WxUSAF

It can create confluence, so in a general sense, yes it can. We'll see if it does this time.

The 500mb and surface track didn't really change on the GFS. Maybe a slight north wobble at certain panels? But the cold/dry air push on the northern edge is stronger. That tightens the precip gradient, hence the reduction north of DC and same (or better) south of DC.

If you want to sweat the cold FROPA, the SPC mesoanalysis is good to follow: https://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=17# Can choose either "Surface" or "Winter Weather" and see where the isotherms are packed to tell where the front is located. Based on the wind shift, it's getting close to the metros in MD/DC and a bit farther north in VA.

60/56 at DCA with 1005.5mb SLP at 2pm. Feels like snow.

DCA streak of days above 22F looks to be in jeopardy!

Someone make an obs/nowcast thread. Need to track DCA temps and Pittsburgh pressure.

Dear God man, what’s Pittsburgh’s barometric pressure!?!?!!!!????

Let’s just say I’m going to be asleep and not reading the meltdowns in the obs thread when it’s 53F at DCA at midnight

Euro laughs at the NAMs and ICON. DC purple’d

Haven’t looked myself that it allegedly inched north relative to its 0z but it ain’t no GFS

Tommy T ain’t having it (much like a covid vaccine)

Cooper Kupp O/U yards receiving today against the ravens? 120? 150? 170??

Which is why expectations should be kept in check.

@CAPEliking a blend of the 12z GFS and 6z Euro for his yard. 15-20” seems reasonable

This storm seems primed to bring the HoCo-MoCo deathband out of retirement.

We could just lock all the threads until 6am tomorrow?

Mrs. WxUSAF got us a La Crosse model. Posted a pic in December Banter a few days ago. I wanted a Davis VP2, but hard to justify $700.

Well, more than that because your high today will probably be 63F

@mappyis politely humble and then will double DCA’s total lol

I tend to agree, but take a look at the cross section plot in my post from an hour ago. Clearly shows 2 areas with max omega in the DGZ. One north of DC in the colder air, one south with the frontogen max.

I bet the mean/consensus of today's 12z runs will be about where it ends up. The storm is forming now and the models are "seeing" the diabetic energy release.

Congrats on 17"!

Brand new weather station says 0.6" fell after about 730pm yesterday.

It's gonna snow! So what does this storm have going for it that we didn't appreciate 72 hours ago or before? (except @CAPE). 1. The increasing separation between yesterday's warm rain and the cold from that will pass through later today gives this storm room to amplify, while also giving the cold air just enough time to filter in ahead of it. Watch how the shortwave has gotten distinct from the cold front (indicated by the blue offshore and to our N/NE over the last few days: 2. With this increased separation, we are getting MUCH better dynamics to support a broad expansive precip shield. Beautiful positioning in the right entrance region of the strong jet streak over New England supports strong lift. The 500mb low is passing in ALMOST the ideal position. 6z GFS tweaked it back south every so slightly, but here is the 0z GFS which shows Position A for DC snowstorms: with a closed 500mb low passing along the VA/NC border: 3. Take a look at the strong 700mb (also at 850mb) frontogenesis (in the insert image below). This is basically a measure of where temperature gradients are strengthening and a proxy for strong vertical lift and thus heavy precipitation. It's focused near DC and just south, where things should be ripping 24 hours from now. The cross section shows the DGZ (between the dashed red lines) and the very strong upward motion within the DGZ through the region. Ideally, that DGZ would be a bit deeper, but we've seen far worse before. If the GFS is right, at around 12z tomorrow, we're puking dendrites all across the region. Ok, so what's working against this? 1. It's moving fast. Euro is <12 hours of snow in DC. GFS is a bit longer and GGEM even a little shorter than the Euro. There's just not that much time to snow. This is what happens in fast flow/unblocked conditions. 2. It's going to be 60F today. This is not a problem because 4 inch soil temps or some shit like that are too warm. No, it's just because we have 30F to cool down from! That just takes time, even with a strong FROPA like we'll get today. So, it very well may start even as rain briefly in DC and points south and/or it will be snowing with temps in the mid/upper 30s to start and take some time to cool down to freezing where it can accumulate more efficiently. But this is a very different situation than the anafrontal wave that this looked like 3-7 days ago. That's much more of a "cold chasing precip" sort of situation and we are not in the situation now. Still, freezer doors open tonight wouldn't hurt.

Rock solid rain forecast for VA beach.