MN Transplant

I think they got about 7" like what was reported. I got 8.5" and they had less precipitation than I did, which was particularly important in the snow period before the sleet. The colors don't mean anything other than more or less snow/sleet.

Roger - my sleet was 2:1

I think I'd go in-between. Most of us will be single digits, with the favored spots (IAD, Manassas in VA) having a better chance at 0.

How much snow/sleet do you think DCA actually received?

Assume we are tracking the cold in this thread. 24.0 and the wind is picking up. Models are all over the place on lows tonight, but the favored areas may make a run to 0.

12/5 - 1.9" 12/14 - 1.3" 1/26 - 8.5" Total - 11.7"

Rooting for George now!

My pro-tip from this morning is to pull out the garden shovel. The plastic snow shovels are no match for this mess.

Funny thing is that it was kind of a calculated number. At no point did I ever have more than ~7.7” on the ground. A lot of compaction with the weight of the sleet on top. But I also couldn’t find any place that would legitimately give me more than 3.5” of sleet. So, yeah, a 2:1 ratio on the sleet.

I’m going to call it 8.5” total. Insane precip at 2.33”.

It isn’t N/S, it is E/W, and it is insanely sharp. I popped up to 21 but have fallen back to 18.

I don't think I've experience 40:1 outside of the upper Midwest, but it is at least in the realm of possibility. We effectively did 20:1 in early December this winter and that wasn't a crazy airmass. It is just fluff at those ratios.

The ~2" of sleet that I just shoveled was heavier than the 5" of snow that I did this morning. It makes sense water content-wise, but it is still wild. 18.0 degrees and rising slowly.

The surface temps are running well below guidance, at least IMBY (16.4°) which makes me wonder if the cold layer is going to hold on long enough to reduce the ZR chances.

Still just 14.4°. It looks like I got another 0.5" from that mix between 7-8:30am before going over to full sleet. So, sitting at about 5.8", with 5.5" snow and 0.3" sleet. One thing, as everyone has noticed, is that the sleet is very dry. I'm guessing that the depth of the cold layer helped to completely refreeze the sleet without some of the residual "softness" that normally makes it sticky. Might end up being beneficial for travel over the next few days, ZR-dependent.

I'm not seeing any plain rain on the GFS except for over east of the Bay. Sometimes the error isn't the model itself but how the individual providers display it.

It won't be long. Vis rapidly increased here and I'm mostly sleet.

NAM was shockingly low with the precip, but the thermals were good. Still technically snow here, but it is getting louder as it is icy/rimed.

5.0” on 0.56” precip. So we scored on the precip and the ratios were bad. As is evidenced by my mesh outdoor furniture not collecting snow at all with tiny snow grains. (Actual snowboard location in fencing above dog).

Watching the temp/DP come together at 13 degrees is much more fun than 34.

HRRR continues to advertise a later flip than the NAM. More like 15z/10am in DC. Rates are always important, but it’ll kill us if we lose the column by 7am.

Looking great! Edit - Johnson City, TN is the line right now

TDWR base scans are 0.3 degrees and the WSR-88Ds are 0.5. So, closer and lower to the ground is normally best. However, the 88Ds are more powerful. I still defer to them in light snow.

The Canadians finally thawed. 12z GDPS seems healthy precip wise. Guessing a 14Z changeover after maybe 0.7"? 12z RDPS either had something wrong with the run or with the transmission. Not on Pivotal, but it is partially on College of Dupage. Same 14z changeover timing. No precip amounts available, but looks healthy from the precip rate/type maps.

I have just enough knowledge of this to be dangerous, but high risk can correct me. Models have a dynamical core and various physics packages. About a decade ago NOAA/NWS decided to try to align all of the operational models with a single dynamical core. The FV3 was chosen but there have been some problems with it when it is run at finer convection-allowing resolution. So, the alternative was MPAS (model for prediction across scales) from NCAR. I know that NSSL has been testing out MPAS a lot and that one may end up being the dynamical core. One of the problems with MPAS, though, is that it is computing-hungry compared to FV3. So, NOAA is weighing pros and cons.