Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Mar 18 2025 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN NEBRASKA THROUGH SOUTHWESTERN AND CENTRAL IOWA... ...SUMMARY... Isolated, marginally severe hail is possible by late tonight in a corridor from north central Kansas through central Iowa. ...Discussion... Much of the nation remains under the influence of one prominent belt of westerlies emanating from the northern mid-latitude Pacific. Within this regime, mid-level troughing is in the process of digging across the Intermountain West and Rockies. This includes one significant embedded smaller-scale perturbation approaching the southern Rockies, which is forecast to accelerate east-northeastward across the south central Great Plains by late tonight. Models indicate that this will be accompanied by a strong mid/upper jet streak, including a core intensifying in excess of 100 kt around 500 mb, nosing across the Texas Panhandle vicinity through the lower Missouri Valley from early this evening through 12Z Wednesday. It appears that this may be accompanied by substantive further deepening of a developing low across central through northeastern Kansas, within already deep surface troughing now present across the central/southern Great Plains into lower/middle Missouri Valley. In the wake of the prior cyclone which impacted much of the central and eastern U.S. and Gulf Basin late last week into the weekend, boundary-layer moistening across the western Gulf is underway, but still only supportive of rather modest low-level moistening across the Texas Gulf coast into southeastern Great Plains (including low to mid 50s F surface dew points). It appears that this will reach portions of the lower central Great Plains into Upper Midwest late this evening through early Wednesday. However, relatively warm and dry air in the lower/mid-troposphere, associated with a broad plume of elevated mixed-layer air overspreading the central/southern Great Plains and middle/lower Mississippi Valley, will tend to impede an appreciable risk for thunderstorm development. ...Central Great Plains toward the Upper Midwest... Perhaps as early as late this evening, into the overnight hours, model output continues to indicate that strengthening mid/upper forcing for ascent, coupled with better low-level moisture return, will overcome the inhibition and support a corridor of thunderstorm development. This likely will be focused within strengthening lower/mid-tropospheric warm advection, along a frontal zone extending to the east-northeast of the surface cyclone, across southeastern Nebraska through central Iowa by late tonight. Based at least on the latest NAM, it appears that the more sustained and stronger thunderstorm development may initiate as early as late evening near/east-northeast of the Concordia KS vicinity, before spreading northeastward. This seems likely to occur as convection begins to become increasingly rooted below the 700 mb level, closer to 850 mb, with soundings perhaps becoming characterized by "loaded gun" thermodynamic profiles above the near-surface stable layer. Although most unstable CAPE may mostly peak in the 500-750 J/kg range, stronger cells may become conducive to marginally severe hail, aided by strong shear in the convective layer. The potential for strong surface gusts is somewhat more uncertain. Although the risk for strong downdrafts to reach the surface appears negligible, gravity wave induced surface pressure perturbations supportive of gusty winds may not be entirely out of the question. ..Kerr/Bunting.. 03/18/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 AM CDT Tue Mar 18 2025 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE TONIGHT FROM EASTERN NE INTO IA... ...SUMMARY... Isolated, marginally severe hail is possible late tonight from eastern Nebraska across much of Iowa. ...Eastern NE/IA late tonight and early Wednesday... In advance of a pronounced midlevel shortwave trough over UT/northern AZ this morning, a surface lee cyclone will deepen across western KS and then move to far northwest MO by early Wednesday. Moisture return in the warm sector of this deepening cyclone will be limited by a prior frontal passage across the Gulf/northwest Caribbean, with only a narrow corridor of low-mid 50s boundary-layer dewpoints expected from eastern OK to far northwest MO. Though the warm sector will remain capped through the period, there could be sufficient ascent/moistening for elevated thunderstorm development by 06-12z from eastern NE across IA. Steep midlevel lapse rates and relatively cold midlevel temperatures will contribute to MUCAPE of 500-750 J/kg and the potential for isolated large hail (a few instances near 1 inch diameter) with elevated convection to the cool side of a baroclinic zone across eastern NE/IA. ..Thompson/Dean.. 03/18/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 AM CDT Tue Mar 18 2025 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE TONIGHT FROM EASTERN NE INTO IA... ...SUMMARY... Isolated, marginally severe hail is possible late tonight from eastern Nebraska across much of Iowa. ...Eastern NE/IA late tonight and early Wednesday... In advance of a pronounced midlevel shortwave trough over UT/northern AZ this morning, a surface lee cyclone will deepen across western KS and then move to far northwest MO by early Wednesday. Moisture return in the warm sector of this deepening cyclone will be limited by a prior frontal passage across the Gulf/northwest Caribbean, with only a narrow corridor of low-mid 50s boundary-layer dewpoints expected from eastern OK to far northwest MO. Though the warm sector will remain capped through the period, there could be sufficient ascent/moistening for elevated thunderstorm development by 06-12z from eastern NE across IA. Steep midlevel lapse rates and relatively cold midlevel temperatures will contribute to MUCAPE of 500-750 J/kg and the potential for isolated large hail (a few instances near 1 inch diameter) with elevated convection to the cool side of a baroclinic zone across eastern NE/IA. ..Thompson/Dean.. 03/18/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 AM CDT Tue Mar 18 2025 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE TONIGHT FROM EASTERN NE INTO IA... ...SUMMARY... Isolated, marginally severe hail is possible late tonight from eastern Nebraska across much of Iowa. ...Eastern NE/IA late tonight and early Wednesday... In advance of a pronounced midlevel shortwave trough over UT/northern AZ this morning, a surface lee cyclone will deepen across western KS and then move to far northwest MO by early Wednesday. Moisture return in the warm sector of this deepening cyclone will be limited by a prior frontal passage across the Gulf/northwest Caribbean, with only a narrow corridor of low-mid 50s boundary-layer dewpoints expected from eastern OK to far northwest MO. Though the warm sector will remain capped through the period, there could be sufficient ascent/moistening for elevated thunderstorm development by 06-12z from eastern NE across IA. Steep midlevel lapse rates and relatively cold midlevel temperatures will contribute to MUCAPE of 500-750 J/kg and the potential for isolated large hail (a few instances near 1 inch diameter) with elevated convection to the cool side of a baroclinic zone across eastern NE/IA. ..Thompson/Dean.. 03/18/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 AM CDT Tue Mar 18 2025 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE TONIGHT FROM EASTERN NE INTO IA... ...SUMMARY... Isolated, marginally severe hail is possible late tonight from eastern Nebraska across much of Iowa. ...Eastern NE/IA late tonight and early Wednesday... In advance of a pronounced midlevel shortwave trough over UT/northern AZ this morning, a surface lee cyclone will deepen across western KS and then move to far northwest MO by early Wednesday. Moisture return in the warm sector of this deepening cyclone will be limited by a prior frontal passage across the Gulf/northwest Caribbean, with only a narrow corridor of low-mid 50s boundary-layer dewpoints expected from eastern OK to far northwest MO. Though the warm sector will remain capped through the period, there could be sufficient ascent/moistening for elevated thunderstorm development by 06-12z from eastern NE across IA. Steep midlevel lapse rates and relatively cold midlevel temperatures will contribute to MUCAPE of 500-750 J/kg and the potential for isolated large hail (a few instances near 1 inch diameter) with elevated convection to the cool side of a baroclinic zone across eastern NE/IA. ..Thompson/Dean.. 03/18/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 AM CDT Tue Mar 18 2025 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE TONIGHT FROM EASTERN NE INTO IA... ...SUMMARY... Isolated, marginally severe hail is possible late tonight from eastern Nebraska across much of Iowa. ...Eastern NE/IA late tonight and early Wednesday... In advance of a pronounced midlevel shortwave trough over UT/northern AZ this morning, a surface lee cyclone will deepen across western KS and then move to far northwest MO by early Wednesday. Moisture return in the warm sector of this deepening cyclone will be limited by a prior frontal passage across the Gulf/northwest Caribbean, with only a narrow corridor of low-mid 50s boundary-layer dewpoints expected from eastern OK to far northwest MO. Though the warm sector will remain capped through the period, there could be sufficient ascent/moistening for elevated thunderstorm development by 06-12z from eastern NE across IA. Steep midlevel lapse rates and relatively cold midlevel temperatures will contribute to MUCAPE of 500-750 J/kg and the potential for isolated large hail (a few instances near 1 inch diameter) with elevated convection to the cool side of a baroclinic zone across eastern NE/IA. ..Thompson/Dean.. 03/18/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Tue Mar 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... ...Friday/Day 4 to Saturday/Day 5... On Friday and Saturday, a shortwave mid-level trough will move eastward from the Great Plains to the Eastern Seaboard, as a long fetch of west-northwest flow develops over much of the continental U.S. Isolated convection may develop ahead of the trough, but instability will likely be insufficient for a severe threat. In the wake of this system, low-level moisture return will begin along the western Gulf Coast. By Saturday, surface dewpoints are expected to be the upper 50s and lower 60s F over the Texas and Louisiana Coastal Plain. ...Sunday/Day 6 to Tuesday/Day 8.... On Sunday, moisture advection is forecast to increase over eastern parts of the southern Plains into the Ark-La-Tex. A mid-level trough is forecast to move across the central U.S. Ahead of the trough, moderate instability is forecast to develop across much of a moist airmass located from the southeastern third of Texas northeastward into the Ark-La-Tex. On Sunday, thunderstorms with a threat for isolated large hail and severe gusts are expected to develop along the northern edge of the moist sector, with a complex of storms moving southeastward across the Sabine and lower Mississippi Valleys overnight. On Monday and Tuesday, the mid-level trough is forecast to move into the eastern U.S., as a cold front advances southward to near the Gulf Coast. Although isolated storms could develop in the southern Gulf Coast states, limited large-scale ascent is expected to be problematic concerning an organized severe threat. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0207 AM CDT Tue Mar 18 2025 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm development will be possible on Thursday from parts of the Mid-Atlantic southward into eastern North Carolina. A severe threat is not expected. ...DISCUSSION... A pre-frontal trough will move from the Appalachians to the Atlantic Coastal plains on Thursday, as an associated mid-level trough moves through the Ohio and Tennessee Valleys. Low-topped convection is forecast to develop near the pre-frontal trough in the afternoon. Isolated thunderstorms will be possible along an axis of strong low-level flow from the Mid-Atlantic southward into eastern North Carolina, mainly during the mid to late afternoon. However, MUCAPE is forecast to remain below 200 J/kg along the instability axis, which should limit the severe potential. ..Broyles.. 03/18/2025 Read more