HydroClim Minnesota - July 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 7/3/2007 (released one day early because of holiday)

WHAT HAPPENED IN JUNE

- June 2007 precipitation totals were quite variable across Minnesota. Many west central, northwest, and northeastern Minnesota locations reported above-average precipitation for the month. In some communities in these areas, rainfall totals topped six inches for the month. Elsewhere in Minnesota, June rainfall totals were very light. Some central, east central, south central, and southwestern Minnesota communities reported monthly rainfall totals of less than two inches. This is two or more inches less than the historical average for the month. In many of these areas, the dry weather marked the second consecutive month of below-average rainfall. The dryness has raised concerns about deteriorating soil moisture supplies and lower than average surface water levels.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp)
- torrential rains in early June in west central and northwestern Minnesota, falling upon an already saturated landscape, led to rural flooding. Some roadways were inundated and crop replanting was necessary in some spots. The heavy rain also led to flooding along the Red River and some of its tributaries throughout the month of June.
- the heaviest rain event of the month occurred on June 13 and 14 in eastern Polk and northern Clearwater counties. A sequence of thunderstorms dropped a narrow band of over six inches of rain in a 36 hour period in this area.
- monthly mean temperatures for June 2007 were warm across Minnesota. Temperatures for the month were generally two to four degrees above the historical average. Extreme values for June ranged from 94 degrees at Moorhead on the 11th, to 30 degrees at Hibbing on the 6th and at Embarrass (St. Louis County) on the 29th.(see: http://climate.umn.edu/cawap/monsum/monsum.asp )

WHERE WE STAND NOW

- growing season precipitation totals to date (April 1 through early July) demonstrate the striking spatial variation that is often observed in a state of Minnesota's size and continental position  Portions of west central and northwestern Minnesota are near all-time record high precipitation values for the period. By contract, some sections of central, east central, and southwestern Minnesota have received less than 75% of their normal growing season rainfall. In these drier areas, precipitation has fallen short of historical averages by three or more inches since April 1. Growing season rainfall deficits in the metropolitan area have topped five inches.(see: http://climate.umn.edu/doc/weekmap.asp )
- the U. S. Drought Monitor released on June 28 indicates that portions of north central and northeastern Minnesota are in a "Moderate Drought". This categorization is the result of lingering moisture deficits established during the very dry 2006 growing season and a snow-sparse winter. Fortunately, conditions throughout northern Minnesota have improved greatly from the "Extreme Drought" situation that existed only a few months ago. Other areas of Minnesota are drifting in a different direction. Much of central and eastern Minnesota (including the metropolitan area) is placed in the "Moderate Drought" category. In these counties, below-average rainfall in May and June combined with warm June temperatures to create deficits in topsoil moisture and lower-than-average levels in surface water systems. Much of the remainder of the eastern two thirds of Minnesota is considered to be "Abnormally Dry". The NDMC 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://drought.unl.edu/dm/6_week.gif )
- the U.S. Geological Survey reports that stream discharge values in many north central, northeastern, central, east central, and south central Minnesota watersheds are below the 20th percentile for the date. Stream flow in some northeastern and east central Minnesota basins has dropped below the 10th percentile for the date. Conversely, many locations along the Red River report stream discharge values that exceed the 90th percentile for the date. 
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd , http://www.crh.noaa.gov/ahps2/index.php?wfo=fgf , http://climate.umn.edu/dow/weekly_stream_flow/stream_flow_weekly.asp )
- water levels on Lake Superior remain just above the all-time record minimum for the date. Water levels on many lakes in the metropolitan area and northward to the Duluth area are below historical averages. Water levels on lakes in northern Minnesota have rebounded from last year's precipitation deficits and are approaching average values.
(see: http://www.lre.usace.army.mil/_kd/Items/actions.cfm?action=Show&item_id=3886&destination=ShowItem , http://www.lwcb.ca/waterflowdata.html )
- the Minnesota Agricultural Statistics Service reports that as of July 1, the state's topsoil moisture was 10% very short, 34% short, 51% adequate, and 5% surplus. A decline in crop conditions from the previous week was noted.
(see: http://www.nass.usda.gov/Statistics_by_State/Minnesota/Publications/Crop_Progress_&_Condition/index.asp )
- the potential for wildfires is rated by DNR Forestry as "moderate" in most Minnesota counties. Wildfire potential is depicted as "low" in southeastern Minnesota and some far northwestern and north central counties.
(see: http://www.dnr.state.mn.us/forestry/fire/ )

FUTURE PROSPECTS

- the July precipitation outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. July precipitation normals range from just over three inches in far northwestern Minnesota to over four inches in eastern sections of the state.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/precip/precip_norm_06.htm )
- the July temperature outlook indicates no significant tendencies away from climatological probabilities across Minnesota. Normal July high temperatures are in the low to mid 80's. Normal July lows are around 60 degrees. July is the warmest month of the year in Minnesota.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/temp_norm_adj/temp_norm_adj_06.htm )
- the 90-day precipitation outlook for July through September indicates no significant tendencies away from climatological probabilities across Minnesota. The July through September temperature projection tilts towards above-normal conditions across the northern one half of Minnesota, with no significant tendencies away from climatological probabilities in southern Minnesota.
(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/ )

NOTES FROM THE AUTHOR

- none

NOTES FROM AROUND THE STATE

- none

UPCOMING DATES OF NOTE

- July 19: 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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