Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in the southern High Plains. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a 50-65 kt 500-mb jetlet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across eastern NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms should be capable of producing at least isolated severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be curtailed by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential is evident on Saturday afternoon and evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. As such, a severe threat area has not yet been delineated but may be warranted in later outlooks if predictability increases. ..Grams.. 09/19/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in the southern High Plains. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a 50-65 kt 500-mb jetlet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across eastern NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms should be capable of producing at least isolated severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be curtailed by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential is evident on Saturday afternoon and evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. As such, a severe threat area has not yet been delineated but may be warranted in later outlooks if predictability increases. ..Grams.. 09/19/2024 Read more