December Mid-Long Range Discussion

[usedtobe]

I do have a question. If the NAO goes positive as modeled wouldn't it be easy to have the block re-establish itself? If the NAO went positive and the lower heights were spread south and west through Canada then we have big problems because we ridge out down here. But as shown I would think that a +nao isn't a kiss of death nor would it be difficult to get a more favorable look going forward.

I'll take me weenie glasses off now and concede that we're doomed.

Bob, it's not that the NAO is forecast to be positive, it's that there is tremendous differences in handling the higher latitudes, the OA also had a really wide spread. As an optimist, you can take that as being good as even the PNA differs quite a big between members. The problem is that no matter whether the NAO and AO are positive or negative, most of the 500 patterns shown don't look very good for snow, not impossibe but on average not very good.

Plus even to find some that show slight promise you have to look way beyond the 21st, I sure don't see anything before Christmas unless the operation Euro 240 hr is right and then there will be a clipper that will have to go to our south.

[Bob Chill]

Appreciate the insight Wes. I don't think the ul pattern is great either. Not at this point at least but the gfs is consistently showing energy coming into socal after christmas. I never thought we would get snow before christmas except maybe some flakes blowing around with a flurry in cylconic flow once the last in a series of cutters wraps itself up to the N. Euro and gfs both have the same idea for a cold and dry christmas.

The period after that I'm watching post Christmas could easily have a stormtrack back to our west. Blocking isn't looking all that good at this point but honestly, with nothing of significance to track before the cold and dry christmas I can either give up weather watching or hope we sneak something in.

[WinterWxLuvr]

Appreciate the insight Wes. I don't think the ul pattern is great either. Not at this point at least but the gfs is consistently showing energy coming into socal after christmas. I never thought we would get snow before christmas except maybe some flakes blowing around with a flurry in cylconic flow once the last in a series of cutters wraps itself up to the N. Euro and gfs both have the same idea for a cold and dry christmas.

The period after that I'm watching post Christmas could easily have a stormtrack back to our west. Blocking isn't looking all that good at this point but honestly, with nothing of significance to track before the cold and dry christmas I can either give up weather watching or hope we sneak something in.

At the very least a decent cold shot is being consistently modeled within 10 days. If the recent model pattern holds within 36 hours they will probably start spitting out good solutions. Who knows, it may just flip for us and the cold shot might start us down the path. Can't hurt to think positive. Maybe we can get a super streamer off the lakes. Happened here last year.

[WxUSAF]

6z GFS ensemble mean supports the DT storm after Christmas with a s/w tracking to our south with a -EPO/-AO/-NAO and a 50/50 type low.

[Yorkpa25]

I must say the 6z GFS is a thing of beauty in the long range

[WxUSAF]

I must say the 6z GFS is a thing of beauty in the long range

Eh...I don't think the Op is very nice at all. Brings arctic air into Canada, but keeps it locked up there for the most part outside of next weekend's cold shot through Christmas. Every storm is a cutter, absolutely no snow if taken verbatim. Ensemble is a much better look for us.

[brad1551]

As long as we have a -PNA these cutters will take the cake. One day the models show snow then the next day they are gone. I am just thankful it's just the start off winter and it's not mid February without nothing yet. We have lots of time for things to change. Seems like the show will be in the Northeast while the Mid-Atlantic

watches and waits patiently like always. Lol

[brad1551]

All I see in the 6z GFS is cutters!!!

[Bob Chill]

6z shows possible snow to rain on the 26-27th. Surface below freezing at onset and 850's although marginal would support a period of snow. And it's a long ways off. h5 not terrible looking in general. No sense taking anything verbatim. Bottom line is the gfs is consistently showing precip nearby or overhead in the 26-28th time frame and there is a cold airmass in place prior to that. Even with a nw storm track thermal profiles can still produce some front end snow.

[clueless]

6z shows possible snow to rain on the 26-27th. Surface below freezing at onset and 850's although marginal would support a period of snow. And it's a long ways off. h5 not terrible looking in general. No sense taking anything verbatim. Bottom line is the gfs is consistently showing precip nearby or overhead in the 26-28th time frame and there is a cold airmass in place prior to that. Even with a nw storm track thermal profiles can still produce some front end snow.

Whatever it is in that time period, it is not going away yet. It could, and probably will be, a miss for us. We should expect it, 'cause climactic history is not kind to us for Christmas. Something to keep track of in the meantime. We laugh, we cry...so goes MA winters.

[WinterWxLuvr]

6z shows possible snow to rain on the 26-27th. Surface below freezing at onset and 850's although marginal would support a period of snow. And it's a long ways off. h5 not terrible looking in general. No sense taking anything verbatim. Bottom line is the gfs is consistently showing precip nearby or overhead in the 26-28th time frame and there is a cold airmass in place prior to that. Even with a nw storm track thermal profiles can still produce some front end snow.

So far the changes on the GFS by next weekend are pretty big. Don't know the end result yet, but consistency isn't much. I should say, changes from 24 hours ago.

[brad1551]

I am conservative and look for better set-ups then cutters. We might have a chance of snow and I will take it but most of the time lose out and most people know that. When we have a -NAO/-AO/+PNA/-EPO & MJO 1,2,8 I will be a happier in general. Sounds like a lot to be in sync but it will happen this winter. I am not counting on the 24-26 storm until a couple days away from the event.

[WEATHER53]

10-15 days away ghost has begun to haunt, if we get to 12/25 and are talking about 1/5 to 1/10 then we are cooked.

[Bob Chill]

So far the changes on the GFS by next weekend are pretty big. Don't know the end result yet, but consistency isn't much. I should say, changes from 24 hours ago.

Yes and no. Cold shot after the clipper wraps up. Decent period of LES / upslope.

You can't possibly tell me that hr276 isn't interesting. LOL. I refuse to back off my stance that the window exists post xmas.

[Wonderdog]

Yes and no. Cold shot after the clipper wraps up. Decent period of LES / upslope.

You can't possibly tell me that hr276 isn't interesting. LOL. I refuse to back off my stance that the window exists post xmas.

I agree with your assessment. Post Christmas week has looked somewhat promising with more cold air for the last few runs. Frankly, there has been too much hand wringing over our lack of snow in early december when in fact, we hardly get any at that time anyway, which is in line with the mid-atlantic's typical winter season. We all need to get a grip and at least wait until winter officially starts.

[Ian]

I'm not worried much with where we are just yet. But let's not act like March is a reliable winter month for the lowlands. Met winter is more reliable around here. I don't think anyone was planning on much snow by this pt tho a window was supposed to be around now according to some posts over the course of the month... So arguably we are starting to lose out on days of winter.

[WinterWxLuvr]

Yes and no. Cold shot after the clipper wraps up. Decent period of LES / upslope.

You can't possibly tell me that hr276 isn't interesting. LOL. I refuse to back off my stance that the window exists post xmas.

Well, all I said was different. The heights don't deepen nearly as much next weekend and the flow is much flatter afterward. Looks like that might actually help us, keeping storms from cutting. I'm with you on the Christmas storm. Let's hope it works in our favor.

[WinterWxLuvr]

I'm not worried much with where we are just yet. But let's not act like March is a reliable winter month for the lowlands. Met winter is more reliable around here. I don't think anyone was planning on much snow by this pt tho a window was supposed to be around now according to some posts over the course of the month... So arguably we are starting to lose out on days of winter.

I agree. March stinks. If I'm getting snow, I want it from now until about the end of February.

[mattie g]

I'm not worried much with where we are just yet. But let's not act like March is a reliable winter month for the lowlands. Met winter is more reliable around here. I don't think anyone was planning on much snow by this pt tho a window was supposed to be around now according to some posts over the course of the month... So arguably we are starting to lose out on days of winter.

I agree.

I think the concern is more that, while the models in the longer ranges have hinted at good windows here and there, either nothing has come of those or they keep getting pushed back in subsequent model runs. We've seen that play out before, and it doesn't give a good feeling at all.

Of course, all we really need for a decent winter in these parts is a couple fairly small (3-6") events and perhaps a clipper-type event or two and a few extended cold snaps. Those small events can creep up on us at any time during January and the beginning of February without needling a terribly cold look on the models. So while there's no reason to punt winter just yet, it's completely understandable to get a little knot in your stomach as we watch how the pattern is shaping up.

[WVclimo]

Long range models and ensembles have been consistent the last 3-4 days that the cold arrives the end of this week and stays around past Christmas. Today's Euro looks blustery after Thursday. Probably some flakes blowing around next weekend if that verifies.

[mitchnick]

surface temps of 12Z Euro is the freebie of the day

this animation looks pretty good and "reasonably" convincing in light of all modeling the past 3-4 days

no snow, of course, but 1st things 1st I guess

http://www.ecmwf.int/samples/d/animate/catalog/samplers/banner/two_metre_temperature_and_30m_winds!240!North%20America!t2m!pop!od!oper!w_t2m30mw!2012121512!!!step/

[WinterWxLuvr]

Bob, are you secretly running the GFS? You now have us getting a nice snow on Christmas eve and a really good one on boxing day.

This happens and you're the man.

[mitchnick]

Bob, are you secretly running the GFS? You now have us getting a nice snow on Christmas eve and a really good one on boxing day.

This happens and you're the man.

verbatim, don't think the first system would be snow, though close

Boxer day is!

In fact, Boxer day first legit snow on the GFS this winter I think (legit as is GFS is showing a snow storm verbatim)

[clskinsfan]

Yes and no. Cold shot after the clipper wraps up. Decent period of LES / upslope.

You can't possibly tell me that hr276 isn't interesting. LOL. I refuse to back off my stance that the window exists post xmas.

I agree with you. The few days after xmas look to have solid potential. The 500 setup is still good on the models for that time period. But it is a long way out for sure. Optimism is the word for this winter.

[WinterWxLuvr]

verbatim, don't think the first system would be snow, though close

Boxer day is!

In fact, Boxer day first legit snow on the GFS this winter I think (legit as is GFS is showing a snow storm verbatim)

Per the clown map the first is a snow event. Of course, at this range it's almost pointless to talk it up. It is nice to have cold and potential being modeled within a reality range, the former more so than the latter.

[WxUSAF]

This Xmas eve storm on the 18z GFS is sort of out of nowhere, so I wouldn't pay it much mind right now. But, the post-Xmas storm signal is pretty good. GFS and Euro differ in details of course, but both have a signal about the same time, so that's the good thing. What we need to happen this week is have these big cutters create this broad upper low over the GL/Southern Canada that ushers in the arctic air. This will surpress the storm track and keep whatever possible storm after Christmas from cutting west.

[stormtracker]

Yeah, that's a hell of an 18z GFS run, although it's in la la time frame. It's nice to look at. The second one (The Chill Storm) is a nice one and definitely all snow. A whopper all up the coast too.

[Dsnowx53]

This Xmas eve storm on the 18z GFS is sort of out of nowhere, so I wouldn't pay it much mind right now. But, the post-Xmas storm signal is pretty good. GFS and Euro differ in details of course, but both have a signal about the same time, so that's the good thing. What we need to happen this week is have these big cutters create this broad upper low over the GL/Southern Canada that ushers in the arctic air. This will surpress the storm track and keep whatever possible storm after Christmas from cutting west.

The Pacific pattern becomes much improved, too. This is the first time we're really seeing the dual blocking look over Alaska and the west-based NAO regions. Very nice to see.

[WinterWxLuvr]

This Xmas eve storm on the 18z GFS is sort of out of nowhere, so I wouldn't pay it much mind right now. But, the post-Xmas storm signal is pretty good. GFS and Euro differ in details of course, but both have a signal about the same time, so that's the good thing. What we need to happen this week is have these big cutters create this broad upper low over the GL/Southern Canada that ushers in the arctic air. This will surpress the storm track and keep whatever possible storm after Christmas from cutting west.

That broad flat area of low heights is a feature that was showing up at about 10-11 days on earlier GFS runs, but on the last two has shown up at about day 7. The Euro has the low, just a different configuration. You would think it would keep storms from gaining too much latitude too soon, especially if it forms like the GFS has it.

[Bob Chill]

Bob, are you secretly running the GFS? You now have us getting a nice snow on Christmas eve and a really good one on boxing day.

This happens and you're the man.

Heh, looked at the run. Xmas storm is warm at the surface until after the low gets NE of us but 850's and thicknesses are awful close to being pretty good. But the part that is needed to keep in mind is the storm shown on the 27th looks so darn good because of the "out of nowhere" xmas storm. The whole if this then this kinda thing. No storm on the 24-25th and we're right back to worrying about the storm cutting west.

I will say this though, the gfs has been hell bent on some sort of storm between the 26-28th. I've liked the setup ever since it showed up at like hour 500. Get a good ull low to wrap itself up to the north and pull a nice chilly airmass down and then have something chase on it's heels. I've had my eye on it more just because it's been the "only" thing I've seen that looked "ok". Not because I though it looked great or had any type of high prob of occuring.

As Wes has clearly pointed out that the different 500 looks haven't been great or even good except now the 18z is showing a decent vort track for both systems. And they both pull off the gulf.

If this damn thing pans out then I am retiring with a winning record. Another day has gone by and I have zero reason to doubt my hunch....yet...