Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0735 AM CDT Thu Jul 17 2025 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND NORTHERN HIGH PLAINS... ...SUMMARY... Scattered damaging winds and a brief tornado are possible across northern New England this afternoon. Isolated/sporadic damaging winds may also occur across a broad swath of the Northeast/Mid-Atlantic to the southern High Plains. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...Northeast... The Slight Risk has been maintained across this region with no changes. A shortwave trough will move northeastward from the Upper Great Lakes to the Ontario/Quebec border vicinity by this evening. A broad swath of enhanced 850-700 mb west-southwesterly winds is forecast from PA/NJ northward into New England. Further weakening of already poor mid-level lapse rates is anticipated across parts of southern NY into southern New England. This may tend to limit convective coverage across the northern Mid-Atlantic to southern New England vicinity. But, farther north and in closer proximity to ascent associated with the approaching mid-level shortwave trough, scattered robust convection is anticipated this afternoon along the Quebec border across northern New England. Sufficient instability and deep-layer shear are forecast across this region to support a mix of multicells and perhaps marginal supercells. Given the enhanced low/mid-level flow, scattered damaging winds should be the main threat with this activity as it moves generally east-northeastward through the early evening, before eventually weakening as it approaches the coast. Enough low-level hodograph enlargement/curvature may also be present to support some risk for a tornado or two. ...Mid-Atlantic to the Southern High Plains... Extensive convection is ongoing this morning across south-central/southeast KS into MO. This activity should generally remain sub-severe, but it will help reinforce a front that is expected to gradually sag southward and eventually stall across the mid MS Valley to southern Plains today. Scattered to numerous thunderstorms are expected to develop west of the Appalachians along this boundary later this afternoon as diurnal heating occurs. Moderate to strong instability amid steepened low-level rates along/south of the outflow/front should support sporadic wet microbursts. Isolated hail will be possible with thunderstorms in the post-frontal upslope flow regime across parts of the southern High Plains. But, modest deep-layer shear and warm temperatures aloft across all these regions should temper the overall intensity/coverage of severe convection. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. ...Northern Plains... A narrow corridor of supercell potential remains evident across north-central MT to southwest ND, mainly this evening. A positively tilted mid-level shortwave trough over the southern Canadian Rockies will progress eastward along the international border with MT/ND today. Mid to late afternoon convective initiation should occur over parts of southwest Alberta in association with this feature. A confined plume of weak buoyancy ahead of this activity should initially temper updraft intensity as it spreads east-southeastward into north-central MT by late afternoon. But, favorably timed strengthening of a 500-mb westerly jet over MT will aid in hodograph elongation at mid/upper levels this evening. This could support a long-lived supercell or two during the evening, impinging on the nose of moderate instability that should be present across southeast MT. Large hail should be the main threat with these supercells if they can be maintained. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ..Gleason/Bentley.. 07/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0735 AM CDT Thu Jul 17 2025 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND NORTHERN HIGH PLAINS... ...SUMMARY... Scattered damaging winds and a brief tornado are possible across northern New England this afternoon. Isolated/sporadic damaging winds may also occur across a broad swath of the Northeast/Mid-Atlantic to the southern High Plains. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...Northeast... The Slight Risk has been maintained across this region with no changes. A shortwave trough will move northeastward from the Upper Great Lakes to the Ontario/Quebec border vicinity by this evening. A broad swath of enhanced 850-700 mb west-southwesterly winds is forecast from PA/NJ northward into New England. Further weakening of already poor mid-level lapse rates is anticipated across parts of southern NY into southern New England. This may tend to limit convective coverage across the northern Mid-Atlantic to southern New England vicinity. But, farther north and in closer proximity to ascent associated with the approaching mid-level shortwave trough, scattered robust convection is anticipated this afternoon along the Quebec border across northern New England. Sufficient instability and deep-layer shear are forecast across this region to support a mix of multicells and perhaps marginal supercells. Given the enhanced low/mid-level flow, scattered damaging winds should be the main threat with this activity as it moves generally east-northeastward through the early evening, before eventually weakening as it approaches the coast. Enough low-level hodograph enlargement/curvature may also be present to support some risk for a tornado or two. ...Mid-Atlantic to the Southern High Plains... Extensive convection is ongoing this morning across south-central/southeast KS into MO. This activity should generally remain sub-severe, but it will help reinforce a front that is expected to gradually sag southward and eventually stall across the mid MS Valley to southern Plains today. Scattered to numerous thunderstorms are expected to develop west of the Appalachians along this boundary later this afternoon as diurnal heating occurs. Moderate to strong instability amid steepened low-level rates along/south of the outflow/front should support sporadic wet microbursts. Isolated hail will be possible with thunderstorms in the post-frontal upslope flow regime across parts of the southern High Plains. But, modest deep-layer shear and warm temperatures aloft across all these regions should temper the overall intensity/coverage of severe convection. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. ...Northern Plains... A narrow corridor of supercell potential remains evident across north-central MT to southwest ND, mainly this evening. A positively tilted mid-level shortwave trough over the southern Canadian Rockies will progress eastward along the international border with MT/ND today. Mid to late afternoon convective initiation should occur over parts of southwest Alberta in association with this feature. A confined plume of weak buoyancy ahead of this activity should initially temper updraft intensity as it spreads east-southeastward into north-central MT by late afternoon. But, favorably timed strengthening of a 500-mb westerly jet over MT will aid in hodograph elongation at mid/upper levels this evening. This could support a long-lived supercell or two during the evening, impinging on the nose of moderate instability that should be present across southeast MT. Large hail should be the main threat with these supercells if they can be maintained. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ..Gleason/Bentley.. 07/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0735 AM CDT Thu Jul 17 2025 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND NORTHERN HIGH PLAINS... ...SUMMARY... Scattered damaging winds and a brief tornado are possible across northern New England this afternoon. Isolated/sporadic damaging winds may also occur across a broad swath of the Northeast/Mid-Atlantic to the southern High Plains. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...Northeast... The Slight Risk has been maintained across this region with no changes. A shortwave trough will move northeastward from the Upper Great Lakes to the Ontario/Quebec border vicinity by this evening. A broad swath of enhanced 850-700 mb west-southwesterly winds is forecast from PA/NJ northward into New England. Further weakening of already poor mid-level lapse rates is anticipated across parts of southern NY into southern New England. This may tend to limit convective coverage across the northern Mid-Atlantic to southern New England vicinity. But, farther north and in closer proximity to ascent associated with the approaching mid-level shortwave trough, scattered robust convection is anticipated this afternoon along the Quebec border across northern New England. Sufficient instability and deep-layer shear are forecast across this region to support a mix of multicells and perhaps marginal supercells. Given the enhanced low/mid-level flow, scattered damaging winds should be the main threat with this activity as it moves generally east-northeastward through the early evening, before eventually weakening as it approaches the coast. Enough low-level hodograph enlargement/curvature may also be present to support some risk for a tornado or two. ...Mid-Atlantic to the Southern High Plains... Extensive convection is ongoing this morning across south-central/southeast KS into MO. This activity should generally remain sub-severe, but it will help reinforce a front that is expected to gradually sag southward and eventually stall across the mid MS Valley to southern Plains today. Scattered to numerous thunderstorms are expected to develop west of the Appalachians along this boundary later this afternoon as diurnal heating occurs. Moderate to strong instability amid steepened low-level rates along/south of the outflow/front should support sporadic wet microbursts. Isolated hail will be possible with thunderstorms in the post-frontal upslope flow regime across parts of the southern High Plains. But, modest deep-layer shear and warm temperatures aloft across all these regions should temper the overall intensity/coverage of severe convection. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. ...Northern Plains... A narrow corridor of supercell potential remains evident across north-central MT to southwest ND, mainly this evening. A positively tilted mid-level shortwave trough over the southern Canadian Rockies will progress eastward along the international border with MT/ND today. Mid to late afternoon convective initiation should occur over parts of southwest Alberta in association with this feature. A confined plume of weak buoyancy ahead of this activity should initially temper updraft intensity as it spreads east-southeastward into north-central MT by late afternoon. But, favorably timed strengthening of a 500-mb westerly jet over MT will aid in hodograph elongation at mid/upper levels this evening. This could support a long-lived supercell or two during the evening, impinging on the nose of moderate instability that should be present across southeast MT. Large hail should be the main threat with these supercells if they can be maintained. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ..Gleason/Bentley.. 07/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0735 AM CDT Thu Jul 17 2025 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND NORTHERN HIGH PLAINS... ...SUMMARY... Scattered damaging winds and a brief tornado are possible across northern New England this afternoon. Isolated/sporadic damaging winds may also occur across a broad swath of the Northeast/Mid-Atlantic to the southern High Plains. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...Northeast... The Slight Risk has been maintained across this region with no changes. A shortwave trough will move northeastward from the Upper Great Lakes to the Ontario/Quebec border vicinity by this evening. A broad swath of enhanced 850-700 mb west-southwesterly winds is forecast from PA/NJ northward into New England. Further weakening of already poor mid-level lapse rates is anticipated across parts of southern NY into southern New England. This may tend to limit convective coverage across the northern Mid-Atlantic to southern New England vicinity. But, farther north and in closer proximity to ascent associated with the approaching mid-level shortwave trough, scattered robust convection is anticipated this afternoon along the Quebec border across northern New England. Sufficient instability and deep-layer shear are forecast across this region to support a mix of multicells and perhaps marginal supercells. Given the enhanced low/mid-level flow, scattered damaging winds should be the main threat with this activity as it moves generally east-northeastward through the early evening, before eventually weakening as it approaches the coast. Enough low-level hodograph enlargement/curvature may also be present to support some risk for a tornado or two. ...Mid-Atlantic to the Southern High Plains... Extensive convection is ongoing this morning across south-central/southeast KS into MO. This activity should generally remain sub-severe, but it will help reinforce a front that is expected to gradually sag southward and eventually stall across the mid MS Valley to southern Plains today. Scattered to numerous thunderstorms are expected to develop west of the Appalachians along this boundary later this afternoon as diurnal heating occurs. Moderate to strong instability amid steepened low-level rates along/south of the outflow/front should support sporadic wet microbursts. Isolated hail will be possible with thunderstorms in the post-frontal upslope flow regime across parts of the southern High Plains. But, modest deep-layer shear and warm temperatures aloft across all these regions should temper the overall intensity/coverage of severe convection. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. ...Northern Plains... A narrow corridor of supercell potential remains evident across north-central MT to southwest ND, mainly this evening. A positively tilted mid-level shortwave trough over the southern Canadian Rockies will progress eastward along the international border with MT/ND today. Mid to late afternoon convective initiation should occur over parts of southwest Alberta in association with this feature. A confined plume of weak buoyancy ahead of this activity should initially temper updraft intensity as it spreads east-southeastward into north-central MT by late afternoon. But, favorably timed strengthening of a 500-mb westerly jet over MT will aid in hodograph elongation at mid/upper levels this evening. This could support a long-lived supercell or two during the evening, impinging on the nose of moderate instability that should be present across southeast MT. Large hail should be the main threat with these supercells if they can be maintained. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ..Gleason/Bentley.. 07/17/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0231 AM CDT Thu Jul 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Upper ridging will build across much of the CONUS during the Day 4-8 period. However, progressive, but low-amplitude westerly northern stream flow will continue atop the upper ridge across the northern tier of the U.S. This overall pattern will favor bouts of strong to severe thunderstorms within west/northwesterly flow aloft from the northern Plains into portions of the Midwest. However, given subtle forcing mechanisms, this activity will be driven by mesoscale processes/features (MCVs from prior convection, modifying outflow boundaries, etc) that are more uncertain at longer forecast times. As such, predictability is too low for delineating areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0231 AM CDT Thu Jul 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Upper ridging will build across much of the CONUS during the Day 4-8 period. However, progressive, but low-amplitude westerly northern stream flow will continue atop the upper ridge across the northern tier of the U.S. This overall pattern will favor bouts of strong to severe thunderstorms within west/northwesterly flow aloft from the northern Plains into portions of the Midwest. However, given subtle forcing mechanisms, this activity will be driven by mesoscale processes/features (MCVs from prior convection, modifying outflow boundaries, etc) that are more uncertain at longer forecast times. As such, predictability is too low for delineating areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0231 AM CDT Thu Jul 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Upper ridging will build across much of the CONUS during the Day 4-8 period. However, progressive, but low-amplitude westerly northern stream flow will continue atop the upper ridge across the northern tier of the U.S. This overall pattern will favor bouts of strong to severe thunderstorms within west/northwesterly flow aloft from the northern Plains into portions of the Midwest. However, given subtle forcing mechanisms, this activity will be driven by mesoscale processes/features (MCVs from prior convection, modifying outflow boundaries, etc) that are more uncertain at longer forecast times. As such, predictability is too low for delineating areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0231 AM CDT Thu Jul 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Upper ridging will build across much of the CONUS during the Day 4-8 period. However, progressive, but low-amplitude westerly northern stream flow will continue atop the upper ridge across the northern tier of the U.S. This overall pattern will favor bouts of strong to severe thunderstorms within west/northwesterly flow aloft from the northern Plains into portions of the Midwest. However, given subtle forcing mechanisms, this activity will be driven by mesoscale processes/features (MCVs from prior convection, modifying outflow boundaries, etc) that are more uncertain at longer forecast times. As such, predictability is too low for delineating areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0231 AM CDT Thu Jul 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Upper ridging will build across much of the CONUS during the Day 4-8 period. However, progressive, but low-amplitude westerly northern stream flow will continue atop the upper ridge across the northern tier of the U.S. This overall pattern will favor bouts of strong to severe thunderstorms within west/northwesterly flow aloft from the northern Plains into portions of the Midwest. However, given subtle forcing mechanisms, this activity will be driven by mesoscale processes/features (MCVs from prior convection, modifying outflow boundaries, etc) that are more uncertain at longer forecast times. As such, predictability is too low for delineating areas at this time. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN/CENTRAL PLAINS TO THE OHIO VALLEY... ...SUMMARY... Strong to severe storms are possible from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...Mid-MS/Lower OH Valley vicinity... Modestly enhanced westerly mid/upper flow will continue on Saturday from the northern Plains to the Great Lakes vicinity. Convection may be ongoing during the morning, perhaps across the Mid-MS Valley or Lake Michigan vicinity in the form of a remnant MCS from the Day 2/Friday period. Meanwhile, a cold front will sag southward across the Upper Midwest toward the Mid-MS valley through early Sunday. Ahead of any ongoing convection and the front, a very moist airmass will be in place and a corridor of strong destabilization is forecast. While upper forcing will remain somewhat nebulous, an MCV or outflow from morning storms could be a focus for severe thunderstorm develop during the afternoon from the IA/IL/MO tri-state area eastward along the moisture/instability gradient into the Ohio Valley. Damaging gusts would be the main hazard with this activity. ...Northern/Central Plains... South/southeasterly low-level flow will transport rich boundary-layer moisture northwest into western NE/SD/ND and perhaps eastern MT along a surface trough. A shortwave ridge over the northern Plains will shift east and weaken by evening, and 30-40 kt mid/upper westerly flow will overspread a narrow corridor of moderate to strong instability. While upper forcing will be nebulous, convergence along the surface trough in the moist low-level upslope flow regime may be sufficient for isolated strong to severe storm development. Vertically veering wind profiles and somewhat elongated hodographs above 3 km suggest supercells will be possible, posing a risk for hail. Steep low-level lapse rates also could support strong outflow winds. ..Leitman.. 07/17/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN/CENTRAL PLAINS TO THE OHIO VALLEY... ...SUMMARY... Strong to severe storms are possible from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...Mid-MS/Lower OH Valley vicinity... Modestly enhanced westerly mid/upper flow will continue on Saturday from the northern Plains to the Great Lakes vicinity. Convection may be ongoing during the morning, perhaps across the Mid-MS Valley or Lake Michigan vicinity in the form of a remnant MCS from the Day 2/Friday period. Meanwhile, a cold front will sag southward across the Upper Midwest toward the Mid-MS valley through early Sunday. Ahead of any ongoing convection and the front, a very moist airmass will be in place and a corridor of strong destabilization is forecast. While upper forcing will remain somewhat nebulous, an MCV or outflow from morning storms could be a focus for severe thunderstorm develop during the afternoon from the IA/IL/MO tri-state area eastward along the moisture/instability gradient into the Ohio Valley. Damaging gusts would be the main hazard with this activity. ...Northern/Central Plains... South/southeasterly low-level flow will transport rich boundary-layer moisture northwest into western NE/SD/ND and perhaps eastern MT along a surface trough. A shortwave ridge over the northern Plains will shift east and weaken by evening, and 30-40 kt mid/upper westerly flow will overspread a narrow corridor of moderate to strong instability. While upper forcing will be nebulous, convergence along the surface trough in the moist low-level upslope flow regime may be sufficient for isolated strong to severe storm development. Vertically veering wind profiles and somewhat elongated hodographs above 3 km suggest supercells will be possible, posing a risk for hail. Steep low-level lapse rates also could support strong outflow winds. ..Leitman.. 07/17/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN/CENTRAL PLAINS TO THE OHIO VALLEY... ...SUMMARY... Strong to severe storms are possible from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...Mid-MS/Lower OH Valley vicinity... Modestly enhanced westerly mid/upper flow will continue on Saturday from the northern Plains to the Great Lakes vicinity. Convection may be ongoing during the morning, perhaps across the Mid-MS Valley or Lake Michigan vicinity in the form of a remnant MCS from the Day 2/Friday period. Meanwhile, a cold front will sag southward across the Upper Midwest toward the Mid-MS valley through early Sunday. Ahead of any ongoing convection and the front, a very moist airmass will be in place and a corridor of strong destabilization is forecast. While upper forcing will remain somewhat nebulous, an MCV or outflow from morning storms could be a focus for severe thunderstorm develop during the afternoon from the IA/IL/MO tri-state area eastward along the moisture/instability gradient into the Ohio Valley. Damaging gusts would be the main hazard with this activity. ...Northern/Central Plains... South/southeasterly low-level flow will transport rich boundary-layer moisture northwest into western NE/SD/ND and perhaps eastern MT along a surface trough. A shortwave ridge over the northern Plains will shift east and weaken by evening, and 30-40 kt mid/upper westerly flow will overspread a narrow corridor of moderate to strong instability. While upper forcing will be nebulous, convergence along the surface trough in the moist low-level upslope flow regime may be sufficient for isolated strong to severe storm development. Vertically veering wind profiles and somewhat elongated hodographs above 3 km suggest supercells will be possible, posing a risk for hail. Steep low-level lapse rates also could support strong outflow winds. ..Leitman.. 07/17/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN/CENTRAL PLAINS TO THE OHIO VALLEY... ...SUMMARY... Strong to severe storms are possible from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...Mid-MS/Lower OH Valley vicinity... Modestly enhanced westerly mid/upper flow will continue on Saturday from the northern Plains to the Great Lakes vicinity. Convection may be ongoing during the morning, perhaps across the Mid-MS Valley or Lake Michigan vicinity in the form of a remnant MCS from the Day 2/Friday period. Meanwhile, a cold front will sag southward across the Upper Midwest toward the Mid-MS valley through early Sunday. Ahead of any ongoing convection and the front, a very moist airmass will be in place and a corridor of strong destabilization is forecast. While upper forcing will remain somewhat nebulous, an MCV or outflow from morning storms could be a focus for severe thunderstorm develop during the afternoon from the IA/IL/MO tri-state area eastward along the moisture/instability gradient into the Ohio Valley. Damaging gusts would be the main hazard with this activity. ...Northern/Central Plains... South/southeasterly low-level flow will transport rich boundary-layer moisture northwest into western NE/SD/ND and perhaps eastern MT along a surface trough. A shortwave ridge over the northern Plains will shift east and weaken by evening, and 30-40 kt mid/upper westerly flow will overspread a narrow corridor of moderate to strong instability. While upper forcing will be nebulous, convergence along the surface trough in the moist low-level upslope flow regime may be sufficient for isolated strong to severe storm development. Vertically veering wind profiles and somewhat elongated hodographs above 3 km suggest supercells will be possible, posing a risk for hail. Steep low-level lapse rates also could support strong outflow winds. ..Leitman.. 07/17/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN/CENTRAL PLAINS TO THE OHIO VALLEY... ...SUMMARY... Strong to severe storms are possible from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...Mid-MS/Lower OH Valley vicinity... Modestly enhanced westerly mid/upper flow will continue on Saturday from the northern Plains to the Great Lakes vicinity. Convection may be ongoing during the morning, perhaps across the Mid-MS Valley or Lake Michigan vicinity in the form of a remnant MCS from the Day 2/Friday period. Meanwhile, a cold front will sag southward across the Upper Midwest toward the Mid-MS valley through early Sunday. Ahead of any ongoing convection and the front, a very moist airmass will be in place and a corridor of strong destabilization is forecast. While upper forcing will remain somewhat nebulous, an MCV or outflow from morning storms could be a focus for severe thunderstorm develop during the afternoon from the IA/IL/MO tri-state area eastward along the moisture/instability gradient into the Ohio Valley. Damaging gusts would be the main hazard with this activity. ...Northern/Central Plains... South/southeasterly low-level flow will transport rich boundary-layer moisture northwest into western NE/SD/ND and perhaps eastern MT along a surface trough. A shortwave ridge over the northern Plains will shift east and weaken by evening, and 30-40 kt mid/upper westerly flow will overspread a narrow corridor of moderate to strong instability. While upper forcing will be nebulous, convergence along the surface trough in the moist low-level upslope flow regime may be sufficient for isolated strong to severe storm development. Vertically veering wind profiles and somewhat elongated hodographs above 3 km suggest supercells will be possible, posing a risk for hail. Steep low-level lapse rates also could support strong outflow winds. ..Leitman.. 07/17/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Thu Jul 17 2025 Valid 181200Z - 191200Z ...Synopsis... A deeper trough will traverse the Pacific Northwest on D2/Friday bringing more widespread Elevated conditions across the areas along and east of the Cascades. Afternoon relative humidity around 10-20 percent will overlap sustained westerly winds at 10-15 mph (locally higher). Some locally Critical conditions may persist for a couple of hours where terrain enhancements favor locally stronger winds in the Cascade Gaps. ...Dry Thunderstorms... The western shortwave will bring forcing for ascent across portions of northern Nevada into southern Idaho and eastern Wyoming. This area remains on the periphery of deeper moisture across the Southwest into the Great Basin. High based convection and very dry boundary layer conditions will favor little to no measurable precipitation with potential for new ignitions from lightning. ..Thornton.. 07/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Thu Jul 17 2025 Valid 181200Z - 191200Z ...Synopsis... A deeper trough will traverse the Pacific Northwest on D2/Friday bringing more widespread Elevated conditions across the areas along and east of the Cascades. Afternoon relative humidity around 10-20 percent will overlap sustained westerly winds at 10-15 mph (locally higher). Some locally Critical conditions may persist for a couple of hours where terrain enhancements favor locally stronger winds in the Cascade Gaps. ...Dry Thunderstorms... The western shortwave will bring forcing for ascent across portions of northern Nevada into southern Idaho and eastern Wyoming. This area remains on the periphery of deeper moisture across the Southwest into the Great Basin. High based convection and very dry boundary layer conditions will favor little to no measurable precipitation with potential for new ignitions from lightning. ..Thornton.. 07/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Thu Jul 17 2025 Valid 181200Z - 191200Z ...Synopsis... A deeper trough will traverse the Pacific Northwest on D2/Friday bringing more widespread Elevated conditions across the areas along and east of the Cascades. Afternoon relative humidity around 10-20 percent will overlap sustained westerly winds at 10-15 mph (locally higher). Some locally Critical conditions may persist for a couple of hours where terrain enhancements favor locally stronger winds in the Cascade Gaps. ...Dry Thunderstorms... The western shortwave will bring forcing for ascent across portions of northern Nevada into southern Idaho and eastern Wyoming. This area remains on the periphery of deeper moisture across the Southwest into the Great Basin. High based convection and very dry boundary layer conditions will favor little to no measurable precipitation with potential for new ignitions from lightning. ..Thornton.. 07/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Thu Jul 17 2025 Valid 181200Z - 191200Z ...Synopsis... A deeper trough will traverse the Pacific Northwest on D2/Friday bringing more widespread Elevated conditions across the areas along and east of the Cascades. Afternoon relative humidity around 10-20 percent will overlap sustained westerly winds at 10-15 mph (locally higher). Some locally Critical conditions may persist for a couple of hours where terrain enhancements favor locally stronger winds in the Cascade Gaps. ...Dry Thunderstorms... The western shortwave will bring forcing for ascent across portions of northern Nevada into southern Idaho and eastern Wyoming. This area remains on the periphery of deeper moisture across the Southwest into the Great Basin. High based convection and very dry boundary layer conditions will favor little to no measurable precipitation with potential for new ignitions from lightning. ..Thornton.. 07/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Thu Jul 17 2025 Valid 171200Z - 181200Z ...Synopsis... A shortwave trough will glance the Pacific Northwest bringing an increase of westerly flow aloft across the Cascades into the Cascade Gaps. As a result, areas of increased westerly downslope flow can be expected along and just east of the Cascades in the Columbia River Basin. Sustained winds 10-15 mph (locally higher in the Cascade Gaps) overlap with afternoon relative humidity reductions to around 10-20 percent. An Elevated delineation was added with this outlook to support this potential. ...Dry Thunderstorms... A closed low off the coast of Baja California will bring moisture northward across portions of the Southwest into the Great Basin. On the fringe of this deeper moisture, isolated dry thunderstorm potential will continue across portions of western Colorado into western Wyoming, Utah, far southern Idaho and eastern Nevada. Here precipitable water values drop to around 0.50" or less with more limited coverage. Some mix of wet/dry thunderstorms will be possible in central Utah and west-central Colorado but storm motions around 15-20 kts will likely yield little measurable precipitation. ..Thornton.. 07/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Thu Jul 17 2025 Valid 171200Z - 181200Z ...Synopsis... A shortwave trough will glance the Pacific Northwest bringing an increase of westerly flow aloft across the Cascades into the Cascade Gaps. As a result, areas of increased westerly downslope flow can be expected along and just east of the Cascades in the Columbia River Basin. Sustained winds 10-15 mph (locally higher in the Cascade Gaps) overlap with afternoon relative humidity reductions to around 10-20 percent. An Elevated delineation was added with this outlook to support this potential. ...Dry Thunderstorms... A closed low off the coast of Baja California will bring moisture northward across portions of the Southwest into the Great Basin. On the fringe of this deeper moisture, isolated dry thunderstorm potential will continue across portions of western Colorado into western Wyoming, Utah, far southern Idaho and eastern Nevada. Here precipitable water values drop to around 0.50" or less with more limited coverage. Some mix of wet/dry thunderstorms will be possible in central Utah and west-central Colorado but storm motions around 15-20 kts will likely yield little measurable precipitation. ..Thornton.. 07/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more