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April 7-8 snow event

PrinceFrederickWx

By PrinceFrederickWx,
in Mid Atlantic

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Bob Chill

Bob Chill

Posted
Posted
53 minutes ago, psuhoffman said:

Excellent post. Many of our past snow events didn't even begin to present as a threat until day 3-4 and were still evolving until inside 48 hours. I could lost off dozens of our warning events years past that that weren't even a thought at 5 days out. 

I think the success at crazy long leads of the 2010 and 2016 storms created an unrealistic expectation. And now some were taking guidance at day 4+ way more seriously then we should. Some recently have been referred to 72-100 hour timeframe model output as "short range" that's barely medium range really.  I think part of the problem is perception and we are stretching out expectations faster then the guidance warrants. 

The guidance has had a bad year. But some are expecting too much at long leads also. 

You and I have remarkably similar takes on NWP. I've said this before but I'll reiterate because I often use the short/med/lr terms but it is subjective

Short range = 72 hours and in but 72 is the outer limit of short range

Med range = 72-144 hours but 120-144 is the outer limit. 

Long range = day 6+

This year has had a remarkable number of "events" break the wrong way at all ranges. Especially med range but I don't ever get invested beyond 5-6 days at the longest. Interested in long range? Hell yeah. Bummed or mad at NWP when something vaporizes beyond 5 days? Rarely if ever....

We've had years where things break right more often than not and they become a benchmark for future expectations. But our grading is flawed by emotions. I'm as guilty as the next guy at times. 

The 13-15 stretch had many med range threats morph into different events but considered them a "win" with guidance. In reality, the med range busted horribly but since it snowed anyway it was a "win" so NWP performance got higher grades than they should have. This year NWP is getting bashed in the med range because we barely caught any breaks this year. Lol. Verification scores in general are always improving even if very gradual but our grading scale goes up and down based on ground truth in tiny little Itty bitty postage stamps on the planet called our yards. 

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psuhoffman

psuhoffman

Posted
Posted

When I was in the meteorology program at PSU I know the nws considered short range 0-48 hours. Medium 3-5 days and long range anything past 5. I've been out of the loop for a while though so not sure if those still hold. I guess I've always had that stuck in my head  

Either way we are on the same general page. I lol at the NWP critics that blast it when models shift a threat at day 7. I think " so your going to do a better job by extrapolating current conditions?"  I'm not knocking good sound meteorological rules and climo knowledge. I use those too. Have to adjust for climo all the time to correct guidance. But to rely on that exclusively is nuts. We used to have to do that and forecasts past 24 hours were a crap shoot. Even the best can't outperform the NWP past a day or two. 

I do wonder if the bias corrections gave hurt. I feel like it used to be easier to correct for them as each model seemed to have more consistent errors. Now they are better but when they are wrong it's in less predictable ways. Makes it more difficult to correct and anticipate the errors. That's frustrating. 

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BristowWx

BristowWx

Posted
Posted
2 minutes ago, SnowGolfBro said:

It’s probably over. But i have this strange feeling that we are going to get shellacked on Saturday. I may just be channeling my inner Jebman

Maybe.  Can’t trust the SREFs. Globals stink right now.  Who knows

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Fozz

Fozz

Posted
Posted
2 hours ago, Maestrobjwa said:

If we're gonna fail, I'd much rather it be like last year...Missed chances and near-misses feel far worse than a total shutout pattern like 2017. This winter mentally took it's toll, lol (whereas last winter there wasn't much expectation or buildup because we were never in the game in the first place!) Snow everywhere around hurts worse...mercy

I recall last year being just like this one with tons of screwjobs, and being in a snow hole while areas all around us did better. One difference though was that it was much warmer than this year, so maybe that made it less painful for some.

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psuhoffman

psuhoffman

Posted
Posted
2 minutes ago, NorthArlington101 said:

NAM actually moves a handful of precip up north, not sure it’s gonna matter but it’s interesting. Maybe because of the SLP it pops in GA?

It's trending weaker with what was out Saturday wave. It's almost non existent now. But it's leaving more and more behind and now that trailing wave is actually our best bet. Not a good bet but it's all we got. 

Im not sure if it's actually another wave or if everything is just slowing down and that's the wave that was our threat and it's just ejecting a small bit of energy along the front now and leaving most behind. Either way you get the idea. 

Problem is by slowing down the front presses well south so by Saturday evening for that wave to work it has to be way more amplified in order to get ridging in front and push the boundary back north. So the timing is now off. The wave is coming at us once the boundary has passed to our south and as of now it's not strong enough to lift it back. 

I'm tired. Long day. Hope that made sense. 

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Cobalt

Cobalt

Posted
Posted
1 minute ago, psuhoffman said:

It's trending weaker with what was out Saturday wave. It's almost non existent now. But it's leaving more and more behind and now that trailing wave is actually our best bet. Not a good bet but it's all we got. 

Im not sure if it's actually another wave or if everything is just slowing down and that's the wave that was our threat and it's just ejecting a small bit of energy along the front now and leaving most behind. Either way you get the idea. 

Problem is by slowing down the front presses well south so by Saturday evening for that wave to work it has to be way more amplified in order to get ridging in front and push the boundary back north. So the timing is now off. The wave is coming at us once the boundary has passed to our south and as of now it's not strong enough to lift it back. 

I'm tired. Long day. Hope that made sense. 

So basically, this storm sums up our entire winter so far

Promising medium/long range looks

A medium-short range shakeup

A storm we didn't even sign up for (the 2nd wave) 

And hope for a NW trend (with the NW trend probably only helping Richmond)

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Jebman

Jebman

Posted
Posted

There's a reason snows in April are rare around here lol.

With that said, I really wish this could have worked out, at least for the mountains and the favored places in MD. It would have done me a great deal of good to see Mappy, PSU and Chill buried in 16 inches of wet spring snow.

 I would have happily taken 7 inches of 33 degree torrential rain so that the above locations could get severely shellacked with snow.

That, would have made my entire year!

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high risk

high risk

Posted
Posted
5 minutes ago, Amped said:

Why the heck is the NAM showing snow accumulation in NC if it never gets the R/S line that far south?   That has to be an error.

     because the snow accumulation (which includes sleet) is from the model microphysics, while the precip type is from the wet bulb temperature profile

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Jebman

Jebman

Posted
Posted
44 minutes ago, SnowGolfBro said:

It’s probably over. But i have this strange feeling that we are going to get shellacked on Saturday. I may just be channeling my inner Jebman

LOL, but models may be still be working this out. Things will look better 24 hours from now. NEVER EVER give up!

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WeatherShak

WeatherShak

Posted
Posted
1 hour ago, psuhoffman said:

When I was in the meteorology program at PSU I know the nws considered short range 0-48 hours. Medium 3-5 days and long range anything past 5. I've been out of the loop for a while though so not sure if those still hold. I guess I've always had that stuck in my head  

Either way we are on the same general page. I lol at the NWP critics that blast it when models shift a threat at day 7. I think " so your going to do a better job by extrapolating current conditions?"  I'm not knocking good sound meteorological rules and climo knowledge. I use those too. Have to adjust for climo all the time to correct guidance. But to rely on that exclusively is nuts. We used to have to do that and forecasts past 24 hours were a crap shoot. Even the best can't outperform the NWP past a day or two. 

I do wonder if the bias corrections gave hurt. I feel like it used to be easier to correct for them as each model seemed to have more consistent errors. Now they are better but when they are wrong it's in less predictable ways. Makes it more difficult to correct and anticipate the errors. That's frustrating. 

Did you study under Titley?

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