Arguably the biggest holiday of the year is fast approaching - now within two weeks - and the question many already want to know is what are the chances "I" see a white Christmas?
Well, like all things weather related the answer isn't easy this far away. Lets take a look at some things below.
First, what are the statistical odds you'll see a white Christmas. The official definition is 1" of snow on the ground.
Those of you in the north stand a greater chance, for obvious reasons.
There are a couple ways a white Christmas can be accomplished. Snow already on the ground, or fresh snow falling. If only life were a movie it would happen each year right?
We've had some snow lately, but we've had some rain. Lets take a look at the approximate snowpack that remains across the state.
Spotty at best, and snow across the southern areas typically doesn't stick around too long.
On the bad news side of things, all indications point to a mild pattern coming ahead. Much deserved, but will eradicate the existing snowpack except for those piles in mall parking lots that Jeep owners love to park on to justify their mods. Temps are generally looking to average 5-10 degrees above the norms in the week leading up to Christmas. Many of the global models agree in this overall pattern.
The CPC has even issued a very warm outlook for this upcoming period, and for good reason.
So based on all this, it is unfortunately not looking too good. There appears to be little in the way of precip during this time and what does fall will probably take on the form of rain given the milder temperatures. Any snow that falls during the lows overnight will quickly melt thereafter.
The glim of hope:
Just before the holiday, this pattern is currently forecast to dramatically flip to a west coast troughing pattern - such a pattern typically promotes an active storm track.
We can see the period on the models, but unless youre new here (welcome, by the way) you should know how extremely unreliable they are 7 days away let alone 14.
If you're a snow lover youll want to root for today's 6z GFS run, which buries much of the state ON Christmas Day.
Did I mention the models are unreliable and flaky at this range? Are you reading or just looking for pretty pictures? The quickest way to get on ISC's naughty list is to buy into this stuff when other pages share it with no real explanation other than "its just one model run."
Sorry if I just got your hopes up, but here is the same models run just 6hrs later at 12z (6am)
aaaaaaaaaaaaaaaaand here is the most recent run at 18z (12pm)
This is why you should not EVER buy into a facebook page, or any sort of outlet posting a big snowfall map. Because just a few hours later it can vanish. Right now there is zero reason to believe any of these runs are more accurate than the other. The fact the models do hint at a pattern change with an active storm track around the holiday will offer hope for those wanting a white Christmas.
Otherwise, unfortunately right now I would say its not looking too good. Of course we here at ISC will keep you posted as we get closer!
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Good evening Illinois residents. Its been a bit more of a nuisance week weather wise than earlier anticipated with very light freezing drizzle and "mood" snows occurring that were not well modeled at all.
Tomorrow (Thursday December 6th) we will see a better advertised system move across Central and Southern Illinois. This will bring an area of light accumulating snow throughout the day. Totals won't amount to much, generally an inch or less but a few spots that manage to cash in on a heavier band of snow could see a little more. The below map uses a 10:1 ratio to calculate snow amounts. More importantly is it shows WHERE the snow will fall, and generally it won't amount to a whole lot.
Of bigger concern to many is the potential for a bigger winter storm to move in over the weekend. Earlier this week we made mention this could be a big storm, and while it will be for other parts of the country, recent model trends have shifted the worst of it south.
What once looked like a big hit for central and southern Illinois now just appears it may be a graze for the very southern part of Illinois. Still, we are 3-4 days away and its not written in stone. In fact, some of the major models are still way different in solutions where the system will strike first - across Oklahoma and Texas. The NAM model is the most aggressive, dumping record amounts of snow across Oklahoma and showing quite the ice storm in parts of Texas. The GFS and EURO, however, show much tempered amounts of more so of a rain event.
Right now it is still hard to nail down what will happen there, let alone across Illinois a day later. We can just note the trends though and update our forecast accordingly. This trend was first noticed yesterday, and more so confirmed today.
NAM model showing a similar storm track, but also a more expansive snow on the back side.
Regardless of what happens, the trends seem to be showing this will be an I-64 and south event, if anything. We'll have to watch the storm track closely, as it will be a pretty potent system and any shifts in the track could easily mean the difference between 0 and 6 inches of snow, or ice VS no ice. Stay tuned!
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A blizzard one week followed by a tornado outbreak the next week. Typical Illinois weather mood swings am I right? Once again after a fairly quiet week, we may be facing another bigger weather maker over the weekend.
Overall temperatures will be seasonably cold, but not extreme. Friday morning appears to be the coldest morning with some parts in the north dipping down into the teens.
A weak disturbance moving through Thursday morning could bring some light snow accumulations across central Illinois. Another weekend system could bring more winter weather to the state. Right now this appears to be focusing on southern Illinois.
Early morning Thursday system bringing light snow to central Illinois and light rain showers south. We're not expecting any serious accumulation but some spots could pick up an inch or two.
Friday morning lows as predicted by the GFS
Here is a look at the weekend weather system. Right now it looks like it will bring a rain/snow mix to the southern half of Illinois. We'll be watching the track to iron out the details as the event progresses.
There is our week ahead, for whatever reason we seem to be stuck in a pattern loop where the bigger weather systems arrive on the weekends. Not sure if this is a good or bad thing!
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(12:00PM - 12/1/18) A brief/quick update on the expected severe t'storm threat across portions of the state today. Everything seems on track from the prior update, with just minor placement changes on our severe weather threat TAM.
A storm system moving through the region will help set the stage for a late season severe weather event across portions of the state today. By mid-afternoon a cold from will be sweeping east from Western Missouri into Western and Southwest Illinois. Ahead of this front will be a moderately favorable environment for this time of year. This environment will feature moderate instability (1000-1500 CAPE), moderate moisture (Upper 50's dew points), favorable upper level environment, a nice push of higher lapse rates, and nicely curved hodographs.
Scattered thunderstorms will develop in the vicinity of the front across portions of Western Missouri, Western and Southwest Illinois this afternoon. This activity will push northeast across portions of Central and Southern Illinois through the rest of the afternoon and evening, posing a severe threat. All modes of severe weather will be possible, including a tornado threat, given a favorable environment. All of this activity will weaken and the severe threat will end, as it pushes into Northern and Eastern Illinois by early Saturday night.
Below is our final and latest updated severe weather threat TAM. Only minor placement changes were made since the last update.
A tornado watch is in effect until pm across portions of central, western and southern Illinois. Clearing skies and warming temperatures beneath a pocket of very cold air aloft will promote the development of thunderstorms this afternoon across these areas.
Additionally, wind shear is quite strong as the mid and upper level jets wrap around a tight area of low pressure moving in from the plains.
Here are the watch details.
ILLINOIS COUNTIES INCLUDED ARE
ADAMS BROWN CALHOUN CASS CHRISTIAN DE WITT FULTON GREENE HANCOCK JERSEY KNOX LOGAN MACON MACOUPIN MASON MCDONOUGH MCLEAN MENARD MONTGOMERY MORGAN PEORIA PIATT PIKE SANGAMON SCHUYLER SCOTT
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 434 NWS Storm Prediction Center Norman OK 215 PM CST Sat Dec 1 2018 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Central Illinois East-central Missouri
* Effective this Saturday afternoon and evening from 215 PM until 700 PM CST. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible
SUMMARY...Thunderstorms are forming along the Mississippi River, and will spread northeastward across the watch area this afternoon. A few storms may become severe, capable of damaging winds, hail, and perhaps a few tornadoes. The tornado watch area is approximately along and 60 statute miles east and west of a line from 25 miles northeast of Peoria IL to 65 miles south southwest of Springfield IL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings.
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(12:15AM - 12/1/18) Given recent snows and colder temperatures across the state the past several weeks, severe weather is the last thing on the mind of most, but the threat exists Saturday into Saturday night across portions of the state.
A storm system moving through the region will help set the stage for a late season severe weather event across portions of the state. By afternoon a cold from will be sweeping east from Western Missouri into Western and Southwest Illinois. Ahead of this front will be a moderately favorable environment for this time of year. This environment will feature moderate instability (1000-1500 CAPE), moderate moisture (Upper 50's dew points), favorable upper level environment, a nice push of higher lapse rates, and nicely curved hodographs.
Scattered thunderstorms will develop in the vicinity of the front across portions of Western Missouri, Western and Southwest Illinois during the afternoon. This activity will push northeast across portions of Central and Southern Illinois through the rest of the afternoon and evening, posing a severe threat. All modes of severe weather will be possible, including a tornado threat, given a favorable environment. All of this activity will weaken and the severe threat will end, as it pushes into Northern and Eastern Illinois by early Saturday night.
Below is our latest updated severe threat TAM. You may notice the severe threat extends across some areas impacted with high snowfall totals during the recent blizzard, where snow still exists on the ground.