Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0319 PM CDT Wed Sep 18 2019 Valid 182000Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHERN WISCONSIN... ...SUMMARY... A few strong storms are possible this evening from northern and central Wisconsin into southeast Minnesota. ...DISCUSSION... The only change to the outlook is to remove thunder from parts of western and northern Minnesota where dry air advection is reducing instability and reducing the chance for thunderstorm development. ..Broyles.. 09/18/2019 .PREV DISCUSSION... /ISSUED 1116 AM CDT Wed Sep 18 2019/ ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0319 PM CDT Wed Sep 18 2019 Valid 182000Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHERN WISCONSIN... ...SUMMARY... A few strong storms are possible this evening from northern and central Wisconsin into southeast Minnesota. ...DISCUSSION... The only change to the outlook is to remove thunder from parts of western and northern Minnesota where dry air advection is reducing instability and reducing the chance for thunderstorm development. ..Broyles.. 09/18/2019 .PREV DISCUSSION... /ISSUED 1116 AM CDT Wed Sep 18 2019/ ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0319 PM CDT Wed Sep 18 2019 Valid 182000Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHERN WISCONSIN... ...SUMMARY... A few strong storms are possible this evening from northern and central Wisconsin into southeast Minnesota. ...DISCUSSION... The only change to the outlook is to remove thunder from parts of western and northern Minnesota where dry air advection is reducing instability and reducing the chance for thunderstorm development. ..Broyles.. 09/18/2019 .PREV DISCUSSION... /ISSUED 1116 AM CDT Wed Sep 18 2019/ ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. Read more

No Mesoscale Discussions are in effect as of Wed Sep 18 20:24:04 UTC 2019.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0134 PM CDT Wed Sep 18 2019 Valid 191200Z - 201200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWEST ARIZONA AND SOUTHERN/CENTRAL UTAH... ...Southern Great Basin into the Central Rockies... Recent guidance suggests minimum RH values at or below 15 percent may occur a bit farther north and the critical delineation has been adjusted accordingly. Otherwise, the overall forecast remains on track with sustained winds from 30-35 mph (gusts to 45 mph) expected amidst afternoon RH values around 10-15 percent across northwest AZ and southern/central UT. Similar winds and slightly lower RH values are anticipated farther north across northwest UT and southern/central WY. ..Mosier.. 09/18/2019 .PREV DISCUSSION... /ISSUED 0130 AM CDT Wed Sep 18 2019/ ...Synopsis... A strong mid-level jet streak will traverse the base of the mid-level trough in the western CONUS on Thursday and overspread dry portions of the southwest and Great Basin. This stronger mid-level flow is expected to mix to the surface with wind speeds as high as 30 to 35 mph in northern Arizona and southwest Utah. In addition, relative humidity in this area is forecast to be in the 10 to 20 percent range. 20 to 30 mph surface winds are expected ahead of the surface front in northern Utah and into southern Wyoming as well, but relative humidity farther north is expected to be 20 to 25 percent. Therefore, an elevated delineation has been added across this region with a critical delineation in southern Utah and northwest Arizona where relative humidity is expected to be lower and surface winds are expected to be higher. ...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 0134 PM CDT Wed Sep 18 2019 Valid 191200Z - 201200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWEST ARIZONA AND SOUTHERN/CENTRAL UTAH... ...Southern Great Basin into the Central Rockies... Recent guidance suggests minimum RH values at or below 15 percent may occur a bit farther north and the critical delineation has been adjusted accordingly. Otherwise, the overall forecast remains on track with sustained winds from 30-35 mph (gusts to 45 mph) expected amidst afternoon RH values around 10-15 percent across northwest AZ and southern/central UT. Similar winds and slightly lower RH values are anticipated farther north across northwest UT and southern/central WY. ..Mosier.. 09/18/2019 .PREV DISCUSSION... /ISSUED 0130 AM CDT Wed Sep 18 2019/ ...Synopsis... A strong mid-level jet streak will traverse the base of the mid-level trough in the western CONUS on Thursday and overspread dry portions of the southwest and Great Basin. This stronger mid-level flow is expected to mix to the surface with wind speeds as high as 30 to 35 mph in northern Arizona and southwest Utah. In addition, relative humidity in this area is forecast to be in the 10 to 20 percent range. 20 to 30 mph surface winds are expected ahead of the surface front in northern Utah and into southern Wyoming as well, but relative humidity farther north is expected to be 20 to 25 percent. Therefore, an elevated delineation has been added across this region with a critical delineation in southern Utah and northwest Arizona where relative humidity is expected to be lower and surface winds are expected to be higher. ...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 0134 PM CDT Wed Sep 18 2019 Valid 191200Z - 201200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWEST ARIZONA AND SOUTHERN/CENTRAL UTAH... ...Southern Great Basin into the Central Rockies... Recent guidance suggests minimum RH values at or below 15 percent may occur a bit farther north and the critical delineation has been adjusted accordingly. Otherwise, the overall forecast remains on track with sustained winds from 30-35 mph (gusts to 45 mph) expected amidst afternoon RH values around 10-15 percent across northwest AZ and southern/central UT. Similar winds and slightly lower RH values are anticipated farther north across northwest UT and southern/central WY. ..Mosier.. 09/18/2019 .PREV DISCUSSION... /ISSUED 0130 AM CDT Wed Sep 18 2019/ ...Synopsis... A strong mid-level jet streak will traverse the base of the mid-level trough in the western CONUS on Thursday and overspread dry portions of the southwest and Great Basin. This stronger mid-level flow is expected to mix to the surface with wind speeds as high as 30 to 35 mph in northern Arizona and southwest Utah. In addition, relative humidity in this area is forecast to be in the 10 to 20 percent range. 20 to 30 mph surface winds are expected ahead of the surface front in northern Utah and into southern Wyoming as well, but relative humidity farther north is expected to be 20 to 25 percent. Therefore, an elevated delineation has been added across this region with a critical delineation in southern Utah and northwest Arizona where relative humidity is expected to be lower and surface winds are expected to be higher. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Wed Sep 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN PLAINS... ...SUMMARY... Isolated thunderstorms capable of hail and marginally severe wind gusts will be possible in parts of the northern Plains from Thursday evening into the overnight period. ...Northern Plains... An upper-level trough will move eastward across the Intermountain West on Thursday as south-southwesterly mid-level flow remains over the Rockies and High Plains. At the surface, a low is forecast to develop in the northern High Plains helping to reinforce southeasterly flow across the Dakotas. This will result in strengthening low-level moisture advection across the northern Plains on Thursday as a low-level jet develops across the central and northern Plains. In response to lift associated with the jet, isolated thunderstorms will be possible Thursday evening into the overnight period across western South Dakota, eastern Montana and western to central North Dakota. Although GFS and NAM forecast soundings across the northern Plains in the 03Z to 06Z/Friday show a low-level temperature inversion, MUCAPE values could reach as high as 3000 to 4500 J/kg. This combined with effective shear of 30 to 40 kt should be enough for a hail threat with the stronger updrafts. In spite of the temperature inversion, a few strong wind gusts can not be ruled out if a supercell can organize in the most favorable environment. The marginal severe threat could continue through the end of the period due to the low-level jet which is forecast to strengthen through much of the night. ...East Texas... The remnants of Imelda is forecast to move slowly across parts of east Texas on Thursday. The National Hurricane Center is forecasting very heavy rainfall to be associated with the system. Although a strong wind gust can not be ruled out within the stronger convection, the threat is not expected to meet the 5 percent wind criteria needed for an outlook area. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: 5% - Marginal ..Broyles.. 09/18/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Wed Sep 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN PLAINS... ...SUMMARY... Isolated thunderstorms capable of hail and marginally severe wind gusts will be possible in parts of the northern Plains from Thursday evening into the overnight period. ...Northern Plains... An upper-level trough will move eastward across the Intermountain West on Thursday as south-southwesterly mid-level flow remains over the Rockies and High Plains. At the surface, a low is forecast to develop in the northern High Plains helping to reinforce southeasterly flow across the Dakotas. This will result in strengthening low-level moisture advection across the northern Plains on Thursday as a low-level jet develops across the central and northern Plains. In response to lift associated with the jet, isolated thunderstorms will be possible Thursday evening into the overnight period across western South Dakota, eastern Montana and western to central North Dakota. Although GFS and NAM forecast soundings across the northern Plains in the 03Z to 06Z/Friday show a low-level temperature inversion, MUCAPE values could reach as high as 3000 to 4500 J/kg. This combined with effective shear of 30 to 40 kt should be enough for a hail threat with the stronger updrafts. In spite of the temperature inversion, a few strong wind gusts can not be ruled out if a supercell can organize in the most favorable environment. The marginal severe threat could continue through the end of the period due to the low-level jet which is forecast to strengthen through much of the night. ...East Texas... The remnants of Imelda is forecast to move slowly across parts of east Texas on Thursday. The National Hurricane Center is forecasting very heavy rainfall to be associated with the system. Although a strong wind gust can not be ruled out within the stronger convection, the threat is not expected to meet the 5 percent wind criteria needed for an outlook area. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: 5% - Marginal ..Broyles.. 09/18/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Wed Sep 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN PLAINS... ...SUMMARY... Isolated thunderstorms capable of hail and marginally severe wind gusts will be possible in parts of the northern Plains from Thursday evening into the overnight period. ...Northern Plains... An upper-level trough will move eastward across the Intermountain West on Thursday as south-southwesterly mid-level flow remains over the Rockies and High Plains. At the surface, a low is forecast to develop in the northern High Plains helping to reinforce southeasterly flow across the Dakotas. This will result in strengthening low-level moisture advection across the northern Plains on Thursday as a low-level jet develops across the central and northern Plains. In response to lift associated with the jet, isolated thunderstorms will be possible Thursday evening into the overnight period across western South Dakota, eastern Montana and western to central North Dakota. Although GFS and NAM forecast soundings across the northern Plains in the 03Z to 06Z/Friday show a low-level temperature inversion, MUCAPE values could reach as high as 3000 to 4500 J/kg. This combined with effective shear of 30 to 40 kt should be enough for a hail threat with the stronger updrafts. In spite of the temperature inversion, a few strong wind gusts can not be ruled out if a supercell can organize in the most favorable environment. The marginal severe threat could continue through the end of the period due to the low-level jet which is forecast to strengthen through much of the night. ...East Texas... The remnants of Imelda is forecast to move slowly across parts of east Texas on Thursday. The National Hurricane Center is forecasting very heavy rainfall to be associated with the system. Although a strong wind gust can not be ruled out within the stronger convection, the threat is not expected to meet the 5 percent wind criteria needed for an outlook area. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: 5% - Marginal ..Broyles.. 09/18/2019 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1139 AM CDT Wed Sep 18 2019 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR FOR PORTIONS OF THE SOUTHERN GREAT BASIN... ...Southern Great Basin into the Central Rockies... Afternoon RH values are still expected to drop below 15 percent for much of southern NV, southwest UT, and far northwest AZ. Sustained winds from 20 to 25 mph with gusts to 35 mph are also possible. These meteorological conditions combined with dry fuels support critical fire weather conditions and no change is needed to the areas delineated in the previous forecast. Elevated fire weather conditions will extend across the remainder of UT into far southeast ID, southwest WY, and far northwest CO. In these areas, sustained winds are expected to be 15 to 20 mph) with afternoon RH around 15 to 20 percent. ..Mosier.. 09/18/2019 .PREV DISCUSSION... /ISSUED 0129 AM CDT Wed Sep 18 2019/ ...Synopsis... A mid-level trough will amplify across the western CONUS today. This will lead to strengthening southwesterly mid-level flow by this afternoon/evening across much of the Great Basin. At the surface, a cold front will be moving southeastward across the Great Basin. Ahead of this front, stronger mid-level flow is expected to mix toward the surface with winds of 20 to 25 mph and relative humidity around 10 to 15 percent. Elevated fire weather conditions are expected to extend into eastern Idaho and portions of Wyoming where RH should be around 15 to 20 percent and winds should be 15 to 20 mph. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1139 AM CDT Wed Sep 18 2019 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR FOR PORTIONS OF THE SOUTHERN GREAT BASIN... ...Southern Great Basin into the Central Rockies... Afternoon RH values are still expected to drop below 15 percent for much of southern NV, southwest UT, and far northwest AZ. Sustained winds from 20 to 25 mph with gusts to 35 mph are also possible. These meteorological conditions combined with dry fuels support critical fire weather conditions and no change is needed to the areas delineated in the previous forecast. Elevated fire weather conditions will extend across the remainder of UT into far southeast ID, southwest WY, and far northwest CO. In these areas, sustained winds are expected to be 15 to 20 mph) with afternoon RH around 15 to 20 percent. ..Mosier.. 09/18/2019 .PREV DISCUSSION... /ISSUED 0129 AM CDT Wed Sep 18 2019/ ...Synopsis... A mid-level trough will amplify across the western CONUS today. This will lead to strengthening southwesterly mid-level flow by this afternoon/evening across much of the Great Basin. At the surface, a cold front will be moving southeastward across the Great Basin. Ahead of this front, stronger mid-level flow is expected to mix toward the surface with winds of 20 to 25 mph and relative humidity around 10 to 15 percent. Elevated fire weather conditions are expected to extend into eastern Idaho and portions of Wyoming where RH should be around 15 to 20 percent and winds should be 15 to 20 mph. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1139 AM CDT Wed Sep 18 2019 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR FOR PORTIONS OF THE SOUTHERN GREAT BASIN... ...Southern Great Basin into the Central Rockies... Afternoon RH values are still expected to drop below 15 percent for much of southern NV, southwest UT, and far northwest AZ. Sustained winds from 20 to 25 mph with gusts to 35 mph are also possible. These meteorological conditions combined with dry fuels support critical fire weather conditions and no change is needed to the areas delineated in the previous forecast. Elevated fire weather conditions will extend across the remainder of UT into far southeast ID, southwest WY, and far northwest CO. In these areas, sustained winds are expected to be 15 to 20 mph) with afternoon RH around 15 to 20 percent. ..Mosier.. 09/18/2019 .PREV DISCUSSION... /ISSUED 0129 AM CDT Wed Sep 18 2019/ ...Synopsis... A mid-level trough will amplify across the western CONUS today. This will lead to strengthening southwesterly mid-level flow by this afternoon/evening across much of the Great Basin. At the surface, a cold front will be moving southeastward across the Great Basin. Ahead of this front, stronger mid-level flow is expected to mix toward the surface with winds of 20 to 25 mph and relative humidity around 10 to 15 percent. Elevated fire weather conditions are expected to extend into eastern Idaho and portions of Wyoming where RH should be around 15 to 20 percent and winds should be 15 to 20 mph. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Wed Sep 18 2019 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING OVER PORTIONS OF WESTERN WISCONSIN AND SOUTHEAST MINNESOTA... ...SUMMARY... A few strong storms are possible this evening from western Wisconsin into southeast Minnesota. ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. ..Hart/Smith.. 09/18/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Wed Sep 18 2019 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING OVER PORTIONS OF WESTERN WISCONSIN AND SOUTHEAST MINNESOTA... ...SUMMARY... A few strong storms are possible this evening from western Wisconsin into southeast Minnesota. ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. ..Hart/Smith.. 09/18/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Wed Sep 18 2019 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING OVER PORTIONS OF WESTERN WISCONSIN AND SOUTHEAST MINNESOTA... ...SUMMARY... A few strong storms are possible this evening from western Wisconsin into southeast Minnesota. ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. ..Hart/Smith.. 09/18/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Wed Sep 18 2019 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING OVER PORTIONS OF WESTERN WISCONSIN AND SOUTHEAST MINNESOTA... ...SUMMARY... A few strong storms are possible this evening from western Wisconsin into southeast Minnesota. ...WI/MN... A strong negatively-tilted shortwave trough is rotating northeastward across ND into northern MN. A trailing cold front extends across MN into northwest IA. Clouds are prevalent along the front, but should slowly dissipate by mid afternoon, allowing some heating/destabilization to occur. This is expected to result in scattered thunderstorm development near the MN/WI border - mainly after 00z. Forecast soundings suggest sufficient winds aloft and CAPE to promote a few gusty/damaging wind reports, but organized severe activity is not anticipated. ...TX/LA... A broad precipitation shield continues with Imelda, with the only areas of more discrete convective elements along the far eastern and southern peripheries of the complex. Local VAD profiles show that low-level shear is not particularly strong in these outer bands. While transient rotation is possible in the strongest cores, the tornado threat appears to remain low. ..Hart/Smith.. 09/18/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Wed Sep 18 2019 Valid 181300Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Weakly rotating storms may occur near the southeast Texas/southwest Louisiana border today, and a few strong storms are possible this morning and again tonight from western Wisconsin to Iowa and eastern Nebraska. However, the threat for severe storms appears too low for any outlook areas. ...WI/MN to eastern NE through tonight... A compact shortwave trough over ND will eject east-northeastward across northwest MN to ON by this evening, as an associated surface cold front moves eastward across MN, but stalls across eastern NE. A broad zone of mainly elevated convection is ongoing this morning from northern IA into eastern MN in conjunction with low-level warm advection. The low-level jet will develop northeastward toward ON by this afternoon, with weakening flow and forcing for ascent farther south contributing to weakening of the convection through the day. Additional thunderstorms may form along the stalling front this evening into tonight from northwest WI across IA to eastern NE, though relatively weak deep-layer vertical shear suggests that organized severe storms are unlikely. ...Extreme upper TX/southwest LA coasts today... The remnant center of tropical depression Imelda continues to drift generally northward to the northwest of Houston. The primary confluence band has established near the coast to the south of the cyclone center. Earlier this morning, some mass response was apparent due to latent heat release with 30 kt low-level southerly flow just offshore, and a few rotating storms were noted just off the upper TX coast. However, the convection has developed a bit of a cold pool and more linear structure, and the 12z sounding from LCH immediately east of the main band shows limited potential for rotating storms, at best. While a brief/weak tornado cannot be completely ruled out, the overall threat appears too marginal to warrant the addition of an outlook area. ...Elsewhere... A few low-topped thunderstorms can be expected near the Pacific Northwest coast this morning, and spread inland during the day with the midlevel trough and steeper lapse rates. A few thunderstorms are also expected with a backdoor cold front that will move southwestward across GA/FL. ..Thompson/Kerr.. 09/18/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Wed Sep 18 2019 Valid 181300Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Weakly rotating storms may occur near the southeast Texas/southwest Louisiana border today, and a few strong storms are possible this morning and again tonight from western Wisconsin to Iowa and eastern Nebraska. However, the threat for severe storms appears too low for any outlook areas. ...WI/MN to eastern NE through tonight... A compact shortwave trough over ND will eject east-northeastward across northwest MN to ON by this evening, as an associated surface cold front moves eastward across MN, but stalls across eastern NE. A broad zone of mainly elevated convection is ongoing this morning from northern IA into eastern MN in conjunction with low-level warm advection. The low-level jet will develop northeastward toward ON by this afternoon, with weakening flow and forcing for ascent farther south contributing to weakening of the convection through the day. Additional thunderstorms may form along the stalling front this evening into tonight from northwest WI across IA to eastern NE, though relatively weak deep-layer vertical shear suggests that organized severe storms are unlikely. ...Extreme upper TX/southwest LA coasts today... The remnant center of tropical depression Imelda continues to drift generally northward to the northwest of Houston. The primary confluence band has established near the coast to the south of the cyclone center. Earlier this morning, some mass response was apparent due to latent heat release with 30 kt low-level southerly flow just offshore, and a few rotating storms were noted just off the upper TX coast. However, the convection has developed a bit of a cold pool and more linear structure, and the 12z sounding from LCH immediately east of the main band shows limited potential for rotating storms, at best. While a brief/weak tornado cannot be completely ruled out, the overall threat appears too marginal to warrant the addition of an outlook area. ...Elsewhere... A few low-topped thunderstorms can be expected near the Pacific Northwest coast this morning, and spread inland during the day with the midlevel trough and steeper lapse rates. A few thunderstorms are also expected with a backdoor cold front that will move southwestward across GA/FL. ..Thompson/Kerr.. 09/18/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Wed Sep 18 2019 Valid 181300Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Weakly rotating storms may occur near the southeast Texas/southwest Louisiana border today, and a few strong storms are possible this morning and again tonight from western Wisconsin to Iowa and eastern Nebraska. However, the threat for severe storms appears too low for any outlook areas. ...WI/MN to eastern NE through tonight... A compact shortwave trough over ND will eject east-northeastward across northwest MN to ON by this evening, as an associated surface cold front moves eastward across MN, but stalls across eastern NE. A broad zone of mainly elevated convection is ongoing this morning from northern IA into eastern MN in conjunction with low-level warm advection. The low-level jet will develop northeastward toward ON by this afternoon, with weakening flow and forcing for ascent farther south contributing to weakening of the convection through the day. Additional thunderstorms may form along the stalling front this evening into tonight from northwest WI across IA to eastern NE, though relatively weak deep-layer vertical shear suggests that organized severe storms are unlikely. ...Extreme upper TX/southwest LA coasts today... The remnant center of tropical depression Imelda continues to drift generally northward to the northwest of Houston. The primary confluence band has established near the coast to the south of the cyclone center. Earlier this morning, some mass response was apparent due to latent heat release with 30 kt low-level southerly flow just offshore, and a few rotating storms were noted just off the upper TX coast. However, the convection has developed a bit of a cold pool and more linear structure, and the 12z sounding from LCH immediately east of the main band shows limited potential for rotating storms, at best. While a brief/weak tornado cannot be completely ruled out, the overall threat appears too marginal to warrant the addition of an outlook area. ...Elsewhere... A few low-topped thunderstorms can be expected near the Pacific Northwest coast this morning, and spread inland during the day with the midlevel trough and steeper lapse rates. A few thunderstorms are also expected with a backdoor cold front that will move southwestward across GA/FL. ..Thompson/Kerr.. 09/18/2019 Read more