The Climate Prediction Center (CPC) has updated the seasonal outlooks for the United States which include the winter months of December 2011 through February 2012. With a La Niña continuing to slowly intensify in the equatorial Pacific, the outlook for the northern plains calls for an increased likelihood of colder and wetter conditions during the December through February period. Based on the data from the CPC, La Niña usually results in an enhanced risk of colder conditions across eastern North Dakota and northwestern Minnesota. Precipitation is less well defined, although there is a slightly enhanced risk for wetter than average conditions across eastern North Dakota and northwest Minnesota. The entire nation may be viewed here.
What are the implications for temperatures? Below are the average monthly temperatures for the Grand Forks Area* and Fargo Area* for December, January and February. (These values represent a climatological average over a 30 year period.) As an example the average temperature during December in the Grand Forks area would be 12.0 degrees Fahrenheit. Over the past 30 years, the monthly December temperature has varied considerably, as is typical in any season. Statistically, tthe "normal range" can be as low as 4.9 degrees Fahrenheit or as high as 19.0 degrees Fahrenheit, yet still be considered "normal". The CPC Outlook indicates there is an enhanced risk the temperatures during the December - February time period will average below the lower values displayed.
|Grand Forks Area||Fargo Area|
What does this mean in terms of snowfall? The "average" snowfall across the Valley and Lakes region can differ significantly from one location to the next. Climatological "averages" vary from 45 to 55 inches in the Devils Lake Basin, to 55 to 65 inches in the Red River Valley and points east. (These values represent a climatological average over a 30 year period.) Snowfall is extremely variable in any given winter season, as history shows. It's not uncommon for part of the region to see repeated significant snows making for a heavy snowfall season, while other relatively nearby areas see much less. Therefore the outlooks represent the most likely departure from long term averages over on a regional scale.
Below are tables for the Fargo Area* and Grand Forks Area* with the "average" Winter snowfall for the past 30 years. Included are the statistical limits that one could consider a normal range.
|Grand Forks Area||Fargo Area|
As an example, the 30 year average snow-fall for the Fargo Area* is 49.6 inches, with an expected variation of 21.8 inches. That means in any given year the Fargo Area snowfall should range between 27.8 and 71.4 inches. That would be a "normal range". These station's record may include data from more than one, possibly incompatible, locations. It reflects the longest available record for the stations listed. Snowfall in inches, July 1 through June 30th.
So far this fall season, temperatures across the Red River Valley have been warmer than normal, with precipitation showing the usual variances. Across much of our region, conditions have varied significantly, with most folks experiencing significantly drier than average conditions. Wetter than average conditions have been observed across portions of the far northern Red River Valley so far this fall. Generally speaking, a pattern of generally drier and warmer weather is typical of La Niña affected fall seasons.
Click here for the NOAA National Top News article "U.S. dealt another La Niña winter but ‘wild card’ could trump it"
Additional details will be available as we progress through the fall season and atmospheric conditions become established.
December 2011 - February 2012 Probabilistic Temperature Outlook. Courtesy NOAA/Climate prediction Center.
December 2011 - February 2012 Probabilistic Precipitation Outlook. Courtesy NOAA/Climate prediction Center.
Below are graphics that represent the relative risk for enhanced cold and wet events during a La Niña winter season. Click here for details on how to interpret these graphics.
The above image represents the relative risk for extreme cold events during La Niña winter seasons across the United States. Note the northern plains has up to twice the risk for extreme cold events during La Nina winters than during ENSO neutral winters. Graphic courtesy of the Earth Sciences Research Lab.
The above image represents the relative risk for extreme wet events during La Niña winter seasons across the United States. Note the northern plains has up to twice the risk for extreme wet events during La Nina winters than during ENSO neutral winters. Graphic courtesy of the Earth Sciences Research Lab.
For more information please contact the National Weather Service in Grand Forks at 701-795-5198 or contact Mark Ewens Climate Services Focal Point 701-772-0720 x327.