Minnesota Drought Situation Report - October 4, 2007

Announcement: Due to improving conditions, and a less drought-sensitive time of year, this situation report will be updated monthly instead of weekly during the autumn and winter. The narrative will be prepared on the first Thursday of each month. The document will be revised more frequently if notable changes in the drought situation occur.

Drought Monitor - October 2, 2007
Drought Monitor Map
Drought Monitor Legend

Drought Status:
The latest U. S. Drought Monitor (see map at right) shows continued improvement in drought conditions for many Minnesota counties (view previous week's map). Heavy rains in central Minnesota last week eliminated Extreme Drought designations and substantially decreased the geographic extent of the Severe Drought polygon. This week's drought monitor presents worsening drought conditions in northwestern Minnesota. The drought classification in the northern Red River Valley was downgraded from Abnormally Dry to Moderate Drought.

The drought situation in north central and northeastern Minnesota is the result of a very dry 2006, a snow-sparse 2006-2007 winter, and dry 2007 mid-summer weather. The drought situation in the central third of Minnesota is due to an extremely dry 2007 growing season (see: 12-week U.S. Drought Monitor animation). The worsening situation in northwestern Minnesota is a reflection of very dry weather in late summer and early autumn 2007.

The U. S. Drought Monitor index is a blend of science and subjectivity where intensity categories are based on several indicators.

Weekly Precipitation Map Last week's weather:
Rainfall totals for the week ending Monday morning, October 1 were moderate to heavy across all but northwestern Minnesota. Weekly rainfall totals in excess of three inches were common in southeastern Minnesota (see map at left). One to three inch totals were reported in many central Minnesota communities. Long-term average rainfall rates are now around one half inch per week. Temperatures last week were warm, averaging four to six degrees above normal. Temperatures in nearly all Minnesota locations climbed into the 80's at least once last week.

Summer Dryness (June 5 - October 1):
Dryness was entrenched across northern and central Minnesota for much of the summer. September rains significantly improved the situation in many areas. However, rainfall for the seventeen-week period from June 5 through October 1 totaled less than ten inches for some locations in west central and central Minnesota (see map below). In these areas, rainfall totals for the period were four or more inches short of the historical average (see map below). When compared with historical rainfall totals for the same seventeen-week time frame, 2007 values ranked at or below the 10th percentile (one year in ten occurrence) in some counties (see map below). The period from May through September is historically the wettest time of the year in Minnesota. Long-term average rainfall rates during the heart of the summer are around one inch per week. Very dry weather, occurring during a time of year when ample rain is typical, leads to the rapid intensification of drought. The lack of precipitation, along with very high evaporation rates, produced deteriorating crop conditions, lower stream flows and lake levels, and increased wildfire danger.

June 5 to October 1 2007 Precipitation June 5 to October 1 2007 Precipitation Departure Map June 5 to October 1 2007 Precipitation Ranking Map

Sector briefs:

More drought information resources are found at http://climate.umn.edu/doc/journal/drought_information_resources.htm.

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URL: http://climate.umn.edu/doc/journal/drought_situation_report_2007_071004.htm
Last modified: October 4, 2007