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Snow/ice storm disco Feb 21-22


Damage In Tolland

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As discussed yesterday ... this is an N-stream dominate era that's been going on since mid January really... And the GFS 'tends' to be a better performer than the ECM/GGEM type models wrt to specifically the timing and spatial placement of perturbations for less-than-late-middle-range time frames....  

 

The non-GFS run types have been demoing their very typical biases, ...digging/phase too much... They appear to be correcting on cue...

 

Also, I think what this is really (looking aloft upstream, verification to date, and modeling trends combined)  all points to is a mere WAA event that fails to work into the lowest levels, prior to newly establishing baroclinic axis pressing SE of the region ... heralding in yet another in an apparently endless supply of cold air masses for the OV/Upper MA/NE... At this point in time, I am having difficulty even identifying enough mid lvl mechanics to induce anything more organized than a return flow differential thermal advection (WAA) and it suggest that's all that is in play. 

 

That new boundary stalls near the Gulf Stream as the old one that's out near Bermuda finally frontalysis' and loses thermodynamic gradient/identity altogether.  The establishment of thickness packing back west nearer the EC may then set the stage for more important, and real, amplification of the flow later next week.  The CDC/CPC has a subtle, perhaps last hurrah spike in the PNA ... a spike which may in fact be an echo of the flow amplification over the N/A aspect of the total PNA domain.  I don't think there is anything particular about the Pac circulation make-up prior, that instructs the insertion of that amplitude next week; it appears all guidance' key in on another of these trans-polar vortex nodes that careens SSE over the Canadian Prairies like we have seen several times over recent weeks.  The question is ... will the mid levels take on enough meridional flow to buckle/inflect that baroclinic zone that gets established just off the EC?  

 

The GFS is less enthused ... however, even with it's better handling of the N-stream, I don't think that necessarily is true for any model beyond D5 (duh); so there is room to adjust there.  And of course, not surprising, the ECM/GGEM/NAVGEM/UKMET ...to varying degrees, are more amplified then the GFS ... enough to consider important coastal/west Atlantic cyclogenesis.  

 

Given to the way this winter has gone over the last month, it may be tough to buck the persistence to verify toward amplitude/outcome.  Despite that ... such persistence unfortunately does not lend much to any specific model type's layout for that time frame.  The GGEM was a 2.5 day ... impossible to conceive historic snow event that would probably all but shut the region down until some kind of unilateral outside response saved lives... Ranging to the NAVGEM, which by default is much lighter....   

 

Probably something in between as the old cliche goes, but in this case, persistence combined with as yet to change pattern (though the bigger changes is still in question for beyond next week) really does provide a path of least regret ... namely, to provide band-width in folk's awareness' for something of a winter storm mid to late next week. 

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People are excited because models had taint in VT/NH/ME 24 hours ago. Now that line is barely north of RI/SE MA, and continues to trend south and east. I think we get mix in the coastal plain regardless - it's no longer trying to drive 40-45 degree temperatures where common sense said they wouldn't be in the first place.

Verbatim still taint well into New Hampshire and Maine most of mass and all of CT and RI after a few inches of snow.

If you look close warmest layer is not 850 that's why some people think it's a good run .. It's below 850 that torches we will see if this continues to cool though ..

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As discussed yesterday ... this is an N-stream dominate era that's been going on since mid January really... And the GFS 'tends' to be a better performer than the ECM/GGEM type models wrt to specifically the timing and spatial placement of perturbations for less-than-late-middle-range time frames....  

 

The non-GFS run types have been demoing their very typical biases, ...digging/phase too much... They appear to be correcting on cue...

 

Also, I think what this is really (looking aloft upstream, verification to date, and modeling trends combined)  all points to is a mere WAA event that fails to work into the lowest levels, prior to newly establishing baroclinic axis pressing SE of the region ... heralding in yet another in an apparently endless supply of cold air masses for the OV/Upper MA/NE... At this point in time, I am having difficulty even identifying enough mid lvl mechanics to induce anything more organized than a return flow differential thermal advection (WAA) and it suggest that's all that is in play. 

 

That new boundary stalls near the Gulf Stream as the old one that's out near Bermuda finally frontalysis' and loses thermodynamic gradient/identity altogether.  The establishment of thickness packing back west nearer the EC may then set the stage for more important, and real, amplification of the flow later next week.  The CDC/CPC has a subtle, perhaps last hurrah spike in the PNA ... a spike which may in fact be an echo of the flow amplification over the N/A aspect of the total PNA domain.  I don't think there is anything particular about the Pac circulation make-up prior, that instructs the insertion of that amplitude next week; it appears all guidance' key in on another of these trans-polar vortex nodes that careens SSE over the Canadian Prairies like we have seen several times over recent weeks.  The question is ... will the mid levels take on enough meridional flow to buckle/inflect that baroclinic zone that gets established just off the EC?  

 

The GFS is less enthused ... however, even with it's better handling of the N-stream, I don't think that necessarily is true for any model beyond D5 (duh); so there is room to adjust there.  And of course, not surprising, the ECM/GGEM/NAVGEM/UKMET ...to varying degrees, are more amplified then the GFS ... enough to consider important coastal/west Atlantic cyclogenesis.  

 

Given to the way this winter has gone over the last month, it may be tough to buck the persistence to verify toward amplitude/outcome.  Despite that ... such persistence unfortunately does not lend much to any specific model type's layout for that time frame.  The GGEM was a 2.5 day ... impossible to conceive historic snow event that would probably all but shut the region down until some kind of unilateral outside response saved lives... Ranging to the NAVGEM, which by default is much lighter....   

 

Probably something in between as the old cliche goes, but in this case, persistence combined with as yet to change pattern (though the bigger changes is still in question for beyond next week) really does provide a path of least regret ... namely, to provide band-width in folk's awareness' for something of a winter storm mid to late next week. 

 EURO was as well, I believe....perhaps more progressive...

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Yeah man.. I'm not saying the snowpack made it happen . I'm saying that was one of several components needed to help force this south and to not amplify. Plus I posted this yesterday, but we saw this even back when winter sucked this season of systems de amping as we got closer. I was kind of surprised yesterday that some of the gurus around here were so steadfast on a mild Rainer.

 

Yeah, my issue for bailing yesterday was the fact we were getting within the 72 hr window and it was going in the wrong direction. Sure there was time still for it to trend east and i coulda seen that happen in the short term, but we were trending from a 1000mb low tracking erie to burlington on the gem/euro and ensemble mean at that stage..

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Yeah, my issue for bailing yesterday was the fact we were getting within the 72 hr window and it was going in the wrong direction. Sure there was time still for it to trend east and i coulda seen that happen in the short term, but we were trending from a 1000mb low tracking erie to burlington on the gem/euro and ensemble mean at that stage..

Ditto. 

I didn't doubt it could trend se, as most have this season late in the game, but wouldn't have bet on this dramatic of a shift at this relatively late juncture.

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I still say the snow pack argument "component" is over used ...

 

It's statistically show (so is non-disputable fact) that temperatures can recover from deep below freezing values, to post melt degrees inside of 12 hours in situations where the return flow is deep layer, and there is no +PP to offer boundary layer resistance, snow pack or not.  ...Aside from the fact that I have seen it happen many times..

 

Over bare ground, a nascent cold load into NNE with a +PP would be quite effective at warm intrusion prevention in the low levels. 

 

That said, the only real assistance a snow pack gives along these continental cryospheric "edge" regions, is when there is in fact a +PP N of the region.  THEN, you get a positive feed-back in keeping llvs chilled.  

 

Snow pack "protecting its self" ...as it were, only takes place over very vast regions of geological space... such as the interior of Greenland.  But on synoptic meteorological scales... our local cryospheric region has virtually no power compared to an SW rushing air mass coming from a region of no snow pack, that is for all intents and purposes ...right over there.  

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Canadian never gets north of the CT/MA border above zero at 850 through the entire event, and yet somehow torches the surface up into the mid 40s region wide? I don't think so...

 

The same was true yesterday. Not sure I understand how the surface can be higher with all the snow pack. It's much more robust with QPF. 

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Canadian never gets north of the CT/MA border above zero at 850 through the entire event, and yet somehow torches the surface up into the mid 40s region wide? I don't think so...

 

I think it's trying to warm because clouds break out with relatively warm temps aloft, but be aware that models may bust a bit too high with srfc temps this time of year in these situations if it is cloudy.

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