December Med/Long Range Discussion

[H2O]

Models finally showing the possibilities once flow buckles. Wouldn't surprise me to see mid week get a little better as well. Slop for next weekend will make thing s interesting for sure

[mitchnick]

23 minutes ago, H2O said:

Models finally showing the possibilities once flow buckles. Wouldn't surprise me to see mid week get a little better as well. Slop for next weekend will make thing s interesting for sure

I'm all for sooner than later because long range stuff rarely works out as modeled 7+ days before. But whatever the mid week system does, it will be setting the stage for next weekend. Only then will we know where the arctic boundary sits.

[Bob Chill]

Euro ens doesn't have much upside for the midweek deal. Not much support for the totals that the op spit out. Consensus is more in the T-1" and not 2"+. 

At shorter leads the ensembles will usually jump towards the op though. Hopefully 12z keeps the party rolling. 

As said earlier, next weekend has a lot of support for a kitchen sink storm. The muddy part is what happens after the switch and not whether we get get frozen or not. For a long lead there is unusually strong support 

[usedtobe]

7 hours ago, stormtracker said:

For some reason, I'm liking this one more than next weekend so far...but waiting on word on that one..

The ggem has no snow for the mid week event but has lots of sleet for the weekend storm.  looks similar to the euro for that storm but pretty much all sleet to freezing rain to rain, a wintery mess but no snow.  My guess is the Euro would yield more sleet and freezing rain than snow despite the 850 temps as warming would come in firsst above 850 mb. 

[WinterWxLuvr]

10 minutes ago, Bob Chill said:

Euro ens doesn't have much upside for the midweek deal. Not much support for the totals that the op spit out. Consensus is more in the T-1" and not 2"+. 

At shorter leads the ensembles will usually jump towards the op though. Hopefully 12z keeps the party rolling. 

As said earlier, next weekend has a lot of support for a kitchen sink storm. The muddy part is what happens after the switch and not whether we get get frozen or not. For a long lead there is unusually strong support 

I'll say.  There is extremely little support for the mid week deal.

Probably means we get hammered.  

[showmethesnow]

9 minutes ago, WinterWxLuvr said:

I'll say.  There is extremely little support for the mid week deal.

Probably means we get hammered.  

Actually I do think we are starting to see support for a midweek storm showing up on the ESP. Not sure if you have weatherbell, but if you do look at the +low locations at hour 126 on the 00Z. Where as previous runs have had lows scattered  all over the place at different times the 00Z run now shows a fairly significant camp of members showing low pressure off the coast in the same time frame. At this point it is showing wide right with little impact for our region but the tendencies I have noticed over the last few runs suggest we may very well see an adjustment closer towards the coast. Guess we will see.

[BristowWx]

5 hours ago, Wonderdog said:

Looks like we have possible frozen events on the GFS on the 15th; 17th; 23rd; and for Bristow a frontal passage for the 25th (which could be a lot more). Once we get by the Monday thing, things get interesting to be sure. But we have to get lucky and get the cold air to get below us.

Thank you.  I was in bad spirits last night and took it out on the 00z GFS.  I like where we are at for sure.

[psuhoffman]

Eps ensembles don't support the torch for next Sunday on the op. Most slide a series of waves along the front to our southeast. The first wave Friday into Saturday is snow on most. The next two waves are a mixed bag leaning towards ice. Some of them imply epic ice totals. I saw quite a cluster that drops well over 1" qpf over several waves with temps below freezing. The consensus is definitely 3-4" snow then a "crap ton" of ice. It's a technical term. The eps is also starting to get interested in the period around the 19-21. Another spike in snowfall totals there. overall the mean jumped around 1.5" and it up to 5.5 in DC and around 8" towards the PA line. That's the trend we should see as we move towards the event if it's a real threat as we should start losing the low outliers. Only a small cluster showing no snow now. Definitely a good run. 

ETA most extreme run might be e44 that drops about 10" from the first two waves then about 1.5 qpf ice over the next 24 hours and temps never get above freezing the whole 3 day storm.  There  are several not much better. Lots of runs with 6" then an inch of ice. 

[mattie g]

1 minute ago, psuhoffman said:

Eps ensembles don't support the torch for next Sunday on the op. Most slide a series of waves along the front to our southeast. The first wave Friday into Saturday is snow on most. The next two waves are a mixed bag leaning towards ice. Some of them imply epic ice totals. I saw quite a cluster that drops well over 1" qpf over several waves with temps below freezing. The consensus is definitely 3-4" snow then a "crap ton" of ice. It's a technical term. The eps is also starting to get interested in the period around the 19-21. Another spike in snowfall totals there. overall the mean jumped around 1.5" and it up to 5.5 in DC and around 8" towards the PA line. That's the trend we should see as we move towards the event if it's a real threat as we should start losing the low outliers. Only a small cluster showing no snow now. Definitely a good run. 

Thanks, psu.

I'm personally not a fan of changeovers *at all* (hated them since I was a kid when I saw far too many of them), but if we get a few chances then I can't see a reason to complain at this time of year.

[WinterWxLuvr]

55 minutes ago, showmethesnow said:

Actually I do think we are starting to see support for a midweek storm showing up on the ESP. Not sure if you have weatherbell, but if you do look at the +low locations at hour 126 on the 00Z. Where as previous runs have had lows scattered  all over the place at different times the 00Z run now shows a fairly significant camp of members showing low pressure off the coast in the same time frame. At this point it is showing wide right with little impact for our region but the tendencies I have noticed over the last few runs suggest we may very well see an adjustment closer towards the coast. Guess we will see.

 

6 minutes ago, psuhoffman said:

Eps ensembles don't support the torch for next Sunday on the op. Most slide a series of waves along the front to our southeast. The first wave Friday into Saturday is snow on most. The next two waves are a mixed bag leaning towards ice. Some of them imply epic ice totals. I saw quite a cluster that drops well over 1" qpf over several waves with temps below freezing. The consensus is definitely 3-4" snow then a "crap ton" of ice. It's a technical term. The eps is also starting to get interested in the period around the 19-21. Another spike in snowfall totals there. overall the mean jumped around 1.5" and it up to 5.5 in DC and around 8" towards the PA line. That's the trend we should see as we move towards the event if it's a real threat as we should start losing the low outliers. Only a small cluster showing no snow now. Definitely a good run. 

Encouraging posts!  Good job guys.

[Deck Pic]

10 minutes ago, mattie g said:

Thanks, psu.

I'm personally not a fan of changeovers *at all* (hated them since I was a kid when I saw far too many of them), but if we get a few chances then I can't see a reason to complain at this time of year.

Probably 50% of our snow events mix or flip. Especially this year with storms tracking to our west. Learn to like them  

[Bob Chill]

5 minutes ago, Deck Pic said:

Probably 50% of our snow events mix or flip. Especially this year with storms tracking to our west. Learn to like them  

They're a lot of fun to track and analyze at short leads. You and I had some good times picking apart some of the events in 13/14 and 14/15. Although one of the events flipped to snow a good but later than we thought. Can't remember which one but I do remember being pissed off with rain at 11pm when it should have been snow at 9. Lol

[Thanatos_I_Am]

For those who do not have wxbell I'll do my best to recap the ensembles. As Bob said, the 0z EPS does not show much support for the midweek system. Although, as mentioned,  a few show a couple of inches. After that wave, the EPS mean in DC is at .5". Where it gets interesting is that potential system next weekend. After that wave rolls through the EPS mean for DC jumps to 4" (3.5" from that wave). Looking at the panels, as with most ensembles, there are a few camps. One being a big fat whiff, of which I counted roughly 11. The second supporting a decent event anywhere up to 6". I counted 20 members of the 51. The third camp I noticed was a bigger thump (over 6"). I counted roughly 15, with few of those 15 showing a 12"+.

When looking at the 06z GEFS, there is again very little support for the midweek system. About .5" on the mean for DC. A couple show a few inches, but they seem to be an out-liar of sorts atm. Much like the 0z EPS, the 06z GEFS jumps after the weekend system. This time from .5" to 6". I know, I know, there is only 20 members so the data is more prone to extremities. Even so, I counted 6 misses for DC, 3 decent hits (up to 6"), and 11 good hits (6"+). 

It seems like there is a disconnect from the OP Euro and the EPS in the end of the weekend event. Many EPS members support a couple inches of back end snow while the Euro shows driving rain the whole rest of the way.

[WinterWxLuvr]

3 minutes ago, Bob Chill said:

They're a lot of fun to track and analyze at short leads. You and I had some good times picking apart some of the events in 13/14 and 14/15. Although one of the events flipped to snow a good but later than we thought. Can't remember which one but I do remember being pissed off with rain at 11pm when it should have been snow at 9. Lol

Don't forget the famous Dec 2012 "Chill" storm that you and I wouldn't let die.  It was a lot better out here but still fun.

[clskinsfan]

A lot will depend just how cold the entrenched air ends up for the Saturday event. We can do well with these front end thumpers. The February 2015 cutter stayed all snow here as we dry slotted before the upper levels warmed. That was true arctic air mass though and yielded over 8 inches.

[Bob Chill]

Thanatos, couple important things to keep in mind with ens snow output and ens in general:

It's pretty common for ensembles to follow the ops once you get to 4-5 day leads. Especially the euro. Don't be surprised with large jumps in ens output if the op jumps run over run. 

Also, snow output with mixed events is usually way too agressive. Between the lower resolution and not so great algorithm, many times what looks like snow on the panels actually shouldn't be. Wes' post earlier is important. The snow algorithm is mostly based on 850hpa and surface temps. A warm nose above 850 turning to sleet will still show as snow on the output. 

[Thanatos_I_Am]

Thanatos, couple important things to keep in mind with ens snow output and ens in general:

It's pretty common for ensembles to follow the ops once you get to 4-5 day leads. Especially the euro. Don't be surprised with large jumps in ens output if the op jumps run over run. 

Also, snow output with mixed events is usually way too agressive. Between the lower resolution and not so great algorithm, many times what looks like snow on the panels actually shouldn't be. Wes' post earlier is important. The snow algorithm is mostly based on 850hpa and surface temps. A warm nose above 850 turning to sleet will still show as snow on the output. 

Thanks for the tips ... still learning.

[Bob Chill]

3 minutes ago, clskinsfan said:

A lot will depend just how cold the entrenched air ends up for the Saturday event. We can do well with these front end thumpers. The February 2015 cutter stayed all snow here as we dry slotted before the upper levels warmed. That was true arctic air mass though and yielded over 8 inches.

Another imortant piece of the puzzle for snow chances is how quick precip gets here. The cold will be retreating. That's almost a given. Ens mean precip panels show potential for a faster onset than the op run. Mean panels actually have almost .1 through most of the region by 0z Saturday and then .15 by 6z. That's fairly significant qpf on the means for the lead time and a good bit faster than the op run. Earlier onset the better in this case 

[mattie g]

27 minutes ago, Deck Pic said:

Probably 50% of our snow events mix or flip. Especially this year with storms tracking to our west. Learn to like them  

Oh...I fully understand that we often change over, and that the farther east you are the faster you flip. I grew up with that happening regularly in South Jersey; I despised it then and haven't been able to shake that hate all these years later.

I can't learn to love changeover, messy events. I'll begrudgingly accept them, but I don't think I'll ever fully embrace them.

[H2O]

22 minutes ago, clskinsfan said:

A lot will depend just how cold the entrenched air ends up for the Saturday event. We can do well with these front end thumpers. The February 2015 cutter stayed all snow here as we dry slotted before the upper levels warmed. That was true arctic air mass though and yielded over 8 inches.

This is when snowpack over the NE can help with that. Keep that area cold and let it funnel down right up to when precip starts

[LP08]

GFS with the dusting idea Wednesday afternoon/evening


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[WinterWxLuvr]

GFS just too fast with the cold push on Wed. Hopefully it's showing it's usual bias and this ends up with more time to develop.

[usedtobe]

Last night's Euro was probably about as good as you could hope for with the Wednesday afternoon/night event.  The big vortex to our north doesn't allow much room for an vort  to deepn enough to really back our flow so I don't see the wave getting any stronger than forecast by the Euro and think the slightly flatter GFS dusting idea could be just as right.  Think the dusting to inch idea is more likely than heavier amounts. 

 

[psuhoffman]

6z gefs now up to 9" mean in DC. They are slightly less bullish then eps on the Friday Saturday period. They do support about 3" then ice, it's a small difference, but a few less big hits there. They are even more bullish on the 19-21 window though with about a 4" mean on that period which is extremely bullish for that range. 

[Bob Chill]

Cold dome backed off on the gfs. Not as deep. Not a good run.

[Yeoman]

Toss

[Ji]

4 minutes ago, Bob Chill said:

Cold dome backed off on the gfs. Not as deep. Not a good run.

GFS is one disaster after another...we almost get dry slotted..and there is no cold

[CAPE]

That 1040 high though..

[psuhoffman]

1 hour ago, Thanatos_I_Am said:

For those who do not have wxbell I'll do my best to recap the ensembles. As Bob said, the 0z EPS does not show much support for the midweek system. Although, as mentioned,  a few show a couple of inches. After that wave, the EPS mean in DC is at .5". Where it gets interesting is that potential system next weekend. After that wave rolls through the EPS mean for DC jumps to 4" (3.5" from that wave). Looking at the panels, as with most ensembles, there are a few camps. One being a big fat whiff, of which I counted roughly 11. The second supporting a decent event anywhere up to 6". I counted 20 members of the 51. The third camp I noticed was a bigger thump (over 6"). I counted roughly 15, with few of those 15 showing a 12"+.

When looking at the 06z GEFS, there is again very little support for the midweek system. About .5" on the mean for DC. A couple show a few inches, but they seem to be an out-liar of sorts atm. Much like the 0z EPS, the 06z GEFS jumps after the weekend system. This time from .5" to 6". I know, I know, there is only 20 members so the data is more prone to extremities. Even so, I counted 6 misses for DC, 3 decent hits (up to 6"), and 11 good hits (6"+). 

It seems like there is a disconnect from the OP Euro and the EPS in the end of the weekend event. Many EPS members support a couple inches of back end snow while the Euro shows driving rain the whole rest of the way.

Be careful not to mix or overlap events. There is a wave Friday/Saturday and then another distinct window in the Sunday night to Tuesday period. Since they are wave lows riding along the boundary there is a lot of spread but just looking at the jump in snow from Friday to Monday cross pollinates the two.  either way the gefs support some snow from both windows and it's the first time the majority indicates two hits. 

[CAPE]

sleet/zr with the trailing low