December Med/Long Range Discussion

[H2O]

front end frozen winter unless we get some Atl help

[BristowWx]

The 6z GFS OP is about the worst run I have seen.  If its close to correct we will be wearing shorts on Xmas.  Even in the shorter term it looks bad for winter precip unless I am totally missing something which is totally possible.    GEFS looks better but these OP runs have to give some pause. 

[H2O]

don't buy what it is trying to sell out that far.  

[psuhoffman]

We pretty much lost the first two threats on all the guidance right now. No idea of that changes but where the gfs goes off on a tangent from its ens and the euro is with the storm the 17th. The one the op euro has a 6-10" across our area.  Gfs barely even has a wave.  Not having that is huge because it's probably our best shot plus it effects everything behind it. Without that storm bombing up to our northeast there is more spacing before the next wave the 19th and do ridging goes nuts up the east coast. No blocking so nothing to stop that from happening. The only thing that keeps us in the game is if we get tight spacing between vorts in this pattern.  That course of events ends all the threats after it as well. The ensembles don't agree (yet) lol. We did lose an inch or so on the mean but that's because we lost the outliers that had snow next week. They are just as bullish if not more so for the 17th and 19th threads. 

[WinterWxLuvr]

GFS and Euro both have similar height patterns across the US at day 10, but the Euro heights are lower for the most part.

Noticeable differences on the day 10 ensemble pattern though. 

[WinterWxLuvr]

Actually after looking at the whole of North America, the ensemble patterns don't look as different.  The GFS has more ridging in the se, but the looks are generally the same.

It looks to me as if the Pacific pattern is pretty good, but there's no sign of blocking in the Atlantic. Maybe somebody else can weigh in on this.

[showmethesnow]

CMC for the win?

First system

After second system.

[CAPE]

27 minutes ago, WinterWxLuvr said:

Actually after looking at the whole of North America, the ensemble patterns don't look as different.  The GFS has more ridging in the se, but the looks are generally the same.

It looks to me as if the Pacific pattern is pretty good, but there's no sign of blocking in the Atlantic. Maybe somebody else can weigh in on this.

Not much in the blocking dept showing up in the means, so maybe we will actually see it. Pacific seems to try to reshuffle in our favor from time to time, but overall the ridging near AK is generally too far west. Whats being advertised on the means is not awful looking , but there are now some hints of SE ridging down the line. As you and many of us have said, the volatility in the pattern precludes giving much credence to any particular look in the guidance beyond about 7 days. I guess going with pattern persistence is as good as anything.

[frd]

14 minutes ago, C.A.P.E. said:

Not much in the blocking dept showing up in the means, so maybe we will actually see it. Pacific seems to try to reshuffle in our favor from time to time, but overall the ridging near AK is generally too far west. Whats being advertised on the means is not awful looking , but there are now some hints of SE ridging down the line. As you and many of us have said, the volatility in the pattern precludes giving much credence to any particular look in the guidance beyond about 7 days. I guess going with pattern persistence is as good as anything.

If anything the trends are for a increasing -EPO . As for the NAO,  it would appear not in the cards any time soon. Really do not need it if we can get enough of a -EPO, and some good luck. 

Of interest is the possibility of a West Pac TC next week,  and whether that comes into play later in December. It would have to gain intensity and recurve favorably though. Also seeing interesting ensemble forecasts for the AO way in the future that look interesting for late month.   

[Bob Chill]

Euro op looked nice of course but we've seen plenty of d8+ stuff on ops so we know the drill. However, digging into the ensembles looks fairly encouraging for late next week. 

A lot of classic signals for low pressure attacking a strong wedge. Many of the eps members have the CAD wedge pushed all the way down in SC right as the storm starts to approach. Tracks are mixed between west/transfer/underneath with those that have a decent event (majority). 

A couple of things that I like seeing on the MSLP/Low Location plots is #1) classic damming signal on the means and #2) no significant cluster of lows near the lakes. This would imply that the wedge won't run like a scared girl because it would be getting scoured by the approaching low from the south and not aided by LP over the lakes which greatly accelerates the process. 

 

Here's the mean 850's for the same panel. A LOT of wiggle room on the means with the 0c line down near NC and again shows the classic CAD signal. 

 

The most common theme on the EPS members is to drive LP into the wedge just west of us in WV and then transfer somewhere along the lines but the transfer won't matter to us. Our show would be over by then. 

 

The bad cluster is a slower progression and everything runs too far west along an approaching front. We're kinda seeing that right now. Too slow on approaching fronts so heights/temps rise and we're fooked. 

There is another cluster with everything squashed far south or a track underneath. However, those members all have ridiculously high HP to the north (like 1040+ kind of stuff). I think this is the least likely scenario. We've seen strong HP's progged at range a few times already but tame down in the med-short range. 

I hope this is a real tracking threat. Prob won't know till Sun unless things start to laser in. IMHO- right now it has the classic look of a strong CAD/TN valley runner. Based on the mean surface temp plots there could potentially be a decent ice event associated with this. All speculation of course and it could just as easily vaporize into nothing but it's something real to discuss for now. 

 

None of this means high probability of anything of course but it's by far the best look we've seen inside of d10 so far. 

[nflwxman]

2 hours ago, psuhoffman said:

We pretty much lost the first two threats on all the guidance right now. No idea of that changes but where the gfs goes off on a tangent from its ens and the euro is with the storm the 17th. The one the op euro has a 6-10" across our area.  Gfs barely even has a wave.  Not having that is huge because it's probably our best shot plus it effects everything behind it. Without that storm bombing up to our northeast there is more spacing before the next wave the 19th and do ridging goes nuts up the east coast. No blocking so nothing to stop that from happening. The only thing that keeps us in the game is if we get tight spacing between vorts in this pattern.  That course of events ends all the threats after it as well. The ensembles don't agree (yet) lol. We did lose an inch or so on the mean but that's because we lost the outliers that had snow next week. They are just as bullish if not more so for the 17th and 19th threads. 

The 17th-18th has been a consensus period for a storm on the ensembles as early as 3 days ago.  Our most frequent winter storms regularly occur as cold air is retreating quickly to the northeast, as it is on almost all the ensembles during that period.  If this arctic air mass is truly the real deal next week, we should hopefully still have a nice wedge in place for a Snow->IP->ZR type scenario as the euro depicts. 

[yoda]

Hmmm.... 06z GFS para looks nice next weekend... two different systems

1st is 198-204... 2nd is 234-240... then it truncates into a rainstorm

[Wonderdog]

11 minutes ago, yoda said:

Hmmm.... 06z GFS para looks nice next weekend... two different systems

1st is 198-204... 2nd is 234-240... then it truncates into a rainstorm

Where do you find that model?

[Bob Chill]

2 minutes ago, Wonderdog said:

Where do you find that model?

 

NCEP has it but Tropical Tidbits has better graphics. It's under the Global tab. 

 

 

[frd]

34 minutes ago, Bob Chill said:

Euro op looked nice of course but we've seen plenty of d8+ stuff on ops so we know the drill. However, digging into the ensembles looks fairly encouraging for late next week. 

A lot of classic signals for low pressure attacking a strong wedge. Many of the eps members have the CAD wedge pushed all the way down in SC right as the storm starts to approach. Tracks are mixed between west/transfer/underneath with those that have a decent event (majority). 

A couple of things that I like seeing on the MSLP/Low Location plots is #1) classic damming signal on the means and #2) no significant cluster of lows near the lakes. This would imply that the wedge won't run like a scared girl because it would be getting scoured by the approaching low from the south and not aided by LP over the lakes which greatly accelerates the process. 

 

Here's the mean 850's for the same panel. A LOT of wiggle room on the means with the 0c line down near NC and again shows the classic CAD signal. 

 

The most common theme on the EPS members is to drive LP into the wedge just west of us in WV and then transfer somewhere along the lines but the transfer won't matter to us. Our show would be over by then. 

 

The bad cluster is a slower progression and everything runs too far west along an approaching front. We're kinda seeing that right now. Too slow on approaching fronts so heights/temps rise and we're fooked. 

There is another cluster with everything squashed far south or a track underneath. However, those members all have ridiculously high HP to the north (like 1040+ kind of stuff). I think this is the least likely scenario. We've seen strong HP's progged at range a few times already but tame down in the med-short range. 

I hope this is a real tracking threat. Prob won't know till Sun unless things start to laser in. IMHO- right now it has the classic look of a strong CAD/TN valley runner. Based on the mean surface temp plots there could potentially be a decent ice event associated with this. All speculation of course and it could just as easily vaporize into nothing but it's something real to discuss for now. 

 

None of this means high probability of anything of course but it's by far the best look we've seen inside of d10 so far. 

 

Nice summary Bob .

 Also helping may well be expansive snow cover to our North and Northwest, and models will tend to underestimate the nature of the air mass , being it will be very cold and dense.  Have seen a fair share of times where the storms have trended colder. Also, low sun angle as well, although that is more non-science I guess.

 

    

 

 

 

[mdsnowlover]

16 minutes ago, yoda said:

Hmmm.... 06z GFS para looks nice next weekend... two different systems

1st is 198-204... 2nd is 234-240... then it truncates into a rainstorm

do you have a link to parallel gfs?? thanks in advance

[yoda]

Just now, mdsnowlover said:

do you have a link to parallel gfs?? thanks in advance

Its on Tropical Tidbits --> Models --> Global --> Para GFS

[yoda]

12z 4km NAM liks some flurries/light snow TV Sun Morn

[psuhoffman]

46 minutes ago, Bob Chill said:

Euro op looked nice of course but we've seen plenty of d8+ stuff on ops so we know the drill. However, digging into the ensembles looks fairly encouraging for late next week. 

A lot of classic signals for low pressure attacking a strong wedge. Many of the eps members have the CAD wedge pushed all the way down in SC right as the storm starts to approach. Tracks are mixed between west/transfer/underneath with those that have a decent event (majority). 

A couple of things that I like seeing on the MSLP/Low Location plots is #1) classic damming signal on the means and #2) no significant cluster of lows near the lakes. This would imply that the wedge won't run like a scared girl because it would be getting scoured by the approaching low from the south and not aided by LP over the lakes which greatly accelerates the process. 

 

Here's the mean 850's for the same panel. A LOT of wiggle room on the means with the 0c line down near NC and again shows the classic CAD signal. 

 

The most common theme on the EPS members is to drive LP into the wedge just west of us in WV and then transfer somewhere along the lines but the transfer won't matter to us. Our show would be over by then. 

 

The bad cluster is a slower progression and everything runs too far west along an approaching front. We're kinda seeing that right now. Too slow on approaching fronts so heights/temps rise and we're fooked. 

There is another cluster with everything squashed far south or a track underneath. However, those members all have ridiculously high HP to the north (like 1040+ kind of stuff). I think this is the least likely scenario. We've seen strong HP's progged at range a few times already but tame down in the med-short range. 

I hope this is a real tracking threat. Prob won't know till Sun unless things start to laser in. IMHO- right now it has the classic look of a strong CAD/TN valley runner. Based on the mean surface temp plots there could potentially be a decent ice event associated with this. All speculation of course and it could just as easily vaporize into nothing but it's something real to discuss for now. 

 

None of this means high probability of anything of course but it's by far the best look we've seen inside of d10 so far. 

Excellent write up as usual.  You are the best read on the forum most days and I am sure that I'm not alone in appreciating your daily contributions. Can't add much that you didn't cover. It's our best threat and it sets up the 19th as well if that storm is still lurking to our northeast. We all know the flaws in the pattern were fighting. As for the para gfs... Great another year with two gfs runs. Lol. As if we didn't already have paralysis by analysis with all the crap out there. Hopefully it proves to be another step in the right direction. The gfs really has improved. We don't see nearly as many crazy unicorn storms at 300 hours on it either. 

[Thanatos_I_Am]

Its on Tropical Tidbits --> Models --> Global --> Para GFS

Wxbell doesn't get all those options I believe... I'd think it would for $25 a month

[WinterWxLuvr]

Placing any sort of trust in operationals right now is risky business.

Posted are the GFS forecasts for Monday morning.  One is its 5 day forecast, the other is its 3 day forecast that just came out.

Seems to me that the push of cold air is constantly being overdone on medium range forecasts.  This isn't the first time.  I think the forecasts of the cold push next week need to be looked at with skepticism. 

[stormtracker]

4 minutes ago, WinterWxLuvr said:

Placing any sort of trust in operationals right now is risky business.

Posted are the GFS forecasts for Monday morning.  One is its 5 day forecast, the other is its 3 day forecast that just came out.

Seems to me that the push of cold air is constantly being overdone on medium range forecasts.  This isn't the first time.  I think the forecasts of the cold push next week need to be looked at with skepticism. 

 

I'm on this train as well.   So far this year, seems like models have been too aggressive with the initial push of cold.

[frd]

21 minutes ago, WinterWxLuvr said:

Placing any sort of trust in operationals right now is risky business.

Posted are the GFS forecasts for Monday morning.  One is its 5 day forecast, the other is its 3 day forecast that just came out.

Seems to me that the push of cold air is constantly being overdone on medium range forecasts.  This isn't the first time.  I think the forecasts of the cold push next week need to be looked at with skepticism. 

I believe the over estimating of cold by the models simply has to with the fact we are still earyl in the transition to the colder pattern. Also, I have seen plenty of times where the cold first invades the West , and then becomes more focused on the Northeast and Mid Atlantic regions.

I bet the repeating snow North and West of here will help the air mass late next week from getting modified on its way Southest.  

[stormtracker]

GFS holds on screwing us midweek.  Can't seem to get the cold air to push south of the M/D line.  

[Interstate]

Just now, stormtracker said:

GFS holds on screwing us midweek.  Can't seem to get the cold air to push south of the M/D line.  

Build a wall???

[WinterWxLuvr]

Just now, stormtracker said:

GFS holds on screwing us midweek.  Can't seem to get the cold air to push south of the M/D line.  

It's an improvement over its prior two runs.  At least there's a small positive.  Lately, every single run that comes out is worse than the prior runs.

Let's start a trend.

[usedtobe]

3 minutes ago, stormtracker said:

GFS holds on screwing us midweek.  Can't seem to get the cold air to push south of the M/D line.  

Gives us a snow showers early Thursday morning behind the front but only enough to say hay, look snow, no accumulation.

 

[yoda]

2 minutes ago, stormtracker said:

GFS holds on screwing us midweek.  Can't seem to get the cold air to push south of the M/D line.  

 

[stormtracker]

Just now, WinterWxLuvr said:

It's an improvement over its prior two runs.  At least there's a small positive.  Lately, every single run that comes out is worse than the prior runs.

Let's start a trend.

Meh, we usually don't win when we're south of the line.  I'll keep watching, but I'm ready to move to the next Lucy.  

[Bob Chill]

19 minutes ago, WinterWxLuvr said:

Placing any sort of trust in operationals right now is risky business.

Posted are the GFS forecasts for Monday morning.  One is its 5 day forecast, the other is its 3 day forecast that just came out.

Seems to me that the push of cold air is constantly being overdone on medium range forecasts.  This isn't the first time.  I think the forecasts of the cold push next week need to be looked at with skepticism. 

 

 

Pretty typical to have cold overestimated in general. Especially out in time. However, the baroclinic zone is carving southward with each successive wave. This is normal early season stuff too but important. Especially with snowcover building southward. If things go in a "typical" progression over time then the amount  that the cold is being over estimated should decrease. Especially in the <D7 range.