November 21-23, 2023 | NE Winter Storm Potential

[Penn State]

On Thanksgiving Eve.. Wednesday, November 24th, 1971.. a major winter storm was brewing for the Mid-Atlantic and Northeast. The Sentinel, a newspaper publication from Carlisle in Cumberland County, Pennsylvania covered this story in this article. According the article, the resident meteorologists at the Sentinel forecasted a couple of inches of snow for Thanksgiving; however, folks around the region experienced 1 to 2 feet of snow instead. Reporting indicates it was a heavy, wet snow.. one that unfortunately damaged trees and other structures. So.. here’s where I like to connect history and analog; alas, there is no connection to be made other than the coincidence of the holiday. There’s nothing wrong with a good ol’ fashioned surprise though, so hopefully history will repeat in terms of a White Thanksgiving, without any of the damage experienced 52 years ago. 

Alright.. so who’s queuing up the Christmas music in early November? 🙋‍♂️lol.. Maybe Michael Buble can do a rendition of Bing Crosby’s classic, “I’m Dreaming of a White Christmas”.. but for Thanksgiving 🍗 in ‘23. Anyways.. let’s see what the models are serving up. According to the GFS the table is set with an injection of cold air, a lingering area of high pressure over SE Canada, and a low pressure carving through the central United States. It looks as if a transfer occurs, and that low cooks, serving a Thanksgiving feast for folks in the Mid-Atlantic and Northeast. Puns intended 😂. 

In terms of support.. the ensembles of the GEFS and EPS look most promising with clusters of MSLPs south and east along the coast. The CMCE provides dissent, with very little in the way of clustering to the south and east. The operational models follow suit, with the GFS and ECMWF providing support, and the GDPS in dissent. In general.. it does seem that the injection of cold air is being modeled quicker and stronger, which is a necessity for snow this time of the year. Teleconnections are a mess.. and the case could be made that this will exhibit a classic case (-AO, -NAO, and +PNA), though the case can be made for the exact opposite as well. The MJO is favorable.. Phases 7, 8, and 1 are where you want to be at least. I’ll also note the 500mb looks energetic. Climatologically, a snowfall is plausible for interior parts of the NE; however, I wouldn’t call this probable at the moment. For lower elevation of SC and SEPA.. this is quite the long-shot, but it has happened before, and can happen again!

Happy Tracking! 🤓

18z GFS | Hours 174-246

18z GEFS | Hour 210 

WPC Forecast | Day 7 

Spoiler

Surface
12z GFS | Hours 180-252

12z ECMWF | Hours 180-240

12z GDPS | Hours 180-240

Ensembles 

12z GEFS | Hour 216

12z EPS | Hour 228

12z CMCE | Hour 204

500 MB 
12z Comparison | Hour 216 

Teleconnections 

AO 

NAO

PNA

MJO 

BSR for November 22nd 

CPC 6-10 Day Analog 

 

Edited November 17, 2023 by Penn State

[Pghsnow]

Here is the GEFS for that timeframe 

[Penn State]

17 minutes ago, Pghsnow said:

Here is the GEFS for that timeframe 

I’ll take members #5 and #23.. FTW! 

[Penn State]

All the models are cookin’.. 

JMA 

ICON

NAVGEM

UKMET 

[1816]

I'll say this much.. it's nice to have a thread or two going again. 

[Penn State]

6 minutes ago, 1816 said:

I'll say this much.. it's nice to have a thread or two going again. 

I agree. It’s a little early for a thread.. but it’s fun, gets the discussion going. Plus, there’s no expectations this early in the season. 

[WeatherFlash]

Ah tis the season again. Boy did guidance swing from above normal Thanksgiving temps to below normal for the time period. (Eastern half of conus) 

Edited November 14, 2023 by WeatherFlash

[ionizer]

not seeing anything good for NJ

[MaineJay]

EPS suggests a bit of a cutter, but a chance for this to redevelop at the coast.

East Asia more or less agrees.  Departing high pressure may not be able to force this to the coast.  Long way to go, but this may be a storm for our Midwest and OHV friends.

[MaineJay]

Machine learning models.

Info here

https://www.ecmwf.int/en/forecasts/dataset/machine-learning-model-data

lsl 1.66

[Penn State]

GFS sort or lost it at 06z.. but is back at 12z. Parts of the interior would see something at least. Canadian is still very warm.. but with lots of precipitation, albeit rain lol 

[Penn State]

Plus.. if the UK is any indicator, the ECMWF should be fun in about an hour! Probably too warm.. but that’s a good look I believe. 

[Pghsnow]

Following this one its back to back storms in 24 hours. 27th & 28th Great for Ohio at this time.

[Pghsnow]

[Pghsnow]

12z EURO not buying in yet. EPS looks much better

Edited November 14, 2023 by Pghsnow

[Penn State]

12 minutes ago, Pghsnow said:

12z EURO not buying in yet. EPS looks much better

I was a little surprised after I saw the UK. The EPS definitely looks better, as the members sort of split. There's a cohort that transfer to the coast, but the majority still seem to cut N and W. In my mind.. it's all about the high. If the high has the right placement and doesn't just scoot off, that drives the storm. Low has to dig south too. Hour 144 on about all of the models is a good tell at the moment. 

[Penn State]

As we wait on the 18z GFS.. I saw this on Twitter.. Times, they are a changin’

[1816]

39 minutes ago, Penn State said:

As we wait on the 18z GFS.. I saw this on Twitter.. Times, they are a changin’

This is actually pretty fascinating. The way AI learns, it's not far fetched to expect advancements in weather prediction to move forward at amazing pace now. 

[Pghsnow]

[Penn State]

14 minutes ago, Pghsnow said:

That’s a Pittsburgh Special right there! 

[Hiramite]

2 hours ago, Penn State said:

As we wait on the 18z GFS.. I saw this on Twitter.. Times, they are a changin’

Here’s just one of many articles that came out today that provides more detail.  As Spock and 1816 say, “fascinating “.

https://www.wired.com/story/google-deepmind-ai-weather-forecast/

[Penn State]

I was just looking at the CPC 6-10 Day Analogs.. December of 2002 is rising on the charts. There was a pretty good snowstorm around December 5th of ‘02. Here’s a link to some information, maps, and data. Below is the analog. Might set up well for just after this period TBH. 

[1816]

1 hour ago, Hiramite said:

Here’s just one of many articles that came out today that provides more detail.  As Spock and 1816 say, “fascinating “.

https://www.wired.com/story/google-deepmind-ai-weather-forecast/

This is the biggest key in my opinion: "Matthew Chantry, who works on machine learning forecasting at the ECMWF, says that Google DeepMind’s GraphCast has emerged as the strongest of the AI contenders. “Over time it will consistently be just a little bit better,” he says."

It mentions in this article how even ai missed the bus on Otis. As well as some other shortcomings. But when you have a system that can dive into every facet and angle and literally learn from its mistakes, the sky is the limit for improvement. 

[Penn State]

18z GEFS looks nice.. 24 hour mean snowfall does too for the interior. 

[Penn State]

WPC Forecast.. NWS seems to be favoring a blend of the GFS and ECMWF. Discussion below.