WeatherArc

Omaha, Nebraska needs to watch this very closely, given increasing low level shear.

Reed going for an intercept

Insane

HOLY SH*T

Tornado down in Lincoln! https://www.youtube.com/watch?v=fF1W_mwJu2M

Im not liking the path of the Lincoln storm, major metropolitan areas directly to its north east.

Reports of homes levelled near Emmet Texas on Ryan's stream Lincoln cell reportedly has rapid rotation https://www.youtube.com/watch?v=fF1W_mwJu2M

Believe this is the Lincoln cell https://www.youtube.com/watch?v=fF1W_mwJu2M

The Lincoln cell was on Ryans stream a few mins ago, looking increasingly like its going to drop something. Honestly imo the spc should upgrade to moderate at 20z, large overperformance and not even main event yet.

Awesome drill bit in Nebraska with very fast forward motion, seems every storms producing tornadoes.

Developing supercell on Ryans stream

I've missed chase days like this so much, dryline days are just the best, temps in the upper 20s low 30s, beautiful cumulus towers with a deep blue sky and some absolutely amazing chase terrain, no other place in the world like the plains.

Reed live for todays conditional threat of strong tornadoes and large hail Some tornado warned storms already around. Development underway in the Texas/Oklahoma panhandles as well as Western Kansas.

RRFS also now in range, has some morning convection, in my experience rrfs slightly overdoes am convection and clouds, but even with it doesn't particularly do much to the environment west of I35, Multiple Kansas supercells and a very classic I44 supercell in OK. The Wichita mountains in south western Oklahoma can often act as a small scale forcing mechanism. Its unfortunately why Moore is so infamous for tornadoes, storms develop over the mountains and track to the northeast into OKC metro. Oklahoma and Kansas need to watch this day very closely.

The first cams now in range for sat, what a look from the 3km NAM, interestingly its the only model that adds a slight inversion, could well be a model bias but interesting to see. Just look at the warm sector, 3-4000 j/kg cape, curved and inflated hodographs just absolutely high end. Some weirdness going on with hodographs at 2-3km, this is 100% a nam bias where it underdoes your 700mb winds. Friday is also worth looking at, especially with the recent HRRR HRRR gets into range of sat at 2am tonight, may be worth staying up for. Defo 2 days of moderate potential, maybe even high for sat but just depends on either the morning convection firing then shooting out of the target area with little cloud cover or just not going up at all.

18z NAM pretty much the same as the 12z just an absolutely classic look for a significant tornado outbreak across Kansas and Oklahoma. Soundings from Oklahoma Soundings from Kansas Only one major fail mode is really possible with this kind of setup, that being morning convection. Lets see what our cams show over the next 3 days. Here's the area forecast discussion from the national weather services local office in Wichita, Kansas "Saturday has the potential to bring significant severe weather to the area. Of course there is plenty of time for the forecast to change and there does remain some degree of uncertainty particularly in storm mode. A sfc low in the vicinity of SW KS is progged to deepen and move east/northeast potentially around central/south central KS by peak heating. Moderate to strong instability (2500-4000 J/kg) will combine with strong flow (60kts+ bulks shear), nicely curved hodographs/strong LL SRH, and strong 3CAPE (200j/kg). Any storm that can remain discrete or even semi-discrete in this type of environment will pose significant hazards from strong to potentially violent tornadoes, large to very large (2-3+ inch) hail, and damaging wind gusts." Wonder if a day 3 moderate will be issued, maybe not cause of morning convection but still a possibility.

NCAR updraft helicity for sat, Kansas and Oklahoma stands out with Kansas having a less discrete mode. Oklahoma has 2 prominent discrete storm tracks. As posted by @Eagle Eye the 12z NAM has a very, very potent environment, we'll see if the trend sticks but sat could genuinely be the highest end threat the plains has had for many years. Soundings from Oklahoma Soundings from Kansas

Dont get me wrong Saturday still has fail modes, especially regarding morning convection but this 500mb chart could seriously be in a meteorology textbook page for what a significant tornado outbreak trough in the plains looks like. Strong belt of flow rounding the base and ejecting into the area at peak heating, negative tilt, divergence aloft. Recent trends have slightly slowed the trough ejection and further amplified the jetstreak. This is important, a faster ejection=less time between morning convection and our main event. Comparing past significant tornado events with this type of trough ejection the one that sticks out to me as looking the most similar is May 24th 2011, will we reach that ceiling? Im not convinced at the moment but the potential is there. Nam comes into range in about 2 hours interesting to see what it shows. Two other failure modes i can think of are lingering cloud cover and storms firing too early to make use of LLJ, also not 100% with lapse rates but lets see what CAMS do. CSU very potent though Ben Sainsbury I still think late may and early june has very good potential, big cape storms that only require a gust of wind to surge the RFD and drop a photogenic cone. Good luck out there!

Im not surprised by the spcs upgrade for thursday although it is very rare for them to upgrade the day 3 risk. A lot of shorter range models have the dryline firing. Any discrete supercell that can sustain itself will be capable of golfball-baseball sized hail, 70+ mph straight line wind gusts and strong-violent tornadoes. I also think the spcs decision to upgrade was partly due to the csu machine learning showing the equivalent of a high risk for the area, never seen that before! 21z RAP very potent, two dryline bulges one in Texas panhandle and another in Northern Kansas. Soundings from Texas panhandle Soundings from Northern Kansas Wonder if we see a 30% upgrade for fri and sat tomorrow morning, looking at models at the min both days certainly meet the threshold.

If we dont see downtrends in the next few days saturday is going to be a problem, a significant trough ejection with strong flow rounding the base, negative tilt and ejection right at peak heating. At the minute everything synoptically speaking looks very favourable for a high end severe weather outbreak. A sub 997mb low is expected to develop with a strong (50-60 knot) low level jet. The existence of subtle confluence bands was also pointed out on twitter. In regimes with less forcing these bands can help give just enough lift for storms to fire off allowing for discrete convection. I do think its important to urge some caution though, differences do still exist in models. Look at the ukmets depiction, much less favourable with trough way behind. Weve had the wheels fall off the train before (especially our last setup) so lets see what the NAM and other short range models show when they get into range tomorrow/Thursday. Overall though, thursday, Friday and Saturday all are looking like good chase days with severe weather with all hazards possible. RRFS for thursday Nam 3km also for thurs NAM for friday SPC now upgraded Thursdays risk to a day 3 enhanced. "Severe thunderstorms are likely from late Thursday afternoon into Thursday night across parts of the central and southern Great Plains. Very large hail, severe wind gusts, and strong tornadoes will all be possible. Guidance continues to suggest strong buoyancy will be in place ahead of a negatively tilted shortwave trough ejecting across the southern High Plains. General forecast expressed in the previous outlook remains valid, but confidence in an area of greater severe-weather potential has become more apparent with the most recent guidance. Late afternoon development is anticipated across the TX Panhandle, with these storms quickly becoming severe and capable of large to very large hail up to 3" in diameter. Low-level moisture may be later to arrive in west-central/southwest KS, delaying convective initiation to a few hours later than farther south. Large to very large hail is anticipated with initial development across west-central/southwest KS as well. In both of these areas, storms are expected to move east-northeastward off the dryline, encountering strengthening low-level southerly flow and environment that is increasingly favorable for tornadoes. Low-level shear will continue to strengthening into the early evening, and the overall environment supports the potential for strong to intense tornadoes if a discrete mode can be maintained." Interestingly, CSU now predicting a very small area equivalent to a high risk for Thurs, i think it will be very conditional due to cap but a significant severe event is possible if storms can fire.

The upcoming period from April 25th to May 5th is likely to be the most active stretch we've had this year and possibly the most active the great plains has been since 2019. Starting with thurs night, a 'primer' negatively tilted shortwave will eject across the region, this trough will both bring the risk of supercells with all hazards and prime the atmosphere by doing the job of pulling up moisture for following troughs to use. A 993mb surface low will develop with an associated 35-42 knot low level jet. Despite being a primer ejection moisture should be plentiful with dewpoints in the mid 60s and a sharp dryline. Steep lapse rates should also aid instability. Cape should be in the range of 1,500-2,400 j/kg sufficient for severe thunderstorm development. Looking at hodographs i wonder if cells will start as hailers before transitioning to tornado producers as hodographs become more curved. As the shortwave ejects into friday night it will deepen further with a vortmax over South Dakota. The associated low level jet will continue to strengthen as surface low pressure drops to around 987mb. Due to the large warm sector and strong low level jet severe storms are possible from Iowa to Texas. On sat night the second trough arrives and ejects over the same areas as thursday nights risk. A trough that looks like that at 500mb ejecting at peak heating means trouble. 12z GFS gives me big May 24th 2011 vibes. Classic Colorado surface low develops and tracks along panhandle, pressure down to 989mb with low level jet in the 50-60 knot range. Relatively steep lapse rates and dewpoints in the upper 60s and low 70s should result in cape values of 2400-3000 j/kg. Curved/Inflated hodographs should foster a significant severe threat with any discrete supercell, with all hazards. However, some failure modes do exist. Firstly with the weak upper level shear, while low level shear should be more than sufficient. Mid-especially upper level is iffy could lead to more HP cells or supercells struggling, also would like to see bulk shear vectors more perpendicular to initiating boundary, the more parallel they are the less discrete the storm mode. Cloud cover may also be an issue but i never trust models on that and always look at satellite the day of. The main failure mode though is the trough being mistimed or not happening at all, the GFS has trended much faster with its timing with the trough moving in with peak surface heating unlike yesterday where it had it coming through at night, things could still trend back though. The 00z GDPS is the weirdest solution ive seen though with no large trough ejection and a more zonal flow, not sure i trust this model but its worth keeping an eye on. While the pattern looks favourable i think its incredibly important to stress how many times weve seen these events fall apart as we get into the 84 hour range. Overall though, a multi-day severe weather event is likely for portions of the plains and midwest as an active wave train pattern brings multiple trough ejections combined with good moisture. Looks like a very active stretch for storm chasing! Talking about May 24th 2011 im reminded of this good pecos hank vid. The footage 57 seconds in is some of the scariest tornado video ive seen. Apart from El Reno 2013 and Moore 1999 this is one of the strongest tornadoes ever to be captured on film, i believe peak winds in this thing were estimated to be 295+mph. Notice the rolling horizontal vortex on the left side of the tornado at 1 minute! Reed also made a twitter live covering this active stretch

Big time uptick in severe weather likely going into next week with a day 6 and 7 15% issued with another 15% likely to be issued for Saturday as well. Heres what our GEFS is showing, decent support for an initial shortwave on the 25th followed by a larger trough ejection around the 27th. Past few runs of the GFS have also shown this ejection, good moisture and instability in place The Euro/EPS seems to agree with the GFS, slightly different in how it ejects the trough in regard to timing but thats to be expected at this range. Tilt of trough, and surface features such as the surface low positioning and mass response all still unclear at this range.