January 2022 Obs/Disco

[CoastalWx]

3 minutes ago, Sey-Mour Snow said:

Lol that’s what I’ve been saying… pray the GEFS is right .. west coast ridge is trending better though on eps so that’s good, let’s just clean up Alaska. 

GEFS are a pants tent. Just looked lol.

[Allsnow]

7 minutes ago, Sey-Mour Snow said:

Lol that’s what I’ve been saying… pray the GEFS is right .. west coast ridge is trending better though on eps so that’s good, let’s just clean up Alaska. 

Yeah, can’t have that deep trough in Ak. Need to work on that 

[40/70 Benchmark]

7 minutes ago, 40/70 Benchmark said:

DEC

30

 

 

December Forecast Features Mixed Results But Largely Unsuccessful

Pacific Overruled the Arctic

While the overall tone of the 2021-2022 Eastern Mass Weather Outlook included a cold phase oriented Pacific, as evidenced by the primary extra tropical Pacific analogs of 2010-2011, 1970-1971, 1974-1975, 1955-1956, 1954-1955, 1964-1965, 2020-2021, 1988-1989, 2011-2012, 1998-1999, 1999-2000, 2007-2008, 2008-2009, 1975-1976, there was support amongst the analogs for a more variable PNA pattern during the early portion of the winter season. Thus the December portion of the forecast called for some variability within the PNA domain, which in conjunction with the forecast high latitude blocking would have ultimately led to an active month of winter weather culminating the week of Christmas. However, while the high latitude blocking did in fact verify, the Pacific volatility did not.

Here is the original narrative and forecast composite for the period:

December Analogs: 2007, 2000 (x2), 1974, 1970, 1995, 2005 (x2), 2017 (x2), 2008, 1983, 2020

"The polar vortex should take some assaults throughout the latter portion of November and much of December, however, it should remain intact and ultimately intensify and consolidate beyond the new year. This is consistent with basin-wide, mixed-type la nina events. While there may be a mild spell early in the month, it should ultimately turn active with a multitude of moderate snowfalls for the northeast, with the most significant event likely to occur the week of Christmas between the 19th and 26th. A white Christmas is highly likely for the majority of the region and a storm on the holiday itself is a distinct plausibility. Plan accordingly. Although the focus will be on the northeast via a mix of Miller B systems and southwest flow events whenever blocking relaxes, the mid atlantic should receive some snowfall due to a subtle subtropical influx coupled with a variable PNA.

The month should not be exceedingly frigid, as the very mild fall has ensured a late developing cold reservoir. Anywhere from near normal close to the coast to as much -2 departures well inland should cover the monthly departures".

Although the most prolific winter storm during the month in the northeast did in fact occur near the onset of the identified December 19 through December 26 period, it primarily impacted the northern half of the region, and was mainly rainfall for southern New England. More importantly, this particular event was the only noteworthy winter storm of note for the month in large part due to the development of the poorly forecast record RNA pattern. While the forecast episode of high latitude blocking in the NAO domain did in fact materialize as forecast by the holiday period, its development was concurrent with the formation of the strong ridge of high pressure to the south in response to the historically low heights along the west coast in conjunction with the extreme RNA pattern.

 

 This acted to create a very compressed flow between the southern ridge, and high latitude ridge in the vicinity of Greenland, which sheared off storm activity approaching from the active Pacific pattern.

 

 

Note in the annotation above that the two respective ridges of high pressure were situated at just the right distance from once another, at the appropriate latitude to attenuate the storm systems on approach to the Great Lakes. Although this evolution is similar to the year 1970 from the list of analog composite, which featured near record snows for the  month of December, in this instance the heights out west were just so low that heights to the east were elevated enough to be create said compression. Storm systems ejecting out of the PNW were sheared by the compressed flow as they neared the great lakes, so that what we were left with at the longitude of New England was a multitude of minor disturbances, instead of any larger, more discrete, congealed or phased system. This pattern acted to negate what was envisioned last fall as being a very active period with a multiple moderate snowfall events from the period leading up to the holidays and beyond. In turn, the higher heights downstream from the deep trough in the west shifted the core of the warm anomalies from the forecast position in the southwest, into the Texarkana region. It also caused temperatures in the east to be slightly warmer than anticipated.

 

Forecast:

 

 

Actual:

 

 

 

In summary, the most important aspect of monthly forecasting is correctly identifying periods of volatility from the seasonal base state. While this does not show up in the overall DM seasonal composite, it is key to correctly diagnosing the sequential evolution of a season  And while the Pacific pattern throughout the month of December was essentially a more amplified version the overall DM forecast base state of the Pacific, it certainly was not the forecast period of variability and perhaps slight variation that was forecast. This essentially rendered the well forecast high latitude blocking a moot point, and the forecast sensible appeal did not materialize. The discrepancy between how the month of December actually evolved and how it was forecast to evolve has some implications to the outlook for the month of January moving forward.

 

January 2022 Preview

 

Here is the forecast from early last November:

 

January Analogs: 1955, 1956, 1971, 1996, 2006 (x3), 2001, 2018, 2012, 1989, 1965, 1976

"There is a slight chance of a KU magnitude, Archambault type east coast snowfall between approximately December 28th and January 11th, as any residual high latitude blocking erodes and heights lower in the vicinity of Alaska and western Canada. Heights will also lower in the western US as the aleutian ridge retrogrades into the pacific and a sustained RNA accompanies the development of an active, zonal pacific storm track. The core of the warmth should center in the northern plains as the pacific jet eradicates the supply of cold from much of the continent, however, the degree of warmth in the northeast should not be prohibitive of some wintery weather during this peak climo period. Although mixed precipitation and southwest flow events should be the rule, and major pure snow events will be difficult to achieve outside of the higher terrain of upstate New York and central/northern New England. The forecast is for monthly departures to range anywhere from +1 to +3 degrees, but the ceiling is quite high and the potential is there for several degree positive departures. This has the potential to bean exceptionally mild month akin to February 2018.

It is as we begin to flip the calendar from January to February that changes will be afoot, as a Sudden Stratospheric Warming (SSW) is likely to take place between roughly January 21st and February 14th that should deal a much more damaging blow to the polar vortex. It is likely to be a split, as opposed to a displacement, as per 6/9 the nine examined analogs. This should ultimately ensure that any visions of an early spring are vanquished".

The overall tenor of the month locally has not significantly changed, as the most favorable stretch for wintery weather still appears to be in the first half the month, especially centered on the second week, from about the 7th through the 14th. This idea is currently supported by long range ensemble consensus, which all agree on  storm system tracking close to the coast, which would imply primarily snowfall for northern New England, and mixed precipitation or primarily rain for southern New England.

 

 

The key change to the forecast is that the PNA should be ascending, rather than descending, considering that it reached its nadir during December instead of January, as originally forecast. This may serve to shift the warmth for the month for the month of January from its original forecast position in the northern plains, to the southeast. The forecast for the arctic remains unchanged from last fall, as the PV has survived the December assaults as predicted, and will continue to recover through most of January. All of this transition and mass flux is what makes a period of storminess near the end of the first week of the month more likely.

 

PNA (Left) EPO (Right)

 

However, the recovery of the polar vortex means that as said storminess takes place and the Pacific becomes less hostile, the polar domain becomes more hostile for wintery weather in the east.

 

 

NAO (Left) AO (Right)
 

This implies that the best change for any signifiant snows through mid January continues to appear to be across northern New England and upper New York state, as originally forecast last fall. Thereafter by mid month, the pattern is expected to turn mild with a more zonal flow, and a thaw for any locales to the north that had experienced sustained winter weather. This timeline is supported by the latest MJO composites, which show perhaps a brief flirtation with phase during the second week of January, near the time of the winter storm opportunity.

 

However, it is at this point that the tropical influences will be waning as the MJO becomes less and less of a factor towards mid month.

 

 

Thus the hemispheric pattern in the mid latitudes will become more heavily influenced by the extra tropics at this point, which will consist of a formidable polar vortex. While the official forecast is for the month to finish anywhere from +1 to +3F across the region, this will likely be modulated by the shape and character of the polar vortex, as an elongated lobe across this side of the pole would make the lower end of said rage more  likely. Conversely, a more restricted and compact vortex near the pole would mean perhaps even warmer than the forecast range. As we look towards February, all eyes will be peered to the stratosphere for any signs of disruption.

 

Hopefully I continue to off base moving forward...the hope is that the PNA really spikes and/or the PV is elongated.

[CoastalWx]

Just now, Allsnow said:

Yeah, can’t have that deep trough in Ak. Need to work on that 

It's ok. It doesn't have much if an effect on the pattern. A lobe or s/w trough really.

[40/70 Benchmark]

2 minutes ago, CoastalWx said:

It's ok. It doesn't have much if an effect on the pattern. A lobe or s/w trough really.

I see that as pretty much a non factor for January. Its going to be about the ratio between the improving PNA and deteriorating arctic.

[ORH_wxman]

17 minutes ago, CoastalWx said:

I don't mind the EPS..maybe clipper-ish? Has a decent ridge out west and a mean placement of surface  high pressure north of New England.

Yeah EPS is still totally fine but GEFS would be better. EPS actually starts retrograding the western ridge a bit at the end to a nice spot. 

[CoastalWx]

1 minute ago, ORH_wxman said:

Yeah EPS is still totally fine but GEFS would be better. EPS actually starts retrograding the western ridge a bit at the end to a nice spot. 

EPS really started looking good at the end. A compromise even would be great.

[Damage In Tolland]

6 minutes ago, 40/70 Benchmark said:

Hopefully I continue to off base moving forward...the hope is that the PNA really spikes and/or the PV is elongated.

Free base?

[Allsnow]

6 minutes ago, CoastalWx said:

It's ok. It doesn't have much if an effect on the pattern. A lobe or s/w trough really.

I just hope it’s not smoothing the trough out but when we get closer it’s stronger. The pna signal is very strong which is nice to see 

[40/70 Benchmark]

2 minutes ago, CoastalWx said:

EPS really started looking good at the end. A compromise even would be great.

Yea, PNA gets pretty aggressive....I could see that working out....2010-2011 followed the Pacific progression, with the RNA December, then handoff from arctic to PNA in January. Its a great ENSO analog so its possible

[40/70 Benchmark]

The mild December could also be a sign that la nina is assuming more east based look, too....which would be good. I am def not confident in an poor outcome for Jan.

Bottom line is that at some point we should make  ground because this season did not have a poor profile heading in.

[40/70 Benchmark]

To me, the timing is more difficult than hitting the overall character of a season.

That is tough.

[snowman19]

35 minutes ago, leo2000 said:

Typical EPS Bias with the lower heights in AK. As far as the GEFS goes I really hope it's right. Yes, many references going around this winter will be like 2014-2015. 

Yea….sure

[MJO812]

Nam keeps hopes alive

[PhineasC]

Healthy shift to a more south and progressive solution on the NAM. Not far from a mostly snow event here.

[dryslot]

3 minutes ago, PhineasC said:

Healthy shift to a more south and progressive solution on the NAM. Not far from a mostly snow event here.

Getting closer to just some flakes in the air at the end, About .25" qpf, Certainly won't ruin the pack with temps and dews in the 30's.

[PhineasC]

Just now, dryslot said:

Getting closer to just some flakes in the air at the end, Less then a .10" qpf, Certainly won't ruin the pack with temps and dews in the 30's.

Yeah, it's dampening out for sure. NAM was still kinda wound up with it at 12z so glad to see it following the GFS.

Probably end up a net gainer here if trends continue.

[Typhoon Tip]

4 hours ago, Go Kart Mozart said:

I think it was Raindance (I could be wrong) who posted research showing the HC expansion is a big deal in summer, but not winter.  As compressed as the flow is in our region, there is no such problem out west.  Could it be the compression we are experiencing is primarily a La Nina issue?

Well ... we can't think of the Earth system as having a silver bullet factor - like the HC is causing all this, or the La Nina is causing all that...

The climate system is an on-going cocktail of influences... some more at times, given the favorable setting to act.     That's A

B, the compression has been an issue across all winters now going back a decade, the majority of times, and that was regardless of ENSO state. 

 

[George001]

I see that the trough out west is going away on the models. Unfortunately the North Atlantic blocking is expected to go away as well, but if there is a big ridge out west like the long range Canadian guidance shows we won’t need much North Atlantic blocking. 2014-2015 had hardly any North Atlantic blocking but due to the ridge out west the pattern was really good, and we got buried. I still think there is a path to getting the 70-85 inches of snow i forecasted in the Boston area, and I’m not ready to give up. Plenty of winter left.

[Henry's Weather]

19 hours ago, Henry's Weather said:

Looking at the long range, if we eventually make the flip from a -PNA/NAO pattern to a +PNA/NAO pattern, we have 4 potential Archambault chances, with the both the Pacific and Atlantic changing? With all that cold to our west, we'll see something significant in the next 20 days, I'm sure of it. 

 

7 hours ago, 40/70 Benchmark said:

Just my hunch, but I have a hard time getting out of this regime without some kind of storminess....you have to figure with two nodes of that magnitude relenting (NAO and RNA) there is going to be: 1) A ton of mass flux 2) Ample supply of cold built up put west.

 

[snowman19]

36 minutes ago, MJO812 said:

Nam keeps hopes alive

How many inches of snow did you get for NYC when you extrapolated the 84 hour NAM? I’m up to 8….

[powderfreak]

41 minutes ago, PhineasC said:

Healthy shift to a more south and progressive solution on the NAM. Not far from a mostly snow event here.

Yeah that’s a good jump south.

[40/70 Benchmark]

1 hour ago, Henry's Weather said:

 

 

IDK about 4 HA events l, but I could see one moderate phase change snow event...I mentioned early Jan as a slight KU risk in my original outlook, but not feeling that.

[PhineasC]

48 minutes ago, powderfreak said:

Yeah that’s a good jump south.

GFS also slid south it looks like. 

[PhineasC]

Pretty large jump south on the ICON too. It was one of the more wound up solutions at 12z. 

[PhineasC]

Time for the Euro to piss in the cornflakes and dump an inch of rain on me. 

[Henry's Weather]

17 minutes ago, 40/70 Benchmark said:

IDK about 4 HA events l, but I could see one moderate phase change snow event...I mentioned early Jan as a slight KU risk in my original outlook, but not feeling that.

yeah I can't really see anything special, unless somehow PNA and NAO regions flex at the same time. It's pretty far into tenuous theory land, but I wonder if since the RNA has been so pronounced that when/if a regime change to +PNA occurs, we will see an increased chance of something significant just because of the magnitude of flux.

[Henry's Weather]

And it's also winter time. It snows during the winter. Our pattern isnt exactly like 1972-3, 2006-7, 2011-12 or similar years, so just probabilistically, it will snow. At some point. Maybe.

[CoastalWx]

Gfs won’t give up haha.

[weathafella]

1 minute ago, CoastalWx said:

Gfs won’t give up haha.

It will by 11 tonight