Chicago Severe Weather Updates: January 2019

Saturday, January 26, 2019

test

This email is confidential and intended only for the recipient(s). If you have received this message in error, please notify the sender at compliance@anabaticllc.com and delete this message and any attachments. This message is provided for informational purposes only and should not be construed as a solicitation or offer to buy any financial instruments. Please see the full disclaimer at www.anabaticllc.com.

Friday, January 25, 2019

Problematic snow today (?) followed by big snow Monday and then extreme cold

We recorded a -8F (preliminarily) at ORD this morning. That is the first subzero low of the season and the first since Feb. 5, 2018. We are not likely to record the rare feat of a subzero high temp today, but we may get one next week (see below).

Don’t let the beautiful, cloudless sunrise fool you – we could get ½ to maybe 1-2 inches of snow this afternoon and evening. This didn’t look like much, but it now seems that there will be just enough “lift” and just enough moisture to get some accumulating snow starting in the 3-5pm range. Areas north of the Eisenhower *could* miss out on the snow, and the snow *could* start after the commuting peak, but I wouldn’t plan on either if you need to be somewhere in a timely fashion tonight. The snow will be light and fluffy given the extreme cold, but the other result of the cold is that salt is only marginally effective – any snow that does fall will stick on the roads. We all know that even a light snow during peak commuting times can create gridlock on the roads, so be advised.

Big snow on Monday? I will send an update on Sunday morning, but for now I would plan on a significant and disruptive snow on Monday. The early (low-confidence) over/under is six inches, starting late Sunday and going most of the day on Monday. Leading into the snow on Sunday night and Monday temps will be cold (single-digits up to the low 20s) and that won’t help the road conditions on Monday.

Extreme cold Tuesday-Thursday? We are looking at potentially historic cold next week. Details are tough at this distance, but there has been remarkable agreement for days on a major inflow of polar air beginning Tuesday. Model temperatures at altitude from the Dakotas, Minnesota, Nebraska, Iowa, Missouri, Wisconsin, Illinois, Michigan, Indiana and Ohio are showing levels seen once or twice in the ~40 years we’ve had satellite data.

Wednesday is shaping up to be the coldest day since 1996. A decent guess right now would be a low around -16F and a high around -4F. If so, -16F would break the record low for Jan. 30^th (set in 1966 at MDW).***

As noted in my last email, a temp below -15F is very, very rare in Chicago (~one per 1,850 days, or ~two per decade).
If we do get a subzero high next week, it would be extremely rare. There are only 64 days on record* that failed to break 0F – that’s once every 2-3 years. We haven’t had many in recent years – just three in the past 25 years (-2F on Jan. 6, 2014, -1F on Jan. 15, 2009, and -5F on Feb. 3, 1996). The all-time record-low high temp was -11F on Christmas Eve 1983.

Here is your evergreen reminder that we do not speak of wind chill values around here. You have different skin, hair, body fat, and clothes than your uncle Jerry and your Meemaw and everyone else, and even if you don’t, it’s still a bad idea to assign numbers based on a pseudo-scientific “formula” that was completely overhauled in 2001 and is still not based on anything resembling science but is somehow afforded credibility when generating numbers that are conflated with actual temperatures (the physical quantity that expresses hot and cold by measuring thermal vibration at the molecular level) and generally bastardizing meteorology in every possible way. Wind chill is to science as that last sentence is to good writing.

*** Here is your periodic reminder that Chicago’s official temperature records date to 1872 but have been recorded in four very different locations: the Loop, Hyde Park, Midway, and (since 1980) O’Hare. Compare with care.

http://blogspot.us10.list-manage.com/subscribe?u=4f8accdd34bc929d771695a53&id=c99247d27b

Chicago Severe Weather Updates

blogspot.us10.list-manage.com

Chicago Severe Weather Updates Email Forms

Wednesday, January 23, 2019

cold, then snow, then extreme cold

Well, after winter came early in November and then disappeared for all of December and the first half of January, we’re packing it all in to these three weeks…

A blast of cold air will arrive tomorrow, and by Friday we’ll be in the deep freeze. Friday morning should see our first official subzero temps of the season (long-term average is five per year, with 3-4 already on the books by now). Saturday will also be cold before Sunday moderates toward seasonal norms.

Late Sunday night into Monday could feature a significant snow. A classic-looking set-up is coming together and could bring several inches overnight Sunday through the day on Monday. Stay tuned – it’s way too early for details, but be on the lookout if snow on Monday morning would be a problem for travel plans, etc.

Following that potential snow on Monday, cold air looks likely to spill into the eastern third of North America. The graphic below shows a blob of frigid blue – the air that would normally be parked right above the North Pole – sitting on the Great Lakes. Some models are putting out numbers that are also cold as anything we’ve seen in decades, and numbers that have only been recorded a handful of times in 30-40 years. Again, it’s way too early to feel confident in any details. Just be prepared for the potential to see double-digit subzero temps on Wednesday (Jan. 30^th). One credible model is looking at -15F to -20F that morning. The second graphic shows the actual set-up on Jan. 6, 2014 – the original outbreak of the godforsaken term “polar vortex” – when Chicago recorded an official (and record-breaking) low of -16F. You don’t need a PhD in meteorology to see the similarities, but again, consider the pattern and odds, not the details, for now. For more context on how rare that would be:

Chicago has only recorded 29 days of -16F to -20F – that’s 0.0005%, or roughly one out of 1,852 days, or about two days per decade. *

There have only been 11 days of -21F or colder – that’s 0.0002%, or roughly one out of 4,762 days, or about two days every 25 years.**

The daily record for Jan. 30^th is -15F (taken at MDW).***
The ONLY January temperature record we’ve broken since 1985 was the -16F on Jan. 6, 2014.

Other fun facts: since the brutal cold of some winters in the 1980s we have only set five daily cold records, and only one this decade:

-16F on Jan. 6, 2014
+4F on Dec. 5, 2005 (that one is begging to be broken!!!)
-8F on Dec. 12, 2000
-16F on Feb. 2, 1996
-19F on Feb. 3, 1996

If the daily average temp of ~8F verifies for Jan. 24-30^th it would rank as the coldest such period recorded at O’Hare since 1980

* Here is your periodic reminder that we do not speak of wind chill values around here. If you want the full rant just email me and I’d be glad to oblige.

** Chicago’s all-time record low was -27F at ORD on Jan. 20, 1985. Please don’t let people tell you otherwise, or conflate Satan’s plaything – also known as the wind chill – with actual temperatures.

*** Here is your other period reminder that Chicago’s official temperature records date to 1872 but have been recorded in four very different locations: the Loop, Hyde Park, Midway, and (since 1980) O’Hare. Compare with care.

http://blogspot.us10.list-manage.com/subscribe?u=4f8accdd34bc929d771695a53&id=c99247d27b

Chicago Severe Weather Updates

blogspot.us10.list-manage.com

Chicago Severe Weather Updates Email Forms

Tuesday, January 22, 2019

WWA -- freezing rain; temp rollercoaster

Sorry, just a quick heads-up for travel problems since we’re already having heavier-than-expected ice accumulations this morning. The very cold temps at ground level are causing some immediate glazing. Warmer air is flooding northward on the backside of a strong storm (central Iowa to Milwaukee and points north are getting hammered). Rain at altitude is falling into cold air at the surface and freezing on contact. There are already a bunch of accidents on the roads, and even some untreated sidewalks are going to be slippery by this afternoon.

Freezing rain and sleet through sunset. A period of rain possible far south burbs.
Rain could shift north tonight as temps continue to moderate.
Precip should shift back to all snow by tomorrow morning. Totals should be <1”.

Again, roads are becoming an issue, and O’Hare is already backing up under a ground delay program.

A sunnier, dry and seasonable day on Thursday gives way to an Arctic blast on Friday (highs <10F, with our first <0 lows of the season possible on Friday and Saturday morning). Temps will be cold but closer to seasonal norms as Saturday and Sunday add ~10 degrees each.

Another storm worth watching will traverse the country early next week. If things play out as they look now, that storm could pull down the coldest air of the season a week from now. In fact, some models are putting out crazy numbers – one of those lobes of polar air dislodged a few weeks ago could be parked right over the middle of the country, and if so we could see temperatures that have only happened a few times in 30-40 years.

The broader picture of the next 7-14 days is similar to what we’ve just had. Periodic storms are riding across North America as these lobes of frigid air collide with milder air to the south. 1-2 days of frigid temps are then replaced by more seasonable (but still cold) air. The overall pattern thus averages out to well below normal, and for now there is no sign of a flip back to the extremely pattern of December and early January.

http://blogspot.us10.list-manage.com/subscribe?u=4f8accdd34bc929d771695a53&id=c99247d27b

Chicago Severe Weather Updates

blogspot.us10.list-manage.com

Chicago Severe Weather Updates Email Forms

WWA -- freezing rain, then temp rollercoaster

Freezing rain and sleet through sunset. A period of rain possible far south burbs.
Rain could shift north tonight as temps continue to moderate.
Precip should shift back to all snow by tomorrow morning. Totals should be <1”.

Again, roads are becoming an issue, and O’Hare is already backing up under a ground delay program.

Friday, January 18, 2019

Winter Storm Warning

The official upgrade just went through, and we’ll be under a Winter Storm Warning from 3:00 this afternoon until noon tomorrow.

Snow will begin between 3:00 and 6:00 today for most locations.
- Again, the evening commute could be slooooow if the snow has started by then. It doesn’t take much to turn a Friday evening commute into a slog.
- Hopefully road crews can catch up overnight and stay on top of it during the day on Saturday, but there will be plenty of areas will snow-covered and slippery roads.
- The airports are going to be in trouble from ~6:00 tonight through noon tomorrow. This is a massive storm that is affecting almost the entire country east of the Rockies, so the ripple effects are enormous. Travel waivers are already being offered by most airlines. (see below for the list of all 24 cities Southwest is covering right now!)
The snowfall could be heavy at times tonight, and the peak snowfall rates will come with winds gusting 30-40 mph overnight.
Snow will continue through most of the morning on Saturday before tapering. Low-coverage but high-intensity bands of lake-effect snow will come through on Saturday afternoon and evening. Isolated spots could see another 1-4+ inches just from the lake-effect.
Storms totals through Saturday night are probably an inch or two than they looked yesterday, but lake-prone areas could see even more as the wind set-up is increasingly favorable for lake snow. (Also remember that most of this snow will be overnight, but almost half of it could pile up after sunrise on Saturday.)
- 3-8 inches is a good guess for most of the area.
- 6-9+ inches is likely in areas that see lake-effect. Right now, NWS is favoring an area near the lake in northern Cook and southern Lake for the most lake-effect snow, with totals approaching a foot there. Again, this is really hard to pinpoint, and it wouldn’t surprise me if that area shifted or if totals ended up several inches outside that range. It wouldn’t take much for those lake-effect bands to slide south and put white-out conditions into the Loop.
- The odds of a bust (<2”) and a boom (>12”) are each about 10% for any given location in Lake, Cook, or Dupage.

Winter Storm Harper

Based on the forecasted weather conditions, our scheduled service to the cities listed below may be disrupted (flights may be delayed, diverted, and/or cancelled) on the following dates:

Thursday, January 17, through Friday, January 18

· Des Moines (DSM)

· Omaha (OMA)

· Wichita (ICT)

Friday, January 18, through Saturday, January 19

· Cincinnati (CVG)

· Cleveland (CLE)

· Columbus (CMH)

· Indianapolis (IND)

· Kansas City (MCI)

· St. Louis (STL)

Friday, January 18, through Monday, January 21

· Albany (ALB)

· Boston (BOS)

· Buffalo (BUF)

· Chicago (MDW)

· Hartford (BDL)

· Long Island MacArthur (ISP)

· Manchester (MHT)

· Milwaukee (MKE)

· Newark (EWR)

· New York LaGuardia (LGA)

· Philadelphia (PHL)

· Pittsburgh (PIT)

· Portland, Maine (PWM)

· Providence (PVD)

· Rochester (ROC)

http://blogspot.us10.list-manage.com/subscribe?u=4f8accdd34bc929d771695a53&id=c99247d27b

Chicago Severe Weather Updates

blogspot.us10.list-manage.com

Chicago Severe Weather Updates Email Forms

Thursday, January 17, 2019

Winter Storm Watch

NWS has already issued a Winter Storm Watch for the entire area beginning tomorrow (Friday) at 3:00 pm CST and running through noon on Saturday. Heavy snow with 4-8” and locally heavier totals. Blowing snow may also be an issue on Saturday.

For the Chicago area:

Snow begins tomorrow afternoon. The heaviest snowfall rates will be overnight. Lake-effect snow is a major wildcard, especially on Saturday.
- The evening commute could be tricky. It might not be piling up too much by then, but even an inch of sticking snow on a Friday evening commute can make for looooooooong delays on the roads. The airports will see some delays and cancellations too.
Snow totals through Saturday night should be in the 3-6 inch range. Totals of 6-8+ would not be a surprise. The chance of a bust (<1-2”) is low – less than 10%. But the chance of a boom (>8”) is moderate – about 30%.
- A little bit – or lack – of lake-effect snow can make a big difference. Getting a precise read on that in advance is impossible

I’ll send an update tomorrow morning as the guidance is refined, but as this point I would expect an upgrade to a Winter Storm Warning and relatively little change in the overall picture.

Other notes:

Lake-effect snow is an issue given the strong NE wind and warm water. Lake-prone areas are in play for bursts of very heavy snow and totals that exceed the average across the area.
Air travel disruptions are going to be hard to avoid. The entire eastern half of the continental U.S. is going to be fighting rough weather for the next 1-3 days.
- Snow/ice from Dallas to Philly, NYC and Boston
- Heavy rain and thunderstorms everywhere else: Houston to Atlanta to Florida to the Carolinas
Roads are going to be tough on Friday until the PM commute clears and the plows can catch up. Some roads will be snow-covered on Saturday, and heavy bands of lake-effect will make for sporadic white-out conditions, but overall road conditions should be fine by Saturday afternoon.
A corridor from central Illinois through Indianapolis and northern Indiana to Cleveland and Pittsburgh and upstate NY, is a good bet to see more than a half-foot of snow. Northern PA and upstate NY are a good bet to see more than a foot of snow.
Cold weather is locked in for the next two weeks. We’ll have at least a few rounds of snow, punctuated with cold outbreaks.
- I don’t see any reason to put stock in long-range models because unlike the 1-/7-/10-day models they’re just not very good. But given that the arctic has returned to “normal” and this is “triple split” of the PV, you’d think we would have more episodic cold/snow than in prior years with a similar cold/snowy pattern. Also, winter in eastern North America had a very mild start, and it’s already more than halfway over. It wouldn’t surprise me if there is another big flip back toward mild weather by early-/mid-February.

Local odds of >4 inches are >70%:

Regional odds of >8 inches:

For my two polar-vortex enthusiasts:

A great video of a model depiction of the polar vortex split a few weeks ago: https://twitter.com/twitter/statuses/1084935021171924992
Also shown here from above:

Tuesday, January 15, 2019

Significant snow potential -- halfway through winter, winter arrives

Well, the cold then mild pattern we’ve had this winter is turning cold again.

It is very early, but a significant storm is taking shape for Friday and Saturday. The models below are a good guess, but specifics on track and snow totals are impossible to pinpoint this far in advance. I would put high odds on at least a few inches of snow and disruptions to travel I the shaded areas from Friday night through Saturday. It looks like some locations in the Midwest and Northeast are going to be hit by a foot or more in a major winter storm, but again the details are far from set. Stayed tuned for an updated on Thursday as things come into focus.

For those of you – and I do mean both of you – interested in the inside baseball of this situation, here goes:

A couple of weeks ago the upper atmosphere above the arctic underwent a massive warming. The pros call it a “sudden stratospheric warming.” Temperatures at altitude went from about -100F to above zero in a short period of time. That is…not normal. And it pushes all that cold air down toward the ground and south, away from the north pole.
The poorly-named (and often-misused term) polar vortex is really just a near-constant area of low pressure above the arctic that keeps the coldest air contained within an atmospheric river. When this sudden warming happens that “river” gets distorted and disrupted by the movement of the cold air.
Chunks of that bitter air start floating across the planet toward places that normally wouldn’t be so cold. This time, there are three distinct “lobes” of cold air – think of them as icebergs floating in a current. The biggest one has been hammering Europe for about a week. A smaller one is about to descend on Canada, the U.S. Midwest and the U.S. Northeast.
The arctic has already recovered to “normal” – i.e., the river of air containing the coldest air above the polar cap has reformed. But we still have to wait for those “icebergs” to float along and dissipate, which will take another 7-10 days, roughly.
It does not, for now, look like this will persist into February, but stay tuned on that.

Also, for football fans and/or degenerate gamblers, the over/under for kickoff temp in Kansas City on Sunday is about 4.5 degrees F. It could well be below zero at some point during the game, among the coldest NFL games ever played.

Thursday, January 10, 2019

Snow!

It’s going to snow!!!!! Red alert!!!!

Ok, not really. We might get an inch or two Friday night into Saturday. This definitely doesn’t qualify as severe/disruptive, but I’m super bored with the weather around here lately so I had to send something.

The details for this storm are not impressive. A legit winter storm will affect the St. Louis area, but it will peter out and stay well south of Chicago before regathering some strength along the East Coast.

Still, we could have some slow roads and minor air travel delays late Friday night into Saturday.

Downstate and areas well south I-80 could get 3+ inches.
Most of Cook/Dupage will see 1-2 inches, if that.
Parts of the city and northern suburbs might see a light accumulation or nothing at all.

And yes, this winter has been exceptionally quiet. After a crazy November – the post-Thanksgiving storm was among the top three craziest winter storms I’ve ever experienced here – and a week or two of legit cold, everything went very mild and very quiet. This is right up there among the “warmest” and least-snowy six-week winter periods on record.

Yesterday marked the first below-normal temperature day in a month, breaking a string that began on December 11^th.
The snow drought has been pretty incredible. At just 1.6” this is the fourth-least snow we’ve ever had from Dec. 1 to Jan. 9.
- November was so crazy – 12.7” officially, including the fifth-highest single storm snowfall total ever recorded in November – that we’re still running ahead of the normal season-to-date pace despite receiving so little in December and January.
- I don’t know if November has ever been the snowiest month of a winter season, but 12.7” is above average for any month so we have a chance of doing it this year. I doubt that has ever happened and I’ll try to find out.
There is no significant, sustained cold weather or any major storms on the 10-day horizon

As a side note, time flies.

We’re a month past the earliest sunset, 2 ½ weeks past the solstice, and almost a week past the latest sunrise.
We’re adding well over a minute of daylight per day, and two weeks from now we’ll be adding more than two minutes per day.
The coldest week, on average, is next week.
We’re almost at the halfway mark for accumulating snowfall. (Snow is also back-weighted in the season, and once we get to late February and March the snow that does fall tends to melt pretty quickly unlike the snow that falls in December/January and lasts for weeks.)

Pages

Saturday, January 26, 2019

Friday, January 25, 2019

Wednesday, January 23, 2019

Tuesday, January 22, 2019

Friday, January 18, 2019

Winter Storm Harper

Thursday, January 17, 2019

Tuesday, January 15, 2019

Thursday, January 10, 2019