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East Coast Rain Blues

Why cold and snow is out and wet a warm remains the theme in the East, join in the conversation.

Phased Vort

January 12-14, 2019 | Winter Storm

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11 minutes ago, risingriver said:

 

That zero line isn't the same thing as the 540 line is it? If so, that's as far north as I have seen it on any model, but I am thinking it is some other weather geek thing I am not enough of a nerd yet to know about. Enlighten me please?

540 line is the height from the surface  (1000mb) to 500mb.   Its a useful indicator of rain/snow, but its possible to have rain with a 534 thickness and snow with a 546 thickness.  It can be affected by different layers having different temps.   

The 0 line at 850mb (5,000 feet) is the actual temperature at that layer. If its over 0c, snow is highly unlikely as it melts in that layer.  However, it can still sleet or be freezing rain if the layers under it are below freezing.   You can also have sleet if its warmer above 850.

http://www.theweatherprediction.com/winterwx/thicknesscriteria/

Ohh page topper

What the the tree say after the long winter?  What a re-leaf!

 

Edited by StretchCT
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1 minute ago, so_whats_happening said:

the 540 line represents the thickness of the atmosphere above a given location. It is the height at which the 500mb level exists (5400m above the surface) as a 546 line would represent the height is now up to 5460m above the surface. They tend to use the 540 line a rudimentary rain/snow line not always the case changes from time to time and season to season. That 0 line is the true representation though of the freezing line at that given height so at 850mb (~5,000ft AGL) the freezing line cuts into southern VA hence the issue of FZR and sleet down that way. Hope that helps. And finally they fixed the comp at work so I should be able to post those sections next week when im back in.

Wouldn't the rates over come any boundary layer issues relative to precip type though? So most of SOVA probably stays more white than just going strictly by temp profile? 

Yes, the column does cross to nonfreezing, but look how quickly it dives back - glomming flakes?

skewt.thumb.PNG.e08a0947fe51c66f6d930a65e862aab2.PNG

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1 minute ago, UTSwiinii said:

Wouldn't the rates over come any boundary layer issues relative to precip type though? So most of SOVA probably stays more white than just going strictly by temp profile? 

Yes, the column does cross to nonfreezing, but look how quickly it dives back - glomming flakes?

skewt.thumb.PNG.e08a0947fe51c66f6d930a65e862aab2.PNG

Meh - maybe not, the rates are not that great in the DGZ:352nmsp:

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1 minute ago, UTSwiinii said:

Wouldn't the rates over come any boundary layer issues relative to precip type though? So most of SOVA probably stays more white than just going strictly by temp profile? 

Yes, the column does cross to nonfreezing, but look how quickly it dives back - glomming flakes?

skewt.thumb.PNG.e08a0947fe51c66f6d930a65e862aab2.PNG

Ohhhh thats quite the warm push to me sounds like a lot of pinging action there strong lift yes does help but say those temps were closer to 35-36 instead of pushing close to 40 there might be a different story. Would argue a heavy wet snow with that.

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33 minutes ago, UTSwiinii said:

Renken's getting it but good right now, in COMO. Maybe he can give us an upstream report? 

 

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2 minutes ago, UTSwiinii said:

Wouldn't the rates over come any boundary layer issues relative to precip type though? So most of SOVA probably stays more white than just going strictly by temp profile? 

Yes, the column does cross to nonfreezing, but look how quickly it dives back - glomming flakes?

skewt.thumb.PNG.e08a0947fe51c66f6d930a65e862aab2.PNG

Good example of what I was talking about when its over 0c higher than 850mb.  I've definitely seen it sleet under this condition.  Just that 1500 feet or so can do some damage. 

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7 minutes ago, StretchCT said:

540 line is the height from the surface  (1000mb) to 500mb.   Its a useful indicator of rain/snow, but its possible to have rain with a 534 thickness and snow with a 546 thickness.  It can be affected by different layers having different temps.   

The 0 line at 850mb (5,000 feet) is the actual temperature at that layer. If its over 0c, snow is highly unlikely as it melts in that layer.  However, it can still sleet or be freezing rain if the layers under it are below freezing.   You can also have sleet if its warmer above 850.

http://www.theweatherprediction.com/winterwx/thicknesscriteria/

Ohh page topper

What the the tree say after the long winter?  What a re-leaf!

 

Yes and those thicknesses are based on average so even the thinest of warm layers in there will skew the idea of it being the rain/snow line. Of course fronto forcing and lift combo do play a role in what many see as well. Have had thicknesses below 540 many times around here to get tons of sleet but on the flip as you stated have had snows above 540.

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Sitting near confluence of Chesapeake and Potomac in my storm fort on the porch. Warnings are up numbers are increasing. Updates to follow.

0111191630a.jpg

Edited by SOMD Tony
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GFS precip trend

gfs_apcpn_eus_fh66_trend.thumb.gif.9d7d6d99ff515c727027c41dbfa552d9.gif

and snow

image.thumb.png.c39d53947cf668639ff51956af0e85db.png

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sref for sby doubled from 9am to 3pm. As I said earlier it does appear that last minute models are playing catch up with snow totals in the Midwest so interesting to see if that translate to the mid-atlantic as well. I know this isn't a storm for everyone but for here on the shore it could be a fairly significant storm. I fly back from Charleston tomm should be interesting to track.

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1 minute ago, Keith3565 said:

sref for sby doubled from 9am to 3pm. As I said earlier it does appear that last minute models are playing catch up with snow totals in the Midwest so interesting to see if that translate to the mid-atlantic as well. I know this isn't a storm for everyone but for here on the shore it could be a fairly significant storm. I fly back from Charleston tomm should be interesting to track.

They never model QPF right so thats probably what we are seeing happen track seems pretty set in stone at this point. I was always told never trust QPF outside of 24 hours. come to think of it there were quite a few things my professors told me about models to never trust. lol

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Wow really fell off in here...Looking forward to this in DC tomorrow night!

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1 minute ago, konka said:

Wow really fell off in here...Looking forward to this in DC tomorrow night!

Yea no snow north of philly forget about others chatting in here lol

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The models have been consistently showing a dry'ish slot running west to east in Loudoun county through DC and to the Bay. It's been rather consistent and it wouldn't be the first time I see a lack of moisture making it to us in systems like this. We'll see if the models picked that out as well. I certainly hope not. 

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1 minute ago, jgentworth said:

The models have been consistently showing a dry'ish slot running west to east in Loudoun county through DC and to the Bay. It's been rather consistent and it wouldn't be the first time I see a lack of moisture making it to us in systems like this. We'll see if the models picked that out as well. I certainly hope not. 

Seems like frontogenesis issue. Where you have extreme upward motion the other side will feature quite the opposite just gotta watch the area that occurs.This could be the reason DC doesnt get nearly as much but will have to see how it evolves. Then you get another fronto forcing region further up in the atmosphere (700mb) which would go north of that region which would be bmore to southern pa area. 

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12 minutes ago, jgentworth said:

The models have been consistently showing a dry'ish slot running west to east in Loudoun county through DC and to the Bay. It's been rather consistent and it wouldn't be the first time I see a lack of moisture making it to us in systems like this. We'll see if the models picked that out as well. I certainly hope not. 

 

On the globals sure, but that hasn't appeared on the NAM recently.

 

807EznM.gif

Edited by konka

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1 hour ago, Keith3565 said:

sref for sby doubled from 9am to 3pm. As I said earlier it does appear that last minute models are playing catch up with snow totals in the Midwest so interesting to see if that translate to the mid-atlantic as well. I know this isn't a storm for everyone but for here on the shore it could be a fairly significant storm. I fly back from Charleston tomm should be interesting to track.

Good luck down there Keith! I said yesterday, always a battle for the delmarva. Hope you cash in! 

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21 minutes ago, so_whats_happening said:

Seems like frontogenesis issue. Where you have extreme upward motion the other side will feature quite the opposite just gotta watch the area that occurs.This could be the reason DC doesnt get nearly as much but will have to see how it evolves. Then you get another fronto forcing region further up in the atmosphere (700mb) which would go north of that region which would be bmore to southern pa area. 

radar.thumb.PNG.7776b98412ec52eb6938a494d6da8aa7.PNG

SPC.thumb.PNG.9aae5914d997a63b0eb28fe2079d504b.PNG

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4 hours ago, Miller A said:

Off topic, whatever, but this FOX just right now LITERALLY ran across my window sill here at work.  Odd landscaping that has dirt/mulch up to the sill with some kind of evergreeny type bushes along it. So, it ran across the sill and by the time I got my camera it was crossing the street.  It was in poor health.  I am wondering if it was actually El Chupacabra.  Hope it finds something to eat soon

Aside from that, It's so sunny out that you would never know that is NOt going to snow tomorrow.  Sigh

image.png.3178df52f9744598d4c840cfc9c41331.png

You sure that's not a coyote?  Doesn't look like a fox to me - the tail is way too long.  Coyotes are very active right now; it's their mating season.

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updated Sterling Digital forecast. 

Screen Shot 2019-01-11 at 7.07.51 PM.png

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36 minutes ago, so_whats_happening said:

Yea no snow north of philly forget about others chatting in here lol

More like - bigger steak on their menu I'll bet.  :classic_wink:

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3 minutes ago, UTSwiinii said:

radar.thumb.PNG.7776b98412ec52eb6938a494d6da8aa7.PNG

SPC.thumb.PNG.9aae5914d997a63b0eb28fe2079d504b.PNG

Great example of that taking place around kansas city right now.

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3 hours ago, so_whats_happening said:

Will say that will be one tight gradient in SE PA. Im going up to allentown tomorrow and feel they may not even see a flake but when i go home that should be a fun commute.

What probably gives a boost up this way is the 700mb fronto forcing comes into Southern PA which will help enhance and yea 15:1 seems to be a good call on the northern side maybe down to 12:1 in bmore and DC areas. By far the heaviest QPF/ snow area should be between richmond and DC some strong 850 fronto forcing there.

Easy dog, we A-towners don't take kindly to outsiders, especially when you yuck it up and say we might not get a flake and your ride back might be rough. It might get rough before you get outta here boy !

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