Let's Talk Winter!!

[pondo1000]

11 minutes ago, buckeye said:

so OHweather, an actual meteorologist,  gives his time to put together the potential scenarios for this event and this is your feedback?    

...and you wonder why most folks here in our sub consider you a d-bag.

I think he just responds like this for attention. If we just ignore him, maybe he’ll go away. LOL

[AppsRunner]

10 hours ago, OHweather said:

I think a swath of moderate snow (3-6”) is likely across a good portion of central and southern Ohio...

All signs point to a boatload of QPF with outstanding upper level divergence, high PWATs advecting in, very strong low to mid level warm air advection and isentropic lift, and strong frontogensis.  

Question mark is obviously ptype.  With plenty of room to wet bulb cool as the precip arrives and what should be very strong lift, think it’s likely most areas north of the Ohio River flip to a few hours of snow...though it may initially start as sleet and surface temps won’t be that cold.  Strong lift will slow the advance of the mixing for a time, though with how strong the WAA is it will eventually overwhelm, so it may be hard for anyone to see more than 4-6 hours of all snow.  

Given the sensitivity to temps and rates here, hard to be very confident in big snows for a large area.  I think there’s enough juice for warning criteria somewhere but it may be the exception rather than the rule.  The low and mid levels aren’t that cold so it will be a wet snow.  I’d like to see model soundings show a better “cross hair signature” (lift in the snow growth zone) for better confidence in 6”+ snow.  Right now the idea of a few hours of moderate to heavy QPF as snow but with questionable ratios limits how aggressive I can go to 3-6”, but it could be an exciting 3-6” and there is some boom potential.  My guess is the jackpot may be central and east central Ohio. 

Either way it’s tricky and though I’m fairly optimistic for someone to get a decent thump, trends during the day Tuesday leading up will make or break it. 

11

How's this one?

Obviously very marginal thermals below 850, but I'd favor a zone of 3-6" wherever they can hold on to snow long enough. The NAM is obviously overdone, but something like the 3km NAM doesn't seem too far fetched. 

[OHweather]

14 minutes ago, AppsRunner said:

How's this one?

Obviously very marginal thermals below 850, but I'd favor a zone of 3-6" wherever they can hold on to snow long enough. The NAM is obviously overdone, but something like the 3km NAM doesn't seem too far fetched. 

Ha, better than what I glanced through last night.  The 12z NAM was more cross-hairy in central OH later tonight than the 0z last night.  It's almost certainly overdone, but there's a pretty good signal for an advisory to borderline warning criteria thump (3-6")...question will be where exactly.  Thermals are iffy but evaporational/dynamic cooling should be enough for a time and rates will be there.  NAMs are both north of most guidance and suggest north of I-70 does best, others are a bit farther south. 

[buckeye]

26 minutes ago, pondo1000 said:

I think he just responds like this for attention. If we just ignore him, maybe he’ll go away. LOL

true

As far as tonight.  I think 2" minimum is a lock if it comes in as snow....and that's mainly because it comes in with such a thump.   How much more depends on how quickly the warm takes over.   What's interesting is that usually heavy thumping precip stays as snow until the thumping let's up and the dynamic cooling ends.   Most models are showing a pretty steady and heavy onslaught of precip coming in like a wall without many breaks.  I think high end could top 6" if it's a strong relentless thumping.    Going to be strange to see heavy snow transition to heavy rain.  Usually don't see that, it's usually heavy snow transitioning to sleet and then light rain or drizzle.    

Should be interesting if nothing else.   Not a good sleeping night.   

[pondo1000]

49 minutes ago, buckeye said:

true

As far as tonight.  I think 2" minimum is a lock if it comes in as snow....and that's mainly because it comes in with such a thump.   How much more depends on how quickly the warm takes over.   What's interesting is that usually heavy thumping precip stays as snow until the thumping let's up and the dynamic cooling ends.   Most models are showing a pretty steady and heavy onslaught of precip coming in like a wall without many breaks.  I think high end could top 6" if it's a strong relentless thumping.    Going to be strange to see heavy snow transition to heavy rain.  Usually don't see that, it's usually heavy snow transitioning to sleet and then light rain or drizzle.    

Should be interesting if nothing else.   Not a good sleeping night.   

Would like to see a heavy thumping. Although once again, I’ll be sleeping while it snows!!! Can we get a daytime snow for once? LOL

[JayPSU]

Even now the GFS has nothing for us.  Just odd.

[HighTechEE]

2 hours ago, buckeye said:

so OHweather, an actual meteorologist,  gives his time to put together the potential scenarios for this event and this is your feedback?    

...and you wonder why most folks here in our sub consider you a d-bag.

My sentiments EXACTLY!

[Snowless in Carrollton]

1 hour ago, pondo1000 said:

Would like to see a heavy thumping. Although once again, I’ll be sleeping while it snows!!! Can we get a daytime snow for once? LOL 

How can you sleep when this very possibly could be the last decent snow until next winter ?

[pondo1000]

18 minutes ago, Snowless in Carrollton said:

How can you sleep when this very possibly could be the last decent snow until next winter ?

LOL

[OHweather]

Here's my guess.  Confidence is obviously lower than normal.  I'm confident in a 3-6" band but not confident on southern extent, and there is an all or nothing element to this type of event. 

Everything still supports a lot of QPF and the expectation is that wet bulbing/dynamic cooling will slow the northern translation of the change to rain enough to allow for a decent accumulation of snow.  I'm thinking that as it comes into Ohio the precip starts changing to sleet/snow and farther north mainly snow.  The heaviest precip appears to be between 3 AM and 9 AM from west to east as a band of convection wraps into the frontogenetically forced band of precip across central Ohio...hi-res models are explicitly showing QPF rates of 0.10-0.25"+ per hour when that occurs.  Soundings are close to supporting thunder in central and southern Ohio in that window.  Strong lift in the DGZ and a deep layer close to freezing in the low-level may allow for large, aggregated dendrites during that convective snow.  That is the precip that should slow the northern progression of the mixing while it occurs and may even cause areas to flip back to sleet or snow a bit farther south.  However, it is a short window with little margin for error.  The mesoscale forcing isn't as strong in northern Ohio, though vort advection aloft and very strong upper-level ventilation into a near record-strong jet streak to the north/northeast will allow light to moderate snow (with fewer thermal profile issues) to extend north into all of northern Ohio.

My thinking is that the precip comes into Ohio as sleet/snow...near and north of I-70 it likely is mostly snow at the onset due to plenty of room to wet-bulb.  Farther south may start as sleet/snow and try going to rain quickly, but then possibly flip back to snow as the convection and heavy rates work through closer to dawn.  This is the area of most uncertainty.  It's possible the US 50 corridor including Cincinnati and Athens doesn't flip back to snow during the heavy precip and sees little if any accumulation...though if they do flip even for an hour or two they may quickly get 2-4".  Along I-70 there isn't much margin for error but I feel better about them being mainly snow during the heaviest precip...farther north confidence does increase quite a bit.  Because the temp gradient is oriented more WNW-ESE, it wouldn't be surprising if heavy snow occurs a bit farther south over eastern Ohio than western Ohio.  Given the dynamics, QPF and rates I'm quite confident in a band of 3-6" occurring somewhere north of I-70 where it's all snow, so the bust potential along and south of that corridor (including Columbus and especially Dayton) has more to do with questions over ptype during the heaviest burst.  There has been a slight tick north today which makes southern Ohio even more questionable than it was off the bat.

In terms of what the ceiling is, hi-res models are showing intense lift in the DGZ with the convective precip around sunrise...if that can fall as all snow for more than 2-3 hours someone can probably rip off a quick 8"...but good luck forecasting that.  If I had to guess where it would possibly be, somewhere in Delaware/Licking/Morrow/Knox/Holmes/Coshocton/Tusc/Guernsey Counties would probably have the best shot.

Good luck in your respective back yards!

[HighTechEE]

58 minutes ago, OHweather said:

Here's my guess.  Confidence is obviously lower than normal.  I'm confident in a 3-6" band but not confident on southern extent, and there is an all or nothing element to this type of event. 

Everything still supports a lot of QPF and the expectation is that wet bulbing/dynamic cooling will slow the northern translation of the change to rain enough to allow for a decent accumulation of snow.  I'm thinking that as it comes into Ohio the precip starts changing to sleet/snow and farther north mainly snow.  The heaviest precip appears to be between 3 AM and 9 AM from west to east as a band of convection wraps into the frontogenetically forced band of precip across central Ohio...hi-res models are explicitly showing QPF rates of 0.10-0.25"+ per hour when that occurs.  Soundings are close to supporting thunder in central and southern Ohio in that window.  Strong lift in the DGZ and a deep layer close to freezing in the low-level may allow for large, aggregated dendrites during that convective snow.  That is the precip that should slow the northern progression of the mixing while it occurs and may even cause areas to flip back to sleet or snow a bit farther south.  However, it is a short window with little margin for error.  The mesoscale forcing isn't as strong in northern Ohio, though vort advection aloft and very strong upper-level ventilation into a near record-strong jet streak to the north/northeast will allow light to moderate snow (with fewer thermal profile issues) to extend north into all of northern Ohio.

My thinking is that the precip comes into Ohio as sleet/snow...near and north of I-70 it likely is mostly snow at the onset due to plenty of room to wet-bulb.  Farther south may start as sleet/snow and try going to rain quickly, but then possibly flip back to snow as the convection and heavy rates work through closer to dawn.  This is the area of most uncertainty.  It's possible the US 50 corridor including Cincinnati and Athens doesn't flip back to snow during the heavy precip and sees little if any accumulation...though if they do flip even for an hour or two they may quickly get 2-4".  Along I-70 there isn't much margin for error but I feel better about them being mainly snow during the heaviest precip...farther north confidence does increase quite a bit.  Because the temp gradient is oriented more WNW-ESE, it wouldn't be surprising if heavy snow occurs a bit farther south over eastern Ohio than western Ohio.  Given the dynamics, QPF and rates I'm quite confident in a band of 3-6" occurring somewhere north of I-70 where it's all snow, so the bust potential along and south of that corridor (including Columbus and especially Dayton) has more to do with questions over ptype during the heaviest burst.  There has been a slight tick north today which makes southern Ohio even more questionable than it was off the bat.

In terms of what the ceiling is, hi-res models are showing intense lift in the DGZ with the convective precip around sunrise...if that can fall as all snow for more than 2-3 hours someone can probably rip off a quick 8"...but good luck forecasting that.  If I had to guess where it would possibly be, somewhere in Delaware/Licking/Morrow/Knox/Holmes/Coshocton/Tusc/Guernsey Counties would probably have the best shot.

Good luck in your respective back yards!

Awesome post!  I'm almost in the nowcasting mode with the radars lighting up SW of our region, someone could get thundersnow tonight in the I-70 corridor, similar to what you stated, rates could be like 3" per hour for very short times! To bad most of us will be fast asleep if it occurs!

[vespasian70]

Loving the 00z HRRR for MBY. Nearly 6".

However, this kind of setup has huge bust potential for my neck of the woods. Fingers crossed!

[dilly84]

10 minutes ago, vespasian70 said:

Loving the 00z HRRR for MBY. Nearly 6".

However, this kind of setup has huge bust potential for my neck of the woods. Fingers crossed!

Nam sticking with a foot lol

[vespasian70]

18 minutes ago, dilly84 said:

Nam sticking with a foot lol

TT is a hot mess when it comes to mixed precip types and snow totals. If this system gives Newark a foot of snow I'll ride up to Apple Valley on my Unicorn and buy you dinner.

(I secretly hope its right!)

[dilly84]

21 minutes ago, vespasian70 said:

TT is a hot mess when it comes to mixed precip types and snow totals. If this system gives Newark a foot of snow I'll ride up to Apple Valley on my Unicorn and buy you dinner.

(I secretly hope its right!)

Well it has 3k NAM with what looks like up to 3" an hour rates. Wouldn't take much at that pace to get a lot of snow. Patiently watching the radar. 

[dilly84]

I'm blown away that no WSWs have been put up. The fact that some areas could see 3" an hour rates with tomorrow being a weekday, and the impact that would have is crazy to me that they'd all stick with an advisory

[vespasian70]

13 minutes ago, dilly84 said:

I'm blown away that no WSWs have been put up. The fact that some areas could see 3" an hour rates with tomorrow being a weekday, and the impact that would have is crazy to me that they'd all stick with an advisory

ILN have updated their snow fall maps many many times today, a hint that they may be a bit gun-shy in issuing anything more than an advisory at the moment. To that point, the setup is incredibly tricky.

 

[OHweather]

In terms of warnings it is debatable.  There is no where near the required 80% confidence in 6”+ occurring in any given spot (even if it’s possible, it’s not that confident)...but based on impacts an argument could be made that several counties near I-70 particularly near/E/NE of Franklin could be upgraded on an impact based basis.  Even that is a little flimsy as confidence still isn’t great, though at this point most signs are pointing towards that area getting hit reasonably hard for a few hours. 

[dilly84]

12 minutes ago, OHweather said:

In terms of warnings it is debatable.  There is no where near the required 80% confidence in 6”+ occurring in any given spot (even if it’s possible, it’s not that confident)...but based on impacts an argument could be made that several counties near I-70 particularly near/E/NE of Franklin could be upgraded on an impact based basis.  Even that is a little flimsy as confidence still isn’t great, though at this point most signs are pointing towards that area getting hit reasonably hard for a few hours. 

Yea, the criteria is what it is, but I'd have to think NWS can also issue one if the impact will be great enough. I know I'll be up all night to see what happens.

[chuckster2012]

Very heavy snow coming home tonight through Columbus, Indiana. Laid down a quick inch. Home now in N. Vernon and it's quickly changed to a mix..

[Buckeye1994]

Very heavy snow for over an hour now here just south of Dayton, picked up well over an inch. Still all snow, can’t hear any ice pellets mix in yet 

[HighTechEE]

12 minutes ago, Buckeye1994 said:

Very heavy snow for over an hour now here just south of Dayton, picked up well over an inch. Still all snow, can’t hear any ice pellets mix in yet 

Ditto, same here on the SE side of Dayton, some of the heaviest snow of the winter right now, very heavy flakes coming down in chunks, you can tell tho the end is near!

[vespasian70]

Not a single flake here yet. Didn't know there was so much dry air to overcome.

[vespasian70]

27 minutes ago, vespasian70 said:

Not a single flake here yet. Didn't know there was so much dry air to overcome.

Pouring very fine flakes now.

[dilly84]

Nam and hrrr still looks good

[dilly84]

Dayton has to be rocking right now 50dbz high chance of thundersnow there.

[OHweather]

Dayton airport (which is N of downtown) reported 1" of snow last hour.

Per the correlation coefficient (CC), the heavier precip moving into Cincinnati is attempting to flip things back for snow.  For Cincinnati not sure if this ends up doing anything, but farther north along southern cutoff it might make a difference and was needed to get the southern edge of the heavier snow to work out.   The precip moving WSW-ENE out of southern IN is convective and has some lightning, and is what would bring the heaviest rates to OH.  I think Columbus hangs on long enough to see snow during this, but it's still close...much more certain a little north. 

A narrow portion of southern OH may do well with freezing rain as some stations have already gone to it south of route 50 and still have modest dry air advecting in...could see some spots crack 0.10" ice accumulation. 

[vespasian70]

06z HRRR has Newark in the bullseye. lol

 

[chuckster2012]

54 minutes ago, OHweather said:

Dayton airport (which is N of downtown) reported 1" of snow last hour.

Per the correlation coefficient (CC), the heavier precip moving into Cincinnati is attempting to flip things back for snow.  For Cincinnati not sure if this ends up doing anything, but farther north along southern cutoff it might make a difference and was needed to get the southern edge of the heavier snow to work out.   The precip moving WSW-ENE out of southern IN is convective and has some lightning, and is what would bring the heaviest rates to OH.  I think Columbus hangs on long enough to see snow during this, but it's still close...much more certain a little north. 

A narrow portion of southern OH may do well with freezing rain as some stations have already gone to it south of route 50 and still have modest dry air advecting in...could see some spots crack 0.10" ice accumulation. 

Thunder and lightning here in SE Indiana rn. Rain/ 33°..

[OHweather]

Just now, chuckster2012 said:

Thunder and lightning here in SE Indiana rn. Rain/ 33°..

Yeah, a good chunk has gotten into SW OH too the last half hour or so.  The CC line on radar is trying to fight back near Dayton and Columbus, so we'll see if the dynamic cooling can happen.  Mixing did get rather far north quickly with much of Columbus currently mixing... someone is going to get drilled and it'd be nice if it can be a majority of our central Ohio posters in this thread and not just the northern folks.