2022 Mid-Atlantic Severe Wx Thread (General Discussion Etc)

[high risk]

1 hour ago, Eskimo Joe said:

Saturday has good potential if the timing works out.

         I think that the timing is fine, but most of the CAMs have very few (at best) storms in our area.    I'm not totally sure what the negating factor is, but I think that the orientation of the system will lead to strongly veered flow in the low levels, which as we know is subsidence in our area and mixed-out moisture.    Barring some changes, it's going to again be a central PA event.

[Eskimo Joe]

 

[SnowenOutThere]

Line of storms to the west looks good

[MDphotog]

The storms, at least here, are very quick pulses, nothing severe, just lots of rolling thunder and some quick rain.

[yoda]

Wednesday evening maybe?

[yoda]

@high risk Any chance for some severe tonight into tomorrow?  I see MRGL risk nearby... maybe some WF fun late tonight?

[George BM]

22 minutes ago, yoda said:

@high risk Any chance for some severe tonight into tomorrow?  I see MRGL risk nearby... maybe some WF fun late tonight?

I'm thinking maybe some of us may hear thunder later this evening w/ some small elevated CAPE. The surface looks too stable for anything severe-wise up in these parts though areas, mainly south of Fredericksburg, could see some enhanced wind gusts and/or a low-level meso w/ convection rooted closer to the surface there. 

[high risk]

38 minutes ago, George BM said:

I'm thinking maybe some of us may hear thunder later this evening w/ some small elevated CAPE. The surface looks too stable for anything severe-wise up in these parts though areas, mainly south of Fredericksburg, could see some enhanced wind gusts and/or a low-level meso w/ convection rooted closer to the surface there. 

        I think you nailed it.     Most guidance shows an enhanced area of convective cells moving through the area during the mid to late evening, but the surface layer is really stable.    Lapse rates are garbage, so even elevated CAPE will be small (as you noted), and the sfc-based CAPE to our south will be limited too (hence only a MRGL to our south).     I agree, though, that there may be just enough elevated CAPE to get some lightning, although I'm far from sold on the potential.    The thunder potential might perhaps be a big greater much later tonight, as the low-levels warm a bit, and lapse rates slightly improve.    Coverage of cells will be limited, but anything could put out some lightning.

[southmdwatcher]

Southwest VA down through western NC and upper SC are overperforming this evening with severe storms. The warm front is north of Richmond now.

[WeatherShak]

        I think you nailed it.     Most guidance shows an enhanced area of convective cells moving through the area during the mid to late evening, but the surface layer is really stable.    Lapse rates are garbage, so even elevated CAPE will be small (as you noted), and the sfc-based CAPE to our south will be limited too (hence only a MRGL to our south).     I agree, though, that there may be just enough elevated CAPE to get some lightning, although I'm far from sold on the potential.    The thunder potential might perhaps be a big greater much later tonight, as the low-levels warm a bit, and lapse rates slightly improve.    Coverage of cells will be limited, but anything could put out some lightning.

[NorthArlington101]

Really loud cloud-to-ground lightning in Charlottesville - nice early season storm.

[NorthArlington101]

might have a hint of rotation? Not expecting a warning but think I see something.

[NorthArlington101]

might have a hint of rotation? Not expecting a warning but think I see something.

[mattie g]

That storm posted above was pretty damn loud last night.

[George BM]

A lot of the lightning bolts from the I-95 storms last night were strong w/ peak currents between 50-100 kiloamps (some were over 100kA). 

Generally the vast majority of bolts produce peak currents of roughly 20-30kA give or take. 

[vastateofmind]

1 hour ago, George BM said:

A lot of the lightning bolts from the I-95 storms last night were strong w/ peak currents between 50-100 kiloamps (some were over 100kA). 

Generally the vast majority of bolts produce peak currents of roughly 20-30kA give or take. 

Interesting. Since the storm blasted me out of sound sleep and I observed/heard most of it, my casual obs were that it was more intense than storms from recent memory (last fall, summer). I was awakened, in fact, about 20 minutes before the worst of it hit -- the lightning was pretty intense in advance of the real gametime overhead.

[yoda]

Southern part of LWX CWA down by EZF outlooked by SPC for Day 6

 

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0359 AM CDT Sat Mar 26 2022

   Valid 291200Z - 031200Z

   ...DISCUSSION...
   Medium-range model guidance remains in good agreement that a
   shortwave trough will move through the Southwest into the southern
   Plains on D4/Tuesday, before then trending towards a more negative
   tilt while moving through the Lower/Mid MS Valley and into the OH
   and TN Valley on D5/Wednesday. This shortwave is then forecast to
   continue northeastward through the Mid-Atlantic on D6/Thursday.

   Severe potential will accompany this shortwave as it progresses
   eastward, beginning across the southern and central Plains on
   D4/Tuesday. Strong moisture advection will precede the shortwave
   across the Plains, with low 60s dewpoints potentially reaching
   through eastern OK by Tuesday evening. A well-developed EML atop
   this returning moisture will support moderate buoyancy. A sharp
   dryline will intersect with this buoyancy to support thunderstorm
   development, with the mesoscale ascent along the dryline aided by
   strengthening large-scale ascent. Supercell wind profiles will
   support updraft organization and the potential for all severe
   hazards.

   The severe weather threat will continue into the Lower/Mid MS Valley
   on D5/Wednesday. Buoyancy will be weaker here than farther west on
   D4/Tuesday, but both low- and mid-level flow will be very strong.
   Current guidance suggests mid-level flow within the now negatively
   tilted trough will exceed 100 kt at 500 mb. A large area of 60-65 kt
   850 mb winds is expected. This will result in large, looping
   hodographs that support organized severe thunderstorms. Convective
   mode will have a large influence on the dominant severe type, but a
   discrete mode would result in the potential for long-lived
   supercells. Even if the mode is more linear (which appears most
   likely at this point), the strong wind fields support the potential
   for numerous severe gusts as well as embedded QLCS circulations.

   The shortwave will likely lose some definition by D6/Thursday but
   remain strong enough to support thunderstorms as it interacts with
   the moderately moist and buoyant environment across the
   Mid-Atlantic. Strong wind fields are expected to support organized
   severe thunderstorms across portions of central VA and central NC.

   Variability (both run to run and between models) increases after
   D6/Thursday, limiting forecast confidence and predictability on
   D7/Friday and D8/Saturday.

   ..Mosier.. 03/26/2022

[Eskimo Joe]

To follow up on the previous post by @yoda

[NorthArlington101]

12 minutes ago, Eskimo Joe said:

To follow up on the previous post by @yoda

I figured that had to be unusual. Decent day for me to chase, if I so chose, though Virginia is probably not the place for a novice to chase, even just for structure. I'll have to see what it looks like.

[Eskimo Joe]

 

[high risk]

Definitely keeping an eye on Thursday, as there is good model consensus for a very strong system in the east.     Given the cold air mass in place early Wednesday, it's obviously uncertain how far north the higher theta-e air will reach Thursday, but a slightly slower system (as suggested by the Euro) would increase our chances of seeing appreciable CAPE.

[yoda]

LWX AFD from this afternoon mentioned the threat

By late Thursday, a strong cold front will approach the area and may
introduce some heavy showers and even thunderstorms during the
afternoon and evening hours on Thursday. 40-50 knot bulk shear
coupled with 200-300 MUCAPE values are being observed for this
system in some of the guidance. This, coupled with >60 meter 500 hPa
12 hour height falls have triggered a slight risk for severe weather
on Thursday. Main hazard for the event looks to be damaging winds
along with isolated large hail. Main locations of interest where
instability parameters look more favorable would be south of I-66 in
central VA. SPC has a D6 15% outlook for severe weather, the first
of its kind across portions of the area. Behind the cold front
Friday morning, colder/dry airmass will build in for a brief
period.

[yoda]

00z GFS soundings for 18z THUR to 00z FRI look decent 

[yoda]

SPC has outlooked the majority of the region for severe on Thursday (Day 5)

 

[WeatherShak]

SPC has outlooked the majority of the region for severe on Thursday (Day 5)

 

Noticed DT sounded an “Aleet” this morning.

[Eskimo Joe]

Thursday into Friday could really be interesting.

[yoda]

11 minutes ago, Eskimo Joe said:

Thursday into Friday could really be interesting.

@Kmlwx

Early Step 4 alert? 

[yoda]

06z GFS soundings are quite decent... ML lapse rates are 6.5C/KM to 7.0C/KM at 21z THUR

[Iceresistance]

@yodaYou beat me to it by 3-4 hours

[Eskimo Joe]

1 hour ago, yoda said:

06z GFS soundings are quite decent... ML lapse rates are 6.5C/KM to 7.0C/KM at 21z THUR

We'll see how this week progresses, but we tend to do well when we have cooperative mid level lapse rates. This seems to aid updrafts and overcome the litany of local mseoscale features that mess up convection.