Dec. 4-5 SE Rain/Snow Storm, Reality: Short Range [0-3 Days Out] Forecasts Options

[1234snow]

I figured since there wasn't a thread for the clipper coming through this weekend that I'd make one. This looks to be a light snow event for folks in Tennessee and the Mountains, but it will probably start out as rain in most of the lower elevations.

Been taking some quick glances at the GFS and the NAM and there are some pronounced differences between the two models and here is a comparsion from the 18z NAM and GFS:

18z NAM:





18z GFS:





The GFS has a colder solution but there isn't as much precip and the NAM shows a strong clipper system with alot of precip, but it draws more warm air into it. Either way it should start as rain in the lower elevations and then change to snow and the mountains would probably stay snow the entire event.

This is just for the clipper coming through during the weekend and not for the potential southern stream system after that.

[vann]

Im not sure about this as my memory goes BLANK sometimes. Now where was I?? Seems like we had a few of these clippers last year. We got some decent little snows, John 1122 got some really good snows over his way. I hope we get some of this headed our way here in Monterey, TN this weekend. The cold is definitely here right now!!

This post has been edited by vann: Dec 1 2010, 10:08 PM

[chattownsnow]

All the attention has been focused on the possible storm from 7th-9th. I have been watching the models and they have been trending south with this storm lately, which would bring a lot of North Carolina, southern VA, and Tennessee in the chances for snow. Who knows this one may suprise someone.

[1234snow]

Im not sure about this as my memory goes BLANK sometimes. Now where was I?? Seems like we had a few of these clippers last year. We got some decent little snows, John 1122 got some really good snows over his way. I hope we get some of this headed our way here in Monterey, TN this weekend. The cold is definitely here right now!!

John always got more snow. Just kidding John, you deserved that good winter last year after the countless years of the "bubble" over your house.

0z NAM took the low over Tennessee and through the mountains on this run:

Hour 66:



Hour 72:



Hour 78:



Edit: changed "threw" to "through"

This post has been edited by 1234snow: Dec 1 2010, 10:27 PM

[John1122]

I did make out pretty well last year, and sometimes I do okay with this type of clipper. Ultimately depends on it's path, but the last two first Saturdays in December in a row have had a clipper system that gave me accumulating snow. Hope this is the trifecta.

[vann]

Yes, I just checked out the NAM and Looked at the same time period on the GFS and it could vey well be a nicely gift wrapped surprise for some in the neck of our woods, and beyond!!! John had to wear snow shoes alot of the time last year. Me too, until the wife said I was tracking to much grass in. That's what happens when you have no snow. In the wise words of YODA ," hmmmm.. Not any snow this year you have! Hmmmmm..

This post has been edited by vann: Dec 1 2010, 10:43 PM

[John1122]

Im not sure about this as my memory goes BLANK sometimes. Now where was I?? Seems like we had a few of these clippers last year. We got some decent little snows, John 1122 got some really good snows over his way. I hope we get some of this headed our way here in Monterey, TN this weekend. The cold is definitely here right now!!

Vann, if this sets up like Jackson KY NWS is thinking it might be a similar situation to Valentine's Day weekend earlier this year were the Plateau got quite a bit of upslope snow shower activity. Seems like you managed about 8 inches out of that didn't you?

I doubt this would be anything close to that, looks like the fetch will be more condusive for SE KY/SW VA mountains and the Smokies right now. Plus it's a bit warmer with this set up as well.

I wouldn't be surprised to get an inch or so by the time this clipper is over, depending on time of day it gets here.

JKL says that top down cooling will occur and seem very sure that anything that falls in their CWA will be snow on both Saturday and Sunday.

Morristown NWS is much warmer and doesn't seem to have much to say regarding any evap cooling.

[John1122]

Yes, I just checked out the NAM and Looked at the same time period on the GFS and it could vey well be a nicely gift wrapped surprise for some in the neck of our woods, and beyond!!! John had to wear snow shoes alot of the time last year. Me too, until the wife said I was tracking to much grass in. That's what happens when you have no snow. In the wise words of YODA ," hmmmm.. Not any snow this year you have! Hmmmmm..

Last year two things happened that I never recall happening before. We had the December 18th snow where Campbell County got buried but every direction from here saw rain/snow mix thus almost no accumulation. I don't recall ever getting a snow event here and Scott and Claiborne Co getting rain/snow like that.

Then the Jan 29th and 30th system were even you guys on the Central Plateau switched to freezing rain and sleet. I don't really recall Crossville and that area switching like that while we stayed all snow before.

Usually we have almost exactly the same weather as Crossville except we get a little bit more NW flow snow because we are closer to the typical trajectory from Lake Michigan.

[1234snow]

Vann, if this sets up like Jackson KY NWS is thinking it might be a similar situation to Valentine's Day weekend earlier this year were the Plateau got quite a bit of upslope snow shower activity. Seems like you managed about 8 inches out of that didn't you?

I doubt this would be anything close to that, looks like the fetch will be more condusive for SE KY/SW VA mountains and the Smokies right now. Plus it's a bit warmer with this set up as well.

I wouldn't be surprised to get an inch or so by the time this clipper is over, depending on time of day it gets here.

JKL says that top down cooling will occur and seem very sure that anything that falls in their CWA will be snow on both Saturday and Sunday.

Morristown NWS is much warmer and doesn't seem to have much to say regarding any evap cooling.

I wished the mets at Jackson and Morristown could switch. Jackson gives in depth discussions about systems and it could be a raging blizzard and Morristown could sum it up in less than a paragraph it seems.

[athensga]

Looks like some flurries are possible over the Apps and some other areas. Looks like the main thing from this clipper system is, COLD .
Hour 72
0z GFS
Hour 96
0z GFS

[nc3912]

Anyone have the snowfall map for the 0Z 84 hour NAM? Thanks.

[1234snow]

Anyone have the snowfall map for the 0Z 84 hour NAM? Thanks.

http://raleighwx.americanwx.com/models/nam...msnow_SE084.gif

[vann]

Vann, if this sets up like Jackson KY NWS is thinking it might be a similar situation to Valentine's Day weekend earlier this year were the Plateau got quite a bit of upslope snow shower activity. Seems like you managed about 8 inches out of that didn't you?

I doubt this would be anything close to that, looks like the fetch will be more condusive for SE KY/SW VA mountains and the Smokies right now. Plus it's a bit warmer with this set up as well.

I wouldn't be surprised to get an inch or so by the time this clipper is over, depending on time of day it gets here.

JKL says that top down cooling will occur and seem very sure that anything that falls in their CWA will be snow on both Saturday and Sunday.

Morristown NWS is much warmer and doesn't seem to have much to say regarding any evap cooling.

John, yes I remember. Feb 14th we ended up with around 2 inches or so H 34-L 18, Dec 18th we ended up with 1.24 inches of precip (rain Freezing rain some?) H 42-L33.

Then on Jan 24th we received 2.15 of precip (rain) while 5-6 days later we welcomed atleast 10 inches snow. 29th H 30-L 25, 30th H31- L18.

Didn't we have a WSW out for the one on 18th and it was just rain.

[hckyplayer8]

Keep in mind these clippers are moisture starved and the farther the clipper dives South, the more time it has spent overland.

[1234snow]

Keep in mind these clippers are moisture starved and the farther the clipper dives South, the more time it has spent overland.

Yeah, to be honest I think the NAM is overdoing the precip by a good bit and the GFS seems more reasonable precip wise.

[John1122]

Morristown jacked up their snow chances for this period now, said they may have to raise amounts too.

I now have a 20% chance of snow Friday night, 50% chance of snow before 1 on Saturday, changing back to snow Saturday night with snow likely.

Their morning disco says that the odds are getting better that more snow may fall, that it may be colder and their current snow forecast may be underdone.

This post has been edited by John1122: Dec 2 2010, 07:31 AM

[Removed_Member_Garrett_*]

There is currently a 40% chance of either flurries or snow showers here Saturday Night. This would be for my town, Courtland, VA.

[calculus1]

The 06Z NAM is not as bullish on the precipitation making it over the mountains into NC and SC, but it does indicate a little light precip for eastern and central TN. There's a huge dry slot in the lee of the Appalachians in NC (like normal with these clipper systems). Having lived in the shadow of these mountains for 25+ years, I've learned not to expect much if anything from these clipper systems. Sometimes they completely skip over the foothills and western piedmont of NC, but then reinvigorate once they get to the Research Triangle area and points further east.

Hour 66:


Hour 72:


Hour 78:


Hour 84:


This post has been edited by calculus1: Dec 2 2010, 09:55 AM

[calculus1]

I just noticed the 12Z NAM has already come out, and it seems to have reversed course on the dry slot:

Hour 66:


This would be interesting if it verified, but I still think it would be quite unusual as well. I'd like to compare the 12Z GFS to this and see what we have then.

This post has been edited by calculus1: Dec 2 2010, 09:55 AM

[weatherguysc]

Here's the GFS 12z at hour 66 for comparison to the NAM. The GFS is showing a pretty good sized dry slot still.

GFS Hour 66