Jump to content
  • Member Statistics

    15,495
    Total Members
    7,904
    Most Online
    Mary M
    Newest Member
    Mary M
    Joined
The Iceman

2/10-2/12 Winter Storm Threat

Recommended Posts

3 hours ago, Ralph Wiggum said:

FV3CPO on board only a small break between waves. Better CAD and wetter.

fv3p_asnow_neus_15.png

That's 06z fwiw, FV3 on TT has been kind of sporadic lately for some reason...

  • Like 1

Share this post


Link to post
Share on other sites
2 minutes ago, KamuSnow said:

Straight 1:1 measurement, no conversion. Maybe clear your snowboard pre-sleet if you want to measure what has fallen vs. snow depth.

That's what I thought but I read Chesco's post and it says there is a period where he gets 3" IP. That's insane!!!

Share this post


Link to post
Share on other sites
4 minutes ago, Ralph Wiggum said:

That's what I thought but I read Chesco's post and it says there is a period where he gets 3" IP. That's insane!!!

Sounds like 2007, lol.

  • Like 1

Share this post


Link to post
Share on other sites
Just now, RedSky said:

Water expands when it freezes then break it into little pieces 1:1 feels like being short changed

 

I never liked how sleet was added to snowfall makes no sense....its not snow. I also dont like padding winter snowfall with fluke April snows. The latter I can accept moreso than the sleet thing but that's just me being picky. 

Share this post


Link to post
Share on other sites
5 minutes ago, RedSky said:

Water expands when it freezes then break it into little pieces 1:1 feels like being short changed

 

Maybe the 3:1 is the melted down liquid equivalent. I see it as frozen just denser than snow. Same goes for wet snow vs dry snow, it is what it is when it comes to measuring what's fallen.

Share this post


Link to post
Share on other sites

18z NAM doing even shorter of a break between waves. Bet it ends up without much of a break at all S of I276 maybe periods of flurries or intermittent light but continues to trend toward less and less of a gap window.

Share this post


Link to post
Share on other sites
4 minutes ago, Newman said:

18z NAM for the first wave. Cutback for areas north but increased southern areas. 

nam_2019-02-09-18Z_045_42.41_281.088_38.

Bet we see that swath of heavier snowfall tick N from here til showtime starting 0z run. Just a gut feeling based on past history.

Share this post


Link to post
Share on other sites

Okay I'll break down Berks County on the NAM.

 

Snow comes in around 9pm Monday evening and goes until 5am Tuesday before any mixing. Total snow around 4".

 

Sleet starts to mix around 5am Tuesday and lasts until noon or 1pm. Total qpf from sleet around 0.4" or so. That would come out to a little over an inch of sleet.

 

Total from wave one and wave 2: 5-6" of snow and 1.2" of sleet.

Share this post


Link to post
Share on other sites

3k NAM for wave 1:

nam3km_2019-02-09-18Z_048_42.598_280.167

 

Then snow picks up again around 8 or 9pm. Snowfall goes out to around 1am. Plenty more after this for some areas.

nam3km_2019-02-09-18Z_060_42.594_281.017

nam3km_2019-02-09-18Z_060_42.598_280.167

Share this post


Link to post
Share on other sites
2 hours ago, famartin said:

Kamu said I needed to provide some guidance on sleet here. Without reading the whole thread, can someone bring me up to speed?

I think we more or less sorted it out, but to summarize:

Is sleet counted as snow for snowfall totals, and at a 1 to 1 ratio? E.g., 3" of snow followed by 0.5" of sleet would be 3.5" of snow (especially if measured separately, as opposed to snow depth).

What is the LE ratio for sleet, about 3:1? Newman seems to have it nailed down at around 3.5:1.

There are the model output (snowfall map) issues where sleet may be added to total snowfall as if it was snow at a 10:1 ratio, but I think that can be sorted out by looking at soundings, upper air temps, qpf, snow depth maps, etc.

Thanks in advance Ray!

Share this post


Link to post
Share on other sites
16 minutes ago, KamuSnow said:

I think we more or less sorted it out, but to summarize:

Is sleet counted as snow for snowfall totals, and at a 1 to 1 ratio? E.g., 3" of snow followed by 0.5" of sleet would be 3.5" of snow (especially if measured separately, as opposed to snow depth).

What is the LE ratio for sleet, about 3:1? Newman seems to have it nailed down at around 3.5:1.

There are the model output (snowfall map) issues where sleet may be added to total snowfall as if it was snow at a 10:1 ratio, but I think that can be sorted out by looking at soundings, upper air temps, qpf, snow depth maps, etc.

Thanks in advance Ray!

3:1 or 3.5:1 is about right. Model snow map output continues to have issues discriminating. In any mix scenario I would always look closely at thermals for myself.

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, anthonyweather said:

 

In your head maybe

 

 

 

Yeah really. The difference between TT and Pivotal are like night and day...

Share this post


Link to post
Share on other sites
1 hour ago, anthonyweather said:

 

 


In your head maybe

6d2cf2a1a1a5ff0b7c17e6f7eac1c1ec.jpg


.

 

 

That is an inside joke sir. Most here know what it means to be NAM'd. Regardless that is poor practice to be using a kuchera based snowfall map in what looks to be quite an IP and fzra for parts of the interior.

I strongly suggest you pull up a skew-t and take a look around the region at thermal soundings from the 18z. A larger part of the event now shows sub 850s this run with a warm tongue and LOTS of sleet. So yes while that map you posted is likely more accurate for snowfall it is extremely misleading irt the IP/fzra potential with this CAD situation.

If you put the 10:1 snow map next to that map you posted the difference is mostly IP and that my friend is a big red flag. Again most people here (the group of like 10 of us that post here) know that is not all snow. Your subforum is going to have alot of ice issues.

  • Like 1

Share this post


Link to post
Share on other sites

0z NAM coming in colder 850s and juicier thru 34hrs across the Southern and SE portion of PA. Cut a bit on the N edge. Good start for our region at 0z with the first wave.

Share this post


Link to post
Share on other sites
3 minutes ago, Newman said:

0z NAM first wave:

nam_2019-02-10-00Z_039_42.562_279.96_38.

Wow theres close to a half foot snow in spots along the M/D line. No wonder there is more cold around for wave 2......snowpack.

Share this post


Link to post
Share on other sites

2m temps also colder at 7AM Tuesday on the NAM12k. 850 have surged above freezing but IP and fzra is ripping across parts of SE PA. Low level cold is just hanging on.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×