Southeast Mid/Long Range Discussion IV

[FoothillsNC]

That time frame is a little closer than what it had been previously showing though right? Before I thought it was showing that ridge often in the 10 day beyond.....now it is around day 8. If it still continues to show it in 48 hours and within the 5-6 day time frame.......than maybe just maybe

yeah the timing is going to be off, but generall right around day 7 is when it shows the building ridge start. The new ensembles agree and it just builds and builds thanks to a strong developing Aluetian Low that pumps up a major ridge, and downstream trough. At 192 to 204 on the ens. I can see a s/w semblence in the southwest, so something is possibly going to dive over the ridge, but who knows if it survives or even comes out from the SW. The ensembles keep the major west ridge/east trough through 312 hours atelast, so thats a pretty long time (for this season) to keep an eastern trough. It doesn't look all that cold though, since the coldest air is well back over Siberia to east Asia, where the other major deep trough is.

[FallsLake]

yeah the timing is going to be off, but generall right around day 7 is when it shows the building ridge start. The new ensembles agree and it just builds and builds thanks to a strong developing Aluetian Low that pumps up a major ridge, and downstream trough. At 192 to 204 on the ens. I can see a s/w semblence in the southwest, so something is possibly going to dive over the ridge, but who knows if it survives or even comes out from the SW. The ensembles keep the major west ridge/east trough through 312 hours atelast, so thats a pretty long time (for this season) to keep an eastern trough. It doesn't look all that cold though, since the coldest air is well back over Siberia to east Asia, where the other major deep trough is.

It seems that when a trough does build in the east it tends to be times when there is not a lot of very cold air in Canada; Just my perspective…. But, I think the million dollar question would be is the air source cold enough in Canada to provide a winter storm in the SE?

[GaWx]

It seems that when a trough does build in the east it tends to be times when there is not a lot of very cold air in Canada; Just my perspective…. But, I think the million dollar question would be is the air source cold enough in Canada to provide a winter storm in the SE?

That makes sense since it means the cold air (wrt to normals) is dumped out of Canada meaning Canada is relatively warm. When there is a lot of very cold air in Canada, it is often because it is stuck there. Canadian air that plunges down here is normally cold enough for mischief regardless.

[tnweathernut]

cold enough to provide a winter storm in the SE?

Even above normal for Canada can make for below to much below average temps here if delivered to us in the proper way.

[packbacker]

yeah the timing is going to be off, but generall right around day 7 is when it shows the building ridge start. The new ensembles agree and it just builds and builds thanks to a strong developing Aluetian Low that pumps up a major ridge, and downstream trough. At 192 to 204 on the ens. I can see a s/w semblence in the southwest, so something is possibly going to dive over the ridge, but who knows if it survives or even comes out from the SW. The ensembles keep the major west ridge/east trough through 312 hours atelast, so thats a pretty long time (for this season) to keep an eastern trough. It doesn't look all that cold though, since the coldest air is well back over Siberia to east Asia, where the other major deep trough is.

This looks cold, it's only there for a couple of days though, and the ensembles don't agree that much....

[GaWx]

Let's say there were a contest to find a week in history that was very cold in the SE US. Let's say I couldn't look at the dates and that I could look at the maps of the Canadian anomalies for the same period and nothing else. I would definitely look for a week with warm Canadian anomalies to have the best shot at a very cold SE US.

[burgertime]

@210 on the Euro there isn't much agreement with the GFS. The Euro is pumping a storm in the GOM but right now it looks like it might push a cold front which course would be after the rain...but we'll see where it goes.

[GaWx]

12Z Doc LR for the SE US: meh.

[burgertime]

12Z Doc LR for the SE US: meh.

Yep looks nothing like the GFS in the 220 time frame.

[Jon]

I have a feeling the ensemble members might pique our interest this afternoon.

I have the same feeling....and off topic but awesome use of pique, most people get the spelling wrong. Bravo.

[Wow]

12Z Doc LR for the SE US: meh.

GOA vortex + positive NAO = more of the same

[packbacker]

I thought the Euro looked OK after day 8....It does have the western ridge at day 8 and just after this a 50/50 low tries to establish, we got a heck of a SE ridge for some reason. You would think with the western ridge and 50/50 low it would squash the SE ridge but it doesn't. With the 50/50 low, western ridge and SE ridge it just squeezes everything up to the lakes.

[burgertime]

I thought the Euro looked OK after day 8....It does have the western ridge at day 8 and just after this a 50/50 low tries to establish, we got a heck of a SE ridge for some reason. You would think with the western ridge and 50/50 low it would squash the SE ridge but it doesn't. With the 50/50 low, western ridge and SE ridge it just squeezes everything up to the lakes.

The Euro ENS might show that.

[Northern Foothills Snowman]

This looks cold, it's only there for a couple of days though, and the ensembles don't agree that much....

From what i've read this has been very common this year .The models seem to be having the hardest time this winter.It feels more like October than January today.Maybe it's a sign of things changing for us.I don't remember seeing another winter like this one and unless it really changes I pray we never have another one like this again.From what i've read it seems a lot like 1960 all over again.

[NTriadwx]

From what i've read this has been very common this year .The models seem to be having the hardest time this winter.It feels more like October than January today.Maybe it's a sign of things changing for us.I don't remember seeing another winter like this one and unless it really changes I pray we never have another one like this again.From what i've read it seems a lot like 1960 all over again.

But, isn't 1960 the year we had snow on four consecutive Wednesdays in March? If it is, I think I'll take please.

[Rankin5150]

Here is the link to the Feb and March of 1960 EXTREME winter weather. That winter started out very weak and "non existent" until mid February. The case study is a very interesting read, becasue it goes into detail about the overall patterns, and what changed in the pattern to provide the phenomenal wintry weather from mid Feb to the THIRD WEEK in March. Amazing...

Here is the link:

http://www.erh.noaa.gov/gsp/localdat/cases/2010/Review_Feb-Mar_1960.pdf

[Stovepipe]

Here is the link to the Feb and March of 1960 EXTREME winter weather. That winter started out very weak and "non existent" until mid February. The case study is a very interesting read, becasue it goes into detail about the overall patterns, and what changed in the pattern to provide the phenomenal wintry weather from mid Feb to the THIRD WEEK in March. Amazing...

Here is the link:

http://www.erh.noaa....eb-Mar_1960.pdf

Wow, 44 inches on the ground! Thanks for posting that, it was a good read.

[Rankin5150]

Here is the link to the Feb and March of 1960 EXTREME winter weather. That winter started out very weak and "non existent" until mid February. The case study is a very interesting read, becasue it goes into detail about the overall patterns, and what changed in the pattern to provide the phenomenal wintry weather from mid Feb to the THIRD WEEK in March. Amazing...

Here is the link:

http://www.erh.noaa....eb-Mar_1960.pdf

Here is an AWESOME writeup from Foothills (Robert):

http://www.easternuswx.com/bb/index.php?/topic/158346-looking-back-at-march-1960/page__fromsearch__1

[Cold Rain]

I think some of the features that are frequently talked about, relating to the 500 mb pattern, and whether or not those features are favorable for Winter wx in the SE, could use a bit of discussion and clarification.

Let's take the Western Ridge/PNA, for example. You can't take one frame of a model and see a western ridge and declare a winter wx potential/cold air outbreak for the SE. Location matters. Height/sharpness matters. Progressiveness matters. A short, progressive ridge is a whole different scenario than a tall, favorably located ridge that has some staying power. Short and progressive usually means a cold frontal passage (cold chasing moisture), followed by cooler weather followed by warmer weather. It doesn't allow SW energy to dig far enough to the south to both spin up a storm and provide a favorable track. A tall ridge that's not as progressive is more likely to provide the opportunity for a significant storm. The location of that ridge helps to determine the storm track. A ridge over or east of the Rockies will usually result in a system tracking too far east for most of us, unless the ridge is really tall and sharp. A ridge a bit west of there is better. All of this though, is usually better than a western trough/-PNA.

Another fun and common feature is the 50/50 low. A weak, quickly moving 50/50 low is going to provide less confluence and suppression than a strong, quasi-stationary one. Again, you should consult more than just, say, the 192 hour panel of the Euro to determine this. To obtain a favorably located, quasi-stationary HP to deliver cold air into the region, a stronger, quasi-stationary 50/50 is better. It will provide the necessary confluence with which to lock in HP. If the 50/50 is weak and zipping along at Warp 6, your timing window for winter wx shortens greatly.

And the last item up for bids is everybody's favorite, the -NAO. For all you newbies out there, this feature is more than just a number put out by the CPC or the CDC or the gfs or the Euro or anything else. Again, you have to look at the height fields at higher latitudes in order to evaluate whether or not you have a -NAO that will help you. Higher heights or a block over iceland or out in the Atlantic is not a preferable configuration if you like winter storms in the SE, all else being equal, even though the index number will be negative. Often, that configuration yields a NW flow, leading to cold and dry, while getting pummeled to death by clipper systems. What you'd want to see are higher heights over Greenland, ridging back into Canada. The Greenland block is a stronger, more stable version of this type of -NAO. These two types of -NAO can help to suppress the storm track and lock in colder air. To evaluate this feature, you should look at the 500 mb pattern over several consecutive time periods in order so see how things are evolving.

None of these things are present to any significant degree on any model output I've seen, going out for the next 10 days to 2 weeks. Until that changes, we're not in a winter wx pattern. In order to get a widespread winter storm, we're going to have to rely heavily on perfect timing with very narrow margins for error. But of course, every now and then, all of the jackpot icons line up on the slot machine.

For non-modeleers, I hope this helps with what to be on the lookout for when model-gazing.

[NTriadwx]

Thanks for the links, very interesting stuff. Always heard my family talking about that winter growing up as a kid. Would have been nice to have seen it.

[LithiaWx]

snip

For non-modeleers, I hope this helps with what to be on the lookout for when model-gazing.

Excellent post, spot on.

[WilkesboroDude]

I think some of the features that are frequently talked about, relating to the 500 mb pattern, and whether or not those features are favorable for Winter wx in the SE, could use a bit of discussion and clarification.

For non-modeleers, I hope this helps with what to be on the lookout for when model-gazing.

Good post.

[RevDodd]

Here is the link to the Feb and March of 1960 EXTREME winter weather. That winter started out very weak and "non existent" until mid February. The case study is a very interesting read, becasue it goes into detail about the overall patterns, and what changed in the pattern to provide the phenomenal wintry weather from mid Feb to the THIRD WEEK in March. Amazing...

Here is the link:

http://www.erh.noaa....eb-Mar_1960.pdf

I was a kid living in Dalton in March of 1960. We have some amzaing ice. My folks have Super 8 movies of the trees for miles around bent over or snapped off.

[burgertime]

For non-modeleers, I hope this helps with what to be on the lookout for when model-gazing.

Great post! Now just put up some pictures lol.

[packbacker]

Great post! Now just put up some pictures lol.

Yes, great post as usual, now enlighten us :-) You didn't like the look of the PNA on the GFS/Euro at day 8? You didn't like the fact a 50/50 low was trying to setup on a day 8 model run to provide some blocking? I thought it looked good, but guess I was wrong....

[Cold Rain]

Thanks guys. On BlackBerry because they locked me out at work, so no pictures! LOL

These things can generate a lot of false excitement if not properly analyzed. On the other hand, false hope might be the only hope this year.

[griteater]

Great post Cold. True, a +PNA takes on many flavors.

[Cold Rain]

Yes, great post as usual, now enlighten us :-) You didn't like the look of the PNA on the GFS/Euro at day 8? You didn't like the fact a 50/50 low was trying to setup on a day 8 model run to provide some blocking? I thought it looked good, but guess I was wrong....

That 50/50 on the euro doesn't close off until day 9 and then opens back up again in the next frame as it's hauling butt out of there. Plus, there's another one of them there splitting troughs out in the west, which is going to yield a frontal passage and a cutoff which will hang around out in the SW until any cold air moves out. Then, as has been the case all season, it'll come out, delivering a nice rain event to the SE. That's what's happening on the Euro.

The GFS never develops any sort of a 50/50 around day 8, but it does have a short, stubby, flat ridge along the west coast, resulting in a broad trough in the east. It provides opportunities for energy to swing over is or to our north....not a favorable orientation or track for a winter storm. It also holds energy back in the SW, which later gets squashed like a bug as it tries to move east.

The good news is, neither of those models will be exactly right. So there's still a chance that things could come together for a minor event somewhere. If I wasn't on BB, I'd throw some maps up. Oh well.

[packbacker]

That 50/50 on the euro doesn't close off until day 9 and then opens back up again in the next frame as it's hauling butt out of there. Plus, there's another one of them there splitting troughs out in the west, which is going to yield a frontal passage and a cutoff which will hang around out in the SW until any cold air moves out. Then, as has been the case all season, it'll come out, delivering a nice rain event to the SE. That's what's happening on the Euro.

The GFS never develops any sort of a 50/50 around day 8, but it does have a short, stubby, flat ridge along the west coast, resulting in a broad trough in the east. It provides opportunities for energy to swing over is or to our north....not a favorable orientation or track for a winter storm. It also holds energy back in the SW, which later gets squashed like a bug as it tries to move east.

The good news is, neither of those models will be exactly right. So there's still a chance that things could come together for a minor event somewhere. If I wasn't on BB, I'd throw some maps up. Oh well.

Agreed, never said it was a great looking 50/50, said it was trying to setup a 50/50. The PNA looked great to me on the GFS OP/ENS and Euro OP but would defer to your call if it doesn't. Also, wasn't looking at any energy coming in on a day 8+ as that seems to change run to run, just looking from a high level if there is a (+PNA/-NAO). But thanks for the feedback, like to learn!

[Cold Rain]

Agreed, never said it was a great looking 50/50, said it was trying to setup a 50/50. The PNA looked great to me on the GFS OP/ENS and Euro OP but would defer to your call if it doesn't. Also, wasn't looking at any energy coming in on a day 8+ as that seems to change run to run, just looking from a high level if there is a (+PNA/-NAO). But thanks for the feedback, like to learn!

Hey, it's all good. And that PNA is better than no PNA, don't get me wrong. But I'm not that crazy about that 50/50 given that it's in and out and given the raging SE ridge. I think all of us have a lot still to learn.