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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2024 Valid 132000Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST CO INTO SOUTHWEST NE AND FAR NORTHWEST KS... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening from northeast Colorado into southwest Nebraska and far northwest Kansas. Strong to isolated severe thunderstorms are also possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...20z Update... Adjustments were made to the Day 1 Outlook to remove portions of the Marginal Risk South Carolina behind an ongoing convective line and to introduce 2% tornado probabilities within the Slight Risk across northeast Colorado, southwest Nebraska, and northwest Kansas. Initial cellular development is ongoing across portions of Colorado and Wyoming this afternoon, with potential for strong to severe gusts and large hail. Through the afternoon/evening, evolution of a more organized convective line is expected across northeast Colorado. This line will propagate eastward into NE/KS through the evening. Lee cyclogenesis and mass response will support a strengthening low-level jet and resulting strengthening of low-level shear. The primary threat will be for damaging wind as this line continues eastward into the central Plains overnight. A Marginal Risk continues across the Intermountain West and Northern High Plains, where scattered thunderstorm development is ongoing. Strong to severe gusts and instances of severe hail will possible. ..Thornton/Mosier.. 08/13/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Aug 13 2024/ ...Central High Plains into the Central Plains... Low-amplitude shortwave trough currently moving through the Four Corners vicinity is expected to continue northeastward, helping to support afternoon thunderstorms across the central Rockies. Favorable low-level moisture will exist within the airmass downstream across the central High Plains, characterized by late afternoon dewpoints in the low to mid 60s. Ongoing cloud covered may delay heating a bit, but temperatures are still expected to reach the mid 80s by the late afternoon. These low-level thermodynamic conditions will help remove convective inhibition while also supporting moderate buoyancy. The westerly/southwesterly flow aloft should remain relatively modest (i.e. 20 to 30 kt at 500 mb), but the veering wind profiles expected to be in place will still result in moderate vertical shear. Current expectation is for 0-6 km bulk shear to range from 25 to 35 kt, with the highest values located over northeast CO into western NE. A predominantly multicellular mode is anticipated, with isolated large hail and a damaging gusts possible. The stronger shear over northeast CO suggests a more organized mode is possible here, with the development of a forward-propagating convective line anticipated. Strong gusts will be possible within this line. This line may continue eastward into the central Plains overnight, supported by a moderate low-level jet. ...Lower MO Valley into southeast NE... Ongoing convective complex moving through southwest MO is expected to continue southeastward while gradually weakening. Some re-development is possible during the evening, beginning across southwest MO, as warm-air advection occurs along the remnant outflow. Thunderstorm development should then expand northwestward into northeast KS, northwest MO, and southeast NE as the low-level jet continues to strengthen. Some isolated hail is possible within the strongest storms. Additionally, despite their elevated character, downdrafts could become strong enough to penetrate any low-level stability, with some damaging gusts possible. ...Intermountain West into the northern High Plains... Early-day satellite imagery shows upper ridging centered over the southern Plains and upper troughing from Pacific Northwest into central CA. Moderately enhanced southwesterly flow aloft is in place between these two features, from the Great Basin across much of the Intermountain West and into the northern High Plains. A shortwave trough currently moving through the western Great Basin is expected to progress through this southwesterly flow, reaching the northern High Plains by early Wednesday morning. Favorable moisture is in place ahead of this wave, as evidence by PWATs around 1" sampled by the 12Z soundings at SLC and GJT, with near 0.9" at BOI as well. Scattered to numerous thunderstorms are expected across the region, as northeastward-progressing shortwave trough interacts with this favorable moisture. Ongoing cloud cover and filtered daytime heating is expected to keep temperatures in the upper 70s across much of the region, with slightly warmer temperatures possible across eastern ID and northeastern UT. These temperatures combined with the mid-level moisture already in place will support moderate buoyancy, with the enhanced mid-level flow supporting moderate vertical shear as well. As a result, a largely multicellular mode is anticipated, but a few more organized storms are possible, with occasional bowing segments capable of producing strong gusts. The only exception is across the eastern ID/northeast UT vicinity, where slightly better buoyancy and shear could result in a few supercells. Anticipated isolated coverage currently precludes the need for higher severe probabilities. ...South Carolina... A weak surface low is near the southern SC coast this morning. Modest low-level convergence from this low northwestward into western SC/northeast GA is helping support showers and occasional thunderstorms. This convergence will likely persist throughout the day, with the showers and thunderstorms progressing gradually eastward. A very moist airmass is in place, as evidenced by 16.7 g/kg lowest 100-mb mean mixing ratio on the 12Z CHS sounding, and will diurnally destabilize today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2024 Valid 132000Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST CO INTO SOUTHWEST NE AND FAR NORTHWEST KS... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening from northeast Colorado into southwest Nebraska and far northwest Kansas. Strong to isolated severe thunderstorms are also possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...20z Update... Adjustments were made to the Day 1 Outlook to remove portions of the Marginal Risk South Carolina behind an ongoing convective line and to introduce 2% tornado probabilities within the Slight Risk across northeast Colorado, southwest Nebraska, and northwest Kansas. Initial cellular development is ongoing across portions of Colorado and Wyoming this afternoon, with potential for strong to severe gusts and large hail. Through the afternoon/evening, evolution of a more organized convective line is expected across northeast Colorado. This line will propagate eastward into NE/KS through the evening. Lee cyclogenesis and mass response will support a strengthening low-level jet and resulting strengthening of low-level shear. The primary threat will be for damaging wind as this line continues eastward into the central Plains overnight. A Marginal Risk continues across the Intermountain West and Northern High Plains, where scattered thunderstorm development is ongoing. Strong to severe gusts and instances of severe hail will possible. ..Thornton/Mosier.. 08/13/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Aug 13 2024/ ...Central High Plains into the Central Plains... Low-amplitude shortwave trough currently moving through the Four Corners vicinity is expected to continue northeastward, helping to support afternoon thunderstorms across the central Rockies. Favorable low-level moisture will exist within the airmass downstream across the central High Plains, characterized by late afternoon dewpoints in the low to mid 60s. Ongoing cloud covered may delay heating a bit, but temperatures are still expected to reach the mid 80s by the late afternoon. These low-level thermodynamic conditions will help remove convective inhibition while also supporting moderate buoyancy. The westerly/southwesterly flow aloft should remain relatively modest (i.e. 20 to 30 kt at 500 mb), but the veering wind profiles expected to be in place will still result in moderate vertical shear. Current expectation is for 0-6 km bulk shear to range from 25 to 35 kt, with the highest values located over northeast CO into western NE. A predominantly multicellular mode is anticipated, with isolated large hail and a damaging gusts possible. The stronger shear over northeast CO suggests a more organized mode is possible here, with the development of a forward-propagating convective line anticipated. Strong gusts will be possible within this line. This line may continue eastward into the central Plains overnight, supported by a moderate low-level jet. ...Lower MO Valley into southeast NE... Ongoing convective complex moving through southwest MO is expected to continue southeastward while gradually weakening. Some re-development is possible during the evening, beginning across southwest MO, as warm-air advection occurs along the remnant outflow. Thunderstorm development should then expand northwestward into northeast KS, northwest MO, and southeast NE as the low-level jet continues to strengthen. Some isolated hail is possible within the strongest storms. Additionally, despite their elevated character, downdrafts could become strong enough to penetrate any low-level stability, with some damaging gusts possible. ...Intermountain West into the northern High Plains... Early-day satellite imagery shows upper ridging centered over the southern Plains and upper troughing from Pacific Northwest into central CA. Moderately enhanced southwesterly flow aloft is in place between these two features, from the Great Basin across much of the Intermountain West and into the northern High Plains. A shortwave trough currently moving through the western Great Basin is expected to progress through this southwesterly flow, reaching the northern High Plains by early Wednesday morning. Favorable moisture is in place ahead of this wave, as evidence by PWATs around 1" sampled by the 12Z soundings at SLC and GJT, with near 0.9" at BOI as well. Scattered to numerous thunderstorms are expected across the region, as northeastward-progressing shortwave trough interacts with this favorable moisture. Ongoing cloud cover and filtered daytime heating is expected to keep temperatures in the upper 70s across much of the region, with slightly warmer temperatures possible across eastern ID and northeastern UT. These temperatures combined with the mid-level moisture already in place will support moderate buoyancy, with the enhanced mid-level flow supporting moderate vertical shear as well. As a result, a largely multicellular mode is anticipated, but a few more organized storms are possible, with occasional bowing segments capable of producing strong gusts. The only exception is across the eastern ID/northeast UT vicinity, where slightly better buoyancy and shear could result in a few supercells. Anticipated isolated coverage currently precludes the need for higher severe probabilities. ...South Carolina... A weak surface low is near the southern SC coast this morning. Modest low-level convergence from this low northwestward into western SC/northeast GA is helping support showers and occasional thunderstorms. This convergence will likely persist throughout the day, with the showers and thunderstorms progressing gradually eastward. A very moist airmass is in place, as evidenced by 16.7 g/kg lowest 100-mb mean mixing ratio on the 12Z CHS sounding, and will diurnally destabilize today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. Read more

MD 1891 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHERN SOUTH CAROLINA
Mesoscale Discussion 1891 NWS Storm Prediction Center Norman OK 1253 PM CDT Tue Aug 13 2024 Areas affected...parts of southern South Carolina Concerning...Severe potential...Watch unlikely Valid 131753Z - 132030Z Probability of Watch Issuance...20 percent SUMMARY...A growing and gradually organizing cluster of storms may pose increasing risk for potentially damaging wind gusts across the South Carolina Lowcountry through 4-6 PM EDT. DISCUSSION...Thunderstorms have recently begun to intensify in a small cluster along a strengthening surface cold pool now south of the Columbia area. This is occurring beneath modest (including around 30 kt near 500 mb) west-northwesterly mid/upper flow, and along a weak south-southwestward advancing front to the lee of the southern Appalachians. The frontal zone extends eastward into coastal areas northeast of Charleston, and is forecast to slowly approach the Savannah area through late afternoon. Although forecast soundings across this region exhibit notable relative warmth, and weak lapse rates, within a layer roughly from 700-500 mb, seasonably high boundary-layer moisture content (including lower/mid 70s F dew points) along the front appears to be contributing to sizable mixed-layer CAPE on the order of 2000+ J/kg with insolation. As modest low-level inflow and lift along the strengthening surface cold pool continue to overcome the inhibition, further upscale convective growth appears possible across the Lowcountry vicinity of South Carolina through 20-22Z. Gradually, this may be accompanied by strengthening rear inflow and potential for strong to severe surface gusts, despite the weak low-level ambient wind fields. ..Kerr/Mosier.. 08/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...CAE... LAT...LON 33598124 33488060 33037966 32538008 32318073 32888151 33418229 33778204 33598124 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more