December Medium/Long Range Discussion

[BristowWx]

6 minutes ago, Wentzadelphia said:

I mean let’s be honest. Yoos guys have a similar climate to Georgia. I was trying to be more relatable haha. I don’t think I’ve ever used y’all in real life. Anyone know what time that new 12z jawn runs?

 

 

That would make you update SC.  Funny almost everyone in my neighborhood is from up there somewhere.  Seems you have to go to EZF to find real VA y,all country.   I haven’t seen blocking like what is being modeled since I went on that all cheese diet last year.  Timing and luck combined with pattern hopefully gets it done. 

[SnowDreamer]

Trying to learn to read more than clown maps and skew-t charts here... can someone explain to me why this doesn’t pan out? 00z euro has a big block in the North Atlantic, closed ULL, and surface low tracking to our south. There’s tons of HP around that I feel like should force cold air down into the storm, and something kinda 50/50 ish(maybe a bit too far out to sea)? Looks not bad to me but verbatim we rain/zr. 
 

 

[osfan24]

I'm a relative novice, but to my eyes, it looks like a big trough in the west, so it's flooding the eastern half of the country with pacific air.

[WxUSAF]

@SnowDreamer, look a few panels earlier for where the high pressure to the northeast of us there originates. It’s down along the SE coast! It’s a hot flaming garbage airmass, that’s why it’s rain for everyone. That high to the northwest is legit, but it hasn’t arrived in time. It’s a weird and very unusual evolution. And nine days out so I wouldn’t hold your breath on it.

[Ralph Wiggum]

17 minutes ago, SnowDreamer said:

Trying to learn to read more than clown maps and skew-t charts here... can someone explain to me why this doesn’t pan out? 00z euro has a big block in the North Atlantic, closed ULL, and surface low tracking to our south. There’s tons of HP around that I feel like should force cold air down into the storm, and something kinda 50/50 ish(maybe a bit too far out to sea)? Looks not bad to me but verbatim we rain/zr. 
 

 

Because it is a model guidance at range and not going to nail the surface every time even with a good ul look. Guidance says this period has potential.

[psuhoffman]

3 minutes ago, WxUSAF said:

@SnowDreamer, look a few panels earlier for where the high pressure to the northeast of us there originates. It’s down along the SE coast! It’s a hot flaming garbage airmass, that’s why it’s rain for everyone. That high to the northwest is legit, but it hasn’t arrived in time. It’s a weird and very unusual evolution. And nine days out so I wouldn’t hold your breath on it.

When 2016 showed up at day 10 it was rain on the euro also.  Same reason...marginal airmass. We are getting closer to the part of climo where marginal air masses should work with a good track. 

[SnowGoose69]

24 minutes ago, SnowDreamer said:

Trying to learn to read more than clown maps and skew-t charts here... can someone explain to me why this doesn’t pan out? 00z euro has a big block in the North Atlantic, closed ULL, and surface low tracking to our south. There’s tons of HP around that I feel like should force cold air down into the storm, and something kinda 50/50 ish(maybe a bit too far out to sea)? Looks not bad to me but verbatim we rain/zr. 
 

 

Ridge out west too displaced to the east and not tall enough.  The only case I know of recently where that pattern produced was 12/25/10.  You need a nasty nasty west based block probably to get a DC to Boston snow event with that ridge that displaced east.  2/23/89 was somewhat close as well and we saw that largely failed for most areas other than the immediate coast 

[howrdcounty snow]

doesn't the GFS have this but only a short window of snow?? seems my observations are incorrect. My apologies

[North Balti Zen]

Snowgoose invoking the “storm”-of-infinite-sadness down this way - bad juju friend.

[poolz1]

@nj2va  Sounds like Deep Creek will be the place to be for Christmas.... Hopefully a few of those squalls will make their way over the mountains.  Would be sweet to see snow squall warnings popping up x-mas day. 

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Strong low pressure center and accompanying sfc cold front will
cross the area on Christmas Eve and will be accompanied by
heavy showers, potentially damaging winds, and as much as 2
inches of rain that could lead to flash flooding given saturated
soils from melting snow and very wet second half of the year
over central and southern MD. The showers could end as a very
brief period of snow showers before ending with minimal
accumulation outside of the Appalachians. However, strong CAA
late Thu night will result in rapidly falling temperatures with
a flash freeze possible. Very cold air aloft pouring in late Thu
night and Fri will result in steepening lapse rates and
potential squally weather over the mtns with intense snow
showers possible. Wind chills will also be a concern for the
mtns where sub-zero wind chills are possible and a very cold day
and night Fri-Fri night elsewhere.

[BristowWx]

Not just brief but very brief.  This is trending quite well. 

[George BM]

8 minutes ago, poolz1 said:

@nj2va  Sounds like Deep Creek will be the place to be for Christmas.... Hopefully a few of those squalls will make their way over the mountains.  Would be sweet to see snow squall warnings popping up x-mas day. 

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Strong low pressure center and accompanying sfc cold front will
cross the area on Christmas Eve and will be accompanied by
heavy showers, potentially damaging winds, and as much as 2
inches of rain that could lead to flash flooding given saturated
soils from melting snow and very wet second half of the year
over central and southern MD. The showers could end as a very
brief period of snow showers before ending with minimal
accumulation outside of the Appalachians. However, strong CAA
late Thu night will result in rapidly falling temperatures with
a flash freeze possible. Very cold air aloft pouring in late Thu
night and Fri will result in steepening lapse rates and
potential squally weather over the mtns with intense snow
showers possible. Wind chills will also be a concern for the
mtns where sub-zero wind chills are possible and a very cold day
and night Fri-Fri night elsewhere.

Some runs of the gfs yesterday, particularly the 12z and 18z runs, were aggressive with getting convective snow showers east of the mountains on Christmas morning. We'll see if it becomes more aggressive again and eventually if CAMs pick up on this closer in time.

[aldie 22]

I actually think if you saw accumulating snow last week you will see a bit on Christmas as well. I know that would be a kick in the pills for those that didn't but since most of them have decided to poo poo every model run and potential then the pills it is. Sorry guys

[nj2va]

10 minutes ago, poolz1 said:

@nj2va  Sounds like Deep Creek will be the place to be for Christmas.... Hopefully a few of those squalls will make their way over the mountains.  Would be sweet to see snow squall warnings popping up x-mas day. 

Yeah, upslope will be cranking (and likely will linger past Christmas depending on the setup).....it certainly bears watching the next few days but recent guidance has been hinting at snow showers across the area on Christmas Day which would certainly make for a festive mood.  I’ll be in NJ for Christmas (back in Deep Creek the day after) but I’m hoping this area sees some snow squalls.  

[mattie g]

2 hours ago, Wentzadelphia said:

Y’all are setting yourselves up for failure comparing everything to 96. That was a great 6z run on the gfs. Probably the best look yet for dc/philly. Kind of want the first post Christmas storm to blow up now. Even if it’s rain could serve as 50/50. The storminess is relentless it seems and we have blocking. There’s just no way we don’t cash eventually (we’ll I guess there is lol), but it could be 10000x worst. 

Who's comparing everything to 1996?

Edit: Sorry...I see now that I'm beating a dead horse. My bad.

[anotherman]

1 minute ago, mattie g said:

Who's comparing everything to 1996?

DT posted about the pattern reminding him of '96.

[Dabuckeyes]

GFS is a little sharper with the trough and slightly slower with the advancement of the cold air.  Not what you want to see if you are rooting for some snowflakes on Christmas Eve night

[WinterWxLuvr]

1 minute ago, losetoa6 said:

Gfs further south with the post Xmas energy . Actually a west ridge this run as well forming at 168

And a low moving from Dubuque to Cincinnati and then reforming off Va Beach. Never seen that before lol

[psuhoffman]

3 minutes ago, losetoa6 said:

Gfs further south with the post Xmas energy . Actually a west ridge this run as well forming at 168

The primary comes across too far north. It’s that way across all guidance. Unless that changes (it could) it’s inevitably a miller b screw job. We could eeek out some snow but it’s the setup where we watch north of us cash in. However, a bombing system the 28 helps the setup after. 

[psuhoffman]

1 minute ago, WinterWxLuvr said:

And a low moving from Dubuque to Cincinnati and then reforming off Va Beach. Never seen that before lol

It happens in extreme blocking. I’ve seen analogs like that. But it’s usually a fail for our area. Can’t say 100% sometimes crazy stuff happens but we want a the primary to be bottoming out at our latitude or lower to have a better chance. 

[WxUSAF]

Remember last weeks storm looked like a Miller B at range. Was taking the primary through the Midwest with a transfer to Norfolk area. 

[SnowDreamer]

Is this where someone says "Right where we want it for right now"...? Is that on the weenie bingo sheet?

[psuhoffman]

7 minutes ago, losetoa6 said:

Improved over the last 2 runs . Primary further south . West ridging is new . Curious to see the 50/50 local as we near . Still oodles of time 

 

7 minutes ago, WxUSAF said:

Remember last weeks storm looked like a Miller B at range. Was taking the primary through the Midwest with a transfer to Norfolk area. 

Yes that could change but I think we need to see it move that way in the next 24 hours. We’re getting to that range where the globals have been picking up on the general synoptic setups. We’re right at the lead time where the primary shifted south on guidance opening up the opportunity last week.   I’m not sold on any solution yet. But it looks like there are possibly 4 waves between Dec 28-Jan 5 with blocking setup. They will all affect one another. Spacing and if they amplify into the 50/50 space.  I don’t have a strong feel for how the specifics play out but I do think we would be incredibly unlucky to come out of that period without one decent snowfall. We can pick on the minor imperfections but fact is the look is plenty good enough to snow. Excellent AO/NAO. Strong STJ. Mediocre PAC. That should be good enough to get some snow imo. 

[DownpourDave]

Day 10 gfs is actually a pretty good setup. It holding is another matter though.

[DownpourDave]

3 minutes ago, SnowLover22 said:

Day 10 gfs is actually a pretty good setup. It holding is another matter though.

That arrow should be more ENE but you get the idea. 

[Scarlet Pimpernel]

2 minutes ago, psuhoffman said:

 

Yes that could change but I think we need to see it move that way in the next 24 hours. We’re getting to that range where the globals have been picking up on the general synoptic setups. We’re right at the lead time where the primary shifted south on guidance opening up the opportunity last week.   I’m not sold on any solution yet. But it looks like there are possibly 4 waves between Dec 28-Jan 5 with blocking setup. They will all affect one another. Spacing and if they amplify into the 50/50 space.  I don’t have a strong feel for how the specifics play out but I do think we would be incredibly unlucky to come out of that period without one decent snowfall. We can pick on the minor imperfections but fact is the look is plenty good enough to snow. Excellent AO/NAO. Strong STJ. Mediocre PAC. That should be good enough to get some snow imo. 

Very true, and thanks for pointing this out.  It's definitely one of the better setups we've had in some time it seems (though I won't say "since '96" or any other particular year, hahaha!).   It will be complicated, the interaction of the various waves during that period, and not necessarily "ideal" (whatever that might be).  So yeah, hopefully we'll come out of that time frame with at least one decent snow and avoid the incredible bad luck of getting shut out!

[WxUSAF]

17 minutes ago, losetoa6 said:

Improved over the last 2 runs . Primary further south . West ridging is new . Curious to see the 50/50 local as we near . Still oodles of time 

SO. MANY. SHORTWAVES.

Going to be a volatile forecast post-Xmas I expect.

[DownpourDave]

3 minutes ago, SnowLover22 said:

That arrow should be more ENE but you get the idea. 

System stays weaker this run because the jet-streak upstream is weaker and there is not as much curvature. 

6z

 

12z

 

[WinterWxLuvr]

Look at the one behind it

Never mind lol

[poolz1]

CMC with a good look at the end of the run...