Some lingering doubts about Friday snow potential
You will be waking up to a cold morning, with 5-15-degree readings in many locations, especially west of Roanoke. The coldest readings will be wherever geological features can shelter a lower-lying area from the wind and there is also some leftover snow cover.
There may be some chance of light snow on this Wednesday evening as an upper-level disturbance zips by. The farther north and west you are relative to Roanoke, the better chance you have of seeing some snow, possibly enough to whiten the ground.
I spent much of last week reminding folks about a southern-stream disturbance that seemed to be written off but ended up turning into a big wet snowstorm for most (not all) of Southwest Virginia. This week, I’m switching roles, continuing to be somewhat skeptical of a northern-stream disturbance that at least some have given a solid shot at a 4+ inch snow by Friday. I do think it will probably snow over most of Southwest Virginia on Friday, and many spots may get enough to cause some travel issues, but I remain unconvinced about a larger, more widespread winter storm. There continues to 
be some uncertainty in just how much moisture the system will spread over and into our cold air — the depth of cold no longer being the issue — and also about whether the system’s energy might jump from an inland system to a stronger offshore one. The NAM and GFS models from Tuesday evening illustrated my concerns, though of course, at this still early stage, I’m not sold on these being the correct solutions, yet. The NAM carves out a lighter area of precipitation at least east of the New River Valley (total NAM precipitation totals through Saturday morning linked here, and inset at left ), and only about a tenth to quarter-inch of liquid equivalent from there westward. That could still translate into a 1-3 inch snowfall, maybe locally 4 with possible higher snow:liquid ratio due to the deeply cold nature of the atmosphere. Far southwest Virginia, west of I-77, would see the most under this scenario, though some of that would also be from upslope snow showers that follow the initial wave. The light green farther east, roughly Roanoke and east until central Virginia, would be less than a tenth inch of “rainfall,” or likely an inch or less of snow. The GFS, linked here, is even drier. Also, there may be some tendency for the dominant high pressure forcing the Arctic air to push the heavier precipitation southward into the Carolinas. (Late information: The European model seems to be still on board with a widespread moderate snowfall [2-6 inches] for Friday. Still have doubts, though, about 4+ amounts, especially east of I-77.)
There is still plenty of time for this situation to change. The models have already bounced back and forth to several different versions, though many of my hesitations with this event are more about historical trends on similar systems, not what the models are showing for the near-future. Earlier Tuesday evening I wrote this Weather Journal column suggesting 2-4-inch amounts might be reasonable – and they still would be with only a slightly more moist and/or northerly-bumped precipitation swath than what was depicted on Tuesday evening’s models. For now, I’m thinking light snow amounts, mostly, 1-2 inches, for Friday more near Roanoke, maybe a bit more in spots New River Valley and west . We’ll keep watching it to the end, of course. It’s a setup that doesn’t scream “winter storm” at me — low-pressure systems approaching us from the due west, especially those of northern stream origin, rarely are big snow makers here – but could at least whisper some accumulating snow.
January 23, 2013 - 1:24 AM
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The new 0Z Euro paints a 3-6″ swath of snow over Southwest VA. Before anyone gets excited, recall that this is the same model that was showing snow up into DC with the last storm. They got nada. At this point, we need to consider the Euro and outlier. I’m with Kevin on this one. Very skeptical.
Euro looks best for snow west of Roanoke, then sort of a jump with light amounts to the coast.
Brandon, you got a good map to link? I ran it on wunderground but it doesn’t have totals map.
I no longer have access and have not seen it myself. I got this information from DT’s Facebook page:
For southern WVA SW VA including ROA the model shows 0.25 -0.50″ liquid which would be 3-6″
We’ll see if next 24 hours turn me over to the somewhat-bigger-snow side on this. Euro was off on aspects of last storm but of course has the best track record overall.
The farther west you are from Roanoke in Virginia, looks like your chances of seeing multiple inches are better. And it’s not over for Roanoke or anywhere in Virginia, really, yet.
Kevin, what are these models showing for central Ohio ?
I GUARANTEEEEEEER Greene doesn’t get any snow under the Death Star Forcefield! LOL The force is not strong with Greene, unless you need a Heat Ray. Low was only 15 after being forecast to be low teens to upper single digits.
Back to the historical trends, west is best and east is least with the Friday storm. Looks like no snow north of I-64 and east of the blue ridge. Poor souls.
Morning update:
I’m not the only one with these doubts. HPC reduced from a wide area of slight-moderate risk of 4+inches in its snow forecast yesterday to a narrow slight risk sliver west of I-77:
http://www.hpc.ncep.noaa.gov/wwd/day3_psnow_gt_04.gif
The NWS-Blacksburg forecast discussion prominently mentions reducing expected amounts to average of 2 inches across the region:
http://forecast.weather.gov/product.php?site=NWS&issuedby=RNK&product=AFD&format=CI&version=1&glossary=1&highlight=off
And the HPC winter weather discussion now mentions the possible “jump” from the Appalachians to the coast:
http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfhsd
BUT … positively for snow lovers, that same HPC discussion also makes it clear that better model consensus may develop as the disturbance offshore in the Pacific moves over inland areas and becomes better sampled.
AND … the 6Z NAM has now come in a little more moist over the southern 2/3 of Virginia, showing the second lightest shade of green, or 0.10 to 0.25 inch of moisture, a general 1-3-inch type snow area (though a small bit of this 84-hour total, especially north of I-64, is from possible light snow overnight into Thursday morning with the first weak disturbance I mention).
http://mag.ncep.noaa.gov//Image.php?model=nam&area=namer¶m=precip_ptot&cycle=06&image=nam%2F06%2Fnam_namer_084_precip_ptot.gif
Here is the new NAM for early Friday evening, showing the 0.10-0.25 inch having fallen in the last 6 hours over essentially all of our region:
http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfhsd
So we’ll see where this goes.
14.5* here. WDBJ7 sure has reduced their forecasted high for Friday! From 38* 24 hours ago to 30* now. They are predicting a Friday morning event, 1-2 inches. Didn’t say if that forecast was for most of their viewing area or just the Roanoke valley. Gotta go.
7* this morning…boy the chihuahuas did not want to go outside!!
Noticed the NWS has changed my forecast back to snow/sleet for Friday and Friday night…was just 100% chance of snow only last night…what does that reflect,you suppose, Kevin??
My concern is the NWS giving a 100% chance three days out may jinx us. Too many potential snows have fallen apart within 24-72 hours to think they would say more than 70-80% confidence. But I guess they only said 100% chance of snow, not 100% chance of how much.
It was 9 earlier this morning but is now down to 7. Brrr!
I am planning to drive to Richmond on Friday and would like not to have to deal with snowy roads. As much as I like snow, it can wait til next week as far as I am concerned.
Winds in our neck of the woods were just enough to keep the radiational cooling from taking hold…temps were 16 degrees this morning after I fully expected it to be around the 10-degree mark, or possibly high single digits…based on the dew point. At least I didn’t have frost to scrape off the car.
Do we have any idea what the timetable is for this event?
8 in Lexington this morning.
Finally bottomed out this morning at 14*. Although it was cold, I, too, was grateful for the lack of frost!
NWS has sprinkled in some sleet nearer the Va-NC border, Clarkdocvet. Figuring out where the sleet mix line encroaches into the snow is a pretty inexact thing. I wouldn’t be surprised if that flopped in and out of your forecast.
The snow percentage for my zip code on the point-click forecast slipped from 100 percent to 90 percent for Friday, but remains 100 percent for many locations.
Right now, I would expect a widespread LIGHT snow event for Friday, something on the order of 1-3 inches. Closer to 3 in New River Valley, closer to 1 east of Roanoke. More than that west of I-77.
The doubts I express above are not necessarily permanent skepticism, just seeking a bit more evidence today that moisture will be just a bit richer and more widespread than several indications. And it will take only “a bit.” A couple tenths of an inch more moisture can take this from a low-end winter weather advisory event to a possible winter storm watch/warning event.
Ryan: Looking more likely to be Friday afternoon/early evening now. Most guidance has shifted a bit later.
Trevar, I was kind of irritated at the jump on 100% chance of snow as well. I’d rather see them do a smaller percentage chance and take it up as we get closer than a larger percentage and take it down. Not only does it make more sense in the forecasting realm, it also makes for less disappointment for those looking forward to snow!
Bottomed out at 13 on my thermometer (1400 feet elev, a couple miles south of Roanoke). ROA airport low was 18. Blacksburg airport dipped to 16, so guessing NWS official low ends up 13-15 for Blacksburg.
I’m heading to Bryson City, NC on Friday morning around 9AM. How do you think this event is going to affect me? I looked at the forecast for Asheville and it didn’t seem bad until the evening.
The farther south you go, Jon, the more chance of mixed precipitation rather than just snow. Does look like more of a Friday afternoon/Friday evening situation. May not be any closer than about Nashville by Friday morning and then rapidly spread east or east-northeast.
Thanks,Kevin..I sometimes forget I’m only about 10 miles as the crow flies from the NC boarder…hope it all stays snow.
I am not really crazy about seeing any snow. Our area because of the mountains is one of the hardest areas in the country to predict weather for. The mountains have a big influence on the high and low pressure areas as well as the Jet stream. Over the past few years we have all saw times that areas west of us have gotten covered with snow and we haven’t gotten anything. The same goes for the Carolinas. A lot of it I guess depends upon the elevation of the particular system when it reaches the mountains.
New NAM (0Z) shows the .10-.25 inch liquid, or very approximately 1-3 inches of snow, from about Roanoke south.
http://mag.ncep.noaa.gov//Image.php?model=nam&area=namer¶m=precip_p48&cycle=12&image=nam%2F12%2Fnam_namer_066_precip_p48.gif
I think that 1-3 inches of snow just barely gets to Bedford on the 12Z NAM. It’s really hard to believe I am still waiting on my first 1+ inch snowfall here. Heck my largest snowfall so far this winter was 0.2″ on December 29.
Alvin: The mountains do affect low-mid level weather features. The jet stream, however, is at 30,000 feet, while our highest mountains in the Appalachians peak at almost 6,700 in North Carolina (and nearly 5,800 at Mount Rogers in Virginia), so the mountains don’t affect the jet stream much. It is driven by large-scale weather features on a continental/hemispheric scale. Generally speaking, the larger the weather features involved, and the more rooted in upper-level atmospheric synoptics, the less the mountains factor in.
In this particular case, there will be some differences between high and lower elevations in the amount of dry air overhead, which affects how much snow reaches the surface, favoring higher elevations. And there may be some upslope/downslope effects, as well as some of the storm energy jumping from the mountains to the coast. Temperature differences from high to low elevations are not likely to factor in much, as they do sometimes, because it will be below freezing everywhere (or even if it creeps to the mid 30s somewhere, temperatures will fall quickly back below freezing with the onset of any precipitation).
Weather channel this morning and Channel 7 both have us in the 3-6 inch realm of snow. They are thinking more snow now!!
Comment #31-In looking at Channel 7 website I don’t see anything about 3-6 inches. They say a one to two inch snowfall.
Some light snow in Chicago this morning… Heading back to Roanoke later today
The 12Z GFS looks like it a 1-3 inch snow event as well for Friday.
Margusity got us in a 3-6 swath for Friday
http://www.accuweather.com/en/weather-blogs/meteomadness/sneaky-snow-and-friday-snowmaps-for-both/4716626
Wow the 0z name looks like it has a huge dry slot near the lake. Seems like a lot of ice with that model
The new 12Z GFS is in, and it shows more moisture than the last few runs did. It’s not exactly on par with the Euro’s 3-6″, but for snow lovers, it’s a much better run than 00z.
At this point, my guess would be a general Coating-1″ Roanoke with more (2-3″) west and east. The GFS also shows a bit of a gap along and just east of the Blue Ridge.
From DT’s Facebook:
CONCERNS .. The air mass over NC VA MD DEL s NJ southeast PA will be very dry… There will be a lot of VIRGA… snow in the clouds NOT reaching the ground. And this is NOT big or even moderate system. This whole thing COULD still fall apart.
On the other hand this event appears to have slowed down a bit and will last a little longer. And the snow ratios will be 12 or 16:1
Bottomed out at 16.5 in Goodview, 14.9 in Jordantown. Hopefully we can lose the snow whole moniker with this storm.
12Z GFS is hugely more moist than previous GFS runs. 1-3ish over a wide area.
Brandon: Agree with DT entirely on what you posted of his.
I’ve got people popping in around here at work wondering what Kevin is saying about this upcoming snow system LOL. If nothing else, I’m training them to believe in what Kevin has to say about these systems. Of course, we are ALL hoping for snow. Snow days are awesome!!!!
Here is a link to the 12Z Canadian model. You can see what it’s projecting hour by hour. If you look at hours 54-57, you can see a hug gap in the moisture. Roanoke and Lynchburg are both in this snow hole.
http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html
12Z gfs is awesome for Feb 6! I know they are inaccurate this far out, but man its fun to see the chance of a snow bomber out in the future!
Sorry to turn this into the Dave Tolleris Show, but I don’t have access to the Euro.
DT:
*** COMMENTS ON 12Z JAN 23 EURO …FOR JAN 25 ***
12Z EURO HOLDS COURSE… shows two 6 hours periods of snow over OH WVA VA MD DEL northern NC …southern PA and S NJ… the MODEL shows 0.10 to 0.25″ in the 6 hour periods…. which is like 1-2 or maybe 1-3″ of snow.
Over WVA and sw VA … from ROA west the total liquid is 0.25 to 0.50″ would be like 3-6 or 4-8″
I will not be surprised at all if this storm ends up producing very littel because of such low dew points. Hoping for the best, expecting the least. I should copyright that phrase and put it on my Southern Virginia Snow Lover t-shirt.
http://blueridgeweather.blogspot.com/2013/01/friday-light-snow.html
Some quick thoughts on my blog!
The Chapel bottomed out at 10 this morning and Bristol was sitting at 23 and that was under approaching cloud cover. Our NWS forecast is for Snow, Sleet and Freezing rain mixing with rain in the pm. High temps around 34 Friday. Once again influenced by our southerly location. We fall within the 3-6 inche range in the Accuweather’s model.
Just a few renegade snow showers about a half hour ago. Too much wind to allow them to land. Right before they came the sky had that look of “snow”.
At least Friday is not looking like last Friday. I still have snow from that storm.
KEVIN,
I have seen AT LEAST four different sources putting montgomery county in the 3-6 inch range. According to you..that is VERY high.. i think so too. Any possibility of that happenning? and what about timing?
Braydenofbtown: Oh, 3-6 inches is definitely well within the realm of possibility. The Euro seems to be consistent in the range, other models are maybe a notch or 2 below and have gotten more moist today. Moisture flow vs. extremely dry air is the question. That works both ways. First, how much of that moisture does the dry air simply eat, snow that doesn’t reach the ground? Secondly, though, the dry air is part of the very cold Arctic air mass that dominates our atmosphere, and that extremely cold air may mean a greater snow:liquid ratio, which may mean you can get 1.5 inches of snow for the same moisture we usually get 1 inch of snow out of. The snow is fluffier, more of a crystalline structure rather than mushed together like last week, and a bit more airy as it accumulates, so it piles up deeper with less moisture.
If today’s models are on the right scent, snow lovers should like the trends. Will take a closer look myself a little later. Wanted to raise some questions today before there was a headlong rush to anoint the next winter storm that 48+ hours out that may or may not live up to its billing.
What cold, bitter temperatures? We used to have winters around here with highs in the mid 20′s-mid 30′s and it was way more normal and no big issue was made of it. Sure, they were below normal for the time and now….I do think our normal highs from December-March have edged up a hair in the last 10 years or so, because I remember when our normal high bottomed out at 42-degrees in the 1980′s, now it bottoms out at 45-degrees, 3 degrees higher! My point is, even though I think many places are having truly Arctic weather, why is it that when Roanoke has a high of say 33-degrees now, Katey bar the door, Arctic outbreak…BRRR…it is no big deal…REALIE! Our low of 19 and 18-degrees…BIG DEAL….what happened to lows and 12 and below! Why is the media in the region acting like highs in the upper 20′
s and 30′s is so cold…IT IS NOT!! We have had two days this winter were the high was below 40.
Allan Huffman’s thoughts about the Friday event:
http://www.examiner.com/article/discussion-of-winter-weather-event-for-friday
Now after my temperature rant….do you think we’ll get a WWA or WSW out of this Friday event. I have heard many source call for 2-4 or 3-6″ zone all subject to change for the higher or the lower!
Thanks. That was a ton if help! Like your thinking about not starting a riot.
Who are you ranting at, Scott? All it says here is that it was a “cold morning.” No reference to bitter cold. An air mass is “Arctic” based on its region of origin not precisely how cold it gets. Temperatures averaged more than 10 degrees below normal on Tuesday. That’s Arctic cold, whether or not it measures up to a particular cold wave of the past. Kinda like saying we didn’t have a heat wave last summer because it only topped out at 104 on 1 day when in 1983 it was 104-105-104 on 3 consecutive days.
As for your second question: Winter weather advisories are likely. Winter storm watches may be possible depending on how the next couple of days develop.
Well…TWC has bumped us down from SOLID SNOW for 2 days to PM SNOW SHOWERS. I look for other sources to follow suit in lighter amounts. Well..there is always February to finally get a good one!!
I jest saw 3 flakes fly fleetingly fast from fridgid Floyd farm fields.
To see snow, click here: http://www.resortcams.com/webcameras-snowshoe-shavers-centre.php
(if the camera is working)
HPC has one oval of slight-risk 4-plus inches for the 24 hours ending Friday evening, basically Roanoke / Blue Ridge and west:
http://www.hpc.ncep.noaa.gov/wwd/day2_psnow_gt_04.gif
But also has only a mid-range chance (40-50 percent) for at least an inch in the same time frame.
http://www.hpc.ncep.noaa.gov/pwpf_24hr/prb_24hsnow_ge01_2013012400f048.gif
Still some mixed feelings for federal forecasters on this event.
Was just ranting about the temps Kevin from various sites and things I’ve seen on TV. Nothing to do with you or DT. I am sorry, I simply don’t think 33 is bitter cold like some people have alluded to. Yes, it’s bitter cold for someone from say Hawaii, but this used to be more of a norm to have many many days with highs in the upper 20′s and 30′s and now it seems like some sort of icy anomaly!! Maybe the climate is warming!!! I realize many places are suffering truly brutal air below zero that I want no part of, they can have it. This Arctic outbreak has been publicized for ages it seems and it modified greatly before it got here. I am just wondering why some sources and peep think this is so cold for Roanoke!
It is definitely NOT a bitter cold outbreak here, Scott. I won’t put the word “bitter” into it until I see widespread single digits.
Scott, You already got a snow and looks like your going to get more unlike here of course where it looks to do absolutely nothing. BIG SURPRISE!!! I do understand what your talking about the temperatures with everyone talkling about low teens and single digits. Guess it wasnt as cold as everyone thought. Seems Joe Bastardi and DT are liking the first week of February because Joe said its going to be colder then this past go around and DT is conjuring up another Big Storm in his mind. LOL Oh well that first week of February might be my last chance of seeing snow this winter! It really sucks that in the last 3 years I can count how many inches of snow we have had here on one hand! Its just Nuts!!!
Well, it looks like the National Weather Service in Blacksburg is only calling for about a half an inch Roanoke/Blacksburg and northwest, and nothing south and east.
http://blogs.roanoke.com/weatherjournal/2013/01/some-renewed-doubts-about-friday-snow-potential/snowmap0123/
OK, this map is actually for TONIGHT and THURSDAY MORNING — not this storm we’ve been bantering about for Friday. It’s possible the little clipper overnight and early in the morning could whiten the ground for some folks. Don’t be shocked if you see flakes (some have already reported seeing a few).
The sky here in Salem looks as if it might open up with snow at any moment.
Kevin..
Weather Journal link says..”Chances are growing for late-week snow”
then below Weather Jourmal says “Some lingering doubts about Friday snow”
Fencing?
Not fencing, Joe, timing. Weather Journal column is written with Tuesday afternoon deadline. Chances were growing, then. Weather blog is whenever I can/want to update. Overnight data stoked some doubts.
Actually, they’re both still true. Chances have been ticking upward that we will get some measurable snow Friday, but I still have lingering doubts.
26 currently and the skies are mostly cloudy. Still a tad breezey. We probably only got up to 32 here today.
Coldest low of the season this morning was 6.4 up here.Now its 24 and not much wind blowing.It is not quite as bad as this time last evening.Fridays storm probaly won`t do anything up here but i`m used to that by now.
It will be an unbelievable run for the DC area if it experiences its FOURTH winter storm miss to the SOUTH since last February. Winter storms are supposed to miss north — not south, that frequently.
Looks really like theres theres not much moisture
to work with,,and whats there looks largely to
be projected to slide south and east of the ROA valley..
If RDU stays cold enough they stand a chance to get more
winter precip it seems.
Looking at the national radar http://radar.weather.gov/Conus/full_loop.php
you can see where that clipper has a bead on Pocohontas County and Snowshoe’s webcam will confirm it: http://www.resortcams.com/webcameras-snowshoe-shavers-centre.php
Just posted new entry about tonight’s brush with snow and continued discussion about Friday. (John, be sure and repeat that resort cams link on the new thread)
Checked out the Snowshoe webcam from above. Now THAT is probably ridiculous bitter cold with wind. Us here in VA just have a small version of cold. That place has to be the coldest place south of the Mason-Dixon line. You definitely don’t want any exposed skin there.
DT first guess map is out! He learned his lesson from the last storm and has no snow over our area of Virginia. HAHAHAHA our Death Star Forcefield is just to strong for Old Man Winter! Someday a Jedi will come along and use the Force to end the evil Forcefield, however I don’t think it will be this winter! HAHAHAHA I think I’m losing it fellow snow lovers! LOL