WxUSAF

Just got home and measured 1.5”. Rockville definitely had more. Being west helped today as I sorta expected it would.

Lightened up in Rockville but a beautiful wintry scene

Hope it’s snowing like this at home in Columbia because it’s crushing in Rockville

About 1” on car tops in Rockville. Bit of a lull, snow down to moderate-light

View out the window from Rockville

Ripping in Rockville.

Looks like probably 1/4-1/2” on cars in Rockville. Temp at home in Columbia down to 33 and all snow per Mrs WxUSAF.

All snow in downtown Rockville. Car tops and mulch whitening.

Using my red tag, I deduce a cold front has passed my house

Was 41F with heavy rain when I left Columbia at 645. Started mixing with sleet on Rt200, all snow and sleet with a temp of 34F when I got to the Rt200/I270 interchange. Same in downtown Rockville where I am for my daughters rock climbing competition that was foolishly not cancelled.

47/46 with light rain.

Blizzard warning issued for the Blue Ridge in VA

Based on turn Super Bowl halftime show, Fiddy could use a drop of fiddy

45.0/40.5

Red!

Storm threads are going to be unreadable

The 200km grid point spacing they use for plotting also seems like a poor decision

You rang?

Sweet! North side of my yard is in the @Ellinwood blue! South side is eating grey. Got to move the snowboard tonight…

More seriously, I like this 12z 3k NAM more than any previous meso runs for MBY. I noticed last night on the super long range hrrr, that it focused a wave of heavier precip through the metro corridors around 12-15z as cyclogenesis intensified to our south, but had it as snow. Earlier NAM runs had that as rain for us, but this NAM finally has it as snow as well. I think that feature is pretty critical to getting accumulation in the metros and lowlands below the fall line. If it’s ripping fatties and 31-34F as advertised, it will accumulate. If that feature is rain and it only turns to snow with that broad diffuse backside anafrontal precipitation, I’m a lot more skeptical of daytime accumulation outside the rural areas.

I’m going with the Kuchera 12:1 daytime March snow ratios

Odds for my yard: Trace or more: 75% 0.1” or more: 40% 1” or more: 15% 2” or more: lolz

For comparison, forecast Saturday 12-18z temp drop at Baltimore: Euro: 41—>33 GFS: 50—>32 GGEM: 45—>31 3k NAM: 43—>32

It doesn’t mean there won’t be cold air outbreaks again, just that they are rarer and less potent then they would have been 20-50-100 years ago. Take any daily temp anomaly threshold you want: +/-5F, 10F, 20F whatever. Look back over the last many years and compare how often you get that level warm anomaly vs cold anomaly. Warm always wins. You can look at this winter as an example. I’d have to double check, but I don’t think there were any -20F or greater daily departures at BWI in DJF. But there was like ~8 days with +20F. And yes yes, UHI exists, but UHI doesn’t take a “normal” day in rural/suburbs to +10 or +20 at the airport.

That’s explicitly December-February