Feb. 18-20, 2012 Disco/Analysis

[NCSNOW]

That map from DT says alot about MBY situation. Can't count the repeating times we go through this here. Literally would get 2+ inches if this verifies. However no more than a 30-40 mile swing North or South, I would get zilch or 7-8 inches. Got a full tank in the 4x4, so you can bet I'll see the white stuff one way or the other.

[burgertime]

Did anyone post the 18z GEM? It has a good amount of precip still in NC @36 hours...hard to read but would be between .10 and .20 in MBY of QPF

[rduwx]

I think folks are being very conservative with the accumulation forecasts. I don't see how Wake and Durham counties could get just a trace to an inch when the models have all been trending for more and more as the day has gone alone.

I think you're setting your self up for a disappointment. If for some reason we end up w/ more that would be great but I believe you have to go into this storm thinking maybe an inch. Of course there are the possibilities where we could end up w/ more. If the deformation band goes through our area is one possibility but it's hard to predict where that band is going to set up at.

[Cold Rain]

These are the kinds of storms that will lull you into believing you have a chance at a nice surprise and have you watching ever shift of every model and in the end you get nothing. Be careful.

[burgertime]

These are the kinds of storms that will lull you into believing you have a chance at a nice surprise and have you watching ever shift of every model and in the end you get nothing. Be careful.

I've learned this hard lesson over the past two years. It almost never is a "surprise" in my favor almost always the opposite.

[strongwxnc]

This is the why you should approach all storms! Good post...

These are the kinds of storms that will lull you into believing you have a chance at a nice surprise and have you watching ever shift of every model and in the end you get nothing. Be careful.

[nchighcountrywx]

Even in the mountains, we have the concern with this one.

@wxbrad: It could snow for hours & accumulations will be hard to come by with these soil temperatures. http://twitpic.com/8lp33r #snOMG

[strongwxnc]

Posted on Andy Wood's Facebook page

http://www.facebook.com/#!/awood11

"The warm ground temperature argument is drastically overplayed during the winter, especially when heavy precipitation and snowfall rates are likely. Heavy and consistent snow rates trump the entire "soil is too warm" argument. I have seen numerous times (in TN, MS, GA and SC) where 50-degree soil temperatures and (60-degree air the day before) was overcome in the first 30 minutes by consistent moderate-heavy snow. The key is a consistent rate of snow. If inconsistent and only moderate snow at times, warm ground temps will overwhelm snow rates. This is an intense, dynamic system capable of manufacture it's own cold air as precipitation rates dictate how much cold is pulled from the upper-levels."

Even in the mountains, we have the concern with this one.

@wxbrad: It could snow for hours & accumulations will be hard to come by with these soil temperatures. http://twitpic.com/8lp33r #snOMG

[Blue_Ridge_Escarpment]

Posted on Andy Wood's Facebook page

http://www.facebook.com/#!/awood11

"The warm ground temperature argument is drastically overplayed during the winter, especially when heavy precipitation and snowfall rates are likely. Heavy and consistent snow rates trump the entire "soil is too warm" argument. I have seen numerous times (in TN, MS, GA and SC) where 50-degree soil temperatures and (60-degree air the day before) was overcome in the first 30 minutes by consistent moderate-heavy snow. The key is a consistent rate of snow. If inconsistent and only moderate snow at times, warm ground temps will overwhelm snow rates. This is an intense, dynamic system capable of manufacture it's own cold air as precipitation rates dictate how much cold is pulled from the upper-levels."

Excellent write-up on this. Most important part is in bold. I've been a witness to 60 degree days as well and everyone saying, there's no way its going to snow and stick, but the next day several inches was on the grass and even the roads. All dependent on the rate of the snow!

[valkhorn]

Posted on Andy Wood's Facebook page

http://www.facebook.com/#!/awood11

"The warm ground temperature argument is drastically overplayed during the winter, especially when heavy precipitation and snowfall rates are likely. Heavy and consistent snow rates trump the entire "soil is too warm" argument. I have seen numerous times (in TN, MS, GA and SC) where 50-degree soil temperatures and (60-degree air the day before) was overcome in the first 30 minutes by consistent moderate-heavy snow. The key is a consistent rate of snow. If inconsistent and only moderate snow at times, warm ground temps will overwhelm snow rates. This is an intense, dynamic system capable of manufacture it's own cold air as precipitation rates dictate how much cold is pulled from the upper-levels."

I wonder what the soil temps were before March 1993 or April 1987. They couldn't have been cold.

I also remember growing up in MS when in Feb. 1996 (after a warm spell) we got an ice/snow storm and frigid temps and in spite of what I thought were warm soil temps everything that fell stuck around all weekend.

[Met1985]

Posted on Andy Wood's Facebook page

http://www.facebook.com/#!/awood11

"The warm ground temperature argument is drastically overplayed during the winter, especially when heavy precipitation and snowfall rates are likely. Heavy and consistent snow rates trump the entire "soil is too warm" argument. I have seen numerous times (in TN, MS, GA and SC) where 50-degree soil temperatures and (60-degree air the day before) was overcome in the first 30 minutes by consistent moderate-heavy snow. The key is a consistent rate of snow. If inconsistent and only moderate snow at times, warm ground temps will overwhelm snow rates. This is an intense, dynamic system capable of manufacture it's own cold air as precipitation rates dictate how much cold is pulled from the upper-levels."

Great write up. I have see it in the 70s one day and 3-4 inches of snow the next day.

[Poimen]

not to belabor the point about soil temps, but I wonder what the soil temps were in PA on the eve of the Hallowwen storm this past October? Fact is if it snows hard enough and long enough snow will stick to grassy surfaces just fine.

[superjames1992]

These are the kinds of storms that will lull you into believing you have a chance at a nice surprise and have you watching ever shift of every model and in the end you get nothing. Be careful.

You got that right! I'm not really expecting anything more than an inch here. I think more may fall, but not accumulate. I realize the potential for a surprise and love when the Euro and NAM dump 4-6" on my area, but I don't believe it's realistic to expect that to actually happen.

Posted on Andy Wood's Facebook page

http://www.facebook.com/#!/awood11

"The warm ground temperature argument is drastically overplayed during the winter, especially when heavy precipitation and snowfall rates are likely. Heavy and consistent snow rates trump the entire "soil is too warm" argument. I have seen numerous times (in TN, MS, GA and SC) where 50-degree soil temperatures and (60-degree air the day before) was overcome in the first 30 minutes by consistent moderate-heavy snow. The key is a consistent rate of snow. If inconsistent and only moderate snow at times, warm ground temps will overwhelm snow rates. This is an intense, dynamic system capable of manufacture it's own cold air as precipitation rates dictate how much cold is pulled from the upper-levels."

not to belabor the point about soil temps, but I wonder what the soil temps were in PA on the eve of the Hallowwen storm this past October? Fact is if it snows hard enough and long enough snow will stick to grassy surfaces just fine.

Right. However, I am not sure how heavy or how consistently the snow will fall during this one. If the snow is light and/or comes in squalls with just light snow/flurries in between, we will have a hard time coming by many accumulations.

[jburns]

Last call from DT. Looks good!

I'm surprised no one else has commented on this so maybe I'm the one seeing it wrong but isn't this map a bit screwed up? On the map he has 2-4" over the NC piedmont and across the VA tidewater in green but in the legend he has green equaling 1-2". Also the tan over far north central NC an through VA above the green he has 1-2" but the legend talks about longer duration snow than the 2-4" inch area.

EDIT: OK after looking further I see the thin lines separating the amounts but still find it strange seeing 8-12" over a color that is described as much less in the legend.

[Isopycnic]

I'm surprised no one else has commented on this so maybe I'm the one seeing it wrong but isn't this map a bit screwed up? On the map he has 2-4" over the NC piedmont and across the VA tidewater in green but in the legend he has green equaling 1-2". Also the tan over far north central NC an through VA above the green he has 1-2" but the legend talks about longer duration snow than the 2-4" inch area.

EDIT: OK after looking further I see the thin lines separating the amounts but still find it strange seeing 8-12" over a color that is described as much less in the legend.

Wxrisk.com

DONT FORGET THE DONATE BUTTON... on the LEFT side of the page UNDER the WXRISK.com LOGO...

[superjames1992]

I'm surprised no one else has commented on this so maybe I'm the one seeing it wrong but isn't this map a bit screwed up? On the map he has 2-4" over the NC piedmont and across the VA tidewater in green but in the legend he has green equaling 1-2". Also the tan over far north central NC an through VA above the green he has 1-2" but the legend talks about longer duration snow than the 2-4" inch area.

EDIT: OK after looking further I see the thin lines separating the amounts but still find it strange seeing 8-12" over a color that is described as much less in the legend.

I think DT's totals are too high, in general. Also, I don't think there will be quite as dramatic of a difference between what Raleigh and the Triad sees. It looks like he's only calling for ~2" in Asheville, too, which seems kind of low, to me.

[POWERSTROKE]

as long as we get moisture we will get ice tomorrow night which will work for me

[Local Yokel Wx]

I think DT's totals are too high, in general. Also, I don't think there will be quite as dramatic of a difference between what Raleigh and the Triad sees. It looks like he's only calling for ~2" in Asheville, too, which seems kind of low, to me.

I dont see Asheville getting 2", maybe a slushy inch downtown with the higher elevations raking in as they are closer to the bulk of the precip. Here in SW NC (Cullowhee) we are on the southern extent of the precip, so we're just rooting for a solid dusting.

But I would love to be told im wrong, so any opinion to my thinking is welcomed.

[burgertime]

Well NAM is rolling right away the southern energy is a tad slower and a bit south. That northern energy looks sharper so we'll see where this run goes.

[rduwx]

The energy dropping down from the northern stream looks strong this run.

[burgertime]

This run is colder @12 compared to 18z..00z has 850's going into the mountains of NC on the 18z it was in Northern VA.

[Wow]

colder, but weaker SLP, less precip due to slower phasing.

[burgertime]

The energy dropping down from the northern stream looks strong this run.

One thing I'm worried about is if it phases....it doesn't look to phase till late still not sure if we want it to phase early or late though so maybe that's a good thing.

[Poimen]

NAM much slower and weaker with the LP.

[burgertime]

colder, but weaker SLP, less precip due to slower phasing.

That's what I was worried about, we want this to phase earlier to get more precip correct?

[SBUWX23]

weaker slp would mean less WA and less of a warm nose with this being further south and RDU profiles have no warm nose at 21z. in fact its isothermal near 0C

[rduwx]

Looks like we have the beginning of a phase at hr 21...Heavy precip in all of NC but 850's aren't there yet.

[burgertime]

weaker slp would mean less WA and less of a warm nose with this being further south and RDU profiles have no warm nose at 21z. in fact its isothermal near 0C

BOOM @24! This is going to be good for someone in Central NC.

[rduwx]

hr 24 looking good...850's are good and heavy precip.

Thanks SBU for the clarification.

[Poimen]