OceanStWx

Clicking around some GFS soundings there are decent lapse rates over the interior just above the DGZ, even absent a MAUL. It would take much to really make the most of that.

We're right on track for another bump or two NW followed by the messenger shuffle late to leave us right about where we are now. I see that poking in from RI.

Well he does look south to the Whites. That would confuse me too.

Taking a look at the forecast soundings the snow growth zone is rather low in the atmosphere. I don't think that changes substantially even with a further north track. So if your above H7 lift is good it's actually not in the heart of the DGZ like it normally is.

We're all friends until go time is just 24 hours away. As for anyone living east of the canal...

It's nice to see what you, Bob, and Dave think. Kind of like forecast consensus. Not going to hurt my waistline any. We legal. To me it seems like the NAM has spaced things out a little better as the lead shortwave exits sooner and the trailing one hangs back just a bit.

I miss them too. But the edibles are more cost effective at the moment.

Ekster had this storm so short term could handle the freezing rain.

It's pretty well sampled at this point, or at least won't be better sampled. But the more it digs tonight the better these runs should get.

Yeah, there were some late closures there that were congrats Nova Scotia, but if we can get that going between MTP and CHH it becomes a rosier picture.

Oh we know there's a bias keeping the QPF too close to the low center for one. But even the 12z GFS has a decent banding signal from central LI through BOS despite what it's QPF/snow output shows.

Sorry, should've included a trigger warning for the snow starved.

As an example, here is February 1 of last winter. Northern NJ is showing an EFI around 1, meaning every EPS member was more extreme than the model climate. And with a SOT value of 2, the top 10% of EPS members were also quite extreme. And well...

There's some good news I guess. Based on the 00z EPS, the extreme forecast index is okay for the AEMATT crowd. This index essentially shows how unusual the EPS forecast is based on the last 20 years of the model climate in the 5 weeks centered on the date (the climate built by many model runs, not state of the climate according to the model). Values between 0.5 and 0.8 are unusual, above 0.8 very unusual or extreme. A value of 1 means that every EPS member is more extreme than the model climate. The thing to keep in mind is that significant snowfall, even in the winter, is unusual. Most days it doesn't snow. But there is a signal for some significant impacts possible according to the EPS. Also note that this index doesn't say how extreme. It could be a little more extreme than the model climate, or a lot more extreme. That's where the black lines come into play, that's the shift of tails (SOT). A value of 1 indicates that the 90th percentile of the forecast is one times the distance between the 90th and 99th percentile of the model climate. A value of 10 would be ten times. A SOT appears when at least 10% of EPS members are forecasting an event greater than the model climate extreme. Say the model climate extreme is 6 inches and the difference between the model climate 90th and 99th percentile is 1 inch, with a SOT value somewhere between 0 and 1 (call it 0.5) this 90th percentile forecast would be 6.5 inches. Notice how the SOT values are higher and the EFI higher down around DC. That's because snow is more extreme in that area than New England, and more likely to be an extreme event based on forecasts.

Okay, now the 00z Euro is the biggest run of our lives.

Sorrey aboot all that snow I dumped on you last run, eh.

It's also a problem that they've been taking 72 hours to get here from PDX. With such flat flow small errors are magnified when things are moving quickly.

The way our grids our broken up this is Thursday night. The nights run 6 pm to 6 am. So 4 am technically sneaks into Thursday night.

It's a numbers game. If BOS pulls 3" a week in the heart of winter it's virtually impossible for them to have a below average snowfall season.

00z clusters sort of flipped from 24 hours ago. It was a 55/45 splits OTS vs tucked, and now that's 46/54. Members that liked the tucked clusters included 65% of CMC (), 55% of GEFS, and 48% of EPS. But that still just means that on the whole the ensemble suites remain pretty split on which way to go. The good thing is that the agreement between members that produce more QPF than the mean and those that don't. The flatter the flow the more like it is to scrape and scoot. Pump the downstream ridging a little and deepen the trof and the QPF is higher than the mean.

Heights across the Puget Sound area look pretty close to reality with the 12z GFS.

That aspect of the pattern is a limiting factor for sure. But if you can get a real dynamic deepening in our backyard it will want to cut across thickness lines and every hour counts.