eduggs

The 0z Euro looks a lot like the UKMET.

The GEFS has a single member that takes a UKMET-like track through NYS. The 12 GEPS has 2. And the 18z EPS has 4 or 5 including a few that are more amped than the UKMET.

30+ hours of wintry precip would be fun. Would be a high impact event. Even better if this turns out to be a little less amped than the 0z UK and we can stay all snow.

Flips back to snow on the UK. Wild solution. Can't completely discard it though. Shift that a little less amped and you have a great long-duration event.

Spectacular moisture feed from the Pacific through the Yucatan and then into the Gulf States. A mini-atmospheric river. That's exactly what we want to see pointing at the cold dome in the northeast!

Love the major snowstorm on the CMC for next Thurs. the 29th - lol!

The RGEM is showing a little snow north of NYC on Wed. night. There is virtually no support... maybe a dusting shown on the NAM3km or a few other mesos... so it's probably not real. But sometimes with cold air in place a surprise minor impulse can produce a quick inch here or there.

On the EPS individuals I count 13 misses and 11 big hits out of 50. The rest are light to significant hits. ~25% miss rate is still pretty high. Still plenty of variability.

12:1 is a good first guess for ratios IMO. Interior, mountainous regions get great ratios because they get great lift combined with cold. High ratio snow along the coastal plain is usually confined to snow squalls and heavy banding. Long-duration light-moderate snow might not coincide with enough lift in the snowgrowth zone to get higher ratios. Locking in 15:1 could lead to disappointment.

This looks like a good candidate for ocean enhancement in the favored spots of EMA and SE NJ. Pretty high potential locally if we can avoid the GFS-type solution.

The positive spin is the ECM and ECM-AI are clearly worse aloft at 12z than the previous 2 runs. The phase is "less clean"... and yet they both still produce a major snowstorm. That's encouraging. It suggests outcome resiliency and a buffer against negative trends. The negative spin is that the ECM and ECM-AI were clearly worse aloft at 12z in a direction that, if it continued to trend, would lead to a GFS-like solution.

That would be great if this were a 36 hour forecast. I'm just sensitive to any negative trends because this could disappear quickly if any piece doesn't align. The AIs and ensembles still aren't fully on board.

The 12z ECMWF is a step back from 6z and 0z. The phase is not as clean. It's still a great storm as depicted, just not as favorable as the past 2 runs.

I'm happy it's the GFS showing the miss and not the CMC, ECMWF, or UK. But big snowstorms are uncommon - everything has to go right and usually doesn't. So it's reasonable to be on guard for what might go wrong. Any signs of trending towards the GFS should be concerning if you want a big snow event.

If we trend towards the GFS-family, this could be a non-event. The 12z ECM-AI was actually a step towards that solution aloft, despite what it printed out in terms of QPF. If we get a 6z ECMWF, 12z UK/ICON/CMC event, then this is definitely a NESIS/KU event with significant snow from Richmond to Boston. I'm far from comfortable characterizing reasonable QPF expectations at this point. First I want to get more confidence that the 12 GFS solution is unlikely.

The models and ensemble members that have a better phase are slower with the overrunning arrival and longer in total duration (CMC, UK, 6z ECM-AI). The worse phasing models (GFS, GFS-AI, 12z ECM-AI) are faster to arrive and shorter duration.

The 12z ECM-AI clearly has more wave interference than 6z. Slower ULL ejection and worse phasing. It's not as favorable a solution as last run, which was very good.

Everything is dependent on the height field orientation and evolution. The cold air is in place to the north. There is ample moisture to the south. If the isoheight lines are oriented mostly west to east (zonal) on Sat & Sun from North Texas to North Carolina (e.g., GFS), then this is likely a southeast and mid-Atl snowstorm. If the isoheight lines evolve with more of a north-facing component (meridional), the moisture will track further north. The more meridional the height field, the more QPF we will likely get up in our region. The placement of surface features (highs, lows, precip. field) are a reflection of the mid-and upper-level height field. To get a favorable height field we need the ULL to eject east and a favorably timed northern stream shortwave to partially or fully phase.

Most of the area is over 0.75" liquid on the CMC. ELI and parts of SWCT are over 1". It's much "wetter" than the GEFS mean.

Get the arc of significant overrunning to OH and PA inside 84 hours on the CMC, AIGFS, and EPS-AI, and I'll be a believer in a big event. Until then I'm on guard for wave interference and a non-ejecting ULL.

Good signs: - Relatively stable solutions run-to-run on the UKMET and CMC. - 12z ICON adjusted towards the ECM/UK/CMC solution - Storm evolution has trended towards a longer duration event in recent cycles - EPS, EPS-ICON, GEPS have trended north with QPF in recent cycles Not great signs: - The AIGFS has moved away from a big storm idea over the past few days - 12z GFS reversed a multi-cycle positive trend with a sudden shift towards wave-interference - EPS, GEPS still relatively dry (though that's typical considering ensemble spread at this lead time)

But worse than and south of 6z. Not terrible but still room for improvement.

The CMC would be the best storm for most in many many years. It has literally all the ingredients that we love: cold temperatures, all-snow, long duration, includes part of weekend, high QPF. Anyone saying it's not a big storm is crazy. It might not drop record snow anywhere/everywhere, but in a few spots that could rival the big ones even as depicted.

I gotta admit, the GFS/AIGFS make me nervous. That ULL in the Southwest has to eject. AND it needs to be well timed with northern stream shortwaves dropping south through MT and the Dakotas. There are always failure modes.

UKMET looks sweet so far at first glance too. Same trends as other models. I didn't look closely yet. Hope I'm not wrong.