December Medium/Long Range Discussion

[osfan24]

Mixing is obviously always a concern, and I'll be interested to see how my move from Southeast Elkridge to the far western portion of Ellicott City makes an impact. However, I didn't mix even in my old location in December 2009, the two February 2010 storms or the January 2016 storm. I mixed back in 2003 in College Park, and 1996 in the Baltimore area. Obviously, December mixing is more of a concern than later in the winter given climo, but I won't start getting concerned until Monday if the mixing is still showing up. We just don't get many storms around here, especially coastals, where we get around a foot or so of snow. Certainly nothing in recent memory that I can remember. It's either a mauling of around two feet, give or take, or not much. I guess February 2014 and January 2011 could fit the bill sorta/kinda.

[snowmagnet]

I know it's still early in the season and I am less than a weather amateur, but I know we have had several significant snowstorms just a couple of days after having 60's and 70's.  

[EastCoast NPZ]

5 minutes ago, 40westwx said:

Hold on.. didnt it snow like a foot in Denver earlier this year on the same day it was 80 degrees?

Yes, but their soil is 5,000 ft further from the Earth's core, so it's cooler.

[Maestrobjwa]

1 minute ago, snowmagnet said:

I know it's still early in the season and I am less than a weather amateur, but I know we have had several significant snowstorms just a couple of days after having 60's and 70's.  

Yeah he was being mostly sarcastic with that comment...lol

[Fozz]

2 minutes ago, osfan24 said:

Mixing is obviously always a concern, and I'll be interested to see how my move from Southeast Elkridge to the far western portion of Ellicott City makes an impact. However, I didn't mix even in my old location in December 2009, the two February 2010 storms or the January 2016 storm. I mixed back in 2003 in College Park, and 1996 in the Baltimore area. Obviously, December mixing is more of a concern than later in the winter given climo, but I won't start getting concerned until Monday if the mixing is still showing up. We just don't get many storms around here, especially coastals, where we get around a foot or so of snow. Certainly nothing in recent memory that I can remember. It's either a mauling of around two feet, give or take, or not much. I guess February 2014 and January 2011 could fit the bill sorta/kinda.

The second blizzard in February 2010 had a lot of mixing, especially early on before that amazing redevelopment.

[LP08]

This is the “worst” panel on the gfs for close in dc area.  As long as the rates hang on, it should stay frozen.  I could see a scenario where the precip type changes back and forth depending on the rates.

[WinterWxLuvr]

6 minutes ago, JakkelWx said:

Seriously?

Yes. If you think ground temps don’t matter than I don’t know what to say. As warm as it s now, it will take half the storm to just get the ground cold enough for the snow to stick.

[WxUSAF]

7 minutes ago, JakkelWx said:

Seriously?

100%

[H2O]

11 minutes ago, 40westwx said:

Hold on.. didnt it snow like a foot in Denver earlier this year on the same day it was 80 degrees?

 

10 minutes ago, WxUSAF said:

Totally different on the front range dude.

Snow falls differently out there as well. It doesn’t fall straight down. The angle of the snow can counteract warmth

[WxUSAF]

8 minutes ago, osfan24 said:

Mixing is obviously always a concern, and I'll be interested to see how my move from Southeast Elkridge to the far western portion of Ellicott City makes an impact. However, I didn't mix even in my old location in December 2009, the two February 2010 storms or the January 2016 storm. I mixed back in 2003 in College Park, and 1996 in the Baltimore area. Obviously, December mixing is more of a concern than later in the winter given climo, but I won't start getting concerned until Monday if the mixing is still showing up. We just don't get many storms around here, especially coastals, where we get around a foot or so of snow. Certainly nothing in recent memory that I can remember. It's either a mauling of around two feet, give or take, or not much. I guess February 2014 and January 2011 could fit the bill sorta/kinda.

Going to be a noticeable difference almost certainly unless the ggem scores a coup here. 

[PhineasC]

Seems like the vast majority of the time, rates are the real make-or-break thing around here in marginal events. Temps fall in line when you have rates. Even the mighty I-81 corridor could fall prey to crappy rates that don't accumulate well while some place much further SE gets into intense banding and gets a paste job at 33-34 degrees. I wouldn't be paying much attention to snow maps or small temp variations, just where the heaviest precip sets up. It feels like a lot of these supposedly heavy precip events end up spitting for long periods of time which really messes up snow totals.

[olafminesaw]

3 minutes ago, WinterWxLuvr said:

Yes. If you think ground temps don’t matter than I don’t know what to say. As warm as it s now, it will take half the storm to just get the ground cold enough for the snow to stick.

Right up there with radar attenuation...

[09-10 analogy]

1 hour ago, H2O said:

It safe to say most of us I-95 and east people have seen and been through this enough to know what will happen.  Models will draw us in with snow maps and precip depictions saying we should be frozen. But there will be that one layer at 850/925 that will have +1 or +2C and it will punch in as far as DC and the fall line. Only those with elev and rates will be ok.  For those under 300’ we fight that warm layer every. Single. Time. 

I fight it even around 400' inside the Beltway. Last decent snow in Jan 19, DC more or less jackpotted, which Just Doesn't Happen. So on that basis alone, I am fully expecting a sloppy few inches while the Catoctins and the north Jersey shore do their usual epic nukage dance. It's the way our little corner of the snowiverse works.  

The solution would be to displace Sugarloaf Mountain 35 miles or so to the SE, but that might create other problems. Or, thinking real big, get rid of the Bay, Alleghenies, and Blue Ridge, and move DC 100 or so miles upriver. We'd probably still average under 20" a year. 

[SomeguyfromTakomaPark]

1 minute ago, WxWatcher007 said:

Antecedent cold isn’t a concern in this event outside of the usual SE spots imo. Here’s the 00z EPS high temperature 50th percentile chart.

Forget about the verbatim numbers for a second and look at the wedge of cold nestled all the way into upstate South Carolina. That’s a very strong CAD signal.

Again, this is the ensemble so it’s not a random drawing like an op run can be. The cold is in place in most locations as the storm is arriving. Now that doesn’t mean mixing won’t happen or that things can’t trend warmer at the surface or aloft, but that’s a great signal right there.

Good post.  You love to see a map like this for the day of a storm.  Nothing worse than being 45 degrees when the precip starts and waiting for cold. 

[LeesburgWx]

Who has the Mid Atlantic Bingo card handy? Time to check off ground temps will be an issue

[PhineasC]

1 minute ago, WxWatcher007 said:

Antecedent cold isn’t a concern in this event outside of the usual SE spots imo. Here’s the 00z EPS high temperature 50th percentile chart.

Forget about the verbatim numbers for a second and look at the wedge of cold nestled all the way into upstate South Carolina. That’s a very strong CAD signal.

Again, this is the ensemble so it’s not a random drawing like an op run can be. The cold is in place in most locations as the storm is arriving. Now that doesn’t mean mixing won’t happen or that things can’t trend warmer at the surface or aloft, but that’s a great signal right there.

Yep, there is some cold to tap which is why I think those who get into super-heavy rates as the storm wraps up will be fine for a paste-job at least, even if temps look marginal. Anyone sitting under marginal rates will have crappy accumulation even if they have better temps. Which is why no one should be spiking any footballs yet. I am serious when I say there are still some SE and OTS-looking runs coming, probably Monday. It always happens before they correct back to a final position.

[40westwx]

13 minutes ago, WxWatcher007 said:

Antecedent cold isn’t a concern in this event outside of the usual SE spots imo. Here’s the 00z EPS high temperature 50th percentile chart.

Forget about the verbatim numbers for a second and look at the wedge of cold nestled all the way into upstate South Carolina. That’s a very strong CAD signal.

Again, this is the ensemble so it’s not a random drawing like an op run can be. The cold is in place in most locations as the storm is arriving. Now that doesn’t mean mixing won’t happen or that things can’t trend warmer at the surface or aloft, but that’s a great signal right there.

The source of the cold air is significant also.. Wednesday morning might be the coldest day of the year for many in the NE. It might be in the low 20s for @psuhoffman when its starts snowing.

[poolz1]

Time to start extrapolating....

[LP08]

ICON much colder for Wed 

[Buddy1987]

3 minutes ago, poolz1 said:

Time to start extrapolating....

High 2mb deeper. That’s a plus. H5 looks ready to explode.

[Kevin Reilly]

1 hour ago, WxWatcher007 said:

December 23rd 2009 we got 23” here in Southeastern PA and the ocean water temperature at Atlantic City was 53. All about the proximity to the coast for the storm and that all important NE to NNE wind vector along the I-95 corridor happens all the time.  

[Herb@MAWS]

27 minutes ago, osfan24 said:

Mixing is obviously always a concern, and I'll be interested to see how my move from Southeast Elkridge to the far western portion of Ellicott City makes an impact. However, I didn't mix even in my old location in December 2009, the two February 2010 storms or the January 2016 storm. I mixed back in 2003 in College Park, and 1996 in the Baltimore area. Obviously, December mixing is more of a concern than later in the winter given climo, but I won't start getting concerned until Monday if the mixing is still showing up. We just don't get many storms around here, especially coastals, where we get around a foot or so of snow. Certainly nothing in recent memory that I can remember. It's either a mauling of around two feet, give or take, or not much. I guess February 2014 and January 2011 could fit the bill sorta/kinda.

Definitely advantageous to be even 15-20 miles west of the SE side of Elkkridge.  Yesterday BWI was 58 while IMBY it was just under 51, about 15mi west of BWI.  Noticed similar temp disparity the day before.  Of course, it's usually less exaggerated when overcast and precip'ing.

 

[nj2va]

1 minute ago, LP08 said:

ICON much colder for Wed 

Monday’s storm really blows up in the 50/50 region.

[Buddy1987]

2 minutes ago, LP08 said:

ICON much colder for Wed 

Good shift in confluence and pushed to the south southwest at75.

[LP08]

Just now, nj2va said:

Monday’s storm really blows up in the 50/50 region.

Yup. Added a better push from the confluence.  Still not as good as the other “better” models but it was a good step.

[LeesburgWx]

The ICON had nowhere to go but colder

[PhineasC]

ICON thermals are pretty useless. It had a lot of rain for that last coastal even way up in Northern NH.

[LP08]

Just for posterity.  Has been considerably less in prior runs.

[SnowGoose69]

6 minutes ago, LP08 said:

ICON much colder for Wed 

Its because it has a "bomb" for Monday in relative terms.  Its like low 990s off NJ Monday

[RDM]

18 minutes ago, DCTeacherman said:

Good post.  You love to see a map like this for the day of a storm.  Nothing worse than being 45 degrees when the precip starts and waiting for cold. 

Notice the teens in upstate NY with purples in Quebec.  That's some really cold stuff there and strong flow pumping it southward.