GaWx

We finally made it to the climo coldest day in the Arctic, Feb 25th (per blue line):

All I’m saying is that the MJO is forecasted by most models to be in either phase 1 or 2 in early Mar, which on average have been cooler than normal (especially the coldest phase on avg, 2): Those are only averages. So, it could easily end up not BN. The other indices (including EPO) say that a strong cold push or multiday period of BN in the SE US in early Mar will be a challenge though of course not impossible, especially in NC based on model progs. Even if it is BN for a few days then, that’s of course far from meaning a NC snowstorm outside of the mountains is likely. It is important to realize that although the Euro Weeklies have done pretty well this winter, the Euro ops have had a cold bias overall, especially beyond 5 days. Remember the many Euro Barney outbreaks that ended up being no more than a Dino? That’s despite the actual cold outbreaks we had.

This Barney snow machine on day 11-12 on the 12Z Euro is of practically no forecasting value. Also, the Euro op has been too cold on many runs this winter, regardless, with numerous false Barneys. This is nothing more than entertainment that far out. The forecasts for indices like PNA, AO, and NAO actually favor warmth. The MJO though is forecasted to be in cool phases fwiw.

We’re on the way to a top 3 CPC +PNA Feb since 1950 with top 2 possible. The only one that appears safe is the +2.04 of 1977. 1980’s +1.74 is 2nd. Both of those were El Niños. I’m projecting something within +1.55 to +1.9 for 2/2025. In 3rd is 2016’s +1.48, another El Niño. The highest Feb on record during La Niña is 2000’s +1.12. 2024-5 is on track to be at least very close to the highest on record for DJF. Right now I have it being +1.42 to +1.53 with +1.46 to +1.50 most favored. The current highest is 2015-16’s +1.43 followed by 1976-7’s +1.41 (both El Niño). The highest on record for La Niña is only +0.89 (2000-1). That will be obliterated!

I may be a bit unusual for a wx enthusiast in that in addition to a good winter as well as some other things, I also enjoy relatively uneventful (what many weenies consider boring) comfortable wx for walking or even just sitting in my BY. Although severe wx is certainly exciting, I don’t actually hope for it due to risks to lives/property. Being a homeowner in normal wx is enough of a headache. I especially fear tornadoes. I’ve never in person actually seen a funnel, not even a water spout! I’d like that to continue lol. Looking ahead, it still looks like a SE cooldown and freeze in much of NC is possible on 3/2. Otherwise, it looks like a mix of mainly NN and AN into early Mar before it possibly becomes more consistently AN. This is despite the MJO being in cooler than average phases for late Feb/March.

Despite this, a rather chilly period is on the way for Mar 2-4 with 2 cold nights and 2 cool days, especially up in NC/upstate SC/N GA.

The Euro Weeklies, though far from perfect especially for further out weeks, have done pretty well overall this winter from a few weeks out with the temperature anomalies. They called pretty well the late Nov/early Dec chill, the warmup that followed, the Jan cold, the late Jan/early Feb warmup, and the cold in mid Feb that followed that though they earlier had mid-Feb as mild. So, mid-Feb cold wasn’t seen as far out as some other periods. Could they be wrong especially in weeks 4-6? Absolutely, of course.

Today’s Euro Weeklies: mild to warm all weeks NG down to 3.96

Today’s Euro Weeklies: mild to warm all weeks

N Hem ACE (excluding N Indian, which isn’t available): 1991-2020 averages: Atlantic 110, EPAC 135, WPAC 330; Total: 575 Last 15 years total ACE for these 3 basins: 2024: 454 2023: 579 2022: 373 2021: 449 2020: 406 2019: 506 2018: 813 2017: 494 2016: 587 2015: 816 2014: 546 2013: 388 2012: 533 2011: 436 2010: 338 ————— AVG 2010-24 ACE: 515 (60 below 1991-2020 avg) 2010-24: 8 BN, 5 NN, 2 AN So, the average of the last 15 years has actually shown a decrease in ACE vs 1991-2020 avg in the ATL/NPAC and has had more BN than AN seasons. Also, during the last 3 years of FL getting hit quite hard with 6 H/4 MH, Atlantic and NPAC ACE has averaged only 469 (106 below 1991-2020). During the last 9 years of FL getting hit hard overall (10 H/7 MH) and the warmest global temps/tropics, ACE has averaged 518 (57 below 1991-2020) with 5 BN, 3 NN, and only 1 AN. https://en.m.wikipedia.org/wiki/Accumulated_cyclone_energy

Indeed, a large part of the problem is that more are on the coast than in 1921-50. But what if we’re about to start a quiet cycle and the next 10 years are quiet in FL? Would we be hearing nearly as much about this in, say, 2035, as we are in 2025? I bet we wouldn’t be. Keep in mind that the NH overall has actually been quieter recently per ACE!

But I fully believe in CC. It’s just that certain aspects of wx are made worse in certain locations due to the bad portion of cycles that have been around a long time/nothing new. Not everything is due to CC. Some of it is natural cycles of wx. And these cycles are often not acknowledged by the media due to ignorance. Plus the media wants ratings. So, they want their stories to sound dire. Politicians, who are largely ignorant, are vulnerable to this, also. They often follow the money, whatever “side” they’re on.

-FL had 7 MH and 3 other H over just the last 9 seasons. Over just the last 3 years they’ve had 4MH and 2 other H. Terrible! -But over just the 2 years 2004-5, FL had 5 MH and 2 other H! That was arguably much worse since there were more over a shorter period. But then there were no H 2006-15! -Over the 7 years 1944-50: FL had 7 MH and 4 other H! Over just the 4 years 1947-50, they had 5 MH and 2 other H! So, this period was pretty comparable to the most recent. But then there were no MH 1951-9. -1921-50 overall was a bad 30 year period for FL with 14 MH, an average of nearly one every two years. We’ve had 13 over the last 30 years…comparable but not worse and thus not the worst on record. -So, as terrible as the last 3 years have been in FL, it was as bad or worse 2004-5 and 1947-50. FL getting hit very hard is nothing new. And then each of those 2 periods had no MH for the subsequent 10 and 9 years, respectively. So, these devastating seasons tend to run in cycles. So, what feels like a dire situation (“sky is falling”) may very well be followed by a long period of quiet. Fingers crossed! There have been dire periods before. The SE US in general is due a quiet period.

For no snowstorm of 4”+, the highest total season’s snowfall I could find was 14.4” in 1871-2.

Today’s Euro Weeklies suggest that the winter is nearly over. What I mean by that is no week-long period of BN temp signals for most of the E US. Other than New England being NN 3/3-9 and FL being BN to NN the first 3 weeks, the rest of the weeks are dominated by AN temp signals.

Today’s Euro Weeklies suggest that (wind reversal or not in mid March) that the winter is nearly over. What I mean by that is no week-long period of BN temps for most of the E US. Other than New England being NN 3/3-9, the rest of the weeks are dominated by AN temp signals outside of FL the first 3 weeks.

I should add that if there is a reversal in mid March, I’m not saying it couldn’t end up being a FW since several FWs have occurred that early per what you said and the FW table I just posted. ~1 in 12 FWs since 1958 have occurred by Mar 13th. Some of the ensemble members appear to be FWs as they don’t come back up to the 0 line. We’ll no more as get closer to the possible wind reversal and the ensemble members start converging. Right now they’re all over the place.

Unfortunately I had forgotten that the daily SOIs go back only to 1991: 3/13/1993: -9 3/12/2022: +16 So this tells me nothing.

I’m ok if you’d like to copy and paste my post in the TN Valley subforum and give me credit for putting it together. Thanks.

YW. I’m next going to check the SOI. Although I already checked the seasonal ENSO and found no tendency, I didn’t check the daily SOIs for each storm.

Thanks for bringing this up! The average date of the final warming is not for a full month after this potential SSW. It is on Apr 12. The average is actually later when there is a very late wind reversal that isn’t a FW. I’ll now look at the years with the 6 latest major SSWs and compare to the final warmings per the chart below. (I’ve never done this. So, this will be interesting): https://wcd.copernicus.org/articles/2/453/2021/#:~:text=Every spring%2C the stratospheric polar vortex transitions,known as the “final stratospheric warming” (FSW).&text=In the NH%2C the median date of,hPa and 15 April at 50 hPa. 1. 1965: SSW 3/25; FW 4/19 2. 1969: SSW 3/13; FW 4/13 3. 1971: SSW 3/20; FW 4/24 4. 1988: SSW 3/14; FW 4/6 5. 2000: SSW 3/20; FW 4/9 6. 2010: SSW 3/24; FW 4/30 So, after each of these 6 very late SSWs/wind reversals, the mean 60N 10 mb wind unreversed for a period til the final warming. For example: -2010’s very late reversal ended ~3/26, which was 5 weeks before its 4/30 FW: -2000’s very late reversal ended ~3/22, which was 2.5 weeks before it’s 4/9 FW: The other 4 very late reversals all ended ~3-4 weeks prior to the respective FW. So the answer to your good question is “no”.

Thank you, Charlie. What you say makes sense. I didn’t post this to take sides but rather am presenting this as something to elicit good discussion since this kind of thing (evaluating all hypotheses) is a vital part of the scientific method. I need to add the following from Viterito that I had originally left off the original post to keep it from being too long: ——————— Here is a comprehensive bibliography on the impacts of geothermal flux on the thermohaline circulation: Thompson L, Johnson GC (1996) Abyssal currents generated by diffusion and geothermal heating over rises. Deep Sea Research Part I: Oceanographic Research Papers 43(2): 193-211. Downes SM, Hogg AM, Griffies SM, Samuels BL (2016) The transient response of Southern Ocean circulation to geothermal heating in a global climate model. J Climate 29(16): 5689-5708. Adcroft A, Scott J, Marotzke J (2001) Impact of geothermal heating on the global ocean circulation. Geophys Res Lett 28(9): 1735-1738. Hofmann M, Morales Maqueda MA (2009) Geothermal heat flux and its influence on the oceanic abyssal circulation and radiocarbon distribution. Geophys Res Lett 36(3): L03603. Urakawa LS, Hasumi H (2009) A remote effect of geothermal heat on the global thermohaline circulation. J Geophys Res Oceans 114: C07016. Mullarney JC, Griffiths RW, Hughes GO (2006) The effects of geothermal heating on the ocean overturning circulation. Geophys Res Lett 33: L02607. Scott JR, Marotzke J, Adcroft A (2001) Geothermal heating and its influence on the meridional overturning circulation. J Geophys Res 106(C12): 31141-31154. Patara L, Böning CW (2014) Abyssal ocean warming around Antarctica strengthens the Atlantic overturning circulation. Geophys Res Lett 41(11): 3972-3978 Emile-Geay, J. and Madec, G. (2009) Geothermal heating, diapycnal mixing and the abyssal circulation, Ocean Sci., 5, 203–217, https://doi.org/10.5194/os-5-203-2009, 2009. Purkey, S. G., and G. C. Johnson, 2010: Warming of global abyssal and deep Southern Ocean waters between the 1990s and 2000s: Contributions to global heat and sea level rise budgets. J. Climate, 23, 6336–6351, doi:10.1175/2010JCLI3682.1. Purkey, S. G., and G. C. Johnson, 2012: Global contraction of Antarctic Bottom Water between the 1980s and 2000s. J. Climate, 25, 5830–5844, doi:10.1175/JCLI-D-11- 00612.1. Mashayek, A., Ferrari, R., Vettoretti, G., & Peltier, W. R. (2013). The role of the geothermal heat flux in driving the abyssal ocean circulation. Geophysical Research Letters, 40(12), 3144-3149. Park, Y.-G., J.-H. Park, H. J. Lee, H. S. Min, and S.-D. Kim (2013), The effects of geothermal heating on the East/Japan Sea circulation, J. Geophys. Res. Oceans, 118, 1893–1905, doi:10.1002/jgrc.20161. Downes, S. M., Sloyan, B. M., Rintoul, S. R., & Lupton, J. E. (2019). Hydrothermal heat enhances abyssal mixing in the Antarctic Circumpolar Current. Geophysical Research Letters, 46, 812–821. https://doi.org/10.1029/2018GL080410 Ballarotta, M. et al., (2015), “Impact of the oceanic geothermal heat flux on a glacial ocean state”, Climate of the Past Discussions, 11, 3597-3624. Jowan M. Barnes, Miguel A. Morales Maqueda, Jeff A. Polton, Alex P. Megann, Idealized modelling of ocean circulation driven by conductive and hydrothermal fluxes at the seabed, Ocean Modelling, Volume 122,2018, Pages 26-35, ISSN 1463-5003, https://doi.org/10.1016/j.ocemod.2017.12.005.

Range for major SSWs since 1958: Nov 28th (in 1968) to Mar 24th (2010). Six of the 44 in the list below occurred anywhere from around the time this one would possibly occur to 3/24. The very late ones had no effect on met. winter obviously since it had already ended. However, the Mar ones can cool a portion of early to mid met spring in the E US. They usually do that 2+ weeks later. A chilly spring doesn’t necessarily mean a snowstorm. There are many aspects of wx forecasting that have nothing to do with snow or extreme cold. https://en.m.wikipedia.org/wiki/Sudden_stratospheric_warming

Here’s the next day’s 0Z extended GEFS update (2/22/25 run, which is latest til tonight) with a much weaker mean SPV per 60N mean zonal winds at 10 mb due to a doubling from 6 members (out of 30 or 20%) with a major SSW 3/9-16 to 12 members (40%). The prior run’s (2/21/25 run) mean dipped only down to +20 on 3/15. This most recent run’s mean dips down to +4:

Now that the “official” MJO has been put on the diagram for 2/19-20 (it takes a few days), I see that it actually wasn’t weakening moderate phase 8 like I thought. It was instead weakening moderate phase 7 (barely off the border with phase 8). I’ll edit my original post to reflect this: