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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Thu Jul 17 2025 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE NORTHERN HIGH PLAINS AND NORTHERN NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a tornado remain possible across northern New England this afternoon. A confined corridor of large hail and severe gusts appears possible from north-central Montana to southwest North Dakota this evening. ...20Z Update... The primary change to the outlook was to add 15 percent wind probabilities across portions of northern into eastern Montana. Here, supercells and/or short line segments should develop amid strong mid/upper flow overspreading the region. Downward momentum transport of this stronger flow aloft may promote efficient severe gust production with the stronger storms. Otherwise, the previous forecast (see below) remains on track, with minor changes made to thunder/severe probabilities to reflect the latest observations and guidance consensus. ..Squitieri.. 07/17/2025 .PREV DISCUSSION... /ISSUED 1125 AM CDT Thu Jul 17 2025/ ...Northeast... Midday visible-satellite imagery shows cloud breaks and surface observations show warming temperatures which imply a destabilizing airmass. A lead, convectively enhanced disturbance evident in radar/satellite imagery, is moving east across southern Quebec, while an upstream larger-scale mid-level trough continues eastward across Ontario and into Quebec later today. A cyclone will develop northeast from eastern Ontario into eastern Quebec while a cold front pushes through the Lower Great Lakes and through much of the Northeast through mid evening. The deep moisture through much of the troposphere and weak lapse rate profiles, which were sampled by the 12 UTC Buffalo and Albany, NY raobs, will undergo moderate destabilization by early to mid afternoon. Although forcing for ascent will favor Quebec into northern New England, scattered thunderstorms will likely develop from Maine southward into southern New England. The greatest potential for some organized storms will favor northern New England where stronger effective shear (30-40 kt) and adequate buoyancy will promote a wind-damage threat with the stronger storms. Forecast sounding over northern Maine show enlarged hodographs for a few hours, which may aid in low-level mesocyclone development and perhaps a risk for a tornado. Lower coverage of severe is forecast farther south where weaker shear will tend to limit storm intensity. The severe activity will likely diminish by the early to mid evening. ...Northern High Plains... Model guidance continues to show a focused corridor of supercell thunderstorm potential from north-central MT to southwest ND, mainly this evening. Water-vapor imagery shows a mid-level shortwave trough rotating southeastward across the southern part of the Canadian Rockies moving towards the northern High Plains. Forecast soundings this afternoon show elongated hodographs amidst modest buoyancy, which would support the development of a supercell or two during the evening. Large hail is the primary hazard with this activity but severe gusts may occur on a localized basis. An isolated hail/wind risk may persist along the ND/SD border vicinity overnight. ...Mid-Atlantic to the Southern High Plains... A surface front draped over the south-central Plains east-northeastward into the mid MS/OH Valleys will focus scattered thunderstorm activity this afternoon. The eastern part of this broader region over the Mid-Atlantic into the OH Valley will be displaced from the mid-level trough over influencing storm activity over the Northeast. A remnant MCV and outflow from overnight storms in the MO/KS/OK vicinity will aid in developing storms and perhaps localized threats for sporadic hail/wind mainly this afternoon. Isolated damaging winds may also occur with thunderstorms that develop east of the central Appalachians this afternoon, even though coverage should be somewhat less. Read more

MD 1698 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR VT...NH...ME
Mesoscale Discussion 1698 NWS Storm Prediction Center Norman OK 1209 PM CDT Thu Jul 17 2025 Areas affected...VT...NH...ME Concerning...Severe potential...Watch likely Valid 171709Z - 171945Z Probability of Watch Issuance...80 percent SUMMARY...Increasing thunderstorm coverage and intensity is anticipated across New England this afternoon and evening. Environmental conditions will support potential severe thunderstorms capable of damaging wind gusts and perhaps a tornado or two. DISCUSSION...Visible satellite imagery continues to show deepening cumulus within the broad warm sector in place across much of New England this afternoon. This deepening is fostered by a combination of strengthening ascent and diurnal destabilization. The airmass across the region is very moist, with dewpoints in the low 70s and PW values around 2 inches. Expectation is for both continued destabilization and persistent forcing for ascent to result in the development of scattered to numerous thunderstorms. Mid-level flow is forecast to strengthen throughout the day as a low-amplitude shortwave trough moves through southern ON and QC. The resulting combination of buoyancy and shear should support transient supercell structures across much of the region, particularly across ME where the mid-level flow will be the strongest. Damaging gusts will be the primary risk with most of these storms. More southerly surface winds are anticipated across ME as well, strengthening the low-level shear and enhancing the tornado potential with any more persistent updrafts. Overall severe coverage will likely be high enough to merit watch issuance. ..Mosier/Smith.. 07/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX...BTV...ALY... LAT...LON 47296949 47456858 47186781 46506780 45526843 42847105 43047321 43997363 45007321 45137173 45337099 45977038 47296949 MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Jul 17 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM IOWA INTO ILLINOIS AND INDIANA... ...SUMMARY... Corridors of strong to severe storms are expected from the northern and central High Plains to the Mid-Mississippi and Lower Ohio Valleys on Saturday. ...IA/IL/IN... Model QPF differences aside, the overarching theme is for a large area of strong instability to develop near a stalled front from southern IA/northern MO into IL and IN Saturday afternoon with mid 70s F dewpoints. This will exist beneath the southern fringe of perhaps 40 kt west/northwest midlevel flow, and the combination of strong instability and favorable deep-layer mean winds will favor corridors of severe storms with damaging winds. Shear may also favor severe hail, and even a few supercells given such large CAPE over IA/IL/IN. The risk area will likely be adjusted in subsequent outlook cycles as the event nears. ...High Plains... Modest westerly midlevel flow of 30-40 kt will exist over the northern High Plains, ahead of a broad upper trough over the Pacific Northwest/northern Rockies. Cool midlevel temperatures will also exist, steepening lapse rates. Strong heating is likely within a surface trough from eastern MT southward across the High Plains, with a ribbon of 1500-2000 J/kg MUCAPE wrapping northwestward around a MN surface high. Cells capable of hail and localized severe gusts will be possible, and a severe MCS is not out of the question overnight into ND as the low-level jet increases. Greater probabilities may be required in later updates. ..Jewell.. 07/17/2025 Read more