Slushy Sunday: More early or late?
Today and Saturday will continue to be below normal in temperature, but highs in the 40s today and maybe even some low-mid 50s on Saturday will feel a little milder after Thursday’s almost ridiculous early spring cold afternoon. There will be some more clouds on Saturday … and perhaps a small chance of some rain/snow showers, especially south of Roanoke, though most of it will stay south of us.
Looking ahead to the Palm Sunday storm, forecasters and forecast models are differing somewhat on whether the front side of Sunday’s storm — during the day — is where we might see significant snowfall, or whether it will wrap around the back side on Sunday night. Count me now as standing heavily on the 
front-side side of this discussion. In my opinion, the best chance at seeing a few inches of snow from the Roanoke and New River valleys south and west will lie with precipitation bands moving into the banked cold air along and east of the Appalachians on the front side of low pressure Sunday morning into the afternoon (the 12Z NAM depiction of precipitation as it would appear on radar early Sunday afternoon is at left). This is where it appears there will be the most moisture, which, falling through colder, drier aloft, will enhance evaporational cooling. Also, it could provide snowfall rates sufficient to pile up on a ground that, despite recent cold weather, will still be holding some warmth from the higher sun angle and longer hours of sun of early spring. The thing about the front side, though, is that is possible warmer air aloft could be pulled in, changing precipitation to sleet and rain and shutting off the snow rather suddenly. Depending on how this battle between warm-air advection and cold-air wedging transpires, a sharp rain/snow line may develop somewhere across or near our region, where locations to the north or northeast stay in snow hours longer than those to the south. Wherever snow falls, higher elevations are likely to see it earlier, and also likely to collect deeper accumulations than lower ones.
I’m not too confident the coastal low will develop early enough or strongly enough to be a major factor for us, and don’t expect more than patchy light precipitation wrapping around on Sunday night and early Monday. But be aware that some models have shown the coastal low, teamed with an upper-level impulse, adding another round of snow late Sunday and early Monday .
This is another in a long series of murky winter weather situations. I think most of us see some period of wet snowflakes, but this could easily slide toward mostly rain/sleet mix or toward a heavier snow with only subtle atmospheric differences.
Here are my probabilities of specific snow accumulation levels at Roanoke and Blacksburg:
At least 1 inch: 60 percent; 4 inches, 40 percent; 6 inches, 20 percent; 8 inches, 10 percent.
Chances are less to the south and greater to the north. Maybe add 10 percent for each 20 miles north, subtract for each 20 miles south — excluding 2,500+ Blue Ridge elevations south of Roanoke that , as typical, will have better chances of accumulating snow.
March 22, 2013 - 12:11 PM
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I will be off the blog quite a bit through the afternoon and evening. I will approve new comments from time to time. I may not get back to too many questions though, and likely won’t put up an entirely new post til Saturday.
Will be on WVTF (FM-89.1) at 4:30 p.m. to discuss the weekend snow threat and ongoing cold spell.
Kevin,
I am flying out of Roanoke Sunday morning. I am under the impression that any significant weather won’t occur until later Sunday, but what are your thoughts? Any chance of me having flight issues with a 9:00 am Sunday departure?
Take a much needed rest Kevin! You know the blog will be hopping this weekend LOL
What will the path of this storm be Sunday Night? I am most concerned with 77N into Western Pa, 81 North to NY, and 95N all the way up the coast to Maine. Haven’t been able to follow so any help anyone can provide would be very helpful to pass along to our 1200 guests in C’burg this weekend.
Well, the Euro and Canadian are in:
For Roanoke, both of them show 5-7″ falling, maybe 3-5″ on the ground, EXCEPT … both of them show it coming later (Sunday night-during dark, unlike the GFS/NAM advertising for daytime Sunday. If it is after dark (mainly), then we could see it accumulate sooner and better. And, EXCEPT, if the NAM is right … the intensity will be quite strong late morning Sunday. That kind of intensity does not mind ground temps so much. But, then, if the NAM holds, we’re talking about a different kind (depth) of snow anyway!
Euro and NAM has snow area going SW of Roanoke down to high country of NC pretty good. Canadian and GFS does not, which makes me skittish about them some. I would think post storm upsloping would be more significant.
Keeping in mind the GFS, though, I think we’ll end up with 3-5″ in the area. 3″ for the valley floor, and southwestward. Higher elevations near and in Roanoke, and Botetourt northeastward could get 4-6″ easily, maybe more.
I still can’t wait to see if and when the NAM humbles itself eventually.
Nurse Snow: More work-related (non-weather) than rest.
Alex: Most models suggest beginning near the time of your flight, but keep in mind, it could well be rain/sleet/snow mix, or non-accumulating snow at that time, and may not affect your flight. Check roanokeairport.com or call your airline that morning.
Dwayne: The snow area will be moving northward into Pennsylvania as well, where it will more certainly be snow.
Wally: I may have to reconsider my thoughts based on the Euro/Canadian. Although … HPC has moved more the direction of early snow vs. late snow for us, at least immediate Roanoke area.
1-inch map thru 8 p.m. Sunday: http://www.hpc.ncep.noaa.gov/pwpf_24hr/prb_24hsnow_ge01_2013032300f048.gif
1 inch map thru 8 p.m. Monday: http://www.hpc.ncep.noaa.gov/pwpf_24hr/prb_24hsnow_ge01_2013032300f072.gif
NWS-Blacksburg more on the snow/sleet early idea, too.
“MIX OF SLEET AND SNOW IS EXPECTED WITHIN A TRIANGLE BETWEEN FLOYD…LEWISBURG AND LYNCHBURG. BY SUNDAY EVENING…THE COASTAL PART OF THE MILLER-B SYSTEM WILL BE FAR ENOUGH EAST TO NO LONGER HAVE AN INFLUENCE ON THE REGION.”
… Will be off for a while. Back in a couple of hours.
Yes, well I’m nervous. The scary part is, in some cases (models), there is high gradient variations right near us, where amounts 4-8″ is very near points of 2″. It wouldn’t take much change in either direction to bust my best guess. But, we’re all kinda used to that in this region. B-)
I like HPC, but I sometimes find that just don’t think “locally” enough for me. I actually put good stock in the local guys at Blacksburg who KNOW our area and terrain. They have additional tools like BUFKIT to help them. I love the Weather Channel, but even they are too broad brush at times.
Kevin…reading the NWS forecast discussion gives me very low confidence in the chances for snow in my neck of the woods, given the mentions of the warm nose impacting the mountains and an expectation of plain rain outside of that triangle. This could wind up yet another storm this season in which Roanoke sees more snow than Blacksburg…possibly.
For my house in Pulaski County, I’m giving the following odds:
0-1″ 80%
1-2″ 15%
2″+ 5%
I would actually settle for a cold, soaking rain with plentiful QPF so that the slight dryness of February and March could be offset, going into warmer weather whenever that happens.
Dwayne: Sunday looks bad for travel northward any way you cut it. If I were one of those coaches, I would have my kids out of there and on the road home as soon as possible or hold them in C’burg until Monday morning late. I doubt all of your swimmers will be there for finals on Sunday night. Good luck, you have your hands full.
Yes, Wally, I got 4 1/2 inches of snow at my house in early February in an HPC 0% risk area.
Other John: Roanoke has occasionally gotten more snow than Blacksburg in some events over the years, but the strange quirk this winter has been the snowing-at-Roanoke/raining-at-Blacksburg phenomenon over hours. And yes, indeed, if the warm nose/cold air wedge boundary is positioned just right, it could happen yet again.
Clouds have moved in after a cool day. Was down to 13 at 5am and may have dropped further before dawn. Quite a chill for spring. Looks like the snow will be to our north but we may get some on the backside. Weatherman saying we may get some tonight. No major accumulation.
North versus South will be much more important than up versus down with this system. For example, Lexington, VA at 1,060′ will see more snow than Beech Mtn., NC at 5,028′. Unbelievable. I’ve about had it with this upside down nonsense.
Three basic templates for winter precipitation events this season:
(1) Moisture moving into wedged-in/dammed cold air.
(2) Miller B transfers from inland to coast.
(3) Dynamic cooling changeovers from rain to snow.
This one may have elements of all three. Appropriate.
Sorry do you think we have a chance of accumulating snow this far south
Do you think that this snow will accumulate on the roads? Or mainly on grassy areas? I have to travel around noon on Sunday…..and I hate snow.
Kevin, thoughts on the 18z GFS? I suppose it could be a possibilitly, but there’s hardly any precip at all for us this particular one, granted though it is the 18z, but still. I’m still going with about 3 inches of snow for the roanoke valley, i think the Nam and Euro is overdone and the latest gfs is underdone, but we’ll see.
The WPC indicates most or all of it will be north of Roanoke.
http://www.hpc.ncep.noaa.gov/wwd/day3_psnow_gt_04.gif
Can’t remember if it was yesterday or the day before…but I mentioned I’d feel more comfortable about snow being in PA, western Maryland, or even NW Virginia. The nagging feeling I get is that this storm, despite a favorable late-season setup, will continue the overall winter theme of near misses.
Well, WPC expects most or all of the 4+ snow north of Roanoke. Though the percentages of 1+ have drifted back to coin’s flip.
http://www.wpc.ncep.noaa.gov/pwpf_24hr/prb_24hsnow_ge01_2013032300f048.gif
The Miller B type really works best (to yield snow for us) in mid winter. I may have to revise my depths down one inch, JUST BECAUSE IT’S SO LATE IN THE SEASON. Also, the high to the north that is supposed to wedge in east of the mts., it’s not exactly in the prime location (NE US, St. Lawrence area is better than the current high feeding from north Central US.
This will be a test to see if models still underestimate CAD this late in the season.
18Z NAM is still crazy. Plenty of precip!!
Check out my ustream concerning palm sunday event Live!
ustream.tv/channel/TheMountaineerShow
So as it comes down to the wire, this winter will be remembered as the winter of cold enough air not being present at the right time, the one time it was[Jan.26th], a storm that didn’t have the hindend to do much, and the less than favorable track, blocking, direcrtion of track. Hey!!! that perty much sounds like an atmospheric pattern don’t it. This ain’t the first winter like that tho. Somebody else can sort out when. The big question> when is going to give it up and let the fat lady put on her show?
@2450 Rick: I think these Mets exist for the sole purpose to draw blue and red lines in different places.
I love snow but I’m tired of the “dammed” cold air.
Thanks for letting that through Kev. Stickin’ with the baseball analogies, you lobbed that one in there and nobody else was swingin’, lol. OK, I quit.
Dammed isn’t a bad word last time I checked.
OK, Arctic Oscillation update. Big news there, but it isn’t about the current situation, because as the ensemble predicted yesterday, the AO level remained unchanged today, although the level seems to be either -5.4 or -5.5, not the -5.6 I mentioned “ayer.” The BIG changes in today’s ensemble outlook are:
A. that it will start to climb almost immediately, getting to -3.0 about the 28th and to -2 on the 30th. That is the good news for those of you/us who want this unseasonably cold weather to end. Now for the potentially bad news.
B. All the models showing a “rocket launch” to +2 or +3 in early April (on last night’s graph) have disappeared!! After the AO gets to -2, which is pretty much consensus, the strands divert some, but even the most positive (i.e., “warmest”) ones only take it to +0.5!! Nearly all of them keep the AO in negative territory!! As Kevin and Sean Sublette on WSET-13 have been saying, no end to the continuing cooler than normal weather in sight. Of course maybe the PNA could help out with a negative streak of numbers which would place a ridge over the east, but that is nowhere in the outlooks for that oscillation, either!! Moderately positive PNA for the next two weeks.
Sorry Hope and others. Absolutely no sign of extended warmth from the teletubbies.
Think there will be a WWA posted soon?
I’m looking forward to the nice weather tomorrow…I need to cut up a bunch of tree branches that ripped off the trees during the windiness this winter and haul them off…plus get some more mulch and a couple other things from Lowe’s to get the flower beds prepared for growing season. Still, our daffodils haven’t yet bloomed, and the forsythias, crabapples, and cleveland pears are looking fairly dormant. I bet the first solid stretch of 3 days of 60+ weather gets that changed though.
I did see some neighbor’s daffodils in bloom though, and a couple flowering trees starting to show color along Route 114 though.
How is tomorrow looking now Kevin? I know at one point you thought we may be cloudy and that would hold down temps.
I didn’t mention the NAO (“North Atlantic Oscillation”) but it may be the most depressing of the 3 oscillations looking into the future for any sign of warm weather. It is at -1.1 today, unanimous consensus that it will drop to -2 or at least very close to that number in about 5 days. Then bounce back but only to -1 for the rest of March. After the 31st, one or two red lines do get the NAO to get to neutral, but the majority of models have it sliding MORE negative again, to about -1.5.
Today was not bad at all. Plenty of sunshine and medium temps (mid 40′s) and very little wind!!! Everything I could have wished for. The calm before the storm. Was out and about today and loved every minute of it. Had to chuckle though because the brine trucks were out doing the roads around Christiansburg. I am glad they are preparing early.
Okay- I am ready for a little snow. Bring it on!
Polar view: things are not looking as great any more. In two of the four areas of interest. The one that still looks good is the strength of the vortex centered over Montreal and Quebec City. Still bright blue, no weakening. And the eastern edge of that vortex has another core over the northeastern part of Nova Scotia, which is called Cape Breton Island. This looks VERY promising to become a 50-50 low in the area of Newfoundland.
The less-than-great news for those of you wanting the cold to hang in here: the trough over the eastern USA has weakened. Intermediate green air over South Carolina, and pale green over NC. Lightest shade of blue over SW Virginia. I guess that goes along with the short warm-up that happened today and will continue a tiny bit tomorrow.
The biggest news is that the green air over Greenland is definitely weakening, and the air over the North Pole is pale blue, which is still not as dark a shade as normal, but the green air has moved on.
IM FEELING MY SPINE TELLING ME THAT THERE IS AT LEAST 5 INCHES . DONT NEVER BET AGAINST YOUR SPINE.GET READY ROANOKE!
Cold air is going where theres enough oomph
to get it there…warm air will return when the power
of the suns angle holds sway. Its natures way.
Cold air or inversions be damned or dammed
..What we want as fleas on this scrubby earthscape
matter far less than a dandelion seed looking for a
wet spot.
It will be what it will be..it was before we got here
and my long term forecast says conditions much the same
well after the last sunset.
Newt, would that be Mets or meteorologists? Who is more likely to hit a home run?
Here is a word about tomorrow’s weather. NWS and nearly all forecasters are calling for it to be cloudy here at times with a light west wind. Roanoke high of between 51 and 53 seems to be consensus.
The following is NOT a prediction, but an observation. If the clouds are less prevalent than forecast, and especially if the winds swing to any direction south of due west (even WSW), Roanoke could easily warm up to the upper 50s and maybe even 60 (or even 60+?). Remember last Saturday when the forecasts were for the mid-upper 60s for Roanoke, but the sun really got going and there was a SW wind? Roanoke made them “look like donkeys” with a high of 77
I am not making any link about whatever may happen tomorrow to having a major effect on Sunday. The above is restricted to tomorrow. But I have seen lots of forecasts over the years be way off this time of year when that WSW or SW wind gets going and there is even muted sunshine. Just like March 16th.
Other John, I am now leaning toward your outlook. Not much snow here (2 inches at my house tops), and especially where you live, 40+ miles west of me. Even though the NAM is robust, I think the general trend became a tiny bit less bullish for enough cold for enough hours. Tomorrow’s trends will hopefully tell the full, agreeing story. And of course they could have the GFS and others jump on the NAM train.
A friend was reading an update on WDBJ7′s weatherand it stated to check back frequently on Sunday for updates on the storm. It appears that no one really knows what this storm will do, if anything. Sadly, I wouldn’t mind one more decent snow storm for Botetourt but don’t think we will see it. Happy Birthday Doppler Carol and Nick(hope I didn’t get the date wrong).
Thanks, Erin. All together now, WJN: “Happy Birthday to you two, Happy Birthday to you two ……
Happy Birthday Dear Carol and Nick ……. Happy Birthday to you!!!”
P.S.: “And many more …..”
Erin in Buchanan – nope you got the date right! I got my wish – sunshine and no wind. Now Nick can have his wish for snow – starting tomorrow.
I am thinking the accumulating snow will be north of Roanoke and on up and into the Shenandoah Valley – Not much in the New River Valley. Guess we will just see what happens.
Notes about this non-spring:
My forsythia just set a record (exact date to be determined) for the date of their latest blooming. 3 years ago it was today, March 22nd. Nearly all of the buds are still hibernating, just like Mister Spring.
The first week of Major League Baseball (most teams open on April 1st …… weather permitting, of course) could be littered with postponements, or games that get played but should have been postponed. On 4-6-2007, the Cleveland Indians were supposed to host the Seattle Mariners for four game. All four were postponed by snow and cold. The schedule for both teams was screwed up as a result.
I have only seen two forsythia bushes that are close to full bloom, both in Roanoke city, and both face south and are protected from NW and N winds.
New NAM (0Z) still has pretty heavy snow starting sharply through the middle of the New RIver Valley northeastward, with 6-7 in the Roanoke area. It has nudged northeastward with the snow area, though.
http://raleighwx.americanwx.com/models/nam/00znamsnow_SE060.gif
It does show a secondary area of snow swinging through Sunday night, but most is on the front end during the day.
Yep, the new NAM with 6-7, down from the 9-10 it had for so long.
That’s one run, though, … but we doeth draw closer. (I still don’t give it full credit until it has two runs with the lower amts).
It’s amazing to see the big cutoff to the SW, even the high country NC gets very little. However, the 00Z NAM 4km nest (hi res) isn’t so diminuative down there, with 9+ down I-81, then the spine of the blue ridge in NC. It has 4-7″ for Roanoke county with higher in the south half.
The GFS is too probably to dry, but the higher NAM amount, if real, should get cut down by sleet.
Maybe things will narrow down tomorrow.
Kevin,
Are you thinking more for us in rke?
Right now kinda thinking a couple of sloppy inches for Roanoke. Riding awfully close to that 0C/850 mb line on most of the models. I could see this dancing back and forth between snow, rain and sleet. This may be a case where there are 2-3 inches difference from the valley floor to some of the higher points, even just a couple of hundred feet higher.
Spring snow situations usually bust. Some bust high and some bust low. I very honestly would not be surprised in the least if we got rain mixed with sleet or if we ended up with about 6 inches.
If you want to see snow … turn to ESPN and watch USA vs. Costa Rica in a World Cup qualifier soccer match in Denver. Never seen a soccer match in a snowstorm before. US team should definitely have an advantage over a team from a tropical country in that.
… and yes, that is our possible winter storm affecting Denver.
I was just about to post about the US game. Between that and KU trying hard to lose as a number 1 it’s a good sports night.
GFS still in the 2-4 inch range for Roanoke/part of NRV. Splits it between day and night
http://raleighwx.americanwx.com/models/gfs/00zgfssnowdepth084.gif
Signing off for the night. Will post new on Saturday morning.
That GFS map has my neck of the woods on the nothing to 0.5/1.0″ line/ Seems about right.
34*, mostly cloudy, no wind. Denver is going to have a spectacularly colder than normal day today. High about 25, with snow. Normal high? 54. And I thought it was rare when we were 20+ degrees colder than normal.
A couple interesting obvservations this morning: The NWS forecast for Saturday night through Monday afternoon is forecasting colder temps this morning than it did on Friday evening for the same time frame, BUT it has more rain (and less snow) verbiage in the forecast. What can you make of that – they think it will be colder but with more rain now???? Also, the only counties in VA /WV with any decent shot at significant snow are Highland/Bath — that’s right, the WPC sees a better shot at signigicant snow in Highland/Bath, VA than even Pocahontas, WV. Bizzarre.
NWS showing a nuisance event rather than a significant winter situation (no watches or warnings – yet). National surface map still rather quiet (so I don’t blame them).
Euro is the now lightest amount (1/2″?) Canadian the highest, (both) including the regional GEM with 7 or more.
GFS has been mainly steady lately … about 3-5″, but again, with some melting, and this late, one wonders if the 2-4″ in area is still good.
Going NE of here, it still goes up rapidly (7-9″ up towards Lexington or Staunton way?)
More later.
HPC has us with high freezing rain chances?
I’m really doubting the freezing rain, Brayden, except maybe some patches in 3,000+ elevation areas where it manages to warm aloft. Freezing rain is more difficult to come by in spring, because it’s just difficult to keep a layer of air below freezing at the surface while everything above it is above freezing.
Mike: I just make out confusion. Make a best guess, and adjust advisories/warnings accordingly a couple of hours after the precipitation starts when it becomes more obvious where it’s snowing and where it’s sticking.
Wally: 1/2 to 7 inches is at least a little bit narrower margin on the models than the 0-18 we had for the March 5-6 event.
Clouds ain’t thick but enough to block any sun. Might get to mid 50′s today, but the clouds will have to take a trip. Maybe mid 40′s. 37.9* now and that’s the highest reading shown gor PWS’s on wunderground.
After the winter we have had here in Bedford I am trying to think of how this storm could skip over us. Maybe the primary low would be snow west of the Blue Ridge with rain/snow mix east, then once the coastal low takes over snow bands get to Lynchburg and we are to far west.
With that being said I know we have a lot working against us considering late March climo and this storm being a Miller B, so I will be happy with any accumulation we can get. Going back 35 years the biggest storm I can find this late in the season was March 22&23 1981 when Bedford received 4.5″ of snow while Lynchburg got 3″. That storm put down 9″ in Roanoke and 13″ in Blacksburg.
WOW WE ARE GOING TO GET ONE INCH AGAIN.
WOW, Thomas, you’ve come up in your forecast. You said 1/2 inch a couple days ago.
So Montgomery County looks to get about zero inches…again?
I would say zero to 2 at this point, Derek.
Just posted new blog entry.
I am definitely not expecting anything on the front side of the storm but our forecast is for rain/snow from Sunday Night through Wednesday. That good ole upslope will be cranking for days. Just enough cold to almost empty my woodshed. Guess if I want 70, I can stand by the woodstove.