HydroClim Minnesota - December 2011
A monthly electronic newsletter summarizing Minnesota's climate conditions and the resulting impact on water resources. Distributed on the Wednesday following the first Monday of each month.
State Climatology Office - DNR Division of Ecological and Water Resources, St. Paul
distributed: December 6, 2011
What happened in November 2011:
- November 2011 was another dry month across Minnesota. This marked the fourth consecutive month of widespread precipitation shortfalls. For many locations, November precipitation totals failed to reach one-half inch. In nearly all counties, monthly precipitation fell short of the historical average by one to one and one-half inches. In some locales, it was among the driest Novembers of the modern record.
- Monthly mean temperatures for November 2011 were warm, topping the historical average by four to six degrees across Minnesota. Preliminary data indicate that November 2011 will rank among the warmest Novembers in the historical record. Extreme temperature values for November ranged from a high of 67 degrees F at various southeast and east central Minnesota reporting stations on the 1st and again on the 12th, to a low of -6 degrees F at Hallock (Kittson County) on the 17th and Madison (Lac Qui Parle County) on the 20th. Maximum temperature records were set at numerous locations on November 23 and 24.
Where we stand now:
- Significant precipitation shortfalls were reported across Minnesota over the period from late-July through November. Precipitation totals for the period were less than three inches in many southern Minnesota counties, a negative departure from the long-term average of five to nine inches. When compared with the same period in the historical database, the late-summer through autumn 2011 precipitation totals rank among the lowest on record. Similar patterns are evident when looking at precipitation data for only the meteorological autumn (September through November). A significant portion of Minnesota reported autumn precipitation deficits of five or more inches. For a large section of the southern one-third of Minnesota, this autumn was the driest on record.
- The U. S. Drought Monitor, released on November 29, depicts every Minnesota county as experiencing some level of drought. Large sections of north central and northeast Minnesota are said to be undergoing Severe Drought or Moderate Drought. Stream flow and lake levels in those areas are very low due to the ongoing impact of precipitation deficits accrued during the 2010 growing season and spotty rainfall this season. The Drought Monitor also places much of southern Minnesota in the Severe Drought or Moderate Drought categories. Late-summer and autumn precipitation has been minimal across the southern one-third of Minnesota. The U. S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc) are based on several indicators.
- Northeast Minnesota counties report four to six inches of snow cover as of this writing. A narrow stripe of four-inch snow cover also extends through a few southeast Minnesota counties. Elsewhere in Minnesota, snow depths are generally one to three inches, with some locations reporting a snow-free landscape. In nearly all locations, the present snow depth is below the historical median.
- The Lake Superior water level is near its elevation of a year ago, but down 11 inches from the long-term seasonal average. The water level on White Bear Lake (Ramsey/Washington county border) remains quite low. The White Bear Lake elevation is up by roughly one-half foot after reaching an all-time record low level mark in November 2010. Lake levels in far northern Minnesota are very low when compared with historical averages, especially lakes along the Canadian border.
- In their final report of the season (November 7), the Minnesota Agricultural Statistics Service reported that topsoil moisture was 28% Very Short, 43% Short, 29% Adequate, and 0% Surplus across the state. Dry soils made autumn tillage very difficult in many areas and heightened concerns about the soil moisture profile for next growing season. Late-autumn conditions act as a predictor of the soil moisture situation entering the 2012 growing season.
- The upper layer of the soil profile is frozen to a few inches in most Minnesota locales.
- Many Minnesota lakes and rivers are now ice covered. Sustained sub-freezing temperatures in early December enhanced ice development. Ice conditions are highly variable. Lake and river ice is NEVER completely safe for walking or driving.
- The December precipitation outlook presents an equal likelihood of below-normal, near-normal, or above-normal conditions across Minnesota. December precipitation normals range from around one-half inch in western Minnesota to over one and one-quarter inches in eastern sections of the state. The median snow cover at the end of December ranges from under 5 inches in southwest counties, to over 10 inches on the ground in northeast Minnesota (20 inches in the Lake Superior highlands).
- The December temperature outlook also offers an equal likelihood of below-normal, near-normal, or above-normal conditions throughout the state. Normal December high temperatures are in the mid 20s to near 30 to start the month, dropping to the mid-teens to near 20 by month's end. Normal lows are around 10 degrees early in the month, falling to the mid-single digits above and below zero by late December.
- The 90-day precipitation outlook for December through February tilts towards above-normal snowfall in Minnesota, especially in northwest counties. The December through February temperature projection indicates a tendency towards below-normal conditions throughout Minnesota, particularly in the northern one-half of the state.
From the author:
Contributions of information and suggestions are welcome!
Last modified: July 9, 2015