The March 5-7 White Lion Obs/Nowcasting Thread

[Bob Chill]

Lessons learned for next winter: models are far from infallible, especially on the fringes of winter. People here say it all the time, but models are tools, not answers.

I think a lot of factors mixed in here. Although there was plenty of poo-pooing about it here yesterday, I can't help but think if we'd been a few degrees cooler yesterday, the precip starts earlier and accumulates at least marginally faster overnight. The ocean likely was also simply too warm, and with a marginal airmass when the coastal transfer happened, it was too much to overcome.

East of the fall line was going to have problems but if the storm evolved as advertised even after snow was falling, it would have been much much different. Even DC supported snow till late in the game as it was.

[Ger]

To this day, I swear I was robbed of a good 5 to 6 inches of snow that was melting on contact -- even with a base on the ground -- on the evening of Feb. 5 2010. And I was in elevated Upper Northwest, not even in the warmer Downtown. Few believe that, but from 8 to 10 p.m. on that night, while snow was piling up like mad in the suburbs, seemed the city was still too warm. Can only imagine what today would have been like.

I was in Brookland at the time. I am not sure if your location is more urbanized than mine at the time (Brookland has the feel and density of a suburb). However, I vividly recall that evening and, in Brookland at least, the snow had begun sticking from around 7:00 on. We lost several hours it had been snowing before 7, but little/nothing after.

[EastCoast NPZ]

BTW the nam now gives NYC 12"

 

Lesson learned for me:  ignore any and all future NAM model outputs. 

[Ronnie]

It was fun while it lasted in Mt Airy MD.. from earlier this afternoon

 

 

 

[Ger]

Trust me we aren't expecting much.

I don't want to be a hater, but if NYC gets 12 inches....it won't be pretty.

[pazzo83]

I don't want to be a hater, but if NYC gets 12 inches....it won't be pretty.

It's in the mid 40s right now in midtown.  Like I said, I'd be surprised if we get more than 5".  That said, N & E of here could get a lot more.

[Jebman]

The problem was not a lack of qpf.

 

We have plenty of qpf, its just that some of it turned out to be liquid. Like right now, a wind driven freezing cold rain in 38 degree conds. What snow we have is going fast. Even the sidewalk snow has been demolished, my shovels denied.

 

You go outside you get a faceful of cold moderate rain driven by wind gusts over 40 mph.

 

 

In retrospect I am glad now that I was foolish enough to stay up all night. A lot of prudent folk went to bed at midnight, got a good sleep, and were bright eyed and refreshed for Round Two and the epic comma head snows this afternoon. I didn't. I was a fool and stayed up til 945am this morning. I got to see all of the snow all night as well as that EPIC snow band at 920am. I finally went to bed at 950am and snoozed til 4pm. 

 

I woke up to a well formed comma head and truly epic, epic rains. Too bad I missed seeing the comma head form on the radar.

 

Yeah, we got demolished alright.

[RevWarReenactor]

I don't want to be a hater, but if NYC gets 12 inches....it won't be pretty.

 

 

If I had to bet I'd say they are going to feel the pain we felt today. Reading that forum is like "the NAM looks cold" sounds like us 24 hours ago. Look where that got us.

[H2O]

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

[Ian]

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.

[ravensrule]

It's in the mid 40s right now in midtown.  Like I said, I'd be surprised if we get more than 5".  That said, N & E of here could get a lot more.

I'd be surprised if you got more than 2".

[Ger]

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)

[Ji]

Video of my backyard at 10am

http://moby.to/40u81r

[vinylfreak89]

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.

[psuhoffman]

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. 

[psuhoffman]

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. 

[vinylfreak89]

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.

[psuhoffman]

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. 

[Bari]

best storm troll i've seen in a long time, lol

[psuhoffman]

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. 

[WxUSAF]

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. 

[Bob Chill]

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.

[nj2va]

It's in the mid 40s right now in midtown.  Like I said, I'd be surprised if we get more than 5".  That said, N & E of here could get a lot more.

 

Who cares what NYC is getting?

[Stormhunter]

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. 

[WxUSAF]

Hmmm...a spotter had 2" in Columbia.  Should I just take it?  I did have .6" of QPF. 

[H2O]

Those are some long ass posts telling us how it didn't snow when all I need to do is look outside and know

[nw baltimore wx]

Those are some long ass posts telling us how it didn't snow when all I need to do is look outside and know

 

I've still got a one inch white sponge outside.  So glad this winter is over.

[SeminoleSullivan]

I get the same feeling hanging around here right now that I get when I'm at a funeral.

[Bob Chill]

Those are some long ass posts telling us how it didn't snow when all I need to do is look outside and know

I shoulda just looked at my zipcode and calender before this even became a digital threat

[clueless]

JB video was hysterical.

I watched a bit of local tv. Ouch. Lots of explaining to do. What a tortuous winter.