near, to somewhat above, historical averages across Minnesota. A spell of seasonally cool weather during the middle of the month was counterbalanced by a warm finish to the month. Extreme values for July ranged from a high of 101 degrees at Browns Valley (Traverse County) and Canby (Yellow Medicine County) on the 7th, to a low of 32 degrees at Embarrass (St. Louis County) on July 13.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )


WHERE WE STAND NOW

- growing season rainfall totals (April 1 to present) are less than nine inches across much of central Minnesota. Seasonal rainfall totals have deviated negatively from historical averages by more than four inches across many central, east central, southwestern, and south central Minnesota counties. This is roughly the equivalent of missing all of June's rainfall. Seasonal rainfall deficits exceeding six inches are reported in a band that extends from Litchfield in central Minnesota eastward into portions of the Twin Cities metropolitan area. Six-inch shortfalls are also in place in some south central Minnesota counties. When compared with other seasonal rainfall totals-to-date in the historical database, this year's rainfall for the season ranks just above the 10th percentile (one year in ten occurrence) in many Minnesota counties.
(see: http://climate.umn.edu/doc/journal/drought_situation_report_2007_070807.htm#growing_season , http://climate.umn.edu/doc/weekmap.asp )
- the U. S. Drought Monitor released on July 31 places portions of northeastern Minnesota, and most of the southern one half of Minnesota, in the Severe Drought category. With the exception of northwestern counties, the remainder of Minnesota is classified as experiencing a Moderate Drought or depicted as being Abnormally Dry. The drought situation in the northern one third of Minnesota is the result of the lingering impacts of a very dry 2006, a snow-sparse 2006-2007 winter, and dry 2007 mid-summer weather. The drought situation in the southern two thirds of Minnesota is due to an extremely dry 2007 growing season. The U. S. Drought Monitor index is a blend of science and subjectivity where intensity categories are based on several indicators.
(see: http://www.drought.unl.edu/dm/monitor.html , http://climate.umn.edu/img/journal/drought_2007/dm_animation_070731.gif )
- the U.S. Geological Survey reports that stream discharge values in roughly 45% of Minnesota's rivers and streams are below the 25th percentile when compared with historical data for this time of year. Flow conditions in many northeastern, central, and east central Minnesota watersheds fall below the 10th percentile for the date, leading the Department of Natural Resources to suspend surface water appropriation permits in some areas. Mississippi River flow conditions remain very low along the upper reaches of the river. Mississippi River discharge near Anoka is at roughly the same flow rate as it was during the heart of some of Minnesota's more famous droughts (1976, 1988, 2006).
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd , http://climate.umn.edu/dow/weekly_stream_flow/stream_flow_weekly.asp , http://climate.umn.edu/img/journal/drought_2007/mississippi_discharge_070806.pdf )
- lake levels continue to drop throughout Minnesota, exposing shoreline, and in some cases, making water access difficult. Anecdotal reports indicate that many lakes, especially in central and east central Minnesota, are a foot or more below average levels for the date. The Lake Superior water level is near an all-time low for the date and could fall below the all-time seasonal low by early autumn.
(see: http://www.lre.usace.army.mil/_kd/Items/actions.cfm?action=Show&item_id=3886&destination=ShowItem , http://www.dnr.state.mn.us/lakefind/ )
- the Minnesota Agricultural Statistics Service reports that as of August 3, topsoil moisture across nearly 85% of Minnesota's landscape was "Short" or "Very Short". Corn and soybean conditions in many areas continue to decline in response to the diminishing soil moisture reserves. Only 25% of Minnesota's corn acreage is considered to be in "Good" or "Excellent" condition. A federal agricultural disaster has been declared for 24 Minnesota counties suffering from drought. Farmers and ranchers in an additional 32 adjacent counties will also be eligible for drought recovery assistance.
(see: http://www.nass.usda.gov/Statistics_by_State/Minnesota/Publications/Crop_Progress_&_Condition/index.asp , http://www.governor.state.mn.us/mediacenter/pressreleases/PROD008255.html )
- the DNR Division of Forestry classifies current wildfire danger as "High" or "Very High" across much of central, east central, and northeastern Minnesota. Most of the remainder of the state is depicted in the "Moderate" danger category.
(see: http://www.dnr.state.mn.us/forestry/fire/ )


FUTURE PROSPECTS

- the August precipitation outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. August precipitation normals range from under three inches in northwestern and west central Minnesota to over four and one half inches in southeastern counties.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/precip/precip_norm_08.htm )
- the August temperature outlook indicates no significant tendencies away from climatological probabilities across Minnesota. Normal August high temperatures are around 80 degrees to start the month, dropping to the mid-70's by month's end. Normal lows are around 60 degrees early in the month, falling to the mid-50's by late August.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/temp_norm_adj/temp_norm_adj_08.htm )
- the 90-day precipitation outlook for August through October indicates no significant tendencies away from climatological probabilities across Minnesota. The August through October temperature projection tilts towards above-normal conditions across northeastern Minnesota, with no significant tendencies away from climatological probabilities elsewhere.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/90day/lead01/index.html )
- the National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. These products are part of the National Weather Service's Advanced Hydrologic Prediction Service (AHPS).
(see: http://www.crh.noaa.gov/ncrfc/ )
- until drought conditions improve in the Upper Mississippi River basin, the National Weather Service will routinely produce low flow projections for the Mississippi River near Anoka.
(see: http://www.crh.noaa.gov/crnews/display_story.php?wfo=ncrfc&storyid=9487&source=0 )


NOTES FROM THE AUTHOR

- none

NOTES FROM AROUND THE STATE

- none

UPCOMING DATES OF NOTE

- August 16: National Weather Service releases 30/90 day temperature and precipitation outlooks

WEB SITES FEATURED IN THIS EDITION

http://climate.umn.edu - Minnesota Climatology Working Group, Minnesota DNR Waters and University of Minnesota Department of Soil, Water, and Climate
http://www.drought.unl.edu - National Drought Mitigation Center
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey
http://www.dnr.state.mn.us/waters - Minnesota DNR Waters
http://www.lre.usace.army.mil - Detroit District, US Army Corps of Engineers
http://www.nass.usda.gov - USDA, National Agricultural Statistics Service
http://www.dnr.state.mn.us/forestry - Minnesota DNR Forestry
http://www.cpc.ncep.noaa.gov - Climate Prediction Center, National Weather Service
http://www.crh.noaa.gov/ncrfc - North Central River Forecast Center - Chanhassen, National Weather Service

ACKNOWLEDGEMENTS

- none

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