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With a last gasp effort, winter 20-21 refuses to give up the ghost


moneypitmike
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22 minutes ago, FXWX said:

The road temp question is always misrepresented and not assessed correctly by many... rates always win-out.  Even last night with glorified snow showers and patchy areas of  steady light snow we had to send out trucks to treat high elevation roads here in Burlington, as solid coating occurred.  The potential for big rates easily out-weighs any road temp concerns...

Yeah...it's really even arithmetically simple too -

I mean, water holds ~ 4 kilo-joules per KG degree K, and concrete and other pavement aggregates are ~ 1 ...

...thus, just on napkins water is 4 X's more so than most street materials.

At a more complex conceptual level...yeah, we can get into differential cooling rates within the strata of the subtsrate, to actual contact surface of the road..   But that also means that at a given temperature of pavement, snow falling on the pavement will melt and the cold water will absorb more heat than the road can give at that same temperature... so the road surface falls at 4 times the rate of the cold water trying to raise its temperature.  

... so if keeps snowing... the road will snow cover pretty fast -

It's always been a sort of a canard that the ground is too warm to support snow.  It doesn't make a lot of science sense when considering material physics.  That may be so at first, but it slips really fast with that the specific heat content of water being so much higher that aggregate materials of the streets.  The water wins by a factor of 4 ... such that, the temp of the concrete falls faster than the water gains heat, and that sucks the thermal momentum from the street ...etc..etc..

I've seen partly sunny 58 F early afternoons in April with snow cover on the street by 8pm that same evening -

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16 minutes ago, FXWX said:

The road temp question is always misrepresented and not assessed correctly by many... rates always win-out.  Even last night with glorified snow showers and patchy areas of  steady light snow we had to send out trucks to treat high elevation roads here in Burlington, as solid coating occurred.  The potential for big rates easily out-weighs any road temp concerns...

But Many pro METS don’t seem to get this..especially at NWS?  What gives? 

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So ...frankly I am a bit surprised the Euro came in that robust -

It is interesting that the Euro and NAM have been sort of yawing NW then back SE ..in tandem across these last last 5 model cycles.  

That seems to suggest the variance is not so much being attributable to specific model bias' ( although they got them..), but perhaps more so with initialization/data ingest as more likely the culprit.  The NAM spent some part of the overnight with nothing - let us not forget that.  And the Euro also struggled to hold onto its earlier 12z, 4-6" advisory -type result, too.

So, yeah...movement en masse suggest the cause is broadly systemic -

That said, this really occurs to me upon deeper reflection .. it just simply comes down to rate of decay of the southern stream as it arrives.

Everything I mentioned earlier in the day when I was struggling to troll and failing - I guess they're on to me ...hm - is still true.  The total system is attenuating in that regard. But, correctly timing the rate of decay - that's bigger ball of wax; it seems that could be explained by runs getting 'that much' better ( or at least different..) data initialization.   The impetus being...strong/> momentum gets the goods further N.   The suppression is coming... but that may wait that much longer while a bigger stone rolls by in the stream underneath - metaphor...

I don't believe over land is an assimilation issue ... that seems to be more a sensitivity that arises from whether small pixels of wind max are missing or sampled -

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1 minute ago, Typhoon Tip said:

So ...frankly I am a bit surprised the Euro came in that robust -

It is interesting that the Euro and NAM have been sort of yawing NW then back SE ..in tandem across these last last 5 model cycles.  

That seems to suggest the variance is not so much being attributable to specific model bias' ( although they got them..), but perhaps more so with initialization/data ingest as more likely the culprit.  The NAM spent some part of the overnight with nothing - let us not forget that.  And the Euro struggled to hold on to the 12z's 4-6" advisory -type result in its 00z run, too.

So, yeah...movement en masse suggest the cause is broadly systemic -

That said, this really occurs to me upon deeper reflection to just simply come down to rate of decay of the southern stream as it arrives.

Everything I mentioned earlier in the day when I was struggling to troll and failing - I guess they're on to me ...hm - is still true.  The total system is attenuating in that regard. But, correctly timing the rate of decay - it seems that could be explained by runs getting 'that much' better ( or at least different..) data initialization.   The impetus being...strong/> momentum gets the goods further N.   The suppression is coming... but that may wait that much longer while a bigger stone rolls by in the stream underneath - metaphor...

I don't believe over land is an assimilation issue ... that seems to be more a sensitivity that arises from whether small pixels of wind max are missing or sampled -

People are neglecting the fact that there is also northern assist reviving the southern decay late in the game.

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yeah this is another example in why suspending the model initialization arm of operations at NCEP was a brilliant move ...

heh, kind of like the dissolution of the pandemic arm of the CDC 15 months prior to needing the pandemic arm of the CDC -  ...I mean, that scale and degree of boobery is what drive frustration to the brink of conspiracy belief system - my       f'n       god

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3 minutes ago, ORH_wxman said:

Yeah I'd prob cut the Euro 10 to 1 map in half. Not sure why Kuchie went wild....but I also don't think 8" in 5-6 hours is happening. I could maybe see 4-6 though where it snows very heavily for 3 hours.

Completely agree...this is why I liked it qualitatively speaking.

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Just now, 40/70 Benchmark said:

Completely agree.

Assuming this doesn't all of the sudden get squashed SE ala 06z NAM, a good test will be to see where the snow line is around 03z tomorrow night...if it's already snowing around ORH up to your hood by 11pm, then it's prob game-on for at least solid advisory. But if we get to 1-2am and we're still screwing around with sleet/rain near the MA/NH border, then it's prob lower end.

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4 minutes ago, Damage In Tolland said:

My guess is beat axis is from about DXR on Ne thru WBY up to ORH over to Hollis by Will. SE of that will struggle with BL and nw of that will have less qpf 

That would fit the season, so it would not surprise me, but I think north of there....ORH through NE MA/SE NH.

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  • eekuasepinniW changed the title to With a last gasp effort, winter 20-21 refuses to give up the ghost
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