Mixed signals for SW Va on Wed. snow
* The major American forecast models — the North American Model and Global Forecast System — have each shifted the bulk of Wednesday’s snowfall north and east AWAY from Southwest Virginia. Amounts would be light in most areas if these models verify, with the heaviest snow north of Interstate 64.
* The European (ECMWF) and British (UKMET) forecast models, and to a lesser extent the Canadian, maintain a significant threat of heavy snow in our region, including some 10+ inch amounts, especially the Roanoke Valley north and east.
* Noting the wide disparity in forecast model solutions, the Hydrometeorological Prediction Center has put all of Virginia west of Richmond in a moderate risk of 4+ inches on Wednesday, and areas west/northwest of Roanoke in a high risk of 4+ inches and slight risk of 12+ inches.
* Much is contingent on the strength and location of a broad blocking low off the coast of Canada/Northeast U.S. and whether that blocking low can force an upper-level “vort max” far enough south for heavy snow to develop in our region. This accounts for much of the model discrepancy.
* My best shot at probabilities for Roanoke and Blacksburg now: 1 inch+, 70 percent; 4 inches+, 50 percent; 6 inches+, 40 percent; 8 inches+, 30 percent; 12 inches+, 20 percent. Chances will be better northward, and generally less to the south.
* This could truly be an “all or nothing” snowstorm with a large area of big snow totals giving way to small amounts within 30 miles or less.
March 3, 2013 - 5:40 PM
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What would it take to get East TN in the snow zone?
Kevin, When would you think we will have a good solid idea as what to expect? Sometime Monday or will it take until Tues. or longer?
Not a good setup for Knoxville, Rachel. Maybe some backside snow showers.
Good solid idea? I think we’ll know by Thursday what it did on Wednesday.
I think it may be Tuesday before we have a good idea on particulars related to SW Virginia. The actual storm is not much in question now. All the stuff we’re concerned about is really very minor details in the big picture of the atmosphere.
I’ll post this this here again since I didn’t realize we had a new thread.
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18z GFS snow map. DC the bullseye.
http://img33.imageshack.us/img33/6205/e45e359f4c1140c682c0f9d.png
I know I might upset a lot of people on here. This schoolteacher is hoping for a complete miss. Don’t get me wrong, I love snow days but we’ve had enough and this is wreaking havoc on my planning and kids getting an education. C’mon Spring, it’s time to kick winter out of here.
Some time tomorrow Kevin (tomorrow evening might be more appropriate), I would like to see your first thoughts on the temperature profiles for Blacksburg and Roanoke. When they will get below 35 degrees, for instance, on late Tuesday and Wednesday early AM.
DC is not going to be the bullseye. Seriously, when has the GFS ever been right this far out. Watch it change it’s tune tomorrow.
I mentioned today’s polar view late on the previous thread. One other thing it definitely showed …. there is an impressive trough over the entire eastern USA right now. I am very glad that I was not in NE Florida for this weekend instead of late January.
I don’t put trust in the gfs this far out. I say it everytime we have a snow chance that 2 days out before nowcasting something shifts and we get in a panic. Can’t recall who said it on the last thread but I agree let it bust or let’s get a good 8+ where it snows for hours. This quick hit 1-4 will just make everything a mess.
How good are the GFS predictions at this point? Are they better then the Euro? Worse? Which will win?
The gfs is crap more than 48 to 72 hours out.
Euro vs. GFS — Euro scores higher on accuracy studies by far, but doesn’t win every single battle between the 2. GFS has scored well on a couple of smaller events lately.
Trends next 36-48 hours will be more important than the snap shot any particular model shows at any given run.
For the record — 20 percent for 12+ inches is by far the highest percentage I have given for any storm at 3 days range since 2009-10. The upside potential of this storm with just a few tweaks here and there is very high.
I told my better half that there would be models today doing away with the snow forecast. It happens before every major snow.
I love this stuff, but lord people get silly.
And it often happens exactly in this range Micah. That’s why I’m a little hesitant to jump on this GFS/NAM northward shift in snow totals.
I think what’s more likely than moving the bullseye back south would be just expanding the snow accumulation area both more north and south. Big storm, may have bigger precipitation shield on back side than we’re seeing at this range.
Seems like it keeps being colder here in Bburg than forecasted. I’m thinking it is going to be a quick cahnge to snow or just all snow. It’s brutal out there!
I believe thats what a few are hinting at over at accuweather. Yesterday we thought the models would converge today now we’re thinking tomorrow. I did not follow Nemo closely, but didn’t the GFS show a much lower snow total and have the precip further south?
Thought you all might like to see the Washington Post coverage. They have really upped their coverage the last few years with a blog a la Kevin’s
http://www.washingtonpost.com/blogs/capital-weather-gang/post/major-winter-storm-eyes-washington-dc-and-mid-atlantic-for-midweek-snowquester/2013/03/03/da29188e-842e-11e2-98a3-b3db6b9ac586_blog.html?tid=pm_pop
I think from my very limited understanding that the track will be Euro with the coverage being greater than anticipated geographically. I think the Euro is seeing the extension of the southern and eastern coverage while the gifs is seeing the extension of the coverage north. I think this thing is gonna blow up huge.
Is there any possibility this could be like the big snowstorm we had back in December of 2009 with 16+ inches? I heard someone say it could also have blizzard-like conditions, is that true?
Clarify, the track is the Euro as it has been before the hitch south.
6to12 is my prediction
We need a 7 or 11 on this roll for 12 inches!! Come on gfseuroradarsnowpredictionmmodels!
So Kevin, is there still a decent shot for us down here in atkins?
i hope it snows
Is there any possibility this could be like the big snowstorm we have back in December of 2009 with 16+ inches? I heard someone say it could also have blizzard-like conditions, is that true?
There is no doubt now i will be on the low end of any precip. as always….but really i aint giving up til thurs. afternoon..lol
Im moving to alaska…
Call for Forecasts!
14th Annual NEWx Snowfall Forecast Contest – Storm #5
Deadline for entries: 10:30 PM EST MON…04-MAR-13
Enter your forecast @ http://www.newx-forecasts.com/
Details @
http://newxsfc.blogspot.com/2013/03/winter-12-13-storm-5-call-for-forecasts.html
I’m glad to see the HPC has the 12″ potential along the I-81 corridor; however, the temps are very concerning. Also, seems we are going to waste alot of precip as rain on Tuesday, and then Weds it gets up to 34 in Blacksburg and 37 in Roanoke. Seems like this is going to be alot of snow, but not much real accumulation. KM-how long do you see accumulating snow lasting? Is this another quick hitter (12 hours or less)?
Anna- I mentioned the blizzard like conditions earlier meaning snow or blowing snow reducing visibility to 1/4 mile or less with 35mph frequent gusts or strong winds. If the euro is king once again places like Bent Mountain will see blizzard conditions or very close to it.
6z and 18z are more often outliers anyway! I’m ready for snow. I got two shovels and a bottle of wild turkey and 5 packages of bacon.
Thanks for the work, Kevin. This is a great resource and one that I really appreciate!
Anna in Roanoke,
There are supposed to be winds gusting up to 50mph. So yes, if this all pans out, we will see some blizzard like conditions.
whatever we get we can not control. check out the grocery stores again on tues evening. the worst part will be the rain prior to the snow. wish it wold be a dry snow. easier to manuver around in for sure.
Getting at that point I may not be able to answer all questions because of volume. But I’ll take a crack at a few recent ones:
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16+ inches would be the top end of possible expectations. Even if we get that much moisture in the form of snow, snow-liquid ratios will likely be less than the typical 10:1 and the snow will compact a lot upon falling. That’s because it will be barely cold enough to snow.
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Snowfall could be 12 hours plus if the higher end snow storm materializes and we are under the “comma head” for that time.
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Doubt we get to the point of blizzard warnings being issued, but some blowing snow issues could develop
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Matt Blacksburg; Capital Weather Gang has been around for several years. And we have a Weather Journal alum on there — Kathryn Prociv, a VT grad who filled in for me about 10 days last fall.
David in Salem: Possible you are right that the precipitation shield ends up being much larger than any model currently shows. May not be a matter of shifting north and south, but expanding some in all directions. Time will tell.
Just got a heavy dusting in Pembroke, enough to make the road white. I stepped out to take the refuse to the street and it is COLD.
whens the next EURO run
scott, comment 33, your heart surgeon is going to love you!!!! A bottle of hard stuff and 5 …. FIVE!!! …. packages of bacon?!?!
Very funny, especially if it is true.
Bburg Mike…. from what I have gathered the last couple of days, temps wont be an issue at all…. I could be wrong, but I think if it rains, it wont be very long….someone can correct me if I am wrong, but thats what I have observed….
I was waiting to see if anyone would comment on it, but no. Relatively new meteorologist lady named Montuori on Channel 10 at 6:20 pm gave a great visual description of what snow totals would look like around SW Virginia if first the GFS model were to verify, then using the 0Z Euro.
GFS: Blacksburg 0.9 inches, ROA a bit over an inch, Hot Springs 2.9.
Euro: Blacksburg 9.1 or so; ROA 9.9, Hot Springs over 12.
Jay Webb on 7 showed the colored bands approach, and ROA was in dark blue, which I think was something like 5-7 for Euro? That range might be off.
Curious.. what teleconnections do we have here? PNA+ NAO- and all the other things we look for when expecting a winter storm or is this a case of an Alberta Clipper taking a dose of steroids directly off the coast from us?
Matt: It’s where you would expect. PNA+, NAO-, AO-.
When did a 12 hour duration snow event become a “quick-hitter” ? Most snow lovers would consider that epic.
Flutie, comment 42, you may be right. The NWS/”7″/”10″ triumvirate and probably the TWC folks to a lesser extent have been way optimistic for both Roanoke and Blacksburg and probably all of SW Virginia for 3 days running, and I think/predict that tomorrow makes it 4. They are predicting 47 (TWC is predicting 50!!!) for ROA, about 43 or 42 for Blacksburg. I bet ROA tops off no higher than 43.
Made it back home safe. As usual, the snow gave out as soon as I crossed the state line.
So…what about smyth county?…looks like we are outside looking in?
Matt, Comment 44, here are today’s PNA, AO, and NAO levels, to give precise numbers to what KM just said. As a group, they are the most impressive combination since December 1. PNA: +1.1. AO: -2.2. NAO: -0.9.
Nice going, Snow Lover. Were the (cross)winds a problem while driving at any time?
21 currently with a strong gusty wind out of the northwest. Still having the blowing snow showers but tonight it looks like they are accumulating. Already have a dusting out there.
Doug – I was getting blown around pretty good on the way up, but nothing crazy. On the way back, blowing snow reduced visibility in the Flat Top area and around Princeton.
25 here on the river, snow has stopped. The jar is about to be raised if these models don’t find a solution soon.
Snocat: I don’t think many folks, at least those west of the Blue Ridge who have lived here for 25+ years, consider a 12 hour snow event epic. Very nice yes, but not hardly epic. Epic is ’93, ’96, or some of the 72 hour marathon upslope events that have occured in the high terrain. When you could conceivably sleep through an entire snow event, it’s not too much to get excited about.
And the “always reliable” Old Farmers Almanac says………………….for the entire Appalachian range. Mar 3-7: Rain, then flurries, chilly;
That ain’t gonna be right.
I think it-d have to be considered a clipper
until the mid and upper levels start to pull in
Atlantic moisture..or when the coastal low starts
to develop.
As I remember some of the big storms of the mid 60-s
thats what happened with many of them..
Slow moving clippers developed into a double barreled shot
delivering heavy bands of snow as a broad Northeasterly
flow established itself.
I can actually remember where I was standing watching
some of these heavy snow bands. It was incredible to see.
0Z NAM looks like decent snow run in SW Va. Low in NC instead of Va. Vort digs to I-40 or so. Still looks like central/northern Va getting brunt of it. Moving closer toward snowy Euro solution, definitely.
How’s this for a mixed signal…
0Z NAM SHIFTS SOUTH and hammers Central VA from the Blue Ridge east!
http://mag.ncep.noaa.gov/nam/00/nam_namer_060_850_temp_mslp_precip.gif
http://mag.ncep.noaa.gov/nam/00/nam_namer_066_precip_p24.gif
The purple on the map at hour 66 over VA is over 2+ inches of liquid precip…Even it is a bit warm the ratios would still be about 6-8:1…that is for every inch of liquid you would see about 6-8″ of heavy wet snow.
Question is…will the GFS follow suit to the NAM….tune back in around 11:30 PM
more shortly….
It’s a good time to check out the wind map.
http://hint.fm/wind/
Here’s hour 72 on the 0Z NAM….WOW!!! Jared French, do you have a snow blower? You may be measuring your snow in feet! Charlottesville,Roanoke, Lynchburg, NRV, up 81 to Winchester still look really good with well over a foot. Looks like we’ll even get a good shot of 8-12″ here in eastern Goochland on the west side of Richmond.
http://mag.ncep.noaa.gov/nam/00/nam_namer_072_precip_p24.gif
DT just posted his FIRST CALL map and Roanoke looks to be stradling the 8-12″ line with 12+ line….I think! All of Botetourt County was 12+, acording to said map. Kevin, if this all pans out, do you think they’ll issue watches and warnings tomorrow night or earlier?
DT issued his first guess map which is always subject to change and most times way off. He has most of Henry County in the 8-12 inch range. I love snow but am so pessimistic. I appreciate the blog and all the comments. I sure could use a snow day.
NAM just a bit too far east with snow field for much in SW Va. Heavy snow at Lynchburg, light amounts Roanoke and west. But the trend is toward the big Euro solution. Could be important step.
Captain Glen Quagmire: That’s crazy! I hope that’s the snow we get (:
Kevin: I keep looking at weather.com for Roanoke, VA & they say the high on Weds. is supposed to be 38 and the low 35. Could that change? Ive seen some forecasts with the high and low a bit colder than that.
Allan Huffman’s 0Z NAM Snow Clown Map
It’s very tight and only shows 2-3 inches for Roanoke…Don’t think this is correct. MR. French and John in R’ville are looking at over 25-30″
http://raleighwx.americanwx.com/models/nam/00znamsnow_NE072.gif
Key point is the NAM is coming around to the Euro’s way of thinking…
Temperatures on Wednesday are going to be driven by the dynamics of the storm. If you’re in the solid snow area you’ll be close to freezing. If not, temperature will drift up to mid-upper 30s. The storm will drive the temperatures, not the other way around.
This from WxSouth could be a very big deal in this forecast (thanks Zach Robinson for pointing it out)
https://www.facebook.com/photo.php?fbid=596193127077413&set=a.358160627547332.99358.356106867752708&type=1&theater
Translation: Vort max appears to be entering U.S. currently in western Montana. GFS modeled it entering in eastern Montana.
That could translate to a significant southward dig in its dive into the Southeast. If that is in fact the case, the Euro storm track and evolution is more likely to verify than the GFS and previous NAM runs. That would be your bigger SW Va snowstorm.
Any of you guys been to the accu weather forum, it’s crazy, they have to be looking at different models… going off on a tangent somewhat but if we have a good snow pack, has anyone noticed the next storm system rolling through. Thats a good amount of rain on top of that much snow.
It’s long range; however, thats 3 runs in a row the NAM has shifted the low slightly south. They all end up with in 50 miles of each other on the coast but the 0Z gets there through charlotte.
Julie comment #65 great observation. This is my biggest concern. If the snow is going to accumulate and more importantly we are going to maximize the snow to liquid ration it HAS to be no higher than 32. Yes it can, and will snow, at temps above 32, but it will have to work a lot harder to do so. Alot of snow lovers (especially those east of the you know what) are not coming to terms with the issue of these “warm” temps. No one east of the Blue Ridge will get more than maybe 6″, due to this factor. The further west and higher up you are, the more you will maximize your accumulations and ratios. I think Montery is the place to be this time around. Highland/Bath are probably the only counties that have a prayer of seeing more than 12″, and possibly alot more.
Thank you Robert Gramble at WxSouth and Kevin too.
Important to note that NAM still didn’t bring the heavy snows South or West of Fincastle/Bedford/Lynchburg. Still has to shift South significantly more to get Blacksburg/Roanoke in game.
NOT impossible.. Don’t know which one I’m rooting for. I don’t want snow because I stuck my neck out earlier with my call that says no snow South or West of Roanoke..but I kinda want to see some heavy snow haha..
Let’s watch the Vort Max over northern Plains.. We want it to go somewhere from Des Moine to Western Missouri to Paducah…good rule of thumb.. if snow shifts SOUTH of Chicago.. then the ULL will go further South than modeled.
Game on.
We are up to over 300 comments since the beginning of the previous thread about 7:30 pm yesterday, bloggers. Great work, WJN.
2-3 inch per hour snowfall rates will pile up if it’s 34 degrees at the surface … and chances are, if there is enough lift for those kind of snowfall rates in the core of the snow area, even east of the Blue Ridge, it will be 32 degrees as it snows. So I’m going to disagree with the point that it can’t snow more than 6 inches east of the Blue Ridge. Snowfall rates will overwhelm melt rate, and storm dynamics will overcome warmth at surface, which isn’t all that warm. We’ve seen this dynamic cooling thing at work twice in the past year (Jan. 17 and Feb. 19, 2012) and this storm will be deeper than either of those two.
But that’s not to say someone west of the Blue Ridge won’t get a foot if the snow band expands westward. The higher elevations will help with colder temperatures. Snow will stick more readily in higher elevations.
Just looked at satellite and radar shot of area of west cntrl
Montana..
and indeed the center of circulation appears to be
around the Helena /Great Falls area.
GTF currently has winds 340/22 gust 34..3/4 mi with lite snow..
Quags, comment 66. TYVM for posting the link to Allan Huffman’s clown map, but do you have any idea why he posts a map that does not include a great deal of SW Virginia but posts large areas of southern Canada? Very frustrating.
When you doing the snow meter Kevin?
Kevin, comment 69 piqued my interest. What is coming rain wise after this wet snow? Are we going from a heavy snow to a melt and possible flooding?
0Z GFS pathetic and must be ignored….
http://mag.ncep.noaa.gov/gfs/00/gfs_namer_075_850_temp_mslp_precip.gif
Thoughts on latest GFS run , more north but more precip….
0Z GFS Clown Map at hour 66 or March 6…
http://raleighwx.americanwx.com/models/gfs/00zgfssnowdepth066.gif
NO WAY…Go back to comment 68 of Kevin and click on the link to WxSouth. Explanation is there.
GFS was a bit farther south with low, but not really on board yet with NAM or Euro. Would be a minor snow event taken literally.
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Snow meter will be posted with my next blog entry whenever that is in the next hour or two. I will tell you I’m giving Roanoke and Blacksburg 7 flakes out of 10, consistent with my 70 percent chance of 1 inch plus noted above. I was going to do 8, but backed off a bit on earlier data today.
David: Looks we’ll have a few days of pretty mild temperatures before any rain arrives. Most snow will probably be gone by the time it rains, especially if we don’t get the foot-plus stuff.
Was I looking at the Oz wrong? I could have swore it was more north?
I think you mean north don’t you?
Regardless if we hit the motherlode in Roanoke, I think this is going to be the biggest-un we will get for this season. I do think it is likely that this is it also.
0z NAM further south, 0z gifs still north. NAM has come towards Euro. Seeing as how the GFS is already off in Montana, I think it more likely that the Euro is the real deal.
The low starts out in NC and drifts into SE Va on the GFS . I don’t recall it being that deep in NC before. I could be wrong. Precip area looks a little farther north.
GFS all alone on DC-NoVa bullseye now. My money would be on Harrisonburg-Charlottesville for bullseye.
Soooo tired, but I really want to know what the next run of the Euro says. I’m guessing a small shift to the south. Think I’ll take a 2 hour nap, and hopefully wake up to good news.
well I guess I have to wait on the Euro, I’m not going to be worth anything at work tomorrow….. 24F on the little river right now…..
Good pic of the vort moving into Montana courtesy Charlotte meteorologist Brad Panovich
http://twitpic.com/c8i51u
READ THIS PLEASE…From DT at wxrisk.com
https://www.facebook.com/WxRisk#!/photo.php?fbid=495057367208193&set=a.148807335166533.25889.129478830432717&type=1&theater
Folks there nothing to see on the 0Z GFS…move along…time for bed…
Euro will hold the course….
Word is couple other models trend north? UKIE?
Canadian model is a solid snow hit for SW Va.
UKMet was way south earlier, it could trend north quite a bit and still not be where even Euro has been.
Monday 0Z CMC Canadian Model holds with Sunday 12Z Euro! Stays South and is stronger.
I may have to stay up now to see what the Euro says…
UKMET is north…
Wow, things are heated over at the DT fb page. DT just dropped the fu right on someone. I am shocked at the lack of professionalism.
The trend tonight is towards a good hit of snow in Roanoke. Right now, Charlottesville looks to be the jackpot.
Please explain, Kevin.
Link to Meteocentre UKMET images from Monday 0Z run.
Ukie brings Low over Tidewater with a track on the NC/VA state line.
Still a great shot for snow in VA.
http://meteocentre.com/models/explorateur.php?lang=en&map=na&run=00&mod=ukmet&stn=PNM&comp=1&run2=00&mod2=ukmet&stn2=PNM&hh2=048&fixhh=1&hh=060
By saying the UKMET is north.. it really means it’s finally starting to come in line with the Canadian/Euro camp instead of being a very southern outlier.
MIcah…
In a nutshell, VA is still in the game for a very decent amount of snow. Ho much and where is still up in the air and we won’t know til about Monday night late. Right now, the GFS is having it’s issues as expected but in the last several minutes the Monday 0Z Canadian and British models came out and are leaning towards what the Sunday afternoon European model said and has said for several days now.
Now it’s a waiting game for the next Euro which will come out in about an hour.
The UKMET looked to be slightly west of the 12z taking the slightly west of the Kentucky state line. but it was hard for me to tell if it took the low north once past charlotte it was so close. It did however show the low start to form that the GFS did that might degrade the blocking high.
DT’s assessment of the Monday 0Z UKMET (British) model…
From WxRisk.com
https://www.facebook.com/WxRisk#!/photo.php?fbid=495070933873503&set=a.148807335166533.25889.129478830432717&type=1&theater
C’mon euro! Shower Roanoke with tons of snowflakes!
People are getting downright hostile on social media tonight. Kind of ridiculous.
Glen, it is amazing what the DC and north people are posting over at the DT. I have never seen such vileness towards a forecaster.
I just hope those northern wishcasters don’t invade Kevin’s page. Kevin, you will block them if they come on here and get vile won’t you?
Kevin are you going to post another update tonight?
I am in the process of putting up a news post. Then I’m going to glace at the Euro as best I can and go to bed. Lots of late nights ahead, hope to get at least one decent sleep.
I think it’s time to throw all the maps into a blender and see what we get. Before long Meteorologists will use quarters to make the forecast.
Oh yes, David, abusive and vile language is a total no-go here. It’s kinda silly to taunt people over a snowstorm that hasn’t happened yet (or, even one that has happened.) Will not be tolerated here.
Thank goodness for that. It really got beyond the pale over at wxrisk on fb.
euro south of last run
looks to amplify closer to shore as well…