What a difference a week makes.
Just last week winter blasted the big chunks of the USA with ice and snow. Today it looks and feels like springtime in much of the nation.
A surge of mild air has rapidly melted much of the snow cover in the nation. Three days ago 63% of the USA was covered by snow. Today that number has melted away to just 32%. Roughly half of the USA surface area covered by snow has melted in just the last 3 days!
NOHRSC snow depth on Friday February 11th shows 63.1% of the USA covered by snow. (click images to enlarge)
USA snow cover dropped dramatically to just 32% of the USA Monday.
Check out this amazing animation of snow cover growing and then rapidly melting on the USA in the past two weeks. (Hint: Set the animation rate at around 30 for a quicker loop)
70s in Nebraska!
The Chinook fueled warmth caused high temperatures to surge into the 70s as far north as western Nebraska Sunday.
Sunday’s high temps. (Click to enlarge)
“Snow free zone” approaches Minnesota:
The weekend warmth pretty much destroyed snow cover as far north as a Pierre, SD to Omaha line. There are big holes now in the snow cover in Iowa, and as little as 2″ on the ground in north central Iowa not far from the Minnesota border. There may be some snow free bare ground in parts of Minnesota this week!
There’s still plenty of snow in northeast Minnesota and along the Minnesota River Valley in southwest MN and in the eastern Dakotas. It will be interesting to see where we are at week’s end with more 40s in the forecast. It will also be interesting to see if river stream gauges begin to spike this week as runoff is released into watersheds.
All quiet for now on the Red River at Fargo.
Do “Atmospheric Rivers” trigger massive floods & snowstorms?
We’re learning about new features in the atmosphere all the time. Just as medical imaging is giving new insights inside the human body, remote sensing is giving meteorologists a better understanding of previously unseen features in the atmosphere.
“Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.”
Check out the full NOAA release on “atmospheric rivers” here.
National Severe Storms Lab gets new Director:
There’s a new Sherriff at NOAA’s NSSL.
“Steven Koch spent time in Norman, Okla., while he earned his doctorate in meteorology in 1979. He’ll return to Norman in late April as the new director of NOAA’s National Severe Storms Laboratory, the laboratory most involved with tornado research.”
Warmth returns Tuesday:
You’ll notice the wind will be a little milder Tuesday through Thursday as the next surge of milder air pushes in from the south. Temperatures may spike into the 40s again, as we continue to melt snow in “The Great Snow Eater of 2011.”
Look for a sharp cold front to drop temps back to seasonal levels (20s) Friday & Saturday. There may be some light snow with the front Friday…and perhaps a better chance of accumulating snow by next Monday.