HydroClim Minnesota - May 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 5/2/07 (distributed one week early)

WHAT HAS HAPPENED

- April 2007 precipitation totals were above average across most of northern and central Minnesota. It was the third consecutive month of above average precipitation in many areas. Monthly precipitation was below average in south central and southeastern Minnesota. Monthly precipitation totals ranged from one to four inches statewide. West central Minnesota received the greatest amount of precipitation, with many locations reporting over four inches of liquid (melted snow plus rainfall). This is double the historical average.
(see: http://climate.umn.edu/doc/weekmap/weekmap_April_2007.htm)
- among the more notable weather events of April 2007 was an early spring snowstorm that dropped six or more inches of snow across central and northeastern Minnesota on April 2 and 3. Brainerd reported 11 inches of snow and Duluth set a local record (12.1 inches) for the greatest single-day snowfall total during the month of April. Another event on April 10 and 11 dropped three or more inches upon most of the southern one half of Minnesota. Fairmont reported a record 8.0 inches.
- monthly mean temperatures for April 2007 were near average across much of Minnesota. However, temperatures were two to four degrees below the historical average in west central Minnesota. Across the state, very cold temperatures in early April were offset by warmer than average temperatures during the later half of the month. It was the coldest start to an April in over 30 years. In many locations, daytime highs struggled to top the freezing mark during the first eleven days of the month. Extreme values for April ranged from 90 degrees at Worthington (Nobles County) on the 29th, to minus 8 degrees at Embarrass (St. Louis County) on the 9th.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://www.crh.noaa.gov/crnews/display_story.php?wfo=mpx&storyid=7196&source=0 )

WHERE WE STAND NOW

- the National Drought Mitigation Center (NDMC) - U. S. Drought Monitor released on April 26 indicates that portions of north central and northeastern Minnesota remain in a serious drought situation. Many other northern Minnesota counties are depicted in the "Moderate Drought" or "Abnormally Dry" categories. Because of significant precipitation over the last six weeks, the geographic extent of the drought-stricken areas has diminished somewhat. 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 Minnesota Agricultural Statistics Service reports that as of April 27, the state's topsoil moisture was 1% very short, 7% short, 79% adequate, and 13% surplus. In their previous week's release, the agency reported that subsoil moisture was "short" across much of north central and northeastern Minnesota.
(see: http://www.nass.usda.gov/Statistics_by_State/Minnesota/Publications/Crop_Progress_&_Condition/index.asp )
- the U.S. Geological Survey reports that stream discharge values are near historical medians across much of Minnesota. Stream flow in north central and northeastern Minnesota watersheds remains very low. Stream discharge in the upper reaches of the Red River and Minnesota River basins is high.
(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 )
- water levels on Lake Superior, as well as on many unregulated north central and northeastern Minnesota lakes, remain quite low. 
(see: http://www.lre.usace.army.mil/_kd/Items/actions.cfm?action=Show&item_id=3886&destination=ShowItem , http://www.lwcb.ca/waterflowdata.html )
- nearly all of Minnesota's lakes are now free of ice. As of Monday, large Canadian-border lakes such as Lake of the Woods, Rainy Lake, and Saganaga remained partially ice covered. Due to a warm late March, lakes in the southern one half of Minnesota lost their ice five to ten days earlier than average. An early-April cold snap put an abrupt end to the ice-melting process in those lakes that had not lost their ice. Some smaller lakes even experienced a brief re-freeze. Near to above-normal temperatures during the final weeks of April caused ice-out on northern Minnesota lakes to be near historical averages.
(see: http://climate.umn.edu/doc/ice_out/ice_out_status_07.htm , http://www.dnr.state.mn.us/ice_out/ )
- the potential for wildfires is rated by DNR Forestry as "high" today across much of Minnesota. There was intense fire activity in several areas this past weekend. Several thousand acres were burned. Seasonal temperatures, gusty winds, and dry weather this week dictate that a full complement of personnel, smoke chasers, and equipment is in place in most areas. Historically, 80 percent of all wildfires in Minnesota occur during April and May.
(see: http://www.dnr.state.mn.us/forestry/fire/ )

FUTURE PROSPECTS

- the May precipitation outlook from the Climate Prediction Center leans towards above-normal conditions throughout Minnesota. May precipitation normals range from just over two inches in northwestern Minnesota to just less than four inches in southeastern counties. The historical probability of measurable precipitation for any given day in May ranges from 25 percent in the northwest to near 40 percent in the southeast.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/precip/precip_norm_05.htm )
- the May temperature outlook offers a tilt towards above-normal conditions in eastern Minnesota. Elsewhere in Minnesota, the 30-day outlook indicates no significant tendencies away from climatological probabilities. Normal May high temperatures are in the low to mid-60's early in the month, rising to the low to mid-70's at month's end. Normal May low temperatures are in the mid-30's to near 40 to start the month and climb to the mid-40's to low 50's as the month ends.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/temp_norm_adj/temp_norm_adj_05.htm )
- the 90-day precipitation outlook for May through July indicates no significant tendencies away from climatological probabilities across Minnesota. The May through July temperature outlook indicates a tilt towards below-normal conditions in northwestern Minnesota. Elsewhere in Minnesota, the 90-day temperature outlook demonstrates no tendencies away from climatological probabilities.
(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

- northern Minnesota continues to face lingering drought issues in 2007. Some drought concerns for the 2007 growing season in northern Minnesota include:
 * increased wildfire risk
 * streams dropping below protected flow thresholds
 * low lake water levels and associated water access issues
 * ground water levels lowering in lagged response to precipitation deficits. Ground water levels will also respond to increased pumping pressures.
 * inadequate soil moisture conditions further impacting agriculture, especially forage crops
 * inadequate soil moisture conditions further stressing forest communities, making them more vulnerable to pests

NOTES FROM AROUND THE STATE

- none

UPCOMING DATES OF NOTE

- May 17: 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.crh.noaa.gov - National Weather Service Central Region Headquarters
http://www.drought.unl.edu - National Drought Mitigation Center
http://www.nass.usda.gov - USDA, National Agricultural Statistics Service
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.lwcb.ca/ - Lake of the Woods Control Board
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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