Feb 16-17th Winter Storm

[Hoosier]

Wonder if any office is going to feel confident enough to pull the trigger on a winter storm watch with the overnight package.  Obviously not the greatest confidence in where the heavy snow band will be, but with an ice component in play, maybe could get away with one for combined impacts even with lower than usual confidence.

[Chicago Storm]

Browsing through NAM soundings, and they are supportive of TSSN potential.

[Cary67]

3 minutes ago, Hoosier said:

Wonder if any office is going to feel confident enough to pull the trigger on a winter storm watch with the overnight package.  Obviously not the greatest confidence in where the heavy snow band will be, but with an ice component in play, maybe could get away with one for combined impacts even with lower than usual confidence.

Especially if Euro bumps south on OZ run

[Radtechwxman]

3 minutes ago, Hoosier said:

Wonder if any office is going to feel confident enough to pull the trigger on a winter storm watch with the overnight package.  Obviously not the greatest confidence in where the heavy snow band will be, but with an ice component in play, maybe could get away with one for combined impacts even with lower than usual confidence.

Yeah that's a tough call. Getting close to that window. We are like 48hrs or so from possible wintry impacts but model agreement not the greatest. Worse than it was with GHD III at this range. 

[ILSNOW]

2 minutes ago, Cary67 said:

Especially if Euro bumps south on OZ run

Chicago NWS prolly wait to afternoon package to put up watches if needed.

[Chicago Storm]

0z GEFS mean

[ILSNOW]

Look at this precip map has to be overdone but by how much

[hlcater]

Interesting to see that LOT graphic basically mimic the GFS in terms of heavy snow spread. Must think the rest of guidance is out to lunch.

Wonder if we can get some insight on that decision? Seems bold to go with a model that is objectively the outlier.

[Powerball]

3 hours ago, AWMT30 said:

We get 2-3" of sleet here in Canton on the NAM kind of would want to see that happen 

As someone who has suffered through 10 houra of nonstop Sleet and got roughly that exact amount in accumulation, no you don't.

I mean, it's better than freezing rain, but only by the slimmest margin.

[Stevo6899]

Gfs/nam prob too far north. Ukmet/Canadian are similar, kinda euroish. I think if the euro holds serve later, gfs/nam can prob be considered outliers. With the last system, they were too far north at this point also. We shall see.

[Air Traffic Control]

I guess I have to resign myself in heavy rain because I don't want that ice. Of course, still jealous of the snow just too far north! Maybe one day St. Claire County will get snow en masse. XD

Time to find an updated ice projection...

[Powerball]

2 minutes ago, Stevo6899 said:

Gfs/nam prob too far north. Ukmet/Canadian are similar, kinda euroish. I think if the euro holds serve later, gfs/nam can prob be considered outliers. With the last system, they were too far north at this point also. We shall see.

The upper levels with this systems are definitely more supportive of a further NW/stronger storm than GHD III.

[Hoosier]

22 minutes ago, ILSNOW said:

Look at this precip map has to be overdone but by how much

I think some earlier runs had an area of 3" qpf

[fluoronium]

16 minutes ago, Chicago Storm said:

Browsing through NAM soundings, and they are supportive of TSSN potential.

What do you look for on a forecast sounding to identify thundersnow potential? I see the NAM has mid level lapse rates in excess of 7C/km and MUCAPE values over 100J/kg in areas receiving frozen precip. There is a lot of shear as well. Is there anything else to be looking for?

[Chicago Storm]

Differences in the NW and SE solutions continues to revolve around the lead wave moving across Canada Tue/Wed and also a wave that stalls over the Northern Rockies and the eventual progression of it.

All of the above is fully onshore and sampled.


.

[Chicago Storm]

What do you look for on a forecast sounding to identify thundersnow potential? I see the NAM has mid level lapse rates in excess of 7C/km and MUCAPE values over 100J/kg in areas receiving frozen precip. There is a lot of shear as well. Is there anything else to be looking for?

Indeed there are solid lapse rates shown and elevated cape correctly positioned as well. Another thing you like to see are high omega values, especially located within the snow growth zone for efficient snow production as well.

There’s a nice overlap in this case.


.

[cyclone77]

No way I'm buying that GFS run, or the runs before it.  If it were on to something you'd think the GEM would have started bumping northward quite significantly by now.  Like others have pointed out it'll prob be a compromise of the north and south camp lining up fairly similar to the last event.  This one has a fairly narrow corridor of heavy accums tho unlike last storm.  Thinking we'll be riding the northwest fringe of this one again unfortunately.  

[Hoosier]

None of the GEFS members are as far south as the Canadian.  Not even one.

[Harry]

I think we should know for sure by the 12z run tomorrow. I know it was around this time ( see GHD lll storm thread 2 ) the GFS pulled the backing off stunt with that event. 

[Sciascia]

I’d love a good snow in Boone County before we hit March & it’s harder to come by as the season winds down.

Kind of a hard storm to properly prepare for in terms of sidewalks. Can’t really throw salt when it’s going to rain first, and there’s not really much time between rain & ice/snow changeover to do anything.

[Stevo6899]

Euro locked in consistently with its track. Another gfs vs euro showdown. 

[Hoosier]

If there was any thought of the 00z Euro shifting north toward the American models, try again.

[Harry]

 

1 minute ago, Stevo6899 said:

Euro locked in consistently with its track. Another gfs vs euro showdown. 

It's crazy especially for being this close in . 

[vortex]

Just now, Hoosier said:

If there was any thought of the 00z Euro shifting north toward the American models, try again.

Yep.  Holding steady 

[Hoosier]

1 minute ago, Harry said:

 

It's crazy especially for being this close in . 

Don't get much more of a spread than this at 2-3 days out when the stakes are as high.  Unfortunate scenario for the offices in the zone of highest uncertainty.

[Stevo6899]

3 minutes ago, Hoosier said:

Don't get much more of a spread than this at 2-3 days out when the stakes are as high.  Unfortunate scenario for the offices in the zone of highest uncertainty.

The GFS has been amped and too far Northwest with alot of storms in recent years, including within 72 hrs. I think most offices will lean towards the euro.

[Hoosier]

Somebody ought to post a side by side of the Euro and GFS snow maps for the lolz.

[Radtechwxman]

I mean you got to take a blend at this point. But the difference right now days out is laughable. Really thought the sampling would help. 

[Hoosier]

2 minutes ago, Stevo6899 said:

The GFS has been amped and too far Northwest with alot of storms in recent years, including within 72 hrs. I think most offices will lean towards the euro.

That's a little risky imo, especially given that the EPS has consistently been north of the op Euro.  I feel like the course of least regret would be a compromise of some kind, but not overweighting the op Euro.

[Harry]

1 minute ago, Stevo6899 said:

The GFS has been amped and too far Northwest with alot of storms in recent years, including within 72 hrs. I think most offices will lean towards the euro.

 

Gut tells me GRR will ride the GFS. They tend to ( not always but usually ) follow whatever model ( GFS vs euro situation ) has the highest snowfall over the office and the GFS has that. Not saying if it's right or wrong but that's how they usually roll at this office.