December 29-30 storm.

[Wonderdog]

These snow events of the past week remind me of the old days (60's;70,s). Back then, you could count on the gradual progression of winter storms making their way west to east and finally reaching the mid atlantic and further north in the first week of January. I suspect that we will have our legitimate shots of a few winter storms in January; especially past mid-month, after a slight warmup in the second week of January. I also don't believe the modeled strength of next week's high pressure. I wouldn't be suprised if we get lucky next week (obviously I have nothing to back up that feeling). I think Mr. Chill is right when he said that there haven't been many high pressure systems that have been as strong as modeled. They seemed to vacate the northern tier of states pretty quickly in December.

[WEATHER53]

temps were never going to be an issue...if we had started at 5am with 0.25" precip we would have done ok

Yep. I posted earlier in thread that we needed 1/2-1" before 9am, trying to accumulate after rain with snow not getting going until 10am is very tough circumstances to overcome.

[PhineasC]

i cant go above T with a straight face. too wet.. 2 degrees lower on starting point could have been huge

That was the reason we were optimistic for a 4 or 5 AM start. This stuff now would have been snow on snow. Once we got the snow hole the scenario was totally different.

[Ian]

That was the reason we were optimistic for a 4 or 5 AM start. This stuff now would have been snow on snow. Once we got the snow hole the scenario was totally different.

Just a good reminder that complicated setups are complicated. When you can fail in 10 ways there's a good shot one will happen. However, the idea that it would be changing to rain around here seems to have been wrong. It's rate dependent of course but looks like most of the transition zone will stay snow till it winds down.

[Yeoman]

Time to move onto the next non-event for DC

[PhineasC]

These snow events of the past week remind me of the old days (60's;70,s). Back then, you could count on the gradual progression of winter storms making their way west to east and finally reaching the mid atlantic and further north in the first week of January. I suspect that we will have our legitimate shots of a few winter storms in January; especially past mid-month, after a slight warmup in the second week of January. I also don't believe the modeled strength of next week's high pressure. I wouldn't be suprised if we get lucky next week (obviously I have nothing to back up that feeling). I think Mr. Chill is right when he said that there haven't been many high pressure systems that have been as strong as modeled. They seemed to vacate the northern tier of states pretty quickly in December.

This week gives me some hope for winter. These were all marginal situations that managed to over-perform in many spots (or in the case of this latest one come back from certain disaster) in a month that has been a blowtorch and mostly written-off. Last winter these would have all been drizzle or nothing but cloudy skies. Still 2.5 months left to get something substantial in here.

[PhineasC]

Time to move onto the next non-event for DC

And you'll be right here lurking in the threads tracking it and hoping for a dusting.

[Sparky]

Yeah, the delayed start time changed the whole dynamic for those living on the edge of the mixing zone.

[Yeoman]

And you'll be right here lurking in the threads tracking it and hoping for a dusting.

Who said I wasn't?

[Yeoman]

Yeah, the delayed start time changed the whole dynamic for those living on the edge of the mixing zone.

There wasn't enough moisture available that it would have made much, if any, difference.

[PhineasC]

you guys north and west were never a big concern--i told winterwxluvr to go to bed.. it was really just the 'transition zone'. it's nice to see snow but the sfc temps still suck considering the outcome.

Well, accum is one thing, but several folks were talking about rain-snow mix or a change to rain. I think it was right in the end to dismiss those concerns. The soundings were marginal, but this is pretty near peak seasonal time to make it work and the airmass was decent with minimal winds. I think people over-think soundings or extrapolate based on reports from folks next to large bodies of water. It also doesn't help that our main forecasters here live next to the DC airport or on the Bay.

[PhineasC]

There wasn't enough moisture available that it would have made much, if any, difference.

Well, yeah, that's the point. Had the snow hole not opened up over area we would have started as snow at 5 AM and this would all be gravy on top of 1-2 inches (less in the cities). Just goes to show we focused on the wrong bust factor for the past few days.

[87storms]

well this was a snoozer. hope next week's cold helps us end this decent snow drought in dc and vicinity.

[The Dude]

you guys north and west were never a big concern--i told winterwxluvr to go to bed.. it was really just the 'transition zone'. it's nice to see snow but the sfc temps still suck considering the outcome.

Yup. We've had a couple hours of pretty snow to watch, but zero accumulation to speak of (the best I've found is a bit of slush right above the windshield wipers).

[usedtobe]

Well, accum is one thing, but several folks were talking about rain-snow mix or a change to rain. I think it was right in the end to dismiss those concerns. The soundings were marginal, but this is pretty near peak seasonal time to make it work and the airmass was decent with minimal winds. I think people over-think soundings or extrapolate based on reports from folks next to large bodies of water. It also doesn't help that our main forecasters here live next to the DC airport or on the Bay.

I've been mixed all day. not pure snow so again it depends on where you live. Most of us thought you'd see snow and so would guys out towards Leesburg. Except for the timing, I think the storm was pretty well handled except for the 2-4 over Ian's house that someone forecast.

[usedtobe]

Grass is starting to turn a hint of white tho it's still mostly melting faster than falling. We might eke out a 0.1-0.2 or so with this last bit.

So did either BWi or IAd measure enough for the SPI to verify?

[MN Transplant]

snow's just not staying consistent enough here to do it.. keeps weakening a bit on approach

Back end kind of just collapsed on you. Bummer.

I'm going to go back on what I said earlier, and record 0.4". I guess I was biased by looking out my back window instead of where I normally measure.

[Yeoman]

should be a solid trashcan lid whitener

Fail

[blizzardmeiser]

I've been mixed all day. not pure snow so again it depends on where you live. Most of us thought you'd see snow and so would guys out towards Leesburg. Except for the timing, I think the storm was pretty well handled except for the 2-4 over Ian's house that someone forecast.

All snow here in northeast Md.

[PhineasC]

well this was a snoozer. hope next week's cold helps us end this decent snow drought in dc and vicinity.

cold/dry, warm/wet

Never forget it.

[Ian]

Well, yeah, that's the point. Had the snow hole not opened up over area we would have started as snow at 5 AM and this would all be gravy on top of 1-2 inches (less in the cities). Just goes to show we focused on the wrong bust factor for the past few days.

These are tricky "lessons" to carry forward though. It all depends on the handoff IMO. I was never really that worried about the column all that much even IMBY for some reason. If it's really close, as you note, this time of year will do it more often than not I think. I didn't see many models starting anything good before 12z here.. Even that might have been more marginal than we think given the potential bottom of temps based on the DP combo etc. It might have still started as rain before heavier came in so we would have still had wet ground to deal with. Maybe if it started at 4 it would have been better.. who knows.

[Ian]

Back end kind of just collapsed on you. Bummer.

I'm going to go back on what I said earlier, and record 0.4". I guess I was biased by looking out my back window instead of where I normally measure.

I don't think I can really count anything other than a T. There was maybe 0.1" on cartops but that's a bit sketchy.

[Bob Chill]

Yeah, we spent a long time talking about temps but they have been mostly a non-issue. It wasn't like we were 60 before the storm like sometimes happens. It has been cold enough for the past week with a good sun angle situation. We probably should have been paying more attention to the dual-low structure sapping our precip. Some were talking about that, certainly (Bob Chill for one).

It bugged me the entire time. I wanted to be wrong but having 2 relatively equal strength lows that close together and there is no way to avoid a "lift neutral zone" and that stupid zone set up right overhead to rob us the pre-dawn snow. That was the dagger of sorts.

And weakening of one and strengthening of the other doesn't mean the coastal sucks all the energy and moisture from the dying low across our area either. They weaken and strengthen in their own space. I know you know this but many try to extrapolate radar in these scenarios and that's dangerous analysis. The weak spot in the middle (us) gets hosed no matter which way you slice it.

I was bearish yesterday at least. It never looked like things would go our way. It is what it is though.

[Ian]

So did either BWi or IAd measure enough for the SPI to verify?

Not sure. I'd have to guess IAD did looking at the surrounding area.

[clskinsfan]

I actually think the NAM did very well with this storm. I may have to stop bashing it so much. I still like the chances of something next week. The cold air is gonna be here and there and this map has the look of a decent over run event.

[PhineasC]

Nearly an inch on the deck.

[Ian]

you can't start at 38 degrees for a 90 minute event during the day with rate dependent precip type....a longer event (6-8 hr) with an evolution, and peak and banding, 32-34 would have been servicable once you got through that 1st 60-90 minutes and got a coating down and got the temps down for a bit....

Right. I'm just not sure we would have gotten much lower than we did regardless. Who knows. I don't think anyone particularly nailed it even if outcomes match some thoughts.

[usedtobe]

These are tricky "lessons" to carry forward though. It all depends on the handoff IMO. I was never really that worried about the column all that much even IMBY for some reason. If it's really close, as you note, this time of year will do it more often than not I think. I didn't see many models starting anything good before 12z here.. Even that might have been more marginal than we think given the potential bottom of temps based on the DP combo etc. It might have still started as rain before heavier came in so we would have still had wet ground to deal with. Maybe if it started at 4 it would have been better.. who knows.

I don't think the models ever forecast the column to be warm just the layer from the surface to around 950mbs and for this event, they were pretty clsoe to being right. Heck at 7Am, my temp was 37 so I would certainly have started as rain or sleet before any changeover no unless the precipitation came in at 4Am or so as I was 32.4 at 11PM but was 37 by 7Am and 38 by 8. The lack of CAD made this a different animal than the last one though if we had gotten .30" maybe temps would have been cooler because of the lifting, but then they may have been warmer because of the stronger warm advection.

I'm getting my last little snow burst.

[WinterWxLuvr]

It bugged me the entire time. I wanted to be wrong but having 2 relatively equal strength lows that close together and there is no way to avoid a "lift neutral zone" and that stupid zone set up right overhead to rob us the pre-dawn snow. That was the dagger of sorts.

And weakening of one and strengthening of the other doesn't mean the coastal sucks all the energy and moisture from the dying low across our area either. They weaken and strengthen in their own space. I know you know this but many try to extrapolate radar in these scenarios and that's dangerous analysis. The weak spot in the middle (us) gets hosed no matter which way you slice it.

I was bearish yesterday at least. It never looked like things would go our way. It is what it is though.

This was always a precip issue, for all but maybe those near sea level. That split line us up perfectly. If that ended up 50 miles further south, we'd have had precip much of the night.

We ended up better than I thought we would here. Seems like anything gives us a decent snow right now.

[Ian]

I don't think the models ever forecast the column to be warm just the layer from the surface to around 950mbs and for this event, they were pretty clsoe to being right. Heck at 7Am, my temp was 37 so I would certainly have started as rain or sleet before any changeover no unless the precipitation came in at 4Am or so as I was 32.4 at 11PM but was 37 by 7Am and 38 by 8. The lack of CAD made this a different animal than the last one though if we had gotten .30" maybe temps would have been cooler because of the lifting, but then they may have been warmer because of the stronger warm advection.

I'm getting my last little snow burst.

Yeah, I was sort of thinking about the lower levels though again I didn't seriously start looking till yesterday. And yeah I agree on the more precip angle.. may have ended up the same. As usual you rise among most of the pack for accum verification. But, these are good learning experiences for those with less knowledge.. Of course folks like Doug K are back patting but he was sort of wrong with how it came together it just ended up matching his forecast map.