Late May Severe Weather Threats

[Quincy]

An upper level trough, slowly moving across the Central U.S., should bring a threat of severe thunderstorms across the Southern Plains through tomorrow. The Texas Gulf Coast and parts of Arkansas/Louisiana could be affected on Wednesday, before the pattern becomes unfavorable for severe thunderstorm activity for a couple of days.

A more traditionally favored severe pattern should then setup for the weekend, through the final days of May. Ensemble guidance is in good agreement with broad troughing across the West and some ridging across the eastern half of the U.S.. While some limitations will likely prevent this stretch from being higher-end on a broad scale, isolated to scattered severe thunderstorms seem probable between about May 28-31. From a storm chasing perspective, sometimes broad troughing is preferred as you get later into spring, as storm motion can be a bit slower and mesoscale features dictate the precise placements of threats.

[Chinook]

Classic supercell west of Lubbock

[Witness Protection Program]

Still ongoing?  Tor warned currently.

Close up of the mudnado:

 

[Witness Protection Program]

Scale:

We've got a New Mexico wrapped tornado entering Texas.

[canderson]

Christ this radar 

[MUWX]

One of the more photogenic wedges we’ve seen in a while 

[Quincy]

Did not see the tornado, but was able to photograph the supercell from the south, long after the tornado dissipated. Lots of dust.

 

[nrgjeff]

Starting to believe a Northern Plains Upper Midwest sequence is on-tap beginning this weekend. Too good to be true again? Let's look under the hood.

We have reeled it well into the 6-10 day; so, I'm cautiously optimistic. Models smodels, but they are a tool. I look for failure modes, like forecasting snow in the South, haha. Any tropical depressions look buried south Gulf or Yucatan, greater than 15 degrees away from the US trough - no impact if models are right. Probably no TD anyway. Back to the hemispheric pattern forecast; well, it's amazing Rockies trough with Mid-Atlantic ridge. 

Looking at the Indian Ocean and Pacific satellite.. MJO and Kelvin Waves are supportive. Pacific jet extension is robust; look for that to poke in North America and retract, yielding the Rockies trough. Global Wind is falling, which is favorable for that pattern in late May early June. 

As for the meso-scale and daily details, see the original post by @Quincy I totally agree. This time of year I'll take broad trough with subtle waves. Boundary forecasting will also be paramount - usually the morning of. 

Barring a major debacle (which is less and less likely) we are going to tee up a sequence for the Northern Plains and Upper Midwest. Happy and SAFE chasing!

[cheese007]

Stunning video of yesterday's tornado out in Morton, TX:

 

[Chinook]

SPC upgraded the outlook today for enhanced, including Dallas, Fort Worth, Austin, and Waco.

 

[Powerball]

Not impressed with today, based on current radar/satellite trends and the chaotic moisture inflow.

Shear & forcing looks good though, so I guess that supports the enhanced risk.

[Sydney Claridge]

We’ve had some kind of outflow boundary surge across most of Tarrant County now.  I’m starting to think our severe potential just dropped.

 

That said, it would be a different story if that boundary can come back northwest after this first round of (non-severe) storms.  The boundary is surging southeast right now, so I don’t really foresee it moving back northwest, but I'll be sure to keep an eye on temperatures and dewpoints to see if they start increasing.

[Chinook]

possible severe watch coming for mid-Texas

Quote

 Mesoscale Discussion 0900
   NWS Storm Prediction Center Norman OK
   0142 PM CDT Tue May 24 2022

   Areas affected...portions of west-central into northern Texas

   Concerning...Severe potential...Watch likely 

   Valid 241842Z - 242015Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Convection is expected to develop and rapidly increase in
   coverage and intensity across parts of west-central Texas into
   northern Texas this afternoon. Large hail and damaging gusts will be
   the main hazards with this activity.

   DISCUSSION...A somewhat messy convective scenario is expected to
   unfold over the next couple of hours across portions of west-central
   Texas near the surface triple point into north Texas along the
   surface outflow boundary. Initial convective development is expected
   soon east of Midland to near San Angelo ahead of the surface dryline
   and near the roughly west to east oriented surface boundary.

 

[Chinook]

The town name of "Wall" might describe the situation. Areas around San Angelo got hail, baseball to softball size.

[weatherextreme]

TXC049-083-242230-
/O.CON.KSJT.TO.W.0003.000000T0000Z-220524T2230Z/
Brown TX-Coleman TX-
515 PM CDT Tue May 24 2022

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR
SOUTHWESTERN BROWN AND SOUTHEASTERN COLEMAN COUNTIES...

At 514 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Trickham, moving east at 25 mph.

HAZARD...Tornado and two inch hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows, and vehicles will occur.  Tree damage is
         likely.

This dangerous storm will be near...
  Trickham around 520 PM CDT.

[Radtechwxman]

Are they going to survey the Morton, TX tornado or did it even hit anything?

[stormdragonwx]

9 hours ago, StormChaser4Life said:

Are they going to survey the Morton, TX tornado or did it even hit anything?

Been curious about that too. Been wanting to know what it's width and intensity was. It is safe to say if it did form over and/or hit an urban area it would have caused devastating damage, especially with it's slow forward motion.

[Radtechwxman]

9 hours ago, stormdragonwx said:

Been curious about that too. Been wanting to know what it's width and intensity was. It is safe to say if it did form over and/or hit an urban area it would have caused devastating damage, especially with it's slow forward motion.

Was that in Lubbock's jurisdiction? I keep checking their Twitter and haven't seen anything. 

[MNstorms]

I guess this season is going to be the one that keeps on giving in the Dakotas and Minnesota. 

[Quincy]

Looks like Sunday-Monday have noteworthy severe potential, somewhere between the Central Plains and Upper Midwest. We could see the threat linger into Tuesday, before troughing ejects toward the Ohio Valley. Just in time to close out May.

[MNstorms]

Sunday

 Scattered severe thunderstorms are likely over Nebraska
   northeastward into Minnesota on Sunday and Sunday night. 
   Significant severe weather including very large hail and
   hurricane-force gusts are possible with the strongest storms. 
   Several tornadoes are also possible.

   ...Synopsis...
   The exit region of a powerful, cyclonically curved upper jet is
   forecast to overspread the central High Plains into the mid MO
   Valley during the period as a large-scale mid-level trough
   encompasses the West.  A mid-level anticyclone will reside over the
   Carolinas.  In the low levels, a surface front perhaps augmented by
   convection is forecast to extend from the Upper Midwest
   southwestward to a triple point near the northwest KS/NE border.  A
   dryline will extend southward into the southern Great Plains.

   ...Central Great Plains into the Upper Midwest...
   A strong to severe thunderstorm cluster may be ongoing early Sunday
   morning over parts of the eastern Dakotas where strong 850 mb
   theta-e advection is forecast.  Isolated hail/wind would be the
   primary threats with this elevated activity.  Farther south, strong
   southerly flow will aid in moisture transport northward into the mid
   MO Valley and Upper Midwest.  Strong heating, contributing to
   evapotranspiration beneath a stout capping inversion associated with
   an elevated mixed layer, will yield a very unstable airmass
   (3000-4500 J/kg MLCAPE) over parts of NE northeastward into adjacent
   SD/IA/MN.  Forecast soundings show some low-level veering and
   strengthening of winds with height, strongly supporting supercells
   with initial storm development during the late afternoon/early
   evening.  Large to very large hail is likely with the more intense
   supercells.  Tornadoes are also possible, especially in warm-sector
   areas early on where temperature-dewpoint depressions are not too
   large (less than 20 deg F).  An evolution towards clusters is
   expected during the evening as a central Great Plains LLJ
   intensifies.  A lingering threat for hail/wind will probably
   continue through the evening into the overnight.

[nrgjeff]

Sunday and Monday are clear eastern ND and western Minn. Checks air fare to MSP. Details 3rd paragraph.

First Saturday, I would target just behind the boundary intersection near the Black Hills. Roads are not ideal, but terrain can help even if the SPC fades the set-up. Black Hills are behind the cap (good) - and boundaries (meh) so, it is a pure terrain play.

Sun/Mon both feature double short waves and double surface responses. Yes 3-4 days out, but models are not going to blow that basic type of forecast. Trouble is northern waves drag up warm 850 Ts ahead of southern waves. Gosh, like forecasting snow busts in the South!

OK back to the Plains. Nebraska gets boundary intersections. Excellent CAPE is under worst cap. Easier cap is right on or behind boundaries. You know, I don't like right on boundary initiation any better than just-in-time moisture.

Eastern North Dakota and Minnesota enjoy a better set-up IMHO Sun/Mon. Frontal waves and perhaps warm front intersection with more traditional boundaries. Less cap. Still good CAPE. Said boundaries promote local SRH. Someone on another forum mentions June 17, 2010 but who knows. Saw after making my thoughts. 

Tuesday (or as early as Monday Neb.) could still go Nebraska Kansas, but LLJ moves out as main trough ejects. That's faster for Tuesday, and takes away a solid chase day.

Bottom line: Sunday and Monday look like the kind of days that can work out eastern ND western Minn. Saturday junk will deposit other boundaries for Sunday. Rinse and repeat Mon. Maybe Tue.

[MNstorms]

NAM likes Monday a lot more than Sunday. No cap on Monday.

[Quincy]

Chased western South Dakota today. Convergence on the north side of the Black Hills helped a high based supercell form, but storms very quickly became outflow dominant and clustered. 

Had a neat sunset, at least. Convective initiation may be more widespread tomorrow with stronger forcing and somewhat better moisture. Still, most CAMs snow linear segments and bowing structures, despite seemingly (supercell) favorable wind profiles. It seems like another day to hang around the Black Hills, OR head south and hope for something to stay somewhat more discrete and tap into better moisture down in Nebraska. 

[MNstorms]

16 hours ago, nrgjeff said:

Eastern North Dakota and Minnesota enjoy a better set-up IMHO Sun/Mon. Frontal waves and perhaps warm front intersection with more traditional boundaries. Less cap. Still good CAPE. Said boundaries promote local SRH. Someone on another forum mentions June 17, 2010 but who knows. Saw after making my thoughts. 

As someone from Minnesota I don't think I've seen this strong of wording here before and it's Day 3. Even June 17, 2010 Day 1 wording looks lighter. At least a moderate risk for Day 2? Also what is the difference between large and giant hail? 

...SUMMARY...
   Scattered severe thunderstorms are forecast from parts of the Upper
   Midwest southward into the central Great Plains on Monday and Monday
   night.  Tornadoes, perhaps a few strong tornadoes, large to giant
   hail, and severe gusts are possible.

   ...Upper Midwest into the central Great Plains...
   A potent mid-level shortwave trough will move through the base of a
   larger-scale trough --centered over the Great Basin-- from southeast
   CO northeastward to northern MN while evolving into a mid-level low
   by daybreak Tuesday.  An associated 500 mb speed max will intensify
   during the day with 100 kt southwesterly flow progged over eastern
   Nebraska by the late afternoon.  A cyclone will deepen as it moves
   from northern KS north-northeastward into eastern SD by mid evening
   before occluding.  A dryline will extend south-southwestward from
   the lower to mid MO Valley into central KS and near the TX
   Panhandle/OK border.  

   Isolated elevated thunderstorms are possible early Monday morning
   from remnant storms on the nose of a strong LLJ in the SD/NE/IA/MN
   region.  This activity will likely dissipate during the morning as
   strong southerly flow advects richer low-level moisture northward
   into the Upper Midwest by midday.  Model guidance indicates mid to
   upper 60s dewpoints from the Upper Midwest southward into IA. 
   Large-scale ascent associated with the approaching disturbance will
   likely lead to scattered storms initiating by the early to mid
   afternoon northeast of the northeastward-developing cyclone. 
   Enlarged hodographs and strong shear through a deep layer will favor
   supercells, especially in the eastern Dakotas/western MN area during
   the afternoon.  Tornadoes and large hail are possible with the more
   intense supercells.  A few of the tornadoes may be strong given 300+
   m2/s2 0-1 km SRH.  Additional storms are forecast to develop by the
   early evening across southern MN into IA with severe gusts becoming
   increasingly probable, in additional to a lingering hail and perhaps
   tornado risk.

   Farther south along the dryline, a capping inversion will weaken by
   the mid-late afternoon amidst a very unstable airmass (3000-4000
   J/kg MLCAPE).  Once the cap is breached, rapid supercell development
   is expected on the southern flank of a cluster of storms from
   southeastern NE into central KS.  Large to giant hail is possible
   initially, and as the low-level flow increases during the 23-01z
   period, the risk for a tornado will correspondingly increase along
   with the risk for a strong tornado.  Storms will probably
   consolidate during the evening as 850 mb flow increases and the risk
   for a tornado will gradually lessen by mid-late evening as the main
   threats transition to primarily a wind/hail threat into the
   overnight.

[Quincy]

4 hours ago, MNstorms said:

Also what is the difference between large and giant hail? 

Large hail = 1” or larger in diameter

Very large hail = 2” or larger

Giant hail = 4” or larger

[nrgjeff]

Monday I agree that Minnesota is the primary target (MN Storms). Chasers with the time and energy should get up there.

We will probably target the south end in Neb. Kan. Note a frontal occlusion is forecast between targets Monday; so, it's one or the other.

South target the DL and CF separate again. Also the front from the North low may drape in such a way to act like a stationary front east of the South TP. Sunday night rain may also deposit outflow boundaries for Monday. Finally Monday LLJ will be strong South too; so, it should anchor such east-west boundaries. Good for Monday Madness.

Again the day could be more historic up in Minn. We have to play south target in case the chase goes into Tuesday.

[Quincy]

@MNstormsready to add to the wealth?

 

[Torchageddon]

14 hours ago, MNstorms said:

 

 

...SUMMARY...

   Isolated elevated thunderstorms are possible early Monday morning
   from remnant storms on the nose of a strong LLJ in the SD/NE/IA/MN
   region.  This activity will likely dissipate during the morning as
   strong southerly flow advects richer low-level moisture northward
   into the Upper Midwest by midday.
  

What will facilitate the dissipating of those storms in the morning?

[Quincy]

An interesting setup tomorrow with several nuances that make for a difficult forecast. I doubt we will have high confidence on details until at least mid to late morning. The synoptic setup shares some DISTANT similarities to the 6/16 - 6/17/2014 sequence. I am not calling for the same evolution, but I do recall the Pilger day and similar surface features. The difference here is that we're a few weeks earlier in the season and the moisture field may be somewhat fragmented, resulting in more capping and delayed initiation. Interestingly enough, 6/17/2014 was a late initiation day in the same general area (northeastern Nebraska), with storms not firing until only a couple of hours before sunset.

Anyway, I attempted to roughly illustrate the current mean HREF surface map features, effective 21z/4 PM Sunday. The area to watch is likely the triple point, somewhere in central/south-central Nebraska. I wouldn't say it's a true front, but it appears as if a surface trough will drape south from an area of low pressure over eastern North Dakota, toward a low near the Kansas/Nebraska border. A dryline will probably intersect the low at an effective triple point. Low-level moisture fields appear to be fragmented, as a moisture gradient may exist, displaced slightly to the east, over Iowa. There, strong capping will likely preclude convective initiation prior to loss of daytime heating. Storms could fire along the trough (both across eastern Nebraska and farther west toward the High Plains), but it seems as if the best shot an initiation, perhaps only 1-3 hours prior to sunset, would be near the triple point.

We could see early day storms also bring a hail risk to the Upper Midwest and might there be some warm front action across Minnesota/Wisconsin as well? Maybe even attempts at convective initiation along the trough over the eastern Dakotas?

Definitely an odd, complex setup. Some models struggle to convect prior to 00z. If initiation is too soon, there may not be adequate boundary layer moisture recovery across Nebraska. The sweet spot seems to be somewhere over the eastern half of Nebraska, around 6-9 PM, assuming that the cap is breached and storms can form near/ahead of the triple point. If storms were to fire on the northwest side of the trough/low, they will be displaced from better moisture/wind fields in the lower levels.