Central PA Winter 2022/2023

[Bubbler86]

23 minutes ago, dj88 said:

So I admit I am not an expert at reading models but I have learned a lot from all of you over the years but I have what is probably a dumb question lol. I only ever look at tropical tidbits so today I decided to look at Pivotal. Here's the dumb question. Same 12Z GFS run same frame 00Z on the 25th tropical shows 3 inches for my location and Pivotal shows 6 both on the 10:1 ratio. Why lol?

Each "model site" has algorithms, often different, they use to compute snow.  Tropical Tidbits computes sleet and snow on the same panel as you have probably read so their maps are often over inflated for snow fall totals vs. being under like you pointed out.  But I see what you are talking about in this case, and it is a bit strange as the presentation on the Tropical Tidbits precip maps would suggest more than 3" of snow would fall in your location.

Anyway, here is how Pivotal computes including the comments that it uses snow fallen.... not necessarily snow that will accumulate so that may be one clue to the difference.   They are discussing something similar in the MA thread and speed of the front among other things was mentioned as a possible explanation for inconsistent snow maps this run. 

 

https://home.pivotalweather.com/guides/snowfall

 

1. Our snowfall products generally attempt to forecast the snow that falls to the surface; not necessarily the snow pile you see on the grass, interstate, your rooftop, or anywhere else after a long storm. There are some caveats with Kuchera (penalizes warm temperatures in part to account for on-ground melting) and accumulated positive depth change (explicitly accounts for melting, albeit with model data file frequency as a confounding factor) — but none of these products will consistently provide an accurate forecast of final ruler-measured snow depth, even if the model’s QPF and vertical profile are spot on!

[pasnownut]

1 hour ago, Albedoman said:

thanks. I will be posting here more often. No I am not an elite but I do have 45 years experience in weather forecasting. I am a retired physical geographer with a concentration in atmospheric science _ the days before they had computer models outside of Maryland. I was an air traffic controller in the Navy and worked as a remote sensing for the CIA( landsat imagery). My uncle was the western regional director for the NWS until he retired 20 years ago- so yes I do know the weather before computers and the internet  got into the picture. I refer to models as tools of the trade and not the bible for storm forecasting.  I have seen every type of storm imaginable from being in an F3 tornado in Arkansas, hurricanes in MS, blizzards in the east coast,  125 degrees in death valley, 60 inches of snow in a single storm  in the mts of S California, dust storms, ice storms in Memphis Tn. and blistering cold of -25 degrees in wisconsin and my favorite -fog in the bay area so thick you have to get out of your car to see where you were at on the road. I just want to bring my experiences to the table to share with others and to simply tell your forum I am not some crackpot troller

 

 

Quite a resume any myriad of experience. Look forward to your sharing thoughts  

 

[canderson]

18 minutes ago, Bubbler86 said:

GFS has some near 30MPH winds in the Eastern LSV Friday afternoon....at 10M/33 feet above ground.   I am not really up on knowing the science of measuring how much mixing would occur down to the surface from 925. 

Haven’t looked at 12z runs but that’s sacked back from what I saw earlier. 10m had 55kt

 

if we don’t get anything over 35 I’ll consider than a win(d). 

[Bubbler86]

3 minutes ago, canderson said:

Haven’t looked at 12z runs but that’s sacked back from what I saw earlier. 10m had 55kt

 

if we don’t get anything over 35 I’ll consider than a win(d). 

Maybe we are looking at different time periods or I am reading the panel wrong.  I normally do not spend much time forecasting win(d) in lieu of using the NWS forecast.  Here is one of the higher panels I saw.   I noticed your win(d) comment.  LOL 

 

[dj88]

14 minutes ago, Bubbler86 said:

Each "model site" has algorithms, often different, they use to compute snow.  Tropical Tidbits computes sleet and snow on the same panel as you have probably read so their maps are often over inflated for snow fall totals vs. being under like you pointed out.  But I see what you are talking about in this case, and it is a bit strange as the presentation on the Tropical Tidbits precip maps would suggest more than 3" of snow would fall in your location.

Anyway, here is how Pivotal computes including the comments that it uses snow fallen.... not necessarily snow that will accumulate so that may be one clue to the difference.   They are discussing something similar in the MA thread and speed of the front among other things was mentioned as a possible explanation for inconsistent snow maps this run. 

 

https://home.pivotalweather.com/guides/snowfall

 

1. Our snowfall products generally attempt to forecast the snow that falls to the surface; not necessarily the snow pile you see on the grass, interstate, your rooftop, or anywhere else after a long storm. There are some caveats with Kuchera (penalizes warm temperatures in part to account for on-ground melting) and accumulated positive depth change (explicitly accounts for melting, albeit with model data file frequency as a confounding factor) — but none of these products will consistently provide an accurate forecast of final ruler-measured snow depth, even if the model’s QPF and vertical profile are spot on!

Thanks for the explanation!

[Bubbler86]

2 minutes ago, dj88 said:

Thanks for the explanation!

Sure but I could be wrong with that clue of snow fallen and was basically saying you found a strange difference.  Maybe someone else will have more factual thoughts than my guess.   But I love discussing model differences, so I thought I would throw out a thought. 

[canderson]

13 minutes ago, Bubbler86 said:

Maybe we are looking at different time periods or I am reading the panel wrong.  I normally do not spend much time forecasting win(d) in lieu of using the NWS forecast.  Here is one of the higher panels I saw.   I noticed your win(d) comment.  LOL 

 

You might be right and me misreading, that’s more likely. Maybe hit extreme wind, just strong advisory stuff? It still blows (see what I did there?) 

[paweather]

Should be a wild Friday rain, the canderson winds, and snow

[pasnownut]

My nooner obs from an hour ago. Top of 901 exit on 81 Will welcome any in search of a white Christmas. Centralia as well.
Now in Bloomsburg and view from third floor of communications dept after my meeting shows the elevational aspect of frosty tops and bare bottoms.

[pasnownut]

Oh and 27-29 degrees

[Bubbler86]

EC has some frozen in true Central PA Thursday afternoon....rain for the LSV and LV

[Bubbler86]

Friday accumulating snow is limited mostly to the West Central Mountains of PA on the EC.   Snow showers in the LSV.   And inch or two in the northern part of the MSV. 

[paweather]

5 minutes ago, Bubbler86 said:

EC has some frozen in true Central PA Thursday afternoon....rain for the LSV and LV

Not much in terms of post Frontal snow though. 

[Bubbler86]

2 minutes ago, paweather said:

Not much in terms of post Frontal snow though. 

Yea, it looks like the more typical front passage type snows.  Squalls and showers. 

[canderson]

Chicago might even mix in this storm lol - good job, good effort models 

[Bubbler86]

Just now, canderson said:

Chicago mixed mix in this storm lol - good job, good effort models 

LOL.  The GFS has 4-6" for Pittsburgh by Sat AM.  The Euro has a car topper that will be blown away anyway. 

[paweather]

Another snowless year geezus I am giving up winter canceled. 

[Mount Joy Snowman]

14 minutes ago, pasnownut said:

My nooner obs from an hour ago. Top of 901 exit on 81 Will welcome any in search of a white Christmas. Centralia as well.
Now in Bloomsburg and view from third floor of communications dept after my meeting shows the elevational aspect of frosty tops and bare bottoms.

I love when you can see that well-defined snow line on mountains.  We were driving up to Sunbury on Saturday morning for a family Xmas gathering and you could see a great example of the elevation-dependent nature of last week's storm on the "big" mountain that lies on the east side of the river just a few miles SSE of Selinsgrove.  It gets up to ~1,500' or so and the top few hundred feet were nice and white while the rest was bare.  I was keen on pointing it out to my wife, who let's just say, didn't find it quite as titillating as I did haha.

[Bubbler86]

1 minute ago, Mount Joy Snowman said:

I love when you can see that well-defined snow line on mountains.  We were driving up to Sunbury on Saturday morning for a family Xmas gathering and you could see a great example of the elevation-dependent nature of last week's storm on the "big" mountain that lies on the east side of the river just a few miles SSE of Selinsgrove.  It gets up to ~1,500' or so and the top few hundred feet were nice and white while the rest was bare.  I was keen on pointing it out to my wife, who let's just say, didn't find it quite as titillating as I did haha.

Your titillating reference easy outclasses my offering of vernacular.  Well played. 

[pasnownut]

24 minutes ago, Mount Joy Snowman said:

I love when you can see that well-defined snow line on mountains.  We were driving up to Sunbury on Saturday morning for a family Xmas gathering and you could see a great example of the elevation-dependent nature of last week's storm on the "big" mountain that lies on the east side of the river just a few miles SSE of Selinsgrove.  It gets up to ~1,500' or so and the top few hundred feet were nice and white while the rest was bare.  I was keen on pointing it out to my wife, who let's just say, didn't find it quite as titillating as I did haha.

I took a couple of pics for the doubters but they won’t upload. Too big. Yeah my wife thinks weather is a yawner as well and laughs at how much time I spend in search if it…and reading about it. 
Worse things to be doing I tell her. 

[Voyager]

21 minutes ago, pasnownut said:

I took a couple of pics for the doubters but they won’t upload. Too big. Yeah my wife thinks weather is a yawner as well and laughs at how much time I spend in search if it…and reading about it. 
Worse things to be doing I tell her. 

Post em to Facebook, copy the pic, then delete the Facebook post. That's how I post my pics here. Facebook automatically reduces the file size, which is then under the limit for attachments here.

[Albedoman]

The only thing that will break the fricking pattern we are in is the GOM opening up for business and at the same time a few clippers go on by.  Three years of this PA jet screaming by  is pissing off everyone now. Another  blown forecast for the LV  overcast and 31 degrees- was supposed to be sunny.  The La Nina has to relax in late January is our single chance of saving this winter. Wasted cold snaps by rain/mix and wind events is getting old. The only ones that will cash in on this ugly pattern is the Great lakes region for Lake effect snow as the lakes are not even frozen yet. What is strange is that we have very few true clippers in this crappy pattern. This is the 1980's all over again.

 

[Itstrainingtime]

5 minutes ago, Albedoman said:

The only thing that will break the fricking pattern we are in is the GOM opening up for business and at the same time a few clippers go on by.  Three years of this PA jet screaming by  is pissing off everyone now. Another  blown forecast for the LV  overcast and 31 degrees- was supposed to be sunny.  The La Nina has to relax in late January is our single chance of saving this winter. Wasted cold snaps by rain/mix and wind events is getting old. The only ones that will cash in on this ugly pattern is the Great lakes region for Lake effect snow as the lakes are not even frozen yet. What is strange is that we have very few true clippers in this crappy pattern. This is the 1980's all over again.

 

I was telling a few people this over the weekend. There were several winters that decade that produced so few chances...it was a lean period save for a few bigger events. On top of that, our knowledge was limited back then to TV 7 day forecasts...without being able to parse models and such, we couldn't even get a glimpse into all of our impending failures like we can today. 

[Bubbler86]

44 minutes ago, Voyager said:

Post em to Facebook, copy the pic, then delete the Facebook post. That's how I post my pics here. Facebook automatically reduces the file size, which is then under the limit for attachments here.

Another trick if on a PC/Mac (not mobile)  it is to bring them up on your screen, use a snipping tool to snip a shot of it,  then paste it into the post.   More cumbersome to do that on mobile though you can do it with a snipping app there as well. 

[paweather]

@Blizzard of 93when is our next tracking event I would like to uncancel winter. 

[MAG5035]

Models are narrowing the corridor for potential frozen on the front end, keeping it in the interior counties for the most part. Still a chance for the LSV to see some mixed depending on timing (faster) but it does appear that the best chance of anything accumulating stays west of the Sus river and likely closer to the I-99 corridor. Way too early look at the NAM…which has most of the front end phase in it’s range now is unimpressed thermally, with maybe a little bit of ice but not much in the way of any frozen anywhere. Will have to see how that evolves, one thing that occurred in the last event noted by CTP during the storm was models were a couple degrees too cold aloft, delaying the changover to snow that was supposed to occur for that. Different situation here, but a detail like that is something that could be the difference between a few inches of snow vs some mix and icing where models have been showing the corridor of snow. 

Either way, all of C-PA warms and any mix turns to rain ahead of the approaching rapidly deepening low and associated frontal boundary. It looks like the Sus Valley touches the 50s Thurs night into Fri morning with the rest of central and northern generally in the high 30s-low 40s. Frontal passage timing about late morning west to the mid-later afternoon east on Friday. 

Snow behind the front is still a big question mark of course. We’re probably going to have to wait for 3k NAM and HRRR time to really get a handle on that. Euro is really not printing much snow accums at all despite looking okay on the conditional maps.  GFS puts out a couple inches of snow in the Sus Valley. Since this has really turned into straight up lakes cutter event with no secondary coastal influence, I do kind of worry about the downslope component drying out the precip behind the front, especially the in the southern parts of the Sus Valley. Plus the GFS has seemed to have a knack for being overzealous on digital LSV snow as of late. I don’t have any problem seeing those types of accums in the western half of PA or the Laurels but it’s a big question mark from the ridge and valley part of PA eastward. I will say this, considering the very rapid temp drops behind the front and gusty winds, ANY kind of snowfall be it a dusting or whatever could quickly create hazardous conditions. And being this occurs on Friday afternoon/evening of Dec 23rd, I think travelers probably should be mindful of that. 

Lastly I think most of the area probably see winds of the advisory variety with and behind the front (and perhaps some breezy weather in the Sus Valley beforehand). Outside of potentially the Laurels, I don’t think we’ll see any prolific high wind warning type winds that one would think you’d see with a deep storm of this nature. Reason being is i think the more western track of the low may take the best pressure rises through Ohio, western PA and western NY. It will still be quite windy either way with low wind chills, especially Fri Night and Christmas Eve. 

[windycutter]

22 minutes ago, MAG5035 said:

Models are narrowing the corridor for potential frozen on the front end, keeping it in the interior counties for the most part. Still a chance for the LSV to see some mixed depending on timing (faster) but it does appear that the best chance of anything accumulating stays west of the Sus river and likely closer to the I-99 corridor. Way too early look at the NAM…which has most of the front end phase in it’s range now is unimpressed thermally, with maybe a little bit of ice but not much in the way of any frozen anywhere. Will have to see how that evolves, one thing that occurred in the last event noted by CTP during the storm was models were a couple degrees too cold aloft, delaying the changover to snow that was supposed to occur for that. Different situation here, but a detail like that is something that could be the difference between a few inches of snow vs some mix and icing where models have been showing the corridor of snow. 

Either way, all of C-PA warms and any mix turns to rain ahead of the approaching rapidly deepening low and associated frontal boundary. It looks like the Sus Valley touches the 50s Thurs night into Fri morning with the rest of central and northern generally in the high 30s-low 40s. Frontal passage timing about late morning west to the mid-later afternoon east on Friday. 

Snow behind the front is still a big question mark of course. We’re probably going to have to wait for 3k NAM and HRRR time to really get a handle on that. Euro is really not printing much snow accums at all despite looking okay on the conditional maps.  GFS puts out a couple inches of snow in the Sus Valley. Since this has really turned into straight up lakes cutter event with no secondary coastal influence, I do kind of worry about the downslope component drying out the precip behind the front, especially the in the southern parts of the Sus Valley. Plus the GFS has seemed to have a knack for being overzealous on digital LSV snow as of late. I don’t have any problem seeing those types of accums in the western half of PA or the Laurels but it’s a big question mark from the ridge and valley part of PA eastward. I will say this, considering the very rapid temp drops behind the front and gusty winds, ANY kind of snowfall be it a dusting or whatever could quickly create hazardous conditions. And being this occurs on Friday afternoon/evening of Dec 23rd, I think travelers probably should be mindful of that. 

Lastly I think most of the area probably see winds of the advisory variety with and behind the front (and perhaps some breezy weather in the Sus Valley beforehand). Outside of potentially the Laurels, I don’t think we’ll see any prolific high wind warning type winds that one would think you’d see with a deep storm of this nature. Reason being is i think the more western track of the low may take the best pressure rises through Ohio, western PA and western NY. It will still be quite windy either way with low wind chills, especially Fri Night and Christmas Eve. 

I must say, nice write up. In addition, being located at the very base of the Laurel Mountains, wind is generally strong here.  My area had some damage with the past storm. 

[Bubbler86]

4 minutes ago, windycutter said:

I must say, nice write up. In addition, being located at the very base of the Laurel Mountains, wind is generally strong here.  My area had some damage with the past storm. 

Was the damage from wind while the trees were still encased in ice?  

[TheDreamTraveler]

Sucks that snow chances kinda evaporated for the 23rd. I was excited about potentially having a white christmas. :< i guess i'll just be happy about it being warm at least so that's nice for me imo

[windycutter]

4 minutes ago, Bubbler86 said:

Was the damage from wind while the trees were still encased in ice?  

No ice!  WAA here. CAD does not occur due to being just west of the ridge.