January 24-26: Miracle or Mirage Thread 2

[SomeguyfromTakomaPark]

1 minute ago, umdterps29 said:

Right at the end of the storm? Doesn't that radar indicate there would still be many hours of precip left to go?

I think in this setup it's gonna come in hot and heavy and the vast majority of our QPF will be before 18z on Sunday and maybe even before 15z.  Without a 2 part coastal thing thats usually how it goes.  Just some light stuff from these panels on.

[mitchnick]

Just now, soadforecasterx said:

So why does this map show something different? 

Virga vs fallen

[yoda]

Just now, soadforecasterx said:

So why does this map show something different? 

Composite vs 1km Above Ground Level radars

[psuhoffman]

The 18z NAM is better than the 12z and was about to obliterate us...and that is the end of my analysis of the NAM at 84 hours.  

[Maestrobjwa]

4 minutes ago, WxUSAF said:

Look at where that big northern shortwave enters the country around 78hrs. Much farther east than 12z. Continuing to 84hrs, part of the difference is speed, but it’s still east. I like that. Would like to see that same thing on the varsity models.

So what is the importance of it being more east again?

[GreyHat]

5 minutes ago, yoda said:

hr 84

 

I like how this .ap looks with that 1043 HP positioned. That would keep any ice from come up to DC, Baltimore and Delaware.  I would think. Maybe after some good sampling things will look more in line with this setup.

We have seen a lot of possibilities this morning and now the 18z's.

[LeesburgWx]

NAM was primed man. Like primed. and a 1043 H just north of us. 

[LP08]

6 minutes ago, psuhoffman said:

Once it's in range...I would trust the NAM over other guidance with the thermals and precip type zones associated with that.  Not at 84 hours...but once were close.  Especially the 3k.  It's the only thing I do trust the NAM with over other guidance.  

Always.  3k is great for that.  Find the mix line and add 10-20 miles north and it’s pretty dang good

[TSSN+]

Just now, Maestrobjwa said:

So what is the importance of it being more east again?

Better to keep the high in place and not phase as much if the energy is more separated.

[IUsedToHateCold]

1 minute ago, Maestrobjwa said:

So what is the importance of it being more east again?

My layman's understanding is that we don't want the low to phase too early or too strongly or else it will punch through the high and cut. If it holds back to the west that is more likely to happen. 

[baltosquid]

Too early to diagnose much but the ICON at 30 is isolating the Baja low a bit more than 12z and MIGHT be tightening up that NS energy that had been jutting west; next few frames should tell.

[weathercoins]

11 minutes ago, yoda said:

hr 84

 

These panels showing the onset of the snow just hitting us - with precip still in Texas and west, and no mixing until you pass Virginia - are just beautiful  

[WxUSAF]

5 minutes ago, Maestrobjwa said:

So what is the importance of it being more east again?

 

3 minutes ago, IUsedToHateCold said:

My layman's understanding is that we don't want the low to phase too early or too strongly or else it will punch through the high and cut. If it holds back to the west that is more likely to happen. 

Yeah, any weaker/more easterly northern wave helps reduce chances of a GGEM scenario. 

[Terpeast]

Dangerous to buy into the NAM trend, but it was within its range (60hr) when it spaced the NS and SS waves apart and strengthened confluence. We'll see if other models do the same and backtrack its NW trend.

[umdterps29]

Is this the type of storm where we will lose some precip to virga at the start, or are we expecting it to come in juicy?

[Eskimo Joe]

RE: watches. @stormtracker was right to call me out on my hours being off. My brain had a major hiccup. Might see watches late tonight or tomorrow. Would wonder if LWX/CTP wait to see the 00z suite before pulling the trigger.

[baltosquid]

Yeah, at 42 the ICON definitely has tightened up the NS kink and kept it further east. It also has more confluence over the central CONUS. Can’t feel too good though until we see it de-amp verbatim though, not sure how the interaction will go even with some separation

[psuhoffman]

13 minutes ago, soadforecasterx said:

So why does this map show something different? 

one is simulated radar and the other is the previous time period precip, different things tend to show...different things 

[WxUSAF]

Just now, umdterps29 said:

Is this the type of storm where we will lose some precip to virga at the start, or are we expecting it to come in juicy?

It will virga for awhile, lower atmosphere will be super dry. So expect the “donut hole” look on radar. But we won’t “miss” any precipitation because of that. Models account for that. Once the column saturates, it will probably go from light flurries to steady snow quickly. 

[Stormchaserchuck1]

Just now, umdterps29 said:

Is this the type of storm where we will lose some precip to virga at the start, or are we expecting it to come in juicy?

The maps we are posting is accumulated precip. There may be some virga Sat night but that's not counted. 

[TSSN+]

2 minutes ago, umdterps29 said:

Is this the type of storm where we will lose some precip to virga at the start, or are we expecting it to come in juicy?

This will come in like a brick wall. Won’t take long for it to start snowing 

[umdterps29]

1 minute ago, WxUSAF said:

It will virga for awhile, lower atmosphere will be super dry. So expect the “donut hole” look on radar. But we won’t “miss” any precipitation because of that. Models account for that. Once the column saturates, it will probably go from light flurries to steady snow quickly. 

Didn't realize the models were able to account for that. Thanks!

[DDweatherman]

Just now, TSSN+ said:

This will come in like a brick wall. Won’t take long for it to start snowing 

Especially advection precip, not usually an issue. 

[MN Transplant]

One thing that I'm noticing is that the models with a stronger 850 low in the central US are the ones that are able to drive it up to Cleveland and eventually draw up the warm sector for us at the end of the storm.  The GFS does not do that, with a weak 850 low that is eventually replaced by a new low that forms off of Cape May, NJ.

[soadforecasterx]

18z icon seems to follow the nam trend of going back to the overrunning type system vs the amp'd solution 

[stormtracker]

ICON is also a touch flatter out front

[Paleocene]

I'll let someone more qualified than me comment on meaning, but here's ICON 18z (top) versus 12z (bottom).  Valid Saturday 12z. Baja wave looks more organized and more positively tilted. Northern stream energy has a different position too

[Solution Man]

2 minutes ago, soadforecasterx said:

18z icon seems to follow the nam trend of going back to the overrunning type system vs the amp'd solution 

That’s what we want

[Eskimo Joe]

3 minutes ago, soadforecasterx said:

18z icon seems to follow the nam trend of going back to the overrunning type system vs the amp'd solution 

A nice, easy warm advection snow event would be the best. No mixing, just cold powder.

[psuhoffman]

1 minute ago, stormtracker said:

ICON is also a touch flatter out front

so far 18z (NAM/ICON) coming in with slightly better confluence in front of the system and a flatter flow over the top.  Not major changes but we don't need major changes.  These changes are showing up at 48 hours which is a pretty believable range...if we see this continue across 18z guidance it would be a significant step in the right direction of avoiding the over amplified solutions.