SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Thu Aug 14 2025 Valid 161200Z - 221200Z A trough will deepen across the Pacific Northwest D3/Saturday through D4/Sunday. Showers and thunderstorms will increase as a front shifts southward across Washington and Oregon, bringing showers and thunderstorms with primarily wetting rainfall. East of the Cascades, more of a mix of wet/dry thunderstorms will be possible. As the western high remains near Four Corners Region through D4/Sunday, continued deeper monsoonal moisture will bring wetting rainfall to moderate fuels across much of Arizona. On the periphery of this deeper moisture, isolated dry thunderstorms will be possible across portions of the Great Basin into the Northern Rockies. ...Dry Thunderstorms... A cold front will bring widespread wetting rainfall across much of the Pacific Northwest through the weekend. East of the Cascades, moisture will be more limited across southeastern Oregon. A 10 percent area was included with this outlook for D3/Saturday and D4/Sunday. With the aforementioned surface high into the Four Corners region, isolated dry thunderstorms will continue through the weekend into early next week on the fringe of the deeper monsoonal moisture surge across portions of central/northern Nevada into southern Idaho. Moisture will recede southward after the weekend, with drying and warming and less potential for precipitation with thunderstorms along the Mogollon Rim and in northern/central Arizona. This may warrant inclusion of probabilities when status of fuels after precipitation D2-D4 (Friday-Sunday) is known. ..Thornton.. 08/14/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC MD 1945

1 month ago
MD 1945 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EXTREME NORTHEAST NEVADA INTO CENTRAL AND NORTHERN UTAH...SOUTHEASTERN IDAHO...AND SOUTHWESTERN INTO CENTRAL WYOMING
Mesoscale Discussion 1945 NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Aug 14 2025 Areas affected...portions of extreme northeast Nevada into central and northern Utah...southeastern Idaho...and southwestern into central Wyoming Concerning...Severe potential...Watch unlikely Valid 141940Z - 142215Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorms will pose a risk for strong to potentially severe wind gusts through the afternoon and early evening hours. DISCUSSION...High-based thunderstorms are developing atop a dry boundary layer, where 40-50 T/Td spreads are already in place. RAP forecast soundings, and the DPG 18Z observed sounding, all depict inverted-v profiles extending up to 500 mb, with 20-40 kts of southwesterly flow constrained to the buoyant/cloud-bearing layer. Given 0-3 km lapse rates already exceeding 9 C/km in spots, conditions are favorable for fast-moving thunderstorms capable of producing dry downbursts, with strong erratic wind gusts possible. A few of these gusts may exceed 50 kts. However, the overall severe risk should remain widely scattered at best, so a Severe Thunderstorm Watch issuance is not currently anticipated. ..Squitieri/Mosier.. 08/14/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CYS...RIW...GJT...SLC...PIH...BOI...LKN... LAT...LON 41061505 42221408 43101190 43390988 42780847 42030786 41330795 40800836 40350875 39760983 39301126 39071219 39101288 39331355 39541411 39781450 40131495 41061505 MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more

SPC Aug 14, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 14 2025 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA...NORTHWEST MINNESOTA...AND FAR NORTHEAST SOUTH DAKOTA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. Isolated strong to severe gusts are also possible from the eastern Great Basin into the central Rockies. ...20Z Update... The forecast remains on track, and only minor changes were made with this update. Isolated to widely scattered thunderstorms are still expected along the cold front as it impinges on a destabilizing air mass across the northern Plains/Upper MS Valley tonight. Large hail and locally severe gusts will be possible with any organized clusters/supercells that evolve. Elsewhere, see MCDs 1944 and 1945 for details on the near-term severe risks in the Great Basin/central Rockies and Upper Midwest. ..Weinman.. 08/14/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Aug 14 2025/ ...Northern Plains into the Upper MS Valley... Recent surface analysis places a low over northwest ND, along a cold front arcing from west-central Manitoba into south-central MT. A surface trough also extends southward from this low to another weak low in southeast CO. Ample low-level moisture exists across the Plains east of this surface troughing, with mid 60s dewpoints extending up through central and eastern ND. Moist southerly low-level flow is forecast to persist throughout the day. This low-level moisture advection combined with evapotranspiration and low-level convergence near the front is expected to result in upper 60s to perhaps low 70s dewpoints ahead of the front across the eastern Dakotas by early evening. Cooling mid-level temperatures are expected across the region, which will combine with the abundant low-level moisture to support strong to very strong buoyancy by the late afternoon/early evening. Recent guidance suggests MLCAPE will range from 3000 to 4000 J/kg across the eastern Dakotas, western MN, and central/eastern NE by 00Z Friday. Despite this robust buoyancy, warm low to mid-level temperatures and related capping introduce uncertainty regarding convective initiation, particularly with southward extent. Greatest potential for convective initiation remains across eastern ND where glancing large-scale ascent attendant to the substantial shortwave trough moving through Saskatchewan will augment low-level convergence along the southeastward-progressing cold front. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Given the warm and dry low to mid-levels, strong downdrafts are possible as well. Upscale growth into clusters along the front is possible, and some damaging gusts could occur with these storms as well. Inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs, limiting the eastward extent of the severe threat. Additionally, the low-level jet will likely weaken throughout the day but then strengthen again later this evening from western KS into western IA. Associated warm-air advection could result in isolated elevated convection across central MN. Most of these storms should be sub-severe, but a few instances of hail are possible. ...Central High Plains/Central Plains... Scattered high-based thunderstorms should develop across the central Rockies this afternoon before the spreading eastward/southeastward into the central High Plains. A deeply mixed boundary layer and high cloud bases will support strong gusts with this activity as it moves across central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may reintensify, with the potential for severe gusts continuing into central NE. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Eastern Great Basin into central Rockies... The shortwave trough currently moving into central CA will continue eastward/southeastward throughout the day. Lift associated with this wave will interact with the modest mid-level moisture across the Great Basin to support scattered thunderstorm development. High cloud bases and a deeply mixed boundary layer could support strong downdrafts within the strongest storms, particularly across northern UT where the best overlap between forcing, buoyancy, and modest southwesterly flow aloft exists. Read more
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