February Pattern and Storm Discussion

[beanskip]

Upper features are pretty close, but there will be giant BL issues to overcome for Mid-South folks given the lack of a cold air source. 5h low pops up, then disappears, then pops up and starts strengthening as it gets near the coast. Need those features to be strong much farther west or it will be a cold rain. Truthfully, I'm not sure even if this thing tracks farther south that it's going to matter.

Robert just tweeted that mid south snow chances are increasing for next week.

[Cold Rain]

I see what you are talking about. I seem to be having trouble getting my posts to post. I wrote out a long one that never went thru. Anyways yes, not a classic nao look with a 50/50. Not sure how Allan gets his values.

I'm not sure of the algorithm, but it's got to be looking at heights relative to normal across the NAO region, which unfortunately takes into account east-based areas. Honestly, I never look at those charts anymore, other than to he'll identify trends. Looking at H5 is of much, much greater value in helping to identify a favorable pattern, IMO.

[WilkesboroDude]

Robert just tweeted that mid south snow chances are increasing for next week.

 

I could have told you that a few days ago. Looks like an Arkansas special...with parts of TN being in there too. Still a few days to chew on this but looks like it is for the regions who have been getting winter weather this winter already...JMO.

[griteater]

I'm not sure of the algorithm, but it's got to be looking at heights relative to normal across the NAO region, which unfortunately takes into account east-based areas. Honestly, I never look at those charts anymore, other than to he'll identify trends. Looking at H5 is of much, much greater value in helping to identify a favorable pattern, IMO.

 

I'm pretty sure he has it based on this map, or similar....difference between the 500mb height anomalies between the 2 regions....and he has 3 measurements - basin-wide NAO, eastern half, and western half (source - http://www.cep.rutgers.edu/~oman/NAO.htm)

 

 

http://imageshack.us/photo/my-images/853/naoreg.jpg/'>

[franklin NCwx]

I'm not sure of the algorithm, but it's got to be looking at heights relative to normal across the NAO region, which unfortunately takes into account east-based areas. Honestly, I never look at those charts anymore, other than to he'll identify trends. Looking at H5 is of much, much greater value in helping to identify a favorable pattern, IMO.

It does bend the height lines thru Greenland and into the Davis Strait area. I guess this is what it's picking up on. That is the best spot for us to get a -nao IMO, In the Davis Strait region.

[burgertime]

GFS has a moderate snow storm as that arctic air passes even down to ATL at 204...of course it's just after truncation so take it for what you will. 

[griteater]

Upper features are pretty close, but there will be giant BL issues to overcome for Mid-South folks given the lack of a cold air source. 5h low pops up, then disappears, then pops up and starts strengthening as it gets near the coast. Need those features to be strong much farther west or it will be a cold rain. Truthfully, I'm not sure even if this thing tracks farther south that it's going to matter.

 

There's more stream separation with the southern wave separating more from the northern piece, and that creates more confluence and sfc high pressure to the north...but I agree, I don't see this southern piece digging far enough south....you'd want to see it dig farther south, and stronger.

[Cold Rain]

I'm pretty sure he has it based on this map, or similar....difference between the 500mb height anomalies between the 2 regions....and he has 3 measurements - basin-wide NAO, eastern half, and western half (source - http://www.cep.rutgers.edu/~oman/NAO.htm)

Awesome! That makes sense.

[nrgjeff]

Lots of bullish data, if you like winter, the last 24 hours for the Mid South and Carolinas. Where do I start, GFS or the European weeklies?

 

The European weekly charts turned sharply colder the next 3 weeks, as mentioned over the last couple pages. GFS and op Euro in good agreement from late next week into the following week for the Southeast. The snow question will depend on individual systems. I still have doubts about V-Day but President’s Day might work out. The issue next week is that buffet line into the West Coast. 12Z GFS just in; continues to insist on Tennessee snow, but probably missing the next Rockies wave upstream. Euro has stronger Rockies wave and shears out Southeast V-Day system. Even if the GFS storm track is correct, I figure it’ll be too warm Southeast. Hope I'm wrong about that. However often when the epicenter of the cold is in the Plains, cold can’t get into the Southeast if WAA ahead of a low. But in the wake…

 

By President’s Day models indicate repeated shortwaves digging into the CONUS trough, which could finally get the Southeast involved. It’s the same buffet line above, so slight risks are to the milder side. However by then we’re getting a little more love from a –NAO. BTW I’d say neither the Atlantic or Pacific have been particularly hostile overall this winter. Smaller scale features have been the issue. December featured a subtle but significant weak ridge over the Deep South that affected all the Southeast. Buffet line into California/West is also a mild signal in the Southeast. If California can quit for a week, Southeast gets something the week of President’s Day.

 

Weeks 3-4 are shown colder than normal in the Southeast on the Euro weeklies. CFS is actually milder, a reversal compared to most of this winter relative to the Euro weeklies. MJO is robust now, and getting ready to enter colder 8,1,2 which helps the week 2 forecast. However what giveth can taketh away if it stays strong into 3-5. MJO forecast to weaken as it stumbles into warmer 3-5 stages in March. As mentioned earlier in the thread, MJO has over-achieved this winter so mild risks are very real weeks 3-4. If the MJO totally dies like two years ago, then the Alaska situation becomes less important relative to the North Atlantic. Greenland blocking shown through week 4 on both weekly products. If the MJO stays robust, Alaska ridge retrogrades and the Southeast warms up weeks 3-4. I lean toward the warmer solution, but hope for the colder.

 

OK, time to go live vicariously through the NYC and Boston Forums. Hammer time!

[griteater]

Awesome! That makes sense.

 

And in the really good blocks, the high anomalies extend well west of Region 1, into Hudson Bay and merge with a +PNA ridge in SW Canada

[valkhorn]

GFS does look really good for central TN and parts of eastern TN. 

 

Esp. for the potential Miller A the week after V Day.

[valkhorn]

GFS has a moderate snow storm as that arctic air passes even down to ATL at 204...of course it's just after truncation so take it for what you will. 

 

It's a good possibility, the pattern favors it towards that time frame. We'll have to see how it pans out.

[franklin NCwx]

Models are moving towards the gfs with a more amped solution today. Congrats west Tenn.

 

 

 

 

 

 

 

 

[Shack]

The fact that the GFS has shown the H5 closed off again at 114-117hrs,having lost it for a couple of runs, should give the Tennessee folks something to ponder.  As Burger noted, a new feature at 189hrs gives Atlanta (as well as, don't laugh, Panama City, (where is PCBjr?), snow. (no soundings to support this, just the 850 line.)

[franklin NCwx]

GEFS are very differnet than the op. I bet there are a few apps runners in the mean.

 

 

 

 

[POWERSTROKE]

I could have told you that a few days ago. Looks like an Arkansas special...with parts of TN being in there too. Still a few days to chew on this but looks like it is for the regions who have been getting winter weather this winter already...JMO.

Robert mentioned this last weekend but said just have to wait and see

[SnowNiner]

Lots of bullish data, if you like winter, the last 24 hours for the Mid South and Carolinas. Where do I start, GFS or the European weeklies?

 

The European weekly charts turned sharply colder the next 3 weeks, as mentioned over the last couple pages. GFS and op Euro in good agreement from late next week into the following week for the Southeast. The snow question will depend on individual systems. I still have doubts about V-Day but President’s Day might work out. The issue next week is that buffet line into the West Coast. 12Z GFS just in; continues to insist on Tennessee snow, but probably missing the next Rockies wave upstream. Euro has stronger Rockies wave and shears out Southeast V-Day system. Even if the GFS storm track is correct, I figure it’ll be too warm Southeast. Hope I'm wrong about that. However often when the epicenter of the cold is in the Plains, cold can’t get into the Southeast if WAA ahead of a low. But in the wake…

 

By President’s Day models indicate repeated shortwaves digging into the CONUS trough, which could finally get the Southeast involved. It’s the same buffet line above, so slight risks are to the milder side. However by then we’re getting a little more love from a –NAO. BTW I’d say neither the Atlantic or Pacific have been particularly hostile overall this winter. Smaller scale features have been the issue. December featured a subtle but significant weak ridge over the Deep South that affected all the Southeast. Buffet line into California/West is also a mild signal in the Southeast. If California can quit for a week, Southeast gets something the week of President’s Day.

 

Weeks 3-4 are shown colder than normal in the Southeast on the Euro weeklies. CFS is actually milder, a reversal compared to most of this winter relative to the Euro weeklies. MJO is robust now, and getting ready to enter colder 8,1,2 which helps the week 2 forecast. However what giveth can taketh away if it stays strong into 3-5. MJO forecast to weaken as it stumbles into warmer 3-5 stages in March. As mentioned earlier in the thread, MJO has over-achieved this winter so mild risks are very real weeks 3-4. If the MJO totally dies like two years ago, then the Alaska situation becomes less important relative to the North Atlantic. Greenland blocking shown through week 4 on both weekly products. If the MJO stays robust, Alaska ridge retrogrades and the Southeast warms up weeks 3-4. I lean toward the warmer solution, but hope for the colder.

 

OK, time to go live vicariously through the NYC and Boston Forums. Hammer time!

 

thanks Jeff, great summary there. 

 

Interested in the bolded.   Is that the "shortwave" verus "longwave" issue?  What part of the models do you look at to identify this buffet line?  Trying to learn about these smaller details and their effect on the SE.  What does it mean if "California can quit"?  Sorry for all the questions, just trying to follow.  Thanks.

[griteater]

The Canadian gets bashed a lot, but it has led the way with the 2/12-2/13 storm, and the 12z looks good for light-moderate snow for Little Rock, Memphis, Nashville corridor.

[jburns]

Well said Don. This is a weather forum. It is just possibilities out there showing on the models. Not like a thread has been started yet.

True enough.  However, when you discuss the possibility of winter weather in the long range and someone says they see nothing but warm and no snow, that is a possibility as well.  Lets go to the verification scores for this year.

[franklin NCwx]

Euro is ots. No apps runner, It also came in much colder at 850.

 

 

[burgertime]

Euro looked like it might turn good but it kind of fizzles out and with no good source of cold air the V-Day storm goes POOF. I'm waiting to see what shows up later in the run that has always looked to hold more potential to me. 

[burgertime]

Just as an FYI the Euro does show some really light snow around I-40 north for V-Day...but it's very light. 

[burgertime]

Well based on hour 198 of the Euro it appears that it is falling to the GFS when it comes to cold making it's way east. Also could be setting up something nice later on though it might get suppressed to Cuba. 

[Poimen]

as has been mentioned before, a lack of a real cold air source is going to dampen any V-Day threat for most of us (if not all), unless the more amplified GFS occurs and some get lucky on the backside. But I would not hold my breath for that (as I'm sure many of you know). Which leaves most of us only a two-week window (at best 4 but I stop looking after March 1) for something to pop.

 

I'm not terribly optimistic, truthfully.

[burgertime]

@210 the Euro is telling ATL to prepare for glory! 

[burgertime]

@216 Euro has a big dog...WOOF....hehe probably not gonna happen but people are gonna love what it shows. 

[packbacker]

I thought the Euro looked better but than kind of fizzled out after day 4.

[burgertime]

On this run just looking at it ATL looks to get 4 - 8 Upstate probably 8 - 10 and most of NC 4-8. Very hard to tell but that would be my guess...can we make this one happen please?  . 

[burgertime]

I thought the Euro looked better but than kind of fizzled out after day 4.

 

This is out past 200. 

[packbacker]

This is out past 200. 

.

Yep, your looking at the day 9 potential, I am talking about the day 5 potential.