January 24-26: Miracle or Mirage Thread 2

[jaydreb]

12 minutes ago, SBYWeather said:

Does anyone happen to have individual 12z EPS members?

 

[Ji]

11 minutes ago, psuhoffman said:

we really should use the median more than we do, I find it more indicative than the mean.  

its not as fun though

[EstorilM]

8 minutes ago, weathercoins said:

Pretty strong language by LWX:

 

568
FXUS61 KLWX 211943
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
243 PM EST Wed Jan 21 2026

.WHAT HAS CHANGED...
A Winter Weather Advisory was issued for western Garrett County for
tonight due to accumulating snow of 2 to 4 inches and ice
accumulation of up to a glaze. The threat for a Major winter storm
continues for this weekend with very cold temperatures expected.


&&

.KEY MESSAGES...
- 1) Major winter storm will impact the region Saturday  afternoon
through Sunday night bringing widespread snow and  mixed
precipitation to southern areas. Arctic high pressure  will build
into the area Friday afternoon into Saturday  morning providing the
source for very cold temperatures this  weekend through early next
week.

- 2) Wintry precipitation over portions of the Alleghenies late
  this afternoon through Thursday morning.

&&

.DISCUSSION...

KEY MESSAGE 1...Major winter storm will impact the region Saturday
afternoon through Sunday night bringing widespread snow and mixed
precipitation to southern areas. Arctic high pressure will build
into the area Friday afternoon into Saturday morning providing the
source for very cold temperatures this weekend through early next
week.

Arctic high pressure will build north of the local area Friday night
into Saturday and settle over southern Quebec providing a classic
cold air damming event. Meanwhile, Gulf moisture will start
overrunning the sfc bdry across the south Fri and expand northward
into our area Saturday afternoon. After review of all available 12Z
deterministic, ensemble guidance including AIFS shows the 12Z
Canadian and EC models remained consistent to their previous runs,
while the 12Z GFS trended more northwestward compared to prior runs
from 24 hrs ago. The 12Z EC also trended colder aloft in the 850-700
mb layer lessening the threat of mixed precip especially over the
northern half of the fcst area, but still with a significant fzra
threat for St. Mary`s County. Probability of a foot of snow or more
is now roughly 50% areawide, except south of the Capital Beltway
where mixed precip is becoming increasingly likely, particularly
across St. Mary`s County. The heavy snow combined with very cold
temperatures in the teens will result in a high impact winter storm
areawide with potentially life-threatening conditions. After the
storm departs late Sunday night, frigid temperatures may pose a risk
of hypothermia, power, phone and shortage of supplies across the
region.

 

Nice - I was waiting for the update, they seemed all-in on the previous AFD as well (unusual for them.) 

[SBYWeather]

3 minutes ago, jaydreb said:

Thank you very much!

[TSSN+]

I feel bad whoever is in the freezing rain bullseye. Going to get over .75 zr, tons of downed trees and power lines and then it won’t melt and will be stuck in the cold for a long time. Will be a nightmare for that zone. 

[MN Transplant]

This is what the Euro looks like above ground over DC.  1000mb at the bottom, going up by 50mb to 800mb and then by 100mb.

So, there isn’t necessarily any sneaky layer, it is just the 850-700mb level we lose later on in the storm.

 

Via Windy

[Ephesians2]

2 minutes ago, TSSN+ said:

I feel bad whoever is in the freezing rain bullseye. Going to get over .75 zr, tons of downed trees and power lines and then it won’t melt and will be stuck in the cold for a long time. Will be a nightmare for that zone. 

Probably going to be me tbh. Will be getting an indoor-safe propane emergency heater and some extra wool blankets tomorrow after seeing those Euro runs. 

[Nomz]

Is there anything concrete I can pick out from raw recon data that would be good/bad or am I just playing the waiting game 

[psuhoffman]

5 minutes ago, MN Transplant said:

This is what the Euro looks like above ground over DC.  1000mb at the bottom, going up by 50mb to 800mb and then by 100mb.

So, there isn’t necessarily any sneaky layer, it is just the 850-700mb level we lose later on in the storm.

 

Via Windy

Thanks... heavy precip holds off the warming...which is normal in these type setups...so we don't actually lose that much qpf to the mix...the thump is mostly snow even in DC according to that 

[WxUSAF]

Just now, psuhoffman said:

Thanks... heavy precip holds off the warming...which is normal in these type setups...so we don't actually lose that much qpf to the mix...the thump is mostly snow even in DC according to that 

A foot before mixing!

I will caveat that with the farther NW track, we don’t get those absurdly deep DGZs like we were looking at a day or two ago. I’d expect more like 10-12:1 in the WAA thump in total.

[SnowenOutThere]

18z NAM near hour 50 showing more separation of the NS and SW hypothetically it should be useful during that time frame 

[Terpeast]

My mom just asked me how much I think we're getting. I gave her a conservative estimate, 6-12" with some sleet. She lives closer to dc proper than I do, so for my own backyard I'd bump that up a couple inches.

[JenkinsJinkies]

1 minute ago, WxUSAF said:

3 minutes ago, psuhoffman said:

 

A foot before mixing!

 

If it even mixes.

[Stormchaserchuck1]

18z NAM at 51hrs has the northern stream further SW than the 12z GFS at 57 by a pretty good amount actually. And the sw near Baja is ejecting more quickly

[mitchnick]

2 minutes ago, Stormchaserchuck1 said:

18z NAM at 51hrs has the northern stream further SW than the 12z GFS at 57 by a pretty good amount actually. And the sw near Baja is ejecting more quickly

Heights are lower a bit on the east coast.

[TSSN+]

DC right at the end of the storm. Talk about riding the line.

 

[clskinsfan]

NAM also has more confluence in the NE than 12Z

[Stormchaserchuck1]

SW energy getting caught up by the northern stream way early on 18z NAM fwiw

[TSSN+]

1 minute ago, Stormchaserchuck1 said:

SW energy getting caught up by the northern stream way early on 18z NAM fwiw

Your analysis is way different than others saying it’s not as phased lol 

[psuhoffman]

5 minutes ago, WxUSAF said:

A foot before mixing!

I will caveat that with the farther NW track, we don’t get those absurdly deep DGZs like we were looking at a day or two ago. I’d expect more like 10-12:1 in the WAA thump in total.

Yea we won't see those 18-1 crazy ratios...BUT...QPF tends to overperform in those crazy WAA driven thumps so it actually tends to be a wash (in terms of snowfall performance compared to modeled QPF.  In one case we overperform due to rations in the other because of QPF.  

[Stormchaserchuck1]

Just now, TSSN+ said:

Your analysis is way different than others saying it’s not as phased lol 

I'm comparing to the 12z GFS. SW piece isn't cutoff on the NAM at hr57

[TSSN+]

Just now, Stormchaserchuck1 said:

I'm comparing to the 12z GFS. SW piece isn't cutoff on the NAM at hr57

It’s looking less than 12z Nam so far so we will see 

[psuhoffman]

3 minutes ago, TSSN+ said:

DC right at the end of the storm. Talk about riding the line.

 

heavy precip is over there...they go to mix during the light precip that lingers after the WAA thump...the dryslot stuff.  DC doesn't actually lose much QPF to mix on this EC run...it was close...but they held the thermals through the crazy heavy precip then warmed immediately after...which is common.  

[Stormchaserchuck1]

Almost a negative tilt over AZ on the NAM at 60hr lol

[mitchnick]

Heights still a little lower than 12z Nam at 57hrs

[psuhoffman]

1 minute ago, Stormchaserchuck1 said:

I'm comparing to the 12z GFS. SW piece isn't cutoff on the NAM at hr57

FYI, when you do analysis of a model run, everyone assumes you are comparing it to its previous run.  If you are comparing it to a different model you have to say that or no one will know what you're talking about...even more than normal.  

[yoda]

60 18z NAM 

 

 

 

[stormtracker]

2 minutes ago, TSSN+ said:

It’s looking less than 12z Nam so far so we will see 

I'm not sure what he's seeing tbh

[stormtracker]

1 minute ago, psuhoffman said:

FYI, when you do analysis of a model run, everyone assumes you are comparing it to its previous run.  If you are comparing it to a different model you have to say that or no one will know what you're talking about...even more than normal.  

This.  That's what I thought he was doing and why I was thinking his analysis is pretty whacked if doing run to run comparisons. 

[TSSN+]

So far less N/S phasing and lower heights out front.