GaWx

I was also at Peachnet. So, were several others that are regulars here and were also at Eastern. I remember lookout, highway#, and NE GA, among others. Meanwhile, the current storm means business!

We get it. That storm is likely not going to give you what you want. But the winter/early spring in WNC is likely not hanging on it. There’s still a very long way to go, especially with it being a strong Nino.

When there’s a +1.0 or higher ONI peak in fall/winter going back to late 1800s, Raleigh has had only 29% of their snow on average through Jan 20th. More details below: -31 winters since 1888-9 -Nov avg: 0.2” -Dec avg: 0.9” -Jan 1-20 avg: 1.1” -Jan 21-31 avg: 0.9” -Feb avg: 2.4” -Mar avg: 1.7” -Apr avg: 0.4” -So, Nov-Jan 20 avg: 2.2” -So, Jan 21-Apr avg: 5.4” -So, on average only 29% of SN falls at RDU through Jan 20th & 71% Jan 21st+ -Thus, a very long way to go. -Regarding 6”+ storms for these 31 periods at RDU, median date not til Feb 10-11 -There have been more 6”+ events during these 31 there in Mar (4) than either Feb (3) or Jan (3)!

No, it is the opposite. The daily is still high end strong. That’s a good bit stronger than the average for being almost in mid January. My stats don’t even consider whether or not El Niño weakens quickly.

For RDU El Niños that were moderate or stronger: snowfall: -31 winters since 1888-9 -Nov avg SN: 0.2” -Dec avg SN: 0.9” -Jan 1-20 avg SN: 1.1” -Jan 21-31 avg SN: 0.9” -Feb avg SN: 2.4” -Mar avg SN: 1.7” -Apr avg SN: 0.4” -Nov-Jan 20 avg SN: 2.2” -Jan 21-Apr avg SN: 5.4” -So, only 29% of SN through Jan 20th & 71% Jan 21st+ -Thus, a very long way to go. -Regarding 6”+ storms, median date not til Feb 10-11 -More 6”+ events in Mar than Feb or Jan!

I was a bit slow today lol. Though 0Z GFS just missed it with a +4, it actually had a reversal days 15-16 instead. It looks like the 12Z GEPS is probably close to 0. The 0Z was at -1. Going to be interesting next few days following this. Could be implications for Feb, which already tends to have good climo in El Niño. But if reverses, it doesn’t look to be a strong reversal but probably a rather weak one. Regardless, I’d love to see it. Any reversal is significant and would be a surprise vs recent EPS runs.

Check today’s 0Z EPS out for Jan 17th! Are we going to sneak in an unexpected major SSW in 9 days? The mean has sunk to just +1 m/s (only the 12/25 and 12/26 runs lower and those were for early Jan) with probably 1/3 or so of the members below 0: Compare to yesterday, when mean dipped only to +5: For 1/17 on 0Z runs, GEPS and GEOS were at -1 while the GFS and FNMOC were at +4 and GEFS was at +8.

It is still very early. A significant majority of major SE El Niño snowstorms have occurred after mid January. Even in a snowy El Niño winter, often there’s only one widespread major storm in the SE. So, we have plenty of time for that storm to happen.

Fwiw from the average of the last 48 CFS runs, a cool mid-Feb with a good portion of the E US 1-3 BN 2/11-18, which is during peak snow climo:

1. Even though I replied to your post, I didn’t intend for it to be just for you. Temperatures are an important aspect of winter to monitor on their own, especially during winter. Although I’m not yet expecting super cold, the fact that it’s possible in ~10 days is intriguing. Widespread cold on its own can have at least as much (if not more in some cases) impact as a snowstorm. Plus it could set the table for a followup winter storm in more ways than one though that’s beside the point. 2. Last Dec MJO: I’m pointing out similarities for those who may find it interesting. You don’t care, but others might. There are a lot of members and guests that read these. I love to look at both similarities and differences of various factors when looking back in wx history.

Although likely too cold, the even colder 12Z CMC is somewhat similar with very cold air moving into the SE on 1/17, which would likely lead to the coldest of the winter to this point. Similar to last winter’s coldest around Christmas, this appears like it would be during a moderate to strong MC phase of the MJO interestingly enough. The strong -EPO/-AO/-NAO combo doing its thing.

In my area we quite possibly will have the coldest first half of January since 2018 with right at normal.

The 0Z 1/7/24 EPS mean has maintained the Jan 11-18 period of near or sub -150 (-1.5) EPO that was on this 0Z 1/4/24 run. An 8+ day long period of -150 or lower has occurred about once every two winters on average since 1948 with no winter having more than two of them. The 0Z 1/7/24 EPS run is implying that the low of this period would probably be sub -300. https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt

Thank you. So, the 0Z 1/7/24 EPS mean has maintained the Jan 11-18 period of near or sub -150 (-1.5) that was on the 0Z 1/4/24 run. An 8+ day long period of -150 or lower has occurred about once every two winters on average since 1948 with no winter having more than two of them. This EPS run is implying that the low of this period would probably be sub -300. https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt

Does anyone have the latest EPO forecast from the EPS or any model? TIA

Thank you!

I follow you. I just wanted to make sure that y’all were aware of the fresh snowcover bias. Regarding the CMC, it overall has a colder bias than the GFS. I don’t mean just over snowcover. I mean in general. Even if it doesn’t get as cold as the 18Z GFS but it still gets very cold, that would mean quite possibly the second winter in a row with the coldest of the season when the MJO was in a moderate to strong MC phase.

I saw the insane cold on the 18Z GFS. I recommend taking the GFS with a huge grain over fresh snow-cover because it has had a strong cold bias over modeled fresh snow-cover for at least several years: https://dtcenter.org/sites/default/files/events/2020/4-patel-ronak.pdf Cold is coming, no doubt. But the insane cold that far south on the 18Z GFS isn’t realistic. I believe the Euro may also have this bias (at least it did a few years ago), but I don’t think to this degree.

So, the 0Z 1/4 EPS was forecasting a strong -EPO for mid Jan, the period I’m analyzing for SE winter storm chances. That would be a pretty big deal if it verifies. 80% of the moderate right side MJO with widespread SE mod to heavy wintry precip had a strong -EPO. This shows an 8 straight day period of sub -150. How often does that occur in any one winter? There have been 40 instances since 1948 or about one every other winter on average. No winter has had more than two. So, if that EPS is right, it would be a pretty big deal, especially when combined with a -AO. But this is all looking to go against a robust MC MJO. The lengthy strong EPO strings fully in Jan were (temps/wintry precip are for SE): 1/10-18/1957: cold (-PNA, +AO, neut NAO) 1/18-29/1961: very cold/wintry (+PNA, -AO, neut NAO) 1/15-22/1962: cold/wintry (-PNA, +AO, neut NAO) 1/9-31/1963: very cold (+PNA, -AO, -NAO) 1/17-26/1969*: slightly AN (-PNA, -AO, -NAO) 1/1-11/1974: mild (-PNA, +AO, neut NAO) 1/1-9/1979: very cold to cool (MJO mod 7-6) (-PNA, -AO, neut NAO) 1/20-28/1991: cold/wintry (MJO mod 3-4) (neut PNA, +AO, neut NAO) 1/4-14/1993: mild (MJO strong 8-1-2) (-PNA, +AO, +NAO) 1/1-9/2005*: warm (MJO mod 4-5) (-PNA, +AO, +NAO) 1/14-23/2009: very cold (MJO strong to mod 7-8-1)(+PNA, +AO, +NAO) 1/20-28/2014: very cold/wintry (MJO mod 6-7) (+PNA, -AO, +NAO) 1/1-11/2015*: cold (MJO mod to strong 5-6) (neut PNA, +AO, +NAO) 1/1-8/2017: cold/wintry (MJO rt side COD) (-PNA, +AO, neut NAO) * = El Nino Analysis: - 10 of 14 were cold - 5 of 14 were wintry - MJO: all over the map - +PNA: all 4 very cold - All mild to warm had -PNA but half the -PNAs cold - Twice as many -PNA as +PNA - -AO averaged colder (4 of 5 cold) than the more common +AO but 2/3 of +AO still cold - Only 2 of 14 -NAO and one of those mild - 6 of 7 neut NAO and 3 of 5 +NAO cold Conclusions for upcoming -EPO: - Having a -AO will favor cold - Progged to have weaker -PNA than the 8 -PNAs listed. Thus, I don’t think it would prevent cold though it likely would prevent extreme cold. - Better chance for cold without than with widespread significant wintry precip but that’s no surprise since it is the SE. But 5 of 14 (36%) being wintry beats the odds of most 8-12 day periods in Jan. - And cold looking very likely per EPS. All 5 wintry cases were cold. That’s 5 of 11 (45%) cold cases being wintry. That’s high for the SE for an 8-12 day period in Jan! -Weak -PNA would likely neither hurt nor enhance the wintry chance. -If MJO is strong like what GEFS has, that may hurt wintry chance. Hoping MJO more like EPS. -Oddly enough, -AO/-NAO surprisingly didn’t seem to help with wintry when considering these 14 cases fwiw though I’d still rather have them. Anyone have the latest EPS (or any model) EPO forecast?

1. But if ONI peak were to end up +2.00+, why wouldn’t it be known as a low end super? I don’t follow you. 2. Now regarding RONI, which many have been saying is more relevant to sensible wx, it looks to most likely peak in only low end strong.

Today’s OISST dropped to +1.87, lowest since 11/16. But that’s a huge drop of 0.2 in just 2 days. Often there’s a correction soon after a sharp move. Regardless, OISST would likely need to average under +1.80 Jan 7-31 to prevent a super ONI peak. What are the chances for that? I’m still saying pretty low but it obviously is doable.

-That’s not Nov but rather it’s OND, which was +1.94 (rounds to +1.9). -Nov, itself, was actually +2.02. Dec was +2.07: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt -That means that Jan ERSST only needs to end up at +1.91 to allow NDJ to average +2.00. And you don’t need three months of +2.00+. Just the average of the 3. Currently, Jan 1-5 is ~+2.15 for ERSST, based on it having averaged 0.08 warmer than OISST over the last 5 months. For 11/1/23-1/5/24, ERSST is ~+2.05. To bring down ERSST to under +2.00 for 11/1/23-1/31/24, ERSST would need to be +1.87 or cooler for 1/6-31, which equates to ~+1.80 or cooler for OISST for 1/6-31. So, do folks think that OISST will average <+1.80 for 1/6-31? That’s about what it will take to prevent a super ONI peak. OISST hasn’t had a single day under 1.80 since Nov 16. Opinions? Yesterday it was at +1.94 but that was only after a good drop. I think the odds are pretty low, but we’ll see. That’s why I’m favoring that we get a super peak as of now.

Absent a steep fall in 3.4 the rest of the month, there’’d actually be a very good chance for a super as unrounded NDJ ONI (ERSST, which has been running slightly warmer than OISST for several months) would be +2.00+. ND is ~+2.05.

Followup on my search for a big SE winter storm when MJO was strong on the right: Couldn’t find any when right side strong like GEFS has (amp 2+) but found 3 big and 2 moderate storms when MJO was right side moderate (like EPS has): -1/24/1991: mod SN ATL-CLT; mod phase 4 -3/13/1993: historic SN for many; mod phase 4 -12/18/1996: mod SN ATL-GSP; mod phase 5 -1/9-10/2011: big storm for many; mod phase 5-6 -1/17/2018: big storm for many; mod phase 4 So, the progged MJO is a negative factor as most of us already knew. However, if it would end up moderate like the EPS instead of the GEFS’ strong, history says that there’d be a shot at a moderate to big winter storm over a good portion of the SE should the SE get as cold as the EPS shows (5-10 BN averaged over up to 10 days). Note that 3 of the 5 were during 1/9-24, in/near the progged cold period and near coldest climo though none were during El Niño. How was NAO/AO/PNA/EPO during these 5? 1. NAO range was -0.3 to +1.3. 2. AO range was wide: -3.4 to +2.2 (3 +, 2 -) 3. PNA range VERY narrow: -0.2 to -0.4 4. EPO range -320 to +60 with 4 of 5 strong - So, weak -PNA and strong -EPO prevailed. None had a moderate or stronger -NAO. AO all over the place. Has anyone seen an EPO prog?

The 0Z EPS, which is colder than the GEFS, is the coldest run yet overall for midmonth (1/14+) for the C & E US, including 5-10 BN SE. This includes extreme cold anomalies over the C Plains and a very cold Midwest. It implies two Arctic highs coming down into the Plains feeding cold but not plunging into the SE. This of course doesn’t necessarily mean there would be a widespread significant SE winter storm near or just after this cold period (1/14-21+) as widespread big SE winter storms are pretty infrequent. I’m not even saying I’d bet on it. But if there actually would be a 10+ day period averaging 5-10 BN in the SE during mid to late Jan (at/near the coldest climo means of the year) in El Niño, that would imply an above climo chance for SE wintry precip overall, including a significant winter storm chance. What would be best for snow would be for a very cold high to plunge into the Midwest and then move E near the Ohio Valley instead of into TX/OK because it would allow for the chance for moisture to return while it is still cold. Looking at indices, whereas the progged strong right side MJO isn’t at all favorable, the -NAO/-AO keeps the door open. If I get time, I’ll check to see if I can find a big SE winter storm when the MJO was strong on the right. Is the EPS right or is it too cold? I don’t know the answer.