Tracking the Late October Potential

[snowdude]

I'm driving to Hagerstown.

They look to get at least 2-4"

[Bob Chill]

True, but it will take a unknown amount of snow to cool the ground. Whereas if you have ground temperatures below 32F and get instant accumulation.

This topic gets beat up every year. It's about rates period. Snow in the grass barely comes into contact with the ground. Air temps in the mid 30's with mod rates will stick immediately even if the ground temp is 45.

[WxUSAF]

True, but it will take a unknown amount of snow to cool the ground. Whereas if you have ground temperatures below 32F and get instant accumulation.

Of course it's unknown, but it's not "several inches" worth. It's all about the RATE at which the snow is falling and the background atmospheric conditions. The average ground temperature in the first 6-12" of soil doesn't matter for squat. The snow is falling on the surface. The surface temperature can respond quickly to liquid thats at 33-34F.

No, just because you have ground temps <32F doesn't mean you get "instant accumulation". Thin cloud cover allowing sufficient light/heat through can keep things melting on contact, particularly on darker surfaces (e.g., roads). Also background humidity factors in.

There's a lot more that goes into it besides ground temps.

[EasternUSWX]

I'm driving to Hagerstown.

They look to get at least 2-4"

Ya I am thinking 4-7" there.

[WVclimo]

I'm driving to Hagerstown.

They look to get at least 2-4"

If you exit off 70 before Hagerstown, you can get up to Blue Ridge Summit pretty quickly. 1300' elevation in town, and a couple of decent restaurants/ bars. I think they'll do a lot better than HGR.

[Ian]

Of course it's unknown, but it's not "several inches" worth. It's all about the RATE at which the snow is falling and the background atmospheric conditions. The average ground temperature in the first 6-12" of soil doesn't matter for squat. The snow is falling on the surface. The surface temperature can respond quickly to liquid thats at 33-34F.

No, just because you have ground temps <32F doesn't mean you get "instant accumulation". Thin cloud cover allowing sufficient light/heat through can keep things melting on contact, particularly on darker surfaces (e.g., roads). Also background humidity factors in.

There's a lot more that goes into it besides ground temps.

you still get a good amount of melting. it was pouring snow down near the white house last yr in jan with temps a bit too warm and melting fast + compacting. there is probably a critical temp somewhere just above freezing but even there you're still going to run into terrible ratios caused by melting/compaction.

[real]

This topic gets beat up every year. It's about rates period. Snow in the grass barely comes into contact with the ground. Air temps in the mid 30's with mod rates will stick immediately even if the ground temp is 45.

This is true, but a lot certainly melts rather quickly from below when its a heavy wet snow with marginal ground temperatures, especially in urban areas. Believe it not, multiple inches of total accumulation was lost in Washington DC, and I imagine DCA, in both Feb. 5 2009 2010 and Jan 26, 2010 2011 because of that.

Also, remember how hard it was for the snow to stick on the afternoon leading up Feb. 5, 2010, despite fairly moderate snowfall rates? My basic point is yes, it will stick, but those who get concerned about such a thing each year are not total fools either.

[SN_Lover]

This topic gets beat up every year. It's about rates period. Snow in the grass barely comes into contact with the ground. Air temps in the mid 30's with mod rates will stick immediately even if the ground temp is 45.

It may "stick" but radiation being emitted from the ground will cause melting of an unknown magnitude from beneath, before ground temperatures reach at or below 32F. I received heavy snow last year when ground temps were relatively warm, and it did have a effect on accumulations.

[yoda]

Winter Storm Warning Garrett/Preston/Tucker

[WxUSAF]

you still get a good amount of melting. it was pouring snow down near the white house last yr in jan with temps a bit too warm and melting fast + compacting. there is probably a critical temp somewhere just above freezing but even there you're still going to run into terrible ratios caused by melting/compaction.

Right...AIR temps were a bit too warm. My point is that there is far more that goes into whether snow will accumulate or not than the ground temp. Ground temps are pretty easy to overcome, all things considered.

Get into discussion of ratios and it gets even more complicated since that is dependent on upper air temperatures and humidity levels creating different snow crystal structures, etc...

[Ian]

This is true, but a lot certainly melts rather quickly from below when its a heavy wet snow with marginal ground temperatures, especially in urban areas. Believe it not, multiple inches of total accumulation was lost in Washington DC, and I imagine DCA, in both Feb. 5 2009 2010 and Jan 26, 2010 2011 because of that.

Also, remember how hard it was for the snow to stick on the afternoon leading up Feb. 5, 2009, despite fairly moderate snowfall rates? My basic point is yes, it will stick, but those who get concerned about such a thing each year are not total fools either.

this is one of the weirder arguments that always pops up on teh board primarily because both sides are so strongly against eachother. it's definitely an issue but not a deal breaker per se.

[yoda]

So if the EURO model sides with the NAM lets say... who do we believe?

EURO/NAM vs GFS/RGEM?

UKIE/SREFs straddling that fine line?

[chris87]

So if the EURO model sides with the NAM lets say... who do we believe?

EURO/NAM vs GFS/RGEM?

UKIE/SREFs straddling that fine line?

i hope the euro goes the way of the GFS i'm already sick of this storm.

[wxmeddler]

This is going to be "mashed potato" snow... Even if you do get the rates enough to start sticking and accumulating, the snow is still going to be melting underneath. If you stuck a shovel in it the bottom 1" would be mush yielding ratios of like 6:1 or 8:1. The problem comes when even you clear the snow off the left over "mush" is going to freeze over the next night.. and the next..

[yoda]

i hope the euro goes the way of the GFS i'm already sick of this storm.

You aren't going to wait up for the 18z NAM/GFS?

Anyway, IMO, this EURO run is crucial. If it stays with the NAM, it gives a lil credence. If it bounces to the GFS, then its likely over. Unless it changes back later

[mappy]

You aren't going to wait up for the 18z NAM/GFS?

Anyway, IMO, this EURO run is crucial. If it stays with the NAM, it gives a lil credence. If it bounces to the GFS, then its likely over. Unless it changes back later

which we have all seen before... and we know how that ended up

[yoda]

Winter Storm Watch issued for Montgomery/Howard (more for the NW portions of the county FYI)

[Deck Pic]

So if the EURO model sides with the NAM lets say... who do we believe?

EURO/NAM vs GFS/RGEM?

UKIE/SREFs straddling that fine line?

there aren't camps....Not sure why people frame model runs like that.....

[Deck Pic]

You aren't going to wait up for the 18z NAM/GFS?

Anyway, IMO, this EURO run is crucial. If it stays with the NAM, it gives a lil credence. If it bounces to the GFS, then its likely over. Unless it changes back later

this post is a good reason why your post count should be much lower

[Ian]

this post is a good reason why your post count should be much lower

Yoda has been posting a stream of crap lately..

[real]

What is LWX seeing to NOW extend watches to Howard and Montgomery? Seems doubtful even places like Clarksburg in Northern Montgomery couldl reach 5 inches out of this?

[BethesdaWX]

there aren't camps....Not sure why people frame model runs like that.....

Groups of modeling favoring certain synoptical solutions?

[PhineasC]

Yoda has been posting a stream of crap lately..

Reading his posts really isn't that big of a deal. I get the idea the threads need to be policed.

[Bob Chill]

It may "stick" but radiation being emitted from the ground will cause melting of an unknown magnitude from beneath, before ground temperatures reach at or below 32F. I received heavy snow last year when ground temps were relatively warm, and it did have a effect on accumulations.

I'm not arguing about melting. I'm just saying that it can be 75 degrees the day before a storm and moderate+ rates with air temps in the mid 30's will stick pretty much within the hour. I"m not splitting hairs with ratios and melting and all that. Just stating it will accumulate. That is the biggest argument we get into every year.

Air temp is the most important. It can overcome surface temps very quickly. I had frost on my roof and had to scrape a car off this morning. The surface of the ground can respond almost as quickly.

But yes, above freezing ground will affect ratios. No arguing that. I'm just tires of hearing people say it won't stick because of warm ground. Heavy snow will stick right away. How long it stays around afterwards is mostly up to the air temp.

[weathercoins]

What is LWX seeing to NOW extend watches to Howard and Montgomery? Seems doubtful even places like Clarksburg in Northern Montgomery couldl reach 5 inches out of this?

Probably extra cautious. 4 inches from this storm will cause far more damage and disruption than 6 inches in a Jan or Feb storm, IMO

[Ian]

Reading his posts really isn't that big of a deal. I get the idea the threads need to be policed.

I post a lot (too much probably) but I never get why some people seem to enjoy a stream of consciousness way of interacting here. I like Yoda... he often adds to the conversation but I feel like all I see are "Ukie at 36: " or "Which camp do you like the best?" posts recently.

[VAsnowlvr82]

Yoda has been posting a stream of crap lately..

I dont think anything he has posted has been worthy of calling it crap!

[BethesdaWX]

Probably extra cautious. 4 inches from this storm will cause far more damage and disruption than 6 inches in a Jan or Feb storm, IMO

It only took 6" last January to triple the power outages achieved via snowmageddon. 4" of wet slush could surpass what we saw last January with some leaves still on the trees.

[yoda]

I post a lot (too much probably) but I never get why some people seem to enjoy a stream of consciousness way of interacting here. I like Yoda... he often adds to the conversation but I feel like all I see are "Ukie at 36: " or "Which camp do you like the best?" posts recently.

I was using the camps idea as something to see where the models lay, but if thats too much I will stop. The UKIE at 36 stuff was just so that people could see it, thats all. I try to add more than just the model image as thats what the Storm Mode requires

I will try to be careful with what I post

[SN_Lover]

I'm not arguing about melting. I'm just saying that it can be 75 degrees the day before a storm and moderate+ rates with air temps in the mid 30's will stick pretty much within the hour. I"m not splitting hairs with ratios and melting and all that. Just stating it will accumulate. That is the biggest argument we get into every year.

Air temp is the most important. It can overcome surface temps very quickly. I had frost on my roof and had to scrape a car off this morning. The surface of the ground can respond almost as quickly.

But yes, above freezing ground will affect ratios. No arguing that. I'm just tires of hearing people say it won't stick because of warm ground. Heavy snow will stick right away. How long it stays around afterwards is mostly up to the air temp.

I never said a location would not get accumulation. "It may "stick" but radiation being emitted from the ground will cause melting of an unknown magnitude from beneath".

This is going to be "mashed potato" snow... Even if you do get the rates enough to start sticking and accumulating, the snow is still going to be melting underneath. If you stuck a shovel in it the bottom 1" would be mush yielding ratios of like 6:1 or 8:1. The problem comes when even you clear the snow off the left over "mush" is going to freeze over the next night.. and the next..

@ Bob Chill I'm saying the snow accumulation ratios would get effected, because of radiation being emitted from the ground. You might get accumulation but a UNKNOWN amount of snow will get lost until ground temperatures reach at or below 32F.