SE Mid-Long Range Discussion II

[packbacker]

But how well will the cold air be set up?

It would be very iffy for anything east of Greensboro, but if there is a SLP off the coast of NC and precip can make it back to INT or GSO and points NW that it would be frozen. It's a long shot, we just need the piece of energy coming into the west coast in roughly 36 hours to not leave the energy behind which develops into a closed low off the coast of CA. So there is still time for things to change but it's a long shot.

0z run, doesn't leave anything back and we get some action for the east coast....

18z run, leaves it back...

[packbacker]

Agreed, since OP didn't have it...I count 5 of 11 members that look interesting, the others do not. There are also a few that go with the OP, no low. IMO that discredits the ones that show it.

Yeah it's not very likely considering what decides this (see post above) happens in less than 48 hours.

[packbacker]

Agreed, since OP didn't have it...I count 5 of 11 members that look interesting, the others do not. There are also a few that go with the OP, no low. IMO that discredits the ones that show it.

If this opportunity doesn't hit next weekend than we are looking at at least another 10 days for another shot, probably closer to the 20th.

[Jon]

If this opportunity doesn't hit next weekend than we are looking at at least another 10 days for another shot, probably closer to the 20th.

I agree with this...I'm reluctant to say I like what I see 200+ hours out more than I do <200 hours out, because that's usually how it is, fantasy. But I truly believe after seeing the disco that once we get into mid to late Jan early Feb things will start going our way. We need a few close calls with difficult to almost impossible setups like this weekend before we get the real deal.

[packbacker]

I agree with this...I'm reluctant to say I like what I see 200+ hours out more than I do <200 hours out, because that's usually how it is, fantasy. But I truly believe after seeing the disco that once we get into mid to late Jan early Feb things will start going our way. We need a few close calls with difficult to almost impossible setups like this weekend before we get the real deal.

Agreed. I do feel like we will get some snow, a 3-5" will feel Iike a blizzard. With the record AO we saw in December plus a constant positive NAO plus this gosh darn La Nina to get a few inches a snow would be quite the feat.

[dsaur]

18z looked a lot like the 12z GFS. Cold air then it moderates and hints at some winter weather only to get too warm and weaken the system. however there is a big fantasy storm at 372.

I wouldn't be surprised to see Goofy bring back the week end storm. Have to see how accurate it is in the near term with the next few days rains. So far it has been right with the present rains. It said I'd get a pitance, and that's what I've gotten so far It wants to give me a good dose midweek, we'll see how that verifies. Tony

[FoothillsNC]

Agreed. I do feel like we will get some snow, a 3-5" will feel Iike a blizzard. With the record AO we saw in December plus a constant positive NAO plus this gosh darn La Nina to get a few inches a snow would be quite the feat.

The NAO is heading down and get close to neutral, and the AO is down as well. When there is polar blocking like forecast to occur eventually, most likely both signs will go negative. Theres plenty of Nina's that produce snow in the Southeast, esp. NC.

The key here is plenty of patience and waiting on double blocking to change things up.

[packbacker]

The NAO is heading down and get close to neutral, and the AO is down as well. When there is polar blocking like forecast to occur eventually, most likely both signs will go negative. Theres plenty of Nina's that produce snow in the Southeast, esp. NC.

The key here is plenty of patience and waiting on double blocking to change things up.

It will be fun to see this develop and see what fun can be had...

[FoothillsNC]

It will be fun to see this develop and see what fun can be had...

I've studied a lot of blocking but don't recall any that has this look really. It's quite anomalous and the models are going to go through fits the next few days. But I'd say the Alaskan block combined with West Europe/Scandi block would lead to depressed flow in the US. With a supressed, split flow eminating from the Pacific. The vortex in Canada should rotate spokes of cold air into the US, as opposed to drop a tremendous load all at once. This would favor a very active and cold U.S. A potent southern wave or opening cut-off that remains supressed could be an ice/snow maker.

[griteater]

Regarding the 6+ day range, one of the trends I've noticed over the past day or 2 is that the building vortex in NE Canada is being modeled stronger (lower heights). Now, that would not be a good thing if we didn't have any high-latititude blocking developing to the west/north/east of that vortex since that would increase the flow in the NAO region, and would prohibit formation of a -NAO block. However, if we can get blocking to the NW of the vortex (Alaska ridge) and/or to the NE of the vortex (Scandinavian ridge), this will act to displace the vortex to the south....and the stronger this vortex gets, the less we will require for it to be displaced south since a stronger vortex will be capable of supporting a more expansive cold dome. If you look at the hr216-240 frames from the 12z Euro, you can see the ridging to the NW and NE of the vortex pushing it south. At 240, you've got a 1037 MB high in North Dakota with the 500mb vortex to it's north edging south. It's a very, very good looking setup. The big questions obviously are...where exactly does the blocking setup, how strong is it, and does it hold (or is it transient).

[Met1985]

Regarding the 6+ day range, one of the trends I've noticed over the past day or 2 is that the building vortex in NE Canada is being modeled stronger (lower heights). Now, that would not be a good thing if we didn't have any high-latititude blocking developing to the west/north/east of that vortex since that would increase the flow in the NAO region, and would prohibit formation of a -NAO block. However, if we can get blocking to the NW of the vortex (Alaska ridge) and/or to the NE of the vortex (Scandinavian ridge), this will act to displace the vortex to the south....and the stronger this vortex gets, the less we will require for it to be displaced south since a stronger vortex will be capable of supporting a more expansive cold dome. If you look at the hr216-240 frames from the 12z Euro, you can see the ridging to the NW and NE of the vortex pushing it south. At 240, you've got a 1037 MB high in North Dakota with the 500mb vortex to it's north edging south. It's a very, very good looking setup. The big questions obviously are...where exactly does the blocking setup, how strong is it, and does it hold (or is it transient).

Good post. I have noticed that soem of the models try to really bring down the PV just north onf the US/Canada boarder. Hope it stayes were it just breaks off pieces of cold air and does not suppress the flow to far south.

[packbacker]

Quite a rainy next few days...

[packbacker]

GFS close to popping a low at 102

[NCSNOW]

Has a decent upslope from 96-102: Not gonna be playing golf next weekend:

[LithiaWx]

Where is the gfs analysis?

It's not good from a surface perspective. Most of us get good rains from the ULL then it gets pretty cool, probably some upslope snow with the cold shot. Then it warms back up again. No snow outside the upslope. out to 300.

[Met1985]

Looking at the GFS so far, it still looks very cold maybe colder this run than last especailly for this weekend.Ya looking out pas this weekend does not look that cold but just one run.

[packbacker]

Not bad, keeps the ridge out west almost the entire run, just no activity shown, hopefully that changes. In the long run, it still looks OK, to me.

[Met1985]

Ya like is has been said time to time the models will change about evey run. I am concerned with this front swinging through at the end of this week than the long range. Looks like we could see a pretty good upslope event.

[griteater]

Heck of a source region for cold air damming

-36C at 850mb just north of the U.S. border

[griteater]

Here's the UKMet at the beginning (06hr) and end (144hr) of its run. You can see how all the cold air is bottled up around the north pole in the first image (dark purple showing low heights). Then at 144hr, the low heights are split up into a few pieces. Also, the ridge is going up through AK, which is better than the 00z GFS op's placement west of AK.

[JoMo]

The differences between the GFS and Euro are almost comical.

GFS @ 216

Euro @ 216

The Canada maps are even more impressive with Canada in the ice box on the Euro.

[HKY_WX]

Day 7 looks interesting on plymouth for the euro. Potential overrunning setup day 8 and 9. Of course i am extrapolating. Need to see the frames to confirm.

[griteater]

00z Euro sqashes the Scandinavian ridge (similar to the look of the 12z Euro Ens), so we're left with the ridging going up NW of Alaska (although it does bridge with ridging across the pole in central Asia). The result is that the strong polar vortex in N Canada does sag south to the north side of Hudson Bay....but who knows what happens from there. We have a tremendous supply of cold air on the doorstep of the U.S. in southern Canada....but does it retreat or get displaced south. If the western ridge goes up NW of Alaska, we really need addtional ridging on the Scandinavian side to get the cold air to head farther south.

[Met1985]

00z Euro sqashes the Scandinavian ridge, so we're left with the ridging going up NW of Alaska (although it does bridge with ridging across the pole in central Asia). The result is that the strong polar vortex in N Canada does sag south to the north side of Hudson Bay....but who knows what happens from there. We have a tremendous supply of cold air on the doorstep of the U.S. in southern Canada....but does it retreat or get displaced south. If the western ridge goes up NW of Alaska, we really need addtional ridging on the Scandinavian side to get the cold air to head farther south.

I noticed on the models that the cold air is right there but then seems to retreat and the cold air seems to just be transient. It comes, it goes. No real staying power. I quess thats the reality of no NAO blocking.

[DaculaWeather]

This is most likely due to the strat warming breaking apart the polar vortex. This is exactly what we want to happen.

Here's the UKMet at the beginning (06hr) and end (144hr) of its run. You can see how all the cold air is bottled up around the north pole in the first image (dark purple showing low heights). Then at 144hr, the low heights are split up into a few pieces. Also, the ridge is going up through AK, which is better than the 00z GFS op's placement west of AK.

[DaculaWeather]

I'm not so convinced that this might not end up being something for someone, that's a very supressed track for the low, at least compared to what we're been getting.

[msuwx]

Just put up my morning discussion and video. Especially take a look at the video....I spend a lit of time discussing the long-range.

The Alaska block brings the coldest air in the hemisphere to Canada, but what happens with the cold air? That's the big question.

Blog discussion and video

[HKY_WX]

I'm not so convinced that this might not end up being something for someone, that's a very supressed track for the low, at least compared to what we're been getting.

The day 8 area has potential. With that 50/50 low and the incoming stj it looks interesting.

[burgertime]

I'll take the look of the 6z GFS all day. If it can continue that trend we are in business . You have two potentials for something big on there.

[nchighcountrywx]

The pattern change is definitely starting but the models still don't have answers for how far south and entrenched the cold will go. Always keep in mind that after 7 days out, the GFS is nothing more than a roll of the dice. Hopefully things will begin to get clearer as the week progresses.

Have a productive week everyone.