Fwd: mid-week storm potential

---------- Forwarded message ----------
From: Philip C. Ordway <pcordway@gmail.com>
Date: Mon, Feb 22, 2016 at 2:06 PM
Subject: mid-week storm potential
To: "go@blogger.com" <go@blogger.com>, chicagosevereweather@googlegroups.com

I hope everyone enjoyed the spectacular weather on Friday and Saturday. Most places hit 60F on both days, even if the winds on Friday were intense. (Those were some of the strongest non-thunderstorm winds I've ever experienced. Officially the gusts were over 60 mph with a few outliers over 70 mph.)

Now we're back into a more seasonal pattern. Wednesday into Wednesday night a strong storm will be climbing through the Ohio River Valley with the potential for heavy snow and high winds on the backside. For now, the best track appears to be far enough to Chicago's SE to prevent most of the snow from coming in here. Some big caveats: this storm looks powerful; it is likely to produce a narrow band of intense snow; and the difference between heavy snow and very little snow is only ~25 miles. A lot can change from this point forward, and even if this track verifies ares in and near Chicago could see an inch or two of snow (especially in locations downwind of a NE wind off of Lake Michigan). Anyone traveling east should have on eye on this -- Michigan could get buried, and further east it will be a windy and wet mess. 

Beyond this storm there isn't much on the horizon. The overall pattern looks seasonal, with lots of highs in the 30s and 40s. A brief shot of cold air is possible in the 7-10 day range but that's about it. 

Forecast

(This is mostly a test to make sure the problem from Saturday has been resolved.)

Snow totals yesterday were generally in the 2-3" range. Temps will hover in the 20s and 30s this week before a big warm up on Friday. Mid-50s look like a good bet. Depending on how much snow cover is around it is possible that some spots will break 60 on Friday (although it does look rainy).

Today's cold will moderate going into a period of overrunning snow tomorrow. The snow should reach most areas tomorrow morning after dawn. Areas to the west may see 3-5" of snow with areas to the east (in the city and along the lake) may only see an inch or two.

Beyond the snow temps will continue to moderate. By Friday we may be looking at 50F. And there are no additional cold air outbreaks in the horizon in February.

And speaking of 50 degrees it would be right on time. We're 10 days from the average date of our first 50 degree temp, 23 days to 60, and 38 days to 70.

We'd already added an hour and a half of daylight (the next sunset after 5:00 will be in November) and at this higher sun angle the sunny days will start to feel much warmer. The spring equinox is just over a month away.

Mild then stormy then cold

Today and tomorrow are going to be mild. Temps will be 15-20 degrees above normal, peaking in the 40s or low 50s. Tomorrow will be wet with passing showers most of the day.

Monday temps will retreat but remain above normal as a storm approaches from the west. From this distance we know that a powerhouse storm is likely in the region but details are pending. It looks like areas to our west and north could be in line for a major winter storm Monday night into Tuesday but it wouldn't take much to alter that outlook as we get closer.

Temps behind the storm look below normal. The mid-range models are keeping cold air in here through Valentine's Day.

light snow + brief thaw + possible storm + possible cold

Light snow is spreading across the area. Accumulations will be very light (maybe an inch before sunset, at most a couple of inches by midnight) but given that temps are very cold and it will be snowing during rush hour it would be wise to expect some travel disruptions. 

Beginning Wednesday into Thursday temps will moderate, likely breaking freezing and approaching 40F. Rain moves in Friday into Saturday in what looks like a potent storm -- the key question will be the temperature profile. It looks like rain for now but a switch to snow is possible. 

In the mid-range forecast there is a chance of another shot of cold air next week. This is very tentative,but this model has been good and it would fit with the storm preceding it. Stay tuned on both. 

snow then cold

We're under a Winter Weather Advisory for some snow this afternoon into the overnight hours. The heaviest snow will be in a narrow band to our SE -- there was some uncertainty overnight as to the exact track but it does look like we're only going to get sideswiped in Chicago. The most likely situation is an inch or two this afternoon/evening and another inch or two overnight for areas from the southern suburbs into the city. Amounts will be light to the north and west, so the north side of the city, northern burbs and far western burbs may only see an inch or less total. Some lake enhancement is possible along the lake (especially SE Chicago toward the IN border) so 4-6" is possible there. 

The snow this afternoon and tonight will be heavy and wet due to temps in the low 30s. It could also fall heavily at times, dropping visibility to low levels. Roads and airports will be affected. 

The snow should end by daybreak Sunday. It will be windy though, and temps will drop through the day. Another shot of snow arrives Monday -- it will be light but potentially disruptive to the evening commute. 

Behind that will be some cold air. It will be nothing like recent winters' cold outbreaks but it will still be much colder than anything we've had yet this season. Highs will be in the teens Sun-Wed, but beyond that the pattern moderates. There are no extended cold-air invasions on the immediate horizon beyond midweek. 

Warning extended to 3pm

Our Winter Storm Warning has been extended to 3:00. So far the precip has tended to the heavy and frozen side, with many if not all locations reporting sleet, freezing rain or a mix. Accumulations are minor but meaningful, with many streets (even busy expressways) covered in a layer of ice/slush. Traffic is slow but volumes are light.

Thankfully the precip will trend toward all rain by late afternoon, with temps rising several degrees. But winds will pick up and that could result in power outages in places with ice accumulations.