GaWx

Followed by a late winter?? Anyway, nothing is certain in the wild and whacky world of wx! Just when you think you've got it figured out, in comes a knuckleball.

I had been hoping that the Euro idea of the MJO going into the circle (which typically wouldn't be a warm signal) before reaching phases 4/5 (which is what GEFS had) would occur in Feb. But it looks like GEFS idea, which favors warmth at midmonth, will win out as the Euro has been inching to the GEFS. Also, the progged +NAO/AO aren't favorable for cold.

Below is a graph showing that the 10 mb winds at 60N dropped sharply from 50 m/s on 1/23 to 12 m/s on 1/28. It needed to drop to <0 to be counted as a "major" SSW. Instead, I expect it to called a "minor" SSW. The models did a good job as they had it drop to this vicinity for a good number of days prior to 1/23. Does it going 75% of the way mean it will still likely have significant cooling effects on the SE starting mid to late Feb and lasting at least a couple of weeks thanks largely to a new long period of -AO? I don't have a good feel for it as the analyses were based on major SSWs. And the model consensus is forecasting some restrengthening of the SPV along with cooling back a good bit in early Feb.

Followup: The 12Z GFS is the coldest yet for NYC and vicinity. However, most of the rest of the models weren't as cold as at the 0Z runs.

Per Tarboro records, there was only a trace of snowfall in Jan of 2001 and that fell on the 9th. After that, the rest of the month was very dry and averaged slightly AN with temperatures. So, with Tarboro being only 10 miles away, I see no way that Conetoe got anywhere near 16" of snow in mid to late Jan of 2001.

The 0Z Euro/UK didn't back off at all in regard to the progged extremely cold airmass for next weekend in the NE. 850s once again get down to near record territory for the lower 48, close to -40C! NYC once again gets down to below 0 on 2/4! We'll see if this holds up in future runs. Also, this Euro was significantly colder in the SE vs the prior run. Edit: This as modeled is a historic cold airmass in the NE and it has been trending colder and colder even down into the SE at the bottom of it. Example: dewpoints over the last 5 Euro runs have dropped 30-50 F for 2/4 at 12Z! There's no telling whether or not this colder trend for next weekend will continue. But if the trajectory of this airmass were to shift more in our direction, it could trend a lot colder. Something to watch!

Followup: 1) The 18Z ICON at 120 suggests that the maps for late week would likely have been colder than the 12Z in the NE. 2) The main reason for this post is the 18Z EPS 144 (end of run), which is significantly colder than the 12Z EPS 150 in the Midwest/NE and is absolutely frigid in SE Canada. Will 0Z runs back away, maintain, or be colder than earlier runs? We'll know soon. Edit: 0Z ICON is much colder than the 12Z in the NE US next Saturday with a deeper plunge of the extremely cold SE Canada high! Also, that leads to a colder SE vs the 12Z due to much stronger wedging.

More on how cold next weekend's airmass might be in the NE, which would be relevant to how cold the SE may get via wedging: For the record (not because I believe it though it will be interesting to follow), the 12Z Euro has -2 at LaGuardia at 168! That would be the coldest there since the -3 of 1/19/1994. But that's very likely going to verify too cold being that it is an extreme operational run at day 7 and there has been a cold bias with models overall. To show how extreme this run was, it had +10 there on the 0Z and low 20s on yesterday's 12Z. To compare for the 12Z runs, the UKMET has +6, GFS +18, CMC +19, and ICON +23. The 18Z GFS is much colder than its prior run and has +6. This extreme Euro run has -40C at 850 mb then in N ME, which would not be far from the coldest on record in the lower 48/just above the coldest in the Midwest for the 1/1985 extreme outbreak. The CMC also has -40C while the UKMET has -39C and the JMA has -37C. The 12Z GFS has it down "only" to ~-31C. Regardless of the likelihood that the 12Z Euro is overplaying the degree of cold at the surface, there may very well end up being the coldest air in a good number of years in the NE a week from now.

For the record (not because I believe it though it will be interesting to follow), the 12Z Euro has -2 at LaGuardia at 168! That would be the coldest there since the -3 of 1/19/1994. But that's very likely going to verify too cold being that it is an extreme operational run at day 7 and there has been a cold bias with models overall. To show how extreme this run was, it had +10 there on the 0Z and low 20s on yesterday's 12Z. To compare for the 12Z runs, the UKMET has +6, GFS +18, CMC +19, and ICON +23. The 18Z GFS is much colder than its prior run and has +6. This extreme Euro run has -40C at 850 mb then in N ME, which would not be far from the coldest on record in the lower 48/just above the coldest in the Midwest for the 1/1985 extreme outbreak. The CMC also has -40C while the UKMET has -39C and the JMA has -37C. The 12Z GFS has it down "only" to ~-31C. Regardless of the likelihood that the 12Z Euro is overplaying the degree of cold at the surface, there may very well end up being the coldest air in a good number of years in the NE a week from now.

The coldest of the winter to date by a good margin is going to be close to, if not in, the NE possibly down to NYC a week from now (2/4) per the 12Z consensus. Something to watch to see how strong of a wedge, if any, would then get the low level cold into the SE. The 12Z Euro is the coldest run yet next weekend in much of the SE with hard freezes at least down into NC. The GFS combines this strong NE cold with moisture to yield wintry precip in the main Carolina CAD region. The PNA has trended toward a decent + for next weekend. Edit: the 12Z Euro has the coldest in Boston and Hartford since at least 2016!

The 12Z Euro's H5 SE ridge, when centered over the FL Strts late Wednesday morning is up at a whopping ~593 dm, the strongest yet for it on any of its runs.

I promise you that you'll survive. I've seen snow only once (for ~two hours) in over 7 years and was frankly lucky to see that. I'm alive and well! What doesn't kill you makes you stronger. I still enjoy winter a lot more than any other season because of the larger variability as well as higher % of lower dewpoint days making it more ideal for me for outdoors. And I can always dream of seeing another miracle snow whether it be this winter or some winter down the road. Meanwhile, I'm still hoping for another cold period later in Feb. As a matter of fact, La Niña/cold ENSO is (perhaps surprisingly) more conducive in Feb/March to an extreme cold shot into the SE than warm ENSO despite being warmer overall than El Nino per recent research I did going back to 1800s. I may share this later. A bit counterintuitive imo.

The 18Z GFS has almost pure snow for much of NC and has the heaviest snow there in many runs!

Absolutely, desperate times, indeed! But at least I'm not throwing the NAVGEM or CFS. And the big difference starts before day 7. At 168, the lowly regarded JMA has the 850 0C line 300-400 miles S of the others. Also, where the others have the 0C line then, the JMA has -10 to -15 C.

Starting at 144, one can see how different the 12Z JMA is vs all of the other 12Z runs with the southern lobe of the TPV further south resulting in colder air moving much further south into the S Plains. At 168 you can see how much colder it is in the SE with troughing to the Gulf coast along with an Arctic high bringing much colder air in vs the SE ridge hanging on all of the others. This is deep cold as opposed to shallow cold from CAD. I'm assuming the outlier JMA is going to end up wrong based on it largely being an inferior model, but thought it was worth documenting this in case it were to score an upset win.

The 0Z GFS/GEFS are mainly warmer in early Feb than prior runs as the SE ridge dominates.

The 0Z Euro is the opposite of the prior run as noted above and instead the freezer door is open late deep down into the SE! But as always, take with a huge grain that far out and we'll see what the next few runs show as well as the EPS.

Don, I thought you might find this interesting. I posted it in the SE forum: Longest -AO streaks back to 1950 along with RDU temperature anomaly 12/25/1959-4/4/1960: 102 days/ 5 BN 2/2-4/11/1958: 69 days/ 6 BN 2/5-4/9/2013: 64 days/ 4 BN 12/23/1962-2/23/1963: 63 days/ 6 BN 11/23/2022-1/23/2023: 62 days/ 3 AN The recent -AO streak apparently ended yesterday at 62 days. What's very notable is how much warmer it has been in the SE US vs during other very long -AO streaks with an anomaly of +3 at RDU vs the other four having had anomalies of a very cold -4 to -6! And on top of that, I'm using updated 30 year normals in the calculations, meaning a warmer normal for the current streak.

Well, the good (from a cold lover's standpoint) and not so surprising news is that the 12Z EPS mean says that the operational is drunk with its SE warmth late in the 6-10. Also, other than a little bit of can kicking, EPS retained its chill of prior runs and actually is slightly colder than prior runs in much of the 11-15.

If you were hoping for a Euro run with implications for cold to dominate the SE in early Feb, the just out 12Z isn't the run for you as the SE ridge holds the cold back. Prior runs looked better, especially yesterday's 12Z. And this isn't a surprise based on the frequent overzealousness of models bringing cold to the SE this winter. But then again, there's the usual high uncertainties with operational runs out past a week or so. So, take with a grain as it is still early.

Longest -AO streaks back to 1950 along with RDU temperature anomaly 12/25/1959-4/4/1960: 102 days/ 5 BN 2/2-4/11/1958: 69 days/ 6 BN 2/5-4/9/2013: 64 days/ 4 BN 12/23/1962-2/23/1963: 63 days/ 6 BN 11/23/2022-1/23/2023: 62 days/ 3 AN The recent -AO streak apparently ended yesterday at 62 days. What's very notable is how much warmer it has been in the SE US vs during other very long -AO streaks with an anomaly of +3 at RDU vs the other four having had anomalies of a very cold -4 to -6! And on top of that, I'm using updated 30 year normals in the calculations, meaning a warmer normal for the current streak.

12Z Euro is delayed due to maintenance being done:

Note that the GEFS forecast is for a +NAO in early Feb. Since 1950, 6"+ snowstorms at RDU have occurred equally frequently between +NAO (~1/3), neutral NAO (~1/3), and -NAO (~1/3) as I've posted in the past, which admittedly was a surprise to me. So, a +NAO, alone, should not be a reason to feel there's virtually no chance for a big snow there and in the SE in general in early Feb. The hard data says that's not the case. That doesn't at all mean I'm predicting one though.

Indeed, that's what the model consensus has been showing for several days now with the 60N wind dropping from 50 m/s now to ~10 on 1/28-29. (See model consensus forecast image below.) It would need to get to below 0 to be called "major" as I understand it. That's looking very unlikely now since the models have hardly budged. But this still begs this question: With a drop-off of the winds of 80%, would that be close enough to allow for any potential cooling effects on the SE US to possibly be somewhat similar to what a "major" SSW would tend to cause, especially considering that the Arctic warming looks to be very strong? I mean if it doesn't get all the way to 0, why would that totally cancel out the potential effects?

Yesterday's 12Z EPS mean had been the coldest run yet for the SE in the 11-15. Then today's 0Z backed off some. But now the new 12Z is back to at least as cold as yesterday's 12Z, and even slightly colder at times. For example, yesterday I had noted that the 12Z mean had Charlotte at 30 as of 12Z on 2/4, which was 10 colder than just three runs earlier. Then today's 0Z backed off some to 33. The brand new run has 29. This is significant because this is near the period that some GFS runs/GEFS members are sniffing out a somewhat elevated chance for wintry precip. Looking at wintry precip., this new run's mean has a good bit more than yesterday's almost as cold run and this is mainly for inland areas though the NC coast, especially upper, has a bit of a signal.