high risk

A wind-driven MDT is certainly the type of event that might see the issuance of a PDS severe box. Curious to see how this plays out, with severe storms well-established already in western Michigan during the morning. The next box that gets issued out ahead of it might be PDS.

Thank you. I'm not aware of any correlation between the severe season and summer temperatures, but it's a great question. Some severe seasons are tempered by all of the flow being displaced north into Canada which usually implies a hot pattern. Some seasons like this one are tempered by anomalous blocking which kept a lot of people cool. And we all know that patterns can quickly break down. Looking at some of the longer range forecasts, they are showing a big ridge over the central U.S. and more troughing in the east (as you noted). This would imply fairly frequent frontal passages for us, with breaks in the heat, potential severe weather along the fronts, and maybe even some northwest flow severe events.

exactly. the entire SVR season has been ridiculously tame almost everywhere. there hasn't been a MDT for tornadoes since those April events in the southeast

Any threat in the DC-Baltimore area looks to be along and northwest of I-95 in Maryland, and the ARW2 and NAM nest are the models to hug. Haven't seen any HRRR runs get any convection of note into our region today, for what that's worth.....

The issue is that the best wind fields stay well west of here, which is why LWX talks about a threat west of the Blue Ridge That said, for those of further east, the wind fields aren't great but will be improving through Wednesday night. But the instability will be deceasing through that period, mitigating the threat of severe. There might be a period of overlap with decent shear and instability across northern VA early Wednesday evening. I am, however, thinking that people along and northwest of the I-95 corridor have a good chance of getting at least one round of northeast-moving heavy rainers with lightning later Wednesday evening.

Gonna bump my earlier post. Looking at the 00z guidance, there is a pretty healthy combination of cape and deep-layer shear progged for tomorrow afternoon. The limiting factor is downsloping and overall lack of convergence on the front, which explains the very limited coverage of storms in the guidance, but any storms that do form have wind potential (and perhaps hail potential) for sure. If later runs show greater storm coverage, it's a SLGT risk day.

We're obviously focused on the current day, but don't sleep on tomorrow. While the CAMs are not in agreement about whether there will be any storms, some guidance does (12z NAM nest, 18z HRRR....) bring fast-moving storms through on the front during the afternoon. Coverage would be limited, but the cape/shear combo is sufficient for a wind/hail threat in any storm that develops, consistent with the MRGL threat from SPC.

The HRRR Is better than you think. It's unfortunate that Tropical Tidbits shows only 1 km HRRR reflectivity, as the model rarely shows its best signals at that level. Pivotal Weather shows composite reflectivity, which always looks much better. (Composite will always be "hotter" than 1 km, but for the HRRR, it's usually a more realistic representation.) The composite reflectivity in recent runs suggests a lot of outflow interactions with potential for multiple rounds of storms well into the evening again.

I'm definitely down with the heavy rain threat later today. I'm not as excited about SVR potential (not that yesterday's SVR was off the charts, but the watch was a good one, IMHO) due to the shear being even weaker today, but the forecasted soundings still have a bit of an inverted-V structure, suggesting that a few local microbursts are possible.

and now the flash flood watch has been issued. events like this show the huge challenges with hi-res, short-range modeling......

getting drowned with this batch right now in southern Howard County with a lot of this batch still to move through. Watching the line along the I-81 corridor as well. Thinking that the recent dryness will prevent widespread flash flood potential but would not be surprised to see a FFW or two overnight.

This was always going to be a later event here, and that hasn't changed. Interesting now that the cell north of Harrisburg has a TOR warning, and the one near Gettysburg may have one soon.

for everyone talking this down, there is no doubt that if you require supercells or a big ugly bow echo (like in PA) yesterday to be validate a threat, it's not a day for that. but there will be convection moving through the area later (maybe most likely from DC and points north), and our forecast soundings have that inverted-V structure which favors a downburst threat (it's shown in the high downdraft cape values). Shear and instability are modest for sure, but the watch is totally justified, IMHO.

alarming, to say the least. But the HRRR and HiResWindow ARW2 still like DC and areas north.

time to invoke this forum's scale for level of interest by user. It won't be any sort of high end day for sure, but I'm still feeling good about some organized line segments with severe potential tomorrow.

yep. about 70.

Had a glorious view of that York cell from southern Howard County. Could see a fair amount of lightning within it too.

yes, but there is still some organization and a clear sfc cold pool. Deep layer shear isn't quite as good as in some other CAMs, but the inverted-V sounding structure will definitely promote robust cold pool formation. I think we'll wake up tomorrow in a SLGT.

The next few hours are when a drop in dew points would occur if it does. The HRRR was most aggressive with that southwest of DC - will be worth watching. Still 65 here. Also, the day 2 kept MRGL here, but the discussion specifically mentioned a potential upgrade for our area in later outlooks. I personally think there was enough in the morning guidance to give us a day 2 SLGT, but I'll defer to the experts

Yes. The new MD mentions potential back building into north-central MD. Very little guidance has a good handle on the ongoing convection.

It's not going to be a huge day, but most of the various CAMs show about 40 kt of deep layer shear and inverted-V soundings, so some organization of cold pools is quite possible. The explicit reflectivity solutions across the hi-res windows, NAM nest, HRRR do show some organization.

Agreed. The 12z CAMs continue the idea of fairly good coverage of storms tomorrow. Deep layer shear isn't awesome, but it's probably enough for at least scattered SVR. The updated day 2 will maintain the MRGL for sure, and I wouldn't rule out a SLGT.

agreed. if something can race south earlier than progged, and the instability isn't killed by lowering dew points, northern and central MD could still be in the game.

We didn't have too many CAMs back then. The NAM nest was running, and it whiffed badly on that event. The HRRR did ok, but it was experimental, and not many people saw it. A key for today will be dew points. The HRRR is most aggressive in mixing them out (downsloping factor?). Most guidance mixes them out to some extent but try to have them recover closer to 00z, especially across northern MD. I certainly can't disagree with everyone ready to punt today, but I'm not ready to close the book quite yet, at least for those of us north of DC.