WeatherArc

SPC keeps D1 moderate, likely waiting for first weather balloon data to come in from launches this morning before making the decision to go high. Cant get anymore high-end wording than this though, ..THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PARTS OF WESTERN/CENTRAL/NORTHEAST OKLAHOMA INTO SOUTH-CENTRAL AND SOUTHEAST KANSAS... ...SUMMARY... Numerous severe thunderstorms are expected to develop and move eastward Monday afternoon through Monday night across parts of the southern/central Plains. Multiple intense, long-track tornadoes, very large to giant hail, and severe/damaging winds all appear likely . ...Synopsis... A potent shortwave trough is evident in water vapor imagery this evening within the Great Basin. This feature will continue eastward into the Four Corners by early this morning. An initial speed max is expected to eject into western Kansas. By late afternoon into the evening, another speed max will approach western Oklahoma. Deep low-level moisture is already being observed in the BRO 00Z sounding. Surface observations also show low 70s dewpoint as far north as the DFW Metroplex this evening. As the trough approaches, this moisture should stream northward. The overall synoptic setup indicates a severe weather outbreak occurring this afternoon and extending into the evening and parts of the overnight period. Multiple intense, long-track tornadoes are expected, especially in parts of southern Kansas into Oklahoma. Very-large hail of up 2-4 inches can also be expected with intense supercells. Severe gusts may initially be isolated, but storm coverage should increase with time as well as the mode becoming more linear. As this occurs, severe gusts, some up to 80 mph, will become more common. ...Oklahoma into southern Kansas... Intense storms are expected across these areas by late afternoon. Storm coverage is likely to initially be greatest in south-central Kansas given the greater and earlier upper-level forcing. Isolated storms will still be possible along the dryline in western Oklahoma as strong heating in the Texas Panhandle should support dryline circulations that should at least locally erode inhibition. By the evening, greater forcing for ascent will arrive in western Oklahoma. Flow aloft will be nearly perpendicular to the dryline, which will favor a discrete storm mode. Even as the weak Pacific front overtakes the dryline, low-level forcing is not expected to be strong enough to promote substantial upscale growth, especially when coupled with continued strong shear across the boundary. Overall, there appears to be prolonged opportunity for discrete storms to form across western Oklahoma into parts of southern Kansas. While the environment during the afternoon will certainly support intense, long-track tornadoes, concern only grows by early evening. Discrete storms are expected to move eastward into an intensifying low-level jet core in central and eastern Oklahoma into southeast Kansas. Surface-based activity will likely persist into the evening and even parts of the overnight, given continued influx of moisture and weak capping. The time frame of greatest concern for intense tornadoes is from 03-06Z across central into northeast Oklahoma. This is a high-end environment. An upgrade to a tornado-driven High Risk was considered. There remains some lingering uncertainty with regard to the number of intense tornadoes that will occur. An increase in tornado probabilities will certainly be warranted should confidence in coverage and preferred corridors increase. ...Western Kansas into Nebraska...Iowa...Missouri... Convection will likely initiate in western Kansas into southwest Nebraska earlier than elsewhere given the timing of the upper-level forcing. Furthermore, a linear mode should more quickly become established due to the deep layer shear being oriented much more parallel to the initiating boundary than farther south. Buoyancy will generally decrease with northward extent. That being said, moisture will continue to push northward through the day and into the evening. Mid 60s F dewpoints could reach southeast Nebraska. Strong deep-layer and low-level shear will promote an organized line of convection capable of wind damage and QLCS tornadoes (some potentially strong). There is some potential for discrete storms to form ahead of the anticipated line. These storms would pose a greater threat for significant tornadoes. Large to very large hail will likely be more likely in western and central Kansas and coverage of very large hail will be conditional on how long a discrete mode is maintained . ...South Dakota... Richer low-level moisture (upper 50s to perhaps near 60 F dewpoints) will reach portions of central into northwest South Dakota. A narrow zone of instability is expected to develop by the afternoon between the cold and warm front. Large hail and severe gusts will be the main threats, but low-level shear will be sufficient for a tornado or two. ...Edwards Plateau into Texas Rolling Plains... Storm coverage this far south should generally be much more isolated on account of weak and nebulous forcing. However, a strong enough dryline circulation could initiate convection within a strongly unstable and sheared environment. Should storms form, large hail and severe wind gusts would be possible. 06z HRRR has multiple discrete supercells in a very high end environment. Oklahoma and southern Kansas need to be on the highest alert today

Decided to stay up for 00z HRRR, wow. Too put it bluntly if this run verifies a significant outbreak of strong-violent long track tornadoes would occur. Multiple discrete supercells firing off the dryline at 00z in northern Oklahoma and southern Kansas, tracking well into the night while remaining relatively discrete, additional development at around 9pm local time in central Oklahoma. I also think central/southern Oklahoma should be on high alert for this, considering the level of forcing inbound at 300mb, the sharp dryline and the HRRRs biases despite what the 00z shows i am fairly confident in dryline convection from Fairview to Lawton in central Oklahoma. Soundings picked from all over the warm sector in southern Kansas and Oklahoma. Timing of soundings varies between 00z and 03z. Am going to try to sleep for as long as i can now, likely not to get much tomorrow night. Its also worth noting the csu is showing very high probs for Wednesday night as well.

Yup, glad im not the only one who clocked it. Im not saying this is going to be on the same level but i am saying that the hodographs we have tomorrow can produce significant tornadoes. Storm mode/coverage could mitigate the ceiling of this event but very important for anyone in Oklahoma and Kansas to prepare for severe weather. 18z models may well downgrade the risk, but the number of potential bust scenarios are fading. We do need to watch for what the cap does after 00z

That hodograph from Kyles post reminds me a lot of a certain outbreak in the plains, we'll see what happens in the next 24 hours but its a potent look. 12z NSSL

Sparkiee storm Im not sure they will tonight but if the models are still looking the same tomorrow, this setup will defo warrant an upgrade imo.

12z HRRR is concerning It fires storms in central Oklahoma at 03z or 9pm local time, despite the late timing these cells will have an incredibly juicy atmosphere, 4,000 mlcape with over 150 3cape in many areas. If these cells can fight off nocturnal capping and the boundary layer remains coupled, this is a very significant environment.

Few things that stands out to me, the nam really doesnt decouple the boundary layer meaning these storms are still fully rooted to the surface at 03z, also means nocturnal cooling is very slow so less cinh/cap developing as the surface cools, Mesolow develops in north-western Oklahoma, evident on most models. This acts as a shear enhancer across central OK, also helps to keep pulling moisture straight up into these supercells, again helping to stop decoupling. Confluence bands very evident in Kansas, these can very well act as small atmospheric triggers for storms to fire off, discrete development from these confluence bands is still uncertain but increasingly probable. Whether these confluence bands make it down to Oklahoma is still very uncertain. Discrete development very likely in Oklahoma, shear vectors are pretty perpendicular to the initiating dryline boundary in OK, favouring discrete supercells.

*Stormforce~beka* With Reed and his friends its better not to know

We now have a day 2 moderate in place for Central Oklahoma and southern Kansas, strong long-tracked tornadoes, large-giant hail and damaging thunderstorm wind gusts of over 70 mph are now looking increasingly probable. SPC summary below, ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WESTERN/CENTRAL OKLAHOMA AND SOUTH-CENTRAL KANSAS... . ..SUMMARY... Numerous severe thunderstorms are expected to develop and move eastward Monday afternoon through Monday night across parts of the southern/central Plains. Multiple strong/potentially long-track tornadoes, very large to giant hail, and severe/damaging winds all appear likely. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low will consolidate over the northern High Plains of eastern MT into western ND/SD and vicinity, with a secondary surface low forecast to develop over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline and southeastward-moving cold front. A warm front should eventually reach eastward across parts of NE/IA. This warm front should be the northern limit of appreciable severe-thunderstorm potential through Monday night. ...Southern/Central Plains... Confidence has increased in a corridor of greater potential for strong tornadoes and very large hail, with multiple supercells likely to develop across south-central KS and western/central OK late Monday afternoon and continuing through much of the evening. Accordingly, a Moderate Risk has been introduced for this area. Daytime heating of the moist low-level airmass, coupled with steep mid-level lapse rates, will foster moderate to strong instability developing along/east of the dryline Monday afternoon. Peak pre-convective MLCAPE will likely reach 2500-4000 J/kg across much of central KS into western/central OK and northwest TX. Strong deep-layer shear of 40-50 kt will easily support supercells with initial thunderstorm development. Convective initiation appears likely by early Monday afternoon as ascent with the lead shortwave trough overspreads NE/KS. Very large hail will be a threat initially, but most guidance suggests a fairly quick transition to a more linear mode with time Monday afternoon/evening, especially as the cold front overtakes the dryline. An increasing threat for damaging winds and embedded tornadic circulations will likely occur as this mode transition occurs, in tandem with strengthening boundary-layer shear associated with a strengthening southerly low-level jet. This damaging-wind/tornado threat may continue into the overnight hours into parts of IA/MO, and the Slight Risk has been expanded eastward to account for this potential. Farther south across western OK and south-central KS, more modest large-scale ascent and related mid-level height falls associated with a more westerly mid/upper-level jet will eventually overspread the dryline and warm sector by late Monday afternoon. Although overall convective coverage will likely be lower compared to locations farther north, there should be a better chance for supercell structures to be maintained, as deep-layer shear vectors appear more orthogonal to the initiating boundary (dryline). A southerly low-level jet should strengthen to around 40-45 kt through early Monday evening across this area, greatly enhancing corresponding low-level shear and effective SRH. The best chance for strong, potentially long-track tornadoes and giant hail (3-4 inches) should exist with any supercells that can persist Monday evening in a very favorable thermodynamic and kinematic parameter space. Similar to locations farther north in KS/NE, upscale growth should eventually occur across central/eastern OK. A threat for damaging winds and tornadoes (some potentially strong) should continue Monday night into early Tuesday with eastward extent across the southern Plains given a sufficiently unstable and strongly sheared environment. The latest two nam runs are concerning, it keeps a pristine thermodynamic environment throughout the evening and well into the night 00z Sounding 03z soundings We shall see where model trends take us over the next 24 hours but a significant severe weather event looks possible

Reeds vid from inside that powerful rain wrapped wedge yesterday, was watching the livestream when it happened, probably the most nervous ive ever been watching a reed stream, especially when he started to say we're in a bad spot here, glad he made it out ok i know he knows what hes doing but way too close for comfort for me Especially with how deviant the tor was. Almost directly under the velocity couplet!

Now thats a very interesting ensemble run for monday

Allseasons-Si Another day, another beautiful tornado 2024 on a roll

Next week csu probs are very high, especially on Mon and Weds where an equivalent to a high risk is in place. Monday is still up in the air, i know a few have said it doesnt look great due to faster trough but to be honest until we get to the day of i wouldnt start calling it a bust. Especially due to the nam 3km, very potent environment with discrete supercells in south eastern Oklahoma, look at the environment they have to work with!

Before things potentially start ramping up again, heres a look at the 18z Nam for Monday, starting to look like a big day for severe weather. Pretty high end wording per spc ...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/MON.. . ...DISCUSSION... A multi-day period of organized severe thunderstorm potential appears likely across parts of the central to eastern CONUS next week, beginning on Day 4/Monday across the Plains, and continuing through at least Day 6/Wednesday. ...Day 4/Monday... A negatively tilted upper trough will eject northeastward over the northern/central Plains on Monday. Pronounced low-level mass response will encourage rich low-level moisture to advect northward over the southern/central Plains, as a surface low rapidly deepens over the northern High Plains. Strong deep-layer shear and at least moderate instability are expected to be in place ahead of a surface dryline extending across the southern/central Plains. Thunderstorms will likely erupt along the length of the dryline by late Monday afternoon from southern NE into central KS and north-central OK. Supercells are likely to be the dominant mode initially given the strength of the deep-layer shear. Both very large hail and tornadoes will be possible with these supercells as they spread eastward across the southern/central Plains through Monday evening. With a southerly low-level jet forecast to strengthen to at least 50-60 kt Saturday evening, a corresponding rapid increase in low-level shear will likely support a continued threat for tornadoes with any discrete convection. Some of these tornadoes could be strong. The severe threat will likely continue Monday night with eastward extent across the Plains, before convection possibly weakens some towards early Tuesday morning. Given increased confidence in high-end severe potential, a 30% severe area has been introduced from parts of southern NE into central KS and north-central OK.

Both these cells need watching, southern cell is going through merger with shower while northern one has a lowering on vinces stream

Our tornado producing storm to the north is about to start interacting with a newly formed cell to the south, looks like the next area to watch. Also note the Outflow boundary just to the west of San Angelo.

I know reed knows what hes doing but that was very close, he was practically in the outer edges of the tor.

Very violent tornado

What is reed doing

Some sort of eye forming on reflectivity where the tor is, just like the tor in Oklahoma a few days ago

The tornadofest that is 2024 continues

On this day 25 years ago the most violent tornado ever recorded would touch down close to Amber, Oklahoma and track along a 38 mile track for an hour and 25 mins, directly impacting the towns of Bridge Creek and Newcastle as well as the populated suburb of Moore, south of Oklahoma city, this tornado would produce some of the most extreme damage ever recorded, a national weather service doppler on wheels would record a maximum wind gust of 318 mph, becoming the strongest wind gust ever to be recorded on earth. Sadly this tornado would be responsible for 36 deaths, 583 injuries and 1.8 billion dollars of damage. A total of 8,132 homes, 1,041 apartments, 260 businesses, eleven public buildings, and seven churches were damaged or destroyed. This was also the first time a tornado emergency was ever issued "SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE NORMAN OK 657 PM CDT MON MAY 3 1999 ...TORNADO EMERGENCY IN SOUTH OKLAHOMA CITY METRO AREA... AT 657 PM CDT...A LARGE TORNADO WAS MOVING ALONG INTERSTATE 44 WEST OF NEWCASTLE. ON ITS PRESENT PATH...THIS LARGE DAMAGING TORNADO WILL ENTER SOUTHWEST SECTIONS OF THE OKLAHOMA CITY METRO AREA BETWEEN 715 PM AND 730 PM. PERSONS IN MOORE AND SOUTH OKLAHOMA CITY SHOULD TAKE IMMEDIATE TORNADO PRECAUTIONS THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. IF YOU ARE IN THE PATH OF THIS LARGE AND DESTRUCTIVE TORNADO...TAKE COVER IMMEDIATELY. DOPPLER RADAR INDICATED THIS STORM MAY CONTAIN DESTRUCTIVE HAIL TO THE SIZE OF BASEBALLS...OR LARGER." Some of the damage The tornado was part of a wider outbreak with many other powerful tornadoes, imo this is likely one of if not the most high end plain outbreaks ever recorded. Heres some good videos either from or about the event. (This one below is really good, follows the tornado in real time, second by second) (32 mins onwards is just insane) (This was Reeds 6th ever tornado)