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Outta gas and Outta Time: Early March Winter Storm finale

Ji

By Ji,
in Mid Atlantic

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Bob Chill

Bob Chill

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Upper levels have looked pretty blah on this one since the beginning. I agree with Wes about the overcooked potential and that's why I've been quiet. It's just not adding up for a 6" snowfall anywhere. Weak sauce won't do it with surface temps so I've been leaning towards SnowTV at best and I also don't think it ends up hitting my yard. Central VA thru the DMV is the most likely area to see any snow falling. 

If I only saw this panel on the GFS I would never think a 6" snowfall would be the outcome. I would think a swath of scattered light precip and not a shield that drops .5+qpf.

image.thumb.png.b8594b83f9d827b3f9e559212693a057.png

 

All that said, models haven't locked into the strength of the shortwave and it definitely bears watching for accum snow for someone. The setup with the HP pressing into the precip is much better than HP running away. With enough lift pushing against a modest shortwave it can maximize potential in narrow stripe. 

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You're not a real one unless you are following a potential Warning criteria event that will likely turn into a slushy inch with temps of 33 degrees.  But by the time you realize that, you will be way

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87storms

87storms

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8 minutes ago, Bob Chill said:

Upper levels have looked pretty blah on this one since the beginning. I agree with Wes about the overcooked potential and that's why I've been quiet. It's just not adding up for a 6" snowfall anywhere. Weak sauce won't do it with surface temps so I've been leaning towards SnowTV at best and I also don't think it ends up hitting my yard. Central VA thru the DMV is the most likely area to see any snow falling. 

If I only saw this panel on the GFS I would never think a 6" snowfall would be the outcome. I would think a swath of scattered light precip and not a shield that drops .5+qpf.

image.thumb.png.b8594b83f9d827b3f9e559212693a057.png

 

All that said, models haven't locked into the strength of the shortwave and it definitely bears watching for accum snow for someone. The setup with the HP pressing into the precip is much better than HP running away. With enough lift pushing against a modest shortwave it can maximize potential in narrow stripe. 

I’m looking forward to a pattern that actually favors a consistent return of gom moisture. With the nor’easter, the Atlantic finally said, “I’ll do the job”, though that’s not our best path to victory here. The lack of a stj and gulf influence is by far the number 1 reason for the northern md snow drought. I expect that once El Niño settles we won’t have so much of this nickel and dime, hit or miss stuff.

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hosj III

hosj III

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1 hour ago, psuhoffman said:

Maybe this is perception bias, but when it came to my ability to predict what a significant storm would end up doing from the guidance, it was easier for me in the late 90s and early 2000s with the old school MRF/AVN/GGEM/ECMWF and short range ETA/NGM.  Those models were way way way less accurate, but they tended to be less accurate in a more consistent way.  They each had very very very universally consistent bias errors and if you knew how to correct for them they were useful.  Now...they are all more accurate in that they are more likely to be closer to the actual truth.  But they are much higher resolution and their errors tend to be less consistently in the same direction.  This makes it much harder to correct for them and determine what their errors are.  Not trying to be controversial here, and I could be wrong...but at times I felt it was easier to forecast using the models 20 years ago in the medium range than now.  

I think its some combination of rosy retrospection and improvements in model accuracy being met with immediate attempts to extend forecasts further. 

I haven't been watching them nearly as long or nearly as well as you have, but in my view the improvements since 2010 are obvious and enormous. 

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SnowenOutThere

SnowenOutThere

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1 hour ago, psuhoffman said:

It really dampens the wave around 90-96 hours.  It doesn't eject enough energy, most of it hangs back, the wave dies with no mid and upper level support at all as it slides east.  

Yeah. Some solutions a couple days ago pushed more energy eastward with this wave so it had more support but now it seems like a lot just barely eject anything. Oh well. 

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psuhoffman

psuhoffman

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29 minutes ago, hosj III said:

I think its some combination of rosy retrospection and improvements in model accuracy being met with immediate attempts to extend forecasts further. 

I haven't been watching them nearly as long or nearly as well as you have, but in my view the improvements since 2010 are obvious and enormous. 

This definitely has merit, thinking back in the late 90's and early 2000's stuff at day 3-5 was treated like we look at stuff day 7-10 now.  We didn't even try to look at a specific storm threat past day 5, most of the models didn't even run past 144 hours and it was a complete waste of time.  

Usually by 72 hours we have  pretty good idea what the major features will be, but now we also expect meso scale things to be right and that was never a thing in the past.  And in marginal setups where a 1-2 degree difference is huge, expecting models to nail that is crazy.  But some people do now.  

So maybe it's also a case of expectations increasing faster than the actual improvements which gives the perception things are worse.  I do think there is some truth the the decreased consistency of bias errors but it's likely not as bad as I am perceiving it.  

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TSSN+

TSSN+

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1 minute ago, stormtracker said:

I'd be excited if it wasn't just AI.  I mean, have they really been as good as advertised? 

Meh I mean it showed us getting 20”+ for this past weekend for multiple runs at this range so

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mitchnick

mitchnick

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1 minute ago, stormtracker said:

I'd be excited if it wasn't just AI.  I mean, have they really been as good as advertised? 

Off and on, though better "at times" imho. But you never know if this is one of those times. Would prefer the AI and operational to agree.

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psuhoffman

psuhoffman

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4 minutes ago, stormtracker said:

I'd be excited if it wasn't just AI.  I mean, have they really been as good as advertised? 

Verification scores don't lie.  However, when all we care about is how much snow ends up on our lawn, that doesn't always necessarily correlate to some hemispheric h5 or MSLP verification score!  Also, sometimes we see a model leading the scores chart and think "that means it's right" when it really means it's slightly less wrong than the others.  

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psuhoffman

psuhoffman

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3 minutes ago, TSSN+ said:

Meh I mean it showed us getting 20”+ for this past weekend for multiple runs at this range so

But this point is actually a great example of what I meant by "when all we care about is how much snow falls in our yard it might not align with verification scores".  Yes the AIFS had multiple runs in the day 5-8 range with HECS snowfall results for our area.  But, those results were real, just displaced about 150 miles to the northeast.  And no other model, at those ranges, were even close...the GFS didn't start showing those crazy snow totals until like day 4 out.  So when compared to all the other models, which didn't have an HECS anywhere at all...the AIFS which had it but displaced a small amount too far southwest, the AIFS was by far the closest to the truth (the less wrong) model in the day 5-8 period.  

We look at them all wrong, in that we expect them to be exactly right at a range that there is almost no chance they will be.  The AIFS showing a HECS somewhere in the northeast at all day 5-8 was a win for it...but we think it was wrong because the big snow ended up not over us.  

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TSSN+

TSSN+

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3 minutes ago, psuhoffman said:

But this point is actually a great example of what I meant by "when all we care about is how much snow falls in our yard it might not align with verification scores".  Yes the AIFS had multiple runs in the day 5-8 range with HECS snowfall results for our area.  But, those results were real, just displaced about 150 miles to the northeast.  And no other model, at those ranges, were even close...the GFS didn't start showing those crazy snow totals until like day 4 out.  So when compared to all the other models, which didn't have an HECS anywhere at all...the AIFS which had it but displaced a small amount too far southwest, the AIFS was by far the closest to the truth (the less wrong) model in the day 5-8 period.  

We look at them all wrong, in that we expect them to be exactly right at a range that there is almost no chance they will be.  The AIFS showing a HECS somewhere in the northeast at all day 5-8 was a win for it...but we think it was wrong because the big snow ended up not over us.  

I mean it was wrong lol. Just cause a model shows a low over the Midwest an it ends up in the Ohio valley doesn’t mean it was right. Ya all the models show outputs that maybe somewhat close but when we are looking at our area what happens matters. 

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NorthArlington101

NorthArlington101

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I mean it was wrong lol. Just cause a model shows a low over the Midwest an it ends up in the Ohio valley doesn’t mean it was right. Ya all the models show outputs that maybe somewhat close but when we are looking at our area what happens matters. 

I think the broader point is that verification scores aren’t gonna translate to specific areas for specific events… just not how it works. You can take or leave them as how a model performs if you want to but it’s kinda the only objective measure

And it’s correct to say the AIFS was first to ID a big east coast storm. It was just wrong for us. But thr GFS was even more wrong!
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