Central/Southern Plains Severe Weather Palooza (4/29 - 05/05)

[Powerball]

At this point, there's fairly high confidence that there will be multiple severe weather episodes during this period. The most ominous days for a widespread severe weather outbreak appear to be Monday (5/2) and Wednesday (5/4), as a pair of strong shortwave rotate through the region around the base of an upper level trough and there will be sufficient moisture return

The main thing these systems will have going for them (that has largely been lacking with Plains severe weather setups as of late) is good directional *AND* low-level shear supportive of rotating supercells.

Timing and cloud cover, as usual, will be the main question marks when determining the locations that will face the highest risk.

Shortwave #1

Shortwave #2:

Shortwave #3:

[Powerball]

 

 

[Quincy]

FWIW, in regards to tomorrow…

18z NSSL WRF backed off of convective initiation (CI) in Oklahoma tomorrow. Latest 21z SREF also dropped CI probabilities to about 20% along the dryline. 

00z HRRR indicates that most convective inhibition (CINH) is eroded by 22z near the OKC metro area, but no storms initiate. This is thanks to 2m temperatures rising into the mid-80s, atop low to mid-60s dew points. It’s close… modify the forecast soundings for slightly greater boundary layer moisture (HRRR dry bias) and you’d probably get within 1-2F of reaching convective temperatures.

Let’s see how the rest of the 00z suite looks. 

[Quincy]

NAM/ARW suite doesn’t convect, but also shows a lot of residual cloud cover in Oklahoma, limiting daytime heating. NSSL still tries to pop a storm in north-central Oklahoma, while most other guidance shows nada south of the KS/OK border. 

Morning satellite and obs will play a big role in pinning down tomorrow’s threat. 

[Radtechwxman]

@Quincyhow do you feel about initiation on dryline in south central KS? TP is obvious play but looks to get messy quick and could get undercut by front

[Quincy]

Just now, StormChaser4Life said:

@Quincyhow do you feel about initiation on dryline in south central KS? TP is obvious play but looks to get messy quick and could get undercut by front

Analog guidance coupled with the trajectory of the nose of the upper jet would suggest better than 50/50 odds that a storm could form in south-central Kansas or possibly north-central Oklahoma. 

 

[Radtechwxman]

1 hour ago, Quincy said:

Analog guidance coupled with the trajectory of the nose of the upper jet would suggest better than 50/50 odds that a storm could form in south-central Kansas or possibly north-central Oklahoma. 

 

Thanks man! I appreciate your input! 

[CheeselandSkies]

Wind-driven moderate risk upgrade centered on the KS/NE border at 13Z. Wasn't really expecting that. If they were gonna go moderate I thought it would be 15% tornado/45% hail down in S KS/N OK. They did directly address this in the discussion:

 

Quote

...Central Great Plains vicinity...
   Multiple forecast scenarios are expected to unfold this afternoon
   and continue into tonight. Sufficient mesoscale confidence exists to
   warrant a wind-driven category 4/Moderate Risk along the NE/KS
   border, but not yet enough to include higher tornado probabilities
   farther south.

This is really the kind of day that the 10% hatched Enhanced is perfect for, IMO. In the old 3-tier outlook structure, there isn't enough confidence in sustained tornadic supercell development over S KS/OK for a 15% hatched moderate risk, but a 5%/slight risk doesn't really convey the extent of the hazards that would occur should any such storms get going.

[thunderbird12]

12Z HRRR is the odd model out, showing essentially no development on the dryline this afternoon. Of the other 12Z HREF members, the FV3 and WRF-ARW have development into northern OK, and the 3km NAM and WRF-NSSL have development all the way into southwest OK (and the 3km NAM all the way into northwest TX). Definitely a trend toward more dryline storms compared to the 00Z guidance. Still probably a close call either way as to whether storms go or not on the dryline. 

[Quincy]

HRRR is playing catch-up with surface moisture, as is often the case. Latest mesonet data shows widespread 65-66F dew points across central Oklahoma. Latest HRRR run tries to initiate a cell in north-central Oklahoma and I wouldn’t be surprised if future runs favor more intense convective development. 

My thoughts: Relatively high confidence of isolated supercells from central KS into north-central OK. Think a secondary area is favored for CI in southwestern Oklahoma, but still have questions about how intense/long lived any convection might be there. OKC isn’t out of the woods either. That 12z OUN sounding showed some thick CAPE profiles and steep lapse rates above the capping inversion. 

I won’t be able to update for a few more hours and by then, it’s almost game time. Stay safe today!

[Windspeed]

[Windspeed]

Norman...

[nwohweather]

I could see things absolutely going off about 5 hours from now. That's a very primed environment with an eroding CAP. Also if I'm not mistaken that low is deeper than modeled, already down to 994 MB in WC Kansas

[Calderon]

12 minutes ago, nwohweather said:

I could see things absolutely going off about 5 hours from now. That's a very primed environment with an eroding CAP. Also if I'm not mistaken that low is deeper than modeled, already down to 994 MB in WC Kansas

Pretty decent CU field down there and convective temp is almost achieved on the moist side of the dry line, roughly 91F. The subtle topographic enhancement from the Wichitas should be just enough. 

[mob1]

 

[Powerball]

8 minutes ago, mob1 said:

 

Decent CU field has developed along the dry line in South Oklahoma too. Could pop soon.

[Powerball]

Just now, Powerball said:

Decent CU firld has developed along the dry line in South Oklahoma too. Could pop soon.

Just as I posted that:

 

[mob1]

Confirmed tornado in NE with the tail end Charlie 

[yoda]

Never seen 5 inch hail mentioned in a watch before... TW #159 for majority of Oklahoma says just that 

[yoda]

Guess this is what happens when 21z OUN sounding has ML Lapse Rates at 9 C/KM

 

URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 159
   NWS Storm Prediction Center Norman OK
   500 PM CDT Fri Apr 29 2022

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Southwestern, central and northern Oklahoma

   * Effective this Friday afternoon from 500 PM until Midnight CDT.

   * Primary threats include...
     A few tornadoes likely with a couple intense tornadoes possible
     Scattered large hail and isolated very large hail events to 5
       inches in diameter likely
     Scattered damaging winds and isolated significant gusts to 75
       mph possible

   SUMMARY...Isolated supercells are expected to develop and move away
   from the dryline over the remainder of the afternoon.  Any sustained
   storm(s) could offer tornadoes (potentially significant/EF2+), very
   large/damaging hail, and locally severe gusts.

   The tornado watch area is approximately along and 50 statute miles
   east and west of a line from 20 miles northeast of Ponca City OK to
   35 miles south southeast of Fort Sill OK. For a complete depiction
   of the watch see the associated watch outline update (WOUS64 KWNS
   WOU9).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

   &&

   OTHER WATCH INFORMATION...CONTINUE...WW 157...WW 158...

   AVIATION...Tornadoes and a few severe thunderstorms with hail
   surface and aloft to 5 inches. Extreme turbulence and surface wind
   gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean
   storm motion vector 24030.

   ...Edwards

[nwohweather]

Guess this is what happens when 21z OUN sounding has ML Lapse Rates at 9 C/KM
 

URGENT - IMMEDIATE BROADCAST REQUESTED  Tornado Watch Number 159  NWS Storm Prediction Center Norman OK  500 PM CDT Fri Apr 29 2022  The NWS Storm Prediction Center has issued a  * Tornado Watch for portions of     Southwestern, central and northern Oklahoma  * Effective this Friday afternoon from 500 PM until Midnight CDT.  * Primary threats include...    A few tornadoes likely with a couple intense tornadoes possible    Scattered large hail and isolated very large hail events to 5      inches in diameter likely    Scattered damaging winds and isolated significant gusts to 75      mph possible  SUMMARY...Isolated supercells are expected to develop and move away  from the dryline over the remainder of the afternoon.  Any sustained  storm(s) could offer tornadoes (potentially significant/EF2+), very  large/damaging hail, and locally severe gusts.  The tornado watch area is approximately along and 50 statute miles  east and west of a line from 20 miles northeast of Ponca City OK to  35 miles south southeast of Fort Sill OK. For a complete depiction  of the watch see the associated watch outline update (WOUS64 KWNS  WOU9).  PRECAUTIONARY/PREPAREDNESS ACTIONS...  REMEMBER...A Tornado Watch means conditions are favorable for  tornadoes and severe thunderstorms in and close to the watch  area. Persons in these areas should be on the lookout for  threatening weather conditions and listen for later statements  and possible warnings.  &&  OTHER WATCH INFORMATION...CONTINUE...WW 157...WW 158...  AVIATION...Tornadoes and a few severe thunderstorms with hail  surface and aloft to 5 inches. Extreme turbulence and surface wind  gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean  storm motion vector 24030.  ...Edwards

Almost a completely unstable environment there

[MNstorms]

5 minutes ago, nwohweather said:

Almost a completely unstable environment there

Yeah just a bit unstable 

 

Well the big storm the HRRR has around Oklahoma City is forming near Binger.

[Quincy]

Initial cells are struggling to mature. What a delicate situation. So much potential for one or two intense storms, but also the likelihood that a lot of areas don’t see anything at all. 

[Chinook]

current tornado-warned storm at Minden, NE (no confirmed tornado that I know of)

[Powerball]

42 minutes ago, MNstorms said:

Yeah just a bit unstable 

 

Well the big storm the HRRR has around Oklahoma City is forming near Binger.

You can still see weak capping on that sounding, and it's really giving the storms that have tried to fire the flux.

[Quincy]

Not sure I’ve ever seen this. Most guidance backed off of dryline storms in OK/southern KS until last minute, then brought them back. Only to lose them last minute as well. WoFS is looking pretty bad right now too. Almost all cu along the dryline is dissipating. One of the harder busts of my career, but it can be a learning experience. 

[cheese007]

Funnel on Gene Theiszen's stream at severe studios

EDIT: Kory Hartman at severestudios had some interesting rotation

[Santa Clause]

Does central Kansas still have shot at tornado activity?

[MUWX]

That cell south west of Wichita looks pretty good 

[cheese007]

Rotation on Brett Adair's stream