Pattern December, Make analogs relevant again

[Webberweather53]

I'd really like to see a deeper, more extensive snow pack in the northern tier of the US leading up to this pattern change for us to score a big winter storm quickly in mid December. Certainly getting the impression (as I mentioned a few days ago) that we'll have to sacrifice a few storms when this pattern change commences before we can truly get in on the action (and we may have to sacrifice a few storms potentially to the Great Lakes, Ohio Valley, Upper midwest, and Northeastern US and mid Atlantic)

 

[GaWx]

What? No ensemble support?

Yes, ensemble support.

 

[ForsythSnow]

No, Mount Pinatubo's aerosols were distributed across the tropics in a matter of 2-3 weeks as noted by Aquila et al. Yes, we all know the volcanic eruption cooled global temperatures but it actually made the subsequent winters of the early-mid 90s that followed much warmer here in the SE US because the radiative imbalances caused by the aerosols in the stratosphere strengthened the mid-latitude westerly jet and polar vortex (+AO). Read my earlier posts for details...

"The sulfate cloud generated by the eruption of Mt. Pinatubo circled around the Earth within 3 weeks of the eruption [Guo et al., 2004; McCormick and Veiga, 1992], crossing the equator and diffusing to mid- and high latitudes in both the northern and the southern hemispheres."
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120002602.pdf

My question is how big of a difference will it make given Pinatubo was in the Northern Hemisphere while Agung is just south of the equator?

 

[Webberweather53]

What? No ensemble support?

Not sure how much more ensemble support you could possibly ask for

 

[Webberweather53]

My question is how big of a difference will it make given Pinatubo was in the Northern Hemisphere while Agung is just south of the equator?

Probably-likely not much of a change, it could certainly change the conduit though which the aerosols get here if it's a southern hemisphere tropical volcano that goes off, the aerosol pathway would be in the mid stratosphere instead of the lower stratosphere (as noted by the aforementioned, linked paper), but the impacts to radiative imbalances generally remain the same

 

[GaWx]

It is hard to imagine a much better ensemble mean at H5 than the 12Z GEFS. Looking at the 12Z GEFS mean's 850/precip maps, there must be some very close calls if not downright good SE hits around 12/11-13, especially for NC and especially 12/12-13. Shades of the great ATL sleetstorm of exactly 100 years ago to the day? Tony's devoted moles' "Sleet for a Week" T-shirts giving us the mojo?!?!

 

[Webberweather53]

Coldest air relative to normals will be over Eurasia the next few weeks we will just have to work with arctic air in our own backyard per say (of North-Central Canada, Alaska, & Greenland origin). Definitely sufficient to get wintry weather here but not quite as good if the air mass was actually of Siberian origin instead, like it was in 2013-14 & 2014-15
View attachment 1594

If however, as advertised by the GEFS suite, a large ridge begins to go up over Alaska and the Bering Sea and retrogrades into northeastern-northern Eurasia, (which is the climatologically favored pattern in a WQBO/NINA regime), then the "Siberian Express" will come calling in our neck of the woods just after mid month as cross polar flow seeds North America with exceptionally cold, Siberian air. This height configuration would also increase the chances Miller B/overrunning events as opposed to big Miller A/coastal threats which will probably be relatively more prevalent in the earlier portions of the period when the Greenland/Baffin Bay block is dominant.

 

[Webberweather53]

It is hard to imagine a much better ensemble mean at H5 than the 12Z GEFS. Looking at the 12Z GEFS mean's 850/precip maps, there must be some very close calls if not downright good SE hits around 12/11-13, especially for NC and especially 12/12-13. Shades of the great ATL sleetstorm of exactly 100 years ago to the day? Tony's devoted moles' "Sleet for a Week" T-shirts giving us the mojo?!?!

I would definitely take another storm like what we observed in December 1917 in a heartbeat

 

[GaWx]

I would definitely take another storm like what we observed in December 1917 in a heartbeat
View attachment 1601

Believe it or not, that was the last major Dec SN and/or IP storm for Atlanta!! Talk about overdue. Wouldn't it be something if they finally were to get the next one EXACTLY 100 years later?!?! They've had a good number of major Dec ZR storms since then but not major Dec SN or IP. I'm not predicting that by any means but IF the 12Z GEFS maps were to verify fairly well, the SE is liable to be threatened by a major winter storm around 12/12-13. But since that is still soooo far away, the odds are still low at this very early stage.

 

[Webberweather53]

OTD in 1950...


ECMWF 20th Century Reanalysis (ERA-20C) 500 hPa height (contours) & relative vorticity for 9z November 25 1950


ERA-20C MSLP (contours) & 1000-500 hPa thickness (shaded) overlaid w/ fronts for 6z November 26 1950

 

[dsaur]

Yes I am. So, just as the moles and you want your week of sleet (I love that the moles are so devoted to try to get you a weeklong sleet...that's fantastic), I want my near miracle. I tell
myself that if it can snow here multiple inches in cold neutral winters like 1989-90 and 1967-8, then by golly it can snow multiple inches in a weak to mod La Niña!

I'm pulling for you, my friend! A Dec Sav snow would be one to talk about when the next Larry is giving historic facts in 100 years, lol. I wonder if he will use an abacus too?

 

[Webberweather53]

OTD in 1950...

View attachment 1608
ECMWF 20th Century Reanalysis (ERA-20C) 500 hPa height (contours) & relative vorticity for 9z November 25 1950
View attachment 1603

ERA-20C MSLP (contours) & 1000-500 hPa thickness (shaded) overlaid w/ fronts for 6z November 26 1950
View attachment 1602

View attachment 1607

View attachment 1606

View attachment 1604

Temperatures in Atlanta, GA bottomed out at 3F on November 25 1950, with a high of only 17F recorded that same day. Absolutely absurd for November... Even down to Macon, GA a high of 26F and low of 10F was recorded w/ a dusting of snow lol

 

[GaWx]

KATL somehow got down to THREE degrees on 11/25/1950!!!! That's not a typo! I consider that to be among ATL's most amazing temperature records for any time of year. I wouldn't be surprised if Nov hasn't seen anything colder there in many hundreds of years.

Edit: I didn't see Webb's post just above this when I was posting this.

 

[dsaur]

I remember the sleet storm in ATL in 1979, official was 4" but some unofficial total were closer to 6"..

One of my top 2 favorite storms was that one, and one in the early 60's, late 50's. It doesn't get any better than that one!! Even if it sleeted for a week, it would have to go a long way to beat that one.

 

[whatalife]

It is hard to imagine a much better ensemble mean at H5 than the 12Z GEFS. Looking at the 12Z GEFS mean's 850/precip maps, there must be some very close calls if not downright good SE hits around 12/11-13, especially for NC and especially 12/12-13. Shades of the great ATL sleetstorm of exactly 100 years ago to the day? Tony's devoted moles' "Sleet for a Week" T-shirts giving us the mojo?!?!

Some really close calls for the SE on the 12z GEFS for the time period you mentioned. It will be interesting to see how this trends.

Sent from my iPhone using Tapatalk

 

[dsaur]

Believe it or not, that was the last major Dec SN and/or IP storm for Atlanta!! Talk about overdue. Wouldn't it be something if they finally were to get the next one EXACTLY 100 years later?!?! They've had a good number of major Dec ZR storms since then but not major Dec SN or IP. I'm not predicting that by any means but IF the 12Z GEFS maps were to verify fairly well, the SE is liable to be threatened by a major winter storm around 12/12-13. But since that is still soooo far away, the odds are still low at this very early stage.

Need some rain, Larry. That always worries me about abundant cold....if usually has abundant dry air too, lol. Oh, well, we only get anything here thu timing, so we'll have to time in some moisture to go with the cold. One encouraging thing to note, is I've had very few rain chances lately, but they've given me an inch, or more, most of them, so that would work nicely with some bitter cold, A nice gom low coming up into cold air in place could provide the start to my week of sleet

 

[Brick Tamland]

Some really close calls for the SE on the 12z GEFS for the time period you mentioned. It will be interesting to see how this trends.

Sent from my iPhone using Tapatalk

Yes, looks more positive right now than not heading into December.

 

[GaWx]

Temperatures in Atlanta, GA bottomed out at 3F on November 25 1950, with a high of only 17F recorded that same day. Absolutely absurd for November... Even down to Macon, GA a high of 26F and low of 10F was recorded w/ a dusting of snow lol

Even way down here near the coast, the high was only 32 on 11/25/1950!! One has to go all the way to 12/23 for the next earliest high of 32 or lower! That was during the great SE coastal snowstorm of 1989. There was also a T of SN here on 11/24/1950.

 

[Webberweather53]

Comforting to see a nice 375-380m anomalous mid-upper level ridge over Greenland near initialization... Should be pretty obvious by now this pattern is already capable of producing monstrous blocking highs in the North Atlantic

 

[WeatherWatch]

Well, what about Mount Tambora? that erupted in 1815 and was followed by extremely cold spring and summer in Europe of 1816. Also, Europe had snowfall in June, July and August. It was known as, "the year without summer." I tried to find an H5 height map but I don't think those maps existed during that time. But since Europe was unusually cold, the eastern US probably was as well.

Then there's Krakatau, which erupted in 1883 that generated 20x the amount of volcanic matter released by Mt. St. Helens in 1980. After the eruption, the world experienced unusually cool weather.

Both of those volcanoes are in Indonesia, just like Mount Agung.

Sent from my SM-J327T1 using Tapatalk