Winter 2019-20 Preseason Discussion

[CAPE]

14 minutes ago, frd said:

Fits the Seasonal outlook.

For those that follow the weeklies may I suggest......... some Zoloft 

 

Its typical weeklies- overall ambiguous, but mostly suggestive of a continuation of the pattern depicted by the 0z run it is initialized off of. So generally a continuation of a SE ridge, although it waxes and wanes. It's not a completely terrible look overall, but nothing stands out to be overly excited over.

[frd]

2 minutes ago, C.A.P.E. said:

Its typical weeklies- overall ambiguous, but mostly suggestive of a continuation of the pattern depicted by the 0z run it is initialized off of. So generally a continuation of a SE ridge, although it waxes and wanes. It's not a completely terrible look overall, but nothing stands out to be overly excited over.

Focusing just on wavelengths , there may be some surprises as we enter December. The PMM has an interesting association once wavelengths change. Posted on that a while ago but since then the PMM has only gone higher. 

There have been some years, when looking in the past, where the pattern did change later in November and brought a favorable wintry period to our area in early December lasting into the middle of the month. 

Maybe that shows up in the weeklies once past early November.   

[frd]

@C.A.P.E. 

Another area to look at is the TNI. 

When you look at this ENSO metric it is very difficult to find a usable analog because the present value of - 3 there have only been a handful of times it has been that negative, as pointed out on the recent blizzard of 96 blog.

I looked back to 1946 and doing a quick scan only saw the value at - 3 or lower  four times. 

2002 and 2004 , I believe they both had cold Decembers . 

. 

 

[clskinsfan]

On 10/20/2019 at 8:15 AM, poolz1 said:

Hopefully a preview....

If the GEFS is correct, the MJO will have been in 8/1/2 for 40 days.

I have been checking on the long range Aussie MJO forecasts the past couple of weeks. According to that 7-8-1 may be the norm this winter with some time in COD during relaxation periods. I dont think the long range MJO forecast is very accurate. But I could live with a pattern like that.

[poolz1]

Some interesting comparisons to 13/14 this Oct.  The end of 2013 had a similar PDO.  Slightly Neg.

Also, note the similarities at H5.  2013 had a torch Dec, which some are predicting this season, but the backloaded winter made up for it.  I am sure there are differences to 13/14 if one were to dig deeper into everything but I thought this was interesting. 

[Winter Wizard]

One quick note: it's definitely a stretch to call December 2013 a torch. Most places in the Mid-Atlantic finished the month right around average and that was largely skewed by a torch around 12/20. The first half of the month was below normal and the week of 12/8 brought three separate snow events to the Baltimore/DC metro, all of which featured WSW in the LWX zones. In fact, going off of the discussion yesterday in the medium/long range discussion thread, it's a good example of when having a strong SE ridge works in our favor since it shifted the baroclinic zone northward enough to get us in the action, but thanks to the strong -EPO, we remained on the right side of the gradient. 

[poolz1]

@Winter Wizard Looking at it,  you are correct about Dec.  To be honest, I went off memory which isnt a great idea these days!  I probably remember it as a torch due to the mini torch just before the holidays.  

[BTRWx's Thanks Giving]

7 minutes ago, poolz1 said:

@Winter Wizard Looking at it,  you are correct about Dec.  To be honest, I went off memory which isnt a great idea these days!  I probably remember it as a torch due to the mini torch just before the holidays.  

It wasn't mini.

[WxUSAF]

Good twitter thread from HM and others this evening. This good tidbit:

 

[CAPE]

PDO looks like it might be trending towards the warm phase. Always difficult to read the significance for winter at this juncture, but this certainly isn't a bad sign IMO.

 

[poolz1]

PDO looks like it might be trending towards the warm phase. Always difficult to read the significance for winter at this juncture, but this certainly isn't a bad sign IMO.
 

Also note the decrease in the +IOD. Implications? No idea... Besides the warming just off the west coast I do like 1+2 remaining cold relative to the central PAC.

[poolz1]

 

[frd]

Great read from @40/70 Benchmark over in the New England forum. 

His main winter outlook is set to be released on 11/12/19 .  

 

OCT

24

 

 

Confidence Grows in Late, Marginal El Nino

Rapidly Evolving ENSO

At the turn of the month, when ENSO neutral conditions were all but a foregone conclusion for winter 2019-2020, it was noted on this site that the warmth in ENSO region 4 was a fairly strong climatological indicator of a burgeoning el nino. As the month of October has evolved, the support has grown stronger. As of October 16th, region 1.2 has increased from -1.0c to -0.2c, region 3 from -0.1 to +0.4c, region 3 from +0.4c to +0.8c and region 4 from +0.9c to +1.1c. Not only has the western flank of region 3.4 and 4 continued to approach moderate levels, but the eastern flank has also began to warm. The implication of this are twofold:
1) Although it will likely take until the NDJ tri monthly period to verify, a weak el nino ONI will likely by achieved. Since 1990, 1991 (strong), 1997 (super), 2002 (moderate), 2009 (moderate) and 2015 (super) have registered equal or greater magnitude of warmth on the western flank of the ENSO regions in mid October. Significant el nino events ensued in all five of these seasons.
2) The subsurface warmth is penetrating the eastern regions of 3 and 1.2, thus a decline in the modoki value has ensued.
Even a cursory glance at the subsurface provides a clear depiction of why this has taken place, and will likely continue.

Morphologies Driven by Subsurface

Much like the fall of 2018, not only are we observing a continued trend toward a marginal el nino, but we are also seeing it build from west to east.

 

 

 

 

Thus the structure is gradually becoming more cannonical as it develops. 

 

The continuation of this trend is not only portended by the translation of the warmest subsurface waters eastward through region 3.4 and towards region 3, but also by modoki guidance.

 

 

Note that on the annotation above, the current burgeoning warm ENSO event registers as roughly +.75c on the modoki scale, which is strongly modoki on par with the 1977-1978 event. However as the warmer subsurface waters continue to translate eastward, it is forecast to descend to approximately a +.40, which registers as moderate and on par with seasons such as 1979, 2006 and 2015. As the moderate classification would suggest, the result for the ensuing winters is very variable across the area, ranging from meager snowfall to the snowiest winter on record. While 2015 appears to be the best ENSO match at this time, one important distinction is that this particular event grew into a modoki, whereas this event, much like this past season's, is forecast to trend potentially more cannonical as it evolves.

Conclusions

This will be the final installment before the Eastrern Mass Winter outlook is released on 11-12-19, but there remains a great deal to ponder in the interim. Although the Climate Prediction Center has curiously reduced the odds of an el nino event to a mere 29% as of the Friday 10/18 update, 

 

we have grown ever more confident of a very delayed and modest el nino event that will likely peak in the NDJ tri monthly timeframe. The warm ENSO event will likely register moderately on the modoki index during its tri monthly peak, which implies mixed results with regard to its implications for winter. 

 

 

 

SEASON	Peak Tri Monthly ONI Value	Peak Tri Monthly Modoki Value	Boston, MA Snowfall	Wilmington, MA Snowfall	Worcester, MA Snowfall	New York City Snowfall	Baltimore , MD Snofall
1951-1952	+1.2C SON	+.04	39.6”	62.5"	63”	19.7”	14.1”
1953-1954	+.08C  OND	+.19	23.6”	23.5"	31.2”	15.8”	22.1”
1958-1959	+.06C NDJ	+.52	34.1”	52.7”	64.7”	13.9”	4.0”
1963-1964	+1.4C OND	+.43	63”	91.7”	66.6”	44.7”	51.8”
1968-1969	+1.1C DJF	+.92	53.8”	86.5”	75.7”	30.2”	18.6”
1969-1970	+.09C SON	+.20	48.8”	74.6”	72.1”	25.6”	21”
1976-1977	+.09C OND	-.14	58.5”	97.3”	74.5”	24.5”	11.1”
1977-1978	+.08C OND	+.79	85.1”	99.5”	85.9”	50.7”	34.3”
1979-1980	+.06C NDJ	+.43	12.7”	19.9”	19.1”	12.8”	14.6”
1986-1987	+1.2C NDJ	+.52	42.5”	77.7”	93.6”	23.1”	35.2”
1994-1995	+1.1C NDJ	+.69	14.9”	22.5”	24.9”	11.8”	8”
2002-2003	+1.3C OND	+.48	71.3”	86.8”	117.3”	49.3	58.1”
2004-2005	+.07C OND	+.55	86.6”	107.5”	114.3”	41.0”	18.0”
2006-2007	+.09C OND	+.32	17.1”	34.5”	49.1”	14.7”	9.1”
2014-2015	+.07C NDJ	+.49	110.6”	115.5”	119.7”	53.8”	28.4”
2018-2019	+.09C OND	+.52	27.4”	47.5”	51.4”	20.5”	18.3”

 

 

The best ENSO analog just so happens to be the snowiest winter on record for the vast majority of Massachusetts, given both the anticipated intensity, delayed onset and moderate modoki value of the developing warm ENSO event. However this particular event has developed a bit later, and is also descending in modoki value, as opposed to ascending as the 2014 event did. We will explore possible implications of these subtle differences, as well as a myriad of other global factors that will account for the composite variability in the winter outlook set for release on 11/12/19

 

[40/70 Benchmark]

Love this thread....lots of good stuff in this forum.

[anotherman]

9 hours ago, WxWatcher007 said:

I don’t recall any kind of torch in Dec 2013, but living in DC proper, winter didn’t start until right after the new year. Those events were not really measurable where I was. Very nice for other areas though.

Boy, what a winter that was. We’d all sign in a heartbeat for a repeat. 

There was a torch but it was short lived.  Right before Christmas.

[frd]

This is a great visual , simply click the image for a close up and scroll 

You can see some of the things Ray spoke about in his update.  

The kelvin waves,  as Ventrice has posted on the past month, are having an effect. 

The warming in general and the Eastern Areas warming slightly. 

I am still very interested in the TNI as well. 

 

 

[frd]

Cool animation , simply happy to see we are gaining snow coverage up North, pretty much in all areas. Also, note the big gains in Eastern Canada later in the  loop.  Courtesy 33andrain by Snowy Hibbo  

<<

Posted 5 hours ago

Large increase in the Siberian and North American snow cover over the next week or so FWIW.

And this happens as Arctic sea ice is at a record low...

>>>>>>>

[40/70 Benchmark]

On 10/22/2019 at 6:57 PM, WxUSAF said:

Good twitter thread from HM and others this evening. This good tidbit:

 

Agree...I don't see the typical lackluster December generally associated with el nino.

[Maestrobjwa]

1 hour ago, 40/70 Benchmark said:

Love this thread....lots of good stuff in this forum.

Indeed...(what's going on in your forum? Lol Been lurking back in there to see any winter discussion, but haven't seen any for like a week!)

[40/70 Benchmark]

1 minute ago, Maestrobjwa said:

Indeed...(what's going on in your forum? Lol Been lurking back in there to see any winter discussion, but haven't seen any for like a week!)

Everyone was whacking it to the big nor easter last week.

[psuhoffman]

2 hours ago, 40/70 Benchmark said:

Love this thread....lots of good stuff in this forum.

Love your work.  I would love your thoughts on this regarding modoki nino.  When there was a pretty heated debate online about nino classification last year I looked into it a bit and found some pretty convoluted results.  It seems initially, according to papers published in the 2000's "modoki" was used to describe any nino that "originated" in the central pacific and propagated eastward, as opposed to the classical nino which originates off South America and propagates west.  More recently there now seems to be different definitions, one that requires the water to remain colder to the east of the central pacific.  This is creating a lot of confusion imo around the discussion wrt nino types.  2002/3 and 2009/10 for instance, are generally considered modoki but both evolved into a more classic basin wide looking nino for a large part of those winters.  2006/7 is even harder to classify as it started in the fall as a classic east based nino and then evolved opposite of normal into a modoki looking nino by late January/February.  It is harder to evaluate some of the older nino's with limited data but from the last 30 years, it seems only 94/95, 04/05, and 14/15 were purely modoki and stayed modoki through the winter period by the second newer classification of modoki nino.  02/03 and 09/10 started as central based and then propagated eastward in December before fading back into a modoki look again in spring.  2006/7 evolved completely opposite of a "typical" modoki.  

Then there is the issue of how those differences impact the pattern.  It's hard to draw firm conclusions with such a small sample size. But at least here in the mid atlantic, our two best results 2003 and 2010 were years where the modoki evolved into a more east based look for a time.  2005 and 2015 did have some similarities in that they were both the most consistently modoki in nature and both had a somewhat similar pattern in where they focused the core of the cold and snow over new England.  But then what do we do with 1995?  Perhaps throw it out as an outlier?  And what of 2006/7?  And of course luck and other influences have an impact too.  2006/7 started awful but then had a pretty good run of cold in Feb and Mar with several opportunities but most failed for the urban corridor.  2004/5 could have easily ended better for the mid Atlantic with several good threats that failed to maximize potential.  

I am left unsure exactly how to parse the data.  If we start breaking the enso into such detailed events we end up with such small sample sizes its hard to get meaningful results.  If we look at the whole group we get such varied output its also hard to get meaningful results.  What is obvious is that having a nino in general increases the odds of above normal snowfall, at least here in the mid atlantic, and that having a moderate nino is the best to really stack the deck in favor of snowfall.  But beyond that, it seems to get really ambiguous or inconclusive, at least from my initial look at the data.  

[yoda]

Fascinating and intriguing... Texas and Oklahoma panhandles have WWA's up for snowfall in late October... wonder when the last time that happened.  And its not for just a "dusting" either... its a nice amount of accumulated snow forecasted... here's one of the WWAs:

URGENT - WINTER WEATHER MESSAGE
National Weather Service Amarillo TX
959 AM CDT Thu Oct 24 2019

...Snow Expected Across the Texas and parts of the Oklahoma Panhandles...

Snow is falling Cimarron County in the Oklahoma Panhandle and the
western stack of the Texas Panhandle. Additional snow bands are
expected to form across the southern Texas Panhandle, with brief
heavy snowfall that could cause reduced visibility in area
roadways. There may even be rumbles of thunder in association with
the snow.

TXZ007-019-242300-
/O.EXA.KAMA.WW.Y.0012.191024T1500Z-191025T0600Z/
Moore-Donley-
Including the cities of Dumas and Clarendon
959 AM CDT Thu Oct 24 2019

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 1 AM CDT FRIDAY...

* WHAT...Snow expected. Total snow accumulations between 2 to 4
  inches. Winds gusting as high as 45 mph.

* WHERE...Moore and Donley Counties.

* WHEN...From 10 AM this morning to 1 AM CDT Friday.

[40/70 Benchmark]

@psuhoffman very good point. Easy to drive yourself crazy, and dillute what is an already paltry sample size of data by endeavoring to assign more specific criteria in binning ENSO events. 

I have always interpreted the data as moderate el nino favoring mid atl most (stronger STJ, more miller a) and weak favoring sne most (More n stream dependent..miller b). Modoki is just better for the east coast in general because the central PAC source of forcing teleconnects to a weaker PAC jet, more PAC ridging and polar blocking. As far as modoki goes, I believe that it is best not to crudely designate or generalize as either modoki or cannonical, but rather utilize a sliding scale akin to that which is utilized to assess intensity/ONI....ie +1.0 modoki value is strongly modoki, +.50 to +1.0 is moderately modoki, and under +.50 minimally modoki hedging towards cannonical. Very few events register as negative, but those that do are also powerful, such as 1982, 1997 and 2015....1976 being the exception, as it was modestly negative and peaked as weak ONI. The catch is that the structure of ENSO is usually relatively fluid, thus assessing and assigning a numeric value at any given, arbitrary point in time is a fool's errand because it provides but a mere snapshot at random point. My aim is to assess this "snapshot" and assign a numerical value to denote its place on the modoki vs cannonical continuum during the apex of its ability to manifest itself into the hemispheric regime and modulate forcing schemes. This is during peak ONI intensity, which will also usually coincide with maximum bimonthly MEI. IOW, if the el Nino peaks during the OND tri monthly period, calculate the mean of those three monthly modiki values to assign a seasonal value.

Remember this...generalizations and meteorology do not mix well, especially within the context of this burgeoning frontier science referred to as seasonal forecasting. Always keep an open mind and be ready for anything. The moment that your throught processes become too rigid, you fail and fail badly, as I did last season.

[40/70 Benchmark]

Just now, 40/70 Benchmark said:

Note regarding 2014-2015...it actually started more basin wide, and trended into a modiki. There were some pretty toasty eastern regions late summer/early fall...but by peak ONI that had changed. This one is evolving differently...opposite evolution.

@psuhoffman

[psuhoffman]

17 minutes ago, 40/70 Benchmark said:

@psuhoffman very good point. Easy to drive yourself crazy, and dillute what is an already paltry sample size of data by endeavoring to assign more specific criteria in binning ENSO events. 

I have always interpreted the data as moderate el nino favoring mid atl most (stronger STJ, more miller a) and weak favoring sne most (More n stream dependent..miller b). Modoki is just better for the east coast in general because the central PAC source of forcing teleconnects to a weaker PAC jet, more PAC ridging and polar blocking. As far as modoki goes, I believe that it is best not to crudely designate or generalize as either modoki or cannonical, but rather utilize a sliding scale akin to that which is utilized to assess intensity/ONI....ie +1.0 modoki value is strongly modoki, +.50 to +1.0 is moderately modoki, and under +.50 minimally modoki hedging towards cannonical. Very few events register as negative, but those that do are also powerful, such as 1982, 1997 and 2015....1976 being the exception, as it was modestly negative and peaked as weak ONI. The catch is that the structure of ENSO is usually relatively fluid, thus assessing and assigning a numeric value at any given, arbitrary point in time is a fool's errand because it provides but a mere snapshot at random point. My aim is to assess this "snapshot" and assign a numerical value to denote its place on the modoki vs cannonical continuum during the apex of its ability to manifest itself into the hemispheric regime and modulate forcing schemes. This is during peak ONI intensity, which will also usually coincide with maximum bimonthly MEI. IOW, if the el Nino peaks during the OND tri monthly period, calculate the mean of those three monthly modiki values to assign a seasonal value.

Remember this...generalizations and meteorology do not mix well, especially within the context of this burgeoning frontier science referred to as seasonal forecasting. Always keep an open mind and be ready for anything. The moment that your throught processes become too rigid, you fail and fail badlt, as I did last season.

Agree with those 2 points completely.  It just gets more complicated wrt parsing exact types of modoki.  Last year there was a pretty heated twitter war over classification between people using the older definition of modoki and some who were using the newer more restrictive one.  It wasnt very productive in terms of advancing anything useful for a forecast.  

[40/70 Benchmark]

3 minutes ago, psuhoffman said:

Agree with those 2 points completely.  It just gets more complicated wrt parsing exact types of modoki.  Last year there was a pretty heated twitter war over classification between people using the older definition of modoki and some who were using the newer more restrictive one.  It wasnt very productive in terms of advancing anything useful for a forecast.  

Yea, I never engage in the debate over whether eastern regions need to be below +.50, or whether the west just needs to be warmer. I let the Japanese do the calculations and plug them in.

[psuhoffman]

14 minutes ago, 40/70 Benchmark said:

@psuhoffman

You're right, I think I was confusing 94/95 and 14/15 wrt how they evolved.  14/15 was somewhat similar to 06/07 in that they started more "classic" nino looking and evolved opposite of most modoki into a central pac based event.  Of course 07 and 15 had such vastly opposite results wrt snowfall that doesn't really help much wrt classification and gleaning meaningful expectations from that.  Of course the SST is the northern PAC region was much more favorable heading into 14/15 than 06/07 and that could have a lot to do with the different results.  

[40/70 Benchmark]

35 minutes ago, psuhoffman said:

You're right, I think I was confusing 94/95 and 14/15 wrt how they evolved.  14/15 was somewhat similar to 06/07 in that they started more "classic" nino looking and evolved opposite of most modoki into a central pac based event.  Of course 07 and 15 had such vastly opposite results wrt snowfall that doesn't really help much wrt classification and gleaning meaningful expectations from that.  Of course the SST is the northern PAC region was much more favorable heading into 14/15 than 06/07 and that could have a lot to do with the different results.  

Fall of 2006 had some toasty region 1.2 readings, though I think that you are right in that both ended up moderately modoki.

[frd]

A possible evolution regarding the PV going forward, seems plausible. I see HM posted on the topic as well. So, generally speaking a strengthening, but hopefully not going crazy. Then after this a weakening again. Well, time will tell. 

Of course after last year's SSWE debacle I would be happy a a simple and favorable elongation of the PV and a general weakening, no need for anything further  than that IMHO.

 

 

And HM's recent post:

 

 

[PrinceFrederickWx]

15 hours ago, WxWatcher007 said:

I don’t recall any kind of torch in Dec 2013, but living in DC proper, winter didn’t start until right after the new year. Those events were not really measurable where I was. Very nice for other areas though.

Boy, what a winter that was. We’d all sign in a heartbeat for a repeat. 

It was a brief torch (December 20-23) but pretty extreme. BWI had daily record highs AND high minimums on both Dec 21-22, along with a monthly high minimum on the 22nd. By Christmas Day, however, we were back to cold. Everyone seems to think that winter was wall-to-wall cold, but it was not.

I'm not even sure if I'd sign up for a repeat of that winter, as that seemed to be more of lucking out on every possible chance and threading every needle in a mediocre pattern. Plus it wasn't that good IMBY compared to most areas.