bncho

It's not over until the CFS says it's over.

Here's my two cents. Yes, the storm two days ago featured sleet falling at 13 degrees due to the warm nose at ~750-800mb. Snow formed high up in the atmosphere and fell out of it, but when those falling snowflakes ran into that warm nose, they melted and turned into raindrops. After they exited that warm nose, they eventually refroze into sleet pellets. I'm actually not entirely sure how a snowflake forms, but what I do know is that snowfall efficiency is determined by two things: temperature (amount of cold) and lift (which brings in the moisture and determines where snow grows). These two things are linked. Moist air is lifted high up into the atmosphere, and the cold temperature allows moist air to grow onto ice crystals (I think this is called deposition?). We don't want too little cold air where the lift sets up (-5 to -10°C) where snow forms because everything about snow growth is generally slower. The moist air doesn't grow onto the ice crystals quickly enough to turn into snowflakes. This causes a domino effect: ice crystal growth is slower so the "snowflakes" don't have time to really grow before they fall out of the snow growth zone, which also makes it harder for them to stick together, and what you see is usually more needle like. No dendrites. We also don't want too much cold air where the lift sets up (-20 to -25°C) because that'll mean there won't be enough moisture to grow snowflakes efficiently, so you'll see pixie dust. If, however, if lift sets up at the DGZ (-12 to -18°C), for some reason ice crystal formation is quickest (I have no idea why). This leads to bigger snowflakes in a shorter amount of time, which induces dendritic growth, or where snowflakes start clinging together. That's why you see those baseball sized beauties fall from the sky. So generally, where lift sets up is where the snow growth zone sets up. Where lift sets up is where the temperature matters most for snow growth. Afterwards, temps below the snow growth zone shouldn't matter much unless it's above freezing (then we might talk about sleet/freezing rain). Hoped this helps. And if I'm wrong anywhere, let me know!

If it's like this on 12z Wednesday then it's probably cooked, but I want to see how the recon data affects the modeling output.

EPS is a more major tick SE (these ALSO just came out on WxBELL)

EPS-AI tick SE (these just came out on WxBELL, btw)

Upgraded CMC shift SE

Remember that the Euro AI trended south before trending back north for the last storm

Everything is more east on this Euro run

0z Euro AI worse, OTS I have no idea what h5 looks like though

This was the same lead time where everything shifted NW for the storm two days ago. We lost the long flat overrunning look on the 00z runs on Jan 19 and it became evident that we were going to amp up. The CMC was the first to show this.

GEFS much more NW, much better

congrats, richmond!

@AlexD1990 is going to get 30+" on this CMC run

That pink area dropped 19" of snow in 6hrs just a testament to the potential we have

Coastal is more tucked than 12z, it's just a little bit later than 12z as well

that's like telling the sun to be dimmer

The GFS is really trying, will it do it?

Our favorite JV model is running.

When tomorrow will the information from the first set of flights be ingested into the models?

The storm isn't necessarily in NAM range, but all the features that will tell us whether it goes OTS or up the coast will be in place by then, like you said.

d18? #blessed

The cold this week is truly historic and incredibly anomalous, especially considering our warming climate.

Ji is like 50 years old.

Yeah, but the EPS doesn't even come close to 8" of snow, so it's probably the CMC.

The CMC is probably skewing it.