• Member Statistics

    16,114
    Total Members
    7,904
    Most Online
    PJAshtabulaCo
    Newest Member
    PJAshtabulaCo
    Joined
CAPE

Winter 2020-21 Discussion

Recommended Posts

30 minutes ago, RIC_WX said:

The difference is entirely in the NAO.  In 95/96, we had alternating periods of cold/snow and otherwise mild and sunny wx, it was the winter that had something for everyone.  I believe it's remembered as cold because winter showed up early and hung around into April in addition to all the snow - but in the means it wasn't really cold, and plenty of very mild days.  The blocking slowed the overall pattern progression enough to extend the cold intrusions and pull the storm track into the ideal location for us repeatedly - shift the SE ridge 500 miles southeast and watch what happens.

Hard to argue we are seeing a much different setup this year, but absent any sustained blocking the cold is in and out in 36 hours, the SE ridge is back over our heads instead of off the coast, the storm track is west of the mountains.  Unless you can explain what will break the persistence of the past several winters to deliver more than transient periods of bootleg blocking we are getting a very similar pattern we would have seen in 95/96 if the block hadn't been present.

IMO this winter is going to come down to the AO/NAO, if they are predominately positive this winter, everyone south of New England (really central New England) is screwed. Just -NAO without -AO isn’t going to help IMO, they both need to be predominantly negative together to get a good winter this time.  This La Niña is basin-wide and is very likely peaking strong, it’s also very strongly coupled. I don’t think we are going to see a good PAC side, it’s probably going to be garbage. Griteater pointed this out, but the pressure anomalies in the North Pacific, GOA and Alaska so far this month and projected going into November are now suggesting a flat Aleutian ridge as opposed to the +QBO Ninas that had poleward ones. If the AO/NAO cooperate, then it’s game on for cold and snow, see 73-74 super Niña, 10-11, 95-96 

 

Share this post


Link to post
Share on other sites
54 minutes ago, snowman19 said:

IMO this winter is going to come down to the AO/NAO,

 

This is basically every winter for us regardless of Enso state though. Our area simply does not do well without some blocking. 

  • Like 2

Share this post


Link to post
Share on other sites
2 minutes ago, clskinsfan said:

This is basically every winter for us regardless of Enso state though. Our area simply does not do well without some blocking. 

We generally need some HL 'help' to get average or above average snow. In the absence of a -AO/NAO, a -EPO can get it done.

Share this post


Link to post
Share on other sites
3 minutes ago, CAPE said:

We generally need some HL 'help' to get average or above average snow. In the absence of a -AO/NAO, a -EPO can get it done.

Someone last year wrote a post (Maybe PSU but I cant remember) about the statistics and importance of a -NAO for our snows. The overwhelming majority of our snows seemed to occur with a -NAO even if it is only transient. 

Share this post


Link to post
Share on other sites
26 minutes ago, clskinsfan said:

Someone last year wrote a post (Maybe PSU but I cant remember) about the statistics and importance of a -NAO for our snows. The overwhelming majority of our snows seemed to occur with a -NAO even if it is only transient. 

I posted a chart of the state of the major indices before all of the Baltimore/Washington areas warning snowfalls going back to 1948. Its in the snow climo study thread. As @CAPE said we need some HL help. An east based poleward EPO ridge can compensate for a bad NAO. The AO is tricky because there is overlap from both the EPO and NAO so you get some cross contamination when you simply use that index. But taken holistically it’s evident we need some help up top somewhere.   We’re simply too far south if you get a contracted polar jet and zonal pattern. We need buckling somewhere. 
 

Specific to a La Niña the NAO becomes even more important. Baltimore rarely gets any snow of significance in a Nina without NAO help. I’ve not run the numbers but it’s likely similar for most of the region. It’s makes sense..in a Nina the pacific ridge is likely to be too far west to get er done all by itself. Add in a lack of STJ and fast NS jet and it makes sense that without the NAO buckling the flow in our favor we would be SOL. 

  • Like 1

Share this post


Link to post
Share on other sites
3 minutes ago, psuhoffman said:

I posted a chart of the state of the major indices before all of the Baltimore/Washington areas warning snowfalls going back to 1948. Its in the snow climo study thread. As @CAPE said we need some HL help. An east based poleward EPO ridge can compensate for a bad NAO. The AO is tricky because there is overlap from both the EPO and NAO so you get some cross contamination when you simply use that index. But taken holistically it’s evident we need some help up top somewhere.   We’re simply too far south if you get a contracted polar jet and zonal pattern. We need buckling somewhere. 
 

Specific to a La Niña the NAO becomes even more important. Baltimore rarely gets any snow of significance in a Nina without NAO help. I’ve not run the numbers but it’s likely similar for most of the region. It’s makes sense..in a Nina the pacific ridge is likely to be too far west to get er done all by itself. Add in a lack of STJ and fast NS jet and it makes sense that without the NAO buckling the flow in our favor we would be SOL. 

I thought it was you. Thanks PSU. And I am glad to be back for the winter. Is Bob back yet?

Share this post


Link to post
Share on other sites
5 minutes ago, psuhoffman said:

I posted a chart of the state of the major indices before all of the Baltimore/Washington areas warning snowfalls going back to 1948. Its in the snow climo study thread. As @CAPE said we need some HL help. An east based poleward EPO ridge can compensate for a bad NAO. The AO is tricky because there is overlap from both the EPO and NAO so you get some cross contamination when you simply use that index. But taken holistically it’s evident we need some help up top somewhere.   We’re simply too far south if you get a contracted polar jet and zonal pattern. We need buckling somewhere. 
 

Specific to a La Niña the NAO becomes even more important. Baltimore rarely gets any snow of significance in a Nina without NAO help. I’ve not run the numbers but it’s likely similar for most of the region. It’s makes sense..in a Nina the pacific ridge is likely to be too far west to get er done all by itself. Add in a lack of STJ and fast NS jet and it makes sense that without the NAO buckling the flow in our favor we would be SOL. 

If you look back at La Nina winters in the NYC metro area, they are also screwed without AO/NAO assist. All the good La Niña winters were predominantly negative AO/NAO, the bad ones were predominantly positive AO/NAO

Share this post


Link to post
Share on other sites

With regard to the AO and Nina winters, there have been 41 -AO winters since 1950-51. Among those 41, 11 occurred during La Nina years, 14 occurred during El Nino, and 16 in ENSO-neutral. By percentage, this comes out to, 52.3% of La Nina years (11/21), 53.8% of El Nino years (14/26), and 69.5% (16/23) ENSO-neutral winters. 

Among those 21 La Nina years at DCA, the average snowfall is 12.0", below the 1981-2010 average of 15.4". In +AO years, the average is just 8.8" with only one season (1971-1972) finishing above average (1999-2000 was exactly average). In -AO Nina years, the average is 14.4", however only 3 out of 11 featured above average snowfall. If you remove the massive outlier of 1995-96, the average falls to just 11.2".

For BWI, those numbers don't get much better. In fact, they arguably paint a bleaker picture. Among those 21 La Nina years at BWI, the average snowfall is 16.0", below the 1981-2010 average of 20.1". In +AO years, the average is just 12.1" with only one season (1999-2000) finishing above average. In -AO Nina years, the average is 18.9", however only 1 out of 11 featured above average snowfall and it's, you guessed it, 1995-96. If you remove the massive outlier of 1995-96, the average falls to just 14.5". 

If you break it down by month, in Nina winters at DCA, 4/21 Decembers have seen above average snowfall (3/4 in -AO years), 7/21 Januarys (4/7 in -AO years), and 4/21 Februarys (2/4 in -AO years). At BWI, it's 7/21 Decembers (5/7 in -AO years), 8/21 Januarys (5/8 in -AO years), and 5/21 Februarys (4/5 in -AO years).

Long story short, historically speaking, La Ninas are no bueno for the Mid-Atlantic, which should not come as a surprise. Clearly Atlantic blocking helps, as PSU outlined, but still an uphill battle from there. I'd be interested to see how the Pacific numbers shake up too - I imagine the +AO years had at least a semblance of +PNA/-EPO/-WPO. 

  • Like 5
  • Thanks 2

Share this post


Link to post
Share on other sites

@Winter Wizard

what sticks out for our area is when you look at each snowfall event you find that even the ones in a +AO/NAO Nina came during a period of blocking within the +AO. 2000 was a good example. All the snow came during a 10 day period with blocking. The rest of the winter was virtually snowless. 

  • Thanks 1

Share this post


Link to post
Share on other sites
1 hour ago, Scraff said:

In DT we trust. :weenie:

DT lol Has he gotten a winter forecast right in the last 4 years? I lost all respect for him when I saw him wish cancer on someone who disagreed with him a few years back

  • Like 1

Share this post


Link to post
Share on other sites

Read on Twitter earlier that Henry Margusity is supposedly hyping on his paid site that there’s a classic tripole in the Atlantic SSTs that will lead to a -NAO winter....if true, not sure what he’s looking at, but we have anything but a classic tripole right now: 

VS what we have:  cdas-sflux_ssta_atl_1.png

Share this post


Link to post
Share on other sites
27 minutes ago, snowman19 said:

Read on Twitter earlier that Henry Margusity is supposedly hyping on his paid site that there’s a classic tripole in the Atlantic SSTs that will lead to a -NAO winter....if true, not sure what he’s looking at, but we have anything but a classic tripole right now: 

VS what we have:  cdas-sflux_ssta_atl_1.png

Why do people continue to commit intellecutal suicide by reading Henry?

  • Like 2

Share this post


Link to post
Share on other sites
5 hours ago, snowman19 said:

DT lol Has he gotten a winter forecast right in the last 4 years? I lost all respect for him when I saw him wish cancer on someone who disagreed with him a few years back

To be fair, I think most have done poorly the past couple of years. I know raindance and Tom hit last year.....about it.

But NOONE forecasted the level of atrocity that unfolded throughout January and February of 2020.

  • Like 2

Share this post


Link to post
Share on other sites
On 10/23/2020 at 1:19 PM, psuhoffman said:

@Winter Wizard

what sticks out for our area is when you look at each snowfall event you find that even the ones in a +AO/NAO Nina came during a period of blocking within the +AO. 2000 was a good example. All the snow came during a 10 day period with blocking. The rest of the winter was virtually snowless. 

I could see something like that this season. I really like 2000 as an analog, too....prob +3 on my big three list.

Share this post


Link to post
Share on other sites
1 hour ago, 40/70 Benchmark said:

Could anyone in here post the UK and CFS forecast for la nina? I have only been able to find the plumes...I'm looking for the SST anomaly maps.

Thanks.

I’m looking now....I know it was said that both models are forecasting a strong La Niña, if I find it, I’ll give you the links right away 

Share this post


Link to post
Share on other sites
2 hours ago, 40/70 Benchmark said:

I could see something like that this season. I really like 2000 as an analog, too....prob +3 on my big three list.

I see the similarities. And while 2000 was one of the best snowfall Nina’s in our area I also think expecting a repeat of that 2 week stretch in January is risky. We torched with no chance at snow the entire rest of that winter.  What if that short period of blocking didn’t happen. Or what if we simply didn’t get lucky and nothing came of it. I tend to think of the outcome that season as more lucky than good. A repeat could end up a disaster. Please convince me otherwise though. I could use some optimism. 

Share this post


Link to post
Share on other sites
13 minutes ago, psuhoffman said:

I see the similarities. And while 2000 was one of the best snowfall Nina’s in our area I also think expecting a repeat of that 2 week stretch in January is risky. We torched with no chance at snow the entire rest of that winter.  What if that short period of blocking didn’t happen. Or what if we simply didn’t get lucky and nothing came of it. I tend to think of the outcome that season as more lucky than good. A repeat could end up a disaster. Please convince me otherwise though. I could use some optimism. 

Err....2020 chaos leading to us fluking into something? :D But seriously though, do we have much other choice but to hope for fluke(s) in a nina?

Share this post


Link to post
Share on other sites
12 hours ago, Maestrobjwa said:

Err....2020 chaos leading to us fluking into something? :D But seriously though, do we have much other choice but to hope for fluke(s) in a nina?

Getting it to snow here is fluky most winters. It's probably become more so recently.

  • Like 1

Share this post


Link to post
Share on other sites
On 10/23/2020 at 9:26 AM, RIC_WX said:

The difference is entirely in the NAO.  In 95/96, we had alternating periods of cold/snow and otherwise mild and sunny wx, it was the winter that had something for everyone.  I believe it's remembered as cold because winter showed up early and hung around into April in addition to all the snow - but in the means it wasn't really cold, and plenty of very mild days.  The blocking slowed the overall pattern progression enough to extend the cold intrusions and pull the storm track into the ideal location for us repeatedly - shift the SE ridge 500 miles southeast and watch what happens.

Hard to argue we are seeing a much different setup this year, but absent any sustained blocking the cold is in and out in 36 hours, the SE ridge is back over our heads instead of off the coast, the storm track is west of the mountains.  Unless you can explain what will break the persistence of the past several winters to deliver more than transient periods of bootleg blocking we are getting a very similar pattern we would have seen in 95/96 if the block hadn't been present.

All of the big winters are like that though- even 13/14 and 09/10, both of which had long stretches of warm, snowless in between storms. We never do sustained cold and snowcover in this region so the question to me is more about why in the big years does everything seem to line up at just exactly the correct times over and over.

Share this post


Link to post
Share on other sites
22 hours ago, 40/70 Benchmark said:

I could see something like that this season. I really like 2000 as an analog, too....prob +3 on my big three list.

One of my favorite winters in Philly. If you’re talking about 00-01. It had an event pretty much every month. Just an exciting winter with the NAO in late December. Dec 30 still the first legit snowstorm I stayed up all night on wxforums. I remember speaking to Ji at like 2 in the AM he was depressed since the skies were clear with a winter storm warning lol. 

  • Weenie 1

Share this post


Link to post
Share on other sites
4 minutes ago, PrinceFrederickWx said:

All of the big winters are like that though- even 13/14 and 09/10, both of which had long stretches of warm, snowless in between storms. We never do sustained cold and snowcover in this region so the question to me is more about why in the big years does everything seem to line up at just exactly the correct times over and over.

We always talk about the importance of HL blocking, but many times it is not sustained. In 2009-10 it was pretty much wall to wall, legit -AO/NAO for the entire winter (see my display pic). That sets us up so we don't have to thread the needle. Ofc it was also a Modoki Nino. We get that combo and its hard not to see a few big winter storms.

Share this post


Link to post
Share on other sites
18 minutes ago, PrinceFrederickWx said:

All of the big winters are like that though- even 13/14 and 09/10, both of which had long stretches of warm, snowless in between storms. We never do sustained cold and snowcover in this region so the question to me is more about why in the big years does everything seem to line up at just exactly the correct times over and over.

It just seems we’ll never know the exact answer to that because there are just too many factors. Not only dealing with meteorological, but we have constant changing climate issues as well. 

Share this post


Link to post
Share on other sites

Hard to beat the December 2009 storm for me. December is mostly a Fall month around here, and we rarely see a KU event before Xmas.

  • Like 1

Share this post


Link to post
Share on other sites
8 minutes ago, CAPE said:

Hard to beat the December 2009 storm for me. December is mostly a Fall month around here, and we rarely see a KU event before Xmas.

Cold powder with no mixing worries along/east of 95 with any storm in winter is a blessing, especially pre-Christmas.

  • Like 2

Share this post


Link to post
Share on other sites
1 minute ago, nj2va said:

Cold powder with no mixing worries along/east of 95 with any storm in winter is a blessing, especially pre-Christmas.

Yup. It was rare and perfect. Sure it was a slushy, foggy mess by Xmas day and it rained, but that's how we roll here.

 

  • Like 2

Share this post


Link to post
Share on other sites
1 hour ago, Wentzadelphia said:

One of my favorite winters in Philly. If you’re talking about 00-01. It had an event pretty much every month. Just an exciting winter with the NAO in late December. Dec 30 still the first legit snowstorm I stayed up all night on wxforums. I remember speaking to Ji at like 2 in the AM he was depressed since the skies were clear with a winter storm warning lol. 

No. 1999-2000.

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.