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January 2021 General Discussions & Observations Thread


Stormlover74
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3 minutes ago, NEG NAO said:

Isn't it suspicious that we go from suppressed to a cutter so fast - and shouldn't that storm cutting through the GL be forced to redevelop along the coast south of us if there was any true blocking go on ?

prateptype_cat.conus.png

Not too worried about the 25th-26th...something should happen.  I am paying attention to this Thu night-Fi.  Doersbt mean it will happen but surprised the GEFS is up a little on qpf. 

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13 minutes ago, NEG NAO said:

Isn't it suspicious that we go from suppressed to a cutter so fast - and shouldn't that storm cutting through the GL be forced to redevelop along the coast south of us if there was any true blocking go on ?

prateptype_cat.conus.png

CMC shows same thing but a little colder. I agree with the block probably looking at a quicker transfer. Even with the CMC look it's 2 to 3 before changover.

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4 hours ago, snowman19 said:

^The other thing we haven’t been able to do in several years is sustain a -EPO

 

You're 100% right about how hard it's been to sustain a -epo around here but BAMwx is awful.  That crew flops around like a fish usually and they're wrong quite often.  

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1 hour ago, MJO812 said:

Nice signal even if its warm for our area this far out.

 

27 minutes ago, NEG NAO said:

Isn't it suspicious that we go from suppressed to a cutter so fast - and shouldn't that storm cutting through the GL be forced to redevelop along the coast south of us if there was any true blocking go on ?

prateptype_cat.conus.png

 

You can't have a storm driving that far north and it not be a warmish solution for most of our sub.  There's strong signal on the ensembles for a storm in that time-frame.  It would likely not be a full blown cutter but if it cuts into Ohio, redevelopment may happen too far north which would favor our nw burbs and even more likely New England. 

 

There's still a ton of time to figure out any details.   Good thing this is a weather forum so we can weenie out a bit at a day 10 storm. 

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2 hours ago, wdrag said:

I like the conversation and my only thought with the 26th,  watch the 22nd.  For those who wish NIL for the 22nd.. root for the 12z/16 GEFS to back off a bit on qpf and for UKMET to not have developed some sort of short wave in the Ohio Valley to join with the northern tier ese driver.  We'll have to count on this being one of the UKMET'S spurious wrong off by 300 miles on  qpf axis operational cycles.  It does this kind of thing...am saving the UK for qpf for 12/22 night/23 AM for a future compare. 

I'll be away from the computer for awhile after 1P. 

Good catch regarding the 22nd.  The 12z GEFS were noticeably wetter, particularly into the Ohio Valley, than any recent runs. I'd like to see the individuals - there must be a few with a much stronger s/w and maybe some northern stream phasing. The mean even clips southern NJ with the 0.1" contour. The mean is in stark contrast to the operational GFS, ECM, and CMC runs, which completely squash the wave and its associated precipitation. If there is really some room here for a more northward solution (which the 12z GEFS questionably suggest), I'd like to see the GEFS hold strong for a few runs and then eventually the operationals show some movement.  Right now they are steadfast in their suppressed look. Otherwise we are stuck always looking deep into the future.

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The ICON and NAVGEM also show precipitation making it into our area around the 22nd. Both also seem to have trended a little north. I don't know if the NAVGEM has any value for mid-range forecasting in our region, and I've been a little disappointed with the ICON this year particularly beyond 72hrs. But both models do show a less suppressive flow regime than the EC, GFS, CMC trio for late next week.

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Have no additional contributions on the 22nd.  the 25th-26th yes.  Notoriously,  Modeling doesn't handle ejection of the sw USA 500MB closed lows very well. Impact differences are huge in the eastern USA.  Think I want to wait 3 more days (19th before getting my hopes too high). 

 

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The storm responsible for the most recent rainfall continues to pull away from the region. Storm total rainfall amounts included:

Allentown: 0.56"
Boston: 1.03"
Bridgeport: 0.72"
Islip: 0.82"
New York City: 1.16"
Newark: 1.23"
Philadelphia: 0.23"
Providence: 1.33"

Tomorrow will be partly sunny and somewhat cooler. However, additional potential for storms exists through at least the next two weeks.

During the second half of January, there will be some potential for snow events in the Middle Atlantic and southern New England regions, even as the forecast AO-/PNA- pattern is typically not a very snowy one. There continues to be ensemble support for a possible snow event in the region during the January 21-23 timeframe. Another timeframe highlighted by the ensembles is January 25-28. The latter period may have greater potential.

AO-/PNA- patterns are typically not snowy. The frequency of measurable snowfall is just over 90% of climatology in Boston and Philadelphia and around 80% of climatology in New York City for the January 21-31, 1950-2020 period. The frequency of 2" or more daily snowfall was just above 90% of climatology for Philadelphia, but fell sharply to 50% of climatology in New York City and 65% of climatology in Boston. For daily snowfall amounts in excess of 2", the frequency fell sharply for Philadelphia. As a result, such patterns typically have produced significant snowstorms (6" or above snowfall) in the northern Middle Atlantic and southern New England regions during late January. The biggest snowfalls during an AO-/PNA- pattern during the January 20-31, 1950-2020 period were as follows: Boston: 7.3", January 21, 2011; New York City: 4.2", January 21, 2011; and, Philadelphia: 3.0", January 20, 2000.

Neither event is a certainty at this point in time. Afterward, the evolution of the AO will determine whether potential for measurable snow events will continue into February.

The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -1.1°C for the week centered around December 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.77°C and the ENSO Region 3.4 anomaly has averaged -1.07°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +20.26 today.

Today, the preliminary Arctic Oscillation (AO) figure was -2.042.

On January 15 the MJO was in Phase 4 at an amplitude of 1.140 (RMM). The January 14-adjusted amplitude was 1.222.

Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. The mean zonal winds have reversed at 1 mb and 10 mb. They have all but died at 30 mb and might still reverse for a brief period. In the wake of this warming event, the polar vortex will split with the dominant piece will, as is typical for vortex-splitting events, migrate to Eurasia.

The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Blocking appears likely to continue into at least the last week of January.

Based on sensitivity analysis applied to the latest guidance, there is an implied 80% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.2°.

 

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22 minutes ago, Rjay said:

I'm usually not the type to say this but there's no way that's happening like that.   The prinary is not making it into Ontario. 

The v16 runs 3 systems through the Lakes over the next 10 days. The northern stream storm track looks to be positioned through southern Canada, so I don't see any reason why it couldn't play out like that. If the model shows a low pressure center in southern Ontario around the 26th, I think we should assume that it could happen. After all, the model physics is built to conform to the boundaries of what is physically possible.

It's completely valid to bet or argue against what the v16 is showing. If it's an outlier, we can point to that. But I don't think we can rule out certain outcomes because of our superior understanding of atmospheric physics. I think that is basically just guessing.

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13 minutes ago, eduggs said:

The v16 runs 3 systems through the Lakes over the next 10 days. The northern stream storm track looks to be positioned through southern Canada, so I don't see any reason why it couldn't play out like that. If the model shows a low pressure center in southern Ontario around the 26th, I think we should assume that it could happen. After all, the model physics is built to conform to the boundaries of what is physically possible.

It's completely valid to bet or argue against what the v16 is showing. If it's an outlier, we can point to that. But I don't think we can rule out certain outcomes because of our superior understanding of atmospheric physics. I think that is basically just guessing.

EURO is the superior Atmospheric Physics model - going with the EURO all the way and most of the other models will trend towards it as has happened many times in the past - That 18Z run of the GFSv16 shows a primary low plowing right through a block - not likely IMO........

What is the best weather forecast model? | The Weather Guys (wisc.edu)

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2 hours ago, Rjay said:

I'm usually not the type to say this but there's no way that's happening like that.   The primary is not making it into Ontario. 

 

2 hours ago, eduggs said:

The v16 runs 3 systems through the Lakes over the next 10 days. The northern stream storm track looks to be positioned through southern Canada, so I don't see any reason why it couldn't play out like that. If the model shows a low pressure center in southern Ontario around the 26th, I think we should assume that it could happen. After all, the model physics is built to conform to the boundaries of what is physically possible.

It's completely valid to bet or argue against what the v16 is showing. If it's an outlier, we can point to that. But I don't think we can rule out certain outcomes because of our superior understanding of atmospheric physics. I think that is basically just guessing.

 

1 hour ago, NEG NAO said:

EURO is the superior Atmospheric Physics model - going with the EURO all the way and most of the other models will trend towards it as has happened many times in the past - That 18Z run of the GFSv16 shows a primary low plowing right through a block - not likely IMO........

What is the best weather forecast model? | The Weather Guys (wisc.edu)

To be fair I didn't really look into the details until now.  The low in Canada is just a vigorous northern stream s/w.  It's not like a storm developed over the plains and drove into the block.  So I guess it's plausible. 

0b0b1bb4-b305-4e7f-9064-44056492cbb9.thumb.gif.7b199cbdfe831b188fd457f5b4601e7e.gif 

To put it simply, the gfs op has a strong southern stream s/w and weaker northern stream which allows heights to rise and the storm comes up the coast.  Note the higher heights on the EC than the para.  

gfs_z500a_us_40.thumb.png.e08cb1b85435f8396c835cf3d923e320.png

 

 The para has a weaker, slower southern stream s/w and a stronger northern stream keeping heights on the EC much lower.  Even if the southern stream were stronger this run it wouldn't come up the coast.

gfsp_z500a_us_40.thumb.png.d2bf1dabd0a6cfa22074b2f57dee68f0.png

 

Btw, I'm legit laughing at breaking down a day 9/10 op run but it's always fun to learn I guess.  

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7 minutes ago, Rjay said:

 

 

 

To be fair I didn't really look into the details until now.  The low in Canada is just a vigorous northern stream s/w.  It's not like a storm developed over the plains and drove into the block.  So I guess it's plausible. 

0b0b1bb4-b305-4e7f-9064-44056492cbb9.thumb.gif.7b199cbdfe831b188fd457f5b4601e7e.gif 

To put it simply, the gfs op has a strong southern stream s/w and weaker northern stream which allows the storm come up the coast.  Note the higher heights on the EC than the para.  

gfs_z500a_us_40.thumb.png.e08cb1b85435f8396c835cf3d923e320.png

 

 The para has a weaker, slower southern stream s/w and a stronger northern stream keeping heights on the EC much lower.  Even if the southern stream were stronger this run it wouldn't come up the coast.

gfsp_z500a_us_40.thumb.png.d2bf1dabd0a6cfa22074b2f57dee68f0.png

 

Btw, I'm legit laughing at breaking down a day 9/10 op run but it's always fun to learn I guess.  


well I don’t ever look at the gfs or gfs para, or any other guidance.

 

but if I did I would say this is a fine comparison young man, the finest.

 

do you buy the stronger northern stream? Do you think there’s time to toss in a tilt in the right place and force it up? 
 

 

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Just now, Njweathered said:


well I don’t ever look at the gfs or gfs para, or any other guidance.

 

but if I did I would say this is a fine comparison young man, the finest.

 

do you buy the stronger northern stream? Do you think there’s time to toss in a tilt in the right place and force it up? 
 

 

I don't think either are close to the final solution.   I was just trying to explain why I was wrong saying the para solution couldn't happen.  

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20 minutes ago, Njweathered said:


well I don’t ever look at the gfs or gfs para, or any other guidance.

 

but if I did I would say this is a fine comparison young man, the finest.

 

do you buy the stronger northern stream? Do you think there’s time to toss in a tilt in the right place and force it up? 
 

 

No way this cuts! “Block to strong, no cut!”

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