December 2022 Medium-Long Range Disco

[mattie g]

  On 12/8/2022 at 8:12 PM, WEATHER53 said:

Probably should have been in hospital for 5 days, then moderate-serious 5 days, then moderating over next 7 days and on 7th day went out and ate heartily , One week later everything closed. 

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Makes sense

[nj2va]

  On 12/8/2022 at 8:21 PM, WxUSAF said:

I think there’s a long shot chance at something on the front end of that big cutter/cutoff low. Need a piece of energy to run our ahead along the warm front while we have CAD. I think the chance we get anything from a coastal redevelopment is nil.

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Yep, a few OP runs over the last day have shown that scenario too that I posted last night.  While odds are low, interesting things can happen with blocks and 50/50 lows.

[frd]

Hope they are correct this time.  

 

 

 

[WxUSAF]

  On 12/8/2022 at 8:26 PM, nj2va said:

Yep, a few OP runs over the last day have shown that scenario too that I posted last night.  While odds are low, interesting things can happen with blocks and 50/50 lows.

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That low is continuing to trend south and slower as it gets shoved under the block and this weekend’s light NE event turns into a big ocean low and also suppresses the flow. So there’s some room there if we can get some precip to stretch our toward us. I think this weekend and Mon-Thurs of next week could be pretty sneakily cold.

[frd]

  On 12/8/2022 at 8:40 PM, WxUSAF said:

I think this weekend and Mon-Thurs of next week could be pretty sneakily cold.

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Allen mentioned cold air damning through this period.  Looks like low to mid 20's for overnight lows in my area next Tuesday and Wednesday morning. 

 

 

[frd]

 

500mb anomaly clusters from the WPC show very good agreement on the - EPO and West based - NAO regime. 

 

 

 

[Ji]

  On 12/8/2022 at 8:27 PM, frd said:

Hope they are correct this time.  

 

 

 

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i hope those dashes arnt the storm tracks lol

[yoda]

There are a couple loltastic 12z EURO ensemble members for next Friday into Saturday FWIW

[SnowGolfBro]

  On 12/8/2022 at 9:22 PM, yoda said:

There are a couple loltastic 12z EURO ensemble members for next Friday into Saturday FWIW

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Go on………

[yoda]

  On 12/8/2022 at 9:22 PM, SnowGolfBro said:

Go on………

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Through 240, 8 members drop greater then or equal to 2" of snow at DCA.  4 members drop 6"+... while 2 members are full fledged snowstorms (one member for all and one member for N VA/C MD)

[WxUSAF]

@psuhoffman @CAPE @Ian or anyone else with a photographic memory or with a good database: have we ever had a -EPO/-AO/-NAO/-PNA pattern in a La Niña December? Or any La Niña winter month? And if so, what did they produce?

[Maestrobjwa]

  On 12/8/2022 at 9:29 PM, yoda said:

Through 240, 8 members drop greater then or equal to 2" of snow at DCA.  4 members drop 6"+... while 2 members are full fledged snowstorms (one member for all and one member for N VA/C MD)

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Hence my question about just how far south the block could push that low initially...lol Too early to know yet, I'm guessing

[SnowGolfBro]

  On 12/8/2022 at 9:29 PM, yoda said:

Through 240, 8 members drop greater then or equal to 2" of snow at DCA.  4 members drop 6"+... while 2 members are full fledged snowstorms (one member for all and one member for N VA/C MD)

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Thanks @yoda!  Looking forward to @Weather Will posting ensemble snow %. Nice to have a good pattern setting up early in the season. Now we just need some discrete threats and LUCK!

[psuhoffman]

  On 12/8/2022 at 9:30 PM, WxUSAF said:

@psuhoffman @CAPE @Ian or anyone else with a photographic memory or with a good database: have we ever had a -EPO/-AO/-NAO/-PNA pattern in a La Niña December? Or any La Niña winter month? And if so, what did they produce?

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Not really unless you go WAY back…nothing the last 30 years. The closest comp would be March 2018. 

This is a lot more typical of a Nino longwave pattern up top actually, but the central pac makes this a super rare look overall. Not a lot of great comps. Even the top analogs aren’t really all that close for the best analog. But the best matches Imo were periods in Dec 1970, 1978, and 1989. 

[psuhoffman]

@WxUSAF there is actually one fairly recent really good December -epo/AO/NAO/pna pattern match.  Not a Nina though.  

[psuhoffman]

not saying just saying.  Keep in mind there was no snow in the cities during this period. There was a nice event NW and a front end snow to rain again NW during this period but the big snow came after when a pna temporarily popped. 
 

But I think its worth pointing out a couple things that could be pertinent if this in fact is the type of pattern we end up with. While non having a Nino will limit potential due to less STJ the pattern is the pattern.  If a non Nina pattern happens in a Nina the atmosphere isn’t going to be like “no we can’t let it snow cause it’s a Nina”. The challenge is usually getting a non Nina pattern during a Nina!  Second, we don’t need a long lived pna ridge. If we can just get a temporary one for a few days that kind of pattern is loaded.  That’s how 2009 happened.  A pna ridge popped at the right time allowing one of the ejecting waves from the west to dig into the east and not try to cut. And….voila. 

[AtlanticWx]

  On 12/8/2022 at 9:30 PM, WxUSAF said:

@psuhoffman @CAPE @Ian or anyone else with a photographic memory or with a good database: have we ever had a -EPO/-AO/-NAO/-PNA pattern in a La Niña December? Or any La Niña winter month? And if so, what did they produce?

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December-wise, what came up in my program was December 1967 and December 1996. Both of these had a pretty stout -PNA though so not sure if it's the best analog. Snow totals for both months at KIAD were 4.9" and 1.9" respectively.

[CAPE]

If the 18z GFS simulation were to come to fruition, a quick chase up to central PA might be considered for late next week.

[IronTy]

  On 12/8/2022 at 8:26 PM, nj2va said:

Yep, a few OP runs over the last day have shown that scenario too that I posted last night.  While odds are low, interesting things can happen with blocks and 50/50 lows.

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I'm looking at spending christmas weekend camping on meadow mountain, how do we look for snow?

[Ji]

  On 12/8/2022 at 10:33 PM, CAPE said:

If the 18z GFS simulation were to come to fruition, a quick chase up to central PA might be considered for late next week.

That's dc metro loser moves

[WxUSAF]

Thanks @psuhoffman and @AtlanticWx. 1989 makes sense. Those 1967/1996 seem like too much -PNA (we hope).

[Eskimo Joe]

  On 12/8/2022 at 11:25 PM, WxUSAF said:

Thanks @psuhoffman and @AtlanticWx. 1989 makes sense. Those 1967/1996 seem like too much -PNA (we hope).

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My brother was bon in December 1989 in Philly. My parents remark to this day how cold that month was.

[CAPE]

  On 12/8/2022 at 11:27 PM, Eskimo Joe said:

My brother was bon in December 1989 in Philly. My parents remark to this day how cold that month was.

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Wasn't that the year where it snowed for Thanksgiving(more SE of I-95), Dec was super cold, the Bay froze, then by mid Jan winter was over?

[nj2va]

  On 12/8/2022 at 10:48 PM, IronTy said:

I'm looking at spending christmas weekend camping on meadow mountain, how do we look for snow?

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We always spend between Christmas and New Years there - way too far out to talk specifics and chances but pattern leading up to Christmas is looking really nice so far.  

 

[nj2va]

  On 12/8/2022 at 10:33 PM, CAPE said:

If the 18z GFS simulation were to come to fruition, a quick chase up to central PA might be considered for late next week.

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That was a sweet run for them.  I am really starting to like the look of that for the mountains.  Verbatim, 18z is snow to ice to snow (and upslope will crank with that upper level setup).  I’m flying back from a work trip Thursday night but we’re heading straight to Deep Creek from the airport - could be fun times.

[CAPE]

  On 12/8/2022 at 11:40 PM, nj2va said:

We always spend between Christmas and New Years there - way too far out to talk specifics and chances but pattern leading up to Christmas is looking really nice so far.  

 

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Pretty good odds out that way there will be multiple snow chances leading up to and including Xmas, given how the currently depicted pattern looks. Whatever falls should mostly be able to stick around during that period.

[George BM]

  On 12/8/2022 at 11:35 PM, CAPE said:

Wasn't that the year where it snowed for Thanksgiving(more SE of I-95), Dec was super cold, the Bay froze, then by mid Jan winter was over?

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Affirmative.

[nj2va]

Last several runs for next week’s cutter/redeveloper.  This is one of those threats that could trend in our favor in the MR with the block and 50/50 low that @WxUSAF also mentioned.  

[frd]

  On 12/8/2022 at 11:45 PM, CAPE said:

Pretty good odds out that way there will be multiple snow chances leading up to and including Xmas, given how the currently depicted pattern looks. Whatever falls should mostly be able to stick around during that period.

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You're not concerned with the EPS at the end of it's run? It shows - PNA and most significant snowfall would be well to our North and West.  Favors the West and Midwest. Of course it's one run , one model. Total speculation. Granted - EPO on the EPS,  but not sure we benefit snow-wise. 

[snowmagnet]

  On 12/8/2022 at 11:35 PM, CAPE said:

Wasn't that the year where it snowed for Thanksgiving(more SE of I-95), Dec was super cold, the Bay froze, then by mid Jan winter was over?

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I was coming home to southern MD from college for Thanksgiving of '89, so I can assure you we got snow   The rain changed to snow around Lake Anna on my way up I-95.  It was a very long drive home.