Stormchaserchuck1

03z SREF

Yeah it's amazing that models can miss things like that at that range, but I've seen it a number of the times in the last few years. N. Hemisphere larger 500mb pattern likely wins again, I was saying to see a deep coastal low riding up from the Gulf we probably need a NE Pacific trough, which is a actually a weak high pressure right now, and goes with what you guys are saying about how hard it is to a MECS in La Nina.. the pattern is actually a +NOI, or +NPH (North Pacific High), which is in part a circulation of La Nina. https://ibb.co/DfGZyQjg https://ibb.co/gLrqM6cz I wouldn't be surprised if Richmond may have p-type issues honestly.

Marginal risk for severe weather tomorrow.

Maybe instead of looking at how it did at 120hrs, see what the storm moving so far North means with regards to the future.. we have a real shot at thunderstorms tomorrow. The warm sector of this storm is awesome! They say swings happen and "nothing is impossible" but the somewhat slight flex of -pna here today is for a flatter, and possibly slightly north, following storm..

All it says is "Haha". No other options.

How do you see who weenies you?

Pretty major severe wx outbreak going on from the Gulf of Mexico to Kentucky. I said this before, It's part of the weak -pna pattern that has a weak High pressure off the west coast. Downstream that leads to a less amplifed wave, moving more W->E vs S->N for Feb 20th.

That "EE" rule has been around for a while.. And we've seen it play out a number of times. Truth is the NAM (ETA) sucks as a model. It has no actual accuracy that is better than other models when with the Euro.. the NAM at 60+ hours is usually more ampled/NW, and that models usually trend this way in general is where the rule comes from. That and the Euro's accuracy.

You should have kept your other post about positive tilt in the gulf.. don't let 1 model run deter you. Especially when the Hemispheric 500mb pattern is not ideal... now we can get an amplified storm under a block, that part is good .. -AO extending down into the Hudson bay, but pieces 2 and 3 (Atlantic and Pacific troughs) are off.. that gives more margin for error and variance in models until the day off.. more of a "threading the needle" situation.

What your missing is that the trough is flatter on models than the Richmond snowstorm composite.. less neg tilted. That's the big difference. It's still likely a snowstorm but not a historical analog. You are thinking it means north, and it may, but really a flatter solution is the bigger thing.

I said it wouldn't be a bomb and would be flatter... reason is there are big differences in the Pacific off the west coast. We have a weak High pressure there, vs east-based-posPNA that a lot of analogs had. That Gulf of Alaska trough digs waves downstream, and you can get a Miller A type system.. that's not the pattern we have for this wave. Little chance it goes back to a bomb/blizzard, unless the Pacific pattern changes.

You're right -- it's 1/4-5, 1980. https://www.glenallenweather.com/upload/richmondclimate/richsnow/GreatestSnows.pdf Here's the fix

Yeah, with the MJO. Scandinavian ridge is building another -NAO bout potentially in the long range, but the +QBO/Weak Nina impact on the Stratosphere has been strong this Winter -- it's been hard to sustain a -AO with such a cold 10mb layer. It's actually been a surprise we've had so many -AO periods, but they generally aren't sustainable with such a fast flow in the upper atmosphere. Fits the seasonal trend of late - we are getting -NAO's, about average to even slightly above average, but they are in continuum less than average.

Warm pattern setting up in the medium-range.. Feb 20 is probably going to be our last wintery threat for a while.

I'll say it again -- I find it interesting that in the Richmond top snowstorm composite, the 500mb trough in the Southeast, US was the 4th strongest 500mb anomaly in the N. Hemisphere. That is so interesting, because it's a 20 day-analog composite of picked-and-choose analogs of Richmond centered snow. So what that tells me is we need those other N. Hemispheric anomalies to really hit. The -NAO extending to the Hudson bay is a big hit -- but the one missing is a <-100dm anomaly off the west coast. At 500mb, there is even a NW, US trough in the Richmond-snowstorm-map! This time we have a slight High pressure off the west coast, meaning that the East Coast trough may not dig as far south, and the wave may be more progressive vs something that really bombs.

After looking at composites of top snowstorms, it's close enough... but you can see that we still don't have a New Foundland Low though.. it's 750 miles away. I just don't think we are going to get a deep/bomb scenario like models are real close to showing. Yeah, the H5 is a little north of Richmond.

I see it as a flatter storm though vs all the deepening that models are showing. It may end up further north, but not as strong riding up the coast. That is because we don't have that deep N. Hemispheric pattern of large waves in the mid latitudes -- extended. It does deepen under the perfectly placed Hudson bay/-NAO ridge though. Historically that +PNA is a big piece to dig th3 southern jet, and phase the northern jet too.. But it's not in a perfect position.

Richmond's 20 greatest snowstorm days since 1948, based on the Feb 20 date. Pretty close to the current projected pattern.. 3 troughs Pacific-US-Atlantic around a -NAO, ridge extending into the Hudson Bay.. That difference off the West coast (ridge vs trough) could be a reason why it will be a flatter storm, vs a more S->N amped one.

Closed 500mb low over Minnesota Low pressure in Gulf of Mexico Crazy potential on the model -- Maybe expect something less extreme in future model runs? N. Hemisphere 500mb pattern is good, but no extreme +PNA or anything like that

15z SREF also looks pretty north

When is the last time we had a >1050mb High in the Midwest for a storm? Seems pretty extreme. The 18z NAM at 84hr has 1054mb. Todays 12z models holding the storm really upped the chances imo. Also, if models weaken that 1050's mb High in future runs, will the storm trend north?

Congrats! It's better to look at 500mb and make your own determination.. a lot of times lately they have called -NAO's, +NAO. There was a 4 year period actually where the H5 over Greenland was +90dm and they had it >+1.00 NAO for the 4 years.. It's ok if SLP disconnected a little, but these are big differences we are talking about! Someone from the NW, US mentioned to me how it was their 4th coldest Jan 15-Feb 15 since 1950.. I was like, in such a +PNA period! Then I looked, and that's not +PNA at all lol.

GFS ensembles make me a little trepidacious.. but they usually mostly follow the OP A few of them show a good hit though.

We get buried on the Euro. I would love this! Another thing too is if we do get a good snowfall, temps should be cool for a while, at least below 40. The upper latitude pattern goes south, but we do hold a trough it looks like for up to 7 days after.

A lot of possibilities on the table. I'd feel better if we had low pressures at the latitude on both sides, closer, a slower mid-latitude flow, but a block over the top can be enough to buckle the flow under it. GEFS did trend stronger with the Canadian block today.. if it times right, we can do a monster. Still a lot of variation though in what could happen imo. You want to see more ensembles showing a hit. Watching closely. It could be a fun storm! Hopefully it holds. I'm not strongly for or against it right now.