HydroClim Minnesota - July 2002

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 7/3/02


- June 2002 was one of the wettest months in Minnesota's history. June 2002 precipitation totals exceeded 10 inches in numerous communities of northwestern, north central, central, and southeastern Minnesota. Monthly totals surpassing 12 inches were reported in Norman, Mahnomen, Roseau, Lake of the Woods, Koochiching, and Goodhue counties. Precipitation departures from normal exceeded one half FOOT in many areas and one FOOT in some locales. When compared against historical June data, June 2002 precipitation totals ranked at or above the 99th percentile for nearly all of northwestern Minnesota, large areas of north central Minnesota, and some sections of northeastern, central, and southeastern Minnesota. In some northwestern Minnesota communities, June 9 and 10 rainfall alone exceeded one half of their normal ANNUAL precipitation.
- portions of northwestern and north central Minnesota experienced one of the most significant precipitation events in Minnesota's post-settlement history on June 9 and 10. While not unprecedented, the event was extraordinarily rare in its intensity and geographical extent. Rainfall totals for the 48-hour period beginning during the early-morning hours of Sunday, June 9 exceeded six inches over a broad multi-county area. Rainfall accumulations topped eight inches in portions of Norman, Mahnomen, Marshall, Kittson, Roseau and Koochiching counties. All of Lake of the Woods county fell within the eight inch contour. An incredible twelve inches of rain doused portions of Roseau, Lake of the Woods, and Koochiching counties. The largest rainfall report was a 14.55 inch total near Lake of the Woods on the Roseau/Lake of the Woods county border. Anecdotal reports of fifteen or more inches were received in some areas of Lake of the Woods county. 
- two weeks later on June 22 and 23, a broad swath of northern Minnesota received over four inches of rain. Rainfall totals topped six inches in portions of northwestern and northeastern Minnesota. For Mahnomen and Norman counties, some of the communities that had received six to eight inches of rain earlier in the month were drenched by another six to eight inch deluge.
- on June 21 and June 24 heavy rains fell on Wright county and surrounding areas. Rainfall totals of four to six inches fell during a relatively short period on the evening of June 24. This rain fell upon a landscape that was already saturated from a two to three inch dousing that occurred only three days earlier on June 21. Four-day rainfall totals exceeding seven inches were reported in sections of Wright, Mcleod, Meeker, Carver, and Hennepin counties.
- flooding rains were also reported on June 18 in portions of Faribault county, and June 20 and 21 in southeastern Rice and southern Goodhue counties.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://www.dnr.state.mn.us/climate/floods/2002.html , http://climate.umn.edu/doc/journal/flash_floods/ff020609-10.htm ,
http://climate.umn.edu/doc/journal/flash_floods/ff020622-23.htm ,
http://climate.umn.edu/doc/journal/flash_floods/ff020621-24.htm ,
http://climate.umn.edu/img/flash_floods/june2002prec.gif ,
http://climate.umn.edu/img/flash_floods/june2002dept.gif ,
http://climate.umn.edu/img/flash_floods/june2002rank.gif )
- June monthly temperatures were generally two to three degrees warmer than normal around the state. This marks the first time that monthly temperatures finished above normal since February. The last few days of June were sweltering. During this period, air temperatures climbed into the mid-90's and dew point temperatures rose above 70 degrees. The combination of hot and humid weather produced heat index values exceeding 100 degrees.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/heat020701.htm )


- growing season precipitation totals to date (April 1 - July 1) offer a mosaic of differing conditions across Minnesota. The excessive June rains pushed growing season totals above 175 percent of normal in northwestern and north central Minnesota, as well as sections of central and southeastern Minnesota. Conversely, rainfall totals for portions of extreme southwestern Minnesota and northeastern Minnesota are well below normal, with some communities receiving only one half of their normal April - June precipitation. In previously-dry west central and central Minnesota counties, the June rains were very beneficial and lifted growing season totals to near historical averages.
(see: http://climate.umn.edu/doc/weekmap.asp )
- as of July 2, the National Drought Mitigation Center - U. S. Drought Monitor shows that all Minnesota counties are free of any 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.
(see: http://www.drought.unl.edu/dm/monitor.html )
- the June 29 Palmer Drought Severity Index map from the Climate Prediction Center places all Minnesota counties 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 on June 30 that the state's topsoil moisture was 28% surplus, 63% adequate, 8% short, and 1% very short. Quantitative soil moisture measurements are rare. However, recent measurements from University of Minnesota research locations in southern Minnesota indicate that soil moisture values in those areas are well above historical averages. 
(see: http://www.nass.usda.gov/mn/cwmn.htm , http://swroc.coafes.umn.edu/Weather/Charts/Soil/2002/02_soil_water.html , http://climate.umn.edu/img/soil_moisture/wassm12.gif )
- the U.S. Geological Survey indicates that many river gaging stations in northwestern and north central Minnesota are showing new record high discharge values for the date. Elsewhere across the state, many stream discharge values are above the 75th percentile for the date. Stream flows in some rivers in northeastern, west central, central, and far southern Minnesota are near historical averages.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd , http://climate.umn.edu/dow/weekly_stream_flow/stream_flow_weekly.asp )
- the potential for wildfires is rated as moderate across much of northeastern Minnesota. The fire danger is rated low elsewhere around the state.
(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 except in far southeastern Minnesota. In southeastern Minnesota, the July precipitation outlook tilts towards above normal values. 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 shows no significant tendencies away from climatological probabilities. The July though September temperature outlook also shows no significant tendencies away from climatological probabilities.
(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, Minnesota River, and upper 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 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 are produced near the middle of each month. 
(see: http://www.crh.noaa.gov/ahps/index.html )


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- July 18, Climate Prediction Center releases 30/90 day temperature and precipitation outlooks 


http://climate.umn.edu - Minnesota Climatology Working Group
http://www.dnr.state.mn.us/ - Minnesota DNR
http://www.drought.unl.edu/ - National Drought Mitigation Center
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.nass.usda.gov/mn/cwmn.htm - Minnesota Agricultural Statistics Service
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey, Minnesota
http://www.dnr.state.mn.us/waters/programs/surwat_section/stream_hydro/productsf.html - Minnesota DNR Waters
http://www.dnr.state.mn.us/forestry/fire/ - Minnesota DNR Forestry
http://www.crh.noaa.gov/ahps/index.html - National Weather Service - Central Region Headquarters


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