Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Sat Mar 30 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Ohio Valley this afternoon/evening. Hail is the primary risk. ...Ohio Valley... Early-morning water-vapor imagery depicts a short-wave trough over IA. This feature is forecast to advance to near the IL/IN border by 12z, before progressing across the central Appalachians/middle Atlantic by early evening. West-southwesterly LLJ will be noted across the OH Valley early in the period, but this feature will translate downstream quickly in response to the aforementioned short wave. In its wake, weak height rises should occur across the OH Valley during peak heating. Scattered thunderstorms are currently ongoing across the Midwest from eastern IA into southern WI/northern IL. This activity is driven in large part by warm advection along the nose of the LLJ. As the LLJ shifts downstream this morning, greatest concentration of convection will spread across IN/OH. This early-day activity will evolve within an air mass not particularly bouyant, but within steep midlevel lapse rates. Of more concern will be the potential for afternoon convection, albeit more isolated in nature, that evolves due to strong boundary-layer heating. Short-range guidance suggests the strongest heating will occur ahead of a front, primarily south of I70, across IN/OH into portions of WV. While forcing will be weak after the passage of the short wave, forecast soundings suggest convective temperatures will be breached within a moistening air mass that could yield SBCAPE in excess of 1000 J/kg. Any storms that evolve within this air mass will do so within a strongly sheared environment. The potential for a few supercells exists, and hail would be a concern given the steep lapse rates. Lack of greater forcing favors isolated storm coverage. ..Darrow/Bentley.. 03/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Sat Mar 30 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Ohio Valley this afternoon/evening. Hail is the primary risk. ...Ohio Valley... Early-morning water-vapor imagery depicts a short-wave trough over IA. This feature is forecast to advance to near the IL/IN border by 12z, before progressing across the central Appalachians/middle Atlantic by early evening. West-southwesterly LLJ will be noted across the OH Valley early in the period, but this feature will translate downstream quickly in response to the aforementioned short wave. In its wake, weak height rises should occur across the OH Valley during peak heating. Scattered thunderstorms are currently ongoing across the Midwest from eastern IA into southern WI/northern IL. This activity is driven in large part by warm advection along the nose of the LLJ. As the LLJ shifts downstream this morning, greatest concentration of convection will spread across IN/OH. This early-day activity will evolve within an air mass not particularly bouyant, but within steep midlevel lapse rates. Of more concern will be the potential for afternoon convection, albeit more isolated in nature, that evolves due to strong boundary-layer heating. Short-range guidance suggests the strongest heating will occur ahead of a front, primarily south of I70, across IN/OH into portions of WV. While forcing will be weak after the passage of the short wave, forecast soundings suggest convective temperatures will be breached within a moistening air mass that could yield SBCAPE in excess of 1000 J/kg. Any storms that evolve within this air mass will do so within a strongly sheared environment. The potential for a few supercells exists, and hail would be a concern given the steep lapse rates. Lack of greater forcing favors isolated storm coverage. ..Darrow/Bentley.. 03/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Sat Mar 30 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Ohio Valley this afternoon/evening. Hail is the primary risk. ...Ohio Valley... Early-morning water-vapor imagery depicts a short-wave trough over IA. This feature is forecast to advance to near the IL/IN border by 12z, before progressing across the central Appalachians/middle Atlantic by early evening. West-southwesterly LLJ will be noted across the OH Valley early in the period, but this feature will translate downstream quickly in response to the aforementioned short wave. In its wake, weak height rises should occur across the OH Valley during peak heating. Scattered thunderstorms are currently ongoing across the Midwest from eastern IA into southern WI/northern IL. This activity is driven in large part by warm advection along the nose of the LLJ. As the LLJ shifts downstream this morning, greatest concentration of convection will spread across IN/OH. This early-day activity will evolve within an air mass not particularly bouyant, but within steep midlevel lapse rates. Of more concern will be the potential for afternoon convection, albeit more isolated in nature, that evolves due to strong boundary-layer heating. Short-range guidance suggests the strongest heating will occur ahead of a front, primarily south of I70, across IN/OH into portions of WV. While forcing will be weak after the passage of the short wave, forecast soundings suggest convective temperatures will be breached within a moistening air mass that could yield SBCAPE in excess of 1000 J/kg. Any storms that evolve within this air mass will do so within a strongly sheared environment. The potential for a few supercells exists, and hail would be a concern given the steep lapse rates. Lack of greater forcing favors isolated storm coverage. ..Darrow/Bentley.. 03/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Sat Mar 30 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Ohio Valley this afternoon/evening. Hail is the primary risk. ...Ohio Valley... Early-morning water-vapor imagery depicts a short-wave trough over IA. This feature is forecast to advance to near the IL/IN border by 12z, before progressing across the central Appalachians/middle Atlantic by early evening. West-southwesterly LLJ will be noted across the OH Valley early in the period, but this feature will translate downstream quickly in response to the aforementioned short wave. In its wake, weak height rises should occur across the OH Valley during peak heating. Scattered thunderstorms are currently ongoing across the Midwest from eastern IA into southern WI/northern IL. This activity is driven in large part by warm advection along the nose of the LLJ. As the LLJ shifts downstream this morning, greatest concentration of convection will spread across IN/OH. This early-day activity will evolve within an air mass not particularly bouyant, but within steep midlevel lapse rates. Of more concern will be the potential for afternoon convection, albeit more isolated in nature, that evolves due to strong boundary-layer heating. Short-range guidance suggests the strongest heating will occur ahead of a front, primarily south of I70, across IN/OH into portions of WV. While forcing will be weak after the passage of the short wave, forecast soundings suggest convective temperatures will be breached within a moistening air mass that could yield SBCAPE in excess of 1000 J/kg. Any storms that evolve within this air mass will do so within a strongly sheared environment. The potential for a few supercells exists, and hail would be a concern given the steep lapse rates. Lack of greater forcing favors isolated storm coverage. ..Darrow/Bentley.. 03/30/2024 Read more

MD 0312 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN IOWA AND NORTHERN ILLINOIS
Mesoscale Discussion 0312 NWS Storm Prediction Center Norman OK 0852 PM CDT Fri Mar 29 2024 Areas affected...eastern iowa and northern Illinois Concerning...Severe potential...Watch unlikely Valid 300152Z - 300315Z Probability of Watch Issuance...5 percent SUMMARY...A few strong thunderstorms are possible this evening with some hail possible. DISCUSSION...A few strong thunderstorms are possible this evening from eastern Iowa into northern Illinois. Instability was quite limited on the 00Z DVN RAOB. However, continued warm air advection has likely increased instability and moistened the column between 850 and 700mb over the past few hours. Therefore, despite the minimal instability, the moderate isentropic ascent associated with a ~40 knot low-level jet has proven sufficient for storms in the region. Given the strong unidirectional shear in the cloud-bearing layer, a few stronger storms with rotating updrafts are possible. Some hail to near 1 inch is possible, but expect the majority of hail to remain sub-severe. Isentropic ascent is expected to weaken in the next few hours as 850-700mb flow veers. This should bring an end to the marginal hail threat by late evening. ..Bentley/Goss.. 03/30/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...DVN...DMX... LAT...LON 41279313 41959246 42419107 42198898 41728788 40968764 40528833 40548968 40639156 40719245 40829282 41279313 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 PM CDT Fri Mar 29 2024 Valid 300100Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST... ...SUMMARY... Marginally severe hail remains possible tonight from eastern Iowa into northern Illinois. ...01z Update... Earlier thoughts regarding the prospect for a few robust storms across the Midwest remain. Moisture is gradually advancing north across the mid MS Valley per 50F surface dew points now north of I70 in MO. While 00z sounding from DVN exhibited very steep midlevel lapse rates, only 0.67 inch PW was observed on the sounding. Instability should increase over the next several hours such that elevated thunderstorms are expected to increase in areal coverage, initially over eastern IA. Latest radar/lightning data suggests isolated thunderstorms have recently developed over southeast IA and this activity will spread east within the warm advection zone into northern IL. Strongest updrafts may generate hail that could approach severe levels, most likely later this evening as buoyancy increases. Even so, these robust storms will remain isolated. ..Darrow.. 03/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 PM CDT Fri Mar 29 2024 Valid 300100Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST... ...SUMMARY... Marginally severe hail remains possible tonight from eastern Iowa into northern Illinois. ...01z Update... Earlier thoughts regarding the prospect for a few robust storms across the Midwest remain. Moisture is gradually advancing north across the mid MS Valley per 50F surface dew points now north of I70 in MO. While 00z sounding from DVN exhibited very steep midlevel lapse rates, only 0.67 inch PW was observed on the sounding. Instability should increase over the next several hours such that elevated thunderstorms are expected to increase in areal coverage, initially over eastern IA. Latest radar/lightning data suggests isolated thunderstorms have recently developed over southeast IA and this activity will spread east within the warm advection zone into northern IL. Strongest updrafts may generate hail that could approach severe levels, most likely later this evening as buoyancy increases. Even so, these robust storms will remain isolated. ..Darrow.. 03/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 PM CDT Fri Mar 29 2024 Valid 300100Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST... ...SUMMARY... Marginally severe hail remains possible tonight from eastern Iowa into northern Illinois. ...01z Update... Earlier thoughts regarding the prospect for a few robust storms across the Midwest remain. Moisture is gradually advancing north across the mid MS Valley per 50F surface dew points now north of I70 in MO. While 00z sounding from DVN exhibited very steep midlevel lapse rates, only 0.67 inch PW was observed on the sounding. Instability should increase over the next several hours such that elevated thunderstorms are expected to increase in areal coverage, initially over eastern IA. Latest radar/lightning data suggests isolated thunderstorms have recently developed over southeast IA and this activity will spread east within the warm advection zone into northern IL. Strongest updrafts may generate hail that could approach severe levels, most likely later this evening as buoyancy increases. Even so, these robust storms will remain isolated. ..Darrow.. 03/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 PM CDT Fri Mar 29 2024 Valid 300100Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST... ...SUMMARY... Marginally severe hail remains possible tonight from eastern Iowa into northern Illinois. ...01z Update... Earlier thoughts regarding the prospect for a few robust storms across the Midwest remain. Moisture is gradually advancing north across the mid MS Valley per 50F surface dew points now north of I70 in MO. While 00z sounding from DVN exhibited very steep midlevel lapse rates, only 0.67 inch PW was observed on the sounding. Instability should increase over the next several hours such that elevated thunderstorms are expected to increase in areal coverage, initially over eastern IA. Latest radar/lightning data suggests isolated thunderstorms have recently developed over southeast IA and this activity will spread east within the warm advection zone into northern IL. Strongest updrafts may generate hail that could approach severe levels, most likely later this evening as buoyancy increases. Even so, these robust storms will remain isolated. ..Darrow.. 03/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 PM CDT Fri Mar 29 2024 Valid 300100Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST... ...SUMMARY... Marginally severe hail remains possible tonight from eastern Iowa into northern Illinois. ...01z Update... Earlier thoughts regarding the prospect for a few robust storms across the Midwest remain. Moisture is gradually advancing north across the mid MS Valley per 50F surface dew points now north of I70 in MO. While 00z sounding from DVN exhibited very steep midlevel lapse rates, only 0.67 inch PW was observed on the sounding. Instability should increase over the next several hours such that elevated thunderstorms are expected to increase in areal coverage, initially over eastern IA. Latest radar/lightning data suggests isolated thunderstorms have recently developed over southeast IA and this activity will spread east within the warm advection zone into northern IL. Strongest updrafts may generate hail that could approach severe levels, most likely later this evening as buoyancy increases. Even so, these robust storms will remain isolated. ..Darrow.. 03/30/2024 Read more

No Mesoscale Discussions are in effect as of Fri Mar 29 23:51:02 UTC 2024.

No watches are valid as of Fri Mar 29 23:51:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0452 PM CDT Fri Mar 29 2024 Valid 311200Z - 061200Z ...Days 3-4/Sunday-Monday - Southern High Plains... Preceding a highly amplified western CONUS trough, a swath of strong deep-layer southwesterly flow will overspread the southern High Plains on Day 3/Sunday. At the same time, a lee cyclone will deepen over the central High Plains, with a dryline extending southward across west/central TX. A tightening pressure gradient, coupled with downslope-aided drying and mixing into the strong flow aloft, will yield widespread strong southwesterly surface winds and low RH across the southern High Plains (west of the dryline). Given antecedent drying of fine fuels across the region, an expansive area of critical fire-weather conditions is expected. On Day 4/Monday, the large-scale trough will continue eastward across the central/southern Plains, while a related Pacific cold front overspreads the region. While strong west-southwesterly flow along/behind the front and continued downslope drying will support elevated to locally critical fire-weather conditions across the southern High Plains, increasing cloud coverage and cooling surface temperatures limit confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. Thereafter, post-frontal conditions should temporarily limit fire-weather concerns across the central/southern Plains, though locally dry/breezy conditions are still possible -- especially along the Rio Grande on Day 5/Tuesday. The potential for critical conditions will return late in the extended forecast period ahead of the next large-scale trough over the West, though the details are unclear at this time. ..Weinman.. 03/29/2024 ...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 0452 PM CDT Fri Mar 29 2024 Valid 311200Z - 061200Z ...Days 3-4/Sunday-Monday - Southern High Plains... Preceding a highly amplified western CONUS trough, a swath of strong deep-layer southwesterly flow will overspread the southern High Plains on Day 3/Sunday. At the same time, a lee cyclone will deepen over the central High Plains, with a dryline extending southward across west/central TX. A tightening pressure gradient, coupled with downslope-aided drying and mixing into the strong flow aloft, will yield widespread strong southwesterly surface winds and low RH across the southern High Plains (west of the dryline). Given antecedent drying of fine fuels across the region, an expansive area of critical fire-weather conditions is expected. On Day 4/Monday, the large-scale trough will continue eastward across the central/southern Plains, while a related Pacific cold front overspreads the region. While strong west-southwesterly flow along/behind the front and continued downslope drying will support elevated to locally critical fire-weather conditions across the southern High Plains, increasing cloud coverage and cooling surface temperatures limit confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. Thereafter, post-frontal conditions should temporarily limit fire-weather concerns across the central/southern Plains, though locally dry/breezy conditions are still possible -- especially along the Rio Grande on Day 5/Tuesday. The potential for critical conditions will return late in the extended forecast period ahead of the next large-scale trough over the West, though the details are unclear at this time. ..Weinman.. 03/29/2024 ...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 0452 PM CDT Fri Mar 29 2024 Valid 311200Z - 061200Z ...Days 3-4/Sunday-Monday - Southern High Plains... Preceding a highly amplified western CONUS trough, a swath of strong deep-layer southwesterly flow will overspread the southern High Plains on Day 3/Sunday. At the same time, a lee cyclone will deepen over the central High Plains, with a dryline extending southward across west/central TX. A tightening pressure gradient, coupled with downslope-aided drying and mixing into the strong flow aloft, will yield widespread strong southwesterly surface winds and low RH across the southern High Plains (west of the dryline). Given antecedent drying of fine fuels across the region, an expansive area of critical fire-weather conditions is expected. On Day 4/Monday, the large-scale trough will continue eastward across the central/southern Plains, while a related Pacific cold front overspreads the region. While strong west-southwesterly flow along/behind the front and continued downslope drying will support elevated to locally critical fire-weather conditions across the southern High Plains, increasing cloud coverage and cooling surface temperatures limit confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. Thereafter, post-frontal conditions should temporarily limit fire-weather concerns across the central/southern Plains, though locally dry/breezy conditions are still possible -- especially along the Rio Grande on Day 5/Tuesday. The potential for critical conditions will return late in the extended forecast period ahead of the next large-scale trough over the West, though the details are unclear at this time. ..Weinman.. 03/29/2024 ...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 0452 PM CDT Fri Mar 29 2024 Valid 311200Z - 061200Z ...Days 3-4/Sunday-Monday - Southern High Plains... Preceding a highly amplified western CONUS trough, a swath of strong deep-layer southwesterly flow will overspread the southern High Plains on Day 3/Sunday. At the same time, a lee cyclone will deepen over the central High Plains, with a dryline extending southward across west/central TX. A tightening pressure gradient, coupled with downslope-aided drying and mixing into the strong flow aloft, will yield widespread strong southwesterly surface winds and low RH across the southern High Plains (west of the dryline). Given antecedent drying of fine fuels across the region, an expansive area of critical fire-weather conditions is expected. On Day 4/Monday, the large-scale trough will continue eastward across the central/southern Plains, while a related Pacific cold front overspreads the region. While strong west-southwesterly flow along/behind the front and continued downslope drying will support elevated to locally critical fire-weather conditions across the southern High Plains, increasing cloud coverage and cooling surface temperatures limit confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. Thereafter, post-frontal conditions should temporarily limit fire-weather concerns across the central/southern Plains, though locally dry/breezy conditions are still possible -- especially along the Rio Grande on Day 5/Tuesday. The potential for critical conditions will return late in the extended forecast period ahead of the next large-scale trough over the West, though the details are unclear at this time. ..Weinman.. 03/29/2024 ...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 0452 PM CDT Fri Mar 29 2024 Valid 311200Z - 061200Z ...Days 3-4/Sunday-Monday - Southern High Plains... Preceding a highly amplified western CONUS trough, a swath of strong deep-layer southwesterly flow will overspread the southern High Plains on Day 3/Sunday. At the same time, a lee cyclone will deepen over the central High Plains, with a dryline extending southward across west/central TX. A tightening pressure gradient, coupled with downslope-aided drying and mixing into the strong flow aloft, will yield widespread strong southwesterly surface winds and low RH across the southern High Plains (west of the dryline). Given antecedent drying of fine fuels across the region, an expansive area of critical fire-weather conditions is expected. On Day 4/Monday, the large-scale trough will continue eastward across the central/southern Plains, while a related Pacific cold front overspreads the region. While strong west-southwesterly flow along/behind the front and continued downslope drying will support elevated to locally critical fire-weather conditions across the southern High Plains, increasing cloud coverage and cooling surface temperatures limit confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. Thereafter, post-frontal conditions should temporarily limit fire-weather concerns across the central/southern Plains, though locally dry/breezy conditions are still possible -- especially along the Rio Grande on Day 5/Tuesday. The potential for critical conditions will return late in the extended forecast period ahead of the next large-scale trough over the West, though the details are unclear at this time. ..Weinman.. 03/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Fri Mar 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT FROM EASTERN IA INTO NORTHERN IL... ...SUMMARY... Marginally severe hail is possible tonight from eastern Iowa into northern Illinois. ...20Z Update... No changes have been made to the outlook. Isolated hail remains possible tonight from parts of eastern IA into northern IL, as elevated convection develops and spreads eastward. See the previous discussion below for more information. ..Dean.. 03/29/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Fri Mar 29 2024/ ...Synopsis... A deep midlevel low over the eastern Pacific will approach the central CA coast tonight, as an associated baroclinic zone spreads slowly eastward/inland this afternoon/evening. Weak buoyancy within the baroclinic zone could support some embedded convection with isolated lightning flashes. A downstream speed max over CO this morning will move toward the mid MS Valley overnight, and will help maintain lee cyclogenesis today across western KS and a weak/mobile cyclone into IA/IL tonight. ...Eastern IA/northern IL tonight... A modifying Gulf of Mexico air mass is returning northward into the southern Plains, to the east of the lee cyclone in western KS. Some increase in low-level moisture in a zone of low-level warm advection, beneath midlevel lapse rates near 7.5 C/km, will support elevated thunderstorm development early tonight over eastern IA and storms will subsequently spread eastward over northern IL (immediately in advance of the weak surface cyclone and ejecting midlevel speed max). MUCAPE near 1000 J/kg, relatively cool midlevel temperatures (near -18 C at 500 mb) and modest hodograph length/curvature may support some low-end/elevated supercells capable of producing isolated large hail of 1-1.5 inches in diameter before storm coverage increases and storm intensity decreases late tonight. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Fri Mar 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT FROM EASTERN IA INTO NORTHERN IL... ...SUMMARY... Marginally severe hail is possible tonight from eastern Iowa into northern Illinois. ...20Z Update... No changes have been made to the outlook. Isolated hail remains possible tonight from parts of eastern IA into northern IL, as elevated convection develops and spreads eastward. See the previous discussion below for more information. ..Dean.. 03/29/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Fri Mar 29 2024/ ...Synopsis... A deep midlevel low over the eastern Pacific will approach the central CA coast tonight, as an associated baroclinic zone spreads slowly eastward/inland this afternoon/evening. Weak buoyancy within the baroclinic zone could support some embedded convection with isolated lightning flashes. A downstream speed max over CO this morning will move toward the mid MS Valley overnight, and will help maintain lee cyclogenesis today across western KS and a weak/mobile cyclone into IA/IL tonight. ...Eastern IA/northern IL tonight... A modifying Gulf of Mexico air mass is returning northward into the southern Plains, to the east of the lee cyclone in western KS. Some increase in low-level moisture in a zone of low-level warm advection, beneath midlevel lapse rates near 7.5 C/km, will support elevated thunderstorm development early tonight over eastern IA and storms will subsequently spread eastward over northern IL (immediately in advance of the weak surface cyclone and ejecting midlevel speed max). MUCAPE near 1000 J/kg, relatively cool midlevel temperatures (near -18 C at 500 mb) and modest hodograph length/curvature may support some low-end/elevated supercells capable of producing isolated large hail of 1-1.5 inches in diameter before storm coverage increases and storm intensity decreases late tonight. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Fri Mar 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT FROM EASTERN IA INTO NORTHERN IL... ...SUMMARY... Marginally severe hail is possible tonight from eastern Iowa into northern Illinois. ...20Z Update... No changes have been made to the outlook. Isolated hail remains possible tonight from parts of eastern IA into northern IL, as elevated convection develops and spreads eastward. See the previous discussion below for more information. ..Dean.. 03/29/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Fri Mar 29 2024/ ...Synopsis... A deep midlevel low over the eastern Pacific will approach the central CA coast tonight, as an associated baroclinic zone spreads slowly eastward/inland this afternoon/evening. Weak buoyancy within the baroclinic zone could support some embedded convection with isolated lightning flashes. A downstream speed max over CO this morning will move toward the mid MS Valley overnight, and will help maintain lee cyclogenesis today across western KS and a weak/mobile cyclone into IA/IL tonight. ...Eastern IA/northern IL tonight... A modifying Gulf of Mexico air mass is returning northward into the southern Plains, to the east of the lee cyclone in western KS. Some increase in low-level moisture in a zone of low-level warm advection, beneath midlevel lapse rates near 7.5 C/km, will support elevated thunderstorm development early tonight over eastern IA and storms will subsequently spread eastward over northern IL (immediately in advance of the weak surface cyclone and ejecting midlevel speed max). MUCAPE near 1000 J/kg, relatively cool midlevel temperatures (near -18 C at 500 mb) and modest hodograph length/curvature may support some low-end/elevated supercells capable of producing isolated large hail of 1-1.5 inches in diameter before storm coverage increases and storm intensity decreases late tonight. Read more