HydroClim Minnesota - May 2009
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
What happened in April:
- April 2009 was a dry month across nearly all of Minnesota. Most Minnesota locales reported April precipitation totals that fell short of the historical average by one-half inch to one inch. A few far-northern Minnesota communities reported above-normal April precipitation, thanks mostly to an early-spring snowstorm that continued from March 31 into April 1.
[see: April 2009 Climate Summary Table]
- Monthly mean temperatures for April 2009 were near historical averages across Minnesota. Extreme temperature values for April ranged from a high in the low 90's in many southern Minnesota locales on the 23rd and 24th, to a low of 9 degrees in Fergus Falls on the 3rd. High temperature records were tied or broken in some southern Minnesota communities on the 23rd and 24th.
[see: April 2009 Climate Summary Table]
- Major flooding began in the latter half of March and continued through April in the Red River basin and a few other Minnesota watersheds. In the Red River basin, minor to moderate flooding is still underway as of this writing. The 2009 flooding event was remarkable for its early onset, its unparalleled magnitude at some reporting stations, and for its extended duration. The flood was responsible for extensive damage to public infrastructure and private property, and led to a federal disaster declaration. Fortunately, dry April weather and a favorable melt pattern mitigated the situation somewhat.
[see: National Weather Service - Grand Forks]
Where we stand now:
- The U. S. Drought Monitor, released on April 30, classified some southeastern Minnesota counties in the D0 - Abnormally Dry category. Portions of east central and southeastern Minnesota were placed in the D1 - Moderate Drought classification. Precipitation during the last half of 2008 was five to eight inches short of average for many southeastern Minnesota communities. The U. S. Drought Monitor index is a blend of science and subjectivity where intensity categories are based on several indicators.
[see: U.S. Drought Monitor]
- The U.S. Geological Survey reports that stream discharge values are high in the Red River basin and along the upper Mississippi River. Stream flow measurements in these areas are above the 90th percentile when compared with the historical distribution for this time of year. Stream discharge values in southeastern Minnesota are below the historical median for the date.
[see: USGS Streamflow | DNR Streamflow]
- The Lake Superior water level is up three inches from last year at this time but remains below the long-term average. Levels on inland lakes in Minnesota's drought areas are low. In some cases, east central Minnesota lake levels are similar to those observed during the droughts of 2006 and 2007.
[see: Corps of Engineers Great Lakes Water Levels]
- The Minnesota Agricultural Statistics Service reports that as of May 3, topsoil moisture was 1% "Very Short", 10% "Short", 66% "Adequate", and 23% "Surplus". Surplus soil moisture conditions are found throughout the Red River basin.
[see: Agricultural Statistics Service Crop Progress and Condition]
- Some sections of Lake of the Woods, and a handful of deep lakes in Cook County remain ice covered. Lakes in the southern one-quarter of Minnesota lost their ice during the third week of March, roughly five days earlier than the historical average. Ice-out dates for lakes in central Minnesota were close to the historical average. For the northern one-third of the state, lake ice-out dates were three to five days later than average.
[see: Lake Ice-Out Status]
- The potential for wildfires is currently rated by DNR Forestry as "moderate" across most of the northern two-thirds of Minnesota. The wildfire danger rating is "low" in the southern one-third of Minnesota. These conditions can change rapidly in response to warm, sunny, and windy weather. Historically, 80 percent of all wildfires in Minnesota occur during April and May. [see: Fire Danger Rating Map]
- The May precipitation outlook tilts towards heavier than normal rainfall. 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 indicates a tendency towards below-normal conditions. 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: Climate Prediction Center 30-day Outlook | May Temperature Normal Map]
- The 90-day precipitation outlook for May through July leans towards above-normal conditions across nearly all of Minnesota. The May through July temperature projection tilts towards below-normal conditions across most of Minnesota with the exception of northeastern Minnesota where the outlook shows no significant tendencies away from climatological probabilities.
[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 River Forecast Center]
From the author:
Notes from around the state:
Upcoming dates of note:
- May 21: 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.crh.noaa.gov/fgf - National Weather Service, Grand Forks Forecast Office
- 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://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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