Western Pa / Pittsburgh area Winter Discussion ❄️☃️

[KPITSnow]

1 minute ago, Mailman said:

Seems to me it is just falling in line with the other guidance finally.

I’m pretty sure kuchera totals are usually wildly too high. What is the 10:1 totals?

[Ahoff]

2 minutes ago, Mailman said:

Seems to me it is just falling in line with the other guidance finally.

Oh, 11.7” is still good I was expecting it to say like 8”, lol.

[Mailman]

10:1 is better for me.

[Ahoff]

Just now, Mailman said:

10:1 is better for me.

Still nice!

[southpark]

Just now, Ahoff said:

Oh, 11.7” is still good I was expecting it to say like 8”, lol.

8 would still be great! How often do we get storms that are 8 inches? I get we all want more but I will take this and run with it.

[KPITSnow]

Here is the newer NAM totalQPF. 
 

https://mag.ncep.noaa.gov/Image.php

you can see the notable shifting East in the qpf field. 

[KPITSnow]

3 minutes ago, Mailman said:

10:1 is better for me.

That’s better than I thought. I think we will have a good idea where things are heading based on the GFS though.

[Ahoff]

26 minutes ago, southpark said:

8 would still be great! How often do we get storms that are 8 inches? I get we all want more but I will take this and run with it.

I agree, and 8 in this set up is pretty good too.

[Ahoff]

25 minutes ago, KPITSnow said:

That’s better than I thought. I think we will have a good idea where things are heading based on the GFS though.

Totals were down for everyone on that run, there really aren't any over 2' like all day.  The GFS isn't that great, and like people have said, it's time to move to the mesos, and at some point tomorrow, real time.

[MikeB_01]

Positive thought on the NAM.. We were happy with the 00z run last night. Tonights run is essentially a carbon copy. 

 

Its crunch time now. We can watch the models come in tonight, but we all know that this is coming down to watching its progression tomorrow morning.

[jwilson]

Well, this is the last minute trend we were worried about.  Seems we're now running into a consensus and that takes the truly more impressive totals off the table for PIT.  Eight inches is not a bad event, but now we're getting to the point where that looks like our absolute max instead of closer to the lower or middle end of averages.  It's a fast reversal of the trend that favored us for a couple days, but it also means that trend could continue into tomorrow.  Hopefully not.

Analysis - 

0Z 3K NAM is unequivocally worse for PIT.  With the 18Z NAM, we had snow from 18Z Wednesday (1 PM) until 8Z Thursday (3 AM).  1-1.25" QPF, which actually cut back from 12Z (which was mostly 1.25" in the entire county with a small blip of 1.5") and 6Z (similar).  At 0Z, half the county gets only .5 while the eastern edge gets .75.  Most of Allegheny gets 6" with no high spots.  12Z and 18Z hit a foot in spots (with the former hitting a foot over the entire county).  That's off the table for now.

Timing is generally the same; onset at 17-18Z and ending at 8Z Thursday (very light).  The biggest difference is this run keeps PIT outside of all the major deform bands and under generally lesser snowfall rates.  You can see the compacting of the precip shield with this 0Z NAM run.  The western side of the system looks much drier than before.  It snows for 12 hours or more and we get 6" of snow for it.  You can do the math and see that the rates are mostly abysmal.

The best snow growth - according to the 3K - happens during the beginning of the storm.  We maximize lift only one hour after the onset (2nd hour of snow) which is followed by one more hour of good lift, but then after that, it's largely garbage snow growth.  To my novice eyes, it looks like there are much stronger westerly winds above the surface leading to dry air intrusion, thus effecting ratios.  There's also considerably less omega and as I understand it, cold air advection (which is sinking, not rising air).

These decreases are additionally reflected in the SREF plumes, which dropped substantially.  The average on 15Z approached a foot; it is now down to 8.5" or so.  Instead of more than a dozen members over 12", only two now.  The majority (18) are still clustered between eight and twelve inches, however.  Only eight members are under the average.  That's obviously a flinch but not a total loss.  These totals are usually overdone regardless, IIRC.

All the other mesoscale models dropped our totals, as well, except the RGEM which kept them steady.  The WRF-HMM is the most progressive, by far, and gives us only 2-3" in Allegheny.  The ARW2 went from an absurd 18-20" down to a "measly" 6-10" (which is likely far more accurate, but it still is a considerable difference).

The last thing I'd say is that, once again, this is going to come down to mesoscale features of the system.  I don't like our odds of hitting 12" anymore, perhaps less than a 2% chance, but our floor hasn't really decreased much, if at all.  4-8" is a safe bet with no shutouts on the table, at least.  Hopefully this trend doesn't continue.  It does, however, look like the precip shield will ultimately be less impressive and more susceptible to dry air inundation on the western edge.

[Mailman]

0z GFS:

[KPITSnow]

The GFS is a disaster. Maybe 2-4 inches.

It literally never fails. It is going to be so much fun to watch the returns die as they come over the mountains lol.

[jwilson]

I wanted to add this bit of analysis, even if it's a tad stale by now.  One of the more under-rated aspects as to why the 12Z NAM and 0Z NAM gave us such different results could be because of a northern shortwave pressing down less on the overall picture.  First we see the 12Z NAM run:

In this view, we can see that northern stream piece of energy fluxing a "mini trough" down over Minnesota.  This, in turn, lowers the heights and contours of the overall Eastern CONUS trough and raises heights along the East Coast.  What that means: it forces the energy and the associated low with the coastal to ride a more westerly track and tuck farther into the Delmarva area (even into the Chesapeake).  It heads more north or NNE instead of just NE or even east.  However, the 0Z changes that piece of energy:

The 0Z NAM makes this piece of energy far less relevant.  In that sense, the s/w has less overall effect on the trough and allows for a more progressive or flatter look to the heights along the East Coast.  The associated low can then escape quicker or, at least, take less of an "amplified" track that would otherwise force it into Delaware or southern PA.  The main energy now sweeps across New Jersey and south of D.C. instead of right over the urban corridor.  That's enough of a difference to take us out of the main game, so to speak.

I would imagine the models have a better handle on all these energies now closer to game-time.  If that's true then it's an unfortunate result, but not totally unforeseeable.

[blackngoldrules]

So sorry to hear about your loss, can't even pretend to understand how that would affect you on so many levels. Glad you are back and I hope you can enjoy tracking with us again. Looks like we may be on the verge of snatching victory from the jaws of defeat on this next one. 

Thank you. I really appreciate that. I'm not going to lose sleep or get all emotional over this hobby anymore. I've been through too much to let a missed or disappointing storm bother me, but I do want to get some enjoyment out of it again and do some tracking again. Whatever happens happens.

[KPITSnow]

What I really want to know is how the modeling can be so consistently wrong in our area so close to events. How many times have we been within 24-48 hours of an event being modeled for a significant storm only to see it be reduced to either nothing or an advisory level event?

[MikeB_01]

As i sit here watching the 00z suite come in, the PA central folks jump for joy, and the morale of our own group wains faster than our snowfall totals. For a moment, I am going to put my rose-colored glasses on and try to keep a few things in perspective.

1. Models have been trending in our way all day. 1-2 model runs back in the other  direction doesn't kill our dreams.

2. 6-8 is still a really good storm and this is what I think the most of us will still see. Is it 30? no, but we will keep hoping for that.

3. Storms that ride up from the south like this always seem to amplify more than what the models think. Remember Jan 2016 --I was thinking 3-4" event and it over amplified into a 9" storm for me. On the other side, Jan 2019-- the models had us constantly on the mix line. Snow to mix and back to snow, hoping to get 3-4 " out of it. It over amplified again and we rained for nearly the entire storm.  So if the models are trending a little lower in your area, keep in mind that these things have a tendency to go a little NW than what the models think.

4. I will enjoy the snow falling down tomorrow regardless of if we get 4, 6, 8, 10 or 12.  But im hoping for 12!

Enjoy your night everyone.

[Rd9108]

I'm going to bed but here's one last model for your viewing. Is anyone except KPIT really gonna be upset about something like this? We will get our 2ft storm eventually we are due. 

[north pgh]

4 minutes ago, Rd9108 said:

I'm going to bed but here's one last model for your viewing. Is anyone except KPIT really gonna be upset about something like this? We will get our 2ft storm eventually we are due. 

Agree. Let’s enjoy the snow tomorrow. We should see some nice rates late afternoon. 

[2001kx]

11 minutes ago, Rd9108 said:

We will get our 2ft storm eventually we are due. 

 

I dont know...I have been waiting 27 years now for my 2' snowstorm 

 

[north pgh]

2 minutes ago, 2001kx said:

I dont know...I have been waiting 27 years now for my 2' snowstorm 

 

1993 me too!

[tim123]

2 feet snowstorms in Pittsburgh is a once in a lifetime event. 

[2001kx]

Just now, tim123 said:

2 feet snowstorms in Pittsburgh is a once in a lifetime event. 

Yep same for Clearfield apparently.

[tim123]

I feel for you guys in Pittsburgh. Just a bad spot geographically. I am in rochester ny we get a 2 foot snowstorm once every 10 years id say. Foot snowstorm almost every year.

[tim123]

Lake ontario helps alot. 

[Heisy]

Hey guys. I’m headed to Williamsport tomorrow. I know that isn’t really your region, but just wanted to visit different forums. I went Cal U back in 05 in their meteorology Program. It was before I really knew about how CAD worked. I quick learned the downside lol. Hope you guys do well to because that probably means more for me as well!

[tim123]

Lots of 3 to 5 inch snow falls throughout. So we get over 100 inches annually. Hope you guys get atleasta half a foot tomorrow. 

[north pgh]

Don’t know if anyone is still up. I believe the euro still looks pretty good.

 

[Burghblizz]

Yeah Euro is fine. I don’t think this ever was going to be a 15”+  storm here.

The last 4 storms that cracked 15” (93/94/03/10) all had huge closed lows. It’s too progressive.

Overall good trends in the last 36 hours overall to get it to something significant. So need to keep that perspective. Still think 6-8” is a good bet. Maybe touching 10” in eastern areas.

 

[blackngoldrules]

Winter Storm Warning

URGENT - WINTER WEATHER MESSAGE National Weather Service Pittsburgh PA 315 AM EST Wed Dec 16 2020
PAZ014>016-021-022-029-031-073-075-WVZ021-509-161615- /O.CON.KPBZ.WS.W.0004.201216T1200Z-201217T1200Z/ Butler-Clarion-Jefferson PA-Allegheny-Armstrong-Washington-Greene- Westmoreland-Fayette-Marion-Monongalia- Including the cities of Butler, Clarion, Punxsutawney, Brookville, Pittsburgh Metro Area, Kittanning, Ford City, Washington, Canonsburg, Waynesburg, Murrysville, Greensburg, New Kensington, Lower Burrell, Latrobe, Monessen, Uniontown, Fairmont, and Morgantown 315 AM EST Wed Dec 16 2020

...WINTER STORM WARNING REMAINS IN EFFECT FROM 7 AM THIS MORNING TO 7 AM EST THURSDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 6 to 9 inches.

* WHERE...Portions of northwest, southwest and western Pennsylvania and northern West Virginia.

* WHEN...From 7 AM this morning to 7 AM EST Thursday.

* IMPACTS...Travel could be very difficult. The hazardous conditions could impact the morning or evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency.

Please report snow or ice by calling 412-262-1988, posting to the NWS Pittsburgh Facebook page, or using Twitter @NWSPittsburgh

The Pennsylvania Department of Transportation and Pennsylvania Turnpike Commission strongly encourage motorists to heed all travel restrictions and delay unnecessary travel. Visit www.511pa.com for the latest travel, roadway and traffic conditions.