020 ACUS01 KWNS 210102 SWODY1 SPC AC 210100 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Sat Sep 20 2025 Valid 210100Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTH-CENTRAL PLAINS... ...SUMMARY... Scattered strong to locally severe thunderstorms remain possible across parts of the south-central Plains this evening. ...South-central Plains... A few strong to locally severe storms are ongoing this evening from the TX Panhandle into western/northern OK. Moderate buoyancy remains in place across areas that have not been convectively overturned, while deep-layer shear is marginally sufficient for briefly organized storms capable of isolated severe gusts and hail. Enhanced SRH is still in place near a remnant outflow across northeast OK (as noted on the KINX VWP), and there still a window of opportunity for a supercell or two within this regime, which could pose a threat of a brief tornado and large hail. Some clustering is possible later this evening across the eastern TX Panhandle into western OK, and also across parts of the Ozarks, associated with separate branches of a modest nocturnal low-level jet. Some severe threat could persist into late evening, before convection becomes increasingly elevated overnight. ...Mid MS Valley into lower MI... A storm cluster across western lower MI has recently produced strong gusts, with other isolated strong storms noted from western IN into IL. Isolated strong storms may persist into late evening across this region within a modestly unstable environment, though a gradual weakening trend is expected with time. ...Parts of KS overnight... Guidance generally suggests that convection will increase overnight and spread eastward from northwest into central KS. MUCAPE near/above 1000 J/kg could support a few strong storms, but generally weak effective shear and modest midlevel lapse rates are expected to limit the organized severe threat. ..Dean.. 09/21/2025 $$  446 ACUS11 KWNS 210202 SWOMCD SPC MCD 210202 ARZ000-OKZ000-210400- Mesoscale Discussion 2107 NWS Storm Prediction Center Norman OK 0902 PM CDT Sat Sep 20 2025 Areas affected...parts of northeastern Oklahoma and adjacent portions of the Great Plains Concerning...Severe potential...Watch unlikely Valid 210202Z - 210400Z Probability of Watch Issuance...5 percent SUMMARY...Lingering strong thunderstorm activity may pose a continuing risk for a localized downburst or two through 10-11 PM CDT. DISCUSSION...Vigorous convective development persists in an evolving, but still not particularly organized, cluster near and northwest through north of Tulsa. Much of the stronger convection is being forced above the eastward propagating portion of an expanding cold pool at the surface, near a stalled, remnant surface frontal zone, along which low-level moisture is maximized and may be contributing to CAPE in excess of 2000 J/kg. This convection will probably gradually consolidate with a smaller immediate downstream cluster supported by lift associated with warm advection along the boundary. This is occurring in the presence of westerly deep-layer ambient mean flow on the order of 10-15 kt, with negligible deep-layer shear. However, lower/mid-tropospheric thermodynamic profiles may be unsaturated enough to contribute to a continuing risk for another strong downburst or two through late evening. ..Kerr/Bunting.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA... LAT...LON 36909590 36689502 36209455 35939481 35829521 35889565 36019602 36499658 36909590 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  887 ACUS02 KWNS 210558 SWODY2 SPC AC 210557 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 $$  837 ACUS01 KWNS 210602 SWODY1 SPC AC 210600 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...MID MS VALLEY...OH VALLEY...AND SOUTHERN GREAT LAKES...AND ALSO FROM NORTHEAST NE/SOUTHEAST SD INTO SOUTHERN MN/NORTHERN IA... ...SUMMARY... Isolated severe thunderstorms are possible later today across parts of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and southern Great Lakes. A few strong to severe thunderstorms are also possible from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Synopsis... A broad mid/upper-level trough will cover much of the central/eastern CONUS later today, with several embedded vorticity maxima expected to move across parts of the Great Plains into the Midwest and Ohio Valley. Modest midlevel flow atop a sufficiently moist and unstable environment will support some potential for strong to locally severe storms across a relatively large area. Localized corridors of somewhat greater severe threat may evolve where deep-layer shear is enhanced by one of the embedded midlevel shortwaves, as well as where midlevel flow veers to west-northwesterly across parts of the mid MO Valley and southern Plains. ...Parts of TX into southern OK... Extensive overnight convection is expected to leave a residual outflow boundary that will be located somewhere in the vicinity of north TX/southern OK by afternoon. While some midlevel warming is expected across the southern Plains through the day, relatively strong heating, and the potential influence of an MCV that may evolve from overnight convection, will support isolated to widely scattered storm development this afternoon/evening near the outflow boundary, and potentially southward along a diffuse dryline into northwest/west-central TX. Moderate buoyancy and 35-50 kt of effective shear within the northwesterly flow regime across parts of north TX into southern OK will conditionally support splitting supercells capable of producing hail and localized severe gusts. There is some uncertainty regarding the placement of the boundary by afternoon and the magnitude of any MCV-related enhancement to deep-layer shear and storm coverage, but greater probabilities may be needed if confidence increases in development of multiple supercells and/or an organized cluster within this regime. ...Northeast NE/southeast SD into southern MN/northern IA... A compact mid/upper-level low will move southeastward from eastern ND into MN later today. This low and the attendant shortwave trough will aid in the development of isolated to widely scattered storms by late afternoon or early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Relatively cool temperatures aloft, moderate buoyancy, and effective shear of 25-35 kt will support strong multicells and perhaps a couple splitting supercells. Large hail is expected to the primary hazard, though localized strong gusts will also be possible with the strongest storms. ...Eastern KS into MO... A cluster of elevated convection will likely be ongoing at the start of the period across central/eastern KS. This cluster and possibly an attendant MCV may encounter an environment across parts of MO that is recovering from a separate area of overnight convection near the Ozarks. While background midlevel flow will only support effective shear of 20-25 kt, any MCV-related enhancement to the flow would result in sufficient deep-layer shear for somewhat more organized storms. If sufficient destabilization can occur, then a few modestly organized cells or clusters may evolve this afternoon and evening, accompanied by a threat for localized damaging wind and perhaps some hail. ...Parts of the Ohio Valley and Great Lakes... Modest deep-layer southwesterly flow will overspread parts of the southern Great Lakes and Ohio Valley later today, in advance of the midlevel shortwave trough moving across the upper MS Valley. Scattered thunderstorm development is expected across the region, within a moderately unstable and weakly capped environment. Midlevel lapse rates and deep-layer shear are expected to remain relatively weak, but steepening low-level lapse rates will result in potential for cells/clusters capable of locally damaging wind this afternoon into the early evening. There is also some potential for a storm cluster or loosely organized MCS to develop across the lower MO/mid MS Valley and move toward parts of the southern Great Lakes later tonight. ..Dean/Halbert.. 09/21/2025 $$  146 ACUS02 KWNS 210617 SWODY2 SPC AC 210616 Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0116 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... CORRECTED FOR INCORRECT HAIL GRAPHIC ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 $$  876 ACUS03 KWNS 210704 SWODY3 SPC AC 210703 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CDT Sun Sep 21 2025 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTH TEXAS TO THE TENNESSEE VALLEY... ...SUMMARY... Strong to isolated severe storms are possible from the southern Plains to the Tennessee Valley. ...Discussion... A MCS will likely be ongoing somewhere across eastern Oklahoma on Tuesday morning. A moist airmass with upper 60s to low 70s dewpoints will be in place downstream of these thunderstorms. Only modest weakening of the low-level jet will occur Tuesday morning and therefore, this MCS should remain through much of the day. If sufficient destabilization can occur across Arkansas, northern Mississippi and western TN/KY, some marginal damaging wind threat could accompany this MCS as it moves east through the morning and into the afternoon. Farther west, moderate destabilization is expected across the ArkLaTex and north Texas. A cold front will strengthen/sharpen across Oklahoma and move southeast through the day. Convergence along the front, combined with weak ascent amid falling mid-level heights, will support storm development Tuesday afternoon/evening. Where stronger mid-level flow (40 to 45 knots) is present, shear will support supercells. However, it is unclear whether this stronger mid-level flow will overlap the most favorable zone for storms. Timing and amplitude of the mid-level trough remain uncertain at this time. If this stronger flow overspreads the most favorable thermodynamic zone where storms are anticipated, a Slight Risk may be justified in the ArkLaTex, but model spread remains too large at this time. ..Bentley.. 09/21/2025 $$  001 ACUS48 KWNS 210741 SWOD48 SPC AC 210740 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0240 AM CDT Sun Sep 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... A mid-level trough will amplify across the eastern CONUS on Wednesday and Thursday with differing model solutions of the trough evolution by next weekend and beyond. Regardless of the exact solution, severe weather chances should be low from Saturday and beyond as high pressure builds into the eastern CONUS and pushes moisture offshore into the Atlantic and Gulf. Some severe weather is possible across portions of the Southeast on Day 4/Wed to Day 6/Fri as moisture remains onshore ahead of the mid-level trough. ...D4/Wed - Lower Mississippi River Valley... Upper 60s to low 70s dewpoints are anticipated within the Lower Mississippi River Valley on Wednesday. A zone of moderate instability may develop within this moisture plume from Louisiana into Arkansas and Mississippi. Guidance varies greatly on the evolution of the mid-level trough as it advances east on Wednesday. This will have a significant impact on the specific location and intensity of any severe weather threat on Wednesday. However, even if a less amplified, more subdued mid-level pattern evolves, some severe weather could exist across the Lower Mississippi Valley as moderate mid-level flow overspreads moderate instability within the region. ..Bentley.. 09/21/2025  337 ACUS01 KWNS 211246 SWODY1 SPC AC 211245 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Sun Sep 21 2025 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS AND SOUTHERN OKLAHOMA... ...SUMMARY... Large hail may occur with supercells that develop this afternoon across parts of north Texas and southern Oklahoma. Isolated strong to severe thunderstorms are possible this afternoon and evening across a broad portion of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and Great Lakes, and also from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Southern Plains into the Ozarks and Mid Mississippi Valley... Showers and thunderstorms are ongoing this morning across parts of western/central OK and western north TX in association with a weak MCV and modest low-level warm/moist advection. Convectively reinforced outflow from this morning activity should be draped along/near the Red River this afternoon, with a rich low-level moisture present to its south. Northwesterly mid/upper-level flow should gradually strengthen through the day across north TX/southern OK as a weak mid-level perturbation moves southeastward from the southern/central High Plains. A favorable combination of moderate instability aided by modestly steepened mid-level lapse rates and daytime heating, along with 35-45 kt of deep-layer shear, will likely prove favorable for thunderstorm organization. Most guidance suggests multiple thunderstorms will develop and become supercellular this afternoon across parts of north TX and southern OK. Scattered severe hail should be the main threat with this convection as it spreads southeastward through the early evening. Strengthening MLCIN with time this evening should result in a weakening trend as this activity approaches the DFW metroplex, but isolated large hail and gusty winds will remain possible until convection dissipates. Given increased confidence in supercells developing, have added a focused Slight Risk for large hail with this update. Weak mid-level troughing with multiple embedded perturbations will move eastward today across the central Plains into the Ozarks and mid MS Valley. One notable MCV with ongoing convection is also noted this morning across central KS. Filtered diurnal heating should aid in the development of weak to locally moderate instability this afternoon along/south of a front that should be draped across northern KS/MO. As modest large-scale ascent overspreads the warm sector, at least scattered thunderstorms are forecast to develop this afternoon in a weakly sheared environment, with modest enhancement provided by the eastward-moving MCV across MO. Isolated hail and damaging winds may occur with the stronger cores, with some potential for eventual clustering towards the MS River by early evening. ...Midwest/Great Lakes... A broad zone of modest (20-30 kt) west-southwesterly mid-level flow will be maintained today over much of the Midwest/Great Lakes, on the southeast periphery of weak upper troughing over the Upper Midwest. Recent visible satellite imagery across these regions show generally widespread cloudiness, which may hinder diurnal destabilization to some extent. Mid-level lapse rates are also expected to remain rather poor (reference ILX/ILN/DTX observed 12Z soundings). Even with these thermodynamic limitations, it still appears possible that isolated damaging winds could occur with any thunderstorms that can develop this afternoon and spread generally east-northeastward. This activity should quickly weaken this evening with the loss of daytime heating. ...Mid Missouri Valley into Southern Minnesota/Northern Iowa... A compact mid/upper-level low will move southeastward from eastern ND into MN today. This low and attendant shortwave trough may aid in the development of isolated to widely scattered storms by early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Cool temperatures aloft, weak to moderate instability, and effective bulk shear around 25-35 kt should support multicells and perhaps a couple splitting supercells. Hail is expected to the primary severe hazard with any thunderstorms that can be sustained, but confidence in this occurring before this evening is low. ..Gleason/Grams.. 09/21/2025 $$  985 ACUS01 KWNS 211622 SWODY1 SPC AC 211621 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Sun Sep 21 2025 Valid 211630Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS AND SOUTHERN OKLAHOMA... ...SUMMARY... Large hail and severe gusts may occur with supercells that develop this afternoon across parts of north Texas and southern Oklahoma. ...Southern Plains into the Ozarks and Mid Mississippi Valley... Radar mosaic data this morning shows a pair of MCVs moving slowly east over central KS and OK and immediately downstream of an impulse moving east-southeastward (per water-vapor imagery) from the central High Plains towards the lower MO Valley. Considerable cloud cover persists from the Red River northward into the lower MO Valley in association with overnight and morning convection. Surface analysis places an outflow boundary across north TX to the south of ongoing elevated storms near the Red River. Along and to the south of the boundary, rich low-level moisture coupled with heating will lead to moderate destabilization by mid afternoon. The glancing influence of the MCV combined with the low-level convergence along the outflow boundary will probably lead to widely scattered to scattered storms developing by mid-late afternoon over the Red River Valley. Elongated hodographs due to 70-kt northwesterly high-level flow will favor supercellular organization with the stronger updrafts. Large hail and severe gusts appear to be the primary threats with this activity through the early evening before the severe threat likely diminishes after sunset. Farther north, weak mid-level troughing with multiple embedded perturbations will move eastward across the central Plains into the Ozarks and mid MS Valley. Heating will likely be greatest across MO ahead of the aforementioned KS MCV with weak to locally moderate instability this afternoon along/south of a front that should be draped across northern KS/MO. As modest large-scale ascent overspreads the warm sector, at least scattered thunderstorms are forecast to develop this afternoon in a weakly sheared environment, with modest enhancement provided by the eastward-moving MCV across MO. Isolated hail and damaging winds may occur with the stronger cores, with some potential for eventual clustering towards the MS River by early evening. ...Midwest/Great Lakes... A broad zone of modest (20-30 kt) west-southwesterly mid-level flow will be maintained today over much of the Midwest/Great Lakes, on the southeast periphery of weak upper troughing over the Upper Midwest. Diurnal heating of a seasonably moist airmass will lead to isolated to widely scattered storms eventually developing late this afternoon into the evening. Somewhat poor mid-level lapse rates will likely stunt storm intensity, but a few widely spaced damaging gusts cannot be ruled out within this general corridor. This activity should quickly weaken this evening with the loss of heating. ...Mid Missouri Valley into Southern Minnesota/Northern Iowa... A compact mid/upper-level low will continue to migrate eastward across the Upper Midwest through early Monday morning. This low and attendant shortwave trough may aid in the development of isolated to widely scattered storms by early evening from southern MN into northeast NE in the vicinity of a weak surface boundary. Forecast soundings show some modest enhancement to the hodograph by early evening, which may yield a couple of stronger storms. Multicells or transient supercell structures are possible with the strongest cells and an accompanying isolated risk for severe may occur before this activity weakens by late evening. ..Smith/Wendt.. 09/21/2025 $$  648 ACUS02 KWNS 211740 SWODY2 SPC AC 211739 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 PM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA... THE EASTERN TEXAS/OKLAHOMA PANHANDLES... AND SOUTHEASTERN NEBRASKA INTO SOUTHWESTERN IOWA/NORTHWESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central/southern High Plains and the low to mid Missouri Valley. ...Synopsis... A broad troughing pattern with two embedded upper-lows will be in place from the Northern Rockies into the Great Lakes region, with high pressure building in across the West. A diffuse frontal boundary will extend from the upper Great Lakes region into the central High Plains. Much of the central/southern Plains is expected to remain strongly capped through much of the day, with late thunderstorm development expected as the front shifts southward overnight. ...Central and Southern Plains... Convection will move across Oklahoma late in the D1 period on Sunday. In the wake of this convection, appreciable MLCIN is expected across much of western Oklahoma into Kansas. Strong daytime heating is expected under broken mid to high level clouds. Daytime temperatures are expected to get into the mid to upper 80s with convective temps approaching and exceeding 90 F. This should delay thunderstorm development into the evening as the cooling from the upper wave and cold front approach from the west. Given the late development and linear forcing, mode is likely to be linear/MCS with potential for hail early on with any more discrete cells that can form along and ahead of the front in western Kansas. A southerly low-level jet is expected to steadily increase through the evening, with low level curvature of the hodographs noted from 00z onward. This may support embedded circulations within the more linear mode and potential for some tornado risk overnight. For now, confidence is low in a tornado risk developing because of the late timing of the upper wave and mode concerns. A Slight Risk was maintained and expanded eastward into eastern/northern Oklahoma with this outlook. ...NE/IA to Lake Michigan... Thunderstorm development is expected in the afternoon across the diffuse boundary from Nebraska to the Lake Michigan region. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. Confidence is greater in coverage of storms and more concentrated severe risk across portions of eastern Nebraska into southern Iowa. While deep layer shear will be modest around 20-30 kts, a few instances of large hail may be possible across eastern Nebraska before a transition to more of a damaging wind threat. A Slight Risk was added to account for this risk. ...Tennessee Valley to the Lower Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped air mass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 20 to 30 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Thornton.. 09/21/2025 $$  858 ACUS11 KWNS 211824 SWOMCD SPC MCD 211824 OHZ000-KYZ000-212030- Mesoscale Discussion 2108 NWS Storm Prediction Center Norman OK 0124 PM CDT Sun Sep 21 2025 Areas affected...Southern into eastern Ohio Concerning...Severe potential...Watch unlikely Valid 211824Z - 212030Z Probability of Watch Issuance...5 percent SUMMARY...A northeasterly moving cluster of storms may produce isolated wind damage as low-level lapse rates become more favorable this afternoon. DISCUSSION...A weak MCV in northern Kentucky has promoted the development of a small cluster of storms in southern Ohio. This activity is expected to move northeast through the afternoon. The morning observed sounding from Wilmington suggests that MLCIN has just now eroded as temperatures have risen into the low/mid 80s F. Continued heating should steepen low-level lapse rates further. The KILN VAD shows under 20 kts of 0-6 km shear and the mid-level lapse rates observed on the sounding were also quite modest (~6 C/km). Without stronger low-level flow or more robust updrafts, the potential for wind damage with this cluster is likely to remain spatially and temporally limited. ..Wendt/Smith.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PBZ...RLX...CLE...JKL...ILN... LAT...LON 38448389 39128454 39898397 41178249 41208158 40758133 39348222 38498318 38448389 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH  471 ACUS03 KWNS 211928 SWODY3 SPC AC 211927 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Sun Sep 21 2025 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEASTERN OKLAHOMA...NORTHEASTERN TEXAS...SOUTHWESTERN ARKANSAS... ...SUMMARY... Strong to severe storms are possible from the southern Plains to the Tennessee Valley. Strongest thunderstorm activity is expected across southeastern Oklahoma into northeastern Texas and southwestern Arkansas, where supercells with large hail and damaging wind are possible by the afternoon. ...Discussion... A cold front moving across the central/southern Plains will sharpen as it moves eastward across the lower Missouri and Mississippi Valleys. It is likely that convection will be ongoing along this feature at the start of the period across central Oklahoma. Storms will gradually shift eastward through the day across portions of Arkansas into western Tennessee and along the Red River. Activity is expected to be ongoing across central Oklahoma at the start of the period, with a eastward advancing MCS in progress. The low-level jet is expected to remain strong into the morning on Tuesday, which will likely support maintenance of some damaging wind risk into the morning. Depending on how much destabilization can occur downstream across Arkansas into western Tennessee, the damaging wind threat may continue eastward through the afternoon. A reservoir of higher MLCAPE (around 2000-3000 J/kg) may reside near the Red River, with an increase in storm intensity by late morning/early afternoon along the front. Sufficient deep layer shear should be in place will support supercell structures, although a mixed mode of multi-cell clusters is expected with time with potential for large hail and damaging wind. A 15% area was added with this outlook to account for this risk. ..Thornton.. 09/21/2025 $$  161 ACUS01 KWNS 212000 SWODY1 SPC AC 211959 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Sep 21 2025 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS INTO SOUTHERN OKLAHOMA... ...SUMMARY... Large hail and severe gusts may occur with supercells that develop this afternoon across parts of north Texas and southern Oklahoma. ...20z Update... The previous forecast largely remains on track with only minor modifications outlined below. ...Ozarks... 5% wind probabilities were slightly expanded across northern AR/southeast MO to better align with the expected trajectory of developing upstream convection across northeast OK/northwest AR, which should spread east/northeast through mid-evening based on latest CAM guidance. Loosely organized clusters appear probable, and deep-layer shear should be adequate (around 20-25 knots) for periodic intensification with an attendant threat for strong/severe winds. ...Mid Missouri Valley into Southern Minnesota/Northern Iowa... Severe risk probabilities were trimmed across portions of eastern SD/northeast NE based on latest surface obs/satellite data that shows the best low-level convergence across far eastern SD/far southwest MN. Correspondingly, time-lagged CAM ensemble guidance suggests the highest probability for strong/severe storms will reside mainly across southwest MN/northwest IA this evening. ...Southern Oklahoma/northern Texas... Latest surface analysis reveals multiple boundaries draped across the Red River Valley region to the east of a weak surface low over the Rolling Plains of northwest TX. Lingering convection from this morning near the I-35 corridor has persisted longer than anticipated, which has stunted diurnal heating across portions of the Red River Valley to some degree. It remains unclear exactly which boundary will be most influential for thunderstorm development, which may have implications for storm mode/evolution. However, strong heating to the south of the outflow boundaries combined with glancing ascent from the passing MCV over central OK should still promote at least isolated to scattered convection by mid-evening. ..Moore.. 09/21/2025 .PREV DISCUSSION... /ISSUED 1121 AM CDT Sun Sep 21 2025/ ...Southern Plains into the Ozarks and Mid Mississippi Valley... Radar mosaic data this morning shows a pair of MCVs moving slowly east over central KS and OK and immediately downstream of an impulse moving east-southeastward (per water-vapor imagery) from the central High Plains towards the lower MO Valley. Considerable cloud cover persists from the Red River northward into the lower MO Valley in association with overnight and morning convection. Surface analysis places an outflow boundary across north TX to the south of ongoing elevated storms near the Red River. Along and to the south of the boundary, rich low-level moisture coupled with heating will lead to moderate destabilization by mid afternoon. The glancing influence of the MCV combined with the low-level convergence along the outflow boundary will probably lead to widely scattered to scattered storms developing by mid-late afternoon over the Red River Valley. Elongated hodographs due to 70-kt northwesterly high-level flow will favor supercellular organization with the stronger updrafts. Large hail and severe gusts appear to be the primary threats with this activity through the early evening before the severe threat likely diminishes after sunset. Farther north, weak mid-level troughing with multiple embedded perturbations will move eastward across the central Plains into the Ozarks and mid MS Valley. Heating will likely be greatest across MO ahead of the aforementioned KS MCV with weak to locally moderate instability this afternoon along/south of a front that should be draped across northern KS/MO. As modest large-scale ascent overspreads the warm sector, at least scattered thunderstorms are forecast to develop this afternoon in a weakly sheared environment, with modest enhancement provided by the eastward-moving MCV across MO. Isolated hail and damaging winds may occur with the stronger cores, with some potential for eventual clustering towards the MS River by early evening. ...Midwest/Great Lakes... A broad zone of modest (20-30 kt) west-southwesterly mid-level flow will be maintained today over much of the Midwest/Great Lakes, on the southeast periphery of weak upper troughing over the Upper Midwest. Diurnal heating of a seasonably moist airmass will lead to isolated to widely scattered storms eventually developing late this afternoon into the evening. Somewhat poor mid-level lapse rates will likely stunt storm intensity, but a few widely spaced damaging gusts cannot be ruled out within this general corridor. This activity should quickly weaken this evening with the loss of heating. ...Mid Missouri Valley into Southern Minnesota/Northern Iowa... A compact mid/upper-level low will continue to migrate eastward across the Upper Midwest through early Monday morning. This low and attendant shortwave trough may aid in the development of isolated to widely scattered storms by early evening from southern MN into northeast NE in the vicinity of a weak surface boundary. Forecast soundings show some modest enhancement to the hodograph by early evening, which may yield a couple of stronger storms. Multicells or transient supercell structures are possible with the strongest cells and an accompanying isolated risk for severe may occur before this activity weakens by late evening. $$  437 ACUS11 KWNS 212004 SWOMCD SPC MCD 212003 ARZ000-TXZ000-OKZ000-212200- Mesoscale Discussion 2109 NWS Storm Prediction Center Norman OK 0303 PM CDT Sun Sep 21 2025 Areas affected...Eastern Oklahoma...western Arkansas...and far northeast Texas Concerning...Severe potential...Watch unlikely Valid 212003Z - 212200Z Probability of Watch Issuance...20 percent SUMMARY...A couple strong storms may pose a risk of locally damaging gusts and possibly marginal hail through the afternoon. DISCUSSION...The latest water-vapor imagery shows a convectively augmented midlevel trough moving slowly eastward across central OK, while an accompanying MCV and related outflow boundary continue eastward across eastern OK. Despite substantial cloud coverage ahead of the trough, the boundary layer has warmed into the 80s amid upper 60s/lower 70s dewpoints (contributing to moderate surface-based buoyancy) in the vicinity of the outflow boundary. While the SRX/INX VWPs are only showing around 20 kt of 0-6 km shear, this should continue strengthening to around 30 kt as stronger midlevel flow accompanying the trough (sampled by TLX VWP) overspreads the area. This may support a couple loosely organized clusters capable of producing locally damaging gusts and possibly marginal hail through the afternoon. ..Weinman/Smith.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SHV...TSA...FWD...OUN... LAT...LON 34179605 34729601 35409575 35779577 36109565 36429536 36509483 36439412 35899380 34989385 34279421 33669467 33539518 33749581 34179605 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  185 ACUS11 KWNS 212046 SWOMCD SPC MCD 212046 OKZ000-TXZ000-212245- Mesoscale Discussion 2110 NWS Storm Prediction Center Norman OK 0346 PM CDT Sun Sep 21 2025 Areas affected...Parts of north Texas and far south-central OK Concerning...Severe potential...Watch possible Valid 212046Z - 212245Z Probability of Watch Issuance...60 percent SUMMARY...Severe risk will increase over the next few hours. The primary concerns will be large hail and severe wind gusts. A watch may be needed for parts of the area. DISCUSSION...The latest surface observations and visible satellite imagery indicate a remnant outflow boundary shifting slightly northward in north-central TX -- potentially in response to an evolving surface low over the Rolling Plains. Boundary-layer cumulus is deepening along the outflow boundary, and isolated convective initiation is underway. Ample diurnal heating/destabilization amid upper 60s/lower 70s dewpoints and steep midlevel lapse rates are contributing to moderate surface-based buoyancy. This buoyancy and around 50 kt of effective shear (with enhanced low-level clockwise curvature) should initially favor a couple semi-discrete supercells -- with a risk of large hail and locally severe wind gusts. With time, storms may congeal into clusters while tracking east-southeastward, which would promote an increasing severe-wind risk. While the primary concern for severe storms is in north TX, a couple strong to severe storms capable of producing large hail will remain possible across southern OK. While storm coverage and the spatial extent of the threat is somewhat uncertain, a watch may be needed for parts of the area. ..Weinman/Smith.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...SJT...LUB... LAT...LON 32629696 32339782 32199894 32349948 32839993 33260002 33589983 33819899 34089796 34579706 34599647 34159610 33469638 32629696 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN  875 ACUS11 KWNS 212134 SWOMCD SPC MCD 212133 MNZ000-IAZ000-SDZ000-212300- Mesoscale Discussion 2111 NWS Storm Prediction Center Norman OK 0433 PM CDT Sun Sep 21 2025 Areas affected...portions of southeastern South Dakota into far southwestern Minnesota and extreme northwestern Iowa Concerning...Severe potential...Watch unlikely Valid 212133Z - 212300Z Probability of Watch Issuance...20 percent SUMMARY...Scattered thunderstorms may continue to increase in coverage and intensity through the remainder of the afternoon. The strongest storms may produce an instance of marginally severe wind/hail or a brief tornado. DISCUSSION...Scattered multicellular storms have developed amid peak heating and are gradually increasing in coverage with the passage of a pronounced 500 mb shortwave trough/vorticity maximum to the north. These storms are developing atop a mixed boundary layer, but with relatively mediocre mid-level lapse rates (e.g. around 6 C/km). As such, buoyancy is weak, with about 500-1000 J/kg MLCAPE constrained to tall, thin profiles per RAP forecast soundings. Deep-layer shear is not strong, with 20-30 kts of effective bulk shear noted per 21Z mesoanalysis. Nonetheless, appreciable turning of the winds with height, along with some strengthening, is supporting low-level hodographs with some curvature. Multicells will therefore remain the primary mode of convection of the more mature storms that become sustained, though a transient supercell or two is possible. A couple instances of marginally severe hail, wind, or a brief tornado cannot be ruled out. ..Squitieri/Kerr.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX...DMX...FSD... LAT...LON 44079730 44979470 45039377 44779305 44339277 43889280 43499314 43149395 43049506 43129603 43299670 43529699 44079730 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  516 ACUS11 KWNS 212144 SWOMCD SPC MCD 212143 ILZ000-MOZ000-212315- Mesoscale Discussion 2112 NWS Storm Prediction Center Norman OK 0443 PM CDT Sun Sep 21 2025 Areas affected...portions of northeastern Missouri into central Illinois Concerning...Severe potential...Watch unlikely Valid 212143Z - 212315Z Probability of Watch Issuance...5 percent SUMMARY...A damaging gust or two may occur with merging storms over the next few hours. DISCUSSION...Scattered pulse-cellular and multicellular storms, which have been ongoing for the past few hours, are showing signs of merging. Furthermore, increasing lightning trends suggests that some of these storms may be intensifying. Vertical wind shear is poor, though up to 2000 J/kg MLCAPE precede the clustering storms per 21Z mesoanalysis. As such, the amalgamation of storms may result in strong enough cold pool mergers and subsequent outflow to support a damaging gust or two through the remainder of the afternoon. ..Squitieri/Kerr.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILX...LSX...EAX... LAT...LON 39469303 40099119 40289022 40118966 39808917 39418896 39008925 38828970 38719025 38569087 38499134 38479189 39469303 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH  948 ACUS11 KWNS 212248 SWOMCD SPC MCD 212247 OKZ000-TXZ000-220045- Mesoscale Discussion 2113 NWS Storm Prediction Center Norman OK 0547 PM CDT Sun Sep 21 2025 Areas affected...Southern Plains Concerning...Severe Thunderstorm Watch 616... Valid 212247Z - 220045Z The severe weather threat for Severe Thunderstorm Watch 616 continues. SUMMARY...Strong-severe thunderstorm clusters will continue propagating southeast across ww616. Wind and hail remain the primary threats. DISCUSSION...Water-vapor imagery depicts a well-defined midlevel vort over northeast OK digging southeast toward northwest AR. Southwestern influence of the associated trough appears to be aiding multiple thunderstorm clusters across portions of north Texas into extreme south central Oklahoma. Strong boundary-layer heating has proven instrumental in destabilization near the frontal zone and 0-3km lapse rates are quite steep across north Texas. Latest MRMS data suggests at least three robust updrafts are likely generating large hail, one over eastern Young County, northern Denton County, and southeast Grayson County. Northwesterly flow is gradually strengthen over the next several hours, so this activity should continue propagating southeast toward the I-20 corridor, including the Metroplex. Hail and wind can be expected with the strongest storms. ..Darrow.. 09/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...SJT... LAT...LON 33329997 34459622 33149621 32009997 33329997 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN