Central PA - Winter 2020/2021

[MAG5035]

11 minutes ago, Wmsptwx said:

If everyone in forum gets 10 plus, this will be my fav storm in memory. We always talked about it, but to see it really happen would be just awesome. Hoping kpit uses ratios to get to over 6 as well.

How do you feel about good ole Williamsport being a snow chasing destination for this storm? Haha

[2001kx]

Pretty sure they got close to 20" just a couple years ago didnt they?

wmsptwx? 

Good luck to you and everyone on here...

[Santa Clause]

Just now, 2001kx said:

Pretty sure they got close to 20" just a couple years ago didnt they?

wmsptwx? 

Good luck to you and everyone on here...

Yes sir 18 in 2017. My fav storm to date.

[2001kx]

Just now, Wmsptwx said:

Yes sir 18 in 2017. My fav storm to date.

I thought so..You are the hot spot now (well i guess we'll see tomorrow)

[MillvilleWx]

37 minutes ago, Blizzard of 93 said:

Oh yes, I want thunder snow too!

@MAG5035 or @MillvilleWx or @psuhoffman

How is the thunder snow chance looking now?

Looking at mean soundings over a general area, the best chance for TSSN will be located across eastern PA near the Pocono's, but there is a secondary shot between 00-06z Thu over central PA within the deformation axis. There's a bit of conditional instability for a time between Harrisburg and State College during the height. It's not a slam dunk imo, but I can see some thunder for sure in places. 

[Winter Wizard]

Had to make the trip back to Happy Valley for this storm! Looks like for the first time in a long time, this entire subforum will be the jackpot zone, hope you all enjoy. 

[Blizzard of 93]

Here is the 0z UKMET...the 0z party continues for CTP.

[Blizzard of 93]

0z Euro still looks good for all of CTP.

I added the total precip map to give an idea of where the max zones look to set up this run. It also indicated very little mixing in the LSV this run.

[tim123]

Can you post ensemble mean when it comes out?

[Blizzard of 93]

The 0z EPS still looks good and even improved slightly for our southeast crew.

 

[MAG5035]

Way too early look at the 6z HRRR which extends out on the 0,6,12,and 18z runs seems to jive okay with things. 

For some obs here, it's a nice crisp 26ºF currently with some increasing clouds and a light easterly breeze. 

[so_whats_happening]

Current Obs of KBWI:

Quite windy over here right now having 13 knots gusts to 20knots out of the ENE 

Temp 32/19

Was chatting with a met from OPC and we both were in agreement this is the beginning portion of the arctic air. Would really like to see that dew point drop to the low teens say 12-13F to show the depth of the cold pool. Line sits around AVP/Allentown/ to just south of NYC with that nose of arctic air. Low temps and matching low dew points, single digits.

Lets have some fun nowcasting today can't wait to just see how it all unfolds regardless of what I get back at home in the Lancaster area.

[paweather5]

[paweather5]

[kerplunk]

Area Forecast Discussion

National Weather Service State College PA

315 AM EST Wed Dec 16 2020

SHORT TERM /9 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Main changes to the short term grids (the main event) were to
nudge the axis of the heaviest accums to the NW by 20-30 miles
and add a little, too. This is in line with a slight shift west
of the dry slot and best slant-wise instability (for the banded
structures). Latest model QPF and SLRs argue for even higher
numbers with State College and Williamsport in an axis of 24+"
accums. We will not take it to that extreme of a change in
either axis of the highest accums nor the SF totals. But, a
nudge in that direction seems prudent.

[paweather5]

[Heisy]

5 hours ago, MillvilleWx said:

Looking at mean soundings over a general area, the best chance for TSSN will be located across eastern PA near the Pocono's, but there is a secondary shot between 00-06z Thu over central PA within the deformation axis. There's a bit of conditional instability for a time between Harrisburg and State College during the height. It's not a slam dunk imo, but I can see some thunder for sure in places. 

Hey man, I have plans to go to Williamsport Pa today, but I’m starting to think while they will do amazing, maybe a bit farther south or east willl do even better... I’m trying to find the jackpot!!! Lol im A greedy bastard...anyway.this happened during the storm I chased to New England earlier this year where things shifted east on the meso models real close to the event (literally then12z NAM while I it was precipitating) and I had to drive 45 mins southeast)..any spots you’d recommend as well? Just trying to get all sorts of recommendations b4 I go. Thanks!!

[kerplunk]

5 minutes ago, Wentzadelphia said:

Hey man, I have plans to go to Williamsport Pa today, but I’m starting to think while they will do amazing, maybe a bit farther south or east willl do even better... I’m trying to find the jackpot!!! Lol im A greedy bastard...anyway.this happened during the storm I chased to New England earlier this year where things shifted east on the meso models real close to the event (literally then12z NAM while I it was precipitating) and I had to drive 45 mins southeast)..any spots you’d recommend as well? Just trying to get all sorts of recommendations b4 I go. Thanks!!

Lewistown

[MAG5035]

24 minutes ago, kerplunk said:

Area Forecast Discussion

National Weather Service State College PA

315 AM EST Wed Dec 16 2020

SHORT TERM /9 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Main changes to the short term grids (the main event) were to
nudge the axis of the heaviest accums to the NW by 20-30 miles
and add a little, too. This is in line with a slight shift west
of the dry slot and best slant-wise instability (for the banded
structures). Latest model QPF and SLRs argue for even higher
numbers with State College and Williamsport in an axis of 24+"
accums. We will not take it to that extreme of a change in
either axis of the highest accums nor the SF totals. But, a
nudge in that direction seems prudent.

That portion of the disco hasn't been updated since about 10 last night. However, overnight and early morning guidance (6z) have continued to support that notion of a 24+ axis somewhere between I-99 and I-81 northeastward toward the Poconos. Exactly where is likely going to eventually be determined by today's near term guidance as the event unfolds. Still trying to adjust to the fact that we're trying to pinpoint the highest totals within a nearly region wide foot plus in all guidance for us haha. 

I think CTP has a good handle with their current snow map. I do like that general area of Lewistown to Selinsgrove up to Williamsport for the best opportunity to get to two feet or perhaps beyond. For State College I'm thinking 14-18", but definitely a shot to get past 20 or so. Gonna depend how far back those CSI bands set up the first half of this evening, and to a lesser degree how well the storm accumulates rate and ratio wise during the WAA phase of precip today. If State College does get into the thick of it, I'd look at the 7 mountains region of US 322 between there and Lewistown for something ridiculous. Again, this is pinpointing where these excessive totals might pop up within the general 10-20" this whole region stands to see.

Making a fairly safe call of 14-16" for the backyard (Altoona), it's weird saying that much is a "safe" call haha. They're sort of in the same boat as State College with perhaps the outside chance of seeing 20. 

 

[MillvilleWx]

6 minutes ago, Wentzadelphia said:

Hey man, I have plans to go to Williamsport Pa today, but I’m starting to think while they will do amazing, maybe a bit farther south or east willl do even better... I’m trying to find the jackpot!!! Lol im A greedy bastard...anyway.this happened during the storm I chased to New England earlier this year where things shifted east on the meso models real close to the event (literally then12z NAM while I it was precipitating) and I had to drive 45 mins southeast)..any spots you’d recommend as well? Just trying to get all sorts of recommendations b4 I go. Thanks!!

Anywhere here. Lewisburg is probably where I would setup. I see them 20-24" with up to 30" possible

[kerplunk]

6 minutes ago, MAG5035 said:

That portion of the disco hasn't been updated since about 10 last night. However, overnight and early morning guidance (6z) have continued to support that notion of a 24+ axis somewhere between I-99 and I-81 northeastward toward the Poconos. Exactly where is likely going to eventually be determined by today's near term guidance as the event unfolds. Still trying to adjust to the fact that we're trying to pinpoint the highest totals within a nearly region wide foot plus in all guidance for us haha. 

I think CTP has a good handle with their current snow map. I do like that general area of Lewistown to Selinsgrove up to Williamsport for the best opportunity to get to two feet or perhaps beyond. For State College I'm thinking 14-18", but definitely a shot to get past 20 or so. Gonna depend how far back those CSI bands set up the first half of this evening, and to a lesser degree how well the storm accumulates rate and ratio wise during the WAA phase of precip today. If State College does get into the thick of it, I'd look at the 7 mountains region of US 322 between there and Lewistown for something ridiculous. Again, this is pinpointing where these excessive totals might pop up within the general 10-20" this whole region stands to see.

Making a fairly safe call of 14-16" for the backyard (Altoona), it's weird saying that much is a "safe" call haha. They're sort of in the same boat as State College with perhaps the outside chance of seeing 20. 

 

Thanks for the clarification and analysis. Always have problems getting the "previous" portions straight with the update time.

Those CSI band locations are always a crap shoot - even during the height of a storm. 

[MAG5035]

3 minutes ago, kerplunk said:

Thanks for the clarification and analysis. Always have problems getting the "previous" portions straight with the update time.

Those CSI band locations are always a crap shoot - even during the height of a storm. 

Your welcome, and actually CTP has just updated their disco. They got all the good details in there haha. 

Quote

.NEAR TERM /THROUGH TONIGHT/...
Loop of the Nighttime Microphysics channel shows mid and high
cloud shield spreading steadily NE and thickening up across PA
in advance of what looks to be a likely record-breaking snow
storm for December (with respect to both 1 and 2 day snow totals
at Harrisburg, State College and Williamsport that were mainly
in the lower to mid teens).

Temps ranged from the mid teens across Tioga County, where
minimal cloud cover occurred for the longest period earlier in
the overnight, to the mid 20s in the south.

Winds were mainly from the east at 5-10 kts with some minor
gusts.

A major winter storm will impact central PA this afternoon
through Early Thu morning, with snow accumulations of 1-2 feet
expected, and snow rates as high as 2-4 inches per hour Wed
night.

Very little change was made to the previous snow totals, except
for adding some small variations in snow totals based on
elevation within the axis of heaviest snow from the Scent Mtns
to the Middle Susq Valley and Western Poconos, and tacking on a
few inches across Mckean County - placing them in 18-24 hour Winter
Storm Warning criteria acrs the SE half of the County.

All model guidance is in very good agreement with respect to
the evolution, track, and intensity of the consolidating and
intensifying sfc along the Delmarva Coast early tonight.

Expect a high probability for over 1 foot of snow within the
region bounded by I-81 and I-80, with as much as 20 inches in
spots from Scent PA, to the Western Poconos and Endless Mtns
region NE of KIPT.

This target area will see a one-two (maybe even three) punch of
warm advection heavy snow later this afternoon and evening,
followed by a period of peak CSI-banded heavy snow with the
potential for Thunder snow later this evening through a few
hours after midnight as the nose of a strong, 50-60 kt easterly
850 mb jet and 130 kt upper jet focuses hefty uvvel and
slantwise instability near and just to the NW of the I-81
corridor.

Intense snowfall rates of 3-4 inches per hour will accompany
these CSI bands, which will make travel extremely difficult to
near impossible with very poor vsbys and road conditions.

Concerning the onset timing of the snow, latest HRRR runs have
the snow beginning along the southern PA border around 15Z (10
AM EST), around noon along Interstate 80, and 1-2 pm across the
northern tier.

Model simulated reflectivity and snowfall rates steadily ramp up
across the southern half of PA between 18-20Z and early this
evening across the Northern Tier of PA.

A host of 00/06Z Wed Op Model/Hi-Res EFS data continues to
indicate the likelihood of a mid/upper level (700-500 mb) dry
slot surging NE across the region near and to the east of the RT
15/I-81 corridor in the Lower Susq Valley and Western Poconos
later this evening through the first half of tonight.

Max wet bulb temp in the 925-700 mb layer near the nose of the
anomalously strong eastern LLJ will poke up into the 0 to 3C
range near and to the south of a line from Gettysburg to York
and Lancaster in the 012-05Z Thursday period which is near the
time of peak precip rates.

After the lead surge of WAA moderate to heavy snow, some sleet
should mix in near and to the southeast of a York-Lancaster line
Wed evening, trimming the snowfall amounts by several inches or
more.

This feature aloft and its impacts on precip type and snow accum
rates will keep us honest in displaying at least a gradual
gradient to lesser snow amounts of only 9-10 inches across far
southern York and southern Lancaster Counties, while much
heavier amounts of snow fall to the NW of I-81.

This will be the time when snowfall rates near and just to the
NW of the I-81 corridor will be 2-4 inches per hour in
developing CSI bands.

If the NW extent of this warm wedge doesn`t make it that far
north to cause some sleet, our Lower Susq Valley counties could
be under the gun for near Blizzard Conditions.

Thundersnow is possible early tonight near and to the NW of the
I-81 corridor.

Cold Conveyor belt/FGEN moderate snows with near 1 inch per hour
snowfall rates should linger until around, or shortly after
daybreak from KUNV to KIPT and points NE, leading to the axis of
heaviest snow near or just to the SE of that axis with some
areas seeing 18-20 inches for high-end storm total amounts.

The storm will be relatively quick moving, with most places
seeing precip for 18-24 hours. Nonetheless, with cold
temperatures in place, good SLRs, and very strong frontogenesis,
this should end up being the most significant snowstorm for
most of the area since November 2018... and for some areas,
perhaps one of the heaviest snow events in the past 5+ years. It
also may rival some of the record 1-day and 2-day December snow
totals. For reference, the December 2-day record snowfall at
Harrisburg is 13.9 inches, set in 1961.

Also, they have a climo section for record snowfall.. which this is poised to break 2 day largest snowfalls for December in all the CTP climo stations (UNV, IPT, MDT).

Quote

.CLIMATE...
The last time there was 12+" of snow over a two day period (as
many storms will cross from one date into another):

State College:  6-7 Feb 2010 = 14.0"
Harrisburg:   20-21 Mar 2018 = 14.2"
Williamsport: 14-15 Mar 2017 = 18.4"

Last time there was an 24+" storm (not sayin`, just sayin`):

State College:  3-4 Mar 1994 = 27.7"
Harrisburg:   22-23 Jan 2016 = 30.2"
Williamsport: 12-13 Jan 1964 = 24.1" (the only two-foot storm
for Williamsport)

Highest two-day total:
State College: 29-30 Mar 1942 = 30.5"
Harrisburg:    22-23 Jan 2016 = 30.2" (that one, again)
Williamsport:  12-13 Jan 1964 = 24.1" (that one, again)

 

[Blizzard of 93]

58 minutes ago, paweather5 said:

That’s the best GEFS run yet...wow!

[Blizzard of 93]

1 hour ago, paweather5 said:

This is the best GFS run yet for the LSV....just wait until @pasnownut sees this run for his backyard!

[sauss06]

Good morning all.............Looks like we stayed the course overnight. Bring it home now fellas..

screw you 2020, its gone snow 

[Superstorm]

Good luck to everyone.. Finally.....Winter is here!!


.

[pasnownut]

51 minutes ago, Wentzadelphia said:

Hey man, I have plans to go to Williamsport Pa today, but I’m starting to think while they will do amazing, maybe a bit farther south or east willl do even better... I’m trying to find the jackpot!!! Lol im A greedy bastard...anyway.this happened during the storm I chased to New England earlier this year where things shifted east on the meso models real close to the event (literally then12z NAM while I it was precipitating) and I had to drive 45 mins southeast)..any spots you’d recommend as well? Just trying to get all sorts of recommendations b4 I go. Thanks!!

Selinsgrove

 

[sauss06]

13 minutes ago, Superstorm said:

Good luck to everyone.. Finally.....Winter is here!!


.

Seems like its been years. This has me all pumped up like the Christmas snow in '02. I think i'll grab 3 fingers of Bourbon and write a Hallmark story 

[pasnownut]

47 minutes ago, MAG5035 said:

That portion of the disco hasn't been updated since about 10 last night. However, overnight and early morning guidance (6z) have continued to support that notion of a 24+ axis somewhere between I-99 and I-81 northeastward toward the Poconos. Exactly where is likely going to eventually be determined by today's near term guidance as the event unfolds. Still trying to adjust to the fact that we're trying to pinpoint the highest totals within a nearly region wide foot plus in all guidance for us haha. 

I think CTP has a good handle with their current snow map. I do like that general area of Lewistown to Selinsgrove up to Williamsport for the best opportunity to get to two feet or perhaps beyond. For State College I'm thinking 14-18", but definitely a shot to get past 20 or so. Gonna depend how far back those CSI bands set up the first half of this evening, and to a lesser degree how well the storm accumulates rate and ratio wise during the WAA phase of precip today. If State College does get into the thick of it, I'd look at the 7 mountains region of US 322 between there and Lewistown for something ridiculous. Again, this is pinpointing where these excessive totals might pop up within the general 10-20" this whole region stands to see.

Making a fairly safe call of 14-16" for the backyard (Altoona), it's weird saying that much is a "safe" call haha. They're sort of in the same boat as State College with perhaps the outside chance of seeing 20. 

 

Really glad to see you in the hunt for this one.  I"m feeling a bit better after seeing early am runs (for a chance at 12").  I'll take some sleet and let the crew to the N and W fight over who wins the big prize (which when we are looking at 12+24" accums is sorta crazy - but hey, it's a doozy and they don't happen all too often.

Gonna be a good day no matter what happens or doesnt.  It's gonna snow, and if there werent computer models to tease us....we'd all just be glad to see it falling.

Enjoy.

[pasnownut]

15 minutes ago, Blizzard of 93 said:

This is the best GFS run yet for the LSV....just wait until @pasnownut sees this run for his backyard!

GIIIDDDDDYYY up gang.

It's T-3 till go time.