Terpeast

ICON is not even north. Just a few hours slower.

I think LWX is smart to call out potential for sleet/freezing rain because that will have bigger impacts on the Monday morning commute than an all snow event. Anytime we're flirting with the mix/changeover line, it has to be addressed and made known to the public.

I want to caution that this is just one run, and as a reminder, this is a global model that may not have the best resolution for working out the ptype details per soundings. The mesos will help us with that starting tomorrow afternoon-ish. If this holds, should be "mostly" snow for the DC/Balt metros.

might see some mixing when rates decrease upon dry slot, but that's really nbd

GFS soundings at both IAD and DCA show a nose between 750-825mb just touching 0 C. This should stay snow verbatim

Looks like a thump to mix to dry slot verbatim. Hard to tell between 90 and 96 hr

Looks more like it closes off over Indiana, but with flatter ridging ahead under confluence that seems stronger and more south?

a stronger s/w (shortwave) with more confluence would create a stronger CAD situation, imho

I like this. Gives the DC metro a bit of wiggle room

Temps likely run a bit warm, but I’d be paying more attention to timing due to the friday PM commute

Nice to see the euro take a step back south, and the gfs is mostly a hold if not a tick north. Let’s see if they tighten up the goalposts. If the storm start time is sunday night, it’s 3.5 days away now. That’s usually the time when models start flushing out any major disagreements with each other, barring a last minute trend.

Love the CAD on the CMC. Sign me up. IAD sounding show a warm nose at 800-825 mb flirting dangerously close to 0C, but stays colder than that. Too early for these details ofc

Ha, not that easy using pivotal on mobile. Fat fingered it

Never mind, Was on a different model page when comparing. Disregard. Sorry.

At 500 it is, but the surface is different

Looks similar to todays 12z gfs

Looks similar to yesterday’s 0z

And confluence actually stronger…!?

84h, closed low about to go neg tilt

Also a bit slower

66. S/w stronger, confluence same, NA vortex a touch west

Verbatim light snow to sleet/ice then dry slot for DC metro

Yep

NAM stronger s/w, but confluence also presses more SW. probably offset each other to some extent Not that this is worth much at this NAM’s range

Now that 18z euro is on TT, I looked at the N Atl vortex and the s/w. Those aren’t huge shifts between 12z and 18z at 500mb. The confluence is still there, but slightly weaker and more east. The s/w is a few dm stronger, but still with a neutral tilt. But the surface difference is dramatic. I do wonder if the Euro is overcorrecting at the surface and blip back a bit south (it won’t go as far south as gfs or icon). In addition, these shifts are typical at 500mb 4-5 days out, and we don’t usually notice these when they are cutters and rainstorms. just my 2 cents