January 5-6 Thing II: STORM MODE

[nj2va]

3 minutes ago, stormtracker said:

WB has it as sleet or something according to Will's map.  You have the sounding?  Sometimes WB paints sleet in snow/close snow situations 

ETA: Nevermind.  Saw you edited and said you checked the sounding

This is the 15z sounding, probably some sleet mixing in but column cools by 18z.

[yoda]

1 minute ago, WxUSAF said:

That’s sleet 

800mb is barely over the line FWIW, everything else is 0c or lower

@nj2va shows it better above

[CoastalWx]

2 minutes ago, yoda said:

I would posit that as long as the precip doesnt get too light, it should remain snow since the "nose" is only a few tenths above 0c

 My experience is that these elevated warm tongues even near 0C end up as some sleet especially when you dry out the DGZ. So perhaps for DC….when the DGZ dries out, you could get some sleet or rimed flakes until the mid level lows approach and it cools. 

[stormtracker]

1 minute ago, WxUSAF said:

That’s sleet 

I agree, close but pingy for that period.  Still think northern areas get the jack...less qpf, but no changeover issues

[CoastalWx]

Could be a nice finale for DC when the mid level lows approach. 

[WxUSAF]

Just now, CoastalWx said:

Could be a nice finale for DC when the mid level lows approach. 

This is the part I want to max out. Major fluff potential.

[wxdude64]

6 minutes ago, yoda said:

That IS close

[DDweatherman]

2 minutes ago, CoastalWx said:

Could be a nice finally for DC when the mid level lows approach. 

Definitely agree. 
 

something of note for areas near mby and the northern crew along the M/D. The precip max areas have held or even moved slightly north (6z euro/eps a bit north, 12z gfs about the same as 6z). The gradient may start to appear tighter as we get closer in, and look to the higher res models to help define that cutoff. In truth, a sharper cutoff is likely more indicative of where a deathband could set up overlapping the fronto&divergence. We’ve seen this movie several times. Those yellows on radar will also probably be putting out 15:1+ ratio growth and no mixing risk up this way. 

[stormtracker]

Quiet in here, lol.   Hope I didn't scare people too much.  Yall can't talk about your area and ask for soundings etc.  Let's just keep it wx related and not bantery 

[dallen7908]

College Park area also flirting ... 

[nj2va]

3 minutes ago, WxUSAF said:

This is the part I want to max out. Major fluff potential.

Get this more expansive and it’d be a fun finale.

[yoda]

12z CMC is a big hit -- all snow DC metro... prob EZF as well

[H2O]

Just now, nj2va said:

Get this more expansive and it’d be a fun finale.

That there can help the areas south of DC that might see some mixing.  But expand more and everyone can add onto the WAA thump

[Kevin Reilly]

2 minutes ago, DDweatherman said:

Definitely agree. 
 

something of note for areas near mby and the northern crew along the M/D. The precip max areas have held or even moved slightly north (6z euro/eps a bit north, 12z gfs about the same as 6z). The gradient may start to appear tighter as we get closer in, and look to the higher res models to help define that cutoff. In truth, a sharper cutoff is likely more indicative of where a deathband could set up overlapping the fronto&divergence. We’ve seen this movie several times. Those yellows on radar will also probably be putting out 15:1+ ratio growth and no mixing risk up this way. 

Hmmm how about those higher ratios in southern PA over to southeast PA with .30" liquid I would think 4-6" of snow. 

[Buddy1987]

2 minutes ago, yoda said:

12z CMC is a big hit

I-66 just absolutely raked at 48!

[clskinsfan]

CMC is 22 degrees in DC at onset. 

[nw baltimore wx]

Moving this over here from banter, but I think even up here I could go to sleet for a time. No mechanism up north to keep a warm layer from coming up the bay, and I’m east enough that it happens here in big storms.

[DDweatherman]

Just now, Kevin Reilly said:

Hmmm how about those higher ratios in southern PA over to southeast PA with .30" liquid I would think 4-6" of snow. 

Absolutely. It’s like @psuhoffman said, just stay at the .3” or above qpf line and roll the dice. It’s rare we are snowing in the low 20’s with a strong system driving in from the W/SW optimizing flow with good fronto nearby. 

[Interstate]

The system has just become overall drier on the 12z runs according to the snowfall maps.

[IronTy]

Can't find anything to complain about on the 12Z GFS verbatim.  Euro up next, time to bring her home.  

[DDweatherman]

Just now, Interstate said:

The system has just become overall drier on the 12z runs according to the snowfall maps.

It’s a little faster, and maybe the slightest bit of de-amping of the vort again that we saw the other day as it gets east. Euro was actually wetter at 6z but GFS is a bit drier. 

[Kevin Reilly]

1 minute ago, Interstate said:

The system has just become overall drier on the 12z runs according to the snowfall maps.

Could it be because the air is drier and colder that the storm is running into?

[clskinsfan]

It seems to me to be a 4-8 type storm if we are being realistic. Maybe some double digit spots. But this isnt a super juiced up bomb. 

[stormtracker]

Just now, IronTy said:

Can't find anything to complain about on the 12Z GFS verbatim.  Euro up next, time to bring her home.  

I'm not going to lie, the model differences at this point just have me....confused.   Relative to our area, they are just all over the place.  

[DDweatherman]

Just now, Kevin Reilly said:

Could it be because the air is drier and colder that the storm is running into?

It’s 25/11 in my neck of the woods here at peak heating for January, pretty chilly. However, not crazy dry. 

[SomeguyfromTakomaPark]

Just now, clskinsfan said:

It seems to me to be a 4-8 type storm if we are being realistic. Maybe some double digit spots. But this isnt a super juiced up bomb. 

With an 8-12+ zone in that sweet spot where the banding makes it without temp issues. 

[bncho]

Just now, stormtracker said:

I'm not going to lie, the model differences at this point just have me....confused.   Relative to our area, they are just all over the place.  

We're only 36 hours from the onset of the storm and the models still don't know whether DC will be on the northern fringe, on the bullseye, or on the southern fringe. We need a good Euro run.

[DDweatherman]

1 minute ago, clskinsfan said:

It seems to me to be a 4-8 type storm if we are being realistic. Maybe some double digit spots. But this isnt a super juiced up bomb. 

For the most part, I’d agree. However, 1” QPF or more in areas in our lowest PWAT month is anomalously juiced. Not to mention, we really should maximize snow growth here, which is more the reason this could overperform totals wise. We’ve heard it from several of our met colleagues certain spots will be 10-12”+ if they are under bands for several hours. 

[WesternFringe]

7 minutes ago, stormtracker said:

I'm not going to lie, the model differences at this point just have me....confused.   Relative to our area, they are just all over the place.  

Same.  So far, the north/warmer camp won’t cave to the south/colder camp and vice versa.

Initially, I thought the model wars were intriguing and fun to watch unfold, but now being so close to the onset of the storm it is just plain annoying. 
 

On the bright side, at least we are all tracking and wintry precip is inbound! 

[high risk]

27 minutes ago, Weather Will said:

 

          I'm trying to make sense of these WB maps.     It appears that they are NOT forecasts of precip type right at the particular time.    The label says "6 hr QPF by type (in.)", and legend below notes that it's liquid equivalent.   But since there is no way to plot amounts of each type on a single map when precip types varies during a 6h period, we have to figure out what they're doing.    The GFS does not parse amounts by type, so my guess is that WB does some sort of internal tallying by using hourly precip type data and hourly QPF, and they plot whichever type is the highest over the previous 6h, but that's admittedly an assumption.   Regardless, no one should interpret this map as "it's sleeting or freezing rain at 18Z over most of the area."