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 1/09/02

WHAT HAS HAPPENED

- December precipitation was below historical averages across nearly all of Minnesota. Precipitation totals ranged from one quarter inch to one and one quarter inches. These values fell short of the historical norm by approximately one half inch in most locations. A complex of thunderstorms dropped nearly a half inch of rain on December 5 over far southeastern Minnesota. December thunderstorms are rare, but not unprecedented in Minnesota. Much of Minnesota was rescued from a brown Christmas by a December 22 snow event that deposited two to six inches of snow across much of the state.
(see: http://climate.umn.edu/cawap/monsum/monsum.asp )
- keeping with a pattern established in November, temperatures in December finished 8 to 11 degrees above the historical mean across the state. Many southern Minnesota communities set all-time maximum temperature records on December 5. The Twin Cities reached 63 degrees on that date. During the month of December, the Twin Cities also set a record for the longest streak of above normal average daily temperatures. For the 57-day period from October 28 through December 23, the Twin Cities International Airport reported above normal daily average temperatures. This streak exceeded the previous record streak by 15 days. 
(see: http://climate.umn.edu/cawap/monsum/monsum.asp , http://climate.umn.edu/doc/journal/warm011205.htm ,
http://climate.umn.edu/doc/journal/warmstreak01.htm )


WHERE WE STAND NOW

- (repeated from last month): heavy late November rainfall and snowfall brought relief to areas affected by precipitation deficits established during the later part of the 2001 growing season. Growing season precipitation totals in southwestern, central, east central Minnesota counties were significantly below normal, and the lack of soil moisture reserves available for the 2002 growing season was a concern. However, because the considerable November precipitation fell before soil freeze-up, the soil moisture profile has been amply recharged. While the soil laid first claim to the November precipitation, water levels in surface hydrology systems such as lakes, rivers, and wetlands rose in response to the rain and snow melt.
- snow depths as of this writing have diminished to near-zero across much of the southern of half of Minnesota. In northern Minnesota, snow depths are generally less than six inches. Tomorrow's (January 10) snow depth ranking map will likely indicate that snow depths will rank near or below the fifth percentile for the date in most Minnesota counties.
(see: http://climate.umn.edu/doc/snowmap.htm )
- as of January 3, the National Drought Mitigation Center shows Minnesota to be 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://enso.unl.edu/monitor/monitor.html )
- the January 5 Palmer Drought Severity Index (PDSI) from the Climate Prediction Center depicts most Minnesota counties in the "near normal" category. East central Minnesota counties are placed in the "Moderate Drought" category. However, I believe this designation to be erroneous. The error may arise from data quality issues that will be repaired in future renditions. 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 U.S. Geological Survey indicates that all Minnesota streams (where winter reporting is possible) are in the normal to above normal categories for the date. Nearly one half of these stations report stream discharge above the 90th percentile for this time of year.
(see: http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd )
- the mild temperatures of November and December delayed the formation of ice on many large Minnesota lakes until mid-December. While historical lake freeze-up data are sparse, anecdotal reports indicate that lake ice formation dates this season were many weeks later than average, and among the latest ever. This season's "ice-in" dates were similar to those reported in December 1998, when balmy weather was also common during the early winter. While all of Minnesota's lakes are currently ice-covered, ice thickness and integrity are not at typical January conditions.


FUTURE PROSPECTS

- the January precipitation outlook from the Climate Prediction Center shows no significant tendencies away from climatological probabilities. January precipitation normals range from one half inch in western Minnesota to near 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). The January temperature outlook also shows no significant tendencies away from climatological probabilities. 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/multi_season/13_seasonal_outlooks/color/seasonal_forecast.html )
- the 90-day precipitation outlook for January through March shows no significant tendencies away from climatological probabilities. The January though March 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 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/ahps/index.html )


FROM THE AUTHOR

- none


NOTES FROM AROUND THE STATE

UPCOMING DATES OF NOTE

- January 17, Climate Prediction Center releases 30/90 day temperature and precipitation outlooks 
- January 29, Interagency Flood Planning Coordination Meeting, Corps of Engineers - St. Paul


WEB SITES FEATURED IN THIS EDITION

http://climate.umn.edu - Minnesota Climatology Working Group
http://enso.unl.edu/ndmc/ - National Drought Mitigation Center
http://www.cpc.ncep.noaa.gov - Climate Prediction Center
http://water.usgs.gov/cgi-bin/dailyMainW?state=mn&map_type=weekd - U.S. Geological Survey, Minnesota
http://www.crh.noaa.gov/ahps/index.html - National Weather Service - Central Region Headquarters


ACKNOWLEDGEMENTS

Contributions of information and suggestions are welcome!