February 2023

[donsutherland1]

The Internet is again abuzz with long-range guidance showing a potential stratospheric warming event. What follows is speculation about a cold and possible snowy March. The usual caveats about model skill at extended ranges and the poorly-understood nature of such events applies.

But if one looks at the excellent FU-Berlin site, one finds something that is not being mentioned. The long-range guidance isn't hinting at just an ordinary SSW event, but suggesting an early final warming event. Although there are erroneous date labels on the chart (showing 2021-2022 in places, the chart is for 2022-2023).

From 1950-2020, there have been 7 early final stratospheric warming events (occurring prior to day 80 in the year): 1954, 1959, 1961, 1964, 1975, 1986, and 2016. The outcomes for March and April are mixed. 1975 had nationwide cold during March. 2016 had nationwide warmth during March. 1954 had near nationwide warmth during April. 1975 had near nationwide cold during April.

For New York City, 5/7 (71%) had much below normal March-April two-month snowfall.

[eduggs]

12z GEFS actually looks pretty good to me for Sat. It's the most threatening run in a while for wintry weather somewhere along the east coast. Red flags for sure, but it's hard to dismiss completely at this non-fantasy range.

[Rtd208]

Honestly I don't think a SSWE is going to benefit us at all snow wise at this point. More then likely it will be all for naught if it even occurs. 

[Wxoutlooksblog]

40 minutes ago, eduggs said:

12z GEFS actually looks pretty good to me for Sat. It's the most threatening run in a while for wintry weather somewhere along the east coast. Red flags for sure, but it's hard to dismiss completely at this non-fantasy range.

I think it would be quite difficult for coastal areas to get accumulating snow out of this no less any snow at all. Temperatures probably in the upper 30s at best.

WX/PT

[Volcanic Winter]

I’m so excited for our 7 months of 80+ degrees after a snowless winter. 

Definitely wasn’t expecting to hate a winter more than 19-20 so quickly. Extremely frustrating. 

I’ll take the SSW if it occurs, because honestly why not? I know some people will be bummed if it cools down early spring, but I assure you, the summer inferno is coming one way or another. You’ll get your incendiary temperatures soon enough. 

[Rtd208]

30 minutes ago, Wxoutlooksblog said:

I think it would be quite difficult for coastal areas to get accumulating snow out of this no less any snow at all. Temperatures probably in the upper 30s at best.

WX/PT

Yeah I think he is grasping at straws. 

[Volcanic Winter]

3 minutes ago, Rtd208 said:

Yeah I think he is grasping at straws. 

I mean from a track standpoint it looks pretty good to me, the problem of course is that everything is torched up through CNE. Seems like it would take some big changes from the OP depiction to have a chance. 

I’ll have my umbrella handy. 

[Rtd208]

1 minute ago, Volcanic Winter said:

I mean from a track standpoint it looks pretty good to me, the problem of course is that everything is torched up through CNE. Seems like it would take some big changes from the OP depiction to have a chance. 

I’ll have my umbrella handy. 

Yeah you need to look at more then just the track (general statement).

[Stormlover74]

2 minutes ago, Volcanic Winter said:

I mean from a track standpoint it looks pretty good to me, the problem of course is that everything is torched up through CNE. Seems like it would take some big changes from the OP depiction to have a chance. 

I’ll have my umbrella handy. 

The euro would be a couple inches north and west

[eduggs]

8 minutes ago, Rtd208 said:

Yeah I think he is grasping at straws. 

We all know it's a low likelihood wintry threat. That's due to the antecedent conditions. But while many on here and other nearby regional forums obsess about low temperatures, tenths of snow accumulation, or long range fantasy pattern changes, I like to focus on mid-range forecasting of wintry events that are actually plausible.

A high amplitude longwave trof favorably aligned with the east coast is a major ingredient in snow threats for our region. Yes the other major ingredient is missing, but we've certainly spent lots more pages discussing threats of less potential significance already this winter.

[winterwx21]

36 minutes ago, Wxoutlooksblog said:

I think it would be quite difficult for coastal areas to get accumulating snow out of this no less any snow at all. Temperatures probably in the upper 30s at best.

WX/PT

Yep. And think about what a thread the needle it would be if next weekend somehow works out. This week is going to a blowtorch, and the following week is going to be a blowtorch. It would take incredibly great luck to get a snow event in between 2 extremely warm weeks, during a minor very brief cooldown. Our very brief cooldown next weekend will have high temps in the 40s, not impressive at all. It would take a storm taking a perfect track and a strong enough storm to pull in cold air to get accumulating snow near the coast. Extremely unlikely. 

[winterwx21]

50 degrees here. What a recovery, from a high temp of 26 yesterday to 50 today. 

[MANDA]

6 minutes ago, winterwx21 said:

50 degrees here. What a recovery, from a high temp of 26 yesterday to 50 today. 

Quite the recovery indeed.

[Volcanic Winter]

[eduggs]

GEPS also noticeably improved over 0z. The longer each cycles avoids trending in the wrong direction, the more I'm compelled to get drawn in a little bit.

[mattinpa]

17 minutes ago, eduggs said:

GEPS also noticeably improved over 0z. The longer each cycles avoids trending in the wrong direction, the more I'm compelled to get drawn in a little bit.

Any chance we get colder than the 40s that are predicted? The projected temps would give a cold rain. But yes might as well watch it. It would be gone quickly also, but any event this winter is a big thing. 

[Wxoutlooksblog]

50 minutes ago, winterwx21 said:

Yep. And think about what a thread the needle it would be if next weekend somehow works out. This week is going to a blowtorch, and the following week is going to be a blowtorch. It would take incredibly great luck to get a snow event in between 2 extremely warm weeks, during a minor very brief cooldown. Our very brief cooldown next weekend will have high temps in the 40s, not impressive at all. It would take a storm taking a perfect track and a strong enough storm to pull in cold air to get accumulating snow near the coast. Extremely unlikely. 

I don't hold the blowtorch of this week against the event next Saturday. We've had a number of snowstorms which followed warm-ups even to 60 or 70 degrees (in late Feb or March). The problem is the likelihood of a relatively poorly organized storm system and lack of really cold air available at the time of the event.

WX/PT

[GaWx]

11 hours ago, donsutherland1 said:

The Internet is again abuzz with long-range guidance showing a potential stratospheric warming event. What follows is speculation about a cold and possible snowy March. The usual caveats about model skill at extended ranges and the poorly-understood nature of such events applies.

But if one looks at the excellent FU-Berlin site, one finds something that is not being mentioned. The long-range guidance isn't hinting at just an ordinary SSW event, but suggesting an early final warming event. Although there are erroneous date labels on the chart (showing 2021-2022 in places, the chart is for 2022-2023).

From 1950-2020, there have been 7 early final stratospheric warming events (occurring prior to day 80 in the year): 1954, 1959, 1961, 1964, 1975, 1986, and 2016. The outcomes for March and April are mixed. 1975 had nationwide cold during March. 2016 had nationwide warmth during March. 1954 had near nationwide warmth during April. 1975 had near nationwide cold during April.

For New York City, 5/7 (71%) had much below normal March-April two-month snowfall.

Don and others,

 What may very well turn out to be different from the years listed is that the upcoming strat warming, whether final or not, is looking increasingly likely to be "major" (see 1st image, in which the GFS is showing quite the major event with 60N 10 mb winds dropping to well below 0 m/s). Before anyone says anything about the unreliability of the GFS vs ensemble means, it has been leading the way, which is quite evident when looking back to 1/31 runs at the Stratobserve website at https://stratobserve.com/ens_ts_diags

 

  Another thing to keep in mind is the Scandinavian-Greenland (S-G) dipole, which looks to me like it is forecasted to exceed 40 mb per the 2nd image below. 

 

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JD030940

"The correlation field indicates that ensemble members with lower MSLP over eastern Greenland and higher MSLP over Scandinavia forecast weaker U1060."

 "Of the 23 SSWs (Karpechko et al., 2017), we find eight (35%) followed a similar evolution to 2018 and were preceded by an S-G dipole exceeding 40 hPa within 15 days of the start date of the SSW. Given the total of 345 days preceding the 23 events (and assuming independence), this is 2.3 times larger than the climatological likelihood (since 40 hPa is approximately the 99th percentile, it would be expected that it was exceeded on 3-4 days)."

 "We therefore suggest the S-G dipole should be monitored operationally as a precursor to SPV weakening."

"When 2018 is included, 78% of the major SSWs preceded by an amplified S-G dipole were downward propagating (Karpechko et al., 2017), with only March 1981 and February 2008 otherwise. This is larger than the observed ratio of 57% (although the sample is too small to draw robust conclusions) but is in agreement with Birner and Albers (2017), who note larger tropospheric impacts following SSWs preceded by enhanced tropospheric wave activity."

 Per table 1 from this article, the following 8 SSWs had a 40+ mb S-G dipole peak during the 15 days prior:

Feb of 1979, Feb of 1980, March of 1981, Feb of 1984, Jan of 1985, Jan of 1987, Jan of 2006, and Feb of 2008.

 Also, Feb of 2018, which this article highlighted, had a 40+.

 So, one might want to focus on the tropospheric impacts of the above listed 9 SSWs to get a better idea of how the upcoming SSW may affect the E US late this month into March+. I say late this month because I believe based on the timing of past cases that any potential cold resulting from this may start as early as the last week of this month.

 

Image 1 showing that today's 0Z GFS is forecasting a major SSW:

 

Image 2 suggesting likelihood of S-G dipole peak of 40+ mb coming tomorrow:

[CPcantmeasuresnow]

3 minutes ago, GaWx said:

Don and others,

 What may very well turn out to be different from the years listed is that the upcoming strat warming, whether final or not, is looking increasingly likely to be "major" (see 1st image, in which the GFS is showing quite the major event with 60N 10 mb winds dropping to well below 0 m/s). Before anyone says anything about the unreliability of the GFS vs ensemble means, it has been leading the way, which is quite evident when looking back to 1/31 runs at the Stratobserve website at https://stratobserve.com/ens_ts_diags

 

  Another thing to keep in mind is the Scandinavian-Greenland (S-G) dipole, which looks to me like it is forecasted to exceed 40 mb per the 2nd image below. 

 

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JD030940

"The correlation field indicates that ensemble members with lower MSLP over eastern Greenland and higher MSLP over Scandinavia forecast weaker U1060."

 "Of the 23 SSWs (Karpechko et al., 2017), we find eight (35%) followed a similar evolution to 2018 and were preceded by an S-G dipole exceeding 40 hPa within 15 days of the start date of the SSW. Given the total of 345 days preceding the 23 events (and assuming independence), this is 2.3 times larger than the climatological likelihood (since 40 hPa is approximately the 99th percentile, it would be expected that it was exceeded on 3-4 days)."

 "We therefore suggest the S-G dipole should be monitored operationally as a precursor to SPV weakening."

"When 2018 is included, 78% of the major SSWs preceded by an amplified S-G dipole were downward propagating (Karpechko et al., 2017), with only March 1981 and February 2008 otherwise. This is larger than the observed ratio of 57% (although the sample is too small to draw robust conclusions) but is in agreement with Birner and Albers (2017), who note larger tropospheric impacts following SSWs preceded by enhanced tropospheric wave activity."

 Per table 1 from this article, the following 8 major SSWs had a 40+ mb S-G dipole peak during the 15 days prior:

Feb of 1979, Feb of 1980, March of 1981, Feb of 1984, Jan of 1985, Jan of 1987, Jan of 2006, and Feb of 2008.

 Also, Feb of 2018, which this article highlighted, had a 40+.

 So, one might want to focus on the tropospheric impacts of the above listed 9 major SSWs to get a better idea of how the upcoming SSW may affect the E US late this month into March+. I say late this month because I believe based on past cases that any potential cold resulting from this may start that early.

 

Image 1 showing that today's 0Z GFS is forecasting a major SSW:

 

Image 2 suggesting S-G dipole peak of 40+ mb coming tomorrow:

Yes what he said. 

The 35% that I understand sounds promising. 

[wdrag]

SFW:  Looks complicated and determining whether warming actually occurs first at 1 hPa or 10 hPa.  I'm not dependent on SFW-SSW for weather but respect it's place in research and attempted outlooking.  

I guess, I interpret the early SFW meaning a possible -NAO in spring?  But then is the -NAO in spring as favorable for blocking and snow here?  Don stats say no but sample size looks tiny.

I'll look at 2/11 for now and note the GEPS is finally on board with the EPS at 500MB and all have a little qpf here in a colder scenario. GEFS might be too fast to the east but was first cueing us to the potential. 

Also fwiw...the immediate coast seems to be missing what will soon be a very large ocean storm grazing Cape Cod (late Monday the 6th) and modeling is basically agreeing on closing off a low aloft just to the s-se of CC

 

[wdrag]

So I read conflicting info... is it SSW we're paying attention to? or an SFW?  It seemed to me that big NH SSW's occur JAN-early Feb and that SFW's are the feature Mar-May?  

[eduggs]

49 minutes ago, mattinpa said:

Any chance we get colder than the 40s that are predicted? The projected temps would give a cold rain. But yes might as well watch it. It would be gone quickly also, but any event this winter is a big thing. 

I don't have any special prognostication abilities. The temperature is partly precipitation dependent. I think low 40s is a reasonable high temp forecast for Sat at this juncture. If it's dry on Sat with the frontal passage scenario shown on the GFS, we should hit 40 (e.g., with ~28 dpt) before cooling off after dark. But if there's precipitation like the EC or ICON show, it would likely be more like upper 30s dropping through the mid and maybe low 30s.

[LongBeachSurfFreak]

I’m going to say this now, the futility record goes down in flames in March. As much as I would like to forget this non winter and move on to spring there are storms on the way and one if not more will produce 

[mattinpa]

2 minutes ago, eduggs said:

I don't have any special prognostication abilities. The temperature is partly precipitation dependent. I think low 40s is a reasonable high temp forecast for Sat at this juncture. If it's dry on Sat with the frontal passage scenario shown on the GFS, we should hit 40 (e.g., with ~28 dpt) before cooling off after dark. But if there's precipitation like the EC or ICON show, it would likely be more like upper 30s dropping through the mid and maybe low 30s.

Thanks. Explains things well for why there could be some (if not a lot of) chance for a snow event. 

[GaWx]

1 hour ago, wdrag said:

So I read conflicting info... is it SSW we're paying attention to? or an SFW?  It seemed to me that big NH SSW's occur JAN-early Feb and that SFW's are the feature Mar-May?  

Walt,

1. The GFS is explicitly calling for a major SSW in mid-Feb per the first image I posted. I can't speak for others, but that's what I'm paying attention to. It is highly doubtful imho that it could also end up as an SFW because none have occurred as early as Feb.

2. Major SSWs have occurred as late as March 23rd per this:

https://en.m.wikipedia.org/wiki/Sudden_stratospheric_warming#Classification_and_description

 

 Also, regarding the 9 major SSWs that occurred within 15 days of a 40+ mb S-G dipole event, the following 5 of the 9 were near or later than the upcoming event, which looks to occur ~2/15:

2/22/1979, 2/29/1980, 3/4/1981, 2/24/1984, and 2/12/2018

 

[SnoSki14]

31 minutes ago, LongBeachSurfFreak said:

I’m going to say this now, the futility record goes down in flames in March. As much as I would like to forget this non winter and move on to spring there are storms on the way and one if not more will produce 

I hope we set the futility record. All this garbage should have something to show for it. 

I don't need a pity March advisory event that's gone the next day. 

[donsutherland1]

44 minutes ago, wdrag said:

So I read conflicting info... is it SSW we're paying attention to? or an SFW?  It seemed to me that big NH SSW's occur JAN-early Feb and that SFW's are the feature Mar-May?  

Final warnings usually occur March-May. The earliest was in 2016 (near the start of March). It’s too soon to be sure what lies ahead.

[donsutherland1]

The short-lived Arctic blast is now a rapidly fading memory. Temperatures surged into the upper 40s and even lower 50s this afternoon. At Boston, the temperature soared to 51° following yesterday's -10° reading. That is the third 50° or warmer day following a -10° or below temperature. Those days are:

December 21, 1875: 55° (December 20, 1875: -11°)
December 21, 1875: 54° (December 20, 1884: -10°)
February 5, 2023: 51° (February 4, 2023: -10°)

Generally above normal and much above normal temperatures will continue into at least early next week. During the February 10-11 period, there is a chance that a storm could bring some frozen precipitation to interior areas.

The potential exists for temperatures to run generally above to much above normal through mid-month. Both the CFSv2 and EPS weeklies show much above normal temperatures through the second week of February. Afterward, there is disagreement among the ensembles about whether it turns colder for a sustained period or just briefly.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.6°C for the week centered around January 25. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.32°C and the ENSO Region 3.4 anomaly has averaged -0.70°C. La Niña conditions are beginning to fade and they should evolve to neutral conditions during late winter or early spring.

The SOI was +16.57 today.

The preliminary Arctic Oscillation (AO) was +0.087 today.

On February 3 the MJO was in Phase 3 at an amplitude of 1.556 (RMM). The February 2-adjusted amplitude was 1.645 (RMM).

 

[eduggs]

18z ICON and GFS once again slightly improved compared to 12z. 18z GEFS with another notable improvement as well, with the mean precipitation chart finally indicating a coastal SLP on Saturday with some cold-side precipitation.

[Brasiluvsnow]

3 hours ago, LongBeachSurfFreak said:

I’m going to say this now, the futility record goes down in flames in March. As much as I would like to forget this non winter and move on to spring there are storms on the way and one if not more will produce 

your keyboard to Mother Natures ears,,,the only thing is ( for snow lovers  ) March snow is gone a day later but after enduring this winter I will gladly take any snowstorm even a March snowstorm