November 15 Snow/Ice Chance

[H2O]

2 minutes ago, showmethesnow said:

We were oh so close though. Little better cooperation at 500 mbs and we would have probably seen our snowstorm especially in the burbs.

500 and the HP up north.  A sliding high over NE that gets to Maine won't cut it in Nov.  If it got stuck in NY/Canada then I'd trust the colder model runs.  But getting east of us lets too much Atl air in upstairs which is not so good for I95 dwellers

[psuhoffman]

29 minutes ago, mappy said:

Ava Marie has 2-4” for the northern areas, higher amounts as you go west. I think 2” is a good call for my backyard.

That's about where I am. But this has high bust potential both directions. The whole thermal boundary is close. And models can't usually nail every level to to the exact degree. In this case a 1-2 defree miss in either direction for us is the difference between mostly just cold rain/sleet and 5" of snow. 

[osfan24]

I'm also hoping that this thing slides in a couple hours earlier than expected, which could help. It seems models keep pushing up the arrival of precip, and these types of storms often beat that arrival time anyway.

[nj2va]

Maybe it’s just me but it’s seemed the overall mood here has been realistic with expectations in the metros. I don’t think anyone was buying 5” of snow in DC on Nov 15. 

A couple hours of frozen before rain sounds good to me. 

[winterymix]

If some areas get an inch of sleet starting just before sunrise and continuing after sunrise, the collision repair shops are going to have all the business they can handle and then some.  With so many models showing the 850 mb warm nose with strong cold air damming, couldn't prolonged sleet be a real factor from Mappy land to Winchester?  Prolonged snow is less likely because warm noses are hard to deny with such strong dynamics.

I think climatology suggests snow before the warm nose arrives, (quick front end thump) and then sleet for four to eight hours a change to rain and a brief episode of frozen at the tail end.  All this for the area west of I-95 out to I-81.

The trend is our friend, models are shifting slightly cooler run after run.

[psuhoffman]

22 minutes ago, showmethesnow said:

Don't think I have seen it. But it seems reasonable enough with what we are seeing within the models themselves. Such a marginal situation especially in the upper levels that just a little colder solution would probably mean a world of difference on what snow we see. Really no reasoning (except maybe the fact that the models have seemed to have a warm bias so far this fall) but more a feeling, I tend to believe we will see the models trend a touch colder.

I've felt this current iteration of the gfs since the last major overhaul has run warm in marginal snow situations most of the time. Just an observation and I know that can be dangerous without looking at the data to back it up. 

[WxUSAF]

14 minutes ago, psuhoffman said:

That's about where I am. But this has high bust potential both directions. The whole thermal boundary is close. And models can't usually nail every level to to the exact degree. In this case a 1-2 defree miss in either direction for us is the difference between mostly just cold rain/sleet and 5" of snow. 

It does have bust potential, but I would go off our climo and past experience. Low level cold holds on longer than expected, but mid-level warmth comes in faster than expected.  That’s a recipe for a lot of sleet I think. I’m thinking that snow may be restricted to your area and the mountains, with the rest of us just going sleet to rain. Hope I’m wrong and see a few fatties, but I’m leaning against it right now.

[showmethesnow]

12 minutes ago, psuhoffman said:

That's about where I am. But this has high bust potential both directions. The whole thermal boundary is close. And models can't usually nail every level to to the exact degree. In this case a 1-2 defree miss in either direction for us is the difference between mostly just cold rain/sleet and 5" of snow. 

Going to be a nightmare for forecasters. But what else is new when it comes to the mid-Atlantic region. But what else can you expect with such marginal temps where just a little difference in dew points can mean the world of difference.

[showmethesnow]

2 minutes ago, psuhoffman said:

I've felt this current iteration of the gfs since the last major overhaul has run warm in marginal snow situations most of the time. Just an observation and I know that can be dangerous without looking at the data to back it up. 

There have been so many overhauls in recent years i can no longer keep track of what to expect/bias's with the GFS. 

[midatlanticweather]

22 minutes ago, psuhoffman said:

That's about where I am. But this has high bust potential both directions. The whole thermal boundary is close. And models can't usually nail every level to to the exact degree. In this case a 1-2 defree miss in either direction for us is the difference between mostly just cold rain/sleet and 5" of snow. 

Should always bet a fail with climo.. I am ready for a system to break our way again... Hope fail is not the outcome 

[psuhoffman]

6 minutes ago, showmethesnow said:

There have been so many overhauls in recent years i can no longer keep track of what to expect/bias's with the GFS. 

It's significantly more accurate now but in some ways it was easier to use back when it sucked but had consistent biases that you could correct for. All the models have become less predictable in their errors imo. Or maybe I just don't have the time I used to to stare at them all day and learn them. 

[psuhoffman]

14 minutes ago, WxUSAF said:

It does have bust potential, but I would go off our climo and past experience. Low level cold holds on longer than expected, but mid-level warmth comes in faster than expected.  That’s a recipe for a lot of sleet I think. I’m thinking that snow may be restricted to your area and the mountains, with the rest of us just going sleet to rain. Hope I’m wrong and see a few fatties, but I’m leaning against it right now.

Yea I would lean that way. I've been downplaying it for people at work in Baltimore. My previous thoughts were for my area and Mappy. I think for things to break right will take a bit more down towards 95 but even there it's possible a thump to start can overcome the mid level waa for a period and put down 1-3" real quick before the flip. I've seen that happen plenty of times. But the safe bet is sleet for sure. 

[mappy]

36 minutes ago, psuhoffman said:

That's about where I am. But this has high bust potential both directions. The whole thermal boundary is close. And models can't usually nail every level to to the exact degree. In this case a 1-2 defree miss in either direction for us is the difference between mostly just cold rain/sleet and 5" of snow. 

I didn't look too closely yesterday as i took the day off and went to visit my kid at school. Looking today, just at the GFS, there is quite the warm nose around 850 to deal with. If the precip comes in hot and heavy, like others have mentioned, then perhaps that column can cool completely. But soundings, at least for my backyard, are pretty damn sleety for tomorrow. 

with that said, I am going to take a laptop home tonight and perhaps work from home tomorrow to see what happens. don't want to miss the first wintry event!

[smokeybandit]

Gonna be a real fun commute tomorrow.  Either the roads will be bad, or the drivers will drive like the roads are bad since they haven't seen a snowflake yet this season.

[Wonderdog]

41 minutes ago, showmethesnow said:

We were oh so close though. Little better cooperation at 500 mbs and we would have probably seen our snowstorm especially in the burbs.

So based on what I've been reading this AM, and I already know this to be true, a better pass south of current forecasts at H5 would make a world of difference for the majority on this feed. So does that make the climo argument moot since it's not really climo that is the problem but the positioning of the players?

[Wonderdog]

5 minutes ago, smokeybandit said:

Gonna be a real fun commute tomorrow.  Either the roads will be bad, or the drivers will drive like the roads are bad since they haven't seen a snowflake yet this season.

Ain't that the truth.

[showmethesnow]

11 minutes ago, Wonderdog said:

So based on what I've been reading this AM, and I already know this to be true, a better pass south of current forecasts at H5 would make a world of difference for the majority on this feed. So does that make the climo argument moot since it's not really climo that is the problem but the positioning of the players?

Better pass south and a quicker solution with the closed low and we would have seen a better interaction with the coastal low. Not to mention that we would have seen a fresh supply of cold air infused into the system overhead in time to catch the back end of the storm. As far as climo and positioning of players pick your poison because they both have merit.

eta: Just consider this with the climo and positioning of players. If we would have seen this occur just 2-3 weeks later in the season we would probably be talking snowstorm. Just a degree or 2 would make all the difference in the world.

[Chris78]

Should be interesting to see which model is more correct between the GFS and Euro. That's a big difference between the models for the time frame of 7am - 3pm tomorrow. I think it just really shows how much a marginal set up this is with  just 1 to 2 degrees difference between the 2 models for a majority of the storm.

[WxUSAF]

6z euro went toward the gfs apparently.

[osfan24]

4 minutes ago, WxUSAF said:

6z euro went toward the gfs apparently.

Not that surprising. The Euro has been a joke with snowstorms for our area since the upgrade. It was laughably bad with the late-season snowstorm last year. It seems to run too cold and count way too much ice as snow. It's no longer the King.

[ErinInTheSky]

4 minutes ago, osfan24 said:

Not that surprising. The Euro has been a joke with snowstorms for our area since the upgrade. It was laughably bad with the late-season snowstorm last year. It seems to run too cold and count way too much ice as snow. It's no longer the King.

Euro wasn't all that great with tropical this year either. GFS honestly was holding its own.

[Scraff]

5 minutes ago, osfan24 said:

Not that surprising. The Euro has been a joke with snowstorms for our area since the upgrade. It was laughably bad with the late-season snowstorm last year. It seems to run too cold and count way too much ice as snow. It's no longer the King.

Until the king is right again, send it to the dungeon. Dilly dilly!

Ok. I’m ready for my mangled white rain now.

[paulythegun]

Question: Is climo actually an issue here? Decent amount of cold air. Seems like we just have an over-amped ULL that doesnt dig enough and quickly overwhelms the cold column.

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[mappy]

2 minutes ago, paulythegun said:

Question: Is climo actually an issue here? Decent amount of cold air. Seems like we just have an over-amped ULL that doesnt dig enough and quickly overwhelms the cold column.

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if it were the middle of the december instead of november, our current air mass probably would be colder, colder grounds, etc. it makes it easier to put down a really good front end thump when its already cold vs hoping the cold gets in fast and hangs around for a bit. mid-november storms where people see warning level snows isnt all that common in our area. 

[Eskimo Joe]

Feels like snow outside.  Thicc cirrus layering up the sky.  Bring it...even if it's a 3 hour front end thump of slush on the grass, bring it.  

[Jandurin]

Funny, I was thinking it felt too warm.

[Bob Chill]

Prob lowering my bar with the 12z suite. Instead of 1" of slush on the patio table I'll go with the sound of sleet on the window with the blinds closed 

[BristowWx]

1 minute ago, Bob Chill said:

Prob lowering my bar with the 12z suite. Instead of 1" of slush on the patio table I'll go with the sound of sleet on the window with the blinds closed 

yes just hoping to see a frozen water droplet for a few minutes. Regardless, not much sleep for anyone tonight.  I am sure most of us will be awake watching and waiting to report that first mangled flake that we imagine we see in the porch light at 4 am but turns out to be dryer lint.

[Eskimo Joe]

The past 2 winters really have done a number on people.  Too many in full desperation mode for a pre-season event. 

[midatlanticweather]

33 minutes ago, paulythegun said:

Question: Is climo actually an issue here? Decent amount of cold air. Seems like we just have an over-amped ULL that doesnt dig enough and quickly overwhelms the cold column.

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Climo is always an issue here... but others answered well.. there is much more warmth to overcome going into cold season than going out! This was quite a cold air mass to get the cold to southern Texas with snow, but we have a lot of warm moist land in the east moderating the airmass, a warm ocean, and the source of the cold is not a snow packed region or frozen ground yet. So a lot to overcome!