Winter 2019-2020: Modified Modoki

[ORH_wxman]

9 minutes ago, Dr. Dews said:

Not disagreeing, but isnt there a reliable site closer to Winthrop than Hingham?

Winthrop coop is where the measurements were taken from 2010-2018....but not anymore...it is defunct now. That's why we had the disaster "new location" last winter.

[Baroclinic Zone]

So much anger over snow measuring.

[Ginx snewx]

So basically a 15/16 winter, meh

[Ginx snewx]

Rain dance wx was told several times last year the Boston number was bogus

[weathafella]

is there a new measurement system at Logan this winter?

[weathafella]

4 hours ago, Baroclinic Zone said:

So much anger over snow measuring.

Climate records for a major city are important.

[raindancewx]

From what I remember, if Boston had actually gotten 3-6" or whatever it was last November at the official site, instead of nearly nothing, I would have been within 2-4" of what I had forecast for Boston.  If you think it's 40" instead of 27", I'm just low instead of high by a few inches last year, so it doesn't really matter to me. 

Looking at the forecasts of others, I do think it would be prudent to find predictive variables that are objectively known ahead of winter for precip/temps/snow, other than say, ENSO or the PDO or whatever. Something like a precip pattern in Summer. You guys really live or die with the teleconnection indexes - AO, NAO, PNA, EPO - etc. You can probably predict...most of them correctly in any winter, but all is a tall order. My stuff is designed to be something like 1/3 data mining, 1/3 statistics, 1/3 global patterns. I find that there are like a 100 ways to match on any blend of ocean/atmospheric/solar variables, but it's much harder to have those match and get your weather to match day and date for an extended period - so that's what I try to do. Matching the highs/precip patterns for a long-time with the oceans/solar stuff seems to be a way to lock onto the MJO signal for a few months if nothing else.

[40/70 Benchmark]

7 hours ago, Ginx snewx said:

So basically a 15/16 winter, meh

No. Not that warm.

[Baroclinic Zone]

11 hours ago, weathafella said:

Climate records for a major city are important.

Are you implying they didn’t measure accurately?

[EastonSN+]

22 minutes ago, CoastalWx said:

Zzzzzzzz  ahead 

Yep. Disappointing given the teleconnections.

[weathafella]

1 hour ago, Baroclinic Zone said:

Are you implying they didn’t measure accurately?

In implying that their numbers don’t even remotely match the surrounding close by stations after allowing for normal differences.   I don’t know how they measure but i do know that the NWS knows of this issue but probably have their hands tied so to speak.

[Ginx snewx]

7 hours ago, 40/70 Benchmark said:

No. Not that warm.

Similar snowfall distribution.  Hope you are wrong, no offense 

[CoastalWx]

17 minutes ago, weathafella said:

In implying that their numbers don’t even remotely match the surrounding close by stations after allowing for normal differences.   I don’t know how they measure but i do know that the NWS knows of this issue but probably have their hands tied so to speak.

Oh it’s an issue the NWS knows about. We are going to try and make snow measurements great again for Boston. 

[40/70 Benchmark]

4 hours ago, Ginx snewx said:

Similar snowfall distribution.  Hope you are wrong, no offense 

Its a little more...forecast is slightly above. That season was normal to slightly below.

We need second half blocking....that is the upward variance. Pacific won't be epic like 05 and 15..at least not for the whole season..

[dryslot]

15/16 was a well below normal winter up here according to my records, Hard pass.

[40/70 Benchmark]

3 hours ago, dryslot said:

15/16 was a well below normal winter up here according to my records, Hard pass.

Same...thankfully, I'm not forecasting that.

[40/70 Benchmark]

Updated December thoughts...not much change.

https://easternmassweather.blogspot.com/2019/11/wet-holiday-travel-week-leads-to-onset.html

[40/70 Benchmark]

December Review

 

The month of December has largely evolved as anticipated, with a very active storm track and near normal to slightly negative monthly temperature departures throughout most of New England. These departures should not change much over the final few days given the current forecast.

 

Note our thoughts in relation to December that were expressed in the 11/13/19 Eastern Mass Weather Winter Outlook:

 

"The month of December should be both active and variable. A robust PNA should be the primary driver of the pattern, thus central and northern New England should see the most robust snowfall anomalies. While the PV may encounter some disruptions, it should recover, which may ultimately prove more inimical to the development of early season blocking, which is not climatologically favored, regardless. The NAO should have some increased moduality, and a transient negative phase could link with the PNA to create a major early season storm. Favored period being from 12-5 to 12-19.

-1 to -2 departures north of Concord, NH, around normal down to 40N, and up to +1 points southward". 

-Eastern Mass Weather 11-13-19

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Obviously the month did not verify as cold as the composite across the Eastern half of the nation, nor was it supposed to, as the normal to -2 departure that was explicitly mentioned implied. The potential for a major winter storm did indeed come to fruition, however it occurred two days prior to the outlined two week window.  This system likely contributed to one slight discrepancy with regard to the monthly snowfall departures, as the heaviest snowfall anomalies ended up verifying over south central New England, as opposed to north central New England, as forecast. However the real proverbial "fly in the ointment" was the PNA forecast, which was predicted to be robust and was merely modestly positive, as evidenced by the cooler anomalies over the Pacific northwest than implied in the composite. .

 

 

 

The polar domain behaved largely as anticipated, with increased variability that manifested in an active storm track.

 

 

Although the polar vortex did endure some minor assaults early on in the month of December, as suggested in the winter outlook, it has also proven every bit as resilient as anticipated. Thus the notion that the first half of December would be biased cold, followed by a mild second half of the month that would herald in a rather protracted winter reprieve has also come to fruition.

Here is a review of the expressed thoughts from 11-13-19 in relation to the behavior of the polar fields.

 

"The seemingly favorable antecedent conditions for the disruption of the PV in conjunction with both the observed north atlantic tripole over the summer, as well as the anticipated favorable Hadley cell configuration in association with the ongoing modestly warm ENSO event all favor increased blocking. However they are interpreted as being suggestive of perhaps one month during the coming period featuring one or more major and sustained blocking episodes. This will likely occur later in the season because conditions should be hostile for the development of sustained blocking during the first half of boreal winter 2019-2020 due to the considerable initial intensity of the PV, in conjunction with the delayed descent of the easterly QBO phase. This does not preclude intervals of negative NAO and bouts of wintery early season weather, owed to the elongation of the PV that is conducive to periodic and transient cold intrusions, as well expected volatility of the NAO modality. It is also important to note that while conditions appear favorable for at least minor disruptions to the PV,  its recovery from any such occurrence is expected to be both proficient and timely. This is due in part to climatology favoring only minor assaults early in the season, as well as the anticipated resiliency of a potent PV denoted by +AO conditions presently observed within the polar stratosphere. Such a recovery period after any potential assault would likely lead to a protracted mid winter thawing period as the vortex reconsolidates and possibly becomes more circular in nature.

 

Sure enough, the polar vortex is fairly stout, though elongated, and well centered in the vicinity of the pole at present, which is indicative of a positive AO.

 

 

And there are signs that it remain as such for a rather extended period of time.

 

 

January Preview

There are not significant changes to the though process regarding the month of January.

 

 

"January remains fairly active, at least throughout the first half. The PNA ridge begins to erode, however the PV may be undergoing some dysregulation, so the PNA relaxation may be offset to a degree. Departures normal to -1 NNE, normal to +1 for SNE and the mid atlantic." Eastern Mass Weather- 11-13-19

 

 

However it does now appear increasingly likely that the polar fields will remain fairy hostile to extended periods of cold and snow, as the latest forecasts have confirmed the Eastern Mass Weather notion of the polar vortex continuing to grow more consolidated and circular throughout the first third of January.

 

 

Predominately +NAO Indicative of Strong Polar Vortex Throughout January

 

Predominately +AO Indicative of Strong Polar Vortex Throughout January

 

In addition to the hostile polar domain, the expected development of an RNA has already ensued and is expected to remain prevalent through at least the month of January, all but ensuring a relatively mild month for the northeast.

 

RNA Favors Southeast US Ridge this January

 

The correction vector with regard to the slightly above normal January forecast issued this past fall would seem to be pointed in the milder direction. Snowfall in southern New England will likely be below normal this month, with normal snowfall across central New England and perhaps above normal in norther New England. This stratification of the monthly snowfall gradient will be owed to a strong polar vortex and RNA favoring a mean southeast US ridge in conjunction with an eventual relaxation of the deep trough currently positioned in the vicinity of Alaska. This abatement should allow cold to remain entrenched in Canada, thus providing a reservoir of cold to be tapped by storm systems for at least northern areas.

 

Relaxation of Alaskan Trough Reflected by More variable EPO

 

This progression is also favored by the MJO, which is forecasted to flirt with phase 7, before relaxing and remerging in phased 4 and 5 about a week into January.

 

 

 

Phase 4:

 

 

 

And Phase 5 of the MJO in the second week of January also teleconnect to the aforementioned pattern, which features a predominate west coast troughs and southeast ridge:

 

 

 

 

Finally, seasonal guidance confirms:

 

Both the Canadian SIPS:

 

 

 

 

And the European monthly guidance confirm:

 

 

 

Conclusions

 

The month of January looks fairly mild, and should not produce very much in the way of significant snows or severe cold for southern New England. However much like last season, what opportunities do present themselves should favor the interior and central/northern New England, as the cold will enter through the western US, and only methodically bleed eastward  near the Canadian border in a modified state. The best chance for the foreseeable future appears to be with a system approaching around January 5th, as heights in the vicinity of Alaska and the polar domain appear to relax as much as they appear that they will for most of the next month. The interior and northern areas are of course still favored, but the system may feature some mixed precipitation for coastal southern New England.

 

Ensemble consensus for this system exists amongst the European ensemble suite:

 

 

 

The GFS ensemble package:

 

 

 

 

And the Canadian product:

 

 

 

Second Half Revival of Winter Likely

 

While it does appear that January may perhaps verify even milder than originally anticipated, the forecast for the balance of winter remains unchanged, as a more favorable polar field should negate what may remain a hostile Pacific. This is supported by the notion that the QBO (+5.07 as of November) should be neutralizing in February, the Eastern Mass Weather analog composite from the winter outlook, as well as some of the current seasonal guidance.

 

For February:

 

 

 

 

 

And especially March:

 

[40/70 Benchmark]

Had the right idea on the extended mild period from around the holidays through January, but it was more extreme than I had thought.

 

Protracted Mid-Winter Thaw More Extreme Than Expected: February Throughts

January Review

Here are the expectations for the month of January as expressed in the 11-13-19 Eastern Mass Weather Winter Outlook.

 

"January remains fairly active, at least throughout the first half. The PNA ridge begins to erode, however the PV may be undergoing some dysregulation, so the PNA relaxation may be offset to a degree. Departures normal to -1 NNE, normal to +1 for SNE and the mid atlantic".
 

Eastern Mass Weather 11-13-19-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Here is how the month verified:
 

 

 

 

While the general theme of a mild month was correct, the southeast ridge was more prevalent than expected and the Pacific more hostile than anticipated. Thus the month was even milder than forecasted.
 

February Preview

Last fall, Eastern Mass Weather expected that February would also be mild due in large part of a persistent RNA pattern. However the development of blocking late in the month is more precarious.

"Full-fledged RNA ensues for February, as any influence that weak el nino or warm-neutral coupling had established may die. In The polar vortex will need to relent, or this will be a very mild month with the storm track west. +1to +2 throughout the northeast. +2 to +3 in the mid atlantic. Beware an eventful president's day should blocking establish itself. February 17-March 2nd may be conducive".

Eastern Mass Weather 11-13-19-

 

 

"Winter will be waning long before month's end in the absence of high latitude blocking, given the hellacious southeast ridge in place. However at least some sustained blocking is likely.  Since there will be cold air lurking to the north at the very least, this does not look like a "dead-ratter", even without blocking". 

Eastern Mass Weather 11-13-19-

How quickly winter wanes should be dependent on the degree to which the polar vortex can become consistently dysregulated, however as it appears to remain rather resilient at least throughout the first half of February.
 

Polar Evolution

The polar vortex is obviously stout and centered near the pole to begin the month of February. 

 

 

 

 

However it does look to withstand a minor assault next week, which may coincide with a wintery overrunning threat.

 

Here is the forecasted behavior of the polar domain, which is congruent with the forecasted behavior of the polar vortex.
 

The winter storm threat next week that is concurrent with the relaxation of the well defined polar vortex is apparent on ensemble guidance. The battle between the pressing cold and the southeast ridge owed to the RNA is on. However the descending EPO should ensure a cold air source.

 

 

Snow or a mix (sleet, rain, ice) is likely to the north of the Mass pike, and a mix or rain is likely south.

 

The following week, or the second week of February features a recovering polar vortex, which has been a theme throughout boreal winter 2019-2020.

 

But there are some signs that it may endure at least a slightly more sustained attack beyond mid month, which is when conditions should become more favorable for the second major winter storm of the season between February 17 and March 2. The overall tenor of March may very well be contingent upon how quickly and proficiently the polar vortex can recover yet again.

[40/70 Benchmark]

February Recap; March Preview And Late Week Winter Storm Potential

 

February Review

Yet another mild month is in the books, as the January through February mid tier of winter has been one of the warmest on record across the northeastern US. While a mild middle portion of winter was anticipated here at Eastern Mass Weather, it has verified significantly milder than expected, which was a potential specified last fall in the event that the robust polar vortex did not weaken.

Here are our expressed thoughts from last November:

 

"Full-fledged RNA ensues for February, as any influence that weak el nino or warm-neutral coupling had established may die. In The polar vortex will need to relent, or this will be a very mild month with the storm track west. +1to +2 throughout the northeast. +2 to +3 in the mid atlantic. Beware an eventful president's day should blocking establish itself. February 17-March 2nd may be conducive."- Eastern Mass Weather 11-13-19

 

Obviously the polar vortex has not relented as intimated it would. This is the reason that winter has never recovered and the identified 2-17 to 3-2 window will fail to produce a major winter storm, since the Pacific has remained hostile, as anticipated. The result is that the northeast has verified closer to +3 to +4 above average for the month of February, as opposed to the forecast of +1 to +2F. The mid atlantic +5 to +6F, instead of the expected +2 to +3. 
 

 

While February did in fact verify slightly warmer than expected, the forecast was much more accurate than the absurdly warm January 2020, which was one of the warmest winter months in recorded history. As tempting as it may be to declare winter officially over, old man winter still has one final chance for redemption.
 

March Preview

The eastern Mass Weather forecast for March appears largely on track, with some warmer potential.
The expressed narrative sentiment from this past fall is as follows:
 

"Winter will be waning long before month's end in the absence of high latitude blocking, given the hellacious southeast ridge in place. However, at least some sustained blocking is likely.  And since there will be cold air lurking to the north at the very least, this does not look like a "dead-ratter", even without blocking. Temperatures should average around 1 degree below normal in New England, and around normal in the mid atlantic".

 

The forecast will likely verify somewhat warmer than the forecast -1 departure, since again, the polar vortex has remained stout and no blocking of any kind looks to materialize. The outlook hedged on at least some modest blocking. But the notion that there should be cold air lurking nearby throughout Canada does indeed appear valid, so there should be continued opportunities for snowfall for at least northern New England. And southern New England has a window of opportunity before milder weather returns towards mid month, as implied last fall in the absence of blocking.
 

Pacific Flex March 6-10

Ironically enough, it appears as though a several day relaxation of the predominately hostile Pacific regime appears to set the stage for a potential winter storm around March 6.

 

 

 

 

 

 

 

 

While the north atlantic and arctic, which were forecast to become more favorable around this timeframe, remain unfavorable for winter storms across southern New England. However, despite the largely unfavorable north atlantic, long range guidance is hinting that a pseudo 50/50 low feature may be fortuitously timed (or unfavorably, dependent on perspective) with the approaching system.

 

This is denoted on the European ensemble guidance:

 

 

 

The Canadian:

 

 

 

 

And the GFS ensemble:

 

 

 

 

It is unlikely that winter is over given the climatology of seasons that have produced major early December snowfalls such as this one, so stay tuned-

[MJO812]

Nice thought out forecasts. Too bad this winter sucked for many.

[40/70 Benchmark]

https://easternmassweather.blogspot.com/2020/04/march-verification.html

March Review

 Here we our expressed thoughts relative to March back in November:

 

"Winter will be waning long before month's end in the absence of high latitude blocking, given the hellacious southeast ridge in place. However, at least some sustained blocking is likely.  And since there will be cold air lurking to the north at the very least, this does not look like a "dead-ratter", even without blocking. Temperatures should average around 1 degree below normal in New England, and around normal in the mid atlantic". -

Eastern Mass Weather 11-13-19

 

 

 

Here is how the month actually verified in terms of temperature anomalies:

 

The month was much milder and featured less snowfall than anticipated across southern New England. This due to the fact that while the RNA pattern was every bit as prevalent as anticipated, the  expected blocking did not materialize until the tail end of the month.

 

 

This had the most profound impact on the southern New England region, where the mean monthly temperature departure averaged near +4F, as opposed to the forecast -1 anomaly. The forecast was much more accurate across northern New England, where the nearby cold created more opportunities for snow, as well as the mid atlantic, where milder weather was expected.

[40/70 Benchmark]

On 11/13/2019 at 10:01 PM, raindancewx said:

Your percentage listed for Boston is 80-27/80. Comparing the error to the theoretical total (80") doesn't make any sense. If I told you your kid was going to be 8 feet tall and the kid ended up 3 feet tall would you call that a 60% error? That's what you did. It's closer to a three fold error. I had 35" in my blend last year, and even that is a 30% error for Boston if you use real math.

You picked average snow this year, so mathematically you don't have to worry anyway, it's more or less impossible to be as wrong as last year for Boston, so in that sense at least I'm sure you have a much better forecast.

I don't really care what people forecast, but if you are going to grade yourself, you need to do (expected-actual)/(actual). You did (expected-actual)/(expected) which doesn't mean anything.

 

 

Thanks again for that brief tutorial, as my math skills have always been very deficient, which is a large reason why I never pursued a career in weather....much to the chagrin of family and friends. Hey, judging by these past two seasons, I made the right call. LOL

Going back through all of my seasonal verification posts and making these corrections.

 

 

[40/70 Benchmark]

Verification:

https://www.blogger.com/u/1/blog/post/edit/2820149554058213224/3271427891031056834

Final Grade is a D+.

Here is the brief version:

Abstract

Although the 2019-2020 seasonal forecast did have some forecasting victories, such as the development of an el nino, a cold and snowy start to the season in December and the rapid warm up as the holidays approached, it ultimately left a great deal to be desired. The 1969-1970 season was utilized as a primary analog with the notable caveat that not as much seasonal blocking was anticipated in the aggregate. But rather the parallel between the two seasons was made due to the postulation that the winter of 2020 would eventually develop that same proclivity to develop high latitude blocking on the heels of another meager el nino, which the 1969-70 season did. However, this season exhibited that one month that would feature the propagating poleward heat flux necessary to induce significant blocking during the second half of the season, as opposed to the 1969-70 analog, which featured the most stout blocking in January. The very mild middle of the season was expected, but it was even more protracted and warmer than forecast. Couple this with the fact that the crucial development of blocking took several weeks longer to materialize than forecast and what had began as a very promising outlook devolved into our worst yet. And by a wide margin at that.

 

 

December-March Forecast Review 

Here is the DM period:

What could be gleaned from this is that there would usually be a cold source expected to at least be nearby even in the event that sustained blocking did not materialize, which it did not, until spring.

 

 

D-M Seasonal Composite

 

December-March Outcome

D-M Outcome

 

 

 

The details for this past season are as follows

 

Snowfall was under forecast at none of the 15 cities.

Snowfall was over forecast at all 15 cities.

Snowfall verified at none of the cities.

 

City	Predicted Snowfall	Actual	Forecast Error
Boston, MA	45-55”	15.8"	+185%
New York, NY	20-30"	4.8"	+317%
Philadelphia, PA	17-27"	0.3"	+5,667%
Baltimore, MD	15-25”	1.8"	+733%
Washington, DC	15-25”	0.6"	+2,400%
Albany, NY	65-75”	49.7"	+31%
Hartford, CT	50-60”	29.1"	+72%
Providence, RI	40-50”	13.2"	+203%
Worcester, MA	70-80”	44.9	+56%
Tolland, CT	60-70"	31.4"	+91%
Methuen, MA	65-75”	44"	+48%
Hyannis, MA	20-30”	5"	+300%
Burlington, VT	80-90"	69.6"	+15%
Portland, ME	70-80”	59.6"	+17%
Concord, NH	65-75”	46.5"	+40%

 

 

 

 

Index Value	Predicted '19-'20 DM   Value Range	Actual  '19-'20 DM Value	Forecast Error
Pacific Decadal Oscillation (PDO)	0 to .30	-.91 (DF)	+.91
Perennial North American Pattern (PNA)	.15 to .45	-.57	+.72
ENSO	Weak Modoki El Nino   (0.3 to 0.5C ONI) (NDJ)	0.6C JFM ONI .52 Modoki	Predicted Peak two months early, and .01 too cold. Modoki value +.02 greater than forecast.
(J-M) East Pacific Oscillation (EPO)	-.15 to -.45	+.65	+.80
Arctic Oscillation (AO)	0 to -.30	+2.22	+2.22
North Atlantic Oscillation (NAO)	-.15 to .15	+1.20	+1.37

 

The mean forecasting error with respect to snowfall was an unfortunate 678.3%, which is by far the worst snowfall outlook dating over six seasons.

 

Final Grade: D+

 

The mean forecasting error with respect to the previous seasonal snowfall outlooks are as follows:

2018-2019: 90.4%

2017-2018: 13.2%

2016-2017: 35.3%

2015-2016: 71.4%

2014-2015: 10.9%

 

Six season running mean error: 149.9%

24/86 (27.9%) of snowfall outlooks have been under forecast.

46/82 (56%) of snowfall outlooks have been over forecast.

16/82 (20%) of snowfall outlooks have verified within the forecast range.

This just in: Forecasting snowfall at very extended leads is difficult.