|HydroClim Minnesota - September 2005
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
WHAT HAS HAPPENED
- rainfall varied widely across Minnesota in August 2005. Northeastern Minnesota was extremely dry, with precipitation totals falling short of historical averages by two or more inches. August rainfall totals in sections of Carlton, St. Louis, and Lake counties were among the lowest on record. By contrast, areas of northwestern, west central, south central, and southeastern Minnesota reported very heavy August rainfall. The above normal precipitation in these areas was the result of a few, very intense, rainfall events.
- dry July 2005 conditions experienced throughout Minnesota persisted into August in north central, northeastern, and east central Minnesota. Two-month rainfall totals for July and August were well below historical averages in these areas. Rainfall deficits exceeded five inches in portions of east central and northeastern Minnesota. When compared with other July plus August rainfall totals in the historical database, July plus August 2005 rainfall totals ranked among the lowest on record in some locales. The precipitation shortfalls led to low stream flows and increased wildfire danger in many communities.
- two heavy rain storms of note impacted Minnesota during August 2005. On August 17 and 18, intense thunderstorms dropped more than five inches of rain on portions of Cottonwood, Jackson, Watonwan, Martin, and Blue Earth counties. Nearly eight inches of rain fell in a small portion of south central Watonwan county. On August 25 and 26, severe thunderstorms produced hail, high winds, and torrential rain over a multi-county area of west central Minnesota. Rainfall totals topping five inches were reported in sections of Douglas, Pope, Stearns, Swift, Kandiyohi, and Chippewa counties. Over eight inches of rain was recorded in northwestern Kandiyohi county during this event.
- August 2005 monthly mean temperatures were near average in most areas. The very warm temperatures of June and July persisted into the first week of August. Temperatures then moderated for the remainder of August, leading to a rather remarkable stretch of pleasant weather. The temperature extremes for August ranged from 98 degrees at Ortonville on the 8th, to 29 degrees at Embarrass (St. Louis county) on the 23rd.
WHERE WE STAND NOW
- growing season precipitation totals to date (April 1 - early September) show substantial spatial variation across Minnesota. In general terms, seasonal precipitation totals are well above average in western Minnesota counties, and well below average east central and northeastern counties. In some sections of northwestern, west central and southwestern Minnesota, seasonal precipitation totals are greater than 125 percent of normal. Seasonal rainfall totals in some of these areas are near, or above, all-time record values to date. By contrast, rainfall across nearly all of northeastern Minnesota has been less than 80 percent of normal precipitation for the growing season.
- as of August 30, the National Drought Mitigation Center (NDMC) - U. S. Drought Monitor indicated that portions of east central and northeastern Minnesota are judged to be in the "D0 - Abnormally Dry" category. Some sections of northeastern Minnesota are deemed to be in the "D1 Drought - Moderate" classification. All other Minnesota counties are free of drought designations. The NDMC index is a blend of science and subjectivity where intensity categories are based on six key indicators and numerous supplementary indicators.
- the Minnesota Agricultural Statistics Service reports that as of September 2, the state's topsoil moisture was 4% very short, 13% short, 75% adequate, and 8% surplus.
- the U.S. Geological Survey indicates that stream discharge values vary significantly across Minnesota. Stream flows in east central and northeastern Minnesota are low, falling below the 10th percentile for the date in some locations. Stream flows in west central and northwestern Minnesota remain high, topping the 90th percentile for the date in many spots.
- the potential for wildfires is rated by DNR Forestry as "High" across northeastern Minnesota. The fire danger is "Moderate" over sections of north central Minnesota. A "Low" fire danger rating is posted for all other areas of Minnesota.
- the September precipitation outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. September precipitation normals range from near two inches in far western Minnesota to around three and one half inches in eastern sections of the state.
- the September temperature outlook also shows no significant tendencies away from climatological probabilities. Normal September high temperatures are in the mid-70's to start the month, dropping to the low to mid-60's by month's end. Normal lows are in the mid-50's early in the month, falling to around 40 by late September.
- the 90-day precipitation outlook for September through November indicates no significant tendencies away from climatological probabilities across Minnesota. The September through November temperature outlook also shows no tendencies away from climatological probabilities.
- 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/ahps/ESPMAPS )
FROM THE AUTHOR
NOTES FROM AROUND THE STATE
- noneUPCOMING DATES OF NOTE
- September 15, Climate Prediction Center releases 30/90 day temperature and precipitation outlooksWEB SITES FEATURED IN THIS EDITION
http://climate.umn.edu - Minnesota Climatology Working Group
http://www.drought.unl.edu - National Drought Mitigation Center
http://www.nass.usda.gov/mn/ - Minnesota Agricultural Statistics Service
- U.S. Geological Survey
- Minnesota Department of Natural Resources, Division of Forestry
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.crh.noaa.gov/ncrfc/ - National Weather Service, North Central River Forecast Center
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