March 11-12 Storm - Model Discussion STORM MODE

[WxMan1]

1 minute ago, Cobalt said:

Very much so, but thanks a ton for clearing this up 

No prob!

[Cobalt]

Very true

 

[87storms]

7 minutes ago, Bob Chill said:

Once the storm in getting organized and models are initialized with real time info then models should probably do fairly well with track and intensity at our latitude. North of us is still subject to cascading math errors but once things are rolling in the SE, our fate will be largely determined. I strongly believe that a Jan 2000 type of bust is very unlikely to occur ever again. Going from nothing at all to all in in under 24 hours is probably a thing of the past. Jan 2000 was literally a complete whiff for the entire State within 24 hours IIRC. 

yea, i just think we could see something similar, but it would take a more complicated setup than that one.  pound for pound, i think the models now would handle that particular setup better, but add 1 or 2 more rare pieces and maybe that's where current technology is susceptible to something similar.  i'm completely theorizing.

[WeathermanB]

Trof is a little farther south than yesterday's 12z run at same time.

12z Sat vs

12z Fri run

[ErinInTheSky]

Euro gives us snow for the first time in what, 10 runs?

[WeatherShak]

A lot of people have been asking if the models have ever flip flopped this much before and how crazy it is... I have one word for them - Joaquin.

If I remember correctly everyone caved to the Euro on that one which was rocksteady OTS the whole time.


.

[Cobalt]

Doesn't look as juiced up as the GFS. At 18z Monday the Euro has light snow falling & has temps at 38-39 degrees for DC. During the same time the GFS has moderate-heavy snow falling with temps at 34/33 degrees. Honestly, I don't care at this point. The Euro moved NW, and that's all that matters

[WeathermanB]

Shifts closer to SNE

[Roger Smith]

Run a satellite animation for past 12-18 hours and you'll see there's a large amount of energy sitting over the east-central Gulf of Mexico waiting to phase into this system. The mild air is sitting in place as far north as w KY so there's quite a broad area for cyclogenesis. The key to getting this system to max out will be if the land-based surface low can pull in that Gulf energy when it crosses FL on Sunday. Then it can tuck and throw back moisture all day Monday, with the usual northward trend of real snow vs model snow you appear to be in the sweet spot.

First call 5 to 8" 

[eurojosh]

This storm should be called the Felix storm because it has more lives than a cat.

Anyway, looking at the GFS, what strikes me is the odd leap back towards the coast the LP takes between 54-60.  At the upper levels there seem to be two things driving that.  The first is the steering flow at 250mb.  Look at how it cuts underneath the LP, pushing it back towards the coast:

 

 

Compare that to previous runs that didn't create a coastal, like yesterday's 12z:

 

 

The steering flow is further north and runs right into the LP, pushing it offshore.

The second factor I noticed is on the other side - the north (need to post separately due to size limits)...

 

[87storms]

Just now, Cobalt said:

Doesn't look as juiced up as the GFS. At 18z Monday the Euro has light snow falling & has temps at 38-39 degrees for DC. During the same time the GFS has moderate-heavy snow falling with temps at 34/33 degrees. Honestly, I don't care at this point. The Euro moved NW, and that's all that matters

how much further west are we talking?  i don't have access to the maps, but curious how much of a shift took place since we still have probably like 24 hrs to trend better (based off of what we've seen so far lol).

[ErinInTheSky]

Just now, WeatherShak said:

If I remember correctly everyone caved to the Euro on that one which was rocksteady OTS the whole time.


.

Eventually. But we had solutions ranging from Georgia to Maine to OTS 36 hours out.

[clskinsfan]

Euro gets light snow even out to here. You have to love the trend today at 12Z

[WeathermanB]

GEPS just coming out now on tidbits the game is on..

[Cobalt]

1 minute ago, 87storms said:

how much further west are we talking?  i don't have access to the maps, but curious how much of a shift took place since we still have probably like 24 hrs to trend better (based off of what we've seen so far lol).

This

vs

I bet if it were juiced up like the GFS the DC area would've gotten at least an inch or mote on the 10:1 ratio. Baby steps, even this close in

[87storms]

Just now, Cobalt said:

This

vs

I bet if it were juiced up like the GFS the DC area would've gotten at least an inch or mote on the 10:1 ratio. Baby steps, even this close in

thanks.  that's quite a shift.

[eurojosh]

So... on the northern side.  You can see the difference in the heights at 500mb, but adding the vorticity really underlines the difference.  Here's 12z today, with the vorticity rounding the trough and 'capturing' the LP:

That's a huge difference from yesterday's much flatter run that didn't allow the northern trough to sharpen until after the southern stream had departed:

Bottom line - part of the complexity here is that a favorable track depends on both the steering winds and the 500mb pattern coming together with exactly the right timing.  I think even for another 24 hours that timing won't be clear, and there's still the chance for a complete miss or a flush hit.  It's that close!

[ErinInTheSky]

Everything is shifting in the right direction. I don’t think we will get warnings level snow but I’m willing to believe we at least get SOMETHING out of this.

[stormtracker]

Well, the trend today is real.  Let's see if we can keep it going.  Also helps to confirm this new evolution

[H2O]

Still storm mode.  Please keep posts to only discussion and on topic.  

[ErinInTheSky]

Just now, Chase said:

Well now we need rates because the 32* line is way up north. 

I saw that - euro gives some serious temp concerns for sure.

[WeathermanB]

Man this would be funny if we go from nothing to a winter storm warning right before the snow starts.. like 6 hours before it does lol

[Cobalt]

1 minute ago, supernovasky said:

I saw that - euro gives some serious temp concerns for sure.

Like I said, the GFS during the same 18z panel on Monday, the GFS shows moderate-heavy snow, and temps are sorta suitable for accumulating snow

While the Euro was something like 38-39 degrees with snowfall rates at 0.05"/hr. Can't post since I'm at my image limit, but I may post it in a bit 

[BristowWx]

1 minute ago, WeathermanB said:

Man this would be funny if we go from nothing to a winter storm warning right before the snow starts.. like 6 hours before it does lol

GFS has warning criteria snow in PWC.  So not impossible.  

[MD Snow]

14 minutes ago, supernovasky said:

I saw that - euro gives some serious temp concerns for sure.

Any snow in March will live or die with rates. You have to have rates to have accumulating snow in March. Think about Tuesday night. Temp was 38 at onset and bottomed out at 33 and I got 2.5 inches in 3 hrs. If it happens this will probably be during the day so we'll be dealing with other issues on top of temps. But rates can overcome even those daytime issues. If it's gonna work during the day we absolutely have to have moderate/heavy snow for an extended period of time to get accumulations.  

12z EURO is our fail solution. Skips right over us and rocks NYC north. 

[psuhoffman]

31 minutes ago, Bob Chill said:

I don't disagree with the premise but those amped/north solutions are probably more of a byproduct of an amped/north op and/or control run than an expression of increased probability. If 18z comes in flat and disjointed then it's going to be a wholesale shift with the ensembles. I know you know this and I think we're on the same page but the short story is we both could have predicted that the GEFS is going to look really sweet based on the op run before the panels came out. 

What will you think if the euro makes no appreciable change from the 0z solution? We both know the EPS will also show low probability of a good hit too...then what? I would just blend the 2 ops and say the most likely outcome is somewhere in between. Now if the euro op makes a sig shift towards a gfs solution then it's probably game on for at least a portion of the sub... Tricky storm. 

Yea and I agree the ensemble usefulness is greatly reduced inside 72 hours. One thing I do think they can help with still is if the op simply has a bogus run. Rare at short leads but sometimes. And I do think there is still an envelope of error with the op. It's less but still there. And the ensemble can hint if the op was on one side of that envelope. In this case the ensemble hints the op might have been on the more suppressed side. The wider then normal variance also hints this is not as resolved as usual at this range. If they all looked the same then we know the op has high confidence in that outcome. Doesn't mean it's right. But higher probability. So I still get some hints and clues from the ensembles here but i think I'm looking close and from a general 1000 feet pov they aren't useful to make a forecast based on them anymore.  That's just my 2 cents. 

[Buddy1987]

May I ask if anyone has qpf or snow totals for southern and central VA? I’m out right now and don’t have access.

[WeathermanB]

 

A lot less spread than the 00z run this morning. GEPS ensembles.

[psuhoffman]

38 minutes ago, Bob Chill said:

Once the storm in getting organized and models are initialized with real time info then models should probably do fairly well with track and intensity at our latitude. North of us is still subject to cascading math errors but once things are rolling in the SE, our fate will be largely determined. I strongly believe that a Jan 2000 type of bust is very unlikely to occur ever again. Going from nothing at all to all in in under 24 hours is probably a thing of the past. Jan 2000 was literally a complete whiff for the entire State within 24 hours IIRC. 

I would to run today's models with the initialization from 48 hours before that storm and see what happens. I doubt it ever happens again but I could see a big error with a delicate phase type situation. It's more likely to get busts the other way where phasing fails though. That seems the bias. 

[eurojosh]

27 minutes ago, eurojosh said:

So... on the northern side.  You can see the difference in the heights at 500mb, but adding the vorticity really underlines the difference.  Here's 12z today, with the vorticity rounding the trough and 'capturing' the LP:

 

That's a huge difference from yesterday's much flatter run that didn't allow the northern trough to sharpen until after the southern stream had departed:

Bottom line - part of the complexity here is that a favorable track depends on both the steering winds and the 500mb pattern coming together with exactly the right timing.  I think even for another 24 hours that timing won't be clear, and there's still the chance for a complete miss or a flush hit.  It's that close!

 

32 minutes ago, eurojosh said:

This storm should be called the Felix storm because it has more lives than a cat.

Anyway, looking at the GFS, what strikes me is the odd leap back towards the coast the LP takes between 54-60.  At the upper levels there seem to be two things driving that.  The first is the steering flow at 250mb.  Look at how it cuts underneath the LP, pushing it back towards the coast:

 

 

 

Compare that to previous runs that didn't create a coastal, like yesterday's 12z:

 

 

 

The steering flow is further north and runs right into the LP, pushing it offshore.

The second factor I noticed is on the other side - the north (need to post separately due to size limits)...

 

BTW - Canadian is late w/the vort and face-on with the steering flow, so fails. JMA seems to get the vort right, but misses south with the steering flow, so fails.  Going to keep my eye on those two factors for the 18z.