Friday, November 20, 2015

6 Things To Know About Winter Storm Bella

Jon Erdman
Published: November 20,2015

Winter Storm Bella will lay down a swath of snow, heavy for some, in the Midwest and Great Lakes into the weekend.
(MORE: Forecast Details | Latest Impacts | Winter Storm Central | Science of Naming Winter Storms)
Here are six things to keep in mind about this first major Midwest winter storm of the season.

1. Not Your Typical "Season's First" Snow

Any preconceived notions of easing into the snow season should be thrown out with this winter storm.
Instead of a gentle dusting, the first measurable snow of the season for a swath from Iowa to Lower Michigan may be a 6-inch-plus dumping.
(FORECAST: Des Moines | Chicago | Milwaukee | Detroit)
In many of these locations, the first one-inch-plus snow of the season usually comes by the first week of December. So, this is not only early, but impressively heavy.
Chicago hasn't seen 6 inches of November snow since 1978, just months before a 1979 blizzard cost Mayor Michael Bilandic his job.
Similarly, Milwaukee hasn't seen 6 inches of November snow in 20 years.
So, get your snowthrower ready. A shovel may not be enough.

Snowfall Forecast

 

 

 

 

 

 

 

 

 

 

 

2. Snow Could Vary Greatly Over Small Distances

As in many snowstorms, snow totals should be highly variable over small distances, including some metro areas.
Small-scale snowbands, on the order of 5-10 miles wide, can produce heavier snowfall rates in excess of 1 inch per hour. Predicting exactly where they'll set up is exceedingly difficult, even a day before the event.
This has already occurred over the Sioux Falls, South Dakota, metro area, with light accumulation north of the city and over a foot on the city's south side.
Winds flowing off Lake Michigan, while enhancing snowfall rates by adding moisture to the air, will also warm the lowest levels of the atmosphere nearest the lakeshore, as water temperatures over southern Lake Michigan are in the upper 40s.
Thus, the northwest suburbs of Chicagoland are likely to get the heaviest snow, while areas closer to the lake will see less.

A tractor-trailer spun out into the median of Interstate 29 between Sioux Falls, South Dakota, and Sioux City, Iowa during Winter Storm Bella on Nov. 20, 2015.
(Denna Huett Boardsen/Facebook)

3. Road and Air Travel Delays

If you're getting away early for Thanksgiving week, leave extra time. Flight delays are likely out of Chicago-O'Hare particularly Saturday morning. Delays are also possible Friday in Des Moines and Saturday in Milwaukee and Detroit. Check your flight status before heading to the airport.
Road conditions will also deteriorate later Friday in Iowa, then into Saturday farther east along the snow swath into southern Wisconsin, northern Illinois, Michigan and northern Indiana.
Given this is the first snow of the season in these areas, you should assume many people will be rusty on their winter driving skills. Slow down, leave extra distance and consider postponing travel, if possible.
There may be some reduced visibilities and minor blowing and drifting snow Friday night into Saturday, particularly in rural areas.
(INTERACTIVE: Driving Forecast)

Sunday: Bella Is Done

 

 

 

 

 

 

 

 

 

 

 

 4. Bella Will Move Quickly

One factor cutting down Bella's snow total will be its fast movement.
By around midday Saturday, the snow will be finished west of the Mississippi River, as well as much of Wisconsin and Illinois, with the possible exception of lingering lake-enhanced bands near Chicago.
By late Saturday night into Sunday, the large-scale snow should have pulled into Canada, leaving only lingering lake-effect bands in its wake.
Which leads us to ...

Sunday Morning's Forecast Lows

 

 

 

 

 

 

 

 

 

 

 

 

5. Coldest Air of the Season Follows

Get ready for some mid-winter cold for a little while after Bella.
Highs Saturday may not get much above freezing from the western Great Lakes into the Upper Mississippi Valley and northern Plains. Colder yet, some locations won't get out of the 20s for highs this weekend!
With this fresh snow cover, clearing skies and lighter winds, lows Sunday morning may plummet into the single digits and teens in the Bella snow areas, with 20s plunging into the Tennessee Valley and Deep South Sunday and Monday.
If this sounds a bit depressing already, there's some good news ahead.

Thanksgiving Forecast

 

 

 

 

 

 

 

 

 

 

 

6. The Snow Will Be Gone Next Week

The thing with early (and late) season heavy snow is that it may not last.
Sure enough, the jet stream will rearrange itself Thanksgiving week, allowing cold air to lock itself in place over the West, and only slowly oozing its way south into the northern Plains.
That, in turn, will force the Gulf of Mexico to open for business, sending warmer air north into the Upper Midwest, kicking out the post-Bella cold air.
By the middle of the week, highs should recover into the 40s or 50s in most of the areas blanketed by Bella's snow.
(MORE: Thanksgiving Travel Outlook)
Unfortunately, a soaking rain is then looking probable around Thanksgiving into Black Friday in the Upper Midwest. That would turn this weekend's blanket of snow getting you in the holiday spirit into a March-like mess of puddles, mud and could lead to some local flooding.
Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Twitter and Google Plus. 

MORE: Winter Storm Linus - Feb. 2015 (Fifth Heaviest Chicago Snowstorm)

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