Greenland Block = Brutal Cold on Monday

>> Tuesday, December 07, 2010

Lows This Morning: Talk about a BITTERLY COLD shot of air for Early December! Just as Matt forecasted and blogged about, towns hit rock bottom this morning as arctic air settled into the Charlotte area and the Triad. Somebody call that dude named Gore because temperatures were nearly 20-degrees below normal today! Here's a rundown of how cold temperatures were this morning:

Charlotte: 16

Hickory: 16

Asheville: 16

Winston-Salem: 19

Greensboro: 20

Starting Colder Wednesday Morning: As I write this (7:45ET), winds are calming a bit around the Charlotte area. Winds dying down overnight combined with a clear sky sets up the perfect situation for more cold temperatures. I expect lows to range from 12 to 16 in most areas tomorrow morning as more dry air downslopes off of Mountains in Western North Carolina. With more sunshine and less wind tomorrow, highs may actually reach the upper 30s, but then again maybe not! Middle-upper 30s under a good bit of sunshine is a good bet in many towns.

Strong Weekend Storm, Then Stronger Shot of Arctic Air: Over the past few days, the focus has not only been on the present cold snap, but also a strong storm system poised to move in this weekend. For a time last week, some analysis had shown the upper-level energy diving into the southeast and spawning a coastal area of low pressure (out east of Chaleston). That's when the rumors of snow began, but those hopes ended fairly quickly in all areas outside of the high terrain in Western North Carolina once the GFS and European locked into agreement on more of a TN Valley to Ohio Valley storm track in the direction of the Great Lakes.

The first map below was pulled from today's 12Z run of the GFS forecast model. As stated on the image, this shows a projection of conditions for Sunday evening at 7PM. Beofre I get started on the cold, I do want to point out that there is a possibility of some severe storms Sunday morning given the position of the low and wind shear produced by the strength of the low. On the the cold air though... at 7PM on Sunday, a line of showers/possible thunderstorms will have already pushed through the Charlotte area with very cold air behind the rain. The 0C/freezing line at 5,000ft is projected to be east of Charlotte at that point as northwest winds kick up.

The second map projects conditions 12-hours later (7AM Monday). At that point, it won't be all that fun to be outside! Very cold northwest winds will likely be howling. More arctic air will settle in Monday and it will be VERY INTERESTING to note highs on Monday... may not warm much past of the lower 30s! The ridgetops northwest of Asheville are going to have to deal with more accumulating snow, although tough to tell on accumulations at this point. Also, I have a sneaky feeling that parts of the Western North Carolina Mountains will go under a Blizzard Warning for winds higher than 35mph along with that snow. It will be interesting to watch conditons play out up there as well!

The last map I have posted shows a comparison of the GFS and European forecast models at the same time - next Tuesday at 7AM. Both models are in good agreement of the overall setup. Both show a very sharp trough and brutally cold air for early December! Both also show a persistent Greenland block - strong ridge of high pressure nosing into eastern Canada. This is helping keep fresh supplies of arctic air moving south. Also, as I mentioned earlier, a relatively weak ridge near the west coast looks as if it will remain in place for early next week. If that ridge along the west coast were more amplified, it might be scary how cold things would be around here!

I will try to post a snow-cover somparison tomorrow... hope everyone is able to stay warm!


Anonymous 10:01 PM  

Any snow during our cold snap (s)?

Anonymous 2:09 PM  

If you want snow, do not look at the GFS past day 8! It is handling storms and cold air horribly and I think it is unusable. There is way too much blocking as we get into Day 9 through 16 to be a zonal flow. I think we have more chances for snow between now and Christmas.

Gastonwxman 6:12 PM  

Just thought I point this out: Some of the modeling has trended pretty far south with our next storm system. A few models, like the UKMET, now shows what could be a setup where we have rain for a moment that kicks over to snow as the low goes back up the coast. It just showed up for today, so it can easily change, but our December 12-13 storm just got more interesting. Too early for accumulation calls, of course.

Chris Enloe 6:49 PM  

@Killer, I think that we are going to sneak maybe 1-3 maybe 2-4 inches out of this system. It of course wont be snowing in the daylight hours on Sunday, but when the sun goes down I think that is when we will see a change-over. The models are showing another 12-15 hours of precip after 7 p.m. Sunday night, so I think that will see some snow.

jtomlinwx 6:26 AM  

CHeck Out my Blog at...
I talk all about it!

Andy Wood 10:08 PM  

hey guys, been busy over in Greenville and haven't had a chance to answer any of your Qs... will have a post up about the chance for snow a bit later (around 11ET)

Gastonwxman 10:12 PM  

0z NAM is rather interesting. In addition to a couple of other models (one of them being the Ensemble members of 18z GFS), 0z NAM also pops what appears to be a secondary low somewhere in MS. This low slows and deepens as it continues on an eastward trek and then turning NE toward the NC coast. This did not show on other modeling until recently. It MAY help pull down colder air, which is why places like Atlanta are now seeing a slightly higher chance of snow from Sunday night-Monday morning. We shall see if the OP models and other Ensembles follow this.

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