The winter of 2010 - 2011 officially over, but winter-like weather continues

It's March 1, and meteorological winter--the 3-month December, January, February period--is officially over. However, below-average temperatures and winter-like conditions will continue to affect most of the U.S. through the middle of March, and the groundhog definitely messed up his end-of-winter forecast when he failed to see his shadow on February 2 and predicted an early end to winter. While the latest computer forecast models are not showing any new Nor'easters will affect coastal New England in the coming ten days, Chicago and Detroit may see a major winter storm on Saturday, and additional significant snows are likely next week over the Upper Midwest. The potential for additional heavy snows over the Upper Midwest next week is a major concern for North Dakota, South Dakota, Minnesota, and Wisconsin, where winter snows 200% - 400% of average have piled up a snowpack that is among the wettest on record. December-January precipitation ranked in the top ten over the past 116 years. If you take all the snow that is piled up an melt it all at once, it would amount to more than six inches of rain over large swaths of the region. The NWS is predicting a 10 - 30% chance that Fargo, Grand Forks, St. Paul, and portions of South Dakota will see their highest floods in history this spring when that massive snowpack melts.


Figure 1. The amount of water locked in the current snowpack if one were to melt all the snow on the ground. Snow depths in excess of 18 inches with a very high water content lie across much of the Upper Midwest. Image credit: NOAA/NOHRSC.

Severe weather, floods hit Midwest, Southeast
Severe weather swept through the Midwest and Southeast yesterday, with six reports of tornadoes in Tennessee, South Carolina, and North Carolina. One tornado-related death was reported in Franklin County, Tennessee. NOAA's Storm Prediction Center logged 154 reports of high winds, and 24 reports of large hail. Heavy rains of 2 - 3 inches fell over a large swath of Indiana and Ohio, leading to moderate to major river flooding.


Figure 2. Severe weather reports logged by NOAA's Storm Prediction Center on February 28, 2011.

I'll have a new post on Wednesday.

Jeff Masters