2023 Mid-Atlantic Severe Wx Thread (General Discussion)

[yoda]

Pretty good day for the region and into AKQ CWA for severe weather reports, SLGT definitely verified

[Eskimo Joe]

36 minutes ago, yoda said:

Pretty good day for the region and into AKQ CWA for severe weather reports, SLGT definitely verified

Indeed. Was fortunate to have a tour of SPC back in April and spoke with their director. SPC has made tremendous advances in outlook and watch box verification. Thoroughly enjoyed the visit.

[Kmlwx]

38 minutes ago, yoda said:

Pretty good day for the region and into AKQ CWA for severe weather reports, SLGT definitely verified

Indeed - SPC placed that slight risk in the right spots! 

[87storms]

Hopefully, we can get some sun to fuel the next round tomorrow, but it looks like Thursday has more in the way of t-storm potential.

[high risk]

54 minutes ago, 87storms said:

Hopefully, we can get some sun to fuel the next round tomorrow, but it looks like Thursday has more in the way of t-storm potential.

      Tomorrow is a low overcast, seasonably chilly day with steady rain arriving - there isn't even a hint of instabilty.  Agree that convective chances increase Thursday and ramp up further Friday.

[87storms]

      Tomorrow is a low overcast, seasonably chilly day with steady rain arriving - there isn't even a hint of instabilty.  Agree that convective chances increase Thursday and ramp up further Friday.

Yea looks like one of those raw, straight off the Atlantic precip events incoming for tomorrow. Hopefully things get more spicy later in the week. I’m just glad the weather is getting interesting again.

[Eskimo Joe]

3 hours ago, 87storms said:

Hopefully, we can get some sun to fuel the next round tomorrow, but it looks like Thursday has more in the way of t-storm potential.

Not too impressed with Thursday. After some AM rain, looks potentially mostly cloudy with hit or miss rain.

[yoda]

Finally some talk of severe starting this weekend into next week from both SPC and LWX

[Kmlwx]

40 minutes ago, yoda said:

Finally some talk of severe starting this weekend into next week from both SPC and LWX

Yep! I see we got a bit of a mention in the D4-8 outlook. 

[George BM]

Yeah that Monday/Tuesday timeframe has one of my eyes.

[Kmlwx]

CIPS had a decent severe potential signal on the 168hr frame on the 0z suite. 

[csnavywx]

Monday getting my attention. Remnant EML + DPVA from big, broad trough setups are pretty reliable producers. Still a bit far out and daytime mixing and convective debris are always concerns, though favorably cool mid-level temps make it less sensitive to boundary layer moisture issues.

[Kmlwx]

49 minutes ago, csnavywx said:

Monday getting my attention. Remnant EML + DPVA from big, broad trough setups are pretty reliable producers. Still a bit far out and daytime mixing and convective debris are always concerns, though favorably cool mid-level temps make it less sensitive to boundary layer moisture issues.

You're in here talking dirty to the severe weenies...
 

Paging @Eskimo Joe - get us an EML and we can be sub-par on some other factors and still perform. 

[Eskimo Joe]

1 hour ago, Kmlwx said:

You're in here talking dirty to the severe weenies...
 

Paging @Eskimo Joe - get us an EML and we can be sub-par on some other factors and still perform. 

EML and dews over 70 degrees with NW flow. Those are our winnable setups.

[yoda]

Morning's AFD from LWX regarding Monday sounds tasty

By Monday, a trough digging across the Great Lakes and Midwest will
pivot toward the Northeast and Mid-Atlantic. Height falls and DCVA
ahead of the trough, modest diffluence aloft in the right entrance
region of a neutral to slight negative tilt upper trough, and low-
level convergence along and ahead of an associated surface cold
front will likely trigger showers and at least scattered
thunderstorms Monday afternoon into Monday evening. The 00Z
GFS/CMC/UKMET all show mid-level lapse rates of 7-8 C/km (though
note the 00z ECMWF is weaker around 6.5.7 C/km) attendant to a
remnant EML plume. These values are noteworthy for this part of the
country in late June, perhaps an indication of heightened potential
for strong to severe thunderstorms. Additionally, 850-500 hPa winds
of 30-40 kts with some low-level veering may lend to both low and
deep layer shear, which would aid thunderstorm organization.

Timing and strength differences remain, especially beyond Monday
night regarding just how quickly the upper trough and surface cold
front exit the region. Kept PoPs in the forecast during the
favorable afternoon and early evening hours Tuesday and Wednesday
with the front nearby.

[Kmlwx]

The CIPS analogs from the 0z suite had some decent ones mixed in. I saw June 4, 2008 lol

[Eskimo Joe]

Let's see how this looks on Sunday afternoon, but there's definitely some potential.

[Kmlwx]

12z CIPS guidance has decent severe signal at 84, 108 AND 132. Best threat window we've had all year. 

June 4, 2008 is now the top analog on the 84hr frame! (for our domain/sector)

June 1, 2012 is showing up in the analog mix at the 108hr mark as well - though not one of the higher analogs. 

[Kmlwx]

Impressive sim reflectivity signal on the 18z GFS for Monday afternoon/evening. 

[yoda]

ML Lapse Rates are nice too... some 8C/KM showing up

[high risk]

I had doubts about the timing of the system, but there seems to be some increasing agreement on better timing.    The wind fields overall still don't look great, but it's impossible to ignore several impressive ingredients that may be in place.

[yoda]

30 minutes ago, high risk said:

I had doubts about the timing of the system, but there seems to be some increasing agreement on better timing.    The wind fields overall still don't look great, but it's impossible to ignore several impressive ingredients that may be in place.

30-40kts of deep layer shear should be enough, though it would be nicer to see 40-50kts IMO

[high risk]

1 hour ago, yoda said:

30-40kts of deep layer shear should be enough, though it would be nicer to see 40-50kts IMO

         That's what I'm getting at.     The shear appears so far that it will be sufficient for severe, but with some pretty impressive analogs being tossed around, I would expect to see some much higher values.

[Kmlwx]

Latest GFS runs have backed off a bit on the quality of the remnant EML. 

That said - we do have a Day 4 15% outlook area from SPC for portion of the region. 

[09-10 analogy]

Hard to get robust lapse rates and shear, and timing, all aligned together around here. 

But we don't get day 4 outlooked by SPC too often around here, either (not that northern parts of the sub are). 

EDIT: Not that it means anything, but this has been an aberrant June, what with all the tornadoes in the South (when their peak is usually well over by now) and then the tornadoes in Texas the other day. (I read somewhere that Texas hadn't had an (E)F4 after June 10th until this year, with Matador almost certainly being (E)F4 at least.)

[mappy]

Mark was liking Monday on twitter last night. 

[Kmlwx]

12z GFS suggests best mid-level lapse rates go mostly south of DC. But sim reflectivity panels still look excellent - damn impressive for a model that isn't the short range/higher res stuff

[yoda]

Pretty decent soundings from 12z NAM at range - 78 hours till the end at 84

[Kmlwx]

I'm going to sound like a broken record - but we have tossed around this discussion in the past - anecdotally I remember a lot more "solid squall lines" in the 90s and earlier 2000s and severe events since then have seemed to be more shorter line segments or more spotty.

Interesting that some of the analogs have had a lot of 1990s events in the mix - and that looks like a pretty long/solid line portrayed on the GFS. Again - just me with my pointless musings. 

[yoda]

6 hours ago, Kmlwx said:

12z GFS suggests best mid-level lapse rates go mostly south of DC. But sim reflectivity panels still look excellent - damn impressive for a model that isn't the short range/higher res stuff

Still pretty impressive on the 18z... few hours later though