Analogs:
Top ENSO analogs: 1957/1965/1991*
MEI Analogs: 1986/2009
Top Pacific Analogs: 1965/1972/1995
Polar Analogs: 1957/1965/1987/2009
EMI/Orientation Analogs: 1982/1991*/2015
1957/1965/1972/1987/2009 are my highest weighted analogs
The ENSO will likely end up as a basin-wide(with more of a western lean like 1957/65 as Nino 4 warms and Nino 1+2 cools), with periods of Modoki forcing. I do not think that this is a wall to wall cold and snowy winter, but rather bouts of favorable patterns/timeframes, with most of the bulk being in the second half of the winter(Feb). I think we overall end up N-slightly AN for the winter, with Feb being BN, and Dec slightly AN, with Jan being around N. There’s too much variability and unpredictability to pinpoint specific temp anomalies for those specific months, but I still think we overall end up N-slightly AN.
Snowfall:
The range this winter is extremely large, with the maximum high-end potential being a top 5 winter or another horrible, low-snow winter. Strong+ ninos tend to be very boom or bust winters. With the exception of 1994/95, every analog year I had was either under 10” or over 30”. As I mentioned before, the main thing that will determine the fate of this winter is the polar domain. With the -QBO/++AMO, as well as bouts of favorable forcing setting up at times, the polar domain is looking good for this winter. While we have a -PDO, the strong El Nino will win out and override the state. The warmest anomalies being over and east of the dateline is a very good thing and very different to the forcing we’ve been seeing over the past few years. The active STJ should provide us with plenty of storm opportunities and ample moisture, snow or rain regardless. Thus, this is also the best chance since 2016 for a HECS/KU. Even if we don’t get a KU, the active STJ provides many opportunities for multiple SECS/MECS.
That is why I went well AN for snowfall for this year. I doubt we see a near-normal year; either much BN or much AN. There is a lot of potential this year, and as of now, things seem to be looking good. The warm Atlantic will also provide extra moisture for storms. Going around the mid-range this year for snowfall doesn’t appear to be a good idea. This year definitely won’t be that cold overall, but we don’t need extreme back-to-back cold anomalies to get snowfall. All we need is one wave to time up right. With a Nino, the Pacific shouldn’t be too much of a problem this year. ENSO influences PDO, not the other way around; especially at this strength.
I also went for a more N/S gradient in my map than a W/E gradient. The big nino years here had a more north-south orientation for the gradient than a west-east(obviously being more west still favors more). Although we’ll see some CAD storms, especially earlier in the season, I don’t think we’re going to be seeing too many of them overall. I think the PNA this year will average out to be neutral-slightly positive, with the western ridge flexing at times, increasing in frequency as the winter progresses. This should favor more Miller A/C type storms, which generally aren’t as W/E gradient oriented.
Given how things appear to be progressing, and the best-looking year in several years, I believe that going bullish on a high snowfall winter is the right decision to make.
Summary:
Overall, I am sold for a well AN snowfall winter for the Mid-Atlantic and SE, and BN for NE. The strong Nino and STJ should heavily favor the MA/SE, and lead to suppression issues not much further north. ++AMO favors further S blocking, which in turn favors a further southern displaced track. Along with the STJ and other factors, the main focus of this winter on the EC will likely be the MA.
December, although not favored by Nino climatology, doesn’t look that bad anymore, and might be AN in snowfall, with a -NAO setting up for the early part of the month, and forcing returning to favorable phases by mid-late month. Although I expect it to still end up slightly AN, there’s definitely the possibility of the month ending up near normal. We should have a generally transient warmup in mid-Dec before returning to a favorable period later in the month. Although climo before mid-Dec is at best dubious, it is certainly possible to get some events, especially with the pattern setting up. For the month, I could see us getting a few minor events, and maybe even a moderate event. The very end of the month seems to be the best time period for something. I do not expect the PNA to be overall positive, but we could get a few transient +PNA flexes, along with HL blocking around this time. HL blocking setting up in December; and an -NAO is a very good sign for the winter and for higher-magnitude blocks to set up later in the winter.
January looks to be alright, with the favorable forcing from late Dec continuing into the early part of the month. As stated previously, this month will generally be transitional, but the pattern at the start of the month will remain favorable. Thus, after early Jan, it appears to be quiet for a bit, until the end of Jan, where the pattern will become favorable again and continue into Feb. This is also when peak climo starts. Again we might see some +PNA flexes, but it should remain generally variable throughout the month. We should end up around N for this month temp-wise, and snowfall.
February will easily be the best part of this winter, with everything lining up: frequent +PNA flexes, favorable forcing setting up, HL blocking, active STJ, and overall peak climo should make Feb exciting. This isn’t too much of a surprise though, as Nino climatology heavily is backloaded and protrudes Feb as the coldest, snowiest month. We should definitely end up BN for this month in temps and AN in snowfall.
As for indices:
PDO: slightly BN; -0.4 to -0.9
AO: slightly BN; -0.2 to -0.5
PNA: N-slightly AN; -0.1 to +0.3
NAO: N; -0.2 to +0.2
ENSO peak: 1.7-2.0(under super)
ENSO Orientation: West-Tilted Basin-Wide
overall, should be a fun winter to track w/ the first real nino since 2015
.png)
No comments:
Post a Comment