2020-2021 Winter: Early Thoughts

[k0skinne]

Here is some model prediction provided by Kirk Mellish, WSB 750 AM Atlanta Met ...

Winter snow outlook from a model that did well last winter

If you're wondering whether we'll see snow this year—WSB's Kirk Mellish is digging in on models for a preview of winter weather headed our way.

www.wsbradio.com

 

[Rain Cold]

Here is some model prediction provided by Kirk Mellish, WSB 750 AM Atlanta Met ...

Winter snow outlook from a model that did well last winter

If you're wondering whether we'll see snow this year—WSB's Kirk Mellish is digging in on models for a preview of winter weather headed our way.

www.wsbradio.com

After you escape the gauntlet of pop-up adds, you find that the model still predicts below normal snowfall for the region, though the signal is weaker than last year.

 

[J.C.]

Here is some model prediction provided by Kirk Mellish, WSB 750 AM Atlanta Met ...

Winter snow outlook from a model that did well last winter

If you're wondering whether we'll see snow this year—WSB's Kirk Mellish is digging in on models for a preview of winter weather headed our way.

www.wsbradio.com

That map shows me around 25-30%. I don't know my definite average, but I had 2.5", and areas north had 4-6, which is pretty close to average for most areas in far northern Georgia.

 

[NoSnowATL]

 

[GaWx]

I know you guys like what he’s saying here, I’d love for it to be a reason to be excited, and he’s smart and knowledgeable, but unfortunately being smart and knowledgeable doesn’t mean he can’t also be biased toward cold. In that regard, he seems JBish to me and tends to wishcast cold. Furthermore, he left out that we’re likely going to have a strong La Niña as we’re almost already there. Judah was referring only to weak to moderate La Niña.
Sorry, folks, but as long as we have the very warm west Pacific, the MJO will likely favor the warm phases and the winters will be mainly mild.
Oh I forgot, I’m also a wishcaster per @ryanardo lol.

 

[GaWx]

On second look, he’s apparently mainly only talking about cold portions of these winters, not the entire winters averaged out. Ok, now getting a cold period or two due to the PV disruption this winter? That’s always quite possible even during mild winters dominated by the warm MJO. It is normal to have a cold week or two interspersed even during mild winters. So, hopefully he’s on to something. I mean having one month near or even a little colder than normal is doable.

 

[GaWx]

Hot off the press from Maxar: why are they expecting a mild winter? Actually, they have +2 to +3 in the SE US, which isn't all that warm as it would be significantly colder than last winter. Geez, +2 to +3 is really about the new normal. Big whoop. So, whereas I fully expect the SER to be in charge much of the time (look at it even now), I'm hoping it won't be as dominating as last winter. Regardless, enjoy the wx as that is the only wx you get. (from a wx philosopher most of us know):


"Forecaster Analogs For Winter 2020-2021

19 meteorologists at MAXAR submitted individual winter forecasts, and 17 made use of analog methodologies as part of their reasoning. The table within this discussion are those analogs most common among the forecasters and the reasoning for use. The primary themes among the list are the +AMO (i.e. warm Atlantic), which is represented in eight of the nine analogs, the +WPAC (i.e. warm west-tropical Pacific sea surface temperatures), which is represented in eight of the nine analogs, La Niña, which is represented in five of the nine analogs, and a hotter than normal summer preceding, which is represented in each analog. The AMO was measured at +0.31 in September and is firmly within its multidecadal warm phase. On its own, it correlates warm in winter with a –0.30 anomaly correlation to GWHDDs. Related to the +AMO, waters are anomalously warm in the central latitudes of the North Atlantic, and this is potentially a leading indicator for the also warm correlating +NAO pattern during the winter season. La Niña is currently in a moderate state as of the most recent weekly measures. It is common for convective activity to be enhanced over the west-tropical Pacific, nearby Indonesia, during La Niña winters. That activity will likely be further enhanced over the anomalously warm waters; the WPAC ranked second warmest back to 1950 in September. These are the main forcing mechanisms contributing to the forecast. Four of the top-15 warm winters are among the analog list, while zero years fall into the top-15 for coldest back to 1950. The analogs range from the 2016-17 warm record to the 18th ranked cold season from 2010-11. The weighted average of analogs are spatially similar to the forecast for temperatures, with 2495 GWHDDs also matching the forecast."

 

[Webberweather53]

For those interested and/or if you're still keen on making a winter forecast, I just finished making a major update to my Ensemble Oceanic Nino Index (ENS ONI) that I've had on my website for the last few years and it now includes uncertainty estimates! I also changed from using mean SSTs at all time steps to median values amongst available datasets. This preserves the amplitude of ENSO events prior to 1950 that are being damped by a lack of observations + large inter-dataset spread & makes the ENS ONI more robust to outliers. The choice of using the ensemble median over the mean also better showcases the well known asymmetry in ENSO amplitude, wherein the strongest El Ninos are typically more intense than the strongest La Ninas. I've added the relatively new HADISST2.1 dataset to my analysis (had to create an ensemble mean netcdf file by merging all of the individual ensemble members together). The addition of HADISST2.1 definitely improves the quality of the ENS ONI prior to 1900.


Here's a map of the HADISST2.1 ensemble mean SST anomalies (wrt the 1851-1900 base period) over the tropical Pacific. Anywhere you see deep red are where SST anomalies are >+3C.




Corresponding ENS ONI time series:




Ensemble Oceanic Nino Index (ENS ONI)

 

[Fountainguy97]

Well that escalated quickly. Will level off into November as the NAO goes + and we flip to an overall warmer pattern across the US.

Maybe this record setting October will re-appear into December.

 

[SETNwx]

Hmm, looking 2002-2003 to me:

 

[Ollie Williams]

Look who I found. I guess we’ll see a warm winter.

 

[Rosie]

Look who I found. I guess we’ll see a warm winter.
View attachment 51141
crawling across roads here.

 

[Myfrotho704_]

Look who I found. I guess we’ll see a warm winter.
View attachment 51141

Saw one the same color 3 days ago and lots of people have seen that color

 

[tramadoc]

Look who I found. I guess we’ll see a warm winter.
View attachment 51141

The ones around me in northeast NC are black.

 

[Webberweather53]

I came across this really cool paper that discusses the climatology of long duration (LD) freezing rain (ZR) events in N America. Some very interesting regional climatological tendencies are discussed herein!

Figure 1 is arguably among the most interesting ones in this paper, while the SE US doesn't get a lot of ZR events compared to other areas of N America, we have the highest fraction of long duration (> 6 hr) ZR w/ something in the ballpark of 40-50% of all ZRs lasting longer than 6 hours! The SE US is also unique in that our ZR's tend to have the deepest onset mid-level warm layer aloft, and even more importantly, dew point depressions are also a unique feature of ZR events to our part of N America. You don't tend to see massive low-level dry layers in places like the NE US and southern plains.





The southern plains is interesting in that while they don't see a lot of ZR events, they have the largest proportion of super long (>18 hr) ZRs and unlike the SE US and NE US/SE Canada, their ZRs actually end with a cold frontal passage + cold air advection and the warm nose aloft completely eroding away, whereas it continues to amplify here in the SE US throughout the event.

Figure 6 (shown below) alludes to this apparent discrepancy in the south-central plains as well as highlighting the larger dew point depressions associated w/ SE US ZR.







Composite soundings (with median shown by darker line, IQR is (or 25th-75th percentile of all soundings) for NE US/SE Canada (top), south-central plains (middle), and southeastern US (bottom) for the onset of a ZR event (purple) and ending (red).






Definitely a really cool paper!

https://journals.ametsoc.org/waf/article/34/3/665/344655/Long-Duration-Freezing-Rain-Events-over-North

 

[Webberweather53]

The ones around me in northeast NC are black.

Wall to wall torch

 

[tramadoc]

Wall to wall torch

Yep. That’s what I was told. Brown is cold and black is hot.

 

[Brent]

This almost record cold snap here so early has definitely got me wondering

My concern is we had almost the same thing in November last year and the winter still got a huge F locally *shrugs*

 

[tennessee storm]

This almost record cold snap here so early has definitely got me wondering

My concern is we had almost the same thing in November last year and the winter still got a huge F locally *shrugs*

seems like when winter tries to come late October through November, when we get to the heart of real winter... its a big fail. not sure a good sign to see the cold this early to be honest... already our odds are stacked against us with a fairly strong nina developing... usually winter come early and leave early in moderate to strong nina enso conditions

 

[BIG FROSTY]