csnavywx

It does on the GFS, which tells me (regardless of whether this is correct verbatim), that we may not be done with meaningful adjustments there.

Eesh.

Despite the look at the surface, we got some incremental improvement aloft. The phase was sloppier. Northern vort is not digging in one piece now. Cutter primary was weaker. Incrementally cooler upstairs (above 850). Saw same kind of improvement as the 18Z NAM, GFS and (early on) with the Ukie.

18Z GFS is exactly the kind of scenario we need. Screw up that phase and prevent the cut.

The profiles are still active on IA state's Bufkit Warehouse and PSU website.

Yeah, though the closer you are to the mountains, the deeper the cold wedge is likely to be. Once we get close enough I can start posting some BUFKIT profiles for folks that want them.

Yeah, pushed the forecast out earlier than we normally do to highlight the potential here. Proper ice storms are rare in these parts and very little of this vegetation has been "tested" in the past 30+ years, so anything over 0.6-0.7 is going to start breaking stuff very quickly.

You aren't joking. Surface temps in the low-mid 20s with 0.1"/hr+ accretion rates will be a big problem in a hurry.

Trending towards a flatter orientation of the thickness gradient ahead of it with cold air damming setting up faster. Small but meaningful trend. The flatter, the better. Will help inhibit the strength of the surface reflection/low of the trailing upper trough and favor coastal development a little more. It would be even better if we could continue to get that trailing N/S wave to slow down and eject the Baja low a little faster instead of fully phasing with it. Anything to inhibit the development of the inland low and favor the coastal, basically.

RRFS-A coming into range and has basically the same evolution. Slower/less perfect interaction between 00 and 06Z and a bit stronger with the eastern lobe of the high. Interested to see if this becomes a trend given that both trailing N/S waves have yet to become their own entities.

The northern stream is going to be problematic. The one time we actually don't want a triple-phaser. In this case, too early to get cute about where the mix line sets up, namely because both the kicker and the main trailing N/S shortwaves are still over the Russia and the Arctic Ocean and haven't yet become their own entities. My guess is we're going to get flung around for a while. Good news is anything but the perfect phase on the 00Z euro and ukie should result in a retreat south with time. Saw a bit of that on the 06Z Euro. A retreat or slowing of the primary N/S beyond what has already been modeled should result in an increasingly positive tilted trough that comes out more piecemeal than perfect.

Agreed on the big dog. We're waiting until the 12Z runs tomorrow at the office. Should have the main players mostly nailed down at that point. I'm personally kinda split between a solid 12-16" or a 9-13" w/some trailing mix.

More like orange at this point. All systems go for red tomorrow if this holds.

The floor is rising. 18Z runs are no longer slowing down the southern stream and we have some buffer room if it decides to come more north. GFS is no longer the odd man out. I do expect the NBM means to peak right around now as some of the extreme tails get clipped (and there aren't that many duds left to fill in). So don't be surprised if that comes down a hair. Should be able to do a first guess map by tomorrow at this rate.

AI-GFS considerably north of 12Z run. ~0.8 QPF for DC; ~1.1 for SoMD.

Yes.

Short range errors on the southern stream cutoff are still pretty damn high. Still have a full day until that thing cuts off under the ridge, so we may not be rid of trends related to it until that occurs (tomorrow's 12Z runs, in other words).

Getting sold on at least a very solid front-end thump. I had some concerns with the slowing trend in the southern stream. 6Z GFS finally flipping away from holding the cutoff back makes me think that failure mode is sliding off the table. It was an outlier ofc, but if even the outlier is moving away from that scenario, it makes it less of a threat. The TPV has trended slow enough that the eastern lobe of that cAk high pressure will be solidly in place to prevent the incipient low from moving west of the mountains. So the question is now how clean of a coastal transfer we get and how far north that occurs. A phase between the cutoff and the trailing N/S wave would cause the WCB/warm nose to advance further north and perhaps cut into totals here. A partial phase or a simple kick probably still doesn't. But something to look out for on the latter part of the storm.

Depends on how the trailing northern stream vort goes. A phase there makes it more likely. But, usually, in order to get the biggest totals, you need to smell the sleet.

Good thing about the 6Z GFS coming into line is that this lessens the risk from the southern stream/cutoff. It was consistently the slowest and most guidance has trended slower and stronger with it over time. Gives some confidence in it not getting stuck or coming out too piecemeal. We have other potential issues, like interaction with the trailing NS wave, but the big failure modes are getting crossed off first.

Still want one more day of runs before I start barking. Time enough to let the SW cutoff and northern stream settle down.

If we're doing verbatim, quite a bit of mixing on the southern half of the 12Z run whereas virtually none on the 18Z and surface temps in the teens and low 20s. Anywhere near 1" of liquid in those conditions is gold.

Remember to use "max temp in profile" maps where possible or take a look at 700mb even if the 850mb-SFC maps are all below freezing. Warm nose can get pretty elevated in these scenarios.

The one nitpick I have is that the lead TPV lobe is slowing over time, strengthening the eastern lobe of the Arctic high. If it were sliding nicely off the coast, I'd agree more with him. Probably aborts the cut and forces a transfer earlier than the 06Z AIFS. The 12Z runs came back down to earth a bit.

Normally we lose out in these CAD-type storms. This one looking different. Northern stream looks strong and suppressive and the subtropical jet is finally coming back from the dead.