WeatherMonger

Everything here melting on contact pretty much, even with moderate snow earlier. Just had a heavy band come in that I could hear from inside. Thought it was raining, looked out and it was pouring snow and graupel. Got a coating on elevated surfaces and light dusting on the grass in about 4 minutes. Stopped as fast as it started.

1 hour ago, purduewx80 said:

I wouldn’t go that far. “Convection” does not mean lightning and thunder are always involved. The convective profile would need to favor cloud tops at or colder than -30C for sufficient charge separation, and there isn’t much evidence of that in current guidance. At least locally, cell motions do not look all that rapid. Steering flow is only 5-15KT, so I think some of these will end up producing surprise amounts tomorrow, especially near any enhanced surface convergence. Nowcasting will have to involve looking for local “heating”, upper level vort max support and any surface troughing, which is similar to what we look for when forecasting thunderstorms in the summer. 

Gotcha, I'm an enthusiast rather than student. I seen "cellular" and c9nvective both in there to make that assumption. Win some and lose some

Thanks for the clarification.

ILX mentioning potential for thundersnow, not expecting much accunulation, if any but would make for an even trade.

Quote

.LONG TERM...(Friday through Wednesday)
ISSUED AT 149 AM CST Thu Jan 14 2021

The snowfall forecast will remain tricky through Friday as the
surface low remains parked over the Quad Cities. Most locations
across the forecast area will receive less than 1" as the best
dynamics and thermodynamics for widespread snowfall remain too far
west. Meanwhile across central Illinois, numerous light snow
showers will develop between early Friday morning and Friday
afternoon. These snow showers will be cellular, exhibiting some
convective elements given the steep low-level lapse rates. While
most of these cellular snow showers will be light, it is possible
a couple of them could be heavy. The thermal profile beneath the
cold core of the upper-level low will exhibit appreciable amounts
of omega within a saturated DGZ at times. This could potentially
lead to very brief periods of white out conditions, but will only
last minutes rather than hours with these scattered cells moving
across the region at a fast clip.

Since the snowfall across central Illinois will be mesoscale-
driven instead of synoptically-driven, we strayed away from the
global snowfall solutions (NAM, GFS, CMC, and ECMWF). Instead, we
leaned toward the short- term HiRes models (HREF, HRRR, etc) to
paint the better solution for estimated snowfall for Friday. This
put most of the forecast area at an inch or less, with very isolated
1-3" totals throughout the region

Airport reported 2.2", had just over 3" at my house

Better late than never......

6 minutes ago, Chicago Storm said:

ILX needs a short fuse warning.


.

?

Easily going to be the biggest snow of the year/season here.

Ground is completely covered now,  closing in on an inch easily. Still pouring snow

Pouring snow right now

Wow, takes a lot get a pic uploadable... 

Solid coating here,  guesstimate 1/2" currently.

All back end snow from yesterday had melted and most icing had dropped but not all.

Just switched to snow here. Ice wasn't too bad, roads are fine now after warming up

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.

34 minutes ago, WeatherMonger said:

Hope HRRR is off it's rocker. Would be devastating for SW to East Central MO and wouldn't want that here either.

 

 

 

NAM comes in less bullish yet still alarming. I'll take all the ice they can give if the power stays on. 

Hope HRRR is off it's rocker. Would be devastating for SW to East Central MO and wouldn't want that here either.

6 minutes 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.

I can't root this one on, not this year lol.

I'm just glad there is something to follow for a change, been a very boring year of weather here. Add in everything else going on and I just need an escape 

1 minute ago, fluoronium said:

That's the first ice storm warning in likely over a decade for many of those ILX counties, mine included. I'm going to try getting some time lapses of the accumulating ice.

I know the NAM seems to be the outlier with the northward extent of the warm air, but every recent shot at ice IMBY has always been killed by warmer than modeled temps. Even so, at least a few hours of freezing rain looks to be nearly certain here, so it should be enough to make the trees sparkly.

Yeah, I can't remember the exact year of the last one but it was definitely over 10 years ago. I'm thinking 2007 for some reason. Think we ended up with around .3" here and can't remember if that was the one that hit Jacksonville pretty hard with closer to .6" or if it was another system.

We've definitely been overdue though.

ILX with a rather detailed AFD for a change

Quote

.SYNOPSIS...
Issued at 417 PM CST Thu Dec 31 2020

Clouds will continue building overnight, as the next weather
system moves into the Midwest. This system will build from the
south and progress northward through Illinois overnight through
Friday. Freezing rain is expected on the leading edge, with Ice
Storm Warnings in effect for portions of central Illinois, while
Winter Weather Advisories are in effect for much of the remainder
of Illinois. Hazardous, and dangerous conditions, will persist
through Friday, with the possibility of power outages around the
area. As the system tracks through southern portion of Illinois,
rainfall should begin taking over across southeast Illinois, while
a mixed precipitation continues northwest of the I-55 corridor.
This system exits Friday night, however with another system
tracking through the southeast US Saturday, this could bring light
precipitation to the Midwest as excessive moisture remains.

&&

.SHORT TERM...(This evening through Friday night)
ISSUED AT 417 PM CST Thu Dec 31 2020

Lots to discuss, therefore the late products:

A deep upper level trof is carrying a large Low pressure system
across the far southern Plains, near the Gulf of Mexico off the se
Texas coastline. This is the system that will track northeast
through the overnight, impacting central Illinois and the Midwest
to ring in the new year. Currently looking at sfc observations and
seeing most locations throughout central and southern Illinois
sitting below freezing. This is the key component to precip type
for the overnight moisture. As the Low pressure system lifts
through the Mississippi River Valley, the excessive moisture
content will continue to lift with the core. With some precip
already edging out ahead of the system, this will work through
moistening up the lower atmosphere and continue leading
precipitation northward. Forecast soundings indicate that although
the sfc temperatures will be below freezing at the onset of
precip, the mid level will be much warmer. This will melt all
frozen precip in the mid levels, however as this falls, the level
near the sfc will be below freezing. This depth appears to only be
in excess of maybe 2kft, which would not typically be enough to
provide a full refreeze of water droplets. As these still liquid
droplets reach the below freezing ground (as indicated by frost
depth readings from this morning), they will freeze on contact.
Frost depth readings this morning, in areas where Ice Storm
Warning is in effect were from 1-6 inches deep. Here at the ILX
office, we reported a 4 inch depth this morning. This is
sufficient enough for freezing rain development. The leading edge
of this system is expected to fall as all freezing rain overnight
into Friday morning. With heaviest precipitation arriving towards
morning north of the I-72 corridor, this is highlighted as the
best chance for ice accumulations up to 0.40 inches of ice
accumulation possible. This will create dangerous and hazardous
conditions throughout the region, as travel would be nearly
impossible and damage to trees and power lines could create
widespread power outages. As the system tracks northward, warmer
air will begin to filter into the area Friday morning into the
afternoon, changing freezing rainfall to rainfall...however this
is only expected to occur se of the I-55 corridor. Mixed precip is
expected from the I-55 corridor through the Illinois River Valley.
Nw of the Illinois River Valley is forecast to remain cold enough
that freezing rain will likely prevail, before a change to
snowfall as the backside of the Low pressure system begins
shifting to the lower Great Lakes late Friday night. This could
bring up to two inches of snowfall around GBG, while decreasing to
near 1 inch along a line extending from Rushville to Peoria. This
system is forecast to be out of the area by 06-09z Saturday
(late Friday night).

Been too long, it was coming at some point.

New WPC Ice Accrual map

We're running about 3-5 degrees below forecast highs today. Doesn't look like we'll get above freezing

ILX late morning AFD update.

Quote

.UPDATE...
Issued at 1103 AM CST Thu Dec 31 2020

Looking over much data this morning, there appears to be a favor
towards slightly shifting the track of tonight`s system to the
southeast. This would introduce the highest icing potential
between the IL River Valley and say around I-72. This track would
also include an increase in snowfall across the nw portion of the
CWA from the IL River Valley nw. Rainfall will still persistent
across the se CWA, however the chance for light freezing rain at
the onset is possible. Will continue to monitor models, and
complete the afternoon package with changes to the Winter Storm
Watch/Advisory. Did discuss the potential for Ice Storm product,
however this is not used as much as Winter Storm products

Watch until 10 here. Be nice to hear thunder

Quote

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0238 PM CDT Mon Aug 10 2020

   Valid 102000Z - 111200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
   ILLINOIS...SOUTHEAST WISCONSIN...NORTHWEST INDIANA...FAR SOUTHWEST
   LOWER MICHIGAN...

   ...SUMMARY...
   A derecho producing significant damaging winds will persist across
   much of northern Illinois and possibly far southern Wisconsin, and
   into northern Indiana and southern Lower Michigan this evening.

   ...Northern IL...southeastern WI...northern Indiana...southwestern
   Lower Michigan...
   A Derecho will continue east across northern Illinois, at speeds
   around 60 mph. Many reports of 60-80 mph winds have been recorded
   along with a few over 100 mph as it moved across Iowa and crossed
   the MS River, with some areas experiencing long duration of severe
   winds over 50 kt.

   The environment remains favorable ahead of the Derecho as
   temperatures continue to warm. Modified midday soundings show steep
   midlevel lapse rates and MLCAPE over 3000 J/kg. This will prove
   sufficient to maintain a severe wind threat through the Chicago
   area, including northwest Indiana and parts of Lower Michigan.

   For more information see mesoscale discussions 1455 and 1456.

   ..Jewell.. 08/10/2020