Snow chance this weekend: Probably some flakes, probably not any shoveling for SW Virginia
Denver hit a record high of 80 degrees on Monday; two days later, Colorado’s Front Range has been bombarded by heavy, wet snow.
(Associated Press photo of wet snow on golden leaves in Colorado at left … larger version by linking here).
Roanoke hit 74 degrees today, which was not close to a record (86 in 1939 is the Oct. 26 record). Two days from now … I don’t think we’re going to see anything close to what Colorado has been experiencing, though it will be much colder.
We’ve been focusing much of this week on a potential low pressure system moving up the East Coast that might pull down enough cold air and throw back enough moisture for some snow in Southwest Virginia this weekend. Before we get to that, let’s note that we have one more mild day on Thursday, with increasing showers late in the day and overnight as a low-pressure wave moves in from the west. That low will pull a cold front through, leaving us with a raw, windy, maybe showery day on Friday — temperatures will likely get no higher than the low 50s on Friday anywhere in our region, with many places sticking in the 40s. There might be some snowflakes flying on the wind in higher elevations on Friday.
The same upper-level impulse that has dumped snow in Colorado will dive south and east, then lift north and east around a deep southerly dip in the jet stream this weekend. It is expected to help spin up a surface low pressure system that will move very near the East Coast Friday and Saturday. Forecast models are starting to come into alignment that this will happen — there had been a wider variance of projections before. As the low passes east of us near Cape Hatteras, its counterclockwise circulation will be drawing down cold air from the north as it continues flinging moisture inland, and it may be cold enough for snow to develop for a time, especially in higher elevations.
I do NOT think this will mature into a more widespread early-season (try pre-season) snow event for Southwest Virginia for the following reasons:
* Too much above-freezing air at the surface to overcome before precipitation arrives;
* Low likely too weak as it passes our latitude to pull down the cold air needed for widespread snow in lower elevations (below 2,000 feet);
* Low likely to pass a little too far offshore, just east of what would be a prime track for snow in our region, even in mid-winter.
* Both the weakness and eastward track of the low likely to keep the storm from throwing sufficient amounts of moisture inland to (1) cause heavy enough precipitation to pull colder air down from aloft and (2) to allow for sufficiently heavy snow to overcome preceding warm ground conditions for widespread significant accumulations. (Inset precipitation map for Friday evening to Saturday evening from Hydrometeorological Prediction Center shows the lightest green color, or less than 0.10 inch, over most of our region, with no more than 0.25 inch east of the Blue Ridge. If every bit of that were snow and it was cold enough for every flake to stick, that would be 1-3 inches at best … and of course, as I’ve noted above, it’s not likely all of it will be snow and absolutely certain that not all of it would stick.)
I do expect there to be some snow in higher elevations (3,000-feet plus) late Friday night and Saturday morning, maybe even some light accumulations, with snow showers and flurries gradually working down to lower elevations. Blacksburg, at just over 2,000 feet, will probably see some snowflakes, maybe even a dusting of white on grass and exposed objects. Roanoke, at 850-1,100 feet on the valley floor, might even get a few flakes at the end.
All of this is subject to change pending later developments.
October 26, 2011 - 8:56 PM
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Short take on this: A storm system has a high bar to cross to convince me it’s going to snow on us more than a few flakes in late October. The model trends and the overall weather pattern aren’t showing me that yet. I think it’s going to take something much stronger than a 1008-1010 millibar (29.76-29.82 inches of mercury) low a little closer to the coast to pull that off this time of year. There’s still 48 hours for things to change.
From DT:
SNOW or RAIN to SNOW for these areas ABOVE 700 feet western VA far eastern WVA
Roanoke’s elevation, according to Wikipedia, is 883 feet.
Close.
But I’m not convinced… yet.
Almost everything in this part of the state is above 700 feet.
But essentially, what he is saying is pretty close to my next to last graf above. I just think seeing ANY snow at the floor of the Roanoke Valley is very iffy.
Yeah, sure is fun for us snow lovers to get worked up over, but sadly I know it will not happen.
700 feet. lol even lynchburg is 800 I think.
Here is HPC’s take on where 4-plus inches can be expected from Friday morning to Saturday morning.
http://www.hpc.ncep.noaa.gov/wwd/day2_psnow_gt_04.gif
i.e, nowhere.
From Saturday morning to Sunday morning, a slight risk in one strip north and west of NYC:
http://www.hpc.ncep.noaa.gov/wwd/day3_psnow_gt_04.gif
Two things to note this morning based on a few quick looks at the GFS/Euro models:
(1) Heavier precipitation does appear to be somewhat more to the west late Friday. The new HPC map from Fri AM to Sat AM captures this pretty well, with .25-.50 expected in our region. http://www.hpc.ncep.noaa.gov/qpf/fill_98qwbg.gif
(2) There is somewhat of a weak wedge or cold-air damming situation preceding the arrival of the precipitation.
Those things, if they come to fruition, would click up the chance of significant snowfall a notch — not to the point of a widespread accumulating snow for the entire region, but increasing the chances that higher elevatiions get whitened and perhaps improving the chance that lower elevations will at least see flakes or light amounts.
Mr. Griggs, I’m with you on the TX/OK drought situation. I don’t see any big uns this year that will come out of the southern stream from TX or the Gulf unless there is a HUGE pattern change. This event is not that pattern change.
Kevin, did I hype this event? Don’t think so, but if I did, my apologies. Your assessment from above is more insighful than my
yada yada blah blah wawa wawa spewing of the mouth hype that I said this week.
Again, this will be a rain event for all of NC/VA with mountain snow above 2000′ north of I-64, regardless if the models (Euro in particular) shows the mother of all storms. If you see snow flakes south of I-64, consider yourself lucky.
For What it is Worth – I went to Google Earth and looked up some elevations -
Roanoke Times – 201 Campbell Ave. – on the sidewalk – 936 ft.
Oakey’s Funeral Chapel – Church Ave. -parking lot – 958 ft.
Mill Mt. Star – parking lot – 1735 ft.
Lynchburg – along river – 525 ft. and then it goes up to around 700ft. or so as you go away from river – I went up 10th St. It looked like the jail was at 660 ft.
Base of the Doppler is around 2700 ft.
This TWLS’er will be okay if there is no snow but I would like to see some rain.
This morning temperature driving on Tyler Rd. south of the Radford hospital was 60 degrees, 21 degrees warmer than it was yesterday. I told my wife not to put the rainsheets on the horses because it was too warm, and it didn’t look like it was going to actually rain today. So far it looks like I was right. The rain is trying to move in but seems to be largely dissipating coming across the mountains.
The upcoming Friday night event looks like a continuation of last winter, in that there is a weak southern stream wave that is not really going to phase with the northern stream trough until it’s largely north and east of Virginia. The model predictions seem to be following the trend from last winter too. Like last winter, the Euro 5 days out was way overblown with the intensity of the coastal low off VA, while the GFS did not catch on to the coastal low idea until a couple of days out.
D. Carol, I reckon you got your match handy. Got around 3-1/2 pickup loads in since Sunday. Still have more to get, but giving my back and shoulder time to heal up a little. What the wood gettin didn’t break, the window sealing and climbing ladders did. Figger your area will definitely see some snow, as will probably mine. And the top of da Knob is a good bet. More show than tell tho, even for us.
Can you say strong cold front boys and girls????
Two Facebook entries within minutes of each other:
Henry Margusity Fan Club
Snowing now across northwest PA into eastern New York. The rain/snow line is gradually shifting south and east across PA and NY.
Wxrisk.com
81 degrees at 1pm at chester va
Jason in Riner: Agree entirely with your 10:44 a.m. comment.
Weather Service says 1 inch of snow accumulation after midnight Friday night for Montgomery County!
I’m surprised someone hasn’t posted the GFS snowfall “clown map” from the 12Z run with its heavy snow bullseye up toward Staunton and Harrisonburg and 1-2 inches Roanoke and Blacksburg.
http://wxcaster.com/gis-gfs-snow-overlays.php3?STATIONID=FCX
NAM has a much different idea.
http://wxcaster.com/gis-snow-overlays.php3?STATIONID=FCX
So is it looking possible that the GFS is correct with the snow here (Roanoke) or are we still likely getting just flurries?
I would think unless it can come down pretty heavily for a couple of hours it would have a hard time accumulating in Roanoke Valley — it’s got to snow hard enough to pull down the colder air from above and overcome warm ground temperatures. And probably the first 1/2 to 1 inch still melts away (maybe not on grass and cars).
Above 2,000 feet looking more likely for some accumulation, with 1,200-2,000 feet on the fence. If the models keep boosting the precipitation amounts through tomorrow, rather than move them elsewhere or back off, there may be sufficient reason to re-think the possibility of a more widespread snowfall.
Actually Kevin the 18Z NAM came in looking more like (or worse than) the GFS…
Some people are calling this the generator storm because of all the power outages likely if it comes to pass with heavy wet snow and many leaves still on the trees…could be very bad for some folks.
I think I’ll just make a big pot of chili and stay in and watch football on Saturday…
New NAM clown map is ridiculous.
http://i43.tinypic.com/v4sdoj.gif
1 to 3 inches in Roanoke? Not happening!
Brandon: The map you posted actually shows 4-5 inches for Roanoke.
If it snows hard enough at the right time, it COULD happen.
Saying stuff like that, I feel like we’re reliving the late March storm that didn’t materialize.
HPC on board with slight risk of 4-plus inches:
http://www.hpc.ncep.noaa.gov/wwd/day2_psnow_gt_04.gif
The word for last winter was BUST. I bet this apple doesn’t fall far from the tree.
This is absurd.
There is a tension in weather prognosticating between “persistence forecasting” — presuming that the recent past holds the best key to the near future — and too much re-fighting of the last battle. I think too many of the ’10-’11 projections for individual systems, including my own, were too high because of using the ’09-’10 winter and its abundant snowfall as a template. It’s a brand new season. Trying to see it on its merits. My caution with this is based on October snowfall history, hopefully not on getting burned a couple of times last winter.
wdbrand – yes, the match is handy. We are set for the winter with wood. Brought in (the house) yesterday a couple more armloads to top off the wood rack. I was envious of your red oak you cut the other day. That is El Primo wood. The generator is ready to go too – to keep the freezers and refrigerators going. Always good to be prepared – just in case the weather does turn bad. There is always that “first time” for everything (significant snow in October).
We cannot ignore the fact that the NAM, Euro, and GFS are all in agreement with a fairly major snow storm (at least for October!). The snowfall map for the NAM shows our area getting 3-6″,and parts of VA getting 10″ plus (ridiculous, I know). Also, cannot ignore the HPC predciting 4″ plus probability for our area either. Kevin, when if ever, will our local Mets make it known to the public what they are seeing on these models? Is it just to ridiculous to mention? If that is the case, I guess they will simply be nowcasting Saturday morning when we are all looking out our windows saying “what the h…..”!
Trying to outguess what the models are NOT showing is part of it. A map that would like prime for snow in January sometimes doesn’t hold for late October because of deeper/warmer surface boundary layer to overcome. And I’m sure many are hesitant to pull the trigger on a relatively big snow for Oct. 29 based on (1) it so rarely happens this time of year and (2) getting burned a few times last winter. BUT … if these models are continuing this trend overnight, I think you may see some advisories or even watches going up by morning.
One thing the models do show that makes me a little hesitant, at least for the Roanoke Valley, is that none of the models show the 2-meter temperature, which is where the surface temperature, getting to 0C or 32F, the freezing mark, anywhere in our area. That usually is a little too warm for higher elevations, and it can snow and even accumulate at 33-34 degrees IF it snows hard enough, but that does give me a bit of pause. Will the dynamic cooling from the developing storm and the falling precipitation cool that boundary layer enough to get the heavier snow into the Roanoke Valley?
wdbrand – I went to Google Earth and found Twelve O’Clock Knob Rd. I went from Rt. 221 up to what I hope was the top and the elevation got up to 2528 ft. – that is on the road – before it started dropping.
I may not be paying close enough attention, but unless the forecasts get a lot worse, won’t any snow that falls (and/or accumulates) be gone Saturday afternoon?
Mark in Pulaski
To borrow the quote from the Movie “Airplane” & Lloyd Bridges (kiddies look the other way, please) “Looks like I picked the wrong to quit drinking.”
Still not fully believing any of this. This will be an elevation wet snow, nuff said.
(shaking my head…)
Mark: Yeah it’ll be gone quickly. May top 50 Saturday afternoon. No snowballs for Halloween!
What fun!!! With all the funny guys and gals, including many of our beloved “reverse hibernators” now back in the mix, Kevin is in 7th Heaven with all the blog hits. I love the term “clown maps” that a couple of you have used. First reading the phrase made me laugh out loud, then what they are showing made me laugh even harder. I think that several of these models take a look at what is happening aloft (LOTS of cold air up there) and overlook or vastly underestimate what the surface temps are like. In My Not So Humble Opinion, there is NO WAY that snowflakes will accumulate anywhere below 1500 feet in the Roanoke Valley. There may be some lonely snowflakes that melt on contact in the wee hours of Saturday or around dawn, but I doubt that even that will happen. The ground is very, very warm, and so are the lowest levels of the atmosphere.