GaWx

Great stuff, Don! Since I had seen similar results in looking at the following for RDU big snows, I figured you and others might find this interesting: 21 RDU 6”+ snowstorms since 1950 (Niña or -neutral ENSO bolded)1/19/1955 Niña neut PNA, neut AO, moderate -NAO12/11/1958 mod +PNA, neut AO and NAO3/2-3/1960 mod -PNA, neut AO and NAO3/9/1960 weak -PNA, strong -AO, neutral NAO2/26/1963 -neutral strong +PNA, mod +AO, neutral NAO1/26/1966 neut PNA, strong -AO and -NAO2/9/1967 -neutral mod +PNA, weak +AO, moderate +NAO3/1/1969 strong +PNA/-AO, moderate -NAO1/7-8/1973 weak +PNA, neut AO, strong -NAO2/18-9/1979 neut PNA/AO/NAO3/1-2/1980 neut PNA/AO, moderate +NAO3/24/1983 mod +PNA/-AO, neutral NAO2/6/1984 -neutral mod +PNA/+AO, strong +NAO1/7/1988 mod +PNA, neut AO, weak +NAO2/17-8/1989 Niña neut PNA, strong +AO/+NAO1/24-5/2000 Niña mod +PNA, neut AO, moderate -NAO1/2-3/2002 -neutral strong +PNA, neut AO, moderate -NAO2/26-7/2004 neut PNA, strong -AO, weak -NAO12/26/2010 Niña weak -PNA, strong -AO, moderate -NAO1/17/2018 Niña neut PNA, weak +AO, strong +NAO12/9-10/2018 mod +PNA, neut AO, moderate +NAO—————————For the 21 storms-11 (52%) +PNA, 7 (33%) neutral PNA, 3 (14%) -PNA-7 (33%) +NAO, 6 (29%) neutral NAO, 8 (38%) -NAOSo, whereas 52% had a +PNA vs only 14% with a -PNA, 38% had a -NAO vs 33% with a +NAOSo, whereas there were almost 4 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been much more balanced.————The above is for all ENSO.What about for just -ENSO?-5 (56%) +PNA, 3 (33%) neutral PNA, 1 (5%) -PNA-4 (44%) +NAO, 1 (11%) neutral NAO, 4 (44%) -NAOSo, whereas 56% had a +PNA vs only 5% with a -PNA, 44% had a -NAO vs 44% with a +NAOSo, whereas there were 5 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been totally balanced. ————— I found similar results for Greensboro and Atlanta. Bottom line: in the SE US, a +PNA is a bigger driver of big snowstorms than is a -NAO.Daily PNA link: https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.pna.index.b500101.current.ascii Daily NAO link: https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.index.b500101.current.ascii ———— *Edit: Interestingly, looking back at big storms at RDU and GSO, the last 5 (2014-18) were all with a moderate to strong +NAO! So, there hasn’t been even one 6”+ snow at either RDU or GSO with a -NAO (even a weak one) since way back on 12/26/2010! This could, of course, be from randomness. But I’m not sure about that considering what @bluewavehas said about -NAO ridges tending to hook up with SE ridges more often than in the past. Hmmmm…. Edit #2: I just noticed this for the 21 RDU big snowstorms for the AO:5 +AO, 11 neutral AO, 5 -AOSo, neutral has been favored.

My best explanation is that the heart of the cold was aimed more toward your SW. Consider that GSP had 22, Macon had 25, and SAV/JAX had historic 28s! But from your area to the NE US, there was little (or no) record cold.

We do way down here, Anthony. Suppression is our winter bread and butter. Therefore, I love +PNAs! Nothing is more beautiful on a wx map than a very tall western N American ridge.

Allan Huffman going with a cold January in the E US. I wonder if this is because of a prog for a very early SSWE followed by a lagged cold effect in Jan: I’d be more than happy with this. I’d love another cold Jan! Not having a warmer than normal La Niña winter in the majority of the SE including another cold Jan would be a victory!

Thanks for posting this. I wonder if Alan’s cold Jan is largely because of a prog for a very early SSWE followed by a lagged cold effect in Jan. I’d be quite content with this. Not having a warmer than normal La Niña winter in the majority of the SE including another cold Jan would be a victory!

Indeed, there’s a much greater % of the conus with BN vs AN in weeks 1-2 of Dec.

Thanks. This is what I was looking at directly from ECMWF rather than from WxBell and also this is strictly for Dec 1-21: still no prevailing +PNA Dec 1-7: coldest MW to Rockies vs mainly NN NE/SE Dec 8-14: coldest MW to N Rockies; slightly cold NE; NN SE Dec 15-21: slightly cold NE, NN SE

Today’s Euro Weeklies for Dec 1-21 are still showing consistent strong cold largely avoiding the E and especially SE due to a neutral PNA to -PNA not driving the coldest anomalies far into the SE. The Midwest to N Rockies are where the coldest anomalies remain concentrated.

AAM is still looking to go back to a solid negative next week and last for 2 weeks. However, afterward, this is showing a move back up closer to neutral for early Dec fwiw:

Natgas is up a whopping 5% due to increased late Nov-Dec cold potential.

The Earth’s average CO2 level was 333 during the very cold winter of 1976-7. That’s pretty impressive considering that it had risen from 285 in 1850. I’m assuming that the increase in sulfates was probably a big reason. To compare, it is now all of the way up to ~431!

This map gives a good perspective that shows the record cold was widespread from the mid-south to the SE US and with a few in the lower Midwest and also in TX although, indeed, none in the NE US:

Followup to the above based on lowest hourlies through 7AM (I’ll update this if any official lows turn out to be lower):These appear to be the lows along with the model that was closest out of the 11/7 6Z GFS/ICON/Euro runs and 11/7 0Z UKMET/CMC runs:SAV: 28/ICONNE ATL: 28/EuroGSP: 23/ICONCAE: 29/ICONCLT: 29/CMCRDU: 30/ICON, Euro, GFS tied-Avg of these: 27.8, which is significantly colder than my guess of 30.5 and lead me to be dead wrong with my prediction of ICON to be the furthest away!-So, although the CMC was closest to only 1 of the 6, it’s average of 28.5 followed by ICON’s 26.3 were closest to the 27.8 actual-UKMET’s 32.6 was easily the furthest-So, ICON, alone, was closest to 3 of the 6So, ICON and CMC did the best overall due to being the coldest while UKMET was the worst due to being the warmest

@donsutherland1put together and posted this excellent table in the SE thread that says a lot about how historic this cold is in the Deep South:

Thanks, Don! To add to this, today’s 28 F at KSAV (SAV airport) was colder than 78% of the coldest official Savannah lows for the ENTIRE November (records back to 1874)! The last time it was colder during the entire November was 2014. Even Hunter AAF base, which is ~6 miles to the SE (closer to the ocean), was able to have a low of 29! So, the ability of this windy freeze (as opposed to it being a radiational freeze) getting the cold all of the way to the coast was quite evident! Also, the official Jacksonville, FL, station (more inland airport) got down to 28! Closer to town lows were 30-32. It looks like various stations in Gainesville, FL, got down to 30-34. The official Gainesville (airport) got down at least to 32. I’m guessing its official low will end up at 31.

My city’s official low (KSAV) as of 7AM EST was way down to 28 F, which beats the 31 record low for the day (records back to 1874). Not only that but also: -last time it was this cold or colder this early in season was 1976 -colder than 78% of coldest for ENTIRE November -last time it was colder in entire November was 2014

This Euro Weeklies run verbatim looks to me like it may be closer to a neutral PNA than a -PNA for the avg of the 3 weeks and especially weeks 1-2 as 3 does look like it may be more -PNA (along with a -EPO, -NAO, and -AO): (not favoring the SE for intense cold and favoring the Midwest over the NE) Dec 1-7: Dec 8-14: Dec 15-21:

You can add Wilmington, NC to that record earliest snow. Their previous record earliest was also 11/12/2013.

The wind here has been crazy high. It was enough to blow over my trash bin on its side, which I don’t recall ever happening before!

WCS accidentally left out the SSWE of 11/30/1958 unless they don’t think 1958 counts as modern: https://www.researchgate.net/figure/The-SSW-and-SFW-event-onset-date-year-and-type-identified-in-the-NCEP-NCAR-dataset-The_tbl1_267063738

That -1.2 is the RONI daily equivalent value, not trimonth, and that seems legit. OTOH, the last released trimonth RONI was -0.78.

My niece in Emory area (NE Atlanta) reported snow flurries just before 5:15PM. She was so excited! Edit: Also two friends in different parts of Cobb County (NW of Atlantic) saw snow flurries/showers this afternoon…one said they lasted a couple of hours with it coming down “pretty good” for a few minutes

Euro Weeklies: coldest run yet for 1st 3 weeks in Dec for US overall. The maps don’t even have a speck of warmer than normal in the entire Conus except for S TX and S/C FL. Dec 1-7: Dec 8-14: Dec 15-21:

What has been the approximate range of total snowfall for Chicago, itself, so far? I know there’s a last gasp now near the shoreline.

ONI: -0.45 NDJ 2024 26.09 -0.53 DJF 2025 26.05 -0.59 JFM 2025 26.49 -0.38 FMA 2025 27.11 -0.18 MAM 2025 27.60 -0.09 AMJ 2025 27.72 -0.11 MJJ 2025 27.54 -0.11 JJA 2025 27.11 -0.19 JAS 2025 26.63 -0.32 ASO 2025 26.31 -0.45 ———— RONI: -0.78 NDJ 2024 -1.07 DJF 2025 -1.12 JFM 2025 -0.90 FMA 2025 -0.67 MAM 2025 -0.52 AMJ 2025 -0.49 MJJ 2025 -0.43 JJA 2025 -0.47 JAS 2025 -0.63 ASO 2025 -0.78 ———— So, RONI less ONI -0.33 RONI less ONI: NDJ -0.54 DJF -0.53 JFM -0.52 FMA -0.49 MAM -0.43 AMJ -0.38 MJJ -0.32 JJA -0.28 JAS -0.31 ASO -0.33 So, after slowly falling NDJ through JJA, RONI less ONI has bounced back some. ONI link: https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt