Chicago Severe Weather Updates: March 2017

Monday, March 13, 2017

Lake-Effect Snow Warning

Sorry, one last update. After >1-2” snow totals from the passing system we’ve been upgraded to a Lake-Effect Snow Warning tonight at 7pm through tomorrow afternoon for Cook, Lake and DuPage. The storm that has just passed us is really intensifying (see below) and that is going to pull cold air across the open water of Lake Michigan and right into Chicago. Favored locations in Lake and northern Cook could easily 6-8” or more of additional, and most of the area will see at least another inch or two.

And our storm is going to explode on the East Coast. It’s not quite “March 1993 Superstorm” level but it’s still very impressive. The entire NJ/NY/CT/New York City area is under a Blizzard Warning – winds could easily hit 60-70 mph in Manhattan with over a foot of snow. DC might get “missed” with 3-6” of slushy mix, but things escalate just to the north and west with a band of 10-inch to two-foot snow totals likely throughout the NE corridor and New England. Even if any of several factors cut the snow totals slightly the incredible strong winds are a lock and will leave quite an impression.

American Airlines just cancelled every single flight to/from LGA and JFK for the entire day tomorrow, and other airlines will likely do the same. All travel from DC to Philly to NYC to Boston is going to be a joke tomorrow, and it may take a day or two to recover.

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Sunday, March 12, 2017

last snow update

Not much change to the overall picture. Snow has started to fly in the far N and W suburbs and will overspread the area in the next hour or two. Most locations will see 1-3” by morning and another 1-4” during the day tomorrow. Favored lake-enhanced areas may see totals creep above 6-8” by Tuesday morning. One note about the snow totals, though – it’s going to be a pretty wet snow and temps will be in the low 30s so snow should compact and melt pretty quickly. Snowfall rates will also be light/moderate and roads that are (pre)treated should be wet, but I would still expect some travel delays tomorrow.

The East Coast, meanwhile, is in for a major storm. It’s impossible to get the details right, but at this point if you needed a textbook model of a powerhouse Nor’easter this would be eat. The entire DC-BWI-PHL-NYC-BOS corridor is in the bullseye for a huge snow. The entire region is under a Blizzard and/or Winter Storm Watch. The over-under on snow in NYC is trending over a foot and about 14” in Boston.

snow update -- WWA here, major disruptions (WSW/Blizzard) elsewhere

Cold temps and a potent disturbance are coming together to create a pretty strong late-winter storm. The cold has gone far enough south to create sticking snow this morning in Charlotte, NC and Augusta, GA! That is just the prelude, though -- Winter Storm Watches and Blizzard Watches are up for areas to our west and north as well as much of the Northeast Corridor. The entire Chicago area is under a Winter Weather Advisory for 3-6” of snow. At least 2” of sticking snow looks likely for the entire area, and in favored areas (far W/NW and along lake) up to 8” is possible. This is also all but assured to snap our streak of days without 1” of snow at 85 or 86 days. (I believe the all-time record is 87, which is a shame.)

This is going to be a fairly long duration snow given the size and scope of the low. Despite the beautiful sunshine this morning an overcast will develop quickly by late morning or early afternoon and snow could be flying by early evening. Moderate snow could fall off and on tonight with considerable snow tomorrow morning. As the low moves east the backside NE flow could add some lake-effect through Tuesday morning.

Travel disruptions should be expected tomorrow – roads and airports will be slow for the morning rush, if not beyond.

The meat of the storm will pass through the MSP area and the Mississippi Valley into Wisconsin before swinging east. 4-8” of snow, if not more, looks likely there. And the real problem looms on the East Coast. The track of the low, as always, is tough to pinpoint, but the best guess we have right points to a very potent storm tracking the coast in the favored location for heavy snow. Large portion of the NYC and New England population centers are under Blizzard Watches and the rest are under Winter Storm Watches. 4-6” in DC quickly trends toward a foot or more from NJ through NYC into NE/Boston. Right now the 50% probability is for a foot of snow right through the NYC-CT-Boston corridor, and one good model is leaning toward 14-16” or more. This far into March it would normally be hard to draw enough cold air into the storm, but it s 9-degrees in Boston this morning, so that problem has already been solved. Major travel disruptions are likely from Monday night through most/all of Tuesday.

Friday, March 10, 2017

Snow?

Winter isn’t quite done yet – in a special dose of irony, it looks likely that for the first time ever we will have a snowier March than the preceding January and February combined.

Other areas (see below) are going to get it worse, but starting Sunday night and lasting through some or most of the day Monday we’re likely to see a few inches of wet snow. Details are too hazy to pinpoint, but anywhere from a slushy covering to 3-4” look possible at this point. The ground is obviously very warm and hopefully the roads will be treated, but I would still expect some travel problems (especially on the Monday morning commute).

Beyond Tuesday/Wednesday the pattern will flip and we’re likely to be well above average (i.e., 50s and maybe 60s) by the following weekend.

In the meantime, our snow on Sunday/Monday could be a much bigger deal to our south and west, and once it moves east it could develop into a potent nor’easter. The track is too uncertain for the DC-NYC-Boston corridor, but it could be anything from a vicious, driving rain with 40-50 mph winds or a major snowstorm. 2-6” in DC to well over a foot in NYC/Boston are possible in the latter scenario. Travel disruption looks very likely Monday/Tuesday across the entire Northeast.

Monday, March 6, 2017

severe threat tonight

After missing last week’s storms I’m trying to make up for it, especially since there is a decent threat of a repeat late tonight. Today’s gusty winds in advance of a cold front will feed approaching storms between 10pm and 2am. We’re on the far NE corner of an area outlooked for severe weather, as depicted by one model shown below. Brief downpours and damaging winds are possible. Even if we get severe-warned, though, I’m hoping to sleep through this one.

Tomorrow should be windy but sunny and mild. Beyond that we’re likely to settle into a wet and chilly period. We’re going to sit on the southern edge of some cold air, and a couple of bouts of passing rain or snow look likely from late week through early next week. Some snow is possible, and it wouldn’t take much for March to end up snowier than January and February combined! Barring the unexpected development of a major storm, any snow would likely be limited to a few inches and be gone within a day or two. The pattern looks likely to flip to a milder one by mid-/late-month.

Wednesday, March 1, 2017

severe outbreak (apology) + record February and winter

Happy Spring 2017 to everyone.

First off, an apology. I was out of town for a few days and then yesterday I was on an airplane from early afternoon through early evening. So I knew there was some severe risk going into that time period, but we were on the very marginal northern edge of the area of concern, and there was no formal watch, and I had very little time to watch the development (with no way to monitor it) etc. etc. So I thought less would be more and I didn’t send anything around. My apologies for going AWOL during what turned out to be a significant and unfortunately tragic severe weather outbreak.

As you may know, there were several tornadoes about 50-125 miles WSW of Chicago yesterday, and at least one fatality resulted. That horrible loss of life also coincides with the only documented tornado in northern Illinois during the month of February.

And with last night’s severe storms we also closed the books on meteorological winter. Some highlights:

We set an all-time record by recording only 0.6” of snow and recording zero days of >1” of snow cover in the Jan-Feb period. It was a truly historic and almost unthinkable snow drought. (And one that looked pretty unlikely to some after the first two weeks of December opened cold and snowy. I’d also point back to the “forecast” in the Farmer’s Almanac that called for an especially cold and snowy winter in the area.)
We’ve never had more 70-degree temps in February than in any prior February.
We produced the longest string of consecutive 60-deg temps during any winter period.
We set the record for the the longest string of days in a winter season to have failed to produce a single 1" snow (12/17/16 through 2/28/17).
We officially had the 3^rd-warmest February on record (just two years after tying the coldest-ever February) and Midway had its all-time warmest February since opening in 1928.
We finished well above average in temperature and below average in snowfall for the Dec-Feb period.

And despite today’s flurries the mid-range forecast is mild. Temps will average near- to above-average for the next week or so, and the weekend looks nice (sunny with temps in the 50s to near 60).

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