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Central PA - Winter 2020/2021 Part 2


MAG5035
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This might be a bit long winded, but its how a look at things from a mental model frame and assigning certain
weights to things. People love to preach climitaology, and it is great for some aspects, I just feel the
time frame used and backwards looking nature of it combine to produce errors that are equivlent to an issue that
is a major theme in risk management, econocmics, etc; that is thinking everything falls under a perfect bell curve
and not being able to weight properly, low chance events, that might have a large impact. For example before the 1960's
nothing in the 100 years of recorded weather history in this area would have predicted what occurred, or if did it would
have been so unlikely as to disregard. The same thing happened in the last 25 years with large snow storms in this area.
The average snow each year straight constant, but the frequency of large storms shot through the roof. So part of the
issue is how you treat patterns that have different time periods as frequency and weight each one to see what is
likely.

On a much smaller scale, I find it out interesting how much people love the global ensambles here, but not a word
on the sref plumes. Usually you can get an idea of possible outcomes just by seeing what grouping the plumes fall under
and then if you look at the dx/dt you can get an idea of which one the trend is falling towards. I also try to take away
the top and bottom 3 to get a more realistic look at the median, mean along with where the different groupings lay and where
they start going apart from each other.


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4 minutes ago, Jns2183 said:

This might be a bit long winded, but its how a look at things from a mental model frame and assigning certain
weights to things. People love to preach climitaology, and it is great for some aspects, I just feel the
time frame used and backwards looking nature of it combine to produce errors that are equivlent to an issue that
is a major theme in risk management, econocmics, etc; that is thinking everything falls under a perfect bell curve
and not being able to weight properly, low chance events, that might have a large impact. For example before the 1960's
nothing in the 100 years of recorded weather history in this area would have predicted what occurred, or if did it would
have been so unlikely as to disregard. The same thing happened in the last 25 years with large snow storms in this area.
The average snow each year straight constant, but the frequency of large storms shot through the roof. So part of the
issue is how you treat patterns that have different time periods as frequency and weight each one to see what is
likely.

On a much smaller scale, I find it out interesting how much people love the global ensambles here, but not a word
on the sref plumes. Usually you can get an idea of possible outcomes just by seeing what grouping the plumes fall under
and then if you look at the dx/dt you can get an idea of which one the trend is falling towards. I also try to take away
the top and bottom 3 to get a more realistic look at the median, mean along with where the different groupings lay and where
they start going apart from each other.


.

That's a good read and I agree with this perspective. 

When I'm talking about climo, I'm referring very specifically to a weather event and what has previous events similar in nature impacted my area. If a 996 low centered directly over the Delmarva has brought mixing to my neighborhood over the past 56 years (my lifetime) and other factors are similar as well - I'm going to expect that mixing will occur from the current storm regardless of what models depict. If a clipper is approaching from the NW or even on a due W>E trajectory, history has shown that they often dry out crossing the mountains. 

So - I'm being very specific to how previous storms have affected Lancaster when most or all other parameters are the same. If the same storm strength and track has resulted in mixed bag events for me, I'm going to go out on a limb and expect a mixed bag event the next time, pretty snow maps be damned. 

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12 minutes ago, Homie J said:

Unfortunately this year we just get remote days instead.

Yea, the question of snow days is in question for the future but I think there is just a likely chance schools go right back to be mostly in room based and snow days may become a thing again in the future.  There is a large contingent of people who think remote learning is not working.  I have no opinion on that but it is pertinent in my opinion that remote learning may not be permanent.

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1 minute ago, Itstrainingtime said:

That's a good read and I agree with this perspective. 

When I'm talking about climo, I'm referring very specifically to a weather event and what has previous events similar in nature impacted my area. If a 996 low centered directly over the Delmarva has brought mixing to my neighborhood over the past 56 years (my lifetime) and other factors are similar as well - I'm going to expect that mixing will occur from the current storm regardless of what models depict. If a clipper is approaching from the NW or even on a due W>E trajectory, history has shown that they often dry out crossing the mountains. 

So - I'm being very specific to how previous storms have affected Lancaster when most or all other parameters are the same. If the same storm strength and track has resulted in mixed bag events for me, I'm going to go out on a limb and expect a mixed bag event the next time, pretty snow maps be damned. 

I think its a blended approach, because ens/analogs are always helpful, but knowing climo surely IS critical.....your boy Horst for example. 

Only fly in the ointment is that no 2 systems are alike and base state/tellies only help to narrow goalposts.  I think minor perturbations become more notable @40N because we often are ON the line or like i said earlier....ridin it.  Go to 37N or 43N and outcomes are far more predictable from a %;s perspecitve.  South assumes wet....north assumes white.  Around here we fight it out.  IMO mets in the N MA really earn their keep as nothing is clean and easy here.  

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4 minutes ago, Bubbler86 said:

Yea, the question of snow days is in question for the future but I think there is just a likely chance schools go right back to be mostly in room based and snow days may become a thing again in the future.  There is a large contingent of people who think remote learning is not working.  I have no opinion on that but it is pertinent in my opinion that remote learning may not be permanent.

I know several teachers.....your assesment is spot on.  Smart ones are fine...average/sub par.....notsomuch.  I've spoken personally w/ them about your very concern.

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8 hours ago, paweather said:

I get so sucked into the NAM precip panels that is my problem that I need to stop that. I should know better after all these years in this hobby the NAM is mostly overdone on precip on every storm. I need to remember to cut those panels in half. 

I usually cut the precip with the Nam in half. I figure that will probably be closer.

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7 minutes ago, pawatch said:

I usually cut the precip with the Nam in half. I figure that will probably be closer.

Funny thing is that except for a few off runs, the last few weeks NAM qpf maps have been underwhelming compared to the Canadians and the Euro.  May be a pattern thing.     The Icon has been qpf heavy at times as well. 

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HH NAM is about 1 move away from raining on my pre valentines eve activities. 
 
I wanna toss but fear we may be wet for Saturday.  This one isn’t trending well for LSV. 

Friday night is cold with lows below 20. If this a coming in Saturday night then I’d be much more worried about ice with how hard low level cold is a leaving here


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NWS Zone bullish for next Tuesday:

Monday Night
A chance of snow after 1am. Cloudy, with a low around 21. Chance of precipitation is 50%.
Tuesday
Snow likely, mainly before 1pm. Mostly cloudy, with a high near 33. Chance of precipitation is 70%.
Tuesday Night
A chance of snow. Mostly cloudy, with a low around 18. Chance of precipitation is 30%.
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3 minutes ago, pawatch said:

Bub sometimes in the last month it has sometimes been confusing what storm map I am looking at. You got to really study the times and dates. Which is a good thing that we are currently in a busy pattern!

Again thanks to everyone who takes the time to post.

 

And some innocently post the wrong map because the web site or browser did not update as they thought.  It happens in the MA forum every day I think.  LOL 

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15 minutes ago, Jns2183 said:


Friday night is cold with lows below 20. If this a coming in Saturday night then I’d be much more worried about ice with how hard low level cold is a leaving here


.

Yeah it may well be ice but verbatim we are close to a lot more taint. Not what I wanted to see. 

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Speaking of north trends and how often they occur - we haven't paid attention to tonight for a couple of days now, but tonight's wave looks like it might produce some snow much farther north than it did 24 hours ago. In fact, snow might very well make it up to DC tonight, last night it was buried some 90 miles further south. (aka, Bubbler's "King's Dominion" special) Doesn't affect us, but it's worth noting and filing away. 

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27 minutes ago, canderson said:

Meanwhile back home in Texas, there was a 130 car pileup in Fort Worth due to an icy interstate (35 West at 28th if you know the area). At least 6 have died. 

This video is banana. 


https://www.facebook.com/100003153511071/posts/3697402730374808/

 

OMG... 

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1 hour ago, pasnownut said:

FWIW EPS Ens is notably East of Op for both of next weeks storms.  Like lock that sh!t in kinda east....if they hold next week would flat out be best week of winter IMO.

 

12z EPS was indeed east of the Op for the Tuesday event & the Thursday possibility.

For the Tuesday event, Here are the low track clusters showing the transfer to the coast by a large group of ensemble members. This could put CTP in a great spot for more snow than mix if the coastal takes over at the right location.

36C1259B-1F55-4DCA-BAD3-CD5A294A10CA.png

7797C1D2-6D21-432C-AC86-822B409CF32B.png

318B86B6-704D-4B41-AAAD-A05B3BF169A8.png

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1 hour ago, losetoa6 said:

Gfs with a nice thump for Tuesday.  3hr snowfall maps showing 4-5" . I like the trends overall the past day or so for early week. 

Impressive 2m temps per Gfs . Soundings showing 14-16 F during the snow thump 

Yes, very nice snow thump on the 18z GFS! A good portion of CTP stays mostly snow, except for the southern tier, but by that point, a lot of snow is on the ground according to this run.

Here is the snow map for the Tuesday storm,

 

D984EC84-AD63-4BA9-A75F-AA121F812431.png

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