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January 24 - 31 Cold Blast

MNstorms

By MNstorms,
in Lakes/Ohio Valley

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beavis1729

beavis1729

Posted
Posted
14 minutes ago, Chicago Storm said:

Good news is that even the GFS with the miss north for the hybrid storm, still has lows in the -30's and highs in the -20's on Wed.

Yeah, the 12z GFS generally held serve on the arctic outbreak, although verbatim it's a bit shorter in duration than what has been shown over the past few days.  Strange outcome...because you'd think that with the Monday storm being more north, it wouldn't be able to pull the cold air down as far south as before...yet it still did.

Heck, I'll take a -12/-22 day at ORD, to set the all-time low max.  You'd think Thursday 1/31 has the best chance of doing this, as it will likely not have a midnght high going into the day...but of course it could warm up later in the evening of 1/31 if the arctic air mass begins moving out.  It makes 1/18/94 and 12/24/83 even more remarkable to think about, both with highs of -11.

At this point, it doesn't look like the all-time record low will be set.  Of course it was always a long shot due to UHI and needing a million things to go right...but it actually looked possible over the past few days. 

Still nice to see the sub-480 thicknesses on the GFS, though.    

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buckeye

buckeye

Posted
Posted
3 hours ago, Chicago Storm said:

Good news is that even the GFS with the miss north for the hybrid storm, still has lows in the -30's and highs in the -20's on Wed.

:lol:  from one weenie to another.... I get where you're coming from but most folks would think you're bat sh*t crazy for calling -30's the good news

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beavis1729

beavis1729

Posted
Posted

LOT AFD, long-term from Izzi 

Tuesday through Friday...

Record breaking and potentially historic outbreak of cold still
appears to be in the offing for the middle of next week. Greater
than normal degree of forecast uncertainty in temperatures, due in
large part to models showing all time records being broken and in
some cases shattered.

Generally made only very small tweaks to the temperatures from the
model blend, due to the uncertainty. It is worth noting, that this
model blend includes bias-corrected grids which still reflect a
bias correction warmer from the unseasonable warm spell back in
late Dec and early Jan and also contains a MOS component which
tends to have some weighting toward climo, which obviously midweek
temps will not look anything like climo. Typically, in record
breaking temperature situations, a blend of the raw 2m model
temperatures verifies best and those values are colder than our
official forecast and approach or break all time records for ORD
and MDW.

The GFS, GFS-FV3, GEM, and ECMWF 12z operational runs all continue
to drop 850mb temps to below -30C & in the case of the GFS to-
40C. To put this into perspective, using the SPC sounding climo
page, the coldest 850mb temp even observed in IL (ILX, DVN, RAN,
and PIA and dates as far back as 1949). Over the past couple days
there have been some minor run to run variations in how low 850mb
temps bottom out, but there has been a good deal of consistency of
850mb at least reach -30C. Even the 51 member ECMWF ensemble has
850mb temps reaching -30C over northern IL.

Assuming we have a fresh snow pack from Monday`s system, the stage
would be set for temperatures to really get out of hand and end up
colder than currently forecast. Initially, moderate to strong
northwest winds look to send wind chills bottoming out in the -35
to -50F range late Tues night into Wednesday. Some minor
improvement in wind chills is expected Wed night into Thursday
morning, due primarily to diminishing winds. Also worth noting
that the 35 to 50 below wind chills are based on the somewhat
conservative official forecast temps, but should the colder raw 2m
model temps verify we could see wind chills approaching 60 below
in the coldest areas and with most of the CWA reaching close to 50
below.

There is still time for model guidance to back off on the
intensity of Arctic air mass. Keeping that in mind, I felt quite
comfortable with the more conservative temperature forecast. It is
much easier and preferred to slowly trend a forecast closer to
all time records this far out, rather than jumping out forecasting
all time records only to later have to back off on those extremes
if model guidance trends less severe with the cold.

To put this cold into perspective some, during the past 20 years,
Chicago has only had a sub zero high temp twice and only 22 times
in the past 100 years. Our current forecast has air temps below
zero between 40 and 60 hours across most of the CWA, which a much
longer period of sub-zero wind chills.

While still very cold, temps do look like they will begin to
moderate Friday.

- Izzi

&&

.CLIMATE...

Here are the record lows and record cold highs for next week`s
cold...

                     Tue Jan 29   Wed Jan 30   Thu Jan 31
   Chicago
Record Low           -16 (1966)   -15 (1966)   -12 (1985)
Record Low Max        -6 (1966)     3 (1966)     1 (1971)

   Rockford
Record Low -20 (1966)   -19 (1966)   -18 (1966)
Record Low Max  -9 (1966)    -3 (1951)    -3 (1996)

   Chicago
All Time Record Low:      -27 (Jan 20, 1985)
All Time Record Low Max:  -11 (Jan 18, 1994 & Dec 24, 1983)

   Rockford
All Time Record Low:      -27 (Jan 10, 1982)
All Time Record Low Max:  -14 (Jan 18, 1994 & Jan 6, 1912)

- Izzi
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Chambana

Chambana

Posted
Posted

We really need these few clippers to pan out between now and Tuesday to tap into the true potential of this airmass. Im not to optimistic. Despite decent radar returns right now, not a flake in the air, dry air is wining the battle. Monday is borderline as we warm into the mid to lower 30s before the bottom falls out. 

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cyclone77

cyclone77

Posted
Posted

The ferocity of the arctic air mass looks extremely impressive, but the longevity of it is almost more impressive.  The Euro verbatim has us go below zero Monday night, and not get back above zero until Sunday.  Not sure what the longest we've been below zero, but that's gotta be close to a record at the least.  

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Hoosier

Hoosier

Posted
Posted
8 minutes ago, cyclone77 said:

The ferocity of the arctic air mass looks extremely impressive, but the longevity of it is almost more impressive.  The Euro verbatim has us go below zero Monday night, and not get back above zero until Sunday.  Not sure what the longest we've been below zero, but that's gotta be close to a record at the least.  

For Moline, the record is 4 days from 1/31/1996 through 2/3/1996.  There have been 5 occurrences of 3 days and 4 occurrences of 2 days.

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donsutherland1

donsutherland1

Posted
Posted

Earlier today, the temperature reached -6° in Chicago. That was Chicago's coldest temperature since January 2, 2018 when the mercury fell to -9°. A much colder air mass could move into the region by the middle of next week. If some of the guidance is accurate, Chicago could experience its lowest temperature in more than 25 years.

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RogueWaves

RogueWaves

Posted
Posted
On 1/24/2019 at 2:08 PM, Hoosier said:

I have trouble with wunderground these days so maybe somebody can check, but didn't the -27 at Chicago on 1/20/85 occur at like 9 am?  So it doesn't necessarily have to be a nighttime min temp if you bring the coldest pool of air overhead during a different time of day.

Yep. KRMY hit -22F Monday morning about 8:30, well after sunrise

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toddrix1977

toddrix1977

Posted
Posted
23 minutes ago, donsutherland1 said:

Earlier today, the temperature reached -6° in Chicago. That was Chicago's coldest temperature since January 2, 2018 when the mercury fell to -9°. A much colder air mass could move into the region by the middle of next week. If some of the guidance is accurate, Chicago could experience its lowest temperature in more than 25 years.

Some of the guidance is showing all time low temps and all time low max.

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Roger Smith

Roger Smith

Posted
Posted

In the source region (for next week's mega cold) at present time, Shepherd Bay (Nunavut) reports -56 F (-48.6 C) which is close to its all-time record low. I notice on the latest guidance that the 474 dm thickness crosses into MN and WI and reaches Chicago before being squeezed out of the air mass. This may back off closer to the time, but even 486 dm thickness would be very unusual at that latitude. 

Shepherd Bay is near the base of the Boothia Peninsula on the arctic mainland around 70 deg N. It is not some frost hollow location like Mayo, Yukon. 

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