high risk

morning CAMs also seem to be locking in a cell or small complex developing this afternoon over north-central VA and rolling southeast on the west side of DC during the mid-late afternoon hours. This is a bit further north and east than previously shown. This activity has the best opportunity to be sfc-based, with some wind potential.

yeah, I feel good about convection in the area during the evening. The soundings just don't look great, though, in terms of any severe potential. but the soundings ahead of the late night line show lapse rates and most unstable cape values that are not common around here. That's why I think that this is our best chance on the Maryland side for severe (hail).

The late afternoon storm threat looks to be on the west side of DC, but I like the chances for a lot of us to hear thunder in the early evening. The time period to watch, though, may be the 3-6 am period, when multiple cams show a line racing southeast across the area. It will be elevated, but impressive lapse rates will be overspreading the area, leading to some severe hail potential.

Looking at the CAMs, it looks like round 1 develops as a weakening Ohio Valley MCS undergoes intensification in central VA early Tuesday afternoon and rolls southeast. For the rest of us, our best chance appears to be in the evening hours, when storms that initiate in the late afternoon over eastern OH move southeast towards us. (A few solutions have another batch of storms rolling through from the northwest in the early morning hours Wednesday). Lapse rates look good, so I like our thunder chances - the potential for SVR will depend on how warm we get Tuesday afternoon and stay into the evening hours. While I like our thunder chances with that event, I'm less excited about SVR potential, as I think they'll be elevated, although I suppose I can't rule out some hail.

definitely. and SPC today mentions the mid-Atlantic for both Wednesday and Thursday. A quick check of the morning guidance suggests that the timing is off here for good potential on both days, but there is certainly time to adjust the setup.

Some decent forecasted reflectivity structures in some of the CAMs for later this afternoon, especially in the HRRR and especially over northern VA. Instability is meager, but freezing levels are low, and low-level lapse rates are good. Would not be surprised to see a little small hail and perhaps even a lightning strike or two in the strongest cores.

Realizing that this isn't really the right local forum for this question, but since the correct forum isn't very busy and there has been plenty of discussion about this case in this thread, does anyone have a good feel for why the Jonesboro violent tornado occurred? SPC's outlook didn't have hatched probs in AR, and the MD they issued a little while before the event mentioned the possibility of only a few QLCS tornadoes. The mid-afternoon LZK sounding had decent a decent wind profile, but low-level shear was very modest. The environment in northeast AR didn't seem particularly special. Was there a rapid improvement in parameters late Saturday afternoon that wasn't captured? Or did the storm find a boundary to latch on to?

These soundings aren't too bad - wind profiles in the lowest 1 km are a bit weak but still fairly good. Kmlwx has a good analysis - the problem is that not much guidance shows robust convective development in this area. The one way we could sneak into a better event is if the NAM nest is correct about the slow progression of the warm front. If a cell interacted with that boundary, it could get interesting.

wow! low-level directional shear is lacking a bit, but the low LCLs and impressive low-level cape would make that a volatile environment. Even if we chop off a few degrees from the T and Td, it's still scary.

for us on Sunday, right now the forecast soundings look terrible with limited instability and weak low level flow. It's also unclear whether the cool air will erode over the northeastern half of this subforum. Gonna need a huge improvement in the setup to give us anything of interest.

1500 is probably enough cape to handle that kind of instability, especially given that it's not "tall, skinny" cape, and there is enough low-level instability for good parcel accelerations. The forecasted soundings keep getting better, and SPC now has a day 2 MDT which looks justified. Still questions about evolution of elevated convection earlier in the day and resulting impact on how far north the warm front can get, but areas just south of wherever the warm front ends up look primed.

The problem seems to be that the sfc high to our northeast is moving out faster than was being shown, leading to the sfc winds shifting from north in the morning to southeast by the end of the day. In the NAM and GFS, that allows the sfc dew points, which start the day in the low teens, to recover to the low 30's by evening. That certainly won't get the job done. If we can somehow hold in northeast sfc winds for more of the day, we'll be able to keep the drier air in place and potentially reap some wet bulb benefits when the precip arrives.

NAM nest still shows that the front will sink back to the southwest later today and cool things down for those northeast of DC. HRRR seems to be coming on board.

While it's an obvious long shot, and I won't try to pretend otherwise, this is a chilly and very dry air mass that will settling in over us on Sunday. (The GFS shows dew points dropping perhaps into the single digits early Sunday). So IF the low can track south of us and we can get precip in here overnight Sunday, that could work for some of us.

There has been discussion about this line over in the severe thread. It's been going for a couple of hours now.

There are some small hints of it in the previous HRRR runs, but it's overall really tough for a model to get this, as it has to get the initial forcing and cold pool dynamics. Forecast soundings show a strengthening unidirectional wind profile and some downdraft cape......

This line is producing. I've seen a few events like this over the years, with a fast-moving line of low-topped showers requiring warnings. Will be interesting to see how far southeast they survive.

not at all saying that this will end up as a severe event, but the radar is supposed to look empty right now, regardless of whether we get severe. The guidance shows storms breaking out over central WV in the next 2 hours and then racing east-northeast.

lots of signal around 7 or 8pm, but a general 6-9pm range should cover it. overall severe threat seems fairly low but not non-zero, consistent with the SPC outlook. But lightning would be a nice early March bonus.

you have a very legit chance of seeing convection, for sure.

pretty stong agreement among the CAMs this morning that the threat later today is all north of the DC Beltway, and depending on your model of choice, it could well north.

right. because the HRRR is 5-8 degrees warmer.....

18z HRRR has a sfc-based bow echo moving across the areas north of the DC Beltway early Tuesday evening. It's an outlier solution in terms of having much warmer sfc temps than other guidance, but IF it were correct, it would be a SLGT risk day.

This post is spot-on. I can see why they didn't have any thunder marked around here on the prelim day 1, but the 12z guidance has clearly shifted towards more favorable parameters AND explicit convective signatures in the simulated reflectivity. It warrants a general thunder outlook in the new day 2 for sure, and it's honestly not that far off from a MRGL.

well, crap. Those got added in pretty late, so I guess that LWX had to look pretty hard to find them but in seriousness, the Culpepper reports don't totally surprise me, but the Fairfax reports do. I didn't see anyone in this forum report strong winds inside of the Beltway.....