A glistening frost on this cold November morning, but was last night a cold weather warning?
Guest blogger Kathryn Prociv stands in while Kevin is away for a few days:
BRR this morning was cold! Saw multiple reports of temperatures dipping into the teens early this morning as well reports of heavy frost covering grassy surfaces and vehicles. With dry air and high pressure in place, we warm up nicely gaining nearly 20-30 degrees by this afternoon; expect highs in the upper 40s to low 50s across the area. Throughout the day as the winds turn east to southeast there will be an increase in cloud cover that will continue into the overnight hours. Thanks to this cloud cover our overnight lows won’t get as cold as last night so expect widespread low 30s (but less spots in the 20s). Tomorrow morning looks somewhat tricky with precipitation moving into areas south and southwest of Roanoke, near the NC border. The models differ on how far north this precipitation will advance, but the real kink in the armor is the Blacksburg National Weather Service office mentions the possibility of some isolated and light freezing rain in the early morning near sunrise. It won’t last long, but could pose a hazard for those isolated spots that see some. By mid-morning most of the precipitation has ended for the southern areas and we’ll move into a partly to mostly cloudy day with highs hovering right around 50 degrees.
So what’s in store for our holiday and travel week? There’s still some chatter about the possible nor’easter, and the Hydrometeorological Prediction Center in the forecasted precipitation map shows a coastal low developing along the Carolinas. However, increasing model trends are swinging this low east out to sea as it moves up the coast. I shared the GFS model yesterday, so thought I’d share the EURO (ECMWF) model today showing a weak low off the coast of Virginia on Tuesday evening. The models continue to show it will be too warm for a snow event. If these model trends continue, coastal areas of Virginia could see some rain and wind, but impacts will be few and far between for us folks in southwest Virginia. We could see a cool and cloudy start to week, and even the return to some wedge-weather but the heaviest precipitation will stay well off to our east.
After this warm nor’easter (if it pans out) what comes next? There’s talk of another storm system in the fantasy-cast forming after Thanksgiving, but how strong will it be and will it be a big snow machine? (In an article Kevin shared with me, he discusses the influence the Siberian snowpack can have on the intrusions of cold air in our area and potential snow events.) When looking at other possible storm systems coming down the pipeline there are multiple factors we must take into account such as the Siberian snowpack, global teleconnections such as the NAO and AO (which Kevin addresses), storm tracks, and how they all line up. The key is whether cold air coexists and matches up with a moist storm system to produce the snow that everyone either loves or hates and forecasting that beyond next week is just too difficult.
I want to thank Kevin Myatt and the Roanoke Times for inviting me back to write for the Weather Journal blog and would also like to thank you all for the warm welcome and great discussion as always. Safe travels and a happy holiday season to all!
November 14, 2012 - 12:31 PM
RSS feed 
Always welcome.
Strongly concur with Kathryn about how next week’s nor’easter doesn’t look like it wants to tap the deep Arctic air, at least so far on the models.
Why the deeper cold air isn’t penetrating on the models is pretty obvious upon further review (my first in about 5 days)… persistent low-pressure in the eastern Pacific/NW U.S/Canada region. That keeps a steady west to southwest flow of wind across much of the country, largely counteracting the North Atlantic blocking that tries to set up. Check out the PNA (Pacific-North America) index and see how it remains steadily in negative territory, which supports this NW U.S. low.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/pna.sprd2.gif
PNA- combined with NAO- isn’t conducive for classic winter storms or long-term cold shorts in our area. Later in the season, with colder air available, we could get some overrunning moisture into cold-air damming setups — often snow changing to mix. Looks like for now there’s just going to be too much Pacific air to let the Arctic air take firm hold. We’ll get some cold, clammy days but probably not much in the way of wintry precipitation.
12Z Euro now also going farther offshore with next week’s storm. If that sticks, much less impact for anyone on the East Coast with the storm.
Welcome back Kevin. Thanks KP for another great job. Looks to be a relatively quiet travel week for Thanksgiving if the models don’t do a 180 degree turn between now and next Thursday. In a moment of sheer stupidity I picked late November as my 1st snow, so I am really hoping that 2nd fantasy storm becomes a reality.
Keep the faith. Remember 1950.
1950, wd? Didn’t you intend to type 1960? Or did something big happen in 1950 also?
He’s talking about the Appalachian Storm of 1950, Doug. Late November (day aftern Thanksgiving) heavy snow in SW Virgina. Much heavier in Ky/WVa/Ohio.
OK, link time. I think I will (attempt to) post the links to the GFS outlooks for both the NAO and the AO first, then go to some yakking in a separate comment.
Link to the GFS NAO outlooks: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index_mrf.shtml
And to the GFS AO outlooks: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_mrf.shtml
If the PNA flips by month’s end it could get cold and wintry really fast, looking at those AO/NAO charts Doug posted. If not, still probably cold, maybe some wintry precipitation, probably not a major storm … but sometimes there are outliers.
AHHH! Thanks, KM, and also you, wd. That one was so long ago that even I don’t remember it. I would have needed a “womb with a view;” I was born about 7 months after that, July 5, 1951.
47/28 and 43/22 high/low for Roanoke/Blacksburg, respectively, today very similar to mid-late January normals. Daily average temperature 11 below normal at both sites.
Back to the GFS outlooks. If you click on the one for the AO (Arctic Oscillation, in case there is anyone out there not yet familiar with the acronym soup we throw around here), you can see that it has been quite positive for about a week. Now look at the last few days of the 10-day and especially the 14-day outlook. Like a submarine captain yelling an urgent order, it’s “DIVE … DIVE … DIVE!!”
Pair that up with the 14-day NAO graph, which also now shows a fairly long-lasting (more than a week) dive into negative country, and if the negative PNA relents, the last 4-5 days of November (the week after Thanksgiving) could be very cold indeed. Snowy? Foot of snow along the coast? More than an inch in both Roanoke and Blacksburg? Ecstatic COLC whose wife picked NOV 28 as the first snow date?? Stay tuned ….
For your listening enjoyment Mr. Griggs.
http://ww2.ohiohistory.org/etcetera/exhibits/swio/pages/content/1950_thanksgivingStorm.htm
I didn’t enter the snow prediction contest but am thinking Dec. 1 looks like a good day for snow. I also have a feeling that snow might happen in the Dec. 19-21 time frame – that is just an old teacher feeling. LOL! I was volunteering at my granddaughter’s school and noticed at lunch how noisy it was in the cafeteria more so than usual. (Kids always seem to get more active and noisy prior to snow – in my experience. Now Kevin throws out that little tidbit about freezing rain south of Roanoke for in the morning. Hmmmm?
Already 34 as the sun disappears. Going to be a chilly one tonight.
If we get a PNA+ to go along with that AO- and NAO-, as shown on CPC models, I’d give you a 2 in 3 chance of measurable snow in both Blacksburg and Roanoke by Dec. 10.
Doppler Carol: Kathryn and the NWS threw in the tidbit about possible freezing rain with a shortwave along/south of the NC border. Can’t take credit for others.
82 degrees when we landed tonight at 1 am. High tomorrow mid 90s as we visit the worlds tallest building,the Burj.
Thanks, wd. If I had been alive, that definitely would have been the biggest Thanksgiving-time snowstorm I have ever seen. I could not figure out how to turn on the volume, if there was any in the tiny video window.
Hey, Doppler Carol, I just googled the “Burj,” which is in Dubai, and it has the same elevation as you!!! About 2700+ feet!! Should we start calling you “Burj Carol??” LOL
Doppler Carol if it makes you feel any better it looks like the freezing rain probability has backed down some. May be combined to the highest elevations closer to North Carolina.
Jp, you made an interesting comment about 10:30 yesterday morning about daily normals. I disagree with lots of what you stated. I think that the normal highs and lows provide a lot of useful info. If one is looking ahead to a particular city/location and a particular date, by knowing the “normals” one can roughly guess that the highs and lows are “likely” to be within 10 degrees of the two.
They provide a benchmark, which indicate that the odds are 50-50 that the actual weather will be warmer or colder than those temps. Just look at what has been happening in SW Virginia for the last 16-17 days!! Except for about 3 days over this past weekend, we have been incredibly cold, and we know that because of the daily normals for Bluefield, Blacksburg, and Roanoke. By the way, and the following numbers do not include today’s much colder than normal temps, ROA is about 3.6 degrees colder than normal, and Blacksburg is 5.1 degrees colder than normal, which is really impressive to me, because I/we know that Bburg is about 4 degrees colder than Roanoke on average. If we were from an another area and were not familiar with the weather around here, and if we did not have the daily normal temps, we might not know how unseasonably cold it has been lately.
Also, individual days or even stretches of days can be unseasonably warm or cold, but I have found that the number of times in a year that a high temp (for example) is 20 or more degrees warmer or colder than the normal high is very low, probably 5 or fewer times per year. I think we had one recently on a Monday, when ROA’s high was only 41 and the normal high was still in the low 60s.
All I will add about Jp’s suggestion not to use climate normals is to ask what would we replace it with to provide some benchmark of what is expected for a given day. Granted, climate normals are not statistically perfect, but what else would we use?
Mr. Griggs, did you not click the sound button?
It is already down to 28 up here on the ridge. Sky is more overcast and we can only see a few stars. So maybe there won’t be a lot of frost tonight.
I would rather see snow then ice any day so I guess it is good that they are backing off of the chance of freezing rain for in the morning.
Elevation in my backyard – 2546 ft. Elevation at the base of the Doppler is 2800+ ft.
I am a snow lover but I want you to keep that snow away next Wednesday – Sunday (feel free to bring it on Sunday night) and December 20 – January 7!! (I am a teacher and these are our breaks which = traveling for me!) If only there were a way to guarantee that. LOL.
Wow, just read today’s Weather Journal article. Egads!! Looks very much like this winter will be like that winter of 2009-10, when the NAO had a run of something like 16 consecutive months in negative territory. This winter will definitely be a struggle between two differing precedents. On the one hand, the tiny Arctic sea ice and the huge Siberian ice pack spell another huge winter, like 2009-10. On the other hand, obviously this November will be a very negative NAO level overall, which almost always has spelled a big turnaround in the NAO to positive, sometimes (but rarely) in December, often in January, and just about always by February (like 2011).
Wishful thinking has me betting on the big flip. …… But the science definitely looks like it will trump the history of the NOV neg. NAO.
Yeah Doug, DT loves talking about the Siberian snow pack and how if its well established during the fall then winters in the eastern USA tend to be doozies. Kevin, any information of how deep and big an area the snowpack is up in Siberia and what is your feelings about the situation?
It’s the 3rd fastest snow expanse on record in Siberia, Jared, similar to 1976 (before extremely cold winter) and 2009 (before the snow piles).
http://www.roanoke.com/weather/wb/316684
It could be an indicator of a cold and/or snowy winter somewhere — not absolutely certain it will be such for us. But does increase the odds, historically.
Friends of the weather journal, could someone recommend a brand name for a reliable home weather station. I’ll choose the model once I decide the brand. I’ll take any advice anyone has to offer. Is Ambient any good?, La Crosse?, Oregon Scientific? Any help is appreciated.
Kevin, I highly recommend another one of your threads that includes the map of the polar regions with the locations of the polar vortex/vortices in purple. A picture is worth a thousand words. I bet most of them are on the North American side of the North Pole right now, unlike my dream winter of 2011-12.
The CPC is definitely not on board for the upcoming cold winter. I just looked at their outlooks for the NOV-DEC-JAN and DEC-JAN-FEB periods, and the only part of the nation that they are forecasting to have an above normal chance of colder than normal temps is Florida. The amount of solace that I take from that? Zero. I have seen their maps be way, way off in the past many times.
Dopp Carol – I picked Dec. 21 as the first snow date….mainly because Virginia Tech’s commencement is that day and I am remembering we got the big snow in Dec. 18, 2009 on fall commencement day. No scientific guessing on that at all – more like what date would cause the most havoc here. Our commencements, fall or spring, seem to be weather magnets.
I’ve got 31 here and ready to turn in for the night.
Here’s what you’re looking for Doug, courtesy of Allen Huffman’s models page, the temperature anomaly map from the initialization of the 12Z Euro:
http://raleighwx.americanwx.com/models/euro/12zeuro500mbHeightAnomalyNH000.gif
Coldest air relative to normal is right over the pole. Lots of blocky highs around cutoff lows. Looks like the NAO- right now is a little bit east-based — the high not smack on Greenland, but more south and east. That’s usually less conducive to extreme cold or winter storms that parking the high more over Greenland.
I just looked at CPC’s 6-10 day and 8-14 day maps, too. And I don’t believe them, either; especially the 8-14 day. We are in the neutral zone on the 8-14 day. I bet that most of the days from NOV 22-28 are colder than normal, with some being very cold. This is another time that I hope that I am wrong.
Thanks very much, Kevin. That is one WEIRD-LOOKING polar map. Lots of purples, but lots of yellows and oranges signifying warmth, too. I can barely make out the outline of CONUS, but cannot find Greenland.
Map of atmospheric heights actually shows more of the blue colors over on Siberia’s side of the globe, Doug. This is based on atmospheric thicknesses — troposphere is shallower with cold air, higher with warm air — rather than departure of temperatures from normal.
http://raleighwx.americanwx.com/models/euro/12zeuro500mbHGHTNH000.gif
Todd, if the price isnt to bad I would purchase a davis vantage vue or davis vantage pro 2. I have the vantage pro2 and its awesome and u can add many accessorys to it. Predicts weather very well.
Ahhh, the map that appears in the link of your 11:36 comment is the one I had in mind, I guess. Meanwhile, it is 29 starry degrees here.
Hey, Ken in Marion and Rick (of Wytheville), guess which towns are tied with Pearisburg for the warmest forecasted high temps today, according to Leo H of WDBJ7?? Marion and Wytheville at 52*!!! Blacksburg and Roanoke expected to get to only 49. Even Southside locations like Martinsville and Danville only expected to reach 50, probably because of the cool, wet blob in North Carolina that will brush that area.
However, we have yet another “Disagreement Day” between “7″ and TWC for Roanoke’s high temp. TWC thinks it will get to 53 here.
Todd, I have the Ambient WS 1090. I have been thoroughly pleased with it. A good wireless station from the post to the house with all compenents at the station location wired together. And reasonable in price. Probably the best for home use is the Davis Vantage Pro, but that comes at a higher cost. This is my 3rd station. The first I don’t even remember what it was, besides junk. The second, a LaCrosse, I sent back. If you want to go to wunderground weather site then scroll down to the bottom, you’ll see Personal Weather Stations. Mine is KVAROAN020. This will show you what you will get. Ask anything you have questions about and I’ll try to get an answer.
I think the overnight cloud cover prevented the lows from going into the teens. It is 20 this morning up on the ridge. Another chilly, calm, frosty morning.
I’ll plan to post something new this evening. For now, will let KP’s last post sit another day.
For Todd…I have an original Davis Vantage Pro I that I have got about 6 years but is about to be retired(the solar charge is starting to fail and will be problematic in the winter). If I remember right, Quags has a Davis Vue. Any of the Davis products are quality but at a price premium. Range, material quality, and update speed resolution are all factors to consider.
I am evaluating myself and looking at the Ambient 2080 with a second console so I can plug into an IP weather server. My early New Years resolution is to get my weather station data online!!
Weather station list from Ambient with some decent prices:
http://www.ambientweather.com/peorhowest.html
Paul, weather underground offers a deal and puts it on their site free. My Ambient had a deal where they gave you a years subscription to wunderground [10.00 dea] and wunderground is worldwide on PWS. Wunderground is free but costs $10.00 for the upgraded package.
Todd, here’s the one I have but at half the price I paid. This one is a steal. Explains what you get from wunderground also. Everything but the batteries. Also you can download Culumus free.
http://www.ambientweather.com/amws1090.html
Kevin~ Everyone’s talking about our first snow, the NAO, and El Nino….but what this boy want’s to know is when are we gonna get our first round of SNEET and SNIZZLE! I long await for that wedgy delight!!
No sneet or snizzle to go with your turkey and cranberry sauce, it looks like. Beyond that, who knows. More in new blog post soon.