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Winter 2018-19 Is Coming


WxUSAF

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I’m sure others can give a better description of the weeklies but here is mine...
The current pattern relaxes with the trough pulling west through mid November and then as we head not December the aleutian low gets cranking again. Nice big -epo with some higher heights into the AO region but....a raging +nao.
Personally, I’ll take what it’s showing...hopefully the NAO evolves and works with us as December wears on.

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3 hours ago, BTRWx's Thanks Giving said:

Very good outlook and "spot on" with what we should expect. Looks like it will be a good winter for both our regions. 

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This weekend is looking VERY interesting in the Mid Atlantic.

There are going to be many many coastal lows this low sun season. You all are going to get sick and tired of coastal lows by New Years.

This time around, the mountains may see some wet snow, and I think the highest elevations will see several inches. If you want to see some early snow, hit up western Rt 7 and all of Rt 9 on Saturday and Saturday Night. Paeonian Springs on Rt 9 will see their first snows of the new season.

Washington DC will see a white Thanksgiving and also a very white Christmas. Snow weenies all over the Mid Atlantic Region will be in permanent orbit by New Years. Snow accumulation records will be set then rebroken throughout the Epic Winter of 2018-2019, even in Washington DC.

All of the science you need to know in the Mid Atlantic this winter, is that I am living in south central Texas and THAT TRANSLATES TO RECORD SNOWS this winter in the entire Mid Atlantic Region. The Modoki Nino is already a given. Lots of -NAO and -AO are givens. But I, Jebman, am now in Buda Texas and THAT is why you all in the Mid Atlantic will see record amounts of snow this winter. Thats all the meteorological science you'll ever need to know, lol. You are all going to get buried alive by coastal blizzard after coastal blizzard after coastal blizzard after coastal blizzard. You are gonna need a MUCH bigger shovel! You think 2009-10 was something, think again.

You can all take that straight to the bank, with 25 percent interest.

One last point. The Atlantic Meridional Overturning Circulation, or AMOC, is slowing down a lot.

All HELL is gonna break loose this winter.

 

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Random notes From a talk by Amy Butler of NOAA

 Impacts of SSW extend to 60 days in the troposphere ... with the biggest impacts downstream of North American jet ... cold anomalies midlatitudes/Switzerland  ... warm anomalies eastern Canada, sub-tropics 

Downward coupling does not occur after all SSW ... and that SSW occur in context of other forcings such as ENSO, MJO Phase ..

SSW forecasts exceeding 15 days have no skill 

Week 3/4 skill is much larger when models are initialized with a weak polar vortex.  

Stronger more organized MJO when the 50 hPA QBP index is easterly 

 

 

 

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2 hours ago, dallen7908 said:

 

Random notes From a talk by Amy Butler of NOAA

 Impacts of SSW extend to 60 days in the troposphere ... with the biggest impacts downstream of North American jet ... cold anomalies midlatitudes/Switzerland  ... warm anomalies eastern Canada, sub-tropics 

Downward coupling does not occur after all SSW ... and that SSW occur in context of other forcings such as ENSO, MJO Phase ..

SSW forecasts exceeding 15 days have no skill 

Week 3/4 skill is much larger when models are initialized with a weak polar vortex.  

Stronger more organized MJO when the 50 hPA QBP index is easterly 

 

 

 

That is true SSW forecasts exceeding 15 or more days have basically zero skill. 

However certain patterns, features,  triggers and other factors can set up and may provide the foundation for a PV displacement or even a SSW event.  

Last year, as you know,  there was a significant SSWE,  but the models did not forecast exactly the time when it occured,  but it did happen and they signaled the potential of one.

 

http://www.atmos.albany.edu/student/hattard/plots/mapdisco/9Feb_2018/zonal_wind_forecasts.php

 

 

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42 minutes ago, frd said:

Last year, as you know,  there was a significant SSWE,  but the models did not forecast exactly the time when it occured,  but it did happen and they signaled the potential of one.

Alexey Karpechko gave a talk on SSW predictability.  He found that last year's event was hinted at 12-13 days out, predicted by 30% of ensembles 11 days out, predicted by 100% of ensembles 4 days out. 

Here is the abstract from a recent paper by him. 

 

The skill of the Arctic stratospheric retrospective ensemble forecasts (hindcasts) of the European Centre for Medium-Range Weather Forecasts extended-range system is analyzed with a focus on the predictability of the major sudden stratospheric warmings (SSWs) during the period 1993–2016. Thirteen SSWs took place during this period. It is found that forecasts initialized 10–15 days before the SSWs show worse skill in the stratosphere than forecasts initialized during normal conditions in terms of root-mean-square errors but not in terms of anomaly correlation. Using the spread of ensemble members to estimate forecasted SSW probability, it is shown that some SSWs can be predicted with high (>0.9) probability at lead times of 12–13 days if a difference of 3 days between actual and forecasted SSW is allowed. Focusing on SSWs with significant impacts on the tropospheric circulation, on average, the forecasted SSW probability is found to increase from nearly 0 at 1-month lead time to 0.3 at day 13 before SSW, and then rapidly increases to nearly 1 at day 7. The period between days 8 and 12 is when most of the SSWs are predicted, with a probability of 0.5–0.9, which is considerably larger than the observed SSW occurrence frequency. Therefore, this period can be thought of as an estimate of the SSW predictability limit in this system. Indications that the predictability limit for some SSWs may be longer than 2 weeks are also found; however, this result is inconclusive and more studies are needed to understand when and why such long predictability is possible.

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11 minutes ago, BTRWx's Thanks Giving said:

This is way out there, but here's the first sign of November possibly heating up! ecmwf-ens_T850a_us_10.png

Looking at the trends in the guideance the last few days, even the last week of October is shaping up not to be as cold as was originally forecasted a week ago.  

I think the cold shifts West in November and although not extreme we go  back to a AN temp pattern.  

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Just now, frd said:

Looking at the trends in the guideance the last few days, even the last week of October is shaping up not to be as cold as was originally forecasted a week ago.  

I think the cold shifts West in November and although not extreme we go  back to a AN temp pattern.  

Exactly what we need for djf!

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10 hours ago, dallen7908 said:

 

Random notes From a talk by Amy Butler of NOAA

 Impacts of SSW extend to 60 days in the troposphere ... with the biggest impacts downstream of North American jet ... cold anomalies midlatitudes/Switzerland  ... warm anomalies eastern Canada, sub-tropics 

Downward coupling does not occur after all SSW ... and that SSW occur in context of other forcings such as ENSO, MJO Phase ..

SSW forecasts exceeding 15 days have no skill 

Week 3/4 skill is much larger when models are initialized with a weak polar vortex.  

Stronger more organized MJO when the 50 hPA QBP index is easterly 

Totally agree with Amy.

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6 hours ago, Maestrobjwa said:

Wait--the 68-69 Niño only had 9.1"? Wonder what happened that year, lol

Bad luck. Lots of coastal storms. Some turned to rain in DC. Some stayed east. Some miller b jumpers. It was a great winter just to our northeast. Up here it was pretty good too. D.C. Just got unlucky imo. It can happen. 

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17 minutes ago, psuhoffman said:

Bad luck. Lots of coastal storms. Some turned to rain in DC. Some stayed east. Some miller b jumpers. It was a great winter just to our northeast. Up here it was pretty good too. D.C. Just got unlucky imo. It can happen. 

Yuck...well hey, after all the snow that fell in the 60s...that probably made that snow failure easier tolerate, lol But but overall...that's an aberration in a weak-to-moderate Niño, isn't it? (Has that happened any other time in recent decades?)

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Pacific SSTA loop for October so far. Npac is trying to slowly transition to a +PDO. Cool the western region off the coast of Japan eastward to the Aleutians through December and it would actually become near perfect. Eastern NPac is great like it is. Nino region chugging along nicely. 

 

UFsET3u.gif

 

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7 minutes ago, WxUSAF said:

Two months and 20F colder from now and today would be super exciting. High cirrus thickening up, light wind, and a big old storm brewing.

YES!! Oh so close!!! Haven't seen this in the cold months since what...the one-hit blizzard of 2016? Lol It Atmospheric memory exists....I hope it doesn't forget this! Haha

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Here's my stab in the dark ...

December will feature some colder than average periods and a good chance for perhaps one decent snowfall event, that most likely around Dec 20-22. 

January will torch for the first half, record highs are possible. Then it will turn much colder in stages. There may be a second decent snowfall event in late January.

February will retain the late January cold briefly then turn warmer rather steadily, becoming much above normal late in the month.

March will continue this very warm trend. 

Overall then a mildish winter with some brief but possibly tolerable winter spells, snowfall near normal generally despite some of the better intervals (climatology) being too warm. 

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10 minutes ago, Roger Smith said:

Here's my stab in the dark ...

December will feature some colder than average periods and a good chance for perhaps one decent snowfall event, that most likely around Dec 20-22. 

January will torch for the first half, record highs are possible. Then it will turn much colder in stages. There may be a second decent snowfall event in late January.

February will retain the late January cold briefly then turn warmer rather steadily, becoming much above normal late in the month.

March will continue this very warm trend. 

Overall then a mildish winter with some brief but possibly tolerable winter spells, snowfall near normal generally despite some of the better intervals (climatology) being too warm. 

What was your methodology?

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1 hour ago, WxUSAF said:

Two months and 20F colder from now and today would be super exciting. High cirrus thickening up, light wind, and a big old storm brewing.

I forget which meteorologist it was last night... but it was the 11pm news on either channel 4 or 9... and he said if this were winter time we would be talking about 10-15 inches of snow on the way for our region

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