wxmeddler

Those things are explosive. Bet it sounded like a cannon when it went off.

RD-QVP from KLWX of the Storm so far. Very prominent warm nose. I'm not sure what the lower enhancement of the ZDR is. Snow Growth? If it is, our "flurries mixed in with the sleet" will be coming to an end shortly.

Dumping sleet in this band. Sounds like pouring sand out like others have reported.

Dry Slot is all the way back in W Tennessee, we got a bit to go here folks.

KNHK (Pax River NAS) is reporting -FZRA. It begins.

Yeah now that I’m thinking about it; If we get FZRA it will be exactly like concrete with the sleet as the aggregates and the ZR as the binder to fill in all the pores.

I told everyone I know to stop shoveling at 8am. If you scrape the snow/sleet off, you’re just gonna make an ice sheet later. Better to have the snow be the pavement interface than Sleet / Freezing Rain concrete.

Could be some Freezing Drizzle and Freezing Fog through just before sunrise as well.

There hasn't been this kind of CAD Wedge / Storm combo in this region since 2007 (Valentines Day), and even then, this dwarfs that for the depth and strength of the cold air. You'd have to find some really old timers to remember when something like this occurred.

As I think someone previously mentioned, if you are seeing snow. That snow was formed below the melting layer (~8,000ft-ish). So sleet that you see formed above that, and flakes formed below. For you VA folks, if you stop seeing the tiny flakes, good chance you're gonna go to FZRA within a few hours.

To this point. Freezing Drizzle is a real concern of mine even after we get dry slotted. There is enough atmosphere above freezing but below the dry slot to develop drizzle which would then fall as FZDZ. Good Summary / Post

If the warm layer is thick enough to melt the entire snowflake then they’ll all be about the same size. Sleet doesn’t “grow”, so really no wiggle room from that 3:1 area.

Hi, yes. It was. Both the Towson and Baltimore boards were slightly under-calibrated. I went in and took the beginning depth manually and re-adjusted. They are reading closer to correctly now. Please keep in mind that the sensors are only reasonably accurate to +/- 1". Here is the Towson Time series where you can see I made the adjustment via the big jump at about 7:15a

That is the CAD Wedge. There lower CC returns aloft within the wedge, but it seems right now that the temp is dancing around 31-32 within the wedge at about 8fkt. Leading to rimed flakes but not a full sleet transition.

Sterling Balloon is up already this AM. 31 deg at 7500ft.

Good thump up above helped break through the dry layer:

Ceilometer in NE-DC showing the evolution nicely. Would expect flurries to start appearing in the district shortly.

Guidance was consistent that once the uber-dry layer between 3kft and 5kft got broken through it would begin with -SN fairly quickly. So not surprising we go from nothing for 6 hours then all the sudden a flurry breakout.

Not much so far:

Every single road today that I drove on between MoCo / PG / AA Co's were salted and brine'd to heck. What a waste of tax money, and unfortunate for our small streams.

It is public. I'm not going to share directly because it's a bit of a clunky site and I'm afraid to look at it wrong let alone let the hordes onto it.

Baltimore isn't much better.

Tough Nut so far

We're in for some real sh*t if that's the case. Most guidance gets the fall line and SE at or above +5C as early as 11am tomorrow. Would love to see those studies if you have the links. I don't recall ever having a situation where there is a +7 to -8 swing in a single profile in this area. That is some southern high plains ice storm levels of cold air wedging. We do not see this here.

Good Question. I made an example here of the general concept. In the images below I've "Unskew'd" the Skew-T so that temperature is now vertical line on the X axis. Y axis is height obviously. The only question to ask is which area / shape is bigger? The Red (Above Freezing) or the Blue (Below Freezing). In this profile the blue is bigger, and therefore Sleet would likely be the most dominant precipitation type. So what about this one? Red is bigger, therefore Freezing Rain would be most likely. In the real world of course there is more to consider like dynamic lift in banding, precipitation rate, etc. but it's useful.