AppsRunner

Didn't see it mentioned but the GFS was basically a drier, slightly south version of the NAM.

There are some incredibly large precipitation ranges between the CAMS across most of Iowa for a 36 hour precip forecast. I've seen ranges anywhere from a couple tenths to close to 3/4" of QPF.

DMX issues a warning for most if not all of the CWA. 6-10" expected.

Even with those issues it still has what is likely warning criteria snowfall across a good portion of N IL outside that snow dome.

It's their whole CWA. DMX is considering a warning... potentially a warning for the north and south with an advisory in between.... or a blanket warning. Should be a decision within a couple hours.

The 12z RGEM has a 999mb low over Paducah at hour 48. A little bit further north with slightly better phasing than the NAM.

While the surface low track is pretty similar, there are some large differences in the precip field, especially in IA/IL/MI where the main WAA snows are displaced north with a general decrease in amounts with the slightly faster progression. This is a really good run for N IL though.

Not any huge shifts one way or another (at least at the surface), but a hair quicker aloft. Close to a neutral tilt by 51hr.

That NAM run is the best case scenario here. Take that and run please

Significantly more QPF on the 21z SREF around here. QPFs approaching 0.60”

A lot of guidance was fairly dry prior to the 18z runs. The grids have 4-6” now, don’t have a problem with that.

It’s going to give someone in Iowa warning criteria snows but where it does is another question. Should provide a healthy snowfall further east too even if we don’t get the other players to cooperate

GFS is a pretty good look N MO/S IA into Illinois. Canadian much weaker but still some light snows.

Always have liked these GEM 4panel plots. The northern s/w isn't as good as before but still not bad. Pretty good widespread hit with some higher end snows for OH.

12z NAM actually reminds me of the GFS runs from a few days ago, with no huge numbers along I-80 in IA/IL/IN but respectable totals with decent ratios. Would take that and run.

18z GEFS is just a hair further north/west of the 12z. Looks like most members are in fairly good agreement with some oddballs in there too.

Ensembles are very similar to last night. Very tight clustering of tracks across the Ohio river, will post when I’m home

A couple things to watch for... Inconsistent handling of the northern lobe of energy rounding the vortex over the Hudson. 00z run was much better timed (albeit it did leave some room for improvement) but the 12z this feature is much slower and a little weaker. Trough/main vort max digs a little deeper than previous runs. True in the GFS too. While those things mean that it was a less widespread snow for the western half of the sub on the 12z suite, there still is a good signal for accumulating snow for a large fraction of people here, with big time snow potential still between I-70/80 in IL/IN/OH. Around this time last week the models were significantly south with their placement of QPF, so just be patient. One of the biggest problems with these events is that everyone latches on to the big runs from 7+ days out. Trends in the D4-5 period are normal and that doesn't mean models won't correct back in different directions over time.

When should I post the JMA and NAVGEM? I should probably dig up my old links to the Brazilian and KMA too.

On my loose counts, only about 3 of the 20 members shifted south with a majority ticking just north or holding serve. Mean is basically unchanged if not a slight tick north.

In other news, the UKMET tracks from SW AR to N GA to off the coast. Don't have the precip maps but

FV3 is definitely south. 12z GEM looks like a really nice storm for Buckeyeland but I don't have the zoomed in charts just yet.

A few soundings along I-80 show a rather deep DGZ and temps in the teens. Probably 20:1 is a touch overdone but somewhere around 13-17:1 seems reasonable.

FV3 in between the GEM/GFS solutions. Doesn't look like a huge hit anywhere west of the Apps.

Feeling about as good as I could in Iowa. Definitely going to need the snow to make the -10s/-20s afterwards at least somewhat bearable. Looking forward to tracking this week.