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December 2022 Medium-Long Range Disco


WxUSAF
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1 hour ago, psuhoffman said:

I remember all the hits too, unfortunately that’s a much smaller list. 
 

I’m lucky to have a good memory. Secret is I never studied and I’m not that smart…I just remember everything.  I do think there is value in knowing how we’ve failed though.  

I can’t remember a damn thing, but I’m pretty f’ing smart.

I think.

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This pattern definitely looks favorable, but how does it compare to the biggest Decembers around here?

Below is a plot of the mean snow-to-date climatologically in December from 1980-2021, along with the mean snow-to-date from the top 25% and bottom 25% Decembers snowfall-wise here in DC.Image

Out of those top 25 Decembers snowfall-wise, here are the H5 anomalies plotted on the Northern Hemisphere for each of them.Image

The key similarities to our upcoming pattern and the top 25% Decembers' average pattern around here are troughing near Hawaii/the Aleutians, a cutoff ridge north of AK and ridge bridging in the Arctic (-EPO/-AO/-NAO) and the elephant in the room -- lower heights over the EC.

Below is a composite plot of the 250mb plots in these same years (do note that they are smoothed out since they're for the entire month, but you can still make out two key features):This plot is not dissimilar to the PNA

The two key features here are an active STJ and what seems to be a Pacific jet extension, which promotes a +PNA if I remember correctly.

Our upcoming pattern seems to have an active STJ and a jet extension too, which is why we are expected to see a +PNA of some sorts during this pattern.
Overall, our pattern has key similarities to some other patterns of conducive Decembers, snowfall-wise.

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55 minutes ago, psuhoffman said:

I was up in PA that one winter and got 14” but where I am now got 23” according to the coop down the street. 

That's right! I recorded 24 for the 2 part event. 16 inches with the heavy snow overnight into the morning. Then 1st part ended as some drizzle/ mist. Part 2 was very heavy snow for several hours that evening resulting in 8 more inches. Pretty sure this area bulleyed part 2. If I remember correctly losetoa6 got roughly only 4 inches compared to the 8 here. Sharp cutoff just west of Westminster and just east of the Baltimore/ Carroll county line.

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15 minutes ago, AtlanticWx said:

This pattern definitely looks favorable, but how does it compare to the biggest Decembers around here?

Below is a plot of the mean snow-to-date climatologically in December from 1980-2021, along with the mean snow-to-date from the top 25% and bottom 25% Decembers snowfall-wise here in DC.Image

Out of those top 25 Decembers snowfall-wise, here are the H5 anomalies plotted on the Northern Hemisphere for each of them.Image

The key similarities to our upcoming pattern and the top 25% Decembers' average pattern around here are troughing near Hawaii/the Aleutians, a cutoff ridge north of AK and ridge bridging in the Arctic (-EPO/-AO/-NAO) and the elephant in the room -- lower heights over the EC.

Below is a composite plot of the 250mb plots in these same years (do note that they are smoothed out since they're for the entire month, but you can still make out two key features):This plot is not dissimilar to the PNA

The two key features here are an active STJ and what seems to be a Pacific jet extension, which promotes a +PNA if I remember correctly.

Our upcoming pattern seems to have an active STJ and a jet extension too, which is why we are expected to see a +PNA of some sorts during this pattern.
Overall, our pattern has key similarities to some other patterns of conducive Decembers, snowfall-wise.

Fantastic post. Also easy for dummies like me to comprehend. 

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That's right! I recorded 24 for the 2 part event. 16 inches with the heavy snow overnight into the morning. Then 1st part ended as some drizzle/ mist. Part 2 was very heavy snow for several hours that evening resulting in 8 more inches. Pretty sure this area bulleyed part 2. If I remember correctly losetoa6 got roughly only 4 inches compared to the 8 here. Sharp cutoff just west of Westminster and just east of the Baltimore/ Carroll county line.

I remember having that same experience in southern York county, PA. Amazing two part storm.
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28 minutes ago, AtlanticWx said:

This pattern definitely looks favorable, but how does it compare to the biggest Decembers around here?

Below is a plot of the mean snow-to-date climatologically in December from 1980-2021, along with the mean snow-to-date from the top 25% and bottom 25% Decembers snowfall-wise here in DC.Image

Out of those top 25 Decembers snowfall-wise, here are the H5 anomalies plotted on the Northern Hemisphere for each of them.Image

The key similarities to our upcoming pattern and the top 25% Decembers' average pattern around here are troughing near Hawaii/the Aleutians, a cutoff ridge north of AK and ridge bridging in the Arctic (-EPO/-AO/-NAO) and the elephant in the room -- lower heights over the EC.

Below is a composite plot of the 250mb plots in these same years (do note that they are smoothed out since they're for the entire month, but you can still make out two key features):This plot is not dissimilar to the PNA

The two key features here are an active STJ and what seems to be a Pacific jet extension, which promotes a +PNA if I remember correctly.

Our upcoming pattern seems to have an active STJ and a jet extension too, which is why we are expected to see a +PNA of some sorts during this pattern.
Overall, our pattern has key similarities to some other patterns of conducive Decembers, snowfall-wise.

Thanks for the breakdown! Question: When looking at H5 stuff...how do you identify an active STJ?

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24 minutes ago, HighStakes said:

That's right! I recorded 24 for the 2 part event. 16 inches with the heavy snow overnight into the morning. Then 1st part ended as some drizzle/ mist. Part 2 was very heavy snow for several hours that evening resulting in 8 more inches. Pretty sure this area bulleyed part 2. If I remember correctly losetoa6 got roughly only 4 inches compared to the 8 here. Sharp cutoff just west of Westminster and just east of the Baltimore/ Carroll county line.

Yep, there was 23" in Media Delaware County storm total just 13 miles southwest of Philadelphia International Airport.  What was amazing to me was the very heavy snow with winds out of the west blowing 35-50 mph. 

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6 minutes ago, Maestrobjwa said:

Thanks for the breakdown! Question: When looking at H5 stuff...how do you identify an active STJ?

No problem! STJs are visible on 250mb wind speed plots, and usually they're identified by stronger winds in the SE winds, and while this plot does smooth out the mean wind speed since it's a monthly composite, you can generally see stronger winds south of us, indicating an active STJ (sub-tropical jet).image.png.d313e285ed27c539228316a01107a196.png

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