Jump to content
  • Member Statistics

    16,895
    Total Members
    7,904
    Most Online
    Pszemo
    Newest Member
    Pszemo
    Joined

Western Pa / Pittsburgh area Winter Discussion ❄️☃️


north pgh
 Share

Recommended Posts

3 minutes ago, stjbeautifulday said:

I’m just trying to learn from everyone.  It seems to my very inexperienced eye, the kuchera is always way higher totals than what we either expect or end up getting?  How come?  

We have colder air to give us better ratios. The standard ratio is 10:1. 

Link to comment
Share on other sites

11 minutes ago, stjbeautifulday said:

I’m just trying to learn from everyone.  It seems to my very inexperienced eye, the kuchera is always way higher totals than what we either expect or end up getting?  How come?  

Basically a guy  named Kuchera came up with a complicated formula. We like it because it usually shows more snow. So you will see it more on this forum. 

But what I think it is is a formula that uses  the highest temp found at 500 mb, and thus can account for temps in the column a little better.

I think the intial intent was to project how much compacting will take place, but it does usually show more than 10:1 unless there is a lot of sleet. 

Thats basically what I remember - but I mostly like it because it shows more snow 

  • Weenie 1
Link to comment
Share on other sites

If you're rooting for snow, time to hope the south trend stops immediately.  The Euro is probably the southernmost model right now - at least in terms of shearing off the northwest quadrant of the precip shield - but it isn't pretty.  The seasonal trend had been to deamplify systems and kick them south, prevent phasing, etc.  It is possible we're headed back to that norm with the Thursday event.

The NAM has been dropping this system south for four straight runs now.  The GFS jumped from Athens, OH to Athens, GA in a 24-hour period.  Like the last storm there are warning signs, including some of the misplaced upper level features, but we won't really know until we know.

Link to comment
Share on other sites

Any more SE shift at all and I think our chance at even advisory level snowfall is sunk.

I think NWS has me at about 3.8 on the point and click, which is roughly half of what I had as recently as this morning. This one is disappearing as quickly as yesterday’s storm, but in the other direction.

Link to comment
Share on other sites

27 minutes ago, jwilson said:

If you're rooting for snow, time to hope the south trend stops immediately.  The Euro is probably the southernmost model right now - at least in terms of shearing off the northwest quadrant of the precip shield - but it isn't pretty.  The seasonal trend had been to deamplify systems and kick them south, prevent phasing, etc.  It is possible we're headed back to that norm with the Thursday event.

The NAM has been dropping this system south for four straight runs now.  The GFS jumped from Athens, OH to Athens, GA in a 24-hour period.  Like the last storm there are warning signs, including some of the misplaced upper level features, but we won't really know until we know.

18z Euro is ugly, 1-2 inches tops. I agree the South trend needs to stop, all the models have gone further and further in that direction consistently one run to the next. Another move like that in the Euro is partly cloudy skies. 

Link to comment
Share on other sites

44 minutes ago, Burghblizz said:

Basically a guy  named Kuchera came up with a complicated formula. We like it because it usually shows more snow. So you will see it more on this forum. 

But what I think it is is a formula that uses  the highest temp found at 500 mb, and thus can account for temps in the column a little better.

I think the intial intent was to project how much compacting will take place, but it does usually show more than 10:1 unless there is a lot of sleet. 

Thats basically what I remember - but I mostly like it because it shows more snow 

It tries to calculate based on temperature at various levels, in a borderline scenario it would likely give you a truer outcome as it will assume less than 10:1 or if it's colder it would assume higher ratio. It also tries to take into account melting / compaction as you mentioned. 

Here's a good read from pivotal about the slr calculations: https://home.pivotalweather.com/guides/snowfall

Snow maps are also flawed in that they use the temperature at a given forecast period then assume all qpf that falls after it will have the same conditions until the next interval. So image hour 3 all layers are below zero, then hour 4 850 goes above but the next interval isn't until hour 6, your going to have 2 hours of qpf assumed snow that is a mix.

Link to comment
Share on other sites

15 minutes ago, Rd9108 said:

So basically we are back to our norm of being too far south or north to get snowfall. 

Seems that way. This winter helped me forget this is the way it almost always works in Pittsburgh, so I wasn’t as prepared as I would normally be for the models completely falling apart with a drastic last minute NW shift, then two days later completely falling apart with a drastic last minute SE shift.

It’ll be interesting to see what today’s final snow total is at the airport. Today could be the snowiest day of the week when it’s all said and done.

Link to comment
Share on other sites

HREF for thursday- friday. 

 

Something interesting that is showing itself on the hires models is another dry slot just like we had with this past storm. Looks like i would snow thursday morning, take a break and then start back up with another round. Havent been seeing that on some of the mid range models. 

 

No matter, the HREF just like all other guidance at this point is focusing in on 2-4 over the course of 18-24 hours.  Maybe we can get the last second jog to the NW. Doubt it, but maybe.

 

Screen Shot 2021-02-17 at 12.54.27 AM.png

Link to comment
Share on other sites

I'm hopeful that we see at least a slightly different outcome. I feel like we've seen this pattern a few times this season where my whole family in Maryland looks teed up for a big one only to get 1-2" while we get 6". Is that high pressure in New England/southern Canada throwing us off the course? It seems to bounce around an awful lot with each model run. It went from sitting near the lakes earlier in the week to sitting right over Maine/Massachusetts as of late. 

Link to comment
Share on other sites

NAM 12km doesn't look bad.  3-6" on 10:1, so I'd imagine bumping it up with Kuchera, as temps don't really get above 27 or 28 through the duration.  At least NAM has start time within a day at this point.

NAM 3km, also pretty good at 4-5" at 10:1.  Temperatures creep to near 30, but never quite make it.

And SREFs up to almost 6.5".

We are still in this.  The short range look good, and I'd say we're in short range as this is to start right after midnight.

Link to comment
Share on other sites

7 minutes ago, Ahoff said:

NAM 12km doesn't look bad.  3-6" on 10:1, so I'd imagine bumping it up with Kuchera, as temps don't really get above 27 or 28 through the duration.  At least NAM has start time within a day at this point.

NAM 3km, also pretty good at 4-5" at 10:1.  Temperatures creep to near 30, but never quite make it.

And SREFs up to almost 6.5".

We are still in this.  The short range look good, and I'd say we're in short range as this is to start right after midnight.

Also of note, from a quick glance it looks like all the 6z runs at least halted the South trend, if not a very minor subtle improvement. I don't think it would take much to increase the qpf a bit more on the NW edge with a few slight adjustments. f we can squeeze another 5in or more storm out of this that would be a win. Overall it looks like the bigger totals out east are also coming down somewhat, where the good qpf is it's also mixy so..

Link to comment
Share on other sites

11 minutes ago, north pgh said:

At this point I would take this. If it snows for 12 hours at a 1/4 inch per hour that is fine with me. If we over perform and get 3-5 or 4-6 than much better. It’s game time. Let’s go!

My thoughts exactly. I hope the eastward hault that we saw with the 06z suit continues and even comes a little west. Might be able to get that 3-5 if that happens.

  • Like 1
Link to comment
Share on other sites

38 minutes ago, Ecanem said:

GFS doesnt show major snow totals for us but it also brings the rain/sleet line almost to allegheny county.

GFS has stopped the bleeding with the SE shift, which is good.

NWS still wants to keep the “heavy at times” wording in for both tomorrow and tomorrow night in our area, despite forecasting only 2-3 inches of snow. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...