high risk

I can report that over here in Howard County, we don't have as high of reflectivity values as over Montgomery, and it's still absolutely pouring

while we're clearly not going to get the Sunday soaking that some of the guidance had been advertising, I think it's going a bit far to suggest a sunny afternoon. Most of the forecast soundings and simulated satellite products I've seen have clouds (and perhaps some light rain or drizzle) persisting well into the afternoon. But I certainly hope I'm being too pessimistic.....

https://wof.nssl.noaa.gov It's a hi-res ensemble, effectively run on-demand. You select a regional domain of interest and initialize it with new assimilation techniques to try to get the best initial conditions (environmental parameters and ongoing precipitation). The longer term goal is to have a system like this be good enough so that warnings can actually be issued by forecasts from the WoF instead of having to wait for radar signatures or ground truth.

Probably not Thursday and Friday. Still potential for huge soakers, but the weaker steering currents argue against widespread coverage. The weekend could be a different story, with a very favorable upper pattern and tropical moisture still in place.

Definitely. The ground is already very wet in parts of the area, there could be more storms later tonight, storm chances are good tomorrow and maybe Friday, and we then have to deal with the weekend.

I would say that it does, although I would not be surprised is there is some very weak rotation on the cells tonight, as there is some very modest curvature in the hodographs tonight.

overnight convection? the CAMs say maybe; the radar is really lighting up to our southwest

the PWs are really impressive, and earlier HRRR runs looked wet and suggested backbuilding, but that model has really backed off now.

certainly some chance of SVR this evening and later tomorrow, but I'm really starting to like the look for late Monday. NAM nest has an impressive connective signature in an environment with some shear. My biggest concern, though, is that the model looks slow with Isaias, so we could have a much wetter environment Monday than progged (and more of a flash flood thread than a SVR threat)

I'm not writing it off, but I'm not very excited right now. Far more interested in a potential PRE on Monday.

I have to admit that I wasn't paying close attention to tomorrow, but the HRRR and the Hi-Res Windows all some some impressive cells across northern VA later Saturday. Wind profiles have some definite directional shear, although there is probably too much weakness in the speeds in the lower levels to have a robust TOR threat. Slight risk seems completely justified to me.

actually, the deep layer shear needed for an organized severe threat is overall lacking today, which explains the lack of a slight risk. that said, I do think we'll see a few isolated severe warnings later today.

very pleasantly surprised to get a heavy shower. All of the guidance I had seen today had this activity dying out well before reaching the I-95 corridor.

I'm not ready to buy in to heavier rain making it back to the I-95 corridor, but I'm definitely not ruling it out. The NAM nest is certainly most aggressive, but there is some support from other CAMs for the precip bands extending further west, although even those solutions make it clear that the NAM nest is too fast. It's also worth noting that the GFS tends to not generate sufficient precip on the west side of east coast storms, although there is more evidence for that with winter storms than with tropical hybrids.

Watching the 5th good cell today miss me by a couple of miles. Still stuck at a trace.

Yeah, this is comedy watching the whiffs here today. HRRR still says I get soaked in a few hours. Debating whether to water the garden.....

Exact same situation here just down the road. I rarely get pissed off at the weather. Right now, I'm really pissed off at the weather.

looking out my window here in Howard County, it looks like the atmosphere is trying to initiate locally

really need some patience. The CAMs were not forecasting an early show here. It will take time for the PA/NJ complex outflow to surge west and southwest, with development building along it back into northeast MD. There is still a legit question of whether there will be decent coverage in the DC/Baltimore corridor, but IF it happens, it won't be for several hours (and could even be an evening show).

No doubt that the eastern shore is the best place to be for organized SVR later today. For those west of the bay, we need the outflow to surge further west. It's worth noting that both the NAM nest and HRRR don't have too many storms in the DC area, as they both mix out the dew points a bit this afternoon. (HRRR is most aggressive.) Some of the other CAMs (the ARW2 of particular note) do not mix out the low-level moisture as much, as they have more coverage of storms west of the bay.

outflow made it all the way down to southern Howard County. Really nice!

Somewhat brief but torrential here in southern Howard too.

Thanks again for posting this. Tropical Tidbits has now corrected their plotting error as of the 18z cycle today.

great catch! If you look at the Tropical Tidbits 24h precip maps, it looks pretty clearly that the site is accidentally aggregating 24h totals, so I think it's a plotting error (or an error in the grib2 files) and not a new "biblical wet bias" in the new version.

12z NAM nest and HRRR both develop storms Saturday in the local area. Instability is limited, and shear is marginal, but there will be a lot of downdraft cape. Personally, I'm not very enthused, because the low level air will be so dry, but I'm ok with the MRGL. Sunday could be good if we lose the ugly warm mid-level temperatures being progged.