psuhoffman

Long shot but there could be a wave on the front around the 16th

I was a meteorology major at PSU for 3 years. But in the end I dropped the meteorology in favor of sociology and later decided to go into teaching and coaching in the inner city. I did get a good foundation from my classes at PSU. I had a class with Jon Neese who was later on TWC. I think I used to annoy the crap out of him in the weather station. But honestly I learned 90% from experience and doing my own research and reading. I’m the weirdo who reads a textbook just because I want to understand something.

You can’t see it directly there but you can see the evidence because there is a 1004 surface low with h5 low ejecting so obviously it has an associated SW and vort. It’s just assumed from secondary evidence.

A low transfers when it meets resistance and can no longer progress and reforms somewhere else along the thermal boundary. This can happen because of the upper level support jumping or a surface feature blocking progress. Often the jump we want is a system moving northeast up the west of the Apps to jump to the coast. What typically causes this is when a cold high is blocked in to the north impeding the low, and CAD banked in against the mountains so the path of least resistance is to jump east to the baroclinic zone along the coast. The example from the 18z gfs is below. the primary in the Midwest has hit a brick wall of confluence. Note that system to its north hit the same wall and has actually done a loop and is retrograding west because it’s an arctic wave removed from any thermal gradient so it had nowhere to jump too. It simply put er in reverse lol. That primary in IN can’t go anywhere. So it’s going to transfer to the triple point along the front in the Carolinas. That’s common because there is often a lot of lift there that can promote pressure falls and an enhanced baroclinic boundary. It’s also along the warm front providing a path east under the block for the storm to progress so it transfers the energy there.

A storm in 1972 transferred from the UP of MI to SC. That was probably the most extreme example.

Recently no. Are there examples of that in the past yes. It takes a blocking regime and a cold airmass.

Just a little blocking when storms transfer from Indianapolis to Hatteras

I think, as wxusaf, that it’s a bit of both bad luck and the background stage becoming incrementally more hostile. In December we had a nice AO ridge but it was a bit north of perfect. That can work though if you get other things to line up and we almost did but that SW that dive in out west really screwed us by amplifying the trough more. But it’s hard to get a big snow in mid December. The first iteration of the -NAO this month ended up too extreme imo. That was part of the problem. I posted this from a couple days ago. That ridge is centered way too far south and extends too far SW. Not only did that suppress 3 waves but it prevents colder air from draining into the pattern to the west of the block. Center that further north without that extension into Quebec and we get a slightly colder profile and less suppressed systems and I bet one of them “works out”. This next flex of the blocking looks more ideal but now there are questions about what kind of PAC we get. Ideally I would have liked one more bite of the apple with the current pac and a better NAO. But I don’t have the magic crayon. And the look we see now is pretty darn good. And I’m biased by my location. If I were you I would definitely go with the colder but possibly dryer option. We have way different climo.

It just depends. Not all blocking patterns are the same. But a -NAO split flow isn’t uncommon and usually a good thing. It’s not a cold pattern. Feb 2010 was one. The Polar jet was directed across Canada by the trough in the pac but the southern stream was splitting into the SW and coming across the gulf coast. But the pac jet wasn’t as intense and the profile in Canada wasn’t as awful to start. But it wasn’t cold. Actually north of us was very mild. And even here it would have been 45 that week had there not been snow. It’s a pick your poison thing. A split flow cuts off the polar air but normally in winter we can develop a just cold enough airmass under the flow to get snow with a good track. This year that didn’t work out. A -EPO -NAO non split flow is much colder but it can be a dryer pattern if storms dive in too far north to amplify under us and the STJ is cut off in that case. So there are pros and cons to both. FWIW the split flow option accounts for a lot of our HECS storms.

Blocking patterns aren’t always cold. Often they are quite mild north of the storm track. This year has been to the extreme though.

Shockingly this would make the 3rd time this cold season the EPS caved to the GEFS wrt long range longwave pattern. The op GFS has been awful with synoptic details in the medium range lately but the GEFS since it’s major upgrade has been extremely good with pattern recognition.

Not that uncommon for a high lat blocking pattern. What’s uncommon is there wasn’t the snowy response further south. There was the response in the storm track but it was just rainstorm after rainstorm.

Keep it up and we’ll be shoveling something...

I like the end of the EPS run. That NAO/50/50 configuration is ideal. I couldn’t draw it up better. Would make it really hard for anything to cut. Yes the main trough is west but the SE ridge is suppressed and flat and enough cold should bleed east under the block in that look. That trough will also help eject energy that can slide under the blocking Look at the temperature and pressure profile Thats really good. The gradient is to our south but it’s not suppressive and the polar boundary is just to our north. Plenty of cold to tap. The mean SLP is screaming this kind of result imo!

I actually like the end and about to show why.

Yes..took a step back from the ledge. Also better NAO block and that wasn’t even a problem to begin with.

I think the EPS took a baby step towards a better look for the threat window around the 20th much better ridging into the west and more depth to the eastern trough as well as a better alignment. Only snag is it still washes the wave in front of it out and so the WAR is still there. If that wave can amplify into a 50/50 that’s a really good look. But 2/3 factors moved in the right direction. Meatloaf approves.

It’s a beast signature and centered almost perfect across all guidance. But if that degrades we’re screwed no matter what happens w EPo given how far west the pac ridge is.

Definitely but I guess that part I just took for granted since the -NAO is there across all guidance. The difference is the GEPS/EPS lost the EPO ridge and develops a flat pac ridge.

Yes. It all comes down to that. The GEPS is fully on the EPS side now. Both lose the EPO ridge and the pac jet gets directed right into the CONUS. It’s all down to that one feature because everything else is identical across guidance (except for features that are a direct effect of that difference).

I mean worst case people post in the wrong thread and so it’s the same as now lol. I think people can figure it out. Don’t disappoint me people.

Just in case anyone wasn’t in on the joke the gefs didn’t cave. Even out to day 16 it was pretty similar if not slightly better then the 0/6z runs. Model death match still on.

I’ll wait

@frd @CAPE @WxUSAF there is a dichotomy long range. The strat crew keeps hinting Feb could rock. The MJO/AAM/GLAM gang thinks we torch feb. There are conflicting signals. The progression of the tropical forcing and angular momentum favors a warmer canonical Nina Feb. The SSW progression favors Feb as when we see the greatest impacts on the TPV and subsequent blocking and cold intrusion into the mid latitudes. The question is which driver wins that fight or if it’s a stalemate does that end up favorable enough for us?