high risk

Personally, I look at both the HRRR and NAM Nest as my go-to CAMs. The 3 Hi-Res Windows are lower on my list. The HRRR and NAM Nest both have their strengths and weaknesses. The HRRR has a big advantage in running hourly, and there are things it does to create a more accurate starting point (a sophisticated assimilation of radar data, heavy usage of surface obs....) The NAM Nest hasn't been updated in 8 years. The HRRR hasn't had a recent update but was last updated 4 years ago. In terms of biases with rainfall, NAM Nest tends to run wet, but the HRRR sometimes runs dry - might be microphysics, but tough to confirm. And the HRRR is very sensitive to the hourly updates, so its solutions bounce around a lot. The NAM Nest tends to be too cool with sfc temps, but it handles low-level inversions way better than the HRRR due to a better PBL scheme. And as noted earlier, the NAM Nest tends to overdo orographic precip due to a very sharp topography field that was put in to enhance winds over terrain. That's just a few things off of the top of my head.

2% TOR and 5% WIND for much of the area in the new Day 2 outlook. Probably not enough sfc-based instability to take advantage of the intense shear, but the threats are certainly non-zero.

We might actually get a good amount of rain (Wednesday night into early Thursday) AND have it hit 70 around midday Thursday.

As I noted in the other thread, we need to keep an eye on Thursday. There is growing model agreement that we'll enter the warm sector in the morning and clear out a bit, after the widespread warm advection rains and convection exit to the northeast. There will likely be some scattered convection from late morning into the early afternoon along the occluded front, and it will be in a strongly-sheared environment. The question is how warm we get. It's tough to destablize here in late October, and we'll need really warm surface temps to overcome lousy lapse rates. It will get very warm in southeast VA and the southern Eastern Shore, but will that really warm air be advected this far north? So far, the experimental RRFS is the most aggressive, with temperatures reaching 70 in DC and an area of 750-1250 surface-based CAPE covering much of the area.

Some sneaky severe potential Thursday midday or early afternoon as we enter the warm sector. At the least, some elevated convection late Wednesday night into Thursday morning seems likely.

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.