HydroClim Minnesota - July 2001

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 7/6/01


- June precipitation totals varied widely across Minnesota. Some portions of south central and east central Minnesota reported above average June precipitation, whereas the northern one third of Minnesota finished the month one half inch to one inch below normal. Elsewhere, June precipitation was near the historical mean. Much of June's rain came from a sequence of powerful storms that buffeted many Minnesota communities over the period June 11-14. Cumulative precipitation totals for this period topped four inches in many areas. Tornadoes, severe thunderstorm winds, and hail accompanied the storms and caused significant damage. Following this unsettled period, the weather turned dry and precipitation totals were generally light for the final two weeks of the month.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/stormy010614.htm )
- June temperatures finished very close to historical averages. However, the near normal monthly means were the result of very warm month-end temperatures offsetting cool early June weather.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )


- as of July 2, growing season precipitation totals (beginning April 1) were more than 125 percent of normal across most of the state. Growing season precipitation totals exceeded 150 percent of normal in many Minnesota communities. Precipitation totals were near or above all-time records for April through June in sections of central, east central, and northeastern Minnesota. Scattered pockets of record breaking April through June precipitation totals could also be found in southern Minnesota. By contrast, April through June precipitation totals for portions of northwestern Minnesota were near to below historical averages.
(see: http://climate.umn.edu/doc/weekmap.asp )
- the June 30 Palmer Drought Severity Index (PDSI) depicts south central and central Minnesota as undergoing a "Very Moist Spell". East central, southwestern, and southeastern Minnesota communities were said to be experiencing an "Unusual Moist Spell". The remainder of Minnesota falls in the "Near Normal" category. The Palmer Drought Severity Index is used for assessing long-term meteorological conditions.
(see: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif )
- the Minnesota Agricultural Statistics Service reports that topsoil moisture as of Friday, June 29 was rated 18% surplus, 75% adequate, 7% short, and 0% very short. Crop conditions have improved across the state, however crops in sandy soils are beginning to show signs of moisture stress.
(see: http://www.nass.usda.gov/mn/cwmn.htm )
- stream flows in Minnesota are at their lowest values of the open water season, responding to the recent dry weather and the actively transpiring landscape. The U.S. Geological Survey indicates that flows for over one half of Minnesota's streams are now in the normal category (between the 25th and 75th percentile for the date). Over one third of Minnesota streams remain somewhat high, ranking above the 75th percentile for the date.
(see: http://water.usgs.gov/cgi-bin/daily_flow?mn )
- the potential for wildfires is low in most Minnesota counties. However, the fire danger is categorized as moderate to high in portions of northeastern Minnesota.
(see: http://www.dnr.state.mn.us/forestry/fire/ )


- the July precipitation outlook from the Climate Prediction Center shows no significant tendencies away from climatological probabilities. July precipitation normals range from three inches in the far northwest to just over four inches in south central and southeastern Minnesota. The July temperature outlook also shows no significant tendencies away from climatological probabilities. Normal July high temperatures are in the low to mid 80's. Normal July lows are around 60 degrees.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/seasonal_forecast.html )
- the 90-day precipitation outlook for July through September tilts towards above normal precipitation statewide. The July though September temperature outlook leans towards below normal conditions across Minnesota.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/seasonal_forecast.html )
- the National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River and Minnesota 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 climatological data. The climatological data are weighted by the 90 day outlooks for temperature and precipitation trends. The model output offers a complete range of probabilistic values of stream stage and discharge for numerous forecast points. The product offers 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 will be produced near the middle of each month. The AHPS service will be available for the Mississippi River Basin in the autumn of 2002.
(see: http://www.crh.noaa.gov/fgf/ahps/ahpsmain.htm for the Red River basin, http://www.crh.noaa.gov/mpx/ahps/ for the Minnesota River basin)


- during the final week of June, much of the state experienced five consecutive days of maximum temperatures of 90 degrees or higher. There was somewhat of a media frenzy about the "heat wave". It is the responsibility of this Office to help our customers position weather conditions within the context of history. We gently reminded callers that maximum temperatures of 90 degrees or greater are common in southern and western Minnesota. In fact, the Twin Cities metropolitan area averages 15 days per year where the temperature reaches the 90 degree mark. However, many of the summers of the past decade were lacking hot spells of weather. Our climate memories being somewhat short, assimilated this behavior as the "norm". The moral of the story ... when researching, managing or monitoring natural systems where climate is a factor, don't trust your memory to define climatic benchmarks. Please allow us to help you to determine what is typical vs. atypical, probable vs. improbable; and to place the climate conditions in question in proper historical and spatial perspective.


- from the University of Minnesota - Southern Research and Outreach Center, Waseca

Rainfall in April-June totaled 16.99 inches or 6.26 inches above normal. This compares to 15.6, 15.8, 11.9 inches, respectively, in 2000, 1999, and 1998. Consequently, soil erosion has been horrendous again this year. Large gullies and deltas of settled, eroded soil can be found throughout the area. Conservation practices including grassed waterways, buffer strips, less tillage, and fewer acres of soybeans on the more erodible soils, will need to be implemented if we are to continue to have some of the most productive soils in the world. Continuing at the present pace will mean that future generations will only be able to read in books about the soil productivity the present generation has enjoyed. Our rich, black, deep and uniform soils will only be a memory of the past, if this rampant erosion is not controlled.


- July 12, Climate Prediction Center releases 30/90 day temperature and precipitation outlooks


http://climate.umn.edu - Minnesota Climatology Working Group
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.nass.usda.gov/mn/ - Minnesota Agricultural Statistics Service
http://water.usgs.gov/cgi-bin/daily_flow?mn - U.S. Geological Survey, Minnesota
http://www.dnr.state.mn.us/forestry/fire/ - Minnesota Department of Natural Resources - Division of Forestry http://www.crh.noaa.gov/fgf - National Weather Service Forecast Office - Grand Forks
http://www.crh.noaa.gov/mpx - National Weather Service Forecast Office - Chanhassen


- University of Minnesota - Southern Research and Outreach Center, Waseca

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