1800 EST 28 DEC …. STARDATE 201112.28
As somebody who works in his own home office and owns theor own business… I don’t get a lot of days off. Even when the weather in the Middle Atlantic states is fairly quiet there is ALWAYS weather to talk about which I have to cover for energy and grain clients. So the holidays for me is a big slowdown and much needed one. Unless of course you have a major East Coast snowstorm or blizzard like we did last year… In which case it’s a lot of fun but it’s very intense and it’s not really a break.
Even in this relatively quiet in on eventful winter so far across the eastern half of the CONUS I am watching the developing second heat wave of the growing season for Argentina… Another round of flooding rainfall likely for much of eastern and central Brazil… as well weather in Australia and South Africa.. and the winter wheat crop in the Ukraine and sw Russia… and … and … and…
By now mostly you have probably heard about the potential for a significant if not major East Coast snowstorm on January 3-4. On Monday and Tuesday the 0z and 12 runs of of the European model one bonkers with the development of a major storm on are just off the East Coast and a huge amount of snow. The 12z European model on Tuesday 12/27 showed a huge amount of snow — 12 to 18″ in a band from the Virginia North Carolina border all way up the Boston.
I debated about whether not to post this map because I know is going to cause problems one way or the other. But I decided to post a map for number of different reasons. There were 3 primary reasons WHY I decided to issue the European snow map from yesterday.
- as I am sure you and all of your friends and family KNOW …it has been a really mild winter so far especially given the last two winters (which were pretty active if not downright severe the times). So if we were to suddenly see a significant or major East Coast winter storm it could catch a lot of people by surprise.
- The European model yesterday showed a lot of snow not just a few inches… so I wanted people to understand the gravity of the potential significance of the storm if it in fact develops. I suppose some people are going to accuse me of issuing of that snow map from yesterday’s European model in some sort efforts to increase the web site in the face book the viability/ visibility and or Donations… but really that has little to do with it.
- I try not to talk down to people if I can avoid it. That’s not to say I won’t rip somebody in new body cavity if they deserve it. I certainly will do that I think I need to. But when I issued the European snow map from yesterday’s model run I stated quite clearly that this was NOT a forecast of some of projection. For the most part most people understand what I am talking about. If you are stupid you probably shouldn’t be on the Internet anyway and decides the great thing about stupid people is that it gives me an opportunity to crap on them. I could have played it safe and not issued the map because I know that it would cause some confusion… But quite frankly the culture is stupid enough as it is and I rather not be a part of that since I am supposed to be a scientist and not a game show host.
Of course once I issued the snow map I guess it was inevitable that the model data early on Wednesday morning and on Wednesday afternoon would turn the other direction and shift the potential major East coast Low further off the coast ( to the east). Given that this event is still 6 or 7 days away I don’t consider this sort of model shift or variation to be of any significance. The important thing is that the system is still there on all the weather models.
On the other hand it should be kept in mind that this is NOTHING like the last two winters. Over the last two winters the pattern set up early and locked in and a really did not change until spring or late February. In the winter of 2009-10 and 2010-11 if you farted too loudly it would might cause and East Coast snowstorm to develop. That is certainly not the case so far this winter.
I have been asked a number of times to comment with regard to the debate as to whether not the pattern NEEDS to have a -NAO to a East coast snowstorm. Like many things in life there are several nuances to this question.
If the question is does there “need” to be a -NAO for any accumulating snow in the Northeast ( VA to MAINE) then the answer is clearly no. We certainly can get accumulating snow of the few inches with a +NAO.
But IF the question is does there NEED ( required) to have a -NAO to have S.E.C..S (significant East Coast snowstorm) a M.E.C.S. (major East Coast snowstorm) or H.E.C.S. (historic East Coast snow storm) then the answer is yes you do need one 9 times out of 10.
For example if we take a look at the OCT 29-30 NOREASTER that dropped the historic early season snowfall over the higher terrain of the northeast and caused tremendous damage in places such as interior Connecticut and western and Central Massachusetts… we can a very clearly see a defined -NAO and a clearly defined 50/50 Low as well.
Without those two features the October 29-30 NOREASTER would have come much further inland. Indeed that has been the problem with all the potential Low pressure area systems so far this winter coming out of the Midwest. The AO and NAO have both been consistently positive and the times extremely positive almost off the chart… So Low pressure systems coming out of Midwest have tracked up either through the eastern Great Lakes OR up the spine of the Appalachian Mts.
Indeed this chart shows the actual status of the AO and the NAO since September 30. As you can see only TWICE in the last 90 days has either the Arctic oscillation or the North American oscillation dropped below zero and a negative territory. And one of those two times …in late October ..allowed the historic NOREASTER to develop with the inland heavy snow.
In this next image we can take a look of the day 9 European vs. the GFS from 12/26… Valid for January 5. The map and less hand side is the European the map of the right hand side is the GFS.
Clearly these two maps do NOT match as the European model is showing a major trough on the East Coast and the GFS to showing a huge ridge covering the entire country. But as we can see now from the current GFS model …. here we are just two days later and suddenly the GFS has a monster trough on the East Coast with all sorts of arctic air coming south covering all the Midwest and northeast and pushing into the Deep South .
If we keep this sort of model failure by the GFS in mind… Then if the 12z gfs model today has no storm near the East Coast I have to allow for the possibility given the poor performance of the model over the past 48 hours …..that the GFS is probably not handling the situation for January 3 correctly.
That being said the European model also is further East off the coast
as is the 12z Wednesday Canadian.
But again as it mentioned above at this point in time the issue is whether not this low was still there at all. And the system is still clearly there.
What about the + NAO? Well that’s a good point. As I stated above if you want to have a really big east coast of snowstorm one needs to have either the AO and / or the NAO in negative territory or at least very close to neutral .
Interestingly as these charts from DR Ryan Mauve’s fabulous website shows the NAO and the NAO do actually dropped very close to neutral early in January at the time of this potentially east coast Low. It is still possible though unlikely that the NAO MIGHT drop into -NAO … Just barely into negative territory– as we saw in OCT 28-29.
Regardless of whether not the East Coast snowstorm actually develops or whether it stays out to sea the interaction between the large cold High coming down from Canada and the coastal Low… will produce a strong and prolong lengthy North wind from Quebec Canada down to Georgia JAN 3-4. The cold air that gets pull down because of depth of the trough and the strong North winds is going to shock a lot of people. The coldest morning the East Coast will depend on whether not there is an East Coast storm so it might be January 4 or January 5 once the winds drop off . I would not be all be surprised to see a lot of temperature readings in the single digits from Virginia up into the big cities of the northeast.
Taking a step further out … we are beginning to see some signs that the pattern may be changing a little bit. Right now everybody and his mom has January as a blowtorch but if you look at the 11 to 15 day GFS and European ensemble means they are not that warmed east the Mississippi River.
The European and the European ensemble at day 10… show the development of a strong ridge over Central Asia that pushes its way northward across the Arctic circle and into and over the North Pole by day 10. The 12z GFS ensemble has this as well.
These image Here SHOW how the BULGE in the Jet stream over central Siberia Builds into the Arctic very rapidly and strongly Day 5 to day 10.
This feature does several things. First it forces the polar vortex to split apart into different sections which in turn weakens the very strong and persistent +AO. If this projection of higher heights were to push into Greenland for example it could cause entire pattern to rapidly shift around.
Indeed if you look at these MECS images you will see a persistent downward trend on all the models with regard to the AO and NAO over the next two weeks. It’s a slow steady drop not a massive swing or oscillation which is one of the reasons why it’s probably going to be the correct overall trend.