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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Thu Sep 19 2024 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST INTO EASTERN KANSAS...WESTERN MISSOURI...AND FAR NORTHEAST OKLAHOMA... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon and evening across central/eastern Minnesota, Iowa, and western Wisconsin. A couple of tornadoes, large hail, and damaging winds may occur across this region. Farther south, an area of locally severe wind gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and northeast Oklahoma. ...20Z Update... The 18Z observed Minneapolis sounding showed steep mid-level lapse rates in addition to a long and predominantly straight hodograph. The expectation remains that a few supercells may initially develop from north-central Iowa into east-central Minnesota over the next 2-3 hours. These storms would pose the greatest risk for large/very-large hail. Given weak low-level shear evident on area VAD data in combination with linear forcing from the cold front, upscale growth should still occur quickly with a transition to more of a damaging wind threat. As this is in line with the thinking of the previous forecast, no changes have been made other than minor changes to the general thunderstorm area. See the previous discussion for further details. ..Wendt.. 09/19/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Thu Sep 19 2024/ ...Minnesota/Wisconsin/Iowa... Widely spaced and mainly elevated thunderstorms ongoing late this morning across parts of IA into eastern MN and western WI should continue to diminish in coverage over the next couple of hours. In their wake, daytime heating of a seasonably moist low-level airmass (surface dewpoints generally in the 60s) and somewhat steep mid-level lapse rates will contribute to at least moderate instability by mid afternoon along/ahead of a cold front extending north to south from western MN into eastern NE and western IA. An upper low over northern ND and southeast SK/southwest MB will continue to advance slowly northeastward across south-central Canada through the period. A belt of 35-50 kt mid-level west-southwesterly winds on the southern periphery of the upper low will spread eastward from the northern Plains into the Upper Midwest through this evening. A veering/strengthening wind profile with height through mid levels will support around 30-40 kt of deep-layer shear across the warm sector. This shear will be sufficient for organized thunderstorms, including the potential for a few supercells. Current expectations are that scattered thunderstorms will develop by mid to late afternoon across central/eastern MN into northern/central IA along or just ahead of the eastward-advancing cold front. A rather favorable thermodynamic environment will foster robust updrafts, and any initial supercells should pose a threat for large to very large hail (around 1.5-2.5 inches in diameter). But, a fairly quick transition to more linear structures should occur given the presence of the cold front, with a potentially greater damaging wind threat evolving with eastward extent through the evening before convection eventually weakens. South-southwesterly low-level flow and related shear ahead of the front is not forecast to be overly strong by most guidance this afternoon. But, some threat for a couple of tornadoes remains apparent, especially with any sustained supercells across east-central/southern MN into northern IA late this afternoon/early evening. ...Eastern Kansas into Missouri and Northeast Oklahoma... An upper ridge, with rather warm mid-level temperatures, will remain centered over the southern Plains today. The surface cold front is forecast to continue moving east-southeastward across the mid MO Valley and central Plains through late this afternoon. A surface trough extending southward from this front across the southern High Plains should also mix eastward through peak daytime heating. Given weak large-scale ascent and rather warm mid-level temperatures across this area, there is still a fair amount of uncertainty regarding how many additional thunderstorms will develop later today, notwithstanding the ongoing (mainly elevated) convection over eastern KS and far northwest MO. Still, other surface-based thunderstorms may develop later this afternoon along/near the front/dryline intersection in south-central KS/north-central OK, and along the cold front in eastern KS. While low/mid-level flow should remain fairly modest, steepened low-level lapse rates and moderate instability should support a risk for mainly severe/damaging downdrafts as convection spreads east-southeastward into western MO and northeast OK through this evening. Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...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 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more