Central PA Winter 25/26 Discussion and Obs

[Jns2183]

Yeah there are always some looney tune reports in those PNS releases but they offer a good big picture view.  Aaaaahhhh so you do measurements every hour and sum them?  That would explain your big total.  I believe NWS guidance for snow measurements is every 4 or 6 hours, someone can correct me.  Not hounding ya for doing it that way, just offering some color as to why people report such varying totals.

Truthfully it depends on how much I want to sleep and how much snow is blowing, and if it's different precipitation types. I truthfully try to shoot for 3 hours that are lined up exactly with the main model times because I'm a data junkie. But I did have almost exactly the same as that trained spotter 3 miles from my house when he did his report

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[Mount Joy Snowman]

14 minutes ago, CarlislePaWx said:

I am good friends with Dave Robinson, the NJ State Climatologist.  He, along with several other state climatologists reached a consensus on the measuring protocol about 20 years ago. Together, the protocol was adopted by the NWS and should be the protocol used for all NWS-related measurements for snow/sleet.   The correct answer to how frequently to clear the snow board is every 6 hours.  Anything more often than that, as you can see, will inflate the total progressively higher as you continue to clear the board more frequently.  I don't think I've ever heard of anyone taking hourly readings followed by clearing the board.  (I'm not picking on you.  It's just that I am certain I know how to do the snowboard measurement since I've been doing it that way (to the best of my ability) ever since.)  There are additional steps that are to be taken when there is the introduction of sleet.

Agreed.  I think you intended this message for JNS?  I was the one pointing out that him doing the hourly measurements likely inflated his totals and that it should be done every 4, or as you've now clarified, 6 hours. 

[Summit Snow]

Don't get above 20 through Sunday up here. 

EURO and ICON have coastal bomb for next Sunday.

[philliesmd]

56 minutes ago, WmsptWx said:

There's something funny about a flight to a weather conference being canceled, assuming due to weather lol. 

 

Assuming it's weather unless we lost all the Air Traffic dicks and I hadn't read about it. 

Hey now, I used to be one of those air traffic dicks. 

[Superstorm]

Canadian is a blizzard.


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[GrandmasterB]

I’d love to track another one this week. This is how to run a winter! 

[anotherman]

1 minute ago, Superstorm said:

Canadian is a blizzard.


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This is not very far away, either.  Hopefully all the models agree early so people can prepare.  Could be very impactful for the area.

[Jns2183]

I am good friends with Dave Robinson, the NJ State Climatologist.  He, along with several other state climatologists reached a consensus on the measuring protocol about 20 years ago. Together, the protocol was adopted by the NWS and should be the protocol used for all NWS-related measurements for snow/sleet.   The correct answer to how frequently to clear the snow board is every 6 hours.  Anything more often than that, as you can see, will inflate the total progressively higher as you continue to clear the board more frequently.  I don't think I've ever heard of anyone taking hourly readings followed by clearing the board.  (I'm not picking on you.  It's just that I am certain I know how to do the snowboard measurement since I've been doing it that way (to the best of my ability) ever since.)  There are additional steps that are to be taken when there is the introduction of sleet.

What do you do for sleet?
I had 8.5" at 11. This was also when rates were great. One of reasons I started taking them more frequently in this storm was because the breeze was starting to blow the supper dry snow around and I wasn't confident in the new location I placed the snow board. If you can point me too the correct protocol id appreciate it

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[sauss06]

next event is for Sunday correct, February 1st?

[AccuChris]

12z GFS is very close to being an epic blizzard but still just a little too far east. Not a bad place to be at this time


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[Jns2183]

Canadian is a blizzard.


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Maybe we can do a reverse 1996 where we had the 22" storm and 5 days later a 11"

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[canderson]

9 minutes ago, sauss06 said:

next event is for Sunday correct, February 1st?

Sundays to Monday yea   This is a monster 

[Festus]

Winds starting to kick up but I see zero signs of drifting here.  We ended up with a nice crust on top so that should tame the drifting potential.  One less pita to contend with.

[CarlislePaWx]

16 minutes ago, Jns2183 said:

What do you do for sleet?
I had 8.5" at 11. This was also when rates were great. One of reasons I started taking them more frequently in this storm was because the breeze was starting to blow the supper dry snow around and I wasn't confident in the new location I placed the snow board. If you can point me too the correct protocol id appreciate it

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Hey...

I just sent you a DM.  Check it out.

[canderson]

30 minutes ago, Festus said:

Winds starting to kick up but I see zero signs of drifting here.  We ended up with a nice crust on top so that should tame the drifting potential.  One less pita to contend with.

Snow is blowing off roofs but anything on pavement is concrete at this point here 

[Jns2183]

There were 17 seasons where the official Harrisburg station recorded 14" plus in a 2-day or less event since 1890. Here are the stats
Statistics for these 17 Seasons:
Count: 17
Mean: 49.91"
Std Dev: 18.54"
Median (50%): 47.20"
Min: 23.90"
Max: 81.30"
25th Percentile: 38.00"
75th Percentile: 57.70"

For 12" plus
Statistics for these 31 Seasons:
Count: 31
Mean: 45.82"
Std Dev: 16.39"
Median (50%): 39.50"
Min: 23.90"
Max: 81.30"
25th Percentile: 34.95"
75th Percentile: 54.45

For 10" plus
Statistics for these 48 Seasons:
Count: 48
Mean: 42.90"
Std Dev: 15.12"
Median (50%): 39.30"
Min: 18.40"
Max: 81.30"
25th Percentile: 33.50"
75th Percentile: 50.85"

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[Jns2183]

Where do we go from here? Analyzing 21.7" by Jan 25th (Harrisburg/Middletown)
Hey eve

With our current seasonal total sitting at 21.7" as of January 25th, I decided to dig into the historical archives for the Middletown-Harrisburg area to see how this stacks up and what "history" says about the rest of our winter.
I looked at every season since 1899 to find years that met or exceeded our current 21.7" by today’s date. Here’s the breakdown:
The Historical Analogues
There are 28 seasons in our history that reached this mark by Jan 25th.
* Average Final Total: 48.4"
* Snowiest Year in this Group: 1960-1961 (Finished at 81.3")
* Least Snowy Year in this Group: 1987-1988 (Finished at 26.7")
What’s Left in the Tank? (Snow after Jan 25th)
Looking only at what fell after today’s date in those 28 seasons:
* Average remaining snow: 17.6"
* Median remaining snow: 15.5"
* The "Boom" Scenario: 1993-1994 added a massive 45.6" after Jan 25th!
* The "Bust" Scenario: 1953-1954 only added 1.5" more.
The "Confidence" Forecast
Based strictly on these 28 historical matches, here is the probability for our final seasonal total:
* 90% Certainty: We finish with at least 27.1"
* 75% Certainty: We finish with at least 30.6"
* 50% Certainty (The Coin Flip): We finish with at least 37.2"
* 25% Certainty: We finish with at least 47.7"
* 10% Certainty (The Longshot): We finish with at least 53.4"
Context: The Big 2-Day Hitters
For those wondering about the "big one," here are the top 2-day totals ever recorded in our data:
* 30.2" (Jan 22-23, 2016)
* 25.0" (Feb 11-12, 1983)
* 22.2" (Jan 7-8, 1996)
* 21.0" (Jan 15-16, 1945)
* 20.4" (Mar 13-14, 1993)
Summary: History suggests we are about 55-60% of the way through our seasonal snowfall. If we follow the "average" of our historical peers, we're looking at another 17" or so before spring.
What do you guys think? Do we follow the 1994 path (+45") or the 1954 path (+1.5")?


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[Jns2183]

Correlation
Is a snowy start a predictor of a snowy finish?
General Correlation: Across all years since 1899, the correlation is nearly zero (0.08). In the broad historical sense, a snowy start to winter does not guarantee a snowy end.
Qualifying Years Correlation: Interestingly, when looking only at the 28 seasons that started as snowy as this one, the correlation increases to 0.24.
Interpretation: While the general rule is that early snow doesn't predict late snow, in "active" years like this one, there is a slight positive trend. History suggests that when the pattern is active enough to give us 21.7" by late January, it tends to stay slightly more active than a typical year through the spring.

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[canderson]

Snow is melting off my sidewalk - nice to see actually 

[Jns2183]

Google model

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[MickeyTim6533]

EURO just whiffed

[AccuChris]

12z Para Canadian was improved for the coastal


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[anotherman]

12z Para Canadian was improved for the coastal


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That looks further offshore than the regular Canadian.

[2001kx]

11.5" storm total 

[AccuChris]

That looks further offshore than the regular Canadian.

It is, but it is a big improvement over its own 0z run last night


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[pawatch]

Storm total 10”

I have 300’ of drive I cleared 4 times with a snowblower during the storm. 

Finished cleaning everything up at 11:00 am this morning.

Send the next one      

[canderson]

Another day, another day with winds 15 mph above forecast. Blowing 40. 

[WmsptWx]

I can't imagine what current and former TV mets are dealing with right now. But I can't imagine this is the only crash out ongoing.

[canderson]

He should talk to CTP who has this in their latest disco. 
 

KEY MESSAGE 2: Potential East Coastal Storm Threat this weekend

There is a growing guidance signal and slightly westward trend/earlier phasing of short waves and amplification of a large scale trough for the development of a potentially impactful weekend coastal storm along the Eastern Seaboard. We will continue to closely monitor this given risk of snow and
wind impacts.

The track and intensity of the surface moving north-northeast just off the Carolina and Delmarva coasts would lead to a higher east/northeast wind threat during the storm, and stronger
NW winds in its wake.

 

[Burghblizz]

10 minutes ago, WmsptWx said:

I can't imagine what current and former TV mets are dealing with right now. But I can't imagine this is the only crash out ongoing.

I think weather apps (esp apple weather) are probably a bigger culprit than random online weather weenies. Those apps are “trusted sources” and are flashing huge snow totals in the extended range. Of course for many, those at least directionally verified after they did it for this past weekend. So I can see people putting more faith in it.