On the evening/night of May 7th, a squall line moved from NW Missouri into central MO, leading to a couple of wind reports.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS EAX wrote it up.
On the evening/night of May 7th, a squall line moved from NW Missouri into central MO, leading to a couple of wind reports.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Kansas City, MO wrote its last area forecast discussion before the first event at May 7, 5:59 PM CST, 2 hours 25 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Kansas City/Pleasant Hill MO 659 PM CDT Sun May 7 2023 .Discussion... Issued at 317 PM CDT SUN MAY 7 2023 Key Messages: - Warm and Muggy Evening - Linear Thunderstorm Complex Late Tonight and Overnight - Warm with Isolated Showers/Storms Monday and Tuesday Discussion: The PV anomaly over the western CONUS continues to keep a troughing pattern with the axis over the Intermountain West, setting up a second day of active mid/upper-level southwesterly flow across the forecast area. The first surface cyclone has lifted with the first vorticity maximum into the Upper Mississippi River Valley. However, additional surface cyclogenesis has been ongoing across the High and Central Plains again in response to additional dCVA and WAA. The convection from last evening aided in creating a differential heating thermal boundary that started near Hwy. 36. Through this morning and afternoon, the low-level meridional flow has pushed this boundary northward, and this will continue to happen into the early evening hours. Flow between 700mb and 600mb has remained southwesterly coming from the desert southwest and Mexican Plateau. As a result, we are still seeing signs of an EML in a few our RAOB sites across the Central Plains, though not as prominent as it was yesterday afternoon. The TOP and SGF RAOBs do not have the textbook loaded gun sounding profile. However, the drier air in the 700mb and 600mb along with the weak subsidence this morning with a subtle ridge axis moving through has cleared skies across most of the area, and has even worked to clear skies in eastern Nebraska and southwest Iowa. This will be important, because insolation will provide rapid destabilization of the boundary layer across most of the warm sector of this next approaching surface cyclone for nearly the entire afternoon. Mid-level lapse rates are already between 8.0 to 8.5 C/km from Central Kansas into northern Missouri. For our area, not seeing a signal for much further cooling in the 700mb to 500mb layer, but no substantial warming either, which indicates these mid-level lapse rates will remain put in this range. With the clear skies, we are already seeing stronger mixing in the near surface layer, with temperatures in the mid 80s and dewpoints in the mid to upper 50s across most of the forecast area as of 17z. Lapse rates within the CBL steepened to nearly 9.0 C/km as of 20z this afternoon. For CAPE, mixed-layer computations were already above 1000 J/kg by 17z, had increased to nearly 2000 J/kg by 20z this afternoon. Instability will not be an issue this later this evening. H5 height falls will start in the 21-22z range this afternoon from eastern Kansas into the middle Mississippi River Valley, and phases the enhanced dCVA with the surface cyclone. With the center of the cyclone over Central Kansas, surface winds will continue to back toward the southeast most prominently for northern reaches of our CWA, and will be more south to southwesterly in central and southern portions. Hwy. 36 appears to be roughly the dividing line for backed surface winds. This will increase moisture transport into central and northern Missouri this afternoon and evening, though will have to battle stronger mixing. As this cyclone deepens and southerly flow picks up, the boundary is progged to push into central Iowa up toward the Interstate 80 corridor, leaving our area fully in the warm sector. The strongest portion of the H5 vorticity maximum will also travel from Central Kansas into west-central Iowa. As a result, the better convergence for lift will be displaced outside of our forecast area during peak diurnal heating into the early evening. This would be the lift needed to have an opportunity for surface based discrete supercells. Currently, the discrete threat is focused from eastern Nebraska into southwestern Iowa. The HRRR has continued to placed a few discrete storms north of the area where this convergence is stronger, but has kept our our counties in both Kansas and Missouri dry until much later in the evening. Most of the CAMs agree with a dry afternoon through middle evening for our counties, including the typically robust Hi-Res FV3. Will quickly point out though that mixing will erode the weak cap by late this afternoon, and there will be decent deep layer shear throughout the warm sector. Should the surface reach the convective temperature (around 93-94F in our north) a supercellular mode could be supported. Hodographs will have strong cyclonic shear in the first 1km and even first 500m. But, given the higher LCLs this afternoon with the robust and stronger surface convergence being displaced well to the north, this is a low probability outcome and as of this afternoon will not be expecting supercells in our forecast area tonight. What is anticipated, is for convection initialization in eastern Nebraska later this afternoon, and as the low-level jet kicks in, storms congeal into an MCS. Deep layer shear will remain plentiful though on both sides of the cold front with this system. 0- 6km bulk shear values will be in the realm of 45 to 55 kts by that time, and overall hodograph length and shapes (mostly straight above 3km) that support organization of the MCS into a linear storm mode. Most of the CAMs are in agreement with this evolution, though differ in the propagation speed and timing of the line moving through. There is stronger consensus for the line to expand from Central Iowa to about the Hwy. 36 corridor in Missouri. A few of the 12z CAM solutions have thunderstorm activity forming along an outflow from the MCS that goes as far south as the KC Metro and along Interstate 70. During the middle afternoon hours though, the HRRR has been backing off on southward outflow boundary convection, keeping the southern end of the line of storms to around STJ. Most of the line will be capable of severe wind gusts late this evening and overnight. The HRRR has persistently been depicting the line evolving into a bow echo, with a strong bookend vortex moving across south-central Iowa. This seems sensible, given that the better kinematic field will be located up that way closer to the thermal boundary. With that being said though, this does leave areas north of Hwy. 36 in our forecast area in a position to be impacted by a strong rear inflow jet into the system, and may even help promote bowing segments in our area resulting in enhanced straight line winds. The HRRR has been outputting wind gusts with convection across northern Missouri between 50 and 60 kts. Meanwhile, the experimental NCAR ensembles running this Spring Season have increased probabilities across a similar area in our north for wind gusts above 40 to 50 kts. Looking at the CAMs altogether via the HREF, looking at mean wind gusts around 45 kts with maximums at 60 kts. Further south of Hwy. 36 including the KC Metro, wind probabilities drop off quite a bit, but this largely is attributed to less HREF members producing convection that far south. Overall, the environment ahead of the cold front will support damaging winds, just dependent on far south the line develops (and how rapidly an outflow boundary is released). During the early afternoon, theta-e deficits from the surface to the top of the CBL were already around 15K. Some RAP and HRRR soundings are indicating this may reach between 20-25K even late into the evening across most of the warn sector. Therefore, damaging winds will have two mechanisms in which to develop with the line of storms. The first, with this kind of thermodynamic profile will be very strong cold pools. The well mixed boundary layer with nearly inverted-v soundings will support strong negative buoyancy. Second, the potential for the development of a strong rear inflow jet, especially if a bookend vortex develops northward and provides additional acceleration and bowing segments. The strengthening low-level jet could further augment this kind of process. Again, this is greatly favored along and north of Hwy. 36, and may be possible further south if an outflow boundary provides additional convergence southward into the warm sector ahead of the cold front. With the robust thermodynamics and stronger shear, there is the possibility of hail along the line. The steep mid-level lapse rates will support locally stronger updrafts along the line. Would think that the most favorable time for hail would be during the stage while storms are congealing but before becoming and organized MCS. Right now, this may occur outside of our forecast area. However, if we do have a few discrete storms that go up this evening in our area and realize the favorable wind shear, hail may be spotted with those. As noted before though, discrete storms are not greatly probable for our area unless we reach the convective temperature, which most guidance keeps us about 3 to 4 degrees shy of. As for the tornado threat, it is the same story with discrete potential. If we see a discrete supercell, it will present a tornado threat with moderately strong cyclonic curvature in the hodograph and about 150 m^2/s^2 SRH for the 0-1km layer. This outcome is more likely in Iowa and Nebraska though, closer to the warm front and the better convergence. What about QLCS tornado potential? The 0-3km shear will be between 30 and 40 kts, and mostly parallel to the line. If a bowing segment develops and orients a portion of the line perpendicular, with strong 0-3km CAPE in place, may present mesovortex generation potential. HREF members do simulate a few 2- 5km AGL Updraft Helicity Tracks within the line, but typically CAM UH tracks with linear storm modes are not overly skilled at pointing out mesovortex potential in the way they can be with supercells. Additionally, if the cold front undercuts the updrafts and the convection becomes post-frontal, this will wipe out a tornado threat. Overall, the tornado potential is highly conditional and a lower probability threat, and thus main focus should be on damaging straight line winds and overall the evolution of the line. The linear system should clear our eastern counties between 10-12z Monday morning. You will note that there is a SWODY2 marginal risk in our southeast (and a slight risk just outside our southeast). This is mainly to reflect potential for initiation of a few more cells along a remnant outflow boundary from the MCS (perhaps Bow Echo) system that could result in gusty winds and some hail. The Monday severe storm potential in our east and southeast is highly dependent on how tonight's system evolves. We may see some additional shower activity on the backside of the cold front with another vort max that ejects across the region. There is another area of surface cyclogenesis across the Front Range and High Plains that will maintain southerly flow up to about Interstate 70 in forecast area. Thus the cold front from Sunday Night and early Monday morning will not provide much relief with respect to temperatures, as WAA brings the area back up into the mid 80s. By Tuesday, the trough over the western CONUS wraps up around a few simulated closed-lows that helps to amplify a ridge across the Central CONUS. This will maintain warm temperatures through the rest of this week. Will note though that there is potential for a few short-wave perturbations to move through the flow even in the overall ridge pattern, which will bring additional chances for rain showers and thunderstorm activity. The Central to High Plains though look to be the areas more favorable for stronger thunderstorm activity in this set up though, so will hold off on more specific details for the middle of this week until this system passes through Monday morning. && .Aviation...(For the 00Z TAFS through 00Z Monday Evening) Issued at 659 PM CDT SUN MAY 7 2023 Gusty VFR conditions continue for the next few hours. A cold front approaches the region overnight lowering CIGs and bringing chances for TS across northern MO and NE KS. Confidence is fairly high in TS north of I-70; however, some uncertainties remain if TS will propagate south into the KC terminals. Winds remain southerly and gusty ahead of the frontal passage; winds then become NW behind the front. VFR conditions return afternoon. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && Discussion...Krull Aviation...Pesel
Hazardous Weather Outlook National Weather Service Kansas City/Pleasant Hill MO 334 AM CDT Sun May 7 2023 KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040- 043>046-053-054-080845- Atchison KS-Miami-Linn KS-Doniphan-Leavenworth-Wyandotte-Johnson KS- Atchison MO-Nodaway-Worth-Gentry-Harrison-Mercer-Putnam-Schuyler- Holt-Andrew-De Kalb-Daviess-Grundy-Sullivan-Adair-Buchanan-Clinton- Caldwell-Livingston-Linn MO-Macon-Platte-Clay-Ray-Carroll-Chariton- Randolph-Jackson-Lafayette-Saline-Howard-Cass-Johnson MO-Pettis- Cooper-Bates-Henry- 334 AM CDT Sun May 7 2023 This hazardous weather outlook is for northwest...north central and west central Missouri...as well as extreme eastern Kansas. .DAY ONE...Today and Tonight Strong to severe storms will be possible tonight across northeast Kansas into northern Missouri. Afternoon temperatures will rise into the upper 80s to lower 90s. Early season heat is when we see the most heat related illnesses as people may not be acclimated yet. .DAYS TWO THROUGH SEVEN...Monday through Saturday A few strong thunderstorms are possible on Monday over central Missouri. More detailed information can be accessed at... https://www.weather.gov/eax/hwo
The Omaha radar (KOAX), 127 km away, was scanning. The volume nearest the first event began at 02:24 UTC.
2 thunderstorm wind. Local standard time, as filed.
Wind gusts up to 60 mph were estimated in Tarkio as a squall line moved through town.
Roof damage was reported to a structure in Salisbury due to strong winds as the leading edge of a squall line moved through.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2023Every state in 2023This day in weather historyWarnings in Missouri, May 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1103913, 1103914.