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MD 2078 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR SOUTHEAST COLORADO INTO EASTERN NEW MEXICO
Mesoscale Discussion 2078 NWS Storm Prediction Center Norman OK 0125 PM CDT Tue Sep 17 2024 Areas affected...Southeast Colorado into eastern New Mexico Concerning...Severe potential...Watch likely Valid 171825Z - 172030Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms developing across central to northern New Mexico are expected to increase in coverage and intensity through the afternoon hours. Trends are being monitored, and watch issuance is anticipated soon. DISCUSSION...Over the past 30-60 minutes, initially weak convection across central to northern NM has shown signs of steady intensification via increased lightning activity and steadily cooling cloud-top temperatures. This uptick is largely being driven by diurnal destabilization as temperatures warm into the low to mid 80s, which is eroding MLCIN and bolstering MLCAPE to around 1000 J/kg across northern NM. Further intensification downstream across northeast/eastern NM and southeast CO appears likely as storms migrate into a relatively more moist/buoyant environment where southerly low-level winds are maintaining dewpoints in the upper 50s to low 60s. 30-40 knot mid-level flow should spread east in tandem with the deepening convection, which should provide adequate deep-layer shear for organized convection. Based on recent radar trends, a mix of semi-discrete clusters and supercells appears likely with an attendant risk of large hail (most likely between 1.0 to 1.5 inches in diameter) and strong to severe winds. Watch issuance will likely be needed soon as convection continues to intensify and poses a greater severe threat. ..Moore/Gleason.. 09/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AMA...PUB...ABQ... LAT...LON 33400537 34760565 35270600 35800617 36550610 37160577 37590516 37890430 38000351 37650305 36910283 36010290 35080304 34410318 33980341 33580373 33310498 33400537 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Sep 17 2024 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...20Z Update... Relatively minor adjustments were made to the wind probabilities across parts of the southern Rockies/High Plains where convection has increased and shown some signs of linear organization. A significant wind gust or two is possible as this activity tracks north-northeastward into better moisture. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 09/17/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Sep 17 2024/ ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0242 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...20z Update... Model and observational trends continue to suggest widespread wetting rainfall is likely over much of the central and northern High Plains late D1/Tuesday into early D2/Wednesday. Thus, despite strong winds and pockets of lower humidity, the availability of dry fuels appears limited. See the previous discussion for more details. ..Lyons.. 09/17/2024 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 17 2024/ ...Synopsis... Strong deep-layer southwesterly flow will overspread the Dakotas, within the base of a negatively tilted midlevel trough/low moving northeastward across the northern High Plains. A tight pressure gradient peripheral to a related surface cyclone over eastern MT will promote strong post-frontal surface winds across western SD. While these winds and around 20 percent RH would typically warrant fire-weather highlights, substantial precipitation over the past week, and additional expected rainfall on Day 1/Tuesday, limit confidence in fuel receptiveness. ...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 0242 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...20z Update... Model and observational trends continue to suggest widespread wetting rainfall is likely over much of the central and northern High Plains late D1/Tuesday into early D2/Wednesday. Thus, despite strong winds and pockets of lower humidity, the availability of dry fuels appears limited. See the previous discussion for more details. ..Lyons.. 09/17/2024 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 17 2024/ ...Synopsis... Strong deep-layer southwesterly flow will overspread the Dakotas, within the base of a negatively tilted midlevel trough/low moving northeastward across the northern High Plains. A tight pressure gradient peripheral to a related surface cyclone over eastern MT will promote strong post-frontal surface winds across western SD. While these winds and around 20 percent RH would typically warrant fire-weather highlights, substantial precipitation over the past week, and additional expected rainfall on Day 1/Tuesday, limit confidence in fuel receptiveness. ...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 0242 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...20z Update... Model and observational trends continue to suggest widespread wetting rainfall is likely over much of the central and northern High Plains late D1/Tuesday into early D2/Wednesday. Thus, despite strong winds and pockets of lower humidity, the availability of dry fuels appears limited. See the previous discussion for more details. ..Lyons.. 09/17/2024 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 17 2024/ ...Synopsis... Strong deep-layer southwesterly flow will overspread the Dakotas, within the base of a negatively tilted midlevel trough/low moving northeastward across the northern High Plains. A tight pressure gradient peripheral to a related surface cyclone over eastern MT will promote strong post-frontal surface winds across western SD. While these winds and around 20 percent RH would typically warrant fire-weather highlights, substantial precipitation over the past week, and additional expected rainfall on Day 1/Tuesday, limit confidence in fuel receptiveness. ...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 0242 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...20z Update... Model and observational trends continue to suggest widespread wetting rainfall is likely over much of the central and northern High Plains late D1/Tuesday into early D2/Wednesday. Thus, despite strong winds and pockets of lower humidity, the availability of dry fuels appears limited. See the previous discussion for more details. ..Lyons.. 09/17/2024 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 17 2024/ ...Synopsis... Strong deep-layer southwesterly flow will overspread the Dakotas, within the base of a negatively tilted midlevel trough/low moving northeastward across the northern High Plains. A tight pressure gradient peripheral to a related surface cyclone over eastern MT will promote strong post-frontal surface winds across western SD. While these winds and around 20 percent RH would typically warrant fire-weather highlights, substantial precipitation over the past week, and additional expected rainfall on Day 1/Tuesday, limit confidence in fuel receptiveness. ...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 0242 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...20z Update... Model and observational trends continue to suggest widespread wetting rainfall is likely over much of the central and northern High Plains late D1/Tuesday into early D2/Wednesday. Thus, despite strong winds and pockets of lower humidity, the availability of dry fuels appears limited. See the previous discussion for more details. ..Lyons.. 09/17/2024 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 17 2024/ ...Synopsis... Strong deep-layer southwesterly flow will overspread the Dakotas, within the base of a negatively tilted midlevel trough/low moving northeastward across the northern High Plains. A tight pressure gradient peripheral to a related surface cyclone over eastern MT will promote strong post-frontal surface winds across western SD. While these winds and around 20 percent RH would typically warrant fire-weather highlights, substantial precipitation over the past week, and additional expected rainfall on Day 1/Tuesday, limit confidence in fuel receptiveness. ...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 0242 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...20z Update... Model and observational trends continue to suggest widespread wetting rainfall is likely over much of the central and northern High Plains late D1/Tuesday into early D2/Wednesday. Thus, despite strong winds and pockets of lower humidity, the availability of dry fuels appears limited. See the previous discussion for more details. ..Lyons.. 09/17/2024 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 17 2024/ ...Synopsis... Strong deep-layer southwesterly flow will overspread the Dakotas, within the base of a negatively tilted midlevel trough/low moving northeastward across the northern High Plains. A tight pressure gradient peripheral to a related surface cyclone over eastern MT will promote strong post-frontal surface winds across western SD. While these winds and around 20 percent RH would typically warrant fire-weather highlights, substantial precipitation over the past week, and additional expected rainfall on Day 1/Tuesday, limit confidence in fuel receptiveness. ...Please see www.spc.noaa.gov/fire for graphic product... Read more