HydroClim Minnesota - January 2007

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 1/3/07

WHAT HAS HAPPENED

- December 2006 precipitation totals were above average in most Minnesota locations. December precipitation topped the historical normal by one half inch to one inch in many locales. Because a great deal of December's precipitation fell in the form of rain, December snowfall totals throughout Minnesota were well below historical averages. Much of Minnesota experienced a "brown" Christmas. It was the first time in Duluth's climate record that no snow was reported on the ground on the morning of December 25.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )
- the most significant precipitation event of December was caused by a large, slow-moving storm system that ambled through the Upper Midwest on New Year's Eve Day. The storm dropped large amounts of precipitation in the form of rain, freezing rain, and snow. Precipitation totals topped one inch in many southern and eastern Minnesota communities. Elsewhere, precipitation totals were greater than one half inch. Were it not for this end-of-month event, most of Minnesota was destined for yet another dry month.
(see: http://climate.umn.edu/doc/journal/snow061231.htm )
- monthly mean temperatures for December 2006 were much warmer than average throughout Minnesota. Average temperatures for the month ranged from nine to twelve degrees above normal. The first week of the month was quite chilly, with temperatures averaging about ten degrees below average. With abruptness common to Minnesota, the weather pattern changed. For the final three weeks of the month, temperatures were consistently and substantially warmer than average. Extreme values for the month ranged from 67 degrees at Browns Valley on the 9th, to -18 degrees at Fosston on the 7th.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )

WHERE WE STAND NOW

- the snow depth map to be prepared on January 4 will show that northeastern Minnesota counties and portions of far northwestern Minnesota report six or more inches of snow on the ground. Snow depths exceeding 12 inches are found along the North Shore highlands. In southern and central Minnesota, three or more inches of snow cover a sixty mile-wide swath that extends from near Fairmont, through the western metropolitan area, and northward to Duluth. Much of the western one half of Minnesota, and portions of central and north central Minnesota, have little or no snow cover. Throughout Minnesota, snow cover remains below the historical median for this date.
(see: http://climate.umn.edu/doc/snowmap.htm )
- dryness has been entrenched across northern and central Minnesota for nearly eight months. Eight-month precipitation totals have deviated negatively from historical averages by more than six inches across most of the northern one half of Minnesota.
- the National Drought Mitigation Center (NDMC) - U. S. Drought Monitor to be released on January 4 will continue to indicate that many northern Minnesota counties remain in the "Extreme Drought" or "Severe Drought" categories. The northern reaches of the Red River Valley are depicted in the "Moderate Drought" or "Abnormally Dry" classification. The "Abnormally Dry" polygon covers much of central and southern Minnesota. The NDMC index is a blend of science and subjectivity where intensity categories are based on several indicators.
(see: http://www.drought.unl.edu/dm/monitor.html )
- the end-of-year rain/snow event somewhat improved the topsoil moisture situation in locations where partially frozen soils were receptive to infiltration. Nonetheless, with the absence of significant fall recharge, Minnesota's soils will rely heavily upon early spring rains to bring moisture levels up to sufficient levels. (see: http://mcc.sws.uiuc.edu/cliwatch/drought/moisture.htm ) - stream discharge in northern Minnesota watersheds remains low. Mississippi River flow conditions are very low due to long-term precipitation deficits in the headwaters area.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd )
- lake levels are very low in northern and central Minnesota. Some northern Minnesota lakes are at their lowest levels in many years. Lake Superior is approaching its lowest January water level in 80 years.
(see: http://www.dnr.state.mn.us/lakefind/index.html , http://www.lre.usace.army.mil/_kd/Items/actions.cfm?action=Show&item_id=3886&destination=ShowItem )
- soil frost depths are generally less than 12 inches. Soils in areas where snow can be trapped (turf grass surfaces, forests, and swamps) have even less frost. Historically, soil frost reaches maximum depth in late February.
(see: http://climate.umn.edu/doc/observatory.htm , http://www.mvp-wc.usace.army.mil/projects/reservoirs.shtml )
- due to the mild December weather, ice thickness on Minnesota's lakes is highly variable and ice safety is marginal. Those venturing onto the state's water bodies should utilize caution and common sense.
(see: http://www.dnr.state.mn.us/enforcement/co_report/index.html )

FUTURE PROSPECTS

- the January precipitation outlook from the Climate Prediction Center indicates no significant tendencies away from climatological probabilities across Minnesota. January precipitation normals range from near one half inch in western Minnesota to just over one inch in eastern sections of the state. The median snow cover at the end of January ranges from near 5 inches in the southwest Minnesota, to over 15 inches on the ground in northeastern Minnesota (greater than 24 inches in the Lake Superior highlands).
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/precip/precip_norm_01.htm )
- the January temperature outlook leans heavily towards above-normal conditions throughout Minnesota. Normal January high temperatures range the low-teens in the north to near 20 in the south. Normal January lows range from near minus 10 degrees in the far north to the single digits above zero in southern Minnesota.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/30day , http://climate.umn.edu/img/normals/temp_norm_adj/temp_norm_adj_01.htm )
- the 90-day precipitation outlook for January through March indicates no significant tendencies away from climatological probabilities across Minnesota. The January through March temperature outlook indicates a considerable tilt towards above-normal conditions throughout the state.
(see: http://www.cpc.ncep.noaa.gov/products/predictions/90day/lead01/index.html )
- the National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. These products are part of the National Weather Service's Advanced Hydrologic Prediction Service (AHPS).
(see: http://www.crh.noaa.gov/ncrfc/ )

FROM THE AUTHOR

- none

NOTES FROM AROUND THE STATE

- Dr. Mark Seeley of the University of Minnesota prepared the following annual climate synopsis for 2006:

For the Twin Cities area January of 2006 was the warmest since 1846, and 2nd warmest all-time. Freeze-thaw cycles numbered 30 or more in many places and caused significant potholes and pavement damage for Mn/DOT to repair.

It was a snowy March for most of the state. For many it was the snowiest month of the year, including the Twin Cities which reported 20.4 inches, much of which came during the mid month high school basketball tournament sessions.

The warmest July statewide since 1936, amplified a rapid onset of drought in central and northern Minnesota counties. Many locations recorded their first 100 degree F maximum temperatures in over 10 years, but it was abnormally warm nights that made the month so hot. Many nighttime lows never fell below 75 F. In the end July 2006 was the 4th warmest all-time in the Twin Cities area, and 5th warmest statewide.

A severe hail storm brought widespread damage across southern Minnesota counties on August 24th. Both New Prague and Northfield reported baseball size hail and severe damage to motor vehicles, many of them on car sales lots.

A tornado that formed very rapidly struck Rogers (northern Hennepin County) on the evening of September 16th. Many homes were damaged and a child was killed. A total of only 21 tornadoes were reported in the state this year.

Drought left its mark on Minnesota during 2006 and much of the state remains in its grasp, as central and northern counties are still marked as Severe to Extreme Drought by the USDA and National Weather Service. Lake levels are very low, including Lake Superior, river flows are low, and stored soil moisture in many areas is the lowest since the drought of 1988 in some areas.

UPCOMING DATES OF NOTE

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

WEB SITES FEATURED IN THIS EDITION

http://climate.umn.edu - Minnesota Climatology Working Group
http://www.drought.unl.edu - National Drought Mitigation Center
http://mcc.sws.uiuc.edu - Midwestern Regional Climate Center
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey
http://www.dnr.state.mn.us/waters - Minnesota Department of Natural Resources, Division of Waters
http://www.lre.usace.army.mil - US Army Corps of Engineers, Detroit District
http://www.mvp-wc.usace.army.mil - US Army Corps of Engineers, St. Paul District
http://www.dnr.state.mn.us/enforcement - Minnesota Department of Natural Resources, Enforcement Division
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://www.crh.noaa.gov/ncrfc - National Weather Service North Central River Forecast Center - Chanhassen

ACKNOWLEDGEMENTS

- none

To subscribe or unsubscribe to "HydroClim" please notify Greg Spoden:
gspoden@umn.edu or greg.spoden@dnr.state.mn.us
651-296-4214

Contributions of information and suggestions are welcome!