high risk

One other thing to note is that the para gives more weight to the CAMs in the short range, so it will be really fun to see what this event looks like as get closer to it happening.

Not fully true. While the time it starts doesn't match the operational, the actual cycles of the parallel use inputs from the same model cycles as the ops. Worth noting that the ops does not include any Canadian inputs in the winter suite, while the parallel uses several. And a reminder for everyone: both the ops and para winter products only update at 01/07/13/19z.

It's not "new" per se; it's just faster on both the GFS and AIGFS.

Nope. The winter stuff updates at 01/07/13/19z.

First, remember that the GEFS is now 31 members. I think there were dissemination limitations that prevent all members from being sent to various servers, but the 20 displayed in that image are only a subset. That said, there are certainly a bunch of GEFS members that are duds, but my guess is that those are the ones that keep the cutoff stuck in the far Southwest. Certainly limited support for that idea outside of the GFS/GEFS camp.

Doesn't really change the final result, the ECAIFS is notably slower with the arrival of the event on Saturday.

Yeah, it's not the biggest deal that this forum attributes late-arriving graphics on a downstream website to "the model is running late", but it ain't a bus stuck in traffic. These models run at the exact same time each day, and it takes close to the same amount of time each cycle for them to run. > 99% of delays are dissemination issues or issues at the sites generating graphics. The model itself is only late if it crashes or there are huge computer issues, both are which are exceedingly rare.

GEFS spaghetti shows that while some members do leave the trough behind in the Southwest, a lot of the members eject it eastward.

So, the question was whether the AI systems retain info cycle to cycle. They're independent cycles. One word of caution for everyone who is excited to see so many hits in the AI ensembles: the AI ensembles are very underdispersive on the whole, and this will be an area of research going forward. I would therefore advise caution when they show high probabilities of an event, as they can show high confidence in the wrong outcome.

FWIW, the AIGFS and ECAIFS runs this morning have some remarkable similarities in the Eastern U.S. for next Sunday, with a high-impact winter storm, even impacting our area. These two AI systems have been bouncing around a lot, so appropriate caution is warranted, but them both agreeing today catches my eye.

A round of snow later this afternoon for those east of DC is definitely not off the table. Even runs late Saturday showed a second round later Sunday afternoon - they just disagreed on how far west it would come. And there still isn't a ton of agreement on that......

One thing to watch for later today: The NAM and RGEM end the event by mid or late morning for everyone west of the Bay, while the GFS and some HRRR cycles have precip ending by late morning but then bring another round of snow for DC and points east later in the afternoon.

Seriously. I'm baffled by he expectation that we should lock in a solution at 240 hours and have every consecutive deterministic cycle not waiver in the slightest.

Northern Maryland won't get as warm in the low levels, so verbatim from the 18Z NAM, they're ok for snow. But areas south of I-70 have ugly soundings: That's rain for sure, and it occurs at a time when precip rates are really good. The 18Z HRRR looks the same. We have to hope that this is incorrect, and given the lack of run-to-run consistency, that isn't necessarily just wishful thinking.

About 1-1.5" for the Howard County crew with more along the Bay and a decent bit more for the Eastern Shore.

The recent AIGFS cycles have more of the longer-range consistency (and overall favorable pattern look) that y'all are craving.

I agree. Any pattern that generally prevents "clean" southern stream waves is going to have limited predictability in the medium range.

Yes, especially for the Euro ensembles which arrive so much later than the GEFS and GEPS.

I know that there is a lot of frustration in this thread, and I completely get it, but the "the models suck way more than they used to crowd" (and it's only a few people) really needs to go take a deep breath. Attached are two 500mb GFS forecasts for the same valid time, made 12 hours apart. On the hemispheric scale, they're pretty freaking similar. Unfortunately, there are some minor differences with the handling of the eastern trough, at least partially driven the trailing wave over the upper Midwest. And UGH - those differences are enough to change the track of the east coast low by about 150 miles, and the resulting impact on the band of significant weather is the difference between us having 4" of snow or a partly cloudy day. We all want these perfect fat and wet southern stream systems that we can easily track for days with minimal stress, but the reality is that northern stream systems are dicey as hell. They're small, and they're initialized in data sparse regions. I looked at the two features that will drive the Sunday "event", and the lead wave yesterday broke off of a vortex in central Canada, and I could barely trace the trailing wave back to the polar regions. The small changes in the handling of those features unfortunately cause major changes in the outcome for us. And it should be noted while not every modeling system has shown a good event here Sunday with that trough, they have all bounced around a lot with those two waves and the resulting impact on east coast low formation and associated precip stripe. That speaks to the incredible challenges of complicated northern stream evolution. There is where ensembles help a lot, but we really need to move away from using means (at least inside of Day 5) and focus more on exceedance probabilities, because a handful of snowy solutions among a large number of dry ones can really influence the mean value. Let's hope that we get buried before Valentine's Day so that any further complicated Miller Bs don't cause the chaos in this forum that this one has.

The deterministic NBM snow product does indeed weight the meso models more, but that's too far out to include them. Even the SREF wasn't in range. I looked at the forecast in question, and the amount of forecasted snow was only around 1.5", but it was largely driven by some very snowy GEFS members. Of note, the winter products in the NBM update at 01, 07, 13, and 19Z. The 19Z products will include the 12Z GFS but NOT the 12Z ECMWF (which hasn't yet arrived by the time that the NBM winter suite is run).

Are these dates off by 1?

Temps just above freezing, but it's night, so maybe stickage on a few surfaces? That said, the CAM suite consensus is for just a little bit of snow at the end, with the area of snow expanding after crossing the Bay. One thing to watch for all of us is that any wet spots could freeze early Thursday as temps drop quickly behind the front.

I think that this is very much on the right track. If you look at the 10m wind field, the expected intense circulation on the east side of the storm just isn't there. The 850 wind field looks like garbage too.

I'm still very interested in tomorrow, but the simulated reflectivities all suggest very scattered activity. Should be fun for those who get under one of those heavy showers, and we'll need that intense omega-driven cooling to combat fairly warm low levels. The simulated reflectivities show rain except for right under the most intense cores.

It definitely looked in forecasts from early this week that today would be a taste of spring, but that idea disappeared by midweek.