Record breaking mid-December warmth reached Chicago Wednesday.
With a high of 65 degrees, Wednesday’s temps exceeded the 50-year-old record high of 64-deg today set back in 1971. And, for a few hours just past midnight early Thursday, low 60s could set a second record high temps for Dec. 16, breaking the old record for the date of 60-deg set in 1981.
The high winds uprooted several trees on Argyle Street in Andersonville. Several cars were damaged as a massive tree came crashing down near Argyle and Glenwood.
Very Strong Winds On The Way
Later Wednesday, powerful non-thunderstorm winds capable of damage are to sweep into the area.
It’s not often you see meteorological modeling kicking out forecasts of the type of wind we have on the way tonight. Gusts topping 50–and potentially even 60 mph–are on the way to the Chicago area and a wide swath of the central and upper Midwest.
The strongest winds are likely to reach the city between 8 p.m. CST Wednesday night and 9 a.m. CST Thursday morning.
Be forewarned, the winds are to hit with particular force Wednesday into early Thursday and may send unsecured outdoor objects like porch furniture, trash cans, trampolines (there always seem to be some of those blown through the air in situations like the one developing) and other paraphernalia through the air. So it would be prudent to check and get these items inside and out of the wind ahead of time.
A High Wind Warning kicks in from I-80 north at 9 p.m. Wednesday through 9 a.m. CST Thursday —not that winds won’t blast areas south of I-80 or that winds won’t continue to blow with gusto the remainder of Thursday. They will! They’ll just miss levels required for a formal high wind warning declaration. Instead, areas south are under A Wind Advisory in the 6 p.m. to 9 a.m. CST time frame Wednesday into Thursday morning. Winds will continue to blow strongly Thursday–just not as strongly as early in the day. Velocities will drop off precipitously Thursday night.
Full forecast details and more at the WGN Weather Center blog
So what’s happening to produce such strong winds?
The powerful surface southwest winds beneath the southern flank of an intense winter storm–a system with an ear-popping (figuratively) central barometric pressure of 982 mb (29.00″) and predicted to deepen to 977 mb (28.85″) by midnight CST Wed night, sit beneath the nose of a jet stream level wind max with winds of nearly 150 mph. This is a potent high wind set-up! The front-right exit region of a jet stream wind max is a region in which air is encouraged to sink through the atmosphere–and this encourages powerful upper levels winds to “mix down” to the surface. We’ll see the effect of this atmospheric set-up Wed night into Thursday morning as wind increase here.
Some Areas of Midwest Face Severe Weather Threat
A cold front racing into humid air in the western Midwest will set up a fast-moving squall line capable of tornado and damaging wind production later today into tonight. What’s left of that squall line is to arrive in Chicago in highly weakened form late Wednesday –likely in the 11 p.m. CST to 2 a.m. time frame. It’s possible thunder might accompany a few of the remnant showers–but the bit story will be the high winds and plunging temps to follow the passage of the cold front along which these showers are predicted.