Central PA Winter 2022/2023

[Ruin]

Someone explain to me with blocking as strong as it is up north that hasn't changed how is the system going More Northwest or north of the coast

[pawatch]

NWS first guess.

[Bubbler86]

4 minutes ago, Ruin said:

Someone explain to me with blocking as strong as it is up north that hasn't changed how is the system going More Northwest or north of the coast

The blocking is why the system is "stopping" in the midwest and reforming south of us.  The reason we are not getting a MAJOR snowstorm despite a system going south of us is the lack of cold air around right now.  No room for error.     So, in short, the blocking is "working" but the air is moderate at best. 

[Eskimo Joe]

4 minutes ago, Ruin said:

Someone explain to me with blocking as strong as it is up north that hasn't changed how is the system going More Northwest or north of the coast

Blocking is great, but you need an antecedent high pressure over Quebec to force northeast flow and the low and mid levels to lock in the cold. We don't have that so it let's the coastal rush south/southeast winds in and flip us to liquid. 

[Ruin]

24 minutes ago, Bubbler86 said:

The blocking is why the system is "stopping" in the midwest and reforming south of us.  The reason we are not getting a MAJOR snowstorm despite a system going south of us is the lack of cold air around right now.  No room for error.     So, in short, the blocking is "working" but the air is moderate at best. 

Fair but all I hear is cold air I'd in place from local news I'm surprised it's going up the coast is what I mean 

[pasnownut]

38 minutes ago, Ruin said:

Someone explain to me with blocking as strong as it is up north that hasn't changed how is the system going More Northwest or north of the coast

 

8 minutes ago, Ruin said:

Fair but all I hear is cold air I'd in place from local news I'm surprised it's going up the coast is what I mean 

think of the neg NAO as a cold dome.  That dome is prevalent here in the east, but storms can go "around" that dome.  The primary is trying to cut to the left side of said dome, and the secondary is a result of the dome shredding the primary apart, and that energy needs to find some other source to keep it going...thats the eastern coastal waters.  The cold  forces that energy to "transfer" south of the dome and typically close to the eastern seaboard.  

The primary screws up the thermals for us by enhancing SW flow and gets our mid/lower levels above freezing.  We then wait for the coastal to "pop" off the coast, and with the counter clockwise circulation, we get wind flow backing from the N/NW/W which taps into the colder side of the storm, and warm mid/lower levels (aka column) cools sufficiently to transition wet back to white.    When we say there are many ways to fail...2 pronged systems like this just up the odds of missing out on pure clean white gold from a Miller A (one LP coming out of the south) and not a Miller B (one primary system hands off to a secondary system - which is sorta what weve got in front of us.  

Hopefully this helps to understand the current situation evolving.

[Ruin]

Highs in mud to upper 30s lows in teens low 20s for this time of year is cold. Let's hope it trends colder 

[Blizzard of 93]

3 hours ago, Superstorm said:

GFS starting to show that thump potential.


.

Yes, the 18z run starts all of us off with a mix changing to snow for the eastern half of PA. If the precip rates are moderate to heavy, dynamics could help the snow potential with marginal temperatures.
If the low jumps from the central Chesapeake out to well off of the NJ coast like this run shows, we could really be in business.

[Blizzard of 93]

Here is the 18z GFS snow map through Friday.

[Cashtown_Coop]

1 hour ago, pawatch said:

NWS first guess.

I like the map.  Looks like Cashtown has become an official site on the map.  

[Blizzard of 93]

The 18z Euro has also improved snow chances for the LSV & shows the thump potential as well.

The Euro tracks the low from Central NC Thursday afternoon to near Cape May, NJ by early Friday am.

[Blizzard of 93]

Here is the 18z Euro snow map.

[Blizzard of 93]

3 hours ago, MAG5035 said:

Model evolution since my last posting on Saturday has generally trended toward a more progressive secondary coastal low. And when I say “progressive” I mean it keeps on tracking into New England and beyond vs a  stall and capture situation. That of course would take the Dec ‘92 2+day storm scenario off the table.

What we seem to be looking at with this is a primary wave of warm advection precip that progresses into the region on Thursday, that perhaps enhances as we get development on the coast. Since this keeps moving, we’re going to be on more of a time crunch to get the column right for all snow. Basically, this is the scenario mentioned last week  with the far west cutting primary hitting the blocking and forcing secondary development.  We will have CAD and the actual secondary low on the coast (which wasn’t being modeled much at all at that point), so think most of the subforum sees a mix event up front, transitioning to snow in the interior counties as the coastal low gets going. Further south LSV (LNS/THV) is going to be dependent on coastal track as the low lifts up (could transition to rain if it’s too close) while upper LSV places like Harrisburg eventually transition to a period of snow. CTP mentioned in their AFD about dynamic and evaporative cooling of the column as well, which could imply a situation where the initial precip shield ends up being a thump of snow after brief early mixing.

To put all of this simply, it’s going to be difficult to resolve p-type issues for awhile yet… per usual. 

Great post!

This will be a fascinating storm to track.

The best part is that we should have a couple of more storm chances to track as we approach the holidays!

[GrandmasterB]

Dang that Euro would work! 

[pasnownut]

38 minutes ago, Cashtown_Coop said:

I like the map.  Looks like Cashtown has become an official site on the map.  

Yeah has some of us in the game as well.  Hope so cause IF the 18z was correct, we then head from riding the line to suppression depression as a parade of storms head for da fishys off the SE coast and we go cold n dry.

 

 

[pasnownut]

31 minutes ago, Blizzard of 93 said:

Great post!

This will be a fascinating storm to track.

The best part is that we should have a couple of more storm chances to track as we approach the holidays!

Dont look at the 18z GFS pal (says jokingly as its JUST ONE RUN!!) 

[Blizzard of 93]

1 minute ago, pasnownut said:

Yeah has some of us in the game as well.  Hope so cause IF the 18z was correct, we then head from riding the line to suppression depression as a parade of storms head for da fishys off the SE coast and we go cold n dry.

 

 

We are going to be doing a lot of tracking between now & the holidays…buckle up!

[Blizzard of 93]

22 minutes ago, GrandmasterB said:

Dang that Euro would work! 

The 18z Euro ensemble also improved for the LSV & CTP in general.

The mean low tracks from eastern NC/VA border to the DelMarVa coast near OCMD to near Atlantic City, NJ.

 

 

[Blizzard of 93]

The 18z Euro ensemble snow map also increased snow amounts for the LSV this run.

[pasnownut]

10 minutes ago, Blizzard of 93 said:

We are going to be doing a lot of tracking between now & the holidays…buckle up!

Yeah, it looks like fun times for us sno trackin weenies

[mahantango#1]

What is with all the flocks of geese headed south? This has been going on for days now. Seems a little late for them to be leaving now. Seems they know something what's coming with the weather.

[Blizzard of 93]

CTP is starting to ramp up the Thursday potential…

A potentially significant winter storm will brew over the central CONUS and spread into Pennsylvania on Thursday, lasting into
Friday.

[pasnownut]

12 minutes ago, Blizzard of 93 said:

The 18z Euro ensemble snow map also increased snow amounts for the LSV this run.

 

I had a little time to play on pivotal and the Ukie actually improved at 12 and isnt too far from decent for us LSV'rs,  Just trying to get a feel for what the current model "spray" is...and I'd say the goalposts are not too wide for this lead time.  

[Blizzard of 93]

Great discussion from CTP this evening,

”Clouds Wed evening steadily lower/thicken-up late Wed night. Precip may arrive in the Laurel Highlands as early as midnight Wed night, and push northeastward towards the I-99 and I-80 corridor by sunrise Thu. Nearly all model guidance has a nose of warm air (+5C) at about 4-5 kft during the onset of precip, maximized over Somerset county. This will likely result in freezing rain for Somerset and Cambria counties during the morning Thu. Our preliminary freezing rain totals call for up to 0.25 inch of ice in the higher terrain of Somerset and Cambria Counties. Freezing rain impacts could be exacerbated by strong southeasterly winds, sustained 15-20 mph with gusts 30-40 mph. Strong winds and freezing rain may result in tree and powerline damage. As precip continues to overspread central PA during the daylight hours Thu, it will push into colder air. Although max wetbulbs aloft may be above freezing at the onset of precip, evaporative and dynamic cooling should bring the temp and td below freezing as the heaviest precip develops. Model guidance suggests the period from about 15z Thu - 00z Fri Thu will feature deep isentropic ascent and a fully saturated troposphere, with substantial upward motion in the DGZ aided by frontogenesis between 700-500 hPa. Our preliminary snowfall forecast calls for 4-6 inches of snow accumulation from AOO northeastward towards Potter and Tioga counties during this period of time. Gusty winds could result in reduced visby during moderate or heavy snow. After 00z Thu, the forecast becomes more uncertain. Warm air will advect northward, likely bringing the rain-snow line towards or even north of I-80. A dry slot aloft will significantly reduce the depth of the saturated layer, potentially resulting in the loss of ice within the clouds for a portion of the CWA. This part of the forecast depends largely on how quickly a secondary coastal low can develop - a stronger coastal low developing more quickly along the Mid Atlantic coast can draw in colder air to and more moisture, resulting in more snow accumulation Thu night into Fri. Additional snow accumulations during this period are most likely in our northeastern zones. Precip type, storm track, and storm intensity are still complicating factors that contribute to uncertainty at this time. We will continue to provide updates over the next few days as the system approaches and the forecast becomes more certain.”

 

[canderson]

Anyone wants Modest Mouse tickets for the Thursday show in Philly? /angry

[CoralRed]

4:30a: Williamsport and a lot of the middle of the state just got a Winter Storm Watch at 4:25:

WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH FRIDAY MORNING...

* WHAT...Heavy mixed precipitation possible. Total snow accumulations of 4 to 8 inches and ice accumulations of around one tenth of an inch possible.

 

Thursday

Snow, freezing rain, and sleet, becoming all snow after 8am. High near 34. Southeast wind 9 to 14 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New snow and sleet accumulation of 3 to 5 inches possible.

Thursday Night

Snow before 4am, then rain between 4am and 5am, then snow after 5am. Low around 34. Chance of precipitation is 100%. New snow accumulation of 1 to 2 inches possible.

Friday

Snow before 8am, then rain likely. High near 39. Chance of precipitation is 80%.

[CoralRed]

More about Thursday-Friday from 4:05a Area Discussion: 

A pair of jet left exit regions arriving one after the other from the southwest will provide at least two periods of stronger forcing that could meld together and create steady moderate to heavy snow with rates of 1-2 inches per hour at times Thursday afternoon and evening, coinciding with the period of strongest llvl easterly flow.

Although this upcoming event is an open wave embedded in the SW flow aloft, the increasing upper diffluence, and rapidly developing coastal low over the Delmarva Region Thursday night will create the potential for some heavy snow totals in excess of 10 inches across parts of the Central and Northern Mtns.

Previous Disc...

[CoralRed]

5:15a More from the Williamsport Night Crew:

From weather.com's 14 day forecast snow chances for right before Christmas.

Thur Dec 22 50% Day 1-3; Night 1-3

Fri Dec 23 60% Day 1-3; Night 3-5

Sat Dec 24 50% Day 1-3

Temps stay below 32 from Thur night through at least the following Tues night. Let us see what we get.

 

[WmsptWx]

Anyone wants Modest Mouse tickets for the Thursday show in Philly? /angry

You should be angry for liking Modest Mouse lol

Sent from my motorola edge 5G UW (2021) using Tapatalk

[Bubbler86]

A chilly 22 this AM.

@canderson, the meso's I just looked at have your whole trip just rain by 1-2PM Thurs....if that is time enough to go.   Nam 3K has you rain in the AM.