MN Transplant

Excellent wintry day with the snow blowing around.

That’s strange. They should send out an explanation when something like that happens.

Yup. And usually I’m leery of the ASOS precip totals in snowfall, but that was almost dead on with mine (2.8”/0.20).

Another factor in the model discussion is the ratios. This was a very high ratio storm around here for us. None of the models really do that well, even using Kuchera. DCA/IAD/BWI were all under .25” of precip. The GFS was by far the worst model in this regard.

2.8” new on 0.20” precip in Falls Church, so good ratios. I’ll push back on some of the model commentary. At least around here, the GFS had way too much precipitation. The HRRR was more realistic except for a few runs last night that went too dry. The NAM and Euro were the best on QPF in the DC area.

Probably virga to start. Only 0.01" precip by 11pm.

NAM 3km looks fine. Everyone N and W of a CHO to Annapolis line looks like 0.25"+ QPF. Pretty intense band at 1-3am.

40.2 and the snowpack is struggling.

edited!

16z HRRR will be the first run that has the entire storm within the 18 hours. The 15z is a minor improvement on the 12z, taking the <0.10" QPF amounts off the table.

Nice vertical velocities on the GFS

12z HRRR has the dead zone near 95. <0.10" QPF in parts of Fairfax and MoCo. This seems like an extreme solution, but puts a lower bound on the event.

Down to 3.5" here on the ground. Undisturbed areas look fine still, but lots of green around footsteps and under trees. Interesting temperature trace last night in parts of our area. My brother's station west of Frederick went from 27 to 45 in less than an hour when the inversion broke. Meanwhile I just bounced between 37 and 40 all night.

NAM 3km is 0.3-0.4” for many of us, mostly within 4 hours.

That is a map of wind speed. Deformation aloft indicates rising motion. That's what we want.

The snow on the trees 48 hours after the storm is amazing.

Euro ~0.21" for DCA.

Sounds good, everyone posted snow maps and not QPF.

I said it with the last storm and I'll say it with this one - the mesoscale models have some value in their output of how the precipitation shield may look. We can all agree that the GFS, and later the Euro, hit the past storm correctly, but they just didn't have the resolution to nail the sharp backside. That's the value of the mesoscale models. So, if the mesoscale models are hinting that there may be some lee side of the mountains effect, I'm going to pay attention to that even if we defer to the globals on track and intensity.

Forget the snow maps for a minute, the total precip numbers are pretty well in line with each other: For a spot near DC: 12z HRRR: 0.26" 12z NAM: 0.13" 12z NAM 3k: 0.23" 12z GFS: 0.25" 12z FV3: 0.2-0.3" 12z RGEM: 0.2" 00z Euro: 0.2" 06z Euro: 0.2-0.3" Throw out the NAM for obvious reasons, and it is a 2-3" snowfall.

I literally put "freshen up the snowcover" in my notes for that event.

Going to eat a lot of snow over the next 24 hours. Temps staying up near 40 in the overnight hours prior to the front tomorrow.

HRRR has a realistic scenario where there is a relative min east of the mountains and before the low strengthens.

Same, the cars cooled fastest and had the most accumulation. Ground-level snow board was relatively low compared to elevated surfaces.

No drizzle here