December 2022 Medium-Long Range Disco

[AtlanticWx]

GEFS 250mb wind plot vs. composite of 250mb winds around or during some of our biggest hits around DC. Can see a few similarities. Exciting pattern coming up, just need to see if anything materializes out of it.

[Cobalt]

On 12/11/2022 at 7:30 PM, psuhoffman said:

That hasn’t been my experience. Just going back over some notably great patterns…

Feb 2021 is one that stands out to me in recent memory. I had to look back at the h500 maps and it looks like we actually had a +PNA during the first half of that blocking period in January. The issue was that there had been a raging +EPO that helped in scouring out any sustained cold in Canada, so storms became shredded messes as they made their way eastwards. It took more than 3 weeks to sustain cold enough airmasses for adequate threats in the East, misses or otherwise. That was when someone (I can't remember who) brought up the data on how DC tends to reliably sustain at least one stretch during each met winter where snow doesn't fall for at least 3-4 weeks (if not more), almost regardless of the underlying patterns. That's been a way for me to mitigate expectations when favorable patterns develop and wane, and as you brought up, it typically takes some time for the stage to get set, even in our most dynamic and favorable setups. 

[WxUSAF]

@AtlanticWx and @DarkSharkWX, appreciate your contributions as new members 

[clskinsfan]

Anyone know where I can find Northern Hemisphere upper air maps for December of 1983? That is the king of December arctic outbreaks for me. We were -7 on Christmas morning here. 

[nj2va]

Regarding Thursday’s storm, one thing to keep an eye on regarding potential for icing are the dews.  18z Euro is showing DPs at 12 out in the mountains and teens/low 20s for the 81 corridor/N MD.  This would lead to evaporational cooling as precip breaks out overnight Wednesday into Thursday.  

[osfan24]

12 minutes ago, Maestrobjwa said:

The Feb system gave central MD almost that much...but not sure about DCA

Oh man, forgot about that one for a second. Oddly, that storm was irritating to me. Got dumped on overnight and then dripped during the day and went from about a foot of snow down to a few inches. Meanwhile, I think PSU stayed colder and it kept snowing there all afternoon and he got like 20+.

[WxUSAF]

1 minute ago, osfan24 said:

Oh man, forgot about that one for a second. Oddly, that storm was irritating to me. Got dumped on overnight and then dripped during the day and went from about a foot of snow down to a few inches. Meanwhile, I think PSU stayed colder and it kept snowing there all afternoon and he got like 20+.

I got 18” out of that split between 14” in the WAA and then 4” with the ULL in the evening 

[Buddy1987]

5 minutes ago, clskinsfan said:

Anyone know where I can find Northern Hemisphere upper air maps for December of 1983? That is the king of December arctic outbreaks for me. We were -7 on Christmas morning here. 

I honestly kinda thought University of Wyoming would have something. Only thing I could really find was a Washington Post article that has a lot of similarities between 1983 and then the 2013 setup. 

https://www.washingtonpost.com/news/capital-weather-gang/wp/2013/12/06/current-pattern-draws-comparisons-to-that-from-historically-cold-December-1983/

[osfan24]

1 minute ago, WxUSAF said:

I got 18” out of that split between 14” in the WAA and then 4” with the ULL in the evening 

That was when I was in Elkridge so I was a bit east of you then. I did get a couple inches tacked on in the evening, but overall, was disappointing for me given all the melting and what surrounding areas received. Guessing I would have fared quite a bit better at my current location.

[nj2va]

2 minutes ago, WxUSAF said:

I got 18” out of that split between 14” in the WAA and then 4” with the ULL in the evening 

I remember doing an epic walk in the middle of the night while snow was puking.  That WAA was fun.

[Buddy1987]

Just now, nj2va said:

I remember doing an epic walk in the middle of the night while snow was puking.  That WAA was fun.

Need Jebman to give his analysis and break down the play by play on his walk for that one 

[Cobalt]

10 minutes ago, clskinsfan said:

Anyone know where I can find Northern Hemisphere upper air maps for December of 1983? That is the king of December arctic outbreaks for me. We were -7 on Christmas morning here. 

https://psl.noaa.gov/data/composites/hour/ This site gives you a lot of parameters to mess around with, so you can change the timeframe and metrics depicted on the map. Definitely a recipe for an icebox as shown in that panel. 

 

[WxUSAF]

5 minutes ago, osfan24 said:

That was when I was in Elkridge so I was a bit east of you then. I did get a couple inches tacked on in the evening, but overall, was disappointing for me given all the melting and what surrounding areas received. Guessing I would have fared quite a bit better at my current location.

 

5 minutes ago, nj2va said:

I remember doing an epic walk in the middle of the night while snow was puking.  That WAA was fun.

Yeah, that WAA ripped. I think the forecast was for like 6-9” or so with it and then a bit more with the ULL? ULL was basically as advertised but the WAA overperformed for sure. Yes the daytime drizzle and 35F melting was annoying but not too bad.

[AtlanticWx]

23 minutes ago, clskinsfan said:

Anyone know where I can find Northern Hemisphere upper air maps for December of 1983? That is the king of December arctic outbreaks for me. We were -7 on Christmas morning here. 

You can create the plot below at https://psl.noaa.gov/cgi-bin/data/composites/printpage.pl btw, but here's a map of Dec 1983 H5 anomalies.

EDIT: Didn't see someone already posted it haha.

[Eskimo Joe]

22 minutes ago, WxUSAF said:

I got 18” out of that split between 14” in the WAA and then 4” with the ULL in the evening 

 

24 minutes ago, osfan24 said:

Oh man, forgot about that one for a second. Oddly, that storm was irritating to me. Got dumped on overnight and then dripped during the day and went from about a foot of snow down to a few inches. Meanwhile, I think PSU stayed colder and it kept snowing there all afternoon and he got like 20+.

 

38 minutes ago, Maestrobjwa said:

The Feb system gave central MD almost that much...but not sure about DCA

That storm featured an intense gradient. Takoma Park got only 5", but Damascus got two reports of over 17" I believe. 

[Paleocene]

2 minutes ago, Eskimo Joe said:

 

 

That storm featured an intense gradient. Takoma Park got only 5", but Damascus got two reports of over 17" I believe. 

Yes. I was in TP at that time and we were quite warm and drippy while folks NW (not even that far NW) partied. As others noted though, that was a great winter so I was able to deal. Especially after the March overperformers that came a few weeks later.

[psuhoffman]

27 minutes ago, osfan24 said:

Oh man, forgot about that one for a second. Oddly, that storm was irritating to me. Got dumped on overnight and then dripped during the day and went from about a foot of snow down to a few inches. Meanwhile, I think PSU stayed colder and it kept snowing there all afternoon and he got like 20+.

I was up in PA that one winter and got 14” but where I am now got 23” according to the coop down the street. 

[TSSN+]

Little icy NW of cities per 18z euro 

[Rhino16]

Hopefully if the pattern arrives, it stays for awhile. Let’s go for 2023 top 10 snowiest year. 

[poolz1]

1 hour ago, psuhoffman said:

I remember all the hits too, unfortunately that’s a much smaller list. 
 

I’m lucky to have a good memory. Secret is I never studied and I’m not that smart…I just remember everything.  I do think there is value in knowing how we’ve failed though.  

Had a roommate at WVU who's memory was very similar.  So frustrating seeing him party while I studied   my butt off and he still scored higher that I did. It is def a gift. 

[nj2va]

8 minutes ago, TSSN+ said:

Little icy NW of cities per 18z euro 

GFS and Euro both creeping up the start times too…now overnight Wednesday into Thursday.  

[Scraff]

9 minutes ago, poolz1 said:

Had a roommate at WVU who's memory was very similar.  So frustrating seeing him party while I studied   my butt off and he still scored higher that I did. It is def a gift. 

Someone say WVU!? 

[poolz1]

1 minute ago, Scraff said:

Someone say WVU!? 

Cheers my friend!   Class of 2000...  Showing my age! lol

[Scraff]

Just now, poolz1 said:

Cheers my friend!   Class of 2000...  Showing my age! lol

Ummmmm. I’d be THRILLED if I was 2000! December 92 for me. Anyway—good to know I’m not the only EER in here.  Now back to tracking our epic pattern…

[mattie g]

1 hour ago, psuhoffman said:

I remember all the hits too, unfortunately that’s a much smaller list. 
 

I’m lucky to have a good memory. Secret is I never studied and I’m not that smart…I just remember everything.  I do think there is value in knowing how we’ve failed though.  

I can’t remember a damn thing, but I’m pretty f’ing smart.

I think.

[mattie g]

1 hour ago, WxUSAF said:

@AtlanticWx and @DarkSharkWX, appreciate your contributions as new members 

I was just thinking exactly the same thing. Excellent new blood!

[AtlanticWx]

This pattern definitely looks favorable, but how does it compare to the biggest Decembers around here?

Below is a plot of the mean snow-to-date climatologically in December from 1980-2021, along with the mean snow-to-date from the top 25% and bottom 25% Decembers snowfall-wise here in DC.

Out of those top 25 Decembers snowfall-wise, here are the H5 anomalies plotted on the Northern Hemisphere for each of them.

The key similarities to our upcoming pattern and the top 25% Decembers' average pattern around here are troughing near Hawaii/the Aleutians, a cutoff ridge north of AK and ridge bridging in the Arctic (-EPO/-AO/-NAO) and the elephant in the room -- lower heights over the EC.

Below is a composite plot of the 250mb plots in these same years (do note that they are smoothed out since they're for the entire month, but you can still make out two key features):

The two key features here are an active STJ and what seems to be a Pacific jet extension, which promotes a +PNA if I remember correctly.

Our upcoming pattern seems to have an active STJ and a jet extension too, which is why we are expected to see a +PNA of some sorts during this pattern.
Overall, our pattern has key similarities to some other patterns of conducive Decembers, snowfall-wise.

[jacindc]

Me, Dec. 1: I'll hit the road to WY as soon as there are three consecutive decent driving days weather-wise, since there's never much snow in the DMV in December.

Me, post-18Z: Or....

(am going to enjoy watching the big blizzard heading to the northern plains tomorrow in the meantime, though!)

[HighStakes]

55 minutes ago, psuhoffman said:

I was up in PA that one winter and got 14” but where I am now got 23” according to the coop down the street. 

That's right! I recorded 24 for the 2 part event. 16 inches with the heavy snow overnight into the morning. Then 1st part ended as some drizzle/ mist. Part 2 was very heavy snow for several hours that evening resulting in 8 more inches. Pretty sure this area bulleyed part 2. If I remember correctly losetoa6 got roughly only 4 inches compared to the 8 here. Sharp cutoff just west of Westminster and just east of the Baltimore/ Carroll county line.

[nj2va]

15 minutes ago, AtlanticWx said:

This pattern definitely looks favorable, but how does it compare to the biggest Decembers around here?

Below is a plot of the mean snow-to-date climatologically in December from 1980-2021, along with the mean snow-to-date from the top 25% and bottom 25% Decembers snowfall-wise here in DC.

Out of those top 25 Decembers snowfall-wise, here are the H5 anomalies plotted on the Northern Hemisphere for each of them.

The key similarities to our upcoming pattern and the top 25% Decembers' average pattern around here are troughing near Hawaii/the Aleutians, a cutoff ridge north of AK and ridge bridging in the Arctic (-EPO/-AO/-NAO) and the elephant in the room -- lower heights over the EC.

Below is a composite plot of the 250mb plots in these same years (do note that they are smoothed out since they're for the entire month, but you can still make out two key features):

The two key features here are an active STJ and what seems to be a Pacific jet extension, which promotes a +PNA if I remember correctly.

Our upcoming pattern seems to have an active STJ and a jet extension too, which is why we are expected to see a +PNA of some sorts during this pattern.
Overall, our pattern has key similarities to some other patterns of conducive Decembers, snowfall-wise.

Fantastic post. Also easy for dummies like me to comprehend.