White Christmas Blizzard 2022

[tron777]

Please continue all Thurs / Fri storm discussion here! Here's to a White Christmas for all AV Posters!

[tron777]

Latest thoughts from the boys which makes perfect since and matches the tone here. A lot of our big systems start as rain and change to snow. It's tough to get an all snow solution here like March of 2008 those are rare. You need the cold air in here first. In this case, the storm is developing on the leading edge of the cold air.

Main story in the extended period continues to be the potential
for very cold temperatures along with deep low pressure
developing in the eastern United States.

Initially, zonal mid-level flow and a lack of deep moisture
make for a dry start to the work week. A dampening shortwave
along with a weak (and dry) cold front pushes through the Ohio
Valley Tuesday, but otherwise below normal temperatures will
occur through Wednesday.

Starting Thursday, there is high uncertainty in the progression
and intensity of a low pressure system across the eastern half
of the United States. Latest runs are generally slower with the
arrival of arctic air to the Ohio Valley. In addition, surface
low location spans from Michigan in the warmer ECMWF to the
Appalachians/east coast in the colder GFS. For now, will stay
with an ensemble- informed blended solution, which brings a
rain/snow mix to our CWA ahead of the low on Thursday before the
arctic blast arrives Friday.

Will need to continue to track this unfolding situation as we
head toward the busy holiday travel period. While an
accumulating snow forecast isn`t possible with any confidence
right now, there is much higher confidence that gusty winds and
very low wind chills will commence late this coming week and
continue through the weekend.

[tpweather]

Thanks Les and I posted in the other section earlier this morning and will post here in the future and may guess is I will throw out a post or two in the next several days lol.

[tron777]

Just to carry over from the December thread... overnight guidance has 3 solutions for this system:

CMC / Euro / EPS: Cutter with rain to snow
OP GFS / GEFS: Either an Apps Runner or a low that transfers to an East Coast Low. That model can't decide which solution right now.

We'll just have to wait and see. It's all on how each model handles the Pacific and the placement and ridge axis of the +PNA Ridge. The energy is now over the Bering Sea and it is strong... wow! It's being forced up and over the AK Range thanks to the -EPO.

IR_loop.gif

[tpweather]

Just to carry over from the December thread... overnight guidance has 3 solutions for this system:

CMC / Euro / EPS: Cutter with rain to snow
OP GFS / GEFS: Either an Apps Runner or a low that transfers to an East Coast Low. That model can't decide which solution right now.

We'll just have to wait and see. It's all on how each model handles the Pacific and the placement and ridge axis of the +PNA Ridge. The energy is now over the Bering Sea and it is strong... wow! It's being forced up and over the AK Range thanks to the -EPO.


IR_loop.gif

What a great view and this shows exactly what I talked about the other day how both Alaska and the central and eastern USA can be cold at the same time. Alaska has had some nice snows in the recent week and they are staying cold with this pattern. Getting that flow west of Alaska up and over the poles which in turn will send down the polar air. We don't see this every year which imo makes it that much tougher to get an accurate forecast this far out but again by Monday or Tuesday we should see the polar air heading south and the good thing is much of the area it will traveling over has snow on the ground

[Bgoney]

This is old news to everyone in AVLAND, but a great summary of the thought process here and thought process of KIND Mets, here is their AFD from this morning


Thursday through Saturday(Potential Winter System)...

Latest guidance continues to signal towards the potential for an
impactful low pressure system to pass through the Ohio Valley
sometime between Thursday morning and Friday. With that said, there
is significant variability amongst both ensemble members and various
deterministic runs during the 00Z issuance Saturday.

******************************************
Differences in Deterministic Solutions: *
******************************************

First, lets discuss the deterministic runs. The GFS has continued to
be an outlier, mainly due to the position of the ridge axis over
the Western CONUS. The american model has the ridge axis over the
intermountain west, leading to a shorter wavelength and therefor a
neutrally tilted amplified trough over the Midwest. This solution
would result in more impacts over the eastern US versus the Midwest.
Of note is a slightly weaker thickness gradient prior to
cyclogenesis. With the high likelihood of a rather anomalous cold
sector within this system this leads to the belief that this
solution may be misleading.

On the other hand is the remainder of the deterministic suite
(Canadian, ECMWF, UKMET). These three are much more aligned on the
ridge axis placement further west over the Pacific Coast. In return,
the wave length is larger, allowing for a more positively tilted
upper trough and less subtropical jet influence. The polar jet in
this instance in piece-wise with a strong jet streak upstream of the
trough and a supergeostrophic jet streak near the ridge over the
Northeast. A couple jet streak provides an efficient environment for
surface cyclogenesis, as seen near the surface of these various
solutions. All three of these solutions also seem to better
represent the anomalous Arctic air expected in the cold sector,
increasing baroclinicity and the rate of surface pressure depletion.
This is not to say that these solutions will end up being the result
next week, but the meteorological interactions over the 150 hours of
output do have plausible explanations.

**********************************
Ensemble and Probabilistic Output: *
**********************************

These deterministic solutions can help dissect the probabilistic output
given through various ensemble members of each parent model. With
the conceptual model chosen (longer wave length, positively tiled
trough, coupled polar jet), we can narrow the expected solutions to
those that align. There is still a wide range of solutions even
through this process, but this does show a trend of some sort of
deep surface cyclone over the Midwest, Ohio Valley, or Tennessee
Valley Thursday into Friday. This leads to a greater likelihood of
an impactful winter storm within the vicinity of central Indiana.
The track of the surface low will still have a significant influence
on the severity and type of impact central Indiana will witness. Any
track south of central Indiana will lead to a greater chance of
significant snow fall, whereas north or through central Indiana will
limit snow, but increase rain and even thunderstorm chances.

This process also shows a wide array of temperature outcomes for
late next week, ranging from low 50s in the warm sector, to mid 20s
in the cold sector. For now, temperature forecasts are more aligned
with the ensemble mean, but the result with much more likely be on
the lower or higher extremes (10th or 90th percentile).

********************************
Winter Storm Brief Conclusion: *
********************************

Through a diagnostic synoptic process, discussed above, trends are
leaning towards an impactful low pressure system with a low track
ranging from Chicago to Nashville. Many potential solutions and
outcomes remain in play including the potential for significant
snowfall sometime between Thursday morning and Friday. There are
still many factors that will influence the forecast in the coming
days. Behind this system will be an influx of extremely cold Arctic
air. Morning lows late next week are likely to be in the single
digits. Stay weather aware as this system approaches and check back
for updates.

[tpweather]

Bgoney I read that this morning and a wonderful write up to say the least. We have parts of the huge high that will break off before late next week and this as well can make a difference. Do we see a 1025 or 1040 high break off and sit over the mid-west. Again the Euro and CMC is at the lower end and the gfs higher. Do I have any ideal at the moment and the answer is no. If this was more of a Canadian cold outbreak I would already be leaning heavy on the Euro as we have seen this play out many times. The cross-polar air mass is one thing that will be the wild card. No doubt we are going to see a cold air mass but to what extent is just way to early in the ballgame.

[tron777]

Great posts guys! A great AFD from Indy too. Had to see who wrote it, was hoping it was Mike Ryan (former ILN Met) but it wasn't. Anyway, that's a great write up and shows the uncertainty that we are dealing with. I believe in the next 48 to 60 hours, we'll know if this thing will Cut, run the Apps, or do the East Coast transfer. IMO with such an anomalous pattern any solution is plausible at this range (Day 5).

[tron777]

Ok guys... keep the discussion going! I'll check back in when I can.

[tron777]

The energy for this system should be approaching the West Coast (thinking near Seattle) by about Tuesday evening. Until the 0Z Wed runs start, we'll see some model swings still.

[tron777]

When watching guidance today, keep an eye on the PNA ridge. If it's off the coast, it'll cut West of us. On the coast then the Apps. Inland then it's too far east.

[mainevilleweather]

Indy gets blasted on this run. East this morning and west this afternoon. Can't wait to see the 18z!

[tron777]

12z GFS is West. Low comes over us and bombs out in NW Ohio. Still a wild solution! PNA ridge is off the West coast.

[mikeyp]

I wouldn’t be shocked to see future runs take the low further east but nothing can be ruled out I suppose! Nice run though especially for Indy!

[mainevilleweather]

I wouldn’t be shocked to see future runs take the low further east but nothing can be ruled out I suppose! Nice run though especially for Indy!

I'd rather continue to see the low where is rather than the east coast atm.

[mikeyp]

Canadian doesn’t look to bad either. Nice 4-6” snow!

[Bgoney]

GFS basically trending to the EU solution

[AddisonJM]

I don't think the GFS is done shipping this thing west. Yesterday I thought we were over 50% odds of having some snowcover, now I'm not so sure we see anything more than mood flakes. The Euro isn't wanting to dig as deep before the low winds up and if that trend continues we'll struggle to see much more than dry air.

[tron777]

I agree... The GFS is in correction mode. How far West is the question.

[tpweather]

Good Afternoon and let model mayhem begin or continue. So the gfs made a move westward and that was expected. In a 12 hour period it goes from 1002 to 980 and that is no doubt a bombed out system. The path is Nashville to Cincinnati to Lima. This storm is still moving north/northeast even with the bombing out. This is a wonderful run if you want a rather wicked storm. The cmc on the other hand is quicker and goes from 1008 to 990 in a 12 hour period so yes its bombing out but not quite like the gfs and the path is Evansville to Cincinnati to Youngstown so a more northeast path. That would be wonderful for Indy but we would still get over 4 inches. No matter what happens the wind and cold will be a big issue without any snow. The Euro seems to follow the CMC and lets see in an hour or so if this hold true.

[tron777]

Gefs still has the Apps runner that transfers.

[tron777]

In my opinion the goal.posts are narrowing for the storm track. Chicago to the Apps in play.

[airwolf76]

I am glad this has trended away from a coastal huger I do not want it i have plans the entire last week of the month and any significant snowfall would completely ruin it for me. i really hope this thing blasts the OV or midwest. i will be rooting you on

[tpweather]

Les I don't have Chicago in the mix. This storm will dig with this kind of arctic air mass. Want to see the Euro but my guess is it will be more in line with the CMC and having the low digging in southern Illinois or western Kentucky and then bombing out. When you get a storm to bomb out and its still heading north/northeast that means cold air is wrapping in quickly to the system. Give me the gfs today and call it a day. We still have a few more days and so far I am seeing the cold on the move from Siberia which is key and heading towards western and central Canada.

The system early in the week looks to be falling apart and I must call uncle and will miss that system. I though an inch might work but the energy from both systems never hook up plus they are not that strong to begin with. At the end of the day that part of the forecast is better for us in terms of the bigger system later in the week.

Funny thing is we call them app runners or cutters into the upper mid-west but this creature is somewhat different because if it truly bombs out like models are showing it really becomes neither of those two because of the way it moves.

[tron777]

I like those terms Tim because it's a good geographical marker kind of thing in regards to storm track. I left my goal posts fairly wide just in case. We need it to be SE of Cincy to get buried otherwise it's rain to snow. How much depends on storm track. I truly believe that we will be dealing with an intense low. Seen too many runs with that look.