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January Medium/Long Range Discussion


WinterWxLuvr
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1 hour ago, WxUSAF said:

Ok, wanted to make a post showing the impact of the ocean storm on ~Friday to the environment afterward and hence the possibility of a Sunday/MLK day storm.  Helpfully, the 3 big globals provided a very nice contrast in this with their 12z runs.  Obviously there are other differences that impact the result as well, but I think the ocean storm is a pretty big player to help define the storm track and whether it gives room to the next shortwave/s to amplify.  

 

First is the 12z GFS.  It produced a very strong ocean storm that was close to shore.  For reference across all 3 models, the shortwave that could produce a late weekend storm is near the US/Canadian border over ND/MN in the northern stream.  There's also southern stream energy over the intermountain West and southern CA.  gfs_z500a_namer_21.thumb.png.045fa352f64a3ec7028e0275869bc4b5.png

 

Next is the GGEM.  It's ocean storm is weaker and farther SE over the ocean.  It's nearly a cutoff low and just meanders out to sea.  gem_z500a_namer_21.thumb.png.1f7e327aa78bb2b98b7bdb3944c7667f.png

 

Lastly is the Euro.  It produces a storm, but it's moving offshore and is "just right" in terms of storm strength.  Strong enough to suppress the flow, but not too strong to swamp everything else.  Helpfully, also note how the northern stream and southern stream energy already is somewhat "phased" here (all the shortwaves are in line from Los Angeles all the way up to Manitoba).  ecmwf_z500a_namer_6.thumb.png.3ba39ec18a31a969df3e1ffcee2e8b50.png

 

So what happens after?  Watch the dark green color, which in this case is the 552 dm height contour, and the light blue (534 dm height).  

GFS:  Look how close the ocean storm is to the surface reflection of our shortwave of interest (the L near Cleveland).  Light blue height level right through the Great Lakes.  The ocean storm hangs around and is very strong.  It suppresses the flow and gives our shortwave no room to amplify.  So we end up with a weak frontal passage.  

gfs_z500_mslp_namer_25.thumb.png.39048c118d0ec1f95b4dfb274ac1c136.png  

 

GGEM:  The storms have more spacing, the ocean low is weaker, and there's TOO MUCH room for our shortwave/storm to amplify.  Dark green height contour is well up into OH/PA/NYC. Result?  Cutter.  

gem_z500_mslp_namer_25.thumb.png.2185aa4ce73b23b60b8f494a6a6c5350.png

 

Euro:  Now it's JUST RIGHT.  The ocean storm is nearly as strong as on the GFS, but it's farther OTS.  So it's suppressing the flow just enough (dark green contour is through VA), but not TOO MUCH.  Hence, our storm tracks farther south and it's bombs away.  And yes, the Euro is also good because it phases the northern and southern stream energy. But the storm track is important.  Phase the energy on the Euro, but have an ocean storm like on the GGEM and the thing cuts to Hudson Bay and we get warm rain.  ecmwf_z500_mslp_namer_7.thumb.png.c50231148fe98715c8b01459b97f267e.png

 

I think the GFS solution of a strong ocean storm that's close to shore is probably the last likely?  18z GFS was a small step toward a more Euro like outcome.  GGEM and Euro like outcomes for the ocean storm are more likely IMO, but that doesn't mean we get a big snowy coastal because that's also contingent on how and if the energy out west phases.  

Thank you…fine write up

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15 minutes ago, clskinsfan said:

Was a pretty common thing with the GFS before the upgrade. We are going to find out if that has been fixed or not over the next couple of weeks. 

did you just put together an WTF QB Draft package video lol?

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11 minutes ago, psuhoffman said:

Just to drive home the luck factor…that loop is beautiful. Absolutely perfect pattern. But look at the result of that run on the ground. 
9C6CEC36-3EF4-44D1-AC7F-DEFD46C1012C.thumb.png.31ee123679d6f73e5ccaf44918849c58.png

know that would be a hell of a guest post by Steve. Thanks for doing that btw!

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13 minutes ago, psuhoffman said:

Just to drive home the luck factor…that loop is beautiful. Absolutely perfect pattern. But look at the result of that run on the ground. 

That is funny. I guess luck needs to be listed first in order of importance above a  - AO , -NAO or a + PNA in the Mid Atlantic. 

Hopefully we get some great luck to go with our upcoming favorable pattern.  

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51 minutes ago, frd said:

That is funny. I guess luck needs to be listed first in order of importance above a  - AO , -NAO or a + PNA in the Mid Atlantic. 

Hopefully we get some great luck to go with our upcoming favorable pattern.  

Your point is correct but those other things (the ways we quantify the pattern) are pre-requisites before luck even matters.  We can luck our way to some minor marginal events without any pattern help but we’re not getting a MECS or HECS or some heater of successive SECS’s without any pattern help no matter what. Sometimes we can score with “less” help but if the NAO, AO, PNA, EPO are all bad luck won’t save us.  The pattern puts us in the game then we need luck to win. 
 

On a related note, there were a handful of warning snows in my case study (BWI warning snows since 1950) without any discernible pattern help in the indexes but they all had a Hudson Bay ridge. That’s a weird feature that doesn’t always show up on any of the numerical indexes yet it’s a more regional feature that can turn an otherwise bad pattern into a workable one. 

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I've done LP comparisons with the OP and Ensembles in the past, but I think it has more weight at this range compared to within 100hrs. There seems to be two camps with the 0z EPS: closer to the coast, and suppressed solutions. The Euro falls in camp two, with this overlay of the OP and Ensemble showcasing that

660376564_ecmwf-ensemble-avg-east-mslp_with_low_locs-2334400(2).thumb.png.467d5c173533a9d94c42dce484201127.png

There's a lot of visual clutter here, but the large L represents the Operational run, put on top of the ensemble. It shows a 2 LP look but the most northeast one seems to be the correct position as this panel is mid transfer. This shows that the Euro op run is in the "suppressed" camp for sure.

Here's the EPS run itself to clear up any confusion with respect to the OP

1122431144_ecmwf-ensemble-avg-east-mslp_with_low_locs-2334400(3).thumb.png.337ee617a6b3441e6535d515d89a5e72.png

This is actually a slight improvement from 12z. The spread is to be expected, but the mean is still showing a significant LP somewhere in the vicinity of offshore NC

1203712489_ecmwf-ensemble-avg-east-mslp_with_low_locs-2334400(4).thumb.png.c31b370c6a10928d5498b131809ac3d4.png

Finally, the look over top improved somewhat compared to 12z. The 50/50 signal shifted a tiny bit west, and the HP position and strength looks as solid as the EPS has shown so far

737359288_ecmwf-ensemble-avg-conus-mslp_anom-2291200(1).thumb.png.7aae2e53c7ce80d483440dad4b1a8849.png

 

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10 hours ago, Ralph Wiggum said:

Dare I say....I kinda miss TWC circa 1987-1995ish. Actual mets, some extremely extremely advanced mets (Stu Ostro, John Hope, Paul Kocin, Dave Schwartz, etc etc). Actually delved into atmospheric sciences and taught and took time to explain and weren't just on camera celebs. I know that outlet tends to get ripped by weenies near and far....but that was a much simpler time and we were at the mercy of the long range forecast they did once or twice an hour. Good stuff. The coverage of the 93 and 96 storms on there....epic.....just epic.  

That 1996 Bliz coverage on TWC was truly EPIC - At least a hundred Bob Chill Faces EPIC! Just Wow! I was up all night, all day.

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Would the 06z ICON be good for us if it went out another 24 hours?  I would think so... with a 1040 HP sliding eastward into Quebec and a 1039 in ND... but the SLP on the OK/TX border at 1003mb is giving me slight pause with the h5 energy/shortwave being a bit far behind -- or is that the kicker?

Also, I'd think that huge ocean low would help with the HP getting blocked up in Quebec, yes?

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Let's see what's going on here at 98hrs

gfs_namer_098_sim_radar_comp.gif 

This would be a great chance to trend west if not for this complete depletion of reverse-Dec -PNA. It's too strong otherside/+PNA. We miss it. NAO-PNA are running together wrt every storm. ^1040mb High pressure, we aren't even that cold believe it or not

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