Aggregator

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Apr 30 2024 Valid 301200Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSOURI VALLEY INTO THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley southwestward into the mid Missouri Valley, and central to southern Plains. The greatest threat is expected from western and central Iowa southwestward across far southeast Nebraska, far northwest Missouri into northeast Kansas, where very large hail, severe wind gusts (possibly above 70 mph) and a few tornadoes are expected. ...Upper Midwest/Mid Missouri Valley/Central Plains... An upper-level trough will move into the central and northern Plains today, as an associated 60 to 70 knot mid-level jet moves through the trough. At the surface, a deepening low will move into southeastern South Dakota, resulting in strong moisture advection across the mid Missouri Valley and central Plains. A north-northeast to south-southwest corridor of maximized low-level moisture will setup from eastern Kansas into western Iowa, where surface dewpoints will be in the lower to mid 60s F. Surface heating along this corridor will result in moderate instability by afternoon, with MLCAPE peaking in the 2000 to 3000 J/kg range. Ahead of the upper trough, large-scale ascent will likely support scattered thunderstorm development during the mid afternoon from eastern South Dakota into eastern Nebraska. This convection is expected to increase in intensity and coverage, moving eastward across Iowa, and developing south-southwestward into northeast Kansas during the late afternoon. A broken line of strong to severe storms will move east-southeastward toward the Mississippi River Valley in the early to mid evening. Along and near the instability axis, RAP forecast soundings at 21Z from near Omaha to Kansas City have supercell wind profiles, with strong speed shear in the low to midlevels and 0-6 km shear generally from 40 to 55 knots. Lapse rates are forecast to be very steep in the low to midlevels. 700-500 mb lapse rates around 8 C/km will be very favorable for supercells with large hail. The more dominant supercells should be capable of hailstones greater than 2 inches in diameter. 0-3 km lapse rates are forecast to be exceptionally steep, with some forecast soundings having 0-3 km lapse rates near 9 C/km. This should support a wind damage threat with supercells and the more intense short line segments. Wind gusts above 70 mph will be possible. Low-level shear should also be strong enough to support tornado development with the more intense supercells. The severe threat is expected to continue from late afternoon into the early to mid evening. The severe threat should become marginal by late evening, as the convective system moves through the lower Missouri Valley and southern sections of the central Plains. ...Southern Plains... West-southwesterly mid-level flow will be in place across the southern Plains today. At the surface, a corridor of maximized low-level moisture will be in place to the east of a dryline from western Oklahoma into west Texas. Surface dewpoints in the 60s F will contribute to the development of moderate instability by afternoon. MLCAPE is forecast to peak in the 2500 to 3500 J/kg range. Although large-scale ascent will likely be limited, low-level convergence near the dryline should result in isolated convective initiation during the mid to late afternoon. With any cell that can initiate and move away from the dryline, an isolated severe threat will be possible. RAP forecast soundings to the east of the dryline at 00Z/Wednesday generally have 0-6 km shear in the 30 to 40 knot range, with very steep lapse rates in the low to mid-levels. Some forecast soundings in western Oklahoma and northwest Texas have 0-3 km lapse rates near 9 C/km. This environment will likely be sufficient for organized cells with isolated large hail and strong gusts. The severe threat will be marginal from southwest Oklahoma into west Texas, where convective coverage is expected to be very isolated. ..Broyles/Thornton.. 04/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Apr 30 2024 Valid 301200Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSOURI VALLEY INTO THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley southwestward into the mid Missouri Valley, and central to southern Plains. The greatest threat is expected from western and central Iowa southwestward across far southeast Nebraska, far northwest Missouri into northeast Kansas, where very large hail, severe wind gusts (possibly above 70 mph) and a few tornadoes are expected. ...Upper Midwest/Mid Missouri Valley/Central Plains... An upper-level trough will move into the central and northern Plains today, as an associated 60 to 70 knot mid-level jet moves through the trough. At the surface, a deepening low will move into southeastern South Dakota, resulting in strong moisture advection across the mid Missouri Valley and central Plains. A north-northeast to south-southwest corridor of maximized low-level moisture will setup from eastern Kansas into western Iowa, where surface dewpoints will be in the lower to mid 60s F. Surface heating along this corridor will result in moderate instability by afternoon, with MLCAPE peaking in the 2000 to 3000 J/kg range. Ahead of the upper trough, large-scale ascent will likely support scattered thunderstorm development during the mid afternoon from eastern South Dakota into eastern Nebraska. This convection is expected to increase in intensity and coverage, moving eastward across Iowa, and developing south-southwestward into northeast Kansas during the late afternoon. A broken line of strong to severe storms will move east-southeastward toward the Mississippi River Valley in the early to mid evening. Along and near the instability axis, RAP forecast soundings at 21Z from near Omaha to Kansas City have supercell wind profiles, with strong speed shear in the low to midlevels and 0-6 km shear generally from 40 to 55 knots. Lapse rates are forecast to be very steep in the low to midlevels. 700-500 mb lapse rates around 8 C/km will be very favorable for supercells with large hail. The more dominant supercells should be capable of hailstones greater than 2 inches in diameter. 0-3 km lapse rates are forecast to be exceptionally steep, with some forecast soundings having 0-3 km lapse rates near 9 C/km. This should support a wind damage threat with supercells and the more intense short line segments. Wind gusts above 70 mph will be possible. Low-level shear should also be strong enough to support tornado development with the more intense supercells. The severe threat is expected to continue from late afternoon into the early to mid evening. The severe threat should become marginal by late evening, as the convective system moves through the lower Missouri Valley and southern sections of the central Plains. ...Southern Plains... West-southwesterly mid-level flow will be in place across the southern Plains today. At the surface, a corridor of maximized low-level moisture will be in place to the east of a dryline from western Oklahoma into west Texas. Surface dewpoints in the 60s F will contribute to the development of moderate instability by afternoon. MLCAPE is forecast to peak in the 2500 to 3500 J/kg range. Although large-scale ascent will likely be limited, low-level convergence near the dryline should result in isolated convective initiation during the mid to late afternoon. With any cell that can initiate and move away from the dryline, an isolated severe threat will be possible. RAP forecast soundings to the east of the dryline at 00Z/Wednesday generally have 0-6 km shear in the 30 to 40 knot range, with very steep lapse rates in the low to mid-levels. Some forecast soundings in western Oklahoma and northwest Texas have 0-3 km lapse rates near 9 C/km. This environment will likely be sufficient for organized cells with isolated large hail and strong gusts. The severe threat will be marginal from southwest Oklahoma into west Texas, where convective coverage is expected to be very isolated. ..Broyles/Thornton.. 04/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Apr 30 2024 Valid 301200Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSOURI VALLEY INTO THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley southwestward into the mid Missouri Valley, and central to southern Plains. The greatest threat is expected from western and central Iowa southwestward across far southeast Nebraska, far northwest Missouri into northeast Kansas, where very large hail, severe wind gusts (possibly above 70 mph) and a few tornadoes are expected. ...Upper Midwest/Mid Missouri Valley/Central Plains... An upper-level trough will move into the central and northern Plains today, as an associated 60 to 70 knot mid-level jet moves through the trough. At the surface, a deepening low will move into southeastern South Dakota, resulting in strong moisture advection across the mid Missouri Valley and central Plains. A north-northeast to south-southwest corridor of maximized low-level moisture will setup from eastern Kansas into western Iowa, where surface dewpoints will be in the lower to mid 60s F. Surface heating along this corridor will result in moderate instability by afternoon, with MLCAPE peaking in the 2000 to 3000 J/kg range. Ahead of the upper trough, large-scale ascent will likely support scattered thunderstorm development during the mid afternoon from eastern South Dakota into eastern Nebraska. This convection is expected to increase in intensity and coverage, moving eastward across Iowa, and developing south-southwestward into northeast Kansas during the late afternoon. A broken line of strong to severe storms will move east-southeastward toward the Mississippi River Valley in the early to mid evening. Along and near the instability axis, RAP forecast soundings at 21Z from near Omaha to Kansas City have supercell wind profiles, with strong speed shear in the low to midlevels and 0-6 km shear generally from 40 to 55 knots. Lapse rates are forecast to be very steep in the low to midlevels. 700-500 mb lapse rates around 8 C/km will be very favorable for supercells with large hail. The more dominant supercells should be capable of hailstones greater than 2 inches in diameter. 0-3 km lapse rates are forecast to be exceptionally steep, with some forecast soundings having 0-3 km lapse rates near 9 C/km. This should support a wind damage threat with supercells and the more intense short line segments. Wind gusts above 70 mph will be possible. Low-level shear should also be strong enough to support tornado development with the more intense supercells. The severe threat is expected to continue from late afternoon into the early to mid evening. The severe threat should become marginal by late evening, as the convective system moves through the lower Missouri Valley and southern sections of the central Plains. ...Southern Plains... West-southwesterly mid-level flow will be in place across the southern Plains today. At the surface, a corridor of maximized low-level moisture will be in place to the east of a dryline from western Oklahoma into west Texas. Surface dewpoints in the 60s F will contribute to the development of moderate instability by afternoon. MLCAPE is forecast to peak in the 2500 to 3500 J/kg range. Although large-scale ascent will likely be limited, low-level convergence near the dryline should result in isolated convective initiation during the mid to late afternoon. With any cell that can initiate and move away from the dryline, an isolated severe threat will be possible. RAP forecast soundings to the east of the dryline at 00Z/Wednesday generally have 0-6 km shear in the 30 to 40 knot range, with very steep lapse rates in the low to mid-levels. Some forecast soundings in western Oklahoma and northwest Texas have 0-3 km lapse rates near 9 C/km. This environment will likely be sufficient for organized cells with isolated large hail and strong gusts. The severe threat will be marginal from southwest Oklahoma into west Texas, where convective coverage is expected to be very isolated. ..Broyles/Thornton.. 04/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Mon Apr 29 2024 Valid 300100Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... No severe threat is expected this evening into tonight across the continental U.S. ...DISCUSSION... An upper-level trough will move across the Mississippi Valley this evening. At the surface, a moist airmass will be in place from the southern Plains and Southeast northward into the lower Great Lakes. Isolated to scattered thunderstorm development will be possible this evening into tonight across this moist airmass from the central Gulf Coast northward into the Ohio Valley and central Appalachians. Further west, isolated strong thunderstorms, associated with gusty winds and small hail, will be possible for another hour or so across south-central Texas. Thunderstorms may also develop across parts of the central and northern Rockies eastward into the northern High Plains. No appreciable severe threat is expected across the continental U.S. this evening and tonight. ..Broyles.. 04/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Mon Apr 29 2024 Valid 300100Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... No severe threat is expected this evening into tonight across the continental U.S. ...DISCUSSION... An upper-level trough will move across the Mississippi Valley this evening. At the surface, a moist airmass will be in place from the southern Plains and Southeast northward into the lower Great Lakes. Isolated to scattered thunderstorm development will be possible this evening into tonight across this moist airmass from the central Gulf Coast northward into the Ohio Valley and central Appalachians. Further west, isolated strong thunderstorms, associated with gusty winds and small hail, will be possible for another hour or so across south-central Texas. Thunderstorms may also develop across parts of the central and northern Rockies eastward into the northern High Plains. No appreciable severe threat is expected across the continental U.S. this evening and tonight. ..Broyles.. 04/30/2024 Read more

No watches are valid as of Mon Apr 29 22:35:01 UTC 2024.

No Mesoscale Discussions are in effect as of Mon Apr 29 22:35:01 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0411 PM CDT Mon Apr 29 2024 Valid 011200Z - 071200Z Mid-level flow will amplify across the western CONUS Wednesday and Thursday as a mid-level jet streak moves into the Inter Mountain West. As this occurs, lee cyclogenesis is expected which will make dry and breezy conditions likely across portions of the Southwest and southern High Plains Wednesday and Thursday. Beyond Thursday a broad trough is expected in the western CONUS but stronger mid-level flow and breezier conditions are not anticipated near dry fuels across the Southwest and southern High Plains until the early part of next week. However, there is considerable uncertainty in model guidance by that time which precludes any probabilities. ...Day3/Wednesday - D4/Thursday - southern High Plains... Dry and breezy conditions are expected across the Southwest and southern High Plains on Wednesday and Thursday in response to the developing lee cyclone, with additional support from the increasing mid-level flow over a deeply mixed airmass. Single digit relative humidity is likely both days. The strongest winds (20 to 25 mph sustained), is likely on Wednesday. In addition, most of this area has seen little to no precipitation over the past 2 weeks with additional drying expected on Tuesday. Therefore, Critical fire weather conditions are likely on Wednesday and Thursday. ..Bentley.. 04/29/2024 ...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 0411 PM CDT Mon Apr 29 2024 Valid 011200Z - 071200Z Mid-level flow will amplify across the western CONUS Wednesday and Thursday as a mid-level jet streak moves into the Inter Mountain West. As this occurs, lee cyclogenesis is expected which will make dry and breezy conditions likely across portions of the Southwest and southern High Plains Wednesday and Thursday. Beyond Thursday a broad trough is expected in the western CONUS but stronger mid-level flow and breezier conditions are not anticipated near dry fuels across the Southwest and southern High Plains until the early part of next week. However, there is considerable uncertainty in model guidance by that time which precludes any probabilities. ...Day3/Wednesday - D4/Thursday - southern High Plains... Dry and breezy conditions are expected across the Southwest and southern High Plains on Wednesday and Thursday in response to the developing lee cyclone, with additional support from the increasing mid-level flow over a deeply mixed airmass. Single digit relative humidity is likely both days. The strongest winds (20 to 25 mph sustained), is likely on Wednesday. In addition, most of this area has seen little to no precipitation over the past 2 weeks with additional drying expected on Tuesday. Therefore, Critical fire weather conditions are likely on Wednesday and Thursday. ..Bentley.. 04/29/2024 ...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 0411 PM CDT Mon Apr 29 2024 Valid 011200Z - 071200Z Mid-level flow will amplify across the western CONUS Wednesday and Thursday as a mid-level jet streak moves into the Inter Mountain West. As this occurs, lee cyclogenesis is expected which will make dry and breezy conditions likely across portions of the Southwest and southern High Plains Wednesday and Thursday. Beyond Thursday a broad trough is expected in the western CONUS but stronger mid-level flow and breezier conditions are not anticipated near dry fuels across the Southwest and southern High Plains until the early part of next week. However, there is considerable uncertainty in model guidance by that time which precludes any probabilities. ...Day3/Wednesday - D4/Thursday - southern High Plains... Dry and breezy conditions are expected across the Southwest and southern High Plains on Wednesday and Thursday in response to the developing lee cyclone, with additional support from the increasing mid-level flow over a deeply mixed airmass. Single digit relative humidity is likely both days. The strongest winds (20 to 25 mph sustained), is likely on Wednesday. In addition, most of this area has seen little to no precipitation over the past 2 weeks with additional drying expected on Tuesday. Therefore, Critical fire weather conditions are likely on Wednesday and Thursday. ..Bentley.. 04/29/2024 ...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 0259 PM CDT Mon Apr 29 2024 Valid 301200Z - 011200Z Added an Elevated delineation to portions of eastern Montana and southwest North Dakota. Minimal precipitation has fallen across this region over the past 2 weeks with significant drying of fine fuels. Some scattered showers/thunderstorms are possible tonight which may lead to wetting rain in some areas. However, this precipitation is expected to be sparse enough that dry fuels should remain tomorrow. Therefore, sustained 20 to 25 mph winds and relative humidity of 15 to 20 percent may result in some elevated large fire threat. ..Bentley.. 04/29/2024 .PREV DISCUSSION... /ISSUED 0154 AM CDT Mon Apr 29 2024/ ...Synopsis... A belt of enhanced mid-level flow will spread across the Northern Rockies from an upper-low across the northwestern US on Tuesday. A cold frontal passage will bring widespread wetting rainfall across much of eastern Montana and Wyoming. Behind the cold front, a dry continental air mass will overspread this region, with relative humidity dropping as low as 15 percent amid sustained winds 15-20 mph. Fuels in this region are expected to be marginal before additional rainfall. However, some potential for drying of grasses and fine fuels may support localized fire weather concerns. For now, this potential is too low to include any areas with this outlook. ...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 0259 PM CDT Mon Apr 29 2024 Valid 301200Z - 011200Z Added an Elevated delineation to portions of eastern Montana and southwest North Dakota. Minimal precipitation has fallen across this region over the past 2 weeks with significant drying of fine fuels. Some scattered showers/thunderstorms are possible tonight which may lead to wetting rain in some areas. However, this precipitation is expected to be sparse enough that dry fuels should remain tomorrow. Therefore, sustained 20 to 25 mph winds and relative humidity of 15 to 20 percent may result in some elevated large fire threat. ..Bentley.. 04/29/2024 .PREV DISCUSSION... /ISSUED 0154 AM CDT Mon Apr 29 2024/ ...Synopsis... A belt of enhanced mid-level flow will spread across the Northern Rockies from an upper-low across the northwestern US on Tuesday. A cold frontal passage will bring widespread wetting rainfall across much of eastern Montana and Wyoming. Behind the cold front, a dry continental air mass will overspread this region, with relative humidity dropping as low as 15 percent amid sustained winds 15-20 mph. Fuels in this region are expected to be marginal before additional rainfall. However, some potential for drying of grasses and fine fuels may support localized fire weather concerns. For now, this potential is too low to include any areas with this outlook. ...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 0259 PM CDT Mon Apr 29 2024 Valid 301200Z - 011200Z Added an Elevated delineation to portions of eastern Montana and southwest North Dakota. Minimal precipitation has fallen across this region over the past 2 weeks with significant drying of fine fuels. Some scattered showers/thunderstorms are possible tonight which may lead to wetting rain in some areas. However, this precipitation is expected to be sparse enough that dry fuels should remain tomorrow. Therefore, sustained 20 to 25 mph winds and relative humidity of 15 to 20 percent may result in some elevated large fire threat. ..Bentley.. 04/29/2024 .PREV DISCUSSION... /ISSUED 0154 AM CDT Mon Apr 29 2024/ ...Synopsis... A belt of enhanced mid-level flow will spread across the Northern Rockies from an upper-low across the northwestern US on Tuesday. A cold frontal passage will bring widespread wetting rainfall across much of eastern Montana and Wyoming. Behind the cold front, a dry continental air mass will overspread this region, with relative humidity dropping as low as 15 percent amid sustained winds 15-20 mph. Fuels in this region are expected to be marginal before additional rainfall. However, some potential for drying of grasses and fine fuels may support localized fire weather concerns. For now, this potential is too low to include any areas with this outlook. ...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 0252 PM CDT Mon Apr 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MS VALLEY...SOUTH TEXAS...AND SOUTHEAST LOWER MI... ...SUMMARY... Marginally severe wind gusts and hail will be possible today across south Texas, the lower Mississippi Valley and southeast Lower Michigan. ...20Z Update... Overall forecast reasoning remains unchanged. Only adjustment to the previous outlook was to trim behind the line in southern MS. Ongoing line across southwest IN will likely continue eastward/northeastward. Widespread clouds have limited heating downstream across IN and OH, which has limited buoyancy as well. This limited buoyancy should temper the overall severe potential, although a damaging gust or two is possible if storms briefly intensify. ..Mosier.. 04/29/2024 .PREV DISCUSSION... /ISSUED 1113 AM CDT Mon Apr 29 2024/ ...LA/MS/AL... A decaying linear MCS is moving slowly southeastward across southern LA, with the most active part of the line well offshore. The leading outflow boundary extends northward across southeast LA into central MS, with a warm/moist low-level air mass in place to the east. Some rejuvenation of thunderstorms along this line is expected this afternoon, with storms tracking eastward toward southwest AL this evening. Mid-level lapse rates are weak in this area, along with weak to moderately strong low to mid-level wind fields. This suggests some risk of gusty or possibly damaging winds with these storms, but the threat is expected to remain rather isolated. ...Southeast Lower MI... Visible satellite imagery shows strong heating occurring over southeast Lower MI today, but with a broad area of clouds and light precipitation approaching from the southwest. Several morning CAM solutions show scattered afternoon thunderstorms developing along the leading edge of this cloud deck. Storms will sweep across the area rather quickly, with steepening low-level lapse rates posing a risk of locally gusty/damaging wind gusts in the strongest cells. An isolated tornado cannot be ruled out as well - especially along a surface boundary that extends across the Thumb area. ...South TX... A moist and moderately unstable air mass is present today across south TX, ahead of a weak front. The coverage of thunderstorms is expected to be quite limited today in this region, but any storm that forms could pose a risk of large hail for a few hours. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Mon Apr 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MS VALLEY...SOUTH TEXAS...AND SOUTHEAST LOWER MI... ...SUMMARY... Marginally severe wind gusts and hail will be possible today across south Texas, the lower Mississippi Valley and southeast Lower Michigan. ...20Z Update... Overall forecast reasoning remains unchanged. Only adjustment to the previous outlook was to trim behind the line in southern MS. Ongoing line across southwest IN will likely continue eastward/northeastward. Widespread clouds have limited heating downstream across IN and OH, which has limited buoyancy as well. This limited buoyancy should temper the overall severe potential, although a damaging gust or two is possible if storms briefly intensify. ..Mosier.. 04/29/2024 .PREV DISCUSSION... /ISSUED 1113 AM CDT Mon Apr 29 2024/ ...LA/MS/AL... A decaying linear MCS is moving slowly southeastward across southern LA, with the most active part of the line well offshore. The leading outflow boundary extends northward across southeast LA into central MS, with a warm/moist low-level air mass in place to the east. Some rejuvenation of thunderstorms along this line is expected this afternoon, with storms tracking eastward toward southwest AL this evening. Mid-level lapse rates are weak in this area, along with weak to moderately strong low to mid-level wind fields. This suggests some risk of gusty or possibly damaging winds with these storms, but the threat is expected to remain rather isolated. ...Southeast Lower MI... Visible satellite imagery shows strong heating occurring over southeast Lower MI today, but with a broad area of clouds and light precipitation approaching from the southwest. Several morning CAM solutions show scattered afternoon thunderstorms developing along the leading edge of this cloud deck. Storms will sweep across the area rather quickly, with steepening low-level lapse rates posing a risk of locally gusty/damaging wind gusts in the strongest cells. An isolated tornado cannot be ruled out as well - especially along a surface boundary that extends across the Thumb area. ...South TX... A moist and moderately unstable air mass is present today across south TX, ahead of a weak front. The coverage of thunderstorms is expected to be quite limited today in this region, but any storm that forms could pose a risk of large hail for a few hours. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Mon Apr 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MS VALLEY...SOUTH TEXAS...AND SOUTHEAST LOWER MI... ...SUMMARY... Marginally severe wind gusts and hail will be possible today across south Texas, the lower Mississippi Valley and southeast Lower Michigan. ...20Z Update... Overall forecast reasoning remains unchanged. Only adjustment to the previous outlook was to trim behind the line in southern MS. Ongoing line across southwest IN will likely continue eastward/northeastward. Widespread clouds have limited heating downstream across IN and OH, which has limited buoyancy as well. This limited buoyancy should temper the overall severe potential, although a damaging gust or two is possible if storms briefly intensify. ..Mosier.. 04/29/2024 .PREV DISCUSSION... /ISSUED 1113 AM CDT Mon Apr 29 2024/ ...LA/MS/AL... A decaying linear MCS is moving slowly southeastward across southern LA, with the most active part of the line well offshore. The leading outflow boundary extends northward across southeast LA into central MS, with a warm/moist low-level air mass in place to the east. Some rejuvenation of thunderstorms along this line is expected this afternoon, with storms tracking eastward toward southwest AL this evening. Mid-level lapse rates are weak in this area, along with weak to moderately strong low to mid-level wind fields. This suggests some risk of gusty or possibly damaging winds with these storms, but the threat is expected to remain rather isolated. ...Southeast Lower MI... Visible satellite imagery shows strong heating occurring over southeast Lower MI today, but with a broad area of clouds and light precipitation approaching from the southwest. Several morning CAM solutions show scattered afternoon thunderstorms developing along the leading edge of this cloud deck. Storms will sweep across the area rather quickly, with steepening low-level lapse rates posing a risk of locally gusty/damaging wind gusts in the strongest cells. An isolated tornado cannot be ruled out as well - especially along a surface boundary that extends across the Thumb area. ...South TX... A moist and moderately unstable air mass is present today across south TX, ahead of a weak front. The coverage of thunderstorms is expected to be quite limited today in this region, but any storm that forms could pose a risk of large hail for a few hours. Read more

MD 0572 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR THE MICHIGAN THUMB VICINITY
Mesoscale Discussion 0572 NWS Storm Prediction Center Norman OK 1258 PM CDT Mon Apr 29 2024 Areas affected...the Michigan Thumb vicinity Concerning...Severe potential...Watch unlikely Valid 291758Z - 292000Z Probability of Watch Issuance...20 percent SUMMARY...The evolution of an isolated supercell accompanied by at least some potential for a tornado, in addition severe hail and wind, appears possible across the Michigan Thumb vicinity near Bad Axe through 3-5 PM EDT. DISCUSSION...Downstream of larger-scale mid-level troughing, with an embedded low, migrating northeastward into/through the Upper Midwest/Great Lakes vicinity, a strong south-southwesterly mid-level jet (40-70 kt in the 700-500 mb layer) is in the process of propagating across lower Michigan. In association with this feature, an area of stronger surface pressure falls (2-3+ mb 2 hourly) has generally begun to shift across Lake Huron, but still extends along an axis as far south as the Flint MI vicinity. This is near a weak surface frontal low which is forecast to migrate across and northeast of the Bad Axe vicinity through 19-21Z. South of the front, boundary-layer moistening (including surface dew points around 60f) has been sufficient to contribute to weak destabilization (including mixed-layer CAPE increasing up to 500 J/kg). Although further heating and mixing may reduce this some to the south of the front, this may be maintained along the front, just ahead of the low, which may gradually provide a focus for intensifying convection. Given the strength of the vertical shear, including sizable clockwise-curved low-level hodographs, and localized forcing for ascent, the evolution of a supercell appears possible, which may pose at least some risk for producing a tornado, in addition to marginally severe hail and wind. ..Kerr/Hart.. 04/29/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX... LAT...LON 43518375 44018294 43788262 43438274 43228323 43248368 43518375 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Mon Apr 29 2024 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHWEST MN...WESTERN IA...FAR NORTHWEST MO...EASTERN KS...EASTERN NE AND FAR SOUTHEAST SD... ...SUMMARY... Severe thunderstorms will be possible on Tuesday from parts of the mid/upper Mississippi Valley into the central/southern Plains. The greatest threat is expected from eastern Nebraska into parts of western Iowa and southwest Minnesota, with a risk of very large hail, severe wind gusts, and a few tornadoes. ...Synopsis... An upper cyclone is forecast to be centered over southeastern British Columbia/southwest Alberta early Tuesday morning. A series of shortwave troughs are expected to traverse the moderate mid-level flow is extended throughout the base of this cyclone. The lead wave in this series will likely move from the central High Plains northeastward across the northern/central Plains into the Upper Midwest throughout the day, accompanied by gradually strengthening mid-level flow. A weak cold front and associated surface troughing will precede this shortwave, with consolidation into more prominent low anticipated from the Mid MO Valley into the Upper Midwest during the afternoon and evening. Northern portion of this front near the surface low will remain progressive, continuing eastward through the Upper Midwest overnight. However, southern portion of the front will slow and eventually stall across KS, with additional surface cyclogenesis possible along the western portion of this boundary over western KS and the eastern TX/OK Panhandles. Farther east, a shortwave trough is expected to gradually shift eastward from the Lower OH Valley/Mid-South across the TN Valley and Southeast states, reaching the Mid-Atlantic States by early Wednesday morning. Some phasing between this wave and a separate low-amplitude shortwave farther north over the Lower Great Lakes/southwestern Ontario is possible. Isolated thunderstorms are anticipated ahead of both of these waves across much of the eastern CONUS (i.e. from the Upper OH Valley/Northeast States into the Southeast). However, limited buoyancy and weak shear should temper the overall severe potential across the majority of the area, although a locally increased risk is possible from central NY through eastern PA and from eastern GA through SC. ...Mid MO Valley into Eastern KS... Low-level moisture is expected to advect quickly northward throughout the day, ahead of the approaching shortwave trough and associated surface trough/cold front. Consensus among the guidance brings low 60s dewpoints into the northeastern KS/northwest MO/southeastern NE border vicinity by the mid afternoon, with upper 50s northward along the NE/IA border. This low-level moisture combined with modest daytime heating and steep mid-level lapse rates will support moderate buoyancy (i.e. 1500 to 2000 J/kg). Thunderstorm development is anticipated along the front during the afternoon, beginning across eastern SD/southwestern MN then extending southwestward across eastern NE. Given the moderate buoyancy, robust updrafts should develop quickly, and vertical shear will be strong enough to support organized storm structures. Large to very large hail is likely with initial development before the storms undergo a relatively quick upscale growth, with the transition to a more linear mode favoring strong gusts. Some gusts to 75 mph are possible. The tornado threat is a bit more complex. There is enough low-level curvature to support tornadogenesis, but the overall potential may be limited by the quick upscale growth and relatively short time duration storms will be in a discrete mode. That being said, some tornado threat is possible within the line as well, particularly across western IA during the early evening (i.e. around 00Z) as the low-level jet increases. ...Central KS southwestward across Western OK into Southwest TX... Most of the stronger large-scale forcing for ascent is anticipated farther north, but persistent low-level convergence along the dryline could result in isolated to widely scattered thunderstorm initiation. Any storms that mature could produce large to very large hail and damaging downbursts. Guidance has trended towards a bit more thunderstorm coverage from northwest into southwest TX, but the lack of stronger large scale forcing limits forecast confidence, precluding the introduction of higher probabilities with this outlook. ..Mosier.. 04/29/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Mon Apr 29 2024 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHWEST MN...WESTERN IA...FAR NORTHWEST MO...EASTERN KS...EASTERN NE AND FAR SOUTHEAST SD... ...SUMMARY... Severe thunderstorms will be possible on Tuesday from parts of the mid/upper Mississippi Valley into the central/southern Plains. The greatest threat is expected from eastern Nebraska into parts of western Iowa and southwest Minnesota, with a risk of very large hail, severe wind gusts, and a few tornadoes. ...Synopsis... An upper cyclone is forecast to be centered over southeastern British Columbia/southwest Alberta early Tuesday morning. A series of shortwave troughs are expected to traverse the moderate mid-level flow is extended throughout the base of this cyclone. The lead wave in this series will likely move from the central High Plains northeastward across the northern/central Plains into the Upper Midwest throughout the day, accompanied by gradually strengthening mid-level flow. A weak cold front and associated surface troughing will precede this shortwave, with consolidation into more prominent low anticipated from the Mid MO Valley into the Upper Midwest during the afternoon and evening. Northern portion of this front near the surface low will remain progressive, continuing eastward through the Upper Midwest overnight. However, southern portion of the front will slow and eventually stall across KS, with additional surface cyclogenesis possible along the western portion of this boundary over western KS and the eastern TX/OK Panhandles. Farther east, a shortwave trough is expected to gradually shift eastward from the Lower OH Valley/Mid-South across the TN Valley and Southeast states, reaching the Mid-Atlantic States by early Wednesday morning. Some phasing between this wave and a separate low-amplitude shortwave farther north over the Lower Great Lakes/southwestern Ontario is possible. Isolated thunderstorms are anticipated ahead of both of these waves across much of the eastern CONUS (i.e. from the Upper OH Valley/Northeast States into the Southeast). However, limited buoyancy and weak shear should temper the overall severe potential across the majority of the area, although a locally increased risk is possible from central NY through eastern PA and from eastern GA through SC. ...Mid MO Valley into Eastern KS... Low-level moisture is expected to advect quickly northward throughout the day, ahead of the approaching shortwave trough and associated surface trough/cold front. Consensus among the guidance brings low 60s dewpoints into the northeastern KS/northwest MO/southeastern NE border vicinity by the mid afternoon, with upper 50s northward along the NE/IA border. This low-level moisture combined with modest daytime heating and steep mid-level lapse rates will support moderate buoyancy (i.e. 1500 to 2000 J/kg). Thunderstorm development is anticipated along the front during the afternoon, beginning across eastern SD/southwestern MN then extending southwestward across eastern NE. Given the moderate buoyancy, robust updrafts should develop quickly, and vertical shear will be strong enough to support organized storm structures. Large to very large hail is likely with initial development before the storms undergo a relatively quick upscale growth, with the transition to a more linear mode favoring strong gusts. Some gusts to 75 mph are possible. The tornado threat is a bit more complex. There is enough low-level curvature to support tornadogenesis, but the overall potential may be limited by the quick upscale growth and relatively short time duration storms will be in a discrete mode. That being said, some tornado threat is possible within the line as well, particularly across western IA during the early evening (i.e. around 00Z) as the low-level jet increases. ...Central KS southwestward across Western OK into Southwest TX... Most of the stronger large-scale forcing for ascent is anticipated farther north, but persistent low-level convergence along the dryline could result in isolated to widely scattered thunderstorm initiation. Any storms that mature could produce large to very large hail and damaging downbursts. Guidance has trended towards a bit more thunderstorm coverage from northwest into southwest TX, but the lack of stronger large scale forcing limits forecast confidence, precluding the introduction of higher probabilities with this outlook. ..Mosier.. 04/29/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Mon Apr 29 2024 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHWEST MN...WESTERN IA...FAR NORTHWEST MO...EASTERN KS...EASTERN NE AND FAR SOUTHEAST SD... ...SUMMARY... Severe thunderstorms will be possible on Tuesday from parts of the mid/upper Mississippi Valley into the central/southern Plains. The greatest threat is expected from eastern Nebraska into parts of western Iowa and southwest Minnesota, with a risk of very large hail, severe wind gusts, and a few tornadoes. ...Synopsis... An upper cyclone is forecast to be centered over southeastern British Columbia/southwest Alberta early Tuesday morning. A series of shortwave troughs are expected to traverse the moderate mid-level flow is extended throughout the base of this cyclone. The lead wave in this series will likely move from the central High Plains northeastward across the northern/central Plains into the Upper Midwest throughout the day, accompanied by gradually strengthening mid-level flow. A weak cold front and associated surface troughing will precede this shortwave, with consolidation into more prominent low anticipated from the Mid MO Valley into the Upper Midwest during the afternoon and evening. Northern portion of this front near the surface low will remain progressive, continuing eastward through the Upper Midwest overnight. However, southern portion of the front will slow and eventually stall across KS, with additional surface cyclogenesis possible along the western portion of this boundary over western KS and the eastern TX/OK Panhandles. Farther east, a shortwave trough is expected to gradually shift eastward from the Lower OH Valley/Mid-South across the TN Valley and Southeast states, reaching the Mid-Atlantic States by early Wednesday morning. Some phasing between this wave and a separate low-amplitude shortwave farther north over the Lower Great Lakes/southwestern Ontario is possible. Isolated thunderstorms are anticipated ahead of both of these waves across much of the eastern CONUS (i.e. from the Upper OH Valley/Northeast States into the Southeast). However, limited buoyancy and weak shear should temper the overall severe potential across the majority of the area, although a locally increased risk is possible from central NY through eastern PA and from eastern GA through SC. ...Mid MO Valley into Eastern KS... Low-level moisture is expected to advect quickly northward throughout the day, ahead of the approaching shortwave trough and associated surface trough/cold front. Consensus among the guidance brings low 60s dewpoints into the northeastern KS/northwest MO/southeastern NE border vicinity by the mid afternoon, with upper 50s northward along the NE/IA border. This low-level moisture combined with modest daytime heating and steep mid-level lapse rates will support moderate buoyancy (i.e. 1500 to 2000 J/kg). Thunderstorm development is anticipated along the front during the afternoon, beginning across eastern SD/southwestern MN then extending southwestward across eastern NE. Given the moderate buoyancy, robust updrafts should develop quickly, and vertical shear will be strong enough to support organized storm structures. Large to very large hail is likely with initial development before the storms undergo a relatively quick upscale growth, with the transition to a more linear mode favoring strong gusts. Some gusts to 75 mph are possible. The tornado threat is a bit more complex. There is enough low-level curvature to support tornadogenesis, but the overall potential may be limited by the quick upscale growth and relatively short time duration storms will be in a discrete mode. That being said, some tornado threat is possible within the line as well, particularly across western IA during the early evening (i.e. around 00Z) as the low-level jet increases. ...Central KS southwestward across Western OK into Southwest TX... Most of the stronger large-scale forcing for ascent is anticipated farther north, but persistent low-level convergence along the dryline could result in isolated to widely scattered thunderstorm initiation. Any storms that mature could produce large to very large hail and damaging downbursts. Guidance has trended towards a bit more thunderstorm coverage from northwest into southwest TX, but the lack of stronger large scale forcing limits forecast confidence, precluding the introduction of higher probabilities with this outlook. ..Mosier.. 04/29/2024 Read more