psuhoffman

Question, if you like digital snow more then real how come you complain so much when guidance takes it away at the last minute. Seems it served its purpose already at that point.

A general pattern observation...most guidance has a similar pattern evolution the next 2 weeks. This initial block is centered south of Greenland into northern Quebec. That’s a bit “extra”. It weakens around day 5 then reorganizes in the next heat flux more towards central Greenland to Baffin. That’s a more ideal location. The window would be during the relax then again after that block reforms further north.

Fwiw Icon at 120 looks like the euro and is amplifying the trough in the Miss Valley

My gut does feel like in the end if this phases rain is a bigger risk then suppressed. The blocking is relaxed there and not nearly as much confluence. Luckily the ridge/trough axis looks really good though and the antecedent airmass is decent. Still not good for January but not the rotting dumpster fire it’s been.

so long as we're still chasing ghosts at 180 hours away who cares...but once things start to get "real" and we have a real storm thread that's when we need him to behave

You're looking at the wrong thing for "support" at that range. This looks VERY supportive.

Giddy up

There is much less of a suppressive flow in the way of that wave. But it’s also more complicated then the fairly simple bowling bowl system this week. Need multiple parts to phase. If they do it will come north though. It’s always something lol.

I’ve kinda felt it was forked when all the guidance shifted the H5 track from across VA to across NC a while ago. The N trend we often observe the final 72 hours is not typically from a huge shift in the major synoptic features like the h5 track. It’s mostly due to the fact that globals tend to underestimate the north extent of mid level warm air intrusion and thus they also underestimate the NW expanse of moisture transport and WAA lift in the commahead. They tend to expand that significantly in the end and that mid level warm intrusion also shifts the mix area north. But this isn’t the right setup for that without any deep cold around. There is “some” typical last minute latitude gain of the surface low but it’s not usually that significant. Based on these observed model biases our sweet spot at 72-144 hours out is to have the heavy snow centered just south of us. Like central VA and lighter snows up into our area. Something where a 50 mile shift matters. Once we start seeing the action shift into NC inside 144 hours it’s usually over recently. That’s felt like the way these play out the last decade or so.

I do think suppression is a legit risk until we see the blocking relax some. It’s a beast and centered pretty far south. That panel at the end of the GFS with a closed Rex block centered over Baffin is more where we want a strong block configured and located. That big elongated w-e block centered all the way down into Quebec could set up a shred factory flow over the US for a while. It won’t last forever though and as it relaxes we have a window and if it does reform further north we could have an extended window later.

GFS op recycles the blocking...this second iteration is actually more ideally located and configured. It’s fantasy land but I do agree with the idea the blocking likely recycles several times before breaking down.

There is always that risk in a blocking regime but you have to remember we are too far south for most patterns to work. Absent blocking to suppress the flow we are usually south of the storm track. But take Friday for example. The issue is the blocking is a bit too strong and centered too far south. The ensuing trough in the east gets centered south of ideal. You can see on the means this week the west to east “blue” is a bit south of that “big snow” plot I posted. But if the track was further north we would be just fine. The few runs that did show snow for us were mostly west to east systems too...just they came west to east just under us instead of way down in the Deep South. But it’s unlikely the blocking stays at the current really ridiculous levels. It will wax and wane and during those relaxations we could get a system to gain a bit more latitude or come west to east at a higher latitude. Take that storm that fringed us on the long range GFS last night. That gained no latitude at all. It moved straight west to east but if it comes across 50 miles more north we get a HECS. PD2 was like that. It moved straight w-e until it hit the coast then gained some latitude but not much. PD1 1979 also. We also could get a storm that gains some latitude with a temporary relax that won’t show on a 7 day mean. The slight one day ridging ahead of the storm is washed out on means by the N flow behind the storm. We don’t need a lot of latitude gain. Our ideal track is a primary to TN then jump to NC coast and a latitude gain to about Ocean City. From there ideally we want it to move east. That said the building positively tilted western PNA EPO ridge later in the period does add more threat of suppression. January 1977 featured that look and it was arctic cold but bone dry. That’s going to flood cold into the CONUS and suppress the baroclinic zone way south. So yea that’s a threat. But now I’m honestly getting frustrated and here is why. A week ago when the blocking showed but there was still a N PAC trough and not a lot of PNA and no EPO all the debs were saying “but it’s not cold enough in that look we would need a perfect track”. And now that the EPO/PNA ridge goes up it’s “but that could be suppressive”. Ok well what do you freaking want? Those two things are mutually exclusive. You have to dance with one of those devils. Our HECS look actually has less PNA EPO for the very reason you just said. But it’s not a cold pattern and sometimes it’s not cold enough and we get a perfect track cold rain. The epo ridge -NAO is a cold pattern but dryer and sometimes we don’t get any big juiced up coastals. No pattern is 100% fool proof guaranteed to snow.

Fringed. Major super Uber fringed

Ggem ejects it and is setting up something just past day 10.

Uber long range GFS buries the energy out west. We need that to eject otherwise it’s all NS miller b city.

48 hours before the Jan 2019 storm it looked like 2-4” and you got about a foot. It happens.

It’s 162 hours out. Trends and generalities are all that matter.

But we don’t “keep striking out” this is still just the first storm threat in the pattern. It just feels like it because we waited forever and now you keep treating every model run like a “new threat” and feeling like a while new miss when it doesn’t get better when in reality it’s just the same storm you keep torturing yourself over every 6 hours! The Jan 12 storm is still out of range but trended better fwiw. I think that has a better shot but in sticking with my original call from a week ago that the 15-20 and maybe even after is our most likely window to score.

We need the blocking to relax some...even there the “wall” in the flow is a bit too far south. If that backs off just a wee bit that’s a hit. Was a great setup for a moderate snow otherwise. This is just speculation based on current guidance pattern progression and history but all guidance has a weakening of the blocking around day 10 before strengthening it again toward day 15. That might be our best window around Jan 15 before maybe another after the next NAO flux.

The block is centered too far south...creates a shred factory and the system starts to wash out and gets absorbed into the trapped vortex to our northeast. Literally too much of a good thing. Little better antecedent cold and it would be a good setup for NC. You know this...and I know it’s hard to wait...but we typically score AFTER blocking tanks and is relaxing. This is one of the reasons why.

Over the past 5 years or so I’ve observed often guidance shifts south with east coast storms in the 3-7 day range before shifting north again slightly the final 72 hours. But the north shift isn’t this huge hundreds of miles one like in the 90s and 2000s. We want this to get a little closer then it currently is by the 72 hour threshold to have a legit chance. Still time. Navgem is interesting but it’s way off the consensus on a few things. It’s weaker with the 50/50 and washes that northern SW out completely so there is no pinwheel effect holding the 50/50 in and it escapes in time allowing the storm to climb the coast. It’s also a lot weaker with the southern cutoff and has higher heights all across the east too which is why it’s a warmer solution.

But does it remind you of something???

You mean the flow into the Atlantic? We are upwind not down. They are packed tighter because that’s where the mean storm track is and so you get a tighter thermal zone there. They are more w-e because of the block. Storms cannot gain much latitude under that. And that’s what we want. A minor gain in lat like say from NC to MD before turning east is what we want but that will get washed out on a 7 day mean. Look at the mean for our best snow years. It’s the same feature. A W-E oriented trough from the mid Atlantic across the Atlantic Ocean. That’s a blocked signature. Storms cannot lift poleward because of the block end are forced east.

This... which isn’t terrible for a week 4 prog except it’s pretty much a carbon copy of week 4 all cold season. Mid November this is what it thought the week mid Dec we missed one snow to the south and another hit our northern 1/3 would look like And 3 weeks ago this is what it thought this next week were now worried about suppression from a big eastern trough would look like... And 2 weeks ago it had this for the week around the 15th that looks great on Eps now seems like a familiar theme from a month out on the weeklies...

Euro weeklies, gefs extended, CFS have all been doing that past week 3/4 since November. But it never moves closer in time. This is all anecdotal but the last several years it seems that once you get past week 4 on long range guidance it consistently tries to revert the pattern to whatever makes sense based on what guidance thinks is the dominant forcing mechanism. Last year it correctly identified the MC tropical forcing and the +++AO and so it did very well. In other years when it misidentified what was the dominant drivers it continually head faked a mirage pattern change. This year feels more like the latter based on early returns.