Major Severe Weather Outbreak Midwest/Great Lakes; Big Snow for Colorado Mountains

Source: Storm Prediction Center

Rare November High Risk Severe Weather Outbreak

A major severe outbreak is underway for the Great Lakes Region, with a High risk issued by the SPC for parts of Illinois, Indiana, Michigan, and Ohio.  Typically, only 2-3 high risks are issued in the U.S. each year, and to get one in November is an extremely rare occurrence, especially this far north.  Currently, a large tornado has been reported on the ground in northern Illinois, to the southwest of Chicago (see radar image of the couplet below).  Additionally, PDS Tornado Watches (PDS stands for "particular dangerous situation) are in effect for much of Illinois and Indiana, as well as the southern half of Michigan.  It's going to be a dangerous day for a populated region that is unaccustomed to severe weather at this time of year.  In addition, NFL games this afternoon in Chicago and Cincinnati and 70,000+ fans at each could be affected.

Large tornado on the ground in Illinois, to the northeast of Peoria and southwest of Chicago.  Notice the couplet near Dana where the tornado is located.  Source: Radarscope

Source: Storm Prediction Center

Source: Storm Prediction Center

Early season storm brings heavy snow to the Colorado High Country

Heavy snow falls near the Eisenhower Tunnel on I-70 near Loveland Ski Area Saturday afternoon

A strong storm system in the Rockies has brought good snow to nearly all of Colorado's mountain ranges this weekend.  The San Juan Range, Elk Range (Aspen/Crested Butte), and Park Range (Steamboat) appear to be the biggest winners, with SNOTEL locations in these areas reporting as much as 1.5 - 2" of snow water equivalent.  The SNOTEL site has actually been down since 1:30 am, so more has likely fallen since then.

The new snow is great news for the mountains, which are generally near to above average for snowpack at this time of year, and much better off compared to the past two seasons, which started off exceptionally dry.  The early season snow is also providing a good starting base for ski areas that have recently opened or will be opening soon.  48-hour ski area snow reports include:  16" Crested Butte, 16" Aspen Mountain, 15" Winter Park, 15" Wolf Creek, 15" Breckenridge, 13" Copper Mountain, 11" Keystone.

The image below shows the 48-hour changes in snow water equivalent as of 1:35 this morning (more has likely accumulated in the northern mountains since then, but the site has been down).

Source: Andrew Slater, NSIDC

Welcome to MSU Denver Meteorology Blog

We've decided to start a weather blog for the Student Chapter of the American Meteorological Society at MSU Denver, focusing on Front Range/Colorado weather, interesting weather across the country, student activities, and more.  Thanks for reading!

It has been a chilly week across Colorado, as an upper level low pressure system has slowly worked its way over the area.  Most of the precipitation this week has remained west of the Continental Divide, but shallow upslope flow led to significant cloud cover and below average temperatures for the first half of the week.

The upper trough has now moved east of Denver, and the sun returned, but gusty northwest winds have resulted in another chilly day.  While we have remained dry, the mountains along and north of I-70 have been getting snow today under northwest flow, which typically produces good orographic (i.e. terrain-enhanced) snowfall for ski areas such as Vail, Winter Park, and Steamboat.  While it is still early, the snowpack is off to a strong start in the mountains, which is great news for ski areas which will be opening over the next few weeks.

700 mb Winds and Relative Humidity Map showing good snowfall-producing moisture across the Northern Colorado mountains.  700 mb is roughly equivalent to 10,000 ft. of altitude.  Source: College of DuPage

Meanwhile, the aforementioned low pressure system is working its way across the Central U.S. and is producing some severe weather this evening, with tornado watches in effect for parts of Missouri, Indiana, Illinois, and Kentucky.  Fall is actually considered a "secondary" severe weather season, so it's not unusual for the central and southern U.S. to experience severe thunderstorms and tornadoes as these mid-latitude cyclones move across the country and tap into low level Gulf moisture.  Just two years ago, Oklahoma experienced an EF-4 tornado on November 7.

Source: Storm Prediction Center