high risk

Pleasantly surprised to see some lighting strikes over northern Virginia

MRGL for most of the area which seems fair. Guidance is now in very good agreement that a strongly-forced, narrow line of heavy showers will race across the area during the evening: 9pm or so in the western burbs, 10pm in the DC-Baltimore area, and over the Bay by around 11. Wind fields are intense with some low-level shear, but instability will be negligible. Lightning therefore seems unlikely, and while winds will be gusty, severe gusts will be difficult to achieve. That said, I still can't completely rule out lightning or a few higher end gusts, and it's also possible that we end up with a tornado warning for someone for a brief couplet.

Your timing is off. The image you showed is for 9pm. Guidance has the line reaching the Bay by 11pm.

We're now into the range where we can start to see what this looks like in terms of hi-res simulated reflectivity. Both the NAM Nest and HiResW FV3 at 60 hours have an intense line to our west. We'll need a speed-up to boost severe potential locally, but a strongly-forced convective line will likely cross the entire region after dark. Any severe threat, or even lightning potential, will be low due to a loss of diurnal instability, but the dynamics will ensure that both threats are non-zero. And again, if this speeds up by 3-6 hours, the threats for lightning and severe will ramp up accordingly.

Tough to do severe here (from non-TC events) in mid October, but Sunday evening has some potential, especially if we look at the ECMWF solution of a deepening surface low over western PA. Instability is always a limiting factor at this time of year, and the timing of the system isn’t perfect, but it’s a strong trough with good wind fields.

Seems to be setting up a regional model vs global model battle. Good to see multiple CAMs in the 00Z suite give much of us at least 0.5" out of this event.

Definitely a camp of solutions that has a bit of a SW--> NE strung-out low solution for Sunday instead of a consolidated storm along the coast.

If you had said that the models had major disagreement and inconsistency all week, you would have been correct. But you wrote that the "models had nothing about this until now". That is spectacularly and embarrassingly wrong. You can read discussion about this being a legitimate threat in the medium range as far back as Monday.

That isn't even remotely true.

Small line of showers, seemingly right along the front. Winds have really picked up.

I don't consider that the "local area", but to each his own. Western MD has been consistently proved to get a significant rainfall from this event, and it has played out. The model QPF for the DC-Baltimore corridor is notably less, but there will be a corridor that jackpots over 0.50". Let's hope that ends up being a wide corridor. edit: and OF COURSE, the NAM Nest comes in way wetter for everyone within seconds after I type my comment......

We need to set reasonable expectations for overnight. A number of CAMs suggest that there will be a narrow WSW-ENE swath of just over 0.50" somewhere between Alexandria and Baltimore, but much of the local area will be fortunate to see 0.25".

Huge uncertainty for the weekend persists. Cool temps and gusty northeast winds seem fairly likely, but whether we get a soaking, nothing, or something in between is completely unresolved, although it does appear like the potential for a significant QPF event is waning.

It wasn’t consistent, but even before Saturday, there were some ECAIFS runs last week that showed the coastal threat. I remain thoroughly impressed by what the ECAIFS can sniff out well before the physics-based models catch on.

You've noted several recent cases in which the ECAIFS led the way in identifying a threat, and this is likely to be another example.

If there is going to be a period of more widespread showers, it looks to be very early Thursday. Otherwise, there will be some big winners with the scattered convection each day (especially Thursday), but it doesn't look to be particularly widespread.

Oh, what the hell! Let's fire up the SVR thread for perhaps its last hurrah of 2025. MRGL for tomorrow - the shear/instability combo isn't great, but I could see a few decent wind gusts. Will be very happy with thunder and heavy rain. The CAMs today mostly favored DC and points south, but the HRRR has kicked off the evening suite by favoring generally north of DC.

The simulated radar products from the CAMs for the next 2 days look more like what I'd expect to see in July instead of late September.

Woke up to a heavy shower around 3am or so and found a gloriously unexpected 0.15" in my gauge this morning.

Now that we're in CAM range, what really stands out to me is that this is going to me much more of a showery event than the rain shield I was expecting.

It's pretty clear that there will be a tight gradient on the northern side of the precip shield Tuesday-Wednesday. For those of us north of DC, the question is whether we're in the decent amounts.

Seems to be a growing likelihood of a midweek coastal low to bring most of our area at least some rain. Details are obviously still completely unresolved, but it's on a number of deterministic and ensemble systems.

Radar filled in gloriously after 10pm. Got 0.36” and am thrilled about it.

Yes, the tonight/tomorrow rain chances are sneaking up on us fast.

Interesting trend in some of the evening guidance to slow the exit of the clouds and showers on Sunday. The HRRR is the slowest, with showers not exiting the DC area until after noon and temps staying in the 60s all day with clouds. The NAM Nest and HiResW ARW2 both keep shower chances around through much of the morning but still get sun by midday. HiResW FV3 gets the showers out early, and clearing arrives quickly.