|HydroClim Minnesota - July 2003
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 in June varied widely across Minnesota. Monthly precipitation totals topped historical averages by one to six inches over portions of northwestern, west central, central, and east central Minnesota. Elsewhere across Minnesota, rainfall was near to somewhat below normal. WHERE WE STAND NOW
- a multi-day onslaught of thunderstorm complexes brought extraordinarily heavy rainfall and severe weather to central and southern Minnesota for the period June 21 through June 25. The heavy rains led to numerous reports of damaging urban and rural flooding. In addition to the torrential downpours, the thunderstorms spawned tornadoes, damaging winds, and hail. A tornado devastated the city of Buffalo Lake in Renville county during the evening of June 24. Rainfall totals for the five-day period topped six inches along a 30 mile wide band stretching from Traverse county in west central Minnesota to Pine county in east central Minnesota. Total rainfall exceeded eight inches in some areas embedded within this swath. Rainfall amounts also surpassed six inches in some areas of Kandiyohi, Renville, Meeker, Wright, Sherburne, Hennepin and Chisago counties during the period. Much of the rain in central Minnesota fell within a 48 hour period between June 22 and June 24. In Minnesota, the historical probability of receiving eight inches of rain within 48 hours for a given location is less than one percent per year. The heaviest rain in southern and east central Minnesota fell within a 12 hour period on June 24-25. The historical probability of receiving six inches of rain within 12 hours for a given location is also less than one percent per year.
- June temperatures were slightly cooler than normal across Minnesota. The monthly average temperature for June was one to two degrees below the historical average for most Minnesota communities. Temperature extremes ranged from 94 degrees at Chaska on the 23th, to 25 degrees at Embarrass on the 1st.
- growing season precipitation totals to date (April 1 - July 7) are near to above normal across most of Minnesota. Growing season precipitation totals for much of northwestern Minnesota and most of the central one third of the state are 25 percent above historical averages. In some of these areas, growing season precipitation totals rank above the 95th percentile when compared with historical data for the April 1 - July 7 period. For portions of Pope, Douglas, Todd, Morrison, and Crow Wing counties, growing season precipitation ranks near or above all-time records for the April 1 - July 7 interval. Growing season precipitation totals in some areas of north central and northeastern Minnesota fall short of historical averages, but June rains improved the situation considerably.
- as of July 8, the National Drought Mitigation Center - U. S. Drought Monitor indicates that portions of north central and northeastern Minnesota are judged to be in the "D0 - Abnormally Dry" category. This designation is a remnant of the dry conditions which persisted from January 2002 through the spring of 2003. The remainder of Minnesota is free of drought designation. 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 July 4, the state's topsoil moisture was 21% surplus, 74% adequate, and 5% short.
- the U.S. Geological Survey indicates that stream discharge values for approximately two thirds of Minnesota's rivers rank between the 25th and 75th percentiles for the date. Stream flows for many rivers in central Minnesota rank above the 75th percentile for the date. In some of these areas, stream discharge ranks above the 90th percentile when compared with historical data for the date. Some low flow conditions remain in north central Minnesota, but the situation has improved significantly from the very low levels observed this spring.
- water levels on many Minnesota lakes and wetlands have rebounded from this past spring's low elevations. For some lakes located in central and east central Minnesota counties, water levels are unusually high.
- the potential for wildfires is rated by DNR Forestry as low throughout Minnesota.
(see: http://www.dnr.state.mn.us/forestry/fire/ )
- the July precipitation outlook from the Climate Prediction Center tilts towards above normal precipitation for the southern one half of Minnesota, but indicates no significant tendencies away from climatological probabilities for the northern half of the state. July precipitation normals range from just over three inches in far northwestern Minnesota, to over four inches in eastern sections of the state. The July temperature outlook leans towards below normal values in the southern one third of the state, but shows no significant tendencies away from climatological probabilities elsewhere in Minnesota. Normal July high temperatures are in the low to mid 80's. Normal July lows are around 60 degrees.
- the 90-day precipitation outlook for July through September shows no significant tendencies away from climatological probabilities. The July though September temperature outlook also indicates no significant 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. A hydrologic model is initialized using the current conditions of stream flow and soil moisture across a basin. The model is allowed to run into the future with multiple scenarios using more than 30 years of historical climatological data. The climatological data are weighted by 90-day climate outlooks for temperature and precipitation trends. Model output offers a complete range of probabilistic values of stream stage and discharge for numerous forecast points. The product provides a risk assessment tool which can be used in long-range planning decisions involving flooding or low flow concerns. These products are part of the National Weather Service's Advanced Hydrologic Prediction Service (AHPS) and are produced near the middle of each month.
FROM THE AUTHOR
NOTES FROM AROUND THE STATE
- noneUPCOMING DATES OF NOTE
- July 17, 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
- Minnesota Agricultural Statistics Service
http://mrcc.sws.uiuc.edu/ - Midwestern Regional Climate Center
http://swroc.coafes.umn.edu/ - University of Minnesota Southwest Research and Outreach Center, Lamberton
- U.S. Geological Survey, Minnesota
- Minnesota DNR Division of Waters
- Minnesota DNR Division of Forestry
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.crh.noaa.gov/ahps - National Weather Service, Central Region Headquarters
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