Severe Storms

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 PM CDT Wed Sep 18 2024 Valid 190100Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A NARROW ZONE FROM THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY INTO THE CENTRAL PLAINS... ...SUMMARY... Isolated strong storms are possible this evening over parts of the central Plains, and from the Red River into the upper Mississippi Valley overnight. ...Northern Plains/Upper MS Valley... Cooling aloft with an upper trough will continue eastward across the Dakotas and into MN, with a cold front pushing east and providing a focus for possible storm development. Convection is now forming within a narrow instability axis over eastern ND, and some of the cells could eventually produce severe hail. Additional activity may occur farther south as well, although coverage is less certain. Cool air aloft with veering winds with height will tend to favor sporadic hail. For more information see mesoscale discussion 2085. ...Central Plains... Warm temperatures and peak heating has led to isolated storms along a retreating dryline from south-central KS into the eastern TX Panhandle. While capping should eventually result in dissipation in a couple hours, marginal hail or locally strong gusts will be possible in the near term. ..Jewell.. 09/19/2024 Read more

MD 2085 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHEASTERN NORTH DAKOTA INTO FAR NORTHWESTERN MINNESOTA
Mesoscale Discussion 2085 NWS Storm Prediction Center Norman OK 0634 PM CDT Wed Sep 18 2024 Areas affected...Portions of northeastern North Dakota into far northwestern Minnesota Concerning...Severe potential...Watch unlikely Valid 182334Z - 190100Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe storms capable of large hail and locally severe gusts cannot be ruled out during the next few hours. A watch is not expected. DISCUSSION...Attempts at convective initiation are underway across portions of northeastern ND, focused within a north/south-oriented confluence band, and near an antecedent differential heating zone. This activity may be aided by a lobe of midlevel ascent (evident in water-vapor imagery) rotating around the eastern periphery of a midlevel low over eastern MT. Middle/upper 60s dewpoints beneath a plume of steep midlevel lapse rates are contributing to moderate surface-based instability ahead of the developing storms. Additionally, regional VWP depicts a long hodograph with modest low-level hodograph curvature -- characterized by around 45 kt of effective shear. Given subtle mesoscale forcing, storm maturation is uncertain (especially given increasing nocturnal static stability), though the aforementioned parameter space will conditionally support a couple organized storms/supercells capable of producing large hail and locally severe gusts. Any severe threat here is expected to remain too isolated for a watch at this time. ..Weinman/Hart.. 09/18/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 47429858 47399898 47609941 47889981 48140007 48590026 48940030 49090015 49159962 49169781 49089698 48839669 48129670 47719702 47429858 Read more

No watches are valid as of Wed Sep 18 23:37:02 UTC 2024.

MD 2085 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHEASTERN NORTH DAKOTA INTO FAR NORTHWESTERN MINNESOTA
Mesoscale Discussion 2085 NWS Storm Prediction Center Norman OK 0634 PM CDT Wed Sep 18 2024 Areas affected...Portions of northeastern North Dakota into far northwestern Minnesota Concerning...Severe potential...Watch unlikely Valid 182334Z - 190100Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe storms capable of large hail and locally severe gusts cannot be ruled out during the next few hours. A watch is not expected. DISCUSSION...Attempts at convective initiation are underway across portions of northeastern ND, focused within a north/south-oriented confluence band, and near an antecedent differential heating zone. This activity may be aided by a lobe of midlevel ascent (evident in water-vapor imagery) rotating around the eastern periphery of a midlevel low over eastern MT. Middle/upper 60s dewpoints beneath a plume of steep midlevel lapse rates are contributing to moderate surface-based instability ahead of the developing storms. Additionally, regional VWP depicts a long hodograph with modest low-level hodograph curvature -- characterized by around 45 kt of effective shear. Given subtle mesoscale forcing, storm maturation is uncertain (especially given increasing nocturnal static stability), though the aforementioned parameter space will conditionally support a couple organized storms/supercells capable of producing large hail and locally severe gusts. Any severe threat here is expected to remain too isolated for a watch at this time. ..Weinman/Hart.. 09/18/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 47429858 47399898 47609941 47889981 48140007 48590026 48940030 49090015 49159962 49169781 49089698 48839669 48129670 47719702 47429858 Read more

No Mesoscale Discussions are in effect as of Wed Sep 18 22:46:02 UTC 2024.

MD 2084 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR THE EASTERN TEXAS PANHANDLE INTO NORTHWEST OKLAHOMA AND SOUTHERN KANSAS
Mesoscale Discussion 2084 NWS Storm Prediction Center Norman OK 0342 PM CDT Wed Sep 18 2024 Areas affected...The eastern Texas Panhandle into northwest Oklahoma and southern Kansas Concerning...Severe potential...Watch unlikely Valid 182042Z - 182245Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorm development is expected by late afternoon/early evening across the eastern Texas Panhandle and into adjacent portions of northwest Oklahoma and southern Kansas. Thunderstorm coverage should remain sufficiently isolated to preclude watch issuance, but instances of severe hail/wind will be possible. DISCUSSION...Latest GOES imagery shows deepening cumulus along a weakly confluent surface trough across the TX Panhandle into southern KS. The southerly flow regime across the region has helped offset the influence of diurnal mixing with dewpoints remaining the low to mid 60s. Concurrently, temperatures are warming into the low to mid 90s, which is eroding inhibition and supporting MLCAPE upwards of around 1000 J/kg. Any further improvements to the thermodynamic environment will be modest through late afternoon, namely in the form of steepening low-level lapse rates as temperatures peak in the mid to upper 90s. However, nearly zonal 30-35 knot flow aloft is supporting somewhat elongated mid-level hodographs with similar effective bulk shear values. This kinematic environment should support organized convection, including the potential for a supercell or two with an attendant risk for large hail (most likely up to 1.0-1.75 inches in diameter) and severe winds. Based on the aforementioned satellite trends, at least a couple of storms appear probable, but the fairly weak forcing for ascent along the surface trough and stronger inhibition downstream into OK and KS suggests that storm coverage and duration may be limited. Consequently, watch issuance is unlikely. ..Moore/Gleason.. 09/18/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...OUN...DDC...LUB...AMA... LAT...LON 35020160 36810046 37789985 38129965 38369910 38379879 38259853 38039837 37809827 37549819 37309817 37039825 36739841 36279872 35839903 35389952 34999987 34700026 34590067 34620121 34670144 34850167 35020160 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0430 PM CDT Wed Sep 18 2024 Valid 201200Z - 261200Z An active mid-level flow regime is expected across the CONUS over the next seven days. Troughing over the western US will gradually move eastward as an embedded speed max passes over the Southern Rockies/Plains this weekend with gusty winds and dry conditions. By early next week, troughing will move over the central CONUS favoring cooler and wetter conditions. At the same time, ridging should redevelop to the west. Some potential for easterly offshore winds could develop over parts of CA and OR early next week, but significant forecast uncertainty is present in the medium range. This suggests the threat for fire-weather conditions is relatively low. ...Southern Plains... As troughing gradually moves eastward, stronger southwesterly flow aloft will overspread parts of the Southern Rockies/Plains late this week and into the first half of the weekend. A lee low will quickly deepen over eastern CO supporting periods of gusty downlope winds, with gusts of 25-30 mph. However, moisture return ahead of the low will favor higher RH values. Additionally, recent precipitation has likely tempered fuels somewhat, with more precipitation likely in into this weekend. Thus, while some risk for fire-weather conditions may develop over the Plains, confidence is low. ..Lyons.. 09/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2083 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF EASTERN SOUTH DAKOTA...ADJACENT NORTHEASTERN NEBRASKA AND SOUTHWESTERN MINNESOTA
Mesoscale Discussion 2083 NWS Storm Prediction Center Norman OK 0253 PM CDT Wed Sep 18 2024 Areas affected...parts of eastern South Dakota...adjacent northeastern Nebraska and southwestern Minnesota Concerning...Severe potential...Watch possible Valid 181953Z - 182230Z Probability of Watch Issuance...40 percent SUMMARY...The initiation of one or two strong storms appears possible late this afternoon. Sustained storm development may include the evolution of supercell structures posing a risk for severe hail, and perhaps some potential for a tornado by early evening. Due to the isolated nature, it is not certain that a severe weather watch is needed, but trends are being monitored. DISCUSSION...Although stronger mid-level height falls appear to be shifting to the north, a destabilizing warm sector boundary layer across the eastern South Dakota vicinity will remain beneath weakly difluent cyclonic mid-level flow into early evening. With mixed-layer CAPE now on the order of 1500 J/kg, beneath 30-50 kt southwesterly mid/upper flow, the environment appears at least conditionally supportive of supercells, and low-level hodographs may enlarge with clockwise curvature as southerly flow around 850 mb is forecast to strengthen some (to around 30+ kt) through 22-00Z. Although low-level forcing for sustained convective development remains unclear, weak warm advection to the east of the dryline may be supporting ongoing attempts at deepening convection east of Huron into the Watertown vicinity. And objective analysis has indicated a persistent localized area of enhanced convergence along a confluence zone near/west of Yankton. Model output, including the convection allowing guidance, suggest that probabilities for thunderstorm development are generally low into early evening. However, the initiation of one or two storms appears possible. If this is sustained, this may include the evolution of supercell structures posing a risk for severe hail, and perhaps some potential for a tornado. ..Kerr/Gleason.. 09/18/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...FSD...OAX...ABR...LBF... LAT...LON 45389647 44609622 42819716 42949859 44379830 45219788 45549726 45389647 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Sep 18 2024 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST NEBRASKA INTO FAR NORTHWEST IOWA...EASTERN SOUTH DAKOTA...AND WESTERN MINNESOTA... ...SUMMARY... Thunderstorms capable of producing severe wind gusts and large hail are possible today across parts of the eastern Dakotas and Minnesota into the mid Missouri Valley. A marginal severe threat will also extend southward into parts of the central and southern Plains. ...20Z Update... No changes were made to the ongoing forecast. For mesoscale details concerning eastern South Dakota and vicinity, see MCD 2083. Additional details can be found in the previous discussion below. ..Wendt.. 09/18/2024 .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Sep 18 2024/ ...Northern Plains/Upper Midwest to the Southern High Plains... A closed upper low centered over eastern MT will continue northeastward during the period, reaching southeast SK by early Thursday morning. Upper-level ridging extending northward from the northwest Gulf Coast into the upper MS Valley will slowly shift eastward to the Upper Great Lakes. A belt of enhanced southwesterly mid-level flow will extend from southern CA through the central High Plains, while also wrapping cyclonically through the eastern Dakotas and into southern Canada. At the surface, a trough/front extends southward from central ND into SD and western NE, before continuing southwestward over the central/southern High Plains. This boundary may serve as a focus for renewed thunderstorm development later today. A band of elevated convection has generally moved northward from northeast ND and northwest MN into southern MB. In the wake of this activity, cloud cover remains prevalent across much of the warm sector across the northern Plains/Upper Midwest. Still, filtered daytime heating of an adequately moist boundary layer should aid in the development of around 1500-2000 J/kg of MLCAPE by late afternoon. Isolated to scattered thunderstorms may form along/east of the surface trough/front within a favorable zone of 30-40 kt of effective bulk shear. But, better large-scale forcing associated with the upper low over the northern High Plains will tend to remain displaced north and west (in southern Canada). Accordingly, 12Z high-resolution guidance continues to vary regarding storm coverage across the Slight Risk (isolated versus scattered) given the weaker forcing aloft. Even with this continued uncertainty, various NAM/RAP forecast soundings still suggest a somewhat conditional risk for organized storms (mix of multicells and supercells). Severe hail/wind may accompany the stronger storms from late afternoon through early evening, before this activity eventually weakens. Further south into the central/southern Plains, low-levels are forecast to be somewhat drier near the surface trough, with surface dewpoints expected to mostly range in the upper 50s to low 60s by late afternoon with pronounced boundary-layer mixing. Warmer mid-level temperatures and limited large-scale ascent across these regions should temper the overall intensity of any updrafts that can form and be sustained, and resultant intensity/coverage of this convection. Still, some guidance shows locally greater thunderstorm coverage and resulting isolated severe wind threat from the eastern TX Panhandle into far northwest OK and southern KS during the late afternoon/early evening, where low-level lapse rates should be maximized with robust daytime heating. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Sep 18 2024 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST NEBRASKA INTO FAR NORTHWEST IOWA...EASTERN SOUTH DAKOTA...AND WESTERN MINNESOTA... ...SUMMARY... Thunderstorms capable of producing severe wind gusts and large hail are possible today across parts of the eastern Dakotas and Minnesota into the mid Missouri Valley. A marginal severe threat will also extend southward into parts of the central and southern Plains. ...20Z Update... No changes were made to the ongoing forecast. For mesoscale details concerning eastern South Dakota and vicinity, see MCD 2083. Additional details can be found in the previous discussion below. ..Wendt.. 09/18/2024 .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Sep 18 2024/ ...Northern Plains/Upper Midwest to the Southern High Plains... A closed upper low centered over eastern MT will continue northeastward during the period, reaching southeast SK by early Thursday morning. Upper-level ridging extending northward from the northwest Gulf Coast into the upper MS Valley will slowly shift eastward to the Upper Great Lakes. A belt of enhanced southwesterly mid-level flow will extend from southern CA through the central High Plains, while also wrapping cyclonically through the eastern Dakotas and into southern Canada. At the surface, a trough/front extends southward from central ND into SD and western NE, before continuing southwestward over the central/southern High Plains. This boundary may serve as a focus for renewed thunderstorm development later today. A band of elevated convection has generally moved northward from northeast ND and northwest MN into southern MB. In the wake of this activity, cloud cover remains prevalent across much of the warm sector across the northern Plains/Upper Midwest. Still, filtered daytime heating of an adequately moist boundary layer should aid in the development of around 1500-2000 J/kg of MLCAPE by late afternoon. Isolated to scattered thunderstorms may form along/east of the surface trough/front within a favorable zone of 30-40 kt of effective bulk shear. But, better large-scale forcing associated with the upper low over the northern High Plains will tend to remain displaced north and west (in southern Canada). Accordingly, 12Z high-resolution guidance continues to vary regarding storm coverage across the Slight Risk (isolated versus scattered) given the weaker forcing aloft. Even with this continued uncertainty, various NAM/RAP forecast soundings still suggest a somewhat conditional risk for organized storms (mix of multicells and supercells). Severe hail/wind may accompany the stronger storms from late afternoon through early evening, before this activity eventually weakens. Further south into the central/southern Plains, low-levels are forecast to be somewhat drier near the surface trough, with surface dewpoints expected to mostly range in the upper 50s to low 60s by late afternoon with pronounced boundary-layer mixing. Warmer mid-level temperatures and limited large-scale ascent across these regions should temper the overall intensity of any updrafts that can form and be sustained, and resultant intensity/coverage of this convection. Still, some guidance shows locally greater thunderstorm coverage and resulting isolated severe wind threat from the eastern TX Panhandle into far northwest OK and southern KS during the late afternoon/early evening, where low-level lapse rates should be maximized with robust daytime heating. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Sep 18 2024 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST NEBRASKA INTO FAR NORTHWEST IOWA...EASTERN SOUTH DAKOTA...AND WESTERN MINNESOTA... ...SUMMARY... Thunderstorms capable of producing severe wind gusts and large hail are possible today across parts of the eastern Dakotas and Minnesota into the mid Missouri Valley. A marginal severe threat will also extend southward into parts of the central and southern Plains. ...20Z Update... No changes were made to the ongoing forecast. For mesoscale details concerning eastern South Dakota and vicinity, see MCD 2083. Additional details can be found in the previous discussion below. ..Wendt.. 09/18/2024 .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Sep 18 2024/ ...Northern Plains/Upper Midwest to the Southern High Plains... A closed upper low centered over eastern MT will continue northeastward during the period, reaching southeast SK by early Thursday morning. Upper-level ridging extending northward from the northwest Gulf Coast into the upper MS Valley will slowly shift eastward to the Upper Great Lakes. A belt of enhanced southwesterly mid-level flow will extend from southern CA through the central High Plains, while also wrapping cyclonically through the eastern Dakotas and into southern Canada. At the surface, a trough/front extends southward from central ND into SD and western NE, before continuing southwestward over the central/southern High Plains. This boundary may serve as a focus for renewed thunderstorm development later today. A band of elevated convection has generally moved northward from northeast ND and northwest MN into southern MB. In the wake of this activity, cloud cover remains prevalent across much of the warm sector across the northern Plains/Upper Midwest. Still, filtered daytime heating of an adequately moist boundary layer should aid in the development of around 1500-2000 J/kg of MLCAPE by late afternoon. Isolated to scattered thunderstorms may form along/east of the surface trough/front within a favorable zone of 30-40 kt of effective bulk shear. But, better large-scale forcing associated with the upper low over the northern High Plains will tend to remain displaced north and west (in southern Canada). Accordingly, 12Z high-resolution guidance continues to vary regarding storm coverage across the Slight Risk (isolated versus scattered) given the weaker forcing aloft. Even with this continued uncertainty, various NAM/RAP forecast soundings still suggest a somewhat conditional risk for organized storms (mix of multicells and supercells). Severe hail/wind may accompany the stronger storms from late afternoon through early evening, before this activity eventually weakens. Further south into the central/southern Plains, low-levels are forecast to be somewhat drier near the surface trough, with surface dewpoints expected to mostly range in the upper 50s to low 60s by late afternoon with pronounced boundary-layer mixing. Warmer mid-level temperatures and limited large-scale ascent across these regions should temper the overall intensity of any updrafts that can form and be sustained, and resultant intensity/coverage of this convection. Still, some guidance shows locally greater thunderstorm coverage and resulting isolated severe wind threat from the eastern TX Panhandle into far northwest OK and southern KS during the late afternoon/early evening, where low-level lapse rates should be maximized with robust daytime heating. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Sep 18 2024 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST NEBRASKA INTO FAR NORTHWEST IOWA...EASTERN SOUTH DAKOTA...AND WESTERN MINNESOTA... ...SUMMARY... Thunderstorms capable of producing severe wind gusts and large hail are possible today across parts of the eastern Dakotas and Minnesota into the mid Missouri Valley. A marginal severe threat will also extend southward into parts of the central and southern Plains. ...20Z Update... No changes were made to the ongoing forecast. For mesoscale details concerning eastern South Dakota and vicinity, see MCD 2083. Additional details can be found in the previous discussion below. ..Wendt.. 09/18/2024 .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Sep 18 2024/ ...Northern Plains/Upper Midwest to the Southern High Plains... A closed upper low centered over eastern MT will continue northeastward during the period, reaching southeast SK by early Thursday morning. Upper-level ridging extending northward from the northwest Gulf Coast into the upper MS Valley will slowly shift eastward to the Upper Great Lakes. A belt of enhanced southwesterly mid-level flow will extend from southern CA through the central High Plains, while also wrapping cyclonically through the eastern Dakotas and into southern Canada. At the surface, a trough/front extends southward from central ND into SD and western NE, before continuing southwestward over the central/southern High Plains. This boundary may serve as a focus for renewed thunderstorm development later today. A band of elevated convection has generally moved northward from northeast ND and northwest MN into southern MB. In the wake of this activity, cloud cover remains prevalent across much of the warm sector across the northern Plains/Upper Midwest. Still, filtered daytime heating of an adequately moist boundary layer should aid in the development of around 1500-2000 J/kg of MLCAPE by late afternoon. Isolated to scattered thunderstorms may form along/east of the surface trough/front within a favorable zone of 30-40 kt of effective bulk shear. But, better large-scale forcing associated with the upper low over the northern High Plains will tend to remain displaced north and west (in southern Canada). Accordingly, 12Z high-resolution guidance continues to vary regarding storm coverage across the Slight Risk (isolated versus scattered) given the weaker forcing aloft. Even with this continued uncertainty, various NAM/RAP forecast soundings still suggest a somewhat conditional risk for organized storms (mix of multicells and supercells). Severe hail/wind may accompany the stronger storms from late afternoon through early evening, before this activity eventually weakens. Further south into the central/southern Plains, low-levels are forecast to be somewhat drier near the surface trough, with surface dewpoints expected to mostly range in the upper 50s to low 60s by late afternoon with pronounced boundary-layer mixing. Warmer mid-level temperatures and limited large-scale ascent across these regions should temper the overall intensity of any updrafts that can form and be sustained, and resultant intensity/coverage of this convection. Still, some guidance shows locally greater thunderstorm coverage and resulting isolated severe wind threat from the eastern TX Panhandle into far northwest OK and southern KS during the late afternoon/early evening, where low-level lapse rates should be maximized with robust daytime heating. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Sep 18 2024 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST NEBRASKA INTO FAR NORTHWEST IOWA...EASTERN SOUTH DAKOTA...AND WESTERN MINNESOTA... ...SUMMARY... Thunderstorms capable of producing severe wind gusts and large hail are possible today across parts of the eastern Dakotas and Minnesota into the mid Missouri Valley. A marginal severe threat will also extend southward into parts of the central and southern Plains. ...20Z Update... No changes were made to the ongoing forecast. For mesoscale details concerning eastern South Dakota and vicinity, see MCD 2083. Additional details can be found in the previous discussion below. ..Wendt.. 09/18/2024 .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Sep 18 2024/ ...Northern Plains/Upper Midwest to the Southern High Plains... A closed upper low centered over eastern MT will continue northeastward during the period, reaching southeast SK by early Thursday morning. Upper-level ridging extending northward from the northwest Gulf Coast into the upper MS Valley will slowly shift eastward to the Upper Great Lakes. A belt of enhanced southwesterly mid-level flow will extend from southern CA through the central High Plains, while also wrapping cyclonically through the eastern Dakotas and into southern Canada. At the surface, a trough/front extends southward from central ND into SD and western NE, before continuing southwestward over the central/southern High Plains. This boundary may serve as a focus for renewed thunderstorm development later today. A band of elevated convection has generally moved northward from northeast ND and northwest MN into southern MB. In the wake of this activity, cloud cover remains prevalent across much of the warm sector across the northern Plains/Upper Midwest. Still, filtered daytime heating of an adequately moist boundary layer should aid in the development of around 1500-2000 J/kg of MLCAPE by late afternoon. Isolated to scattered thunderstorms may form along/east of the surface trough/front within a favorable zone of 30-40 kt of effective bulk shear. But, better large-scale forcing associated with the upper low over the northern High Plains will tend to remain displaced north and west (in southern Canada). Accordingly, 12Z high-resolution guidance continues to vary regarding storm coverage across the Slight Risk (isolated versus scattered) given the weaker forcing aloft. Even with this continued uncertainty, various NAM/RAP forecast soundings still suggest a somewhat conditional risk for organized storms (mix of multicells and supercells). Severe hail/wind may accompany the stronger storms from late afternoon through early evening, before this activity eventually weakens. Further south into the central/southern Plains, low-levels are forecast to be somewhat drier near the surface trough, with surface dewpoints expected to mostly range in the upper 50s to low 60s by late afternoon with pronounced boundary-layer mixing. Warmer mid-level temperatures and limited large-scale ascent across these regions should temper the overall intensity of any updrafts that can form and be sustained, and resultant intensity/coverage of this convection. Still, some guidance shows locally greater thunderstorm coverage and resulting isolated severe wind threat from the eastern TX Panhandle into far northwest OK and southern KS during the late afternoon/early evening, where low-level lapse rates should be maximized with robust daytime heating. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Sep 18 2024 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST NEBRASKA INTO FAR NORTHWEST IOWA...EASTERN SOUTH DAKOTA...AND WESTERN MINNESOTA... ...SUMMARY... Thunderstorms capable of producing severe wind gusts and large hail are possible today across parts of the eastern Dakotas and Minnesota into the mid Missouri Valley. A marginal severe threat will also extend southward into parts of the central and southern Plains. ...20Z Update... No changes were made to the ongoing forecast. For mesoscale details concerning eastern South Dakota and vicinity, see MCD 2083. Additional details can be found in the previous discussion below. ..Wendt.. 09/18/2024 .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Sep 18 2024/ ...Northern Plains/Upper Midwest to the Southern High Plains... A closed upper low centered over eastern MT will continue northeastward during the period, reaching southeast SK by early Thursday morning. Upper-level ridging extending northward from the northwest Gulf Coast into the upper MS Valley will slowly shift eastward to the Upper Great Lakes. A belt of enhanced southwesterly mid-level flow will extend from southern CA through the central High Plains, while also wrapping cyclonically through the eastern Dakotas and into southern Canada. At the surface, a trough/front extends southward from central ND into SD and western NE, before continuing southwestward over the central/southern High Plains. This boundary may serve as a focus for renewed thunderstorm development later today. A band of elevated convection has generally moved northward from northeast ND and northwest MN into southern MB. In the wake of this activity, cloud cover remains prevalent across much of the warm sector across the northern Plains/Upper Midwest. Still, filtered daytime heating of an adequately moist boundary layer should aid in the development of around 1500-2000 J/kg of MLCAPE by late afternoon. Isolated to scattered thunderstorms may form along/east of the surface trough/front within a favorable zone of 30-40 kt of effective bulk shear. But, better large-scale forcing associated with the upper low over the northern High Plains will tend to remain displaced north and west (in southern Canada). Accordingly, 12Z high-resolution guidance continues to vary regarding storm coverage across the Slight Risk (isolated versus scattered) given the weaker forcing aloft. Even with this continued uncertainty, various NAM/RAP forecast soundings still suggest a somewhat conditional risk for organized storms (mix of multicells and supercells). Severe hail/wind may accompany the stronger storms from late afternoon through early evening, before this activity eventually weakens. Further south into the central/southern Plains, low-levels are forecast to be somewhat drier near the surface trough, with surface dewpoints expected to mostly range in the upper 50s to low 60s by late afternoon with pronounced boundary-layer mixing. Warmer mid-level temperatures and limited large-scale ascent across these regions should temper the overall intensity of any updrafts that can form and be sustained, and resultant intensity/coverage of this convection. Still, some guidance shows locally greater thunderstorm coverage and resulting isolated severe wind threat from the eastern TX Panhandle into far northwest OK and southern KS during the late afternoon/early evening, where low-level lapse rates should be maximized with robust daytime heating. Read more