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The March 5-7 White Lion Obs/Nowcasting Thread


Ji

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1.27 liquid so far. At least the models got that right

Euro seems to have been best up here at least. Don't really see many verified purple obs this far north like the American models had.

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After today's epic bust, I'm feeling nostalgic about the early to mid-2000s. An era of busts!!!

I remember looking at radar during the Jan. 2005 event, trying to pivot the moisture stream in a way that was both realistic and kept D.C. snowing. A short time later the warnings were cancelled, ignominiously. And I added one more failed Miller B to my list (The List of Failed Miller Bs)

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the block won out with this one. It helped contract the precip toward the low more than you'd normally expect. The dynamics were crazy, just much closer to the storm than would normally be the case. Going in to this storm, I had thought the days of model busts were pretty much over, but this storm proves this is not the case. Heavy reliance on the models, ignoring small scale discrepancies  and lack of good science led to these busts. When I saw those megabands form to the east on some of the small scale models, I knew something was up. I accounted it to model error, but I was wrong in the wrong direction. Those convective bands near RIC and on the eastern shore helped take energy away from the CCB and it mostly fell apart. This, combined with no real cold air source led to this disaster for the region. The positive side of this shows we have a lot more to learn, and the post mortem on this should help progress the science further. I now know the simple idea of taking a blend of all the models is a bad idea, and when models show different a evolution so close in its important to examine the differences and figure out why, rather than discounting them or just saying "normal variance" and blending.

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Even up here this was pathetic.  Started good, got a quick 5" from the initial WAA surge in a fast burst like was predicted but then it all fell apart.  Once the low stalled and started to transfer the precip became spotty and light and from about 8am on it was 35 with light intermittent snow and even some rain mixed in up here.  None of the bands from 8am on were more then moderate, and nothing close to being able to recool the boundary layer and overcome the March heating.  In the end I have about 3" of slush on the ground right now.  It seems the globals that had the storm go through a messy phase and reorganization period were correct, and there is a HUGE difference between getting 1" qpf at 36 degrees and 1.75 and 33.  I have a nagging thought about if climate change has made it harder for our area to cash in on these marginal setups.  Seems we have had several chances lately where the setup was good but the temperatues just did not work for us, in the past those used to work out ok once in a while. 

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the block won out with this one. It helped contract the precip toward the low more than you'd normally expect. The dynamics were crazy, just much closer to the storm than would normally be the case. Going in to this storm, I had thought the days of model busts were pretty much over, but this storm proves this is not the case. Heavy reliance on the models, ignoring small scale discrepancies  and lack of good science led to these busts. When I saw those megabands form to the east on some of the small scale models, I knew something was up. I accounted it to model error, but I was wrong in the wrong direction. Those convective bands near RIC and on the eastern shore helped take energy away from the CCB and it mostly fell apart. This, combined with no real cold air source led to this disaster for the region. The positive side of this shows we have a lot more to learn, and the post mortem on this should help progress the science further. I now know the simple idea of taking a blend of all the models is a bad idea, and when models show different a evolution so close in its important to examine the differences and figure out why, rather than discounting them or just saying "normal variance" and blending.

I also think having a lack of real cold air is a contributing factor in not getting a more organized CCB away from the low.  When we have good cold it seems to add even more resistance to the moisture tansport and thus add to the convergence and intensify the banding.  WHen the airmass is marginal like this, you are relying completely on the dynamics of the storm and the CCB ends up more ragged and less consistetly intense away from the best dynamics. 

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I also think having a lack of real cold air is a contributing factor in not getting a more organized CCB away from the low.  When we have good cold it seems to add even more resistance to the moisture tansport and thus add to the convergence and intensify the banding.  WHen the airmass is marginal like this, you are relying completely on the dynamics of the storm and the CCB ends up more ragged and less consistetly intense away from the best dynamics. 

 

do you think that is more due to resistance to the moisture transport or due to the fact that when we have a real cold air source we almost always have a phase and therefore are shifting the confluence to the north allowing the moisture to spread out. After seeing this debacle, I am standing by my idea that while phases are complicated, they are still the best way for this area to get significant snow.

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IAD got .93 and BWI got .73. Unless it was 10 degrees outside and we had > 10:1 ratios, thats 9" and 7". Not exactly HECS. Both the GFS and NAM were way off with QPF. I think the euro was pretty close, but I have no idea how it verified with the storm formation. 

 

Especially since those precip totals are over 15 hours. There was no "thump" with this storm.

yea the initial WAA surge of precip just did not pack the punch models said.  It was in general 60 percent of what the guidance showed.  Not sure if the messy redevelopment process was the blame there or not.  After that models did hint that things would get messy with banding being more hit or miss, but because the initial band was pathetic the whole thermal profile was 2-3 degrees warmer then it would have been and this spelled disaster.  Either way, good point even if it was 32 degress totals would have been 7-10" across the area, and thats low compared to what the potential here was. 

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do you think that is more due to resistance to the moisture transport or due to the fact that when we have a real cold air source we almost always have a phase and therefore are shifting the confluence to the north allowing the moisture to spread out. After seeing this debacle, I am standing by my idea that while phases are complicated, they are still the best way for this area to get significant snow.

I don't think phasing is necessarily the issue, the Feb 6 2010 storm had a healthy CCB without much phasing.  I think more cold aids in lots of ways though, better snow growth so much higher ratios mostly.  If you have a cold thermal profile it can take a band that drops .25 qpf and turn it into 6" of snow.  Here is a scary thought, even in 2010, when we had the mother of all blocks in the middle of winter, it simply wasnt that cold.  All 3 of our HECS storms that winter were marginal at best and a few degrees warmer and we would have had issues even then, and that was with the most perfect setup I could ever imagine.  I am probably just bummed following such a wasted season, but it just feels like its so much harder to get cold and snow in marginal setups here.  Basically our marginal to bad winters have become just plain aweful, and the only time we can get decent snow is when the setup is 1 in 10 years perfect. 

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Euro seems to have been best up here at least. Don't really see many verified purple obs this far north like the American models had.

Euro was still too high.  And was actually still too warm at the surface during the day.  Probably too cold at 850.  All the models blew chunks on this.  NAM and short-range models just failed most. 

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PSU, what I find even more "off" about our snow climo is the lack of "normal" sized storms. Widespread 2-4 / 3-6 used to be a staple. Lately it seems like we need a big giant dynamic storm otherwise we are warm /wet.

We have cold periods every winter. Heck, half of Jan and all of Feb were cooler than norm this year. But we can't line up modest storms anymore. It's becoming too common to call coincidence. I don't think it can all be blamed on nina's. Ninas don't mean it can't snow. Stj miller A's are near impossible but not all the other ways we can get a widespread minor 2-4.

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yea the initial WAA surge of precip just did not pack the punch models said.  It was in general 60 percent of what the guidance showed.  Not sure if the messy redevelopment process was the blame there or not.  After that models did hint that things would get messy with banding being more hit or miss, but because the initial band was pathetic the whole thermal profile was 2-3 degrees warmer then it would have been and this spelled disaster.  Either way, good point even if it was 32 degress totals would have been 7-10" across the area, and thats low compared to what the potential here was. 

i'm just below ski liberty, 2 miles above the MD line.  We got between 8 and 9 inches.  I measured at 1030am.  After 1030am it was really a non event.  The snow was light to sometimes moderate after 1030 but the rates would not keep up with the melting as the case every where south and east. I agree if a tad colder ( 2 deg.) most would be in the 12" plus, If transitioning period to new surface low occured during the night time hours DC would have cashed in, just bad timing.  I normally do well up here. 

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Major Storm 6-12+ Bob Ryan going 90%... finally catching up!

 

Some random quotes

Bob Ryan just went with historic DC snow.

 

 

8-10'' all the way to the bay! Wow!

 

 

What a HUGE turnaround for lower southern MD!  They looked bleak just a few hours ago.  Awesome news for my family down there, and especially my brother who has plowing contracts in northern Calvert.  He's gonna make bucks tomorrow.

 

 

CWG gave tomorrow a 7 out of 10. Pretty good

 

 

Yeah, the RAP is monstrous for tomorrow. We'd all have a foot+ if it verified.

 

 

There is a death band coming

 

 

It is amazing how far south the 850 and 925 0C lines have ended up.

 

850: 

 

850mb.gif?1362549377930

 

 

925: 

 

925mb.gif?1362549272568

 

 

I think the mixing threat was overrated. I would think that DC/Baltimore should go wire-to-wire snow now.

 

 

Pretty awesome radar signature already. Its only going to get better as the ULL dives SE

 

15eh5iw.jpg

 

 

it's like feb 2010 all over again, but march

 

 

we're going to get so destroyed

 

i dont even have anything else to say for now

 

 

that and 2/6 were showing up almost every run on CIPS. it's like a 2/10 turning into a 2/5-6.

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Looking ahead to next winter season, I will continue to want to be in the modeled area with the greatest precip and cold temps in the runs leading up to gametime. My area really never was on any of even the really good runs, we were always modeled as on the edge, and that's exactly how it played out.  I have never really been comfortable with "north trend". 

 

On this one, as uneven as the models were on the edges, they did a great job identifying the areas that were likeliest to cash in. And that never really wavered. 

 

Bullseye with good temp profile, that's about the only way I ever feel comfortable. 

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The analysis of all the model runs was really good with this storm. We dissected them from top to bottom. Hashed out all the fine details. Rode them to the highest high even as snow was already falling.

The one thing we kinda missed was that they were all f***ing wrong.

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