Dec 29-Jan 2 potential storm event

[janetjanet998]

2 hours ago, StormChaser4Life said:

Nice to see you back man! It's been too long. Last significant ice I remember here in my county was like 2009 I think. Have had icing events since but they didn't pan out well or weren't excessive. Definitely nervous that temps could surge above freezing. Daytime ice events can be tricky. But I like we maintain northerly sfc flow which should help.

90% of the time a thin tongue of warmer  air  somehow creeps in from the SE and the event ends sooner than expected , at least for the city

This is especially true for daytime events...

I recall many times tracking these things and noticing the temp in Lincoln has gone from 31 to 34 in the past two hours

before you know it the airport is 33 and rain

.I can't explain why...maybe just luck ..

now there has been some huge ice storms further south along I-72 over the years including ones on the northern edge a an Ohio River event and ones staying all ZR down there for a system while we got snow

 

 

[Hoosier]

7 minutes ago, sbnwx85 said:

Already down to 20 at KSBN thanks to some local clearing overhead.

Down to 20 here as well, colder than forecast and colder than any model had.  Given the proximity of the high, it makes sense why.  But again, these little things will start to matter at some point, at least in terms of ground impacts, because now we'll have to rise all the way back through the 20s instead of starting out at 25 or something.

Interestingly, the 00z HRRR is colder here and now has temps AOB freezing until like 21z.

[McHenrySnow]

Found my model. 

[Natester]

From LSX:

 

AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
823 PM CST THU DEC 31 2020  
   
UPDATE  
  
ISSUED AT 804 PM CST THU DEC 31 2020  
  
A BAND OF WINTRY PRECIPITATION HAS MOVED NORTH INTO SOUTHEAST  
MISSOURI AND THE FAR SOUTHERN REACHES OF THE CWA AHEAD OF THE  
PREVIOUS FORECAST. THIS BAND IS EXPECTED TO MAKE IT TO THE ST.   
LOUIS METRO/COLUMBIA METRO REGION AROUND 04Z. WHILE THE LEADING  
EDGE OF THIS PRECIPITATION COULD START AS SNOW OR A WINTRY MIX, IT  
IS ANTICIPATED TO QUICKLY TRANSITION TO FREEZING RAIN. FREEZING  
RAIN HAS BEEN REPORTED IN FARMINGTON, MO WITH THIS FIRST BAND.  
  
A BRIEF BREAK IN PRECIPITATION IS POSSIBLE AFTER THIS FIRST SHOT  
OF WINTRY MIX/FREEZING RAIN, HOWEVER THE GAP IN REFLECTIVITY HAS  
BEEN FILLING IN OVER THE PAST HOUR. I CANNOT RULE OUT LIGHT  
PRECIPITATION FALLING IN THE GAP BETWEEN THE FIRST ROUND OF  
PRECIPITATION AND THE SECOND, MORE ROBUST ROUND OVERNIGHT.  
  
MRM  

 

In other words, it's moving an hour ahead of schedule.

[Cary67]

10 minutes ago, McHenrySnow said:

Found my model. 

That band is a bit tight. Won't complain though if that verifies

 

[fluoronium]

23 minutes ago, janetjanet998 said:

90% of the time a thin tongue of warmer  air  somehow creeps in from the SE and the event ends sooner than expected , at least for the city

This is especially true for daytime events...

I recall many times tracking these things and noticing the temp in Lincoln has gone from 31 to 34 in the past two hours

before you know it the airport is 33 and rain

.I can't explain why...maybe just luck ..

now there has been some huge ice storms further south along I-72 over the years including ones on the northern edge a an Ohio River event and ones staying all ZR down there for a system while we got snow

 

 

Yeah I've noticed this too. It can't just be selective memory either since it's been over a decade since the last big ice storm in central IL. Any decent ice threat seems to get killed off by warm air creeping in further than expected. This time the model support is pretty strong though, and even the NAM is on board now. So if I get 33 and rain most of the day tomorrow, I'm going to be irritated

[WeatherMonger]

ILX late evening update

 

Quote

Area Forecast Discussion
National Weather Service Lincoln IL
857 PM CST Thu Dec 31 2020

.SYNOPSIS...
Issued at 846 PM CST Thu Dec 31 2020

Freezing rain will overspread central Illinois late tonight and
continue into Friday morning, though a changeover to rain is
likely in areas south of I-72 by late morning. The ice, mixed with
sleet and snow at times, is expected to continue into the
afternoon northwest of the Illinois River, before the storm system
moves northeast in the evening and takes the precipitation with
it. While much of central Illinois will reach the lower to mid 30s
by afternoon, areas south of I-70 should see highs well into the
40s.

&&

.UPDATE...
Issued at 856 PM CST Thu Dec 31 2020

Plenty of dry air sampled on our evening balloon sounding, but
this should moisten quickly from the top down as our storm system
lifts northeast. Mid evening radar imagery shows the leading edge
of the echoes across the southern third of Missouri, with surface
reports showing is freezing rain. Latest HRRR shows this precip
shield reaching Springfield and Decatur toward 2-3 am and the
Peoria metro toward 6 am.

Main concern will be with timing of any switchover to rain. HRRR
keeps the freezing precip continuing past midday north of I-72,
while the newly arrived 4km NAM and the ARW/NMM switch it over by
midday as far north as Bloomington. Stiff low level northeast wind
flow and frozen ground add some concerns that the slower solution
may be the way to go, though precip rates may be heavy enough that
latent heat release may compensate. Will keep a rain or freezing
rain mix continuing along and west of I-55 into the afternoon with
a switchover in eastern Illinois.

Still looking like a widespread quarter to third inch of ice
accumulation across the warning area, with a tenth or two of ice
southeast of there. No changes will be made to headlines at this
time.

 

[Crispus]

5 minutes ago, fluoronium said:

So if I get 33 and rain most of the day tomorrow, I'm going to be irritated

If this were snow, I'd be right with ya. Ice, though...I don't have a problem with forecasts being wrong about ice storms, especially with my driveway being about 15 degrees from being vertical (slight exaggeration). 

[Hoosier]

Even ORD, a place that has a hell of a time radiating, has dipped to 20.

Would be interesting to do a 00z upper air analysis compared to models to see if this is just a surface temp thing or if the 925 mb layer is running colder than progged.

[StormfanaticInd]

The storm behind this is sneaking up on us

[Hoosier]

9 minutes ago, StormfanaticInd said:

The storm behind this is sneaking up on us

 

On 12/30/2020 at 11:11 AM, Hoosier said:

Watch out for a couple things

1) possibility of a thump of snow on the leading edge

2) the wave immediately following behind.  Has a shot to be a little consolation somewhere.

I was all over it before it was popular.

[Chicago Storm]

40 minutes ago, Hoosier said:

Even ORD, a place that has a hell of a time radiating, has dipped to 20.

Would be interesting to do a 00z upper air analysis compared to models to see if this is just a surface temp thing or if the 925 mb layer is running colder than progged.

Comparing the 0z DVN sounding to the 0z RAP and 0z NAM for that location, they are running ~2C too warm at 925mb.

[StormfanaticInd]

28 minutes ago, Hoosier said:

 

I was all over it before it was popular.

Its a decent threat. Especially for my area 

[McHenrySnow]

47 minutes ago, Hoosier said:

Even ORD, a place that has a hell of a time radiating, has dipped to 20.

Would be interesting to do a 00z upper air analysis compared to models to see if this is just a surface temp thing or if the 925 mb layer is running colder than progged.

Down to 14º here. 

[Hoosier]

Strictly in my backyard, this ice setup is at least as good as the one on 2/11-2/12, 2019... imo.

Some factors were more favorable in the 2019 event and some look more favorable in this one.  We had the massive arctic outbreak about a week and a half prior in 2019, but the immediate lead in (as in just hours before precip onset) is actually colder this time.

[Radtechwxman]

1 hour ago, janetjanet998 said:

90% of the time a thin tongue of warmer  air  somehow creeps in from the SE and the event ends sooner than expected , at least for the city

This is especially true for daytime events...

I recall many times tracking these things and noticing the temp in Lincoln has gone from 31 to 34 in the past two hours

before you know it the airport is 33 and rain

.I can't explain why...maybe just luck ..

now there has been some huge ice storms further south along I-72 over the years including ones on the northern edge a an Ohio River event and ones staying all ZR down there for a system while we got snow

 

 

Yea unfortunately you're right. Wondering if that has to due to urban heat island effect and maybe influence from the river. Most models keep us around freezing but daytime ice events have high bust potential. We shall see. Definitely our best potential we had since the one back in 2008.

[Hoosier]

4 minutes ago, StormChaser4Life said:

Yea unfortunately you're right. Wondering if that has to due to urban heat island effect and maybe influence from the river. Most models keep us around freezing but daytime ice events have high bust potential. We shall see. Definitely our best potential we had since the one back in 2008.

If any daytime marginal temp ice event can work, it's one that is only a week and a half after the solstice.  At least you have a morning onset of precip.

[Radtechwxman]

7 minutes ago, Hoosier said:

If any daytime marginal temp ice event can work, it's one that is only a week and a half after the solstice.  At least you have a morning onset of precip.

I been monitoring the observations versus hrrr modeled temps. Overall isn't too off. I did see we dropped to 22 earlier but up to 25 now. Hopefully that will level out and not keep rising. ENE wind should hopefully keep that in check.

[Hoosier]

Any thoughts on this RC?  Fairly cold look for the LOT cwa at 21z.

[sbnwx85]

Not for nothing, the WPC has upped the probability of MBY getting to .25” of ice to 50%.

[Harry Perry]

17 minutes ago, Hoosier said:

If any daytime marginal temp ice event can work, it's one that is only a week and a half after the solstice.  At least you have a morning onset of precip.

Have a strange feeling we (where precip onset is later) will manage to escape anything too severe due to the time of day and sun angle... even only a week and half after the solstice. If we were 27-28° it’d be a different story but a balmy 32° - just isn’t going to cut it, and that’s okay 

[Winter Man]

2 hours ago, McHenrySnow said:

Only managed 24º today and down to 17º. I just want snow, please, weather gods, just some straight up snow. 

"But I say to you, Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven. For he makes his sun rise on the evil and on the good, and sends rain snow on the just and on the unjust."

Please Jesus please...

[Hoosier]

9 minutes ago, Harry Perry said:

Have a strange feeling we (where precip onset is later) will manage to escape anything too severe due to the time of day and sun angle... even only a week and half after the solstice. If we were 27-28° it’d be a different story but a balmy 32° - just isn’t going to cut it, and that’s okay 

Precip rates are always something to consider, but they are probably even more important in the daytime.  If your rates are light, I have a hard time believing it would struggle to accrete even at 31-32.

[Harry Perry]

20 minutes ago, Hoosier said:

Precip rates are always something to consider, but they are probably even more important in the daytime.  If your rates are light, I have a hard time believing it would struggle to accrete even at 31-32.

Stop and say it ain’t true... 

 

Sorry, the Jameson and Ginerales have taken over. That being said, for all of our sakes, I hope everyone has a good New Year. 


edit** 

and accretion levels stay in check. 

[cyclone77]

You can go ahead and pencil me in for the 03z RAP.  

 

[RCNYILWX]

Any thoughts on this RC?  Fairly cold look for the LOT cwa at 21z.

I think it's definitely plausible north except probably right near the lake, even south can't rule it out. Question there is does the latent heat release from the warmer rain drops eventually win out for southern areas. Recalling the 2019 ice storm, the expected warming above freezing didn't happen during the steady precip because winds stayed northeast the whole time and the surface wet bulb zero line struggled to advance northward. That'll be the key to watch tomorrow is the surface wet bulb zero line.

 

 

 

[Hoosier]

54 minutes ago, RCNYILWX said:

I think it's definitely plausible north except probably right near the lake, even south can't rule it out. Question there is does the latent heat release from the warmer rain drops eventually win out for southern areas. Recalling the 2019 ice storm, the expected warming above freezing didn't happen during the steady precip because winds stayed northeast the whole time and the surface wet bulb zero line struggled to advance northward. That'll be the key to watch tomorrow is the surface wet bulb zero line.

 

 

 

Down to 12 at DPA.  

A little unclear on just how far north the more sig ice gets since sleet looks like a player, but we didn't have temps like this in the hours immediately before 12/28/15 or 2/11/19.  Untreated surfaces will be a nightmare.

[Radtechwxman]

23 minutes ago, Hoosier said:

Down to 12 at DPA.  

A little unclear on just how far north the more sig ice gets since sleet looks like a player, but we didn't have temps like this in the hours immediately before 12/28/15 or 2/11/19.  Untreated surfaces will be a nightmare.

Meanwhile my temp keeps creeping up and is a few degrees warmer than hrrr depicts now. I'm nervous. Lol

[Hoosier]

13 minutes ago, StormChaser4Life said:

Meanwhile my temp keeps creeping up and is a few degrees warmer than hrrr depicts now. I'm nervous. Lol

Gonna be a tight one.  If you do break above freezing, I don't think it will be in time or by enough to prevent some issues.

[Jackstraw]

This is a bit surprising, or not lol. Freezing level is really really shallow already, maybe 2k feet.  Depth of the warmth is under 700 mb right now.  Models had it deeper yesterday.....