General severe weather discussion

[stormdragonwx]

Thoughts on NC AR today? While I don't expect a repeat performance of what we saw in Iowa yesterday, im thinking things could get interesting later.

EDIT: Meso Discussion is out, Tornado Watch likely for said area. https://www.spc.noaa.gov/products/md/md0207.html

[Chinook]

It's possible that a large tornado has been going on near Paris and Clarksville AR. There is not an indicator that this is a confirmed tornado.

[Iceresistance]

Might see some action Next Week, the local TV mets are concerned for Next Monday.

[Quincy]

Signal for a couple of robust supercells developing over the Texas hill country and dropping toward the San Antonio area this afternoon. Thermodynamic profiles would favor large to very large hail growth. Wind profiles are not particularly favorable for tornadoes, given straight hodographs and minimal low-level SRH. 

Still, the combination of large CAPE and favorable deep layer shear, would expect at least a few significant hail reports near/just north of San Antonio. Will have to watch and see if the metro area is targeted, before storms weaken due to nocturnal stabilization. 

Edit: Austin could possibly be impacted as well, especially if there are any left moving hailers, as storms will tend to drop SE to S with time. 

[Ed, snow and hurricane fan]

3 hours ago, Quincy said:

Signal for a couple of robust supercells developing over the Texas hill country and dropping toward the San Antonio area this afternoon. Thermodynamic profiles would favor large to very large hail growth. Wind profiles are not particularly favorable for tornadoes, given straight hodographs and minimal low-level SRH. 

Still, the combination of large CAPE and favorable deep layer shear, would expect at least a few significant hail reports near/just north of San Antonio. Will have to watch and see if the metro area is targeted, before storms weaken due to nocturnal stabilization. 

Edit: Austin could possibly be impacted as well, especially if there are any left moving hailers, as storms will tend to drop SE to S with time. 

Watch out.  Day of my Engineering Economics final in May 1994, no hail on campus/downtown Austin, hanging out after test, I was enjoying actually seeing clouds bubbling up like a time lapse.  Movie that weekend in NW Austin, parking lot still full of automotive glass.  Not everyone knows about 'Monte Carlo' simulation, but in the oilfield, we generate a range of possible NPVs for a project, with a 10%, mean and 90% NPV.  Lot of unknowns in engineering, and in prices of oil.  Lot of beer in college on Friday or Saturday nights.  (Not both, engineers have to study)

[Ed, snow and hurricane fan]

5 minutes ago, Ed, snow and hurricane fan said:

Watch out.  Day of my Engineering Economics final in May 1994, no hail on campus/downtown Austin, hanging out after test, I was enjoying actually seeing clouds bubbling up like a time lapse.  Movie that weekend in NW Austin, parking lot still full of automotive glass.  Not everyone knows about 'Monte Carlo' simulation, but in the oilfield, we generate a range of possible NPVs for a project, with a 10%, mean and 90% NPV.  Lot of unknowns in engineering, and in prices of oil.  Lot of beer in college on Friday or Saturday nights.  (Not both, engineers have to study)

I teach high school math now since my last lay off, I'd have been laid off again for COVID.  On topic, -8 LIs, 40 knot deep shear (SPC meso discussion, straight hodos, wish TwisterData had TTs) but still a bit of cap in San Antonio.

[Quincy]

Estimating based on that sounding, TTI is approximately 51.5.

[Quincy]

Still some lingering surface based and mixed layer convective inhibition remaining downstream, but that should mostly be eroded by 4 PM. More than enough CAPE/shear for supercells, as evidenced by two ongoing supercells near Fredericksburg.

[Ed, snow and hurricane fan]

Screaming eagle cell in Coahuila.  I wonder if it is warned.

[Ed, snow and hurricane fan]

Just now, Ed, snow and hurricane fan said:

Screaming eagle cell in Coahuila.  I wonder if it is warned.

SPC used to have 'Cool Images', one was Mexican free tail bats being ingested by a tornadic supercell crossing the river.  Almost nobody lives out there (not many in parts of Texas like Balmorrhea, closer to New Mexico than Mexico, but also a desert town once hit by a tornado), but if they did, we'd have chaser images, I am sure.

[andyhb]

That wave ejecting on Friday definitely has some potential for the southern/central Plains. GFS is the most aggressive and is pretty classic looking both at the surface and 500 mb. Other models are a bit more subdued, need to watch the moisture quality.

[Ed, snow and hurricane fan]

Twitter starting to mention Monday.

[Chinook]

On 4/25/2022 at 1:11 PM, andyhb said:

That wave ejecting on Friday definitely has some potential for the southern/central Plains. GFS is the most aggressive and is pretty classic looking both at the surface and 500 mb. Other models are a bit more subdued, need to watch the moisture quality.

SPC now has an enhanced risk for Friday

 

[CheeselandSkies]

Interesting to see Monday starting to show as a potential setup...it caught my eye on the GFS a few days ago but the soundings were all totally capped.

[WhiteoutWX]

1 hour ago, CheeselandSkies said:

Interesting to see Monday starting to show as a potential setup...it caught my eye on the GFS a few days ago but the soundings were all totally capped.

“Cap” and “conditional” are quickly becoming the words of the 2022 severe season. 

[Chinook]

We are up to the point where the 00z convection-allowing models are covering Friday. Here is the 00z FV3 for Saturday 00z. The FV3 is usually quite a convection-happy model compared to others. I do expect some severe storms in Nebraska, probably some version of an MCS, and some supercells in Kansas and northern Oklahoma, east of a distinct dryline, with a huge moisture gradient.

 

[Quincy]

FV3 has an over-convect bias and will almost always initiate in even the more borderline/marginal setups. 

With that said, it does look like a delicate and potentially explosive setup just east of the dryline tomorrow from central Oklahoma into central Kansas.

Most CAMs show little to no convection, which does give more confidence that any development will probably be isolated. Given the orientation of the shortwave and wind fields, shear vectors are perpendicular to the dryline. Thermodynamic profiles are very favorable, with a capping inversion that should prevent convective initiation for most of the afternoon. (Diverging from earlier model runs that were erupting storms by 20-21z)

The NSSL highlights an uncomfortable potential scenario, with one lone supercell forming over central Oklahoma late in the afternoon.

Differing from some previous events, the warm sector looks thick enough to support any sustained storm for several hours, assuming that a storm can initiate.

I still remain skeptical about CI with southward extent across Oklahoma, but it’s still plausible. 

[nwohweather]

9 hours ago, Chinook said:

We are up to the point where the 00z convection-allowing models are covering Friday. Here is the 00z FV3 for Saturday 00z. The FV3 is usually quite a convection-happy model compared to others. I do expect some severe storms in Nebraska, probably some version of an MCS, and some supercells in Kansas and northern Oklahoma, east of a distinct dryline, with a huge moisture gradient.

 

I would target Wichita tomorrow if I were out there. Seems like there's going to be enough lift tomorrow kick off some storms through that cap, and there is some serious wind aloft and moisture being pumped into the region with dews in the mid to upper 60s. I'd lean that late tonight/tomorrow morning we see a MDT risk as the ingredients in play do favor a strong tornado threat

[CheeselandSkies]

1 hour ago, Quincy said:

FV3 has an over-convect bias and will almost always initiate in even the more borderline/marginal setups. 

With that said, it does look like a delicate and potentially explosive setup just east of the dryline tomorrow from central Oklahoma into central Kansas.

Most CAMs show little to no convection, which does give more confidence that any development will probably be isolated. Given the orientation of the shortwave and wind fields, shear vectors are perpendicular to the dryline. Thermodynamic profiles are very favorable, with a capping inversion that should prevent convective initiation for most of the afternoon. (Diverging from earlier model runs that were erupting storms by 20-21z)

The NSSL highlights an uncomfortable potential scenario, with one lone supercell forming over central Oklahoma late in the afternoon.

Differing from some previous events, the warm sector looks thick enough to support any sustained storm for several hours, assuming that a storm can initiate.

I still remain skeptical about CI with southward extent across Oklahoma, but it’s still plausible. 

The bolded was what burned my chase on 5/26/21. I gambled that the CAMS being relatively subdued with convection/UH in west-central/SW KS was a positive thing for chase quality. I ended up on that skeletal LP northwest of Scott City; after it was clear to me it wasn't going to intensify (and in fact was doing the opposite), I broke for additional cells SW of Dodge City which suffered a similar fate by the time I reached them. I don't recall capping really being thought to be a big event-breaker leading up to that day. Was there something else at play?

[Quincy]

18 minutes ago, CheeselandSkies said:

The bolded was what burned my chase on 5/26/21. I gambled that the CAMS being relatively subdued with convection/UH in west-central/SW KS was a positive thing for chase quality. I ended up on that skeletal LP northwest of Scott City; after it was clear to me it wasn't going to intensify (and in fact was doing the opposite), I broke for additional cells SW of Dodge City which suffered a similar fate by the time I reached them. I don't recall capping really being thought to be a big event-breaker leading up to that day. Was there something else at play?

I remember that day well. There was an intense morning supercell up by I-70 that went nuts and led to some of the best early day elevated supercell structure in recent memory. 

My fate was similar to yours. 

I pulled some obs and data. Most of the activity was confined to near the warm front/thermal gradient. 18z DDC sounding didn’t show much capping at all. At first I thought maybe it had to do with a weakness in the winds around 500mb, but I’m not sure if that was a prominent factor. There were severe storms even farther south in the Texas panhandle, where large scale forcing was weaker and 500mb winds were even less favorable. 
https://www.spc.noaa.gov/exper/archive/event.php?date=20210526

[Windspeed]

CSU 4km WRF..

[andyhb]

TTU WRF also has a couple of intense supercells moving across northern OK later tomorrow afternoon. Seems most of the WRF based guidance is pretty bullish on tomorrow's prospects regarding CI on the dryline, although longevity of the storms still is TBD. Seems like the KS stuff may struggle if it moves into the more stable air too quickly, while any OK storms may have a longer runway of favorable conditions should CI occur that far south.

[MNstorms]

Um ok GFS calm down. Last GDPS run is agreeing more with the GFS as well that next week may be interesting.

[MNstorms]

SPC now has these areas highlighted.

On Saturday, the models are in better agreement, with a narrow
   corridor of moisture returning northward into the central Plains.
   Thunderstorms will be possible along the western edge and on the
   northern end of the stronger instability, in parts of central and
   eastern Nebraska Saturday evening. Forecast instability and
   deep-layer shear appear strong enough for a severe threat. But there
   is considerable spatial uncertainty and the magnitude of moisture
   return is questionable. For this reason, will hold off on a 15
   percent contour at this time.

   Model differences increase on Sunday, with some solutions moving a
   shortwave trough across the central and northern Plains, while
   others maintain southwest mid-level flow in that same area. The
   models are in better agreement concerning moisture return, with a
   moist and unstable airmass in place by afternoon from northeast
   Oklahoma into north-central Missouri. Under that scenario, severe
   storm development would be likely along the western edge and at the
   north end of the stronger instability. But that would be dependent
   upon the timing of a shortwave trough. Due to the magnitude of
   instability that is forecast and potential for a shortwave trough to
   impact the region, a 15 percent contour is added for parts of the
   central Plains and lower to mid Missouri Valley for Sunday.

   ...Monday/Day 7 and Tuesday/Day 8...
   On Monday, the models are again in reasonable agreement concerning
   moisture return in the central U.S., with the richest airmass of the
   season advecting northward into parts of the lower to mid Missouri
   Valley. With a potential for strong instability, surface dewpoints
   in the lower to mid 70s F, and a shortwave trough in southwest
   mid-level flow, will add a 15 percent area also for Monday over
   parts of the lower to mid Missouri Valley. The same potential is
   forecast on Tuesday by some models solutions, but due to increased
   uncertainty on Day 8 at the furthest out range, will hold off on
   adding a severe threat area.

[Torchageddon]

On the CFS dashboard the chiclets are getting feisty with a rare 3 day red-x streak for nearly 4 runs - with some dark reds every other day before said period. It sniffed out that memorable TX day earlier this spring (Taylor) 11 days out. I've been watching that May 8-11 period for a while now.

If there was ever a time to get a bingo on the SPC dashboard this was it, surprised and disappointed Broyles didn't outline due to a lack of large-scale ascent those Days 7-8.

The first dark red-x 372-396 hours before May 11-12:

We'll see how close it was to the outcome.

[Powerball]

 

[yoda]

There were 2 tornadoes in Eastern Washington on Friday night in the Spokane area 

https://forecast.weather.gov/product.php?site=LWX&issuedby=OTX&product=PNS&format=CI&version=2&glossary=0

[Powerball]

 

[Powerball]

 

[Powerball]