Mid to Long Range Discussion ~ 2023

[wncsnow]

Unfortunately it looks more like more rain then cold front then cold and dry a few days then warm up. 

 

[GaWx]

2 hours ago, wncsnow said:

Unfortunately it looks more like more rain then cold front then cold and dry a few days then warm up. 

 

 It could very well be a mainly dry, cold weekend after next for most of the SE as is quite common with Arctic highs that plunge assuming the plunge occurs. However, NW flow would be favorable for another good upslope mountain event (even if not as good as the great one that just occurred) as the Arctic air comes in and this is on the models. Also, we're still 9-10 days out and there's still plenty of time for change as that's a semi-eternity in model accuracy time as you know. For a not as dry outcome, it would probably be better if the Arctic high moved through the Ohio Valley instead of a deep plunge.

[franklin NCwx]

42 minutes ago, GaWx said:

 It could very well be a mainly dry, cold weekend after next for most of the SE as is quite common with Arctic highs that plunge assuming the plunge occurs. However, NW flow would be favorable for another good upslope mountain event (even if not as good as the great one that just occurred) as the Arctic air comes in and this is on the models. Also, we're still 9-10 days out and there's still plenty of time for change as that's a semi-eternity in model accuracy time as you know.

Some of us only hope for dry. 

[GaWx]

5 hours ago, CaryWx said:

What about the coming SSWE?

 The model consensus continues (as they have for many days now) to insist that a very strong 10 mb Arctic warming is on the way starting early next week. This will mean going from much below normal 10 mb Arctic temperatures/very strong SPV of recent days to way warmer than normal/southward displaced SPV afterward. The 12Z GEFS and other runs have been showing a 40C/72F warming at the North Pole during a mere 120 hours (0Z 1/23 to 0Z 1/28)! Some GFS runs have had 5 day warming there up to 50C/90F! In addition, GFS suite consensus suggests a peak in very early Feb that I think would be AN even for summer!

 What does this mean? A strong SSW late this month is pretty much a certainty. What's unknown is whether it will be called a "major" strong SSW or a "minor" strong SSW. The very impressive degree and speed of warming are there. But to be considered "major", the 10 mb winds at 60N+ have to reverse from W to E. That part is uncertain but GEFS continues to go in that direction. The 12Z GFS may actually have it. Regardless, with this strong of a SSW and it close to "major", it may not matter much.

 As far as the timing of effects on the SE based on past events, it appears that a multi week long cold dominated period could start as early as ~~Feb 10th and possibly last into March. Nobody knows as details are highly speculative. The potential cold shot for late next week is independent of this (SE cold doesn't normally occur at the same time as the SSW) as a mild period will most likely follow that.

[Coach McGuirk]

3 hours ago, wncsnow said:

Unfortunately it looks more like more rain then cold front then cold and dry a few days then warm up. 

 

Could certainly be.  Op GFS is Groundhog's Day.  Rinse. Wash. Repeat.

[GaWx]

 Since 1958 as mentioned before, there have been 13 winters with a major SSW in the late Jan to early Feb timeframe (5 during La Niña):

1958, 1960, 1963, 1971, 1973, 1981, 1987, 2001, 2003, 2006, 2009, 2010, 2018

 They tended to be cold in the SE during multi week long periods within the Feb-March period. I checked the average of three of the indices in Feb/March to see if there was a notable difference between years with and without a late Jan to early Feb major SSW:

1. AO

- With SSW: -1.0; 7 were sub -0.9; only 2 of 13 were positive with highest +0.7

- Without SSW: -0.1

 

2. NAO

- With SSW: -0.4

- Without SSW: +0.2

 

3. PNA

- With SSW: +0.2

-Without SSW: 0.0

 

Conclusions: Years with a late Jan or early Feb major SSW tended to have a -AO/-NAO when averaged through Feb/Mar whereas other years averaged neutral. The PNA averaged neutral for both with and without one. Thus, it appears that the -AO/-NAO combo tendency is a major driving force in tending to make a good portion of Feb/Mar chilly in the SE soon after a major SSW. So, as we go toward Feb 10th or so and beyond, I'll be looking at the AO/NAO forecasts with extra interest.

[GaWx]

 Followup on the 5 La Niña winters with a major SSW within late Jan to early Feb

 As mentioned, all 5 had multi week cold dominated periods in the SE 10+ days later within Feb/Mar due largely to a -AO/-NAO:

 

1971 (cold first half of Feb), 2001 (cold March), 2006 (cold Feb), 2009 (cold 2nd half of Feb to early March), and 2018 (cold March)

 AO on day of and immediately following the major SSW was neutral to positive before turning predominantly negative:

1) 1/18/1971: day of SSW +0.3; + to neutral for 10 days (peak of +1.5); then - on 34 of next 41 days with low of -2.8

2) 2/11/2001: day of SSW +1.5; + for 10 days (peak of +2.9!); then - on 29 of next 35 days with low of -4.9!

3) 1/21/2006: day of SSW -0.2; neutral for 3 days (peak of +0.5); then - on 13 of next 15 days with low of -2.7

4) 1/24/2009: day of SSW +1.1; + to neutral for 7 days (peak +1.9); then - on 14 of next 16 days with low of -3.2

5) 2/12/2018: day of SSW +1.7; + to neutral 12 of next 13 days (peak of +1.9); then - on next 22 days with low of -4.4!

-----------------------------

 Based on the above, I'm educatedly guessing the following after the SSW:

- 1-2 weeks dominated by neutral to +AO with a good chance for it peaking at +1+. The La Niña favored SE ridge would likely be in control. I expect some cries of "winter cancel" over the next 1-2 weeks as this likely mild early Feb period gets closer. Don't let this initial 1-2 week mild dominated period in early Feb fool you into thinking winter is over!

- 3-6 weeks dominated by -AO starting by mid Feb with lowest dipping to -2.5 or lower 

- In the SE, mild dominating early Feb. Cold domination starts ~mid-Feb and continues through the last half of Feb and probably into at least early March. Could extend through mid March.

[wncsnow]

January is toast at this point. Odds of a shutout are growing 

[StantonParkHoya]

Who wants cold in March?

[PackGrad05]

I've said it before, but I think we will end up with an event that pops up within the 5-7 day range suddenly and is marginal (as always) but is a surprise.  It'll probably be sandwiched between two warm-ups.  That's typically the NC way in these types of patterns.

[GaWx]

"@We've not had a day with above normal (cold) national gas-weighted HDDs since Dec 27. The ensuing Dec 28-Jan 17 period yields the fewest GWHDDs on record since 1950 for the period (467.6 vs 30-year normal 630.0)."

 From Weatherdesk's Twitter 

--------------
 So, this is pretty much saying that the E US, where HDD weighting is highest based on population/energy usage, has overall been about as warm as any Dec 28-Jan 17 since 1950 when averaged out over that 3 week period. Other than the several day long mid Jan cold snap largely associated with that very strong upper low, most days have been mild in the SE.

 In stark contrast and to the relief of cold lovers, the next 10 days or so look to average pretty close to normal overall in the SE with a mix of BN and AN...typical midwinter stuff. After this, indications/model consensus favor mild to return to the SE for early Feb. This is actually typical for the period near and immediately following a strong SSW.

 Subsequently, we'll see if the SSW helps to sharply reverse that warmth as we go further into Feb. I think it will based on prior cases of La Niña winters with major SSWs around this time of year and shortly after per the hard data in my prior post as the impending strong SSW/much warmer Arctic strat persists on the models. In my mind, it will likely be a totally new ballgame as much better players (from a cold lover's standpoint) take the field.

 Edit: I forgot to add that other than the GEFS, no model is forecasting the MJO to get into the warm phases outside of the COD. The bc extended Euro, in contrast, has a very inviting track back to inside the COD that then gets to the left side in mid Feb while still inside. That's pretty significant.

[BooneWX]

Thank goodness! Saw 2 days of dry weather on the forecast and started to get concerned it was going to become a trend. 

 

 

 

[KChuck]

2 hours ago, BooneWX said:

Thank goodness! Saw 2 days of dry weather on the forecast and started to get concerned it was going to become a trend. 

That's like the old Bill Cosby joke about the people in Seattle back in the day joking about how often it rained there. When asked if they liked sunny days they said "NO!".  When asked why they answered "Because they dry up the sinuses."

 

 

 

[GaWx]

 The following maps from Weather Desk (**Due to member limitations on attachments, on 2/10/23 I deleted the attached image that was here so I'd have room to repost it in a 2/10/23 post about the mid-Feb 2023 major SSW**) show how often the first 15 days after a SSW in the SE have been mild and how often the subsequent 15 days have been cold. (2009 is actually much colder than its 2nd map when you start the 15 day period 11 days later. 2010 was also cold immediately due to other factors/near record blocking the entire winter in that moderate El Niño). In other words, should warmth dominate in early Feb as models are suggesting, that would actually be an encouraging sign that things are going according to plan of the typical SSW pattern in the SE of warmth followed by lengthy cold. So, while seeing that warmth on the models would be (is already) leading to "winter cancel" proclamations among some, it would actually tell me the opposite. I'd then be looking with even more confidence for a new cold pattern to start around mid Feb and dominate for several weeks:

* 2/10/23 edit: As stated above, I deleted the attachment to make room in my account to allow me to repost it later in this thread.

[CentralNC]

I don't need to remind most of you that 92-93 was a snoozefest until 3/12/1993.  Things can change in a hurry.  Not to that level mind you but I am not giving up yet.

[Grayman]

48 minutes ago, CentralNC said:

I don't need to remind most of you that 92-93 was a snoozefest until 3/12/1993.  Things can change in a hurry.  Not to that level mind you but I am not giving up yet.

Your west of Winston so I don’t blame you but I have little hope in south central NC. I’m marginal even with the best setup. I actually cliff dove in Late December.  Best to dive then of you just surprised your not stuck like a roasted weenie.  Im still a weenie just a realistic one.  

[StantonParkHoya]

38 days until met spring 

[franklin NCwx]

2 hours ago, StantonParkHoya said:

38 days until met spring 

38 days until cold weather sets in

[Met1985]

Just now, franklin NCwx said:

38 days until cold weather sets in

Yeah we've seen this song and dance a lot. 

[Grayman]

Oh my 12z GFS. Here come the weenies in 3,2,1 

[yotaman]

19 minutes ago, Grayman said:

Oh my 12z GFS. Here come the weenies in 3,2,1 

Yep, a dream run for most of NC and SC. Thus, it won't happen.

[Upstate Tiger]

17 minutes ago, Grayman said:

Oh my 12z GFS. Here come the weenies in 3,2,1 

Yeah, 4 winter events for my area over 1 week like 2014.  LOL.  Would take it and call it a winter.   At least we’re seeing fantasy storms now. 

[NC_hailstorm]

Hmm,I see the GFS went all 1899 on us today.Might wanna save that one.

[LakeNormanStormin]

24 inches IMBY on the 12z GFS

Framing it and putting it in my study

[cbmclean]

We gotta stop letting it get our hopes up like this.

[strongwxnc]

Two rounds delivered on the 12gfs. It will change but hello!!



.

[Grayman]

1 hour ago, cbmclean said:

We gotta stop letting it get our hopes up like this.

Yes. No support from ensembles so it’s likely another goofy Gfs run. This weenie will watch the 18z come in though lol 

[wncsnow]

The Euro looks more like winter cancel (more like d.o.a.) 

[TARHEELPROGRAMMER88]

19 minutes ago, wncsnow said:

The Euro looks more like winter cancel (more like d.o.a.) 

Guess who will be right here. For 4 years, you can guess winter cancel will be right and almost always come out on top. 

[GaWx]

5 hours ago, NC_hailstorm said:

Hmm,I see the GFS went all 1899 on us today.Might wanna save that one.

Yeah, like 1899 that 12Z GFS fantasy winter storm was all the way down to (and past) Phil @pcbjr in Hogtown/Gainesville with ~1/4" of ZR. Unlike 1899, this fantasy is from a series of lows and a large portion of the heaviest SE US qpf is actually ZR with some sleet. The precip in N FL, and SE GA/SC/NC is nearly 100% ZR/IP with the 850 mb 0C line to the NW. It would be a massive/historic icestorm for much of that area but fortunately it isn't real. The odds actually favor near or above normal temperatures around that time based on ensembles and the typical timing of SSW effects on the SE.