HydroClim Minnesota - May 2010
A monthly electronic newsletter summarizing Minnesota's 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: May 5, 2010
What happened in April:
- April 2010 precipitation totals were below average in many Minnesota communities. It was particularly dry in northeastern Minnesota, in south central and southeastern Minnesota counties, and in a small portion of southwestern Minnesota. In these locations, April precipitation fell short of average by one inch to one and one-half inches. After a nearly snowless March, no Minnesota communities reported measurable snowfall in April. This is the only time in the modern record where all of Minnesota avoided measureable April snow.
[see: April 2010 Climate Summary Table | Snowless April]
- During the second half of March and the first half of April, precipitation was very light throughout Minnesota. The lack of rain and snow was an extraordinary piece of good fortune for communities involved in the late winter/early spring flood fight. The dry weather during the peak of the flood crest kept a serious situation from becoming far worse.
- The heaviest rainfall event of the month occurred during the early morning hours of April 13. Two to four inch rainfall totals were observed along a corridor from Willmar, to Hutchinson, to Carver.
[see: April 13 Rainfall Totals]
- Monthly mean temperatures for April 2010 were well above average across Minnesota. It was the second consecutive month of unseasonably warm temperatures. April monthly temperature averages were six to nine degrees above the historical mean, ranking April 2010 among the warmest Aprils of the modern record. Extreme temperature values for April ranged from a high of 85 degrees at various Minnesota locations on the 1st, to a low of 8 degrees at Babbitt (St. Louis County) on the 9th. Maximum temperature records were set on April 1st at various locations around the state.
[see: April 2010 Climate Summary Table | Record April 1 Warmth | Warm April]
Where we stand now:
- The late winter and spring has offered unusually warm temperatures and scant seasonal precipitation totals. Precipitation totals since mid-March are less than one and one half inch for nearly all of northeastern Minnesota. In many of these communities, mid-March through early-May precipitation totals are near, or below, all-time record low values.
[see: Dry and Warm Spring - 2010]
- The U. S. Drought Monitor, released on April 29, depicts Cook and Lake counties in northeastern Minnesota as undergoing Severe drought. Other north central and northeastern Minnesota counties are considered to be under the influence of Moderate drought. Portions of east central Minnesota are also depicted as experiencing Moderate drought. The situation in east central Minnesota is due to a prolonged period of below-average precipitation that began in June of 2008. The rest of Minnesota is without drought designation. The U. S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc) are based on several indicators.
[see: U.S. Drought Monitor]
- The U.S. Geological Survey reports that stream discharge values in many northern and eastern Minnesota watersheds are below the 10th percentile when compared with historical data for the date. Stream levels remain high in the upper Red River basin.
[see: USGS Streamflow | DNR Streamflow]
- The Lake Superior water level is down five to six inches from last year at this time and remains below the long-term average. Water levels on many northern, central, and east central lakes are below average. Water levels on some larger lakes and wetlands complexes in east central Minnesota lakes remain exceptionally low. White Bear Lake, on the Ramsey/Washington county border, is near its all-time record low level.
[see: Corps of Engineers Great Lakes Water Levels | White Bear Lake Water Level]
- As of May 2, the Minnesota Agricultural Statistics Service reports that topsoil moisture was 7% Very Short, 17% Short, 70% Adequate, and 6% Surplus. Spring planting and other fieldwork advanced rapidly during April. Planting completion dates will be among the earliest on record.
[see: Agricultural Statistics Service Crop Progress and Condition | U. of M. Southwest Research Center (Lamberton) Soil Moisture]
- Minnesota's lakes are free of ice. For many central and northern Minnesota locations, lake ice-out was ten to twenty days earlier than the long-term average. In some northern Minnesota lakes, lake ice-out was the earliest on record.
[see: Lake Ice-out Status]
- The potential for wildfires is currently rated by DNR Forestry as "moderate" in northeastern Minnesota and a few southeastern Minnesota counties. Fire danger is considered "low" elsewhere. This is a welcome change from a serious wildfire threat that existed throughout much of March and April over large sections of Minnesota.
[see: Fire Danger Rating Map]
- The May precipitation outlook shows no significant tendencies away from climatological probabilities. 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: Climate Prediction Center 30-day Outlook | May Precipitation Normal Map]
- The May temperature outlook shows no significant tendencies away from climatological probabilities. Normal May high temperatures are in the low to mid-60s early in the month, rising to the low to mid-70s at month's end. Normal May low temperatures are in the mid-30s to near 40 to start the month and climb to the mid-40s to low 50s as the month ends.
[see: Climate Prediction Center 30-day Outlook | May Temperature Normal Map]
- The 90-day precipitation outlook for May through July shows a tendency towards above-normal conditions. The May through July temperature projection tilts towards below-average conditions across most of Minnesota.
[see: Climate Prediction Center 90-day Outlook]
- 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: National Weather Service North Central River Forecast Center]
From the author:
Notes from around the state:
Upcoming dates of note:
- May 20: 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 U of M Dept. 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://mndnr.gov/waters - Minnesota Department of Natural Resources, Division of Waters
- http://www.lre.usace.army.mil - US Army Corps of Engineers, Detroit District
- http://www.nass.usda.gov - USDA, National Agricultural Statistics Service
- http://www.mvp-wc.usace.army.mil - US Army Corps of Engineers, St. Paul District
- http://swroc.cfans.umn.edu - University of Minnesota Southwest Research and Outreach Center, Lamberton
- http://mndnr.gov/forestry - Minnesota Department of Natural Resources, Division of Forestry
- http://www.cpc.ncep.noaa.gov - National Weather Service, Climate Prediction Center
- http://www.crh.noaa.gov/ncrfc - National Weather Service, North Central River Forecast Center
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