Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1251 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z The primary change for this forecast update is an expansion of the isolated dry thunderstorm risk area into eastern WA. Latest ensemble guidance shows a reasonably strong signal for convection developing within the higher terrain of the Cascades before moving east into a drier air mass. While forecast soundings show PWAT values generally near or above 0.75 inches, ensemble QPF output shows low (less than 20%) probability for wetting rainfall. This signal, along with anticipated storm motions near 20 knots and antecedent dry fuel conditions, has increased confidence enough for a northwestward expansion of the dry thunderstorm risk area. A few dry thunderstorms are also possible further south across northern UT, but confidence in the coverage of dry vs wet thunderstorms is more limited based on PWAT and QPF forecasts. A swath of elevated (to perhaps locally critical) wind-driven fire weather conditions remains likely across northern NV. See the previous discussion for additional details. ..Moore.. 08/09/2024 .PREV DISCUSSION... /ISSUED 1240 AM CDT Fri Aug 09 2024/ ...Synopsis... The upper-level tough will continue into the northern Rockies, though it will lose more amplitude on Saturday. A surface trough will deepen in the northern Great Basin beneath a belt of stronger mid-level winds. Elevated fire weather conditions appear probable in portions of northern Nevada into southern Idaho. Surface winds near the trough and the lee of the Sierra will increase to 15-20 mph with RH falling into the teens to perhaps single digits during the afternoon. Additional isolated thunderstorms are possible in central Idaho. Given the stronger flow aloft and dry boundary layer, these storms may produce little rainfall. Some impact on fuels from potential precipitation occurring on Friday could occur. Highlights will be maintained where confidence in storm development is highest and fuels are sufficiently receptive. ...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 1251 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z The primary change for this forecast update is an expansion of the isolated dry thunderstorm risk area into eastern WA. Latest ensemble guidance shows a reasonably strong signal for convection developing within the higher terrain of the Cascades before moving east into a drier air mass. While forecast soundings show PWAT values generally near or above 0.75 inches, ensemble QPF output shows low (less than 20%) probability for wetting rainfall. This signal, along with anticipated storm motions near 20 knots and antecedent dry fuel conditions, has increased confidence enough for a northwestward expansion of the dry thunderstorm risk area. A few dry thunderstorms are also possible further south across northern UT, but confidence in the coverage of dry vs wet thunderstorms is more limited based on PWAT and QPF forecasts. A swath of elevated (to perhaps locally critical) wind-driven fire weather conditions remains likely across northern NV. See the previous discussion for additional details. ..Moore.. 08/09/2024 .PREV DISCUSSION... /ISSUED 1240 AM CDT Fri Aug 09 2024/ ...Synopsis... The upper-level tough will continue into the northern Rockies, though it will lose more amplitude on Saturday. A surface trough will deepen in the northern Great Basin beneath a belt of stronger mid-level winds. Elevated fire weather conditions appear probable in portions of northern Nevada into southern Idaho. Surface winds near the trough and the lee of the Sierra will increase to 15-20 mph with RH falling into the teens to perhaps single digits during the afternoon. Additional isolated thunderstorms are possible in central Idaho. Given the stronger flow aloft and dry boundary layer, these storms may produce little rainfall. Some impact on fuels from potential precipitation occurring on Friday could occur. Highlights will be maintained where confidence in storm development is highest and fuels are sufficiently receptive. ...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 1251 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z The primary change for this forecast update is an expansion of the isolated dry thunderstorm risk area into eastern WA. Latest ensemble guidance shows a reasonably strong signal for convection developing within the higher terrain of the Cascades before moving east into a drier air mass. While forecast soundings show PWAT values generally near or above 0.75 inches, ensemble QPF output shows low (less than 20%) probability for wetting rainfall. This signal, along with anticipated storm motions near 20 knots and antecedent dry fuel conditions, has increased confidence enough for a northwestward expansion of the dry thunderstorm risk area. A few dry thunderstorms are also possible further south across northern UT, but confidence in the coverage of dry vs wet thunderstorms is more limited based on PWAT and QPF forecasts. A swath of elevated (to perhaps locally critical) wind-driven fire weather conditions remains likely across northern NV. See the previous discussion for additional details. ..Moore.. 08/09/2024 .PREV DISCUSSION... /ISSUED 1240 AM CDT Fri Aug 09 2024/ ...Synopsis... The upper-level tough will continue into the northern Rockies, though it will lose more amplitude on Saturday. A surface trough will deepen in the northern Great Basin beneath a belt of stronger mid-level winds. Elevated fire weather conditions appear probable in portions of northern Nevada into southern Idaho. Surface winds near the trough and the lee of the Sierra will increase to 15-20 mph with RH falling into the teens to perhaps single digits during the afternoon. Additional isolated thunderstorms are possible in central Idaho. Given the stronger flow aloft and dry boundary layer, these storms may produce little rainfall. Some impact on fuels from potential precipitation occurring on Friday could occur. Highlights will be maintained where confidence in storm development is highest and fuels are sufficiently receptive. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0617 Status Updates
STATUS FOR WATCH 0617 HAS NOT BEEN ISSUED YET Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms, capable of damaging gusts and perhaps hail, are possible during the afternoon into early evening over parts of the central and southern High Plains. ...Synopsis... Upper cyclone centered over northeast Ontario Saturday morning is forecast to progress gradually eastward/east-northeastward throughout the day, ending the period centered over the central Ontario/Quebec border vicinity. Several shortwave troughs will rotate through the enhanced mid-level flow within the base of this cyclone, which stretches cyclonically from the Upper Midwest across the Upper Great Lakes/OH Valley and into the Northeast/St. Lawrence Valley. A cold front is expected to extend from ME southward off the coast of southern New England before then arcing back more southwestward through the Carolinas and GA into the central Gulf of Mexico. The series of shortwave troughs rotating around the cyclone will help reinforce the continental airmass cover much of the eastern CONUS, with little change in the location of the cold front from the Carolinas into the central Gulf. Isolated thunderstorms are anticipated east/southeast of this front, but weak shear should keep the severe potential low. Farther west, low-amplitude ridging will remain centered over the Far West TX/southeast NM vicinity, with westerly flow aloft extending throughout the northern periphery of this ridging from OR/northern CA through the central Plains. This westerly flow aloft will help support a sharpening lee surface trough and resulting low-level moisture advection across the High Plains. ...Central/Southern High Plains. Tightening surface pressure gradient between this troughing and high pressure over the central/southern MO Valley will support low-level southerly flow and associated moisture return across the southern/central High Plains. Afternoon thunderstorm development is anticipated across the Rockies, with the westerly flow aloft then taking these storms away from the higher terrain into the High Plains. Deep boundary-layer mixing is anticipated, but the anticipated low-level moisture advection should still keep at least modest moisture in place. Current expectation is for afternoon dewpoints to range from the low 50s across eastern WY to the low 60s in the northeast NM/southeast CO/southwest KS/western OK Panhandle vicinity. This low-level moisture will help support moderate buoyancy, with MLCAPE from 500 J/kg over eastern WY to 1500 J/kg in southeast CO. Low-level southeasterlies veering to westerly aloft will also support moderate vertical shear, even though overall magnitude of both the surface winds and the westerly flow aloft is modest. These environmental conditions could support persistent multicells and perhaps brief supercells, with isolated severe gusts and hail. ..Mosier.. 08/09/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Fri Aug 09 2024 Valid 091630Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN PENNSYLVANIA...EASTERN NEW YORK...AND NEW JERSEY...AND INTO WESTERN NEW ENGLAND... ...SUMMARY... A couple of tornadoes will be possible today from parts of the Mid-Atlantic states northward across portions of New England. A few strong wind gusts will also be possible across this region, along with parts of the southern High Plains, and southern Wyoming. ...Portions of the Mid-Atlantic and New England... As the center of P.T.C. Debby -- now over south-central New York -- continues moving north-northeastward across New York today, and then into Quebec/across the St. Lawrence Valley this evening and tonight, very strong low-level shear will continue to spread northward across eastern New York and much of New England. While northward destabilization will be hindered by a lack of appreciable daytime heating due to widespread cloud cover, a very moist boundary layer (dewpoints in the upper 60s to low 70s) spreading northward toward the Canadian border will support at least neutrally buoyant profiles across most of New England this evening and tonight. As such, low (2%) tornado probability is being expanded northward/northeastward in this update, to include the remainder of northern Vermont and northern New Hampshire, and much of Maine, to cover the potential for a brief tornadic spin-up after dark. Otherwise, greatest potential for a couple of tornadoes will exist this afternoon and into this evening from eastern Pennsylvania/eastern New York into parts of New Jersey, and across the Hudson and Champlain Valleys into western Vermont, western Massachusetts, and western Connecticut. ...Southern High Plains... Afternoon storm development is expected across the Raton Mesa vicinity of northeastern New Mexico, aided by afternoon heating/destabilization, and the eastward advance of a mid-level vort max across southern Colorado. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts as convection crosses the Oklahoma and northern Texas Panhandle area. ...Southern Wyoming... Daytime heating/modest destabilization across the Intermountain West will support development of isolated to scattered afternoon and evening thunderstorms. With a belt of moderate (30 to 40 kt) northwesterly flow across the Wyoming vicinity, some storm organization will be possible. Some CAMs suggest eventual upscale growth into a loosely organized cluster by this evening, moving east-southeastward toward southeastern portions of the state. Resulting potential for a few stronger wind gusts with this activity warrants inclusion of 5% wind probability/MRGL risk area. ..Goss/Weinman.. 08/09/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Fri Aug 09 2024 Valid 091630Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN PENNSYLVANIA...EASTERN NEW YORK...AND NEW JERSEY...AND INTO WESTERN NEW ENGLAND... ...SUMMARY... A couple of tornadoes will be possible today from parts of the Mid-Atlantic states northward across portions of New England. A few strong wind gusts will also be possible across this region, along with parts of the southern High Plains, and southern Wyoming. ...Portions of the Mid-Atlantic and New England... As the center of P.T.C. Debby -- now over south-central New York -- continues moving north-northeastward across New York today, and then into Quebec/across the St. Lawrence Valley this evening and tonight, very strong low-level shear will continue to spread northward across eastern New York and much of New England. While northward destabilization will be hindered by a lack of appreciable daytime heating due to widespread cloud cover, a very moist boundary layer (dewpoints in the upper 60s to low 70s) spreading northward toward the Canadian border will support at least neutrally buoyant profiles across most of New England this evening and tonight. As such, low (2%) tornado probability is being expanded northward/northeastward in this update, to include the remainder of northern Vermont and northern New Hampshire, and much of Maine, to cover the potential for a brief tornadic spin-up after dark. Otherwise, greatest potential for a couple of tornadoes will exist this afternoon and into this evening from eastern Pennsylvania/eastern New York into parts of New Jersey, and across the Hudson and Champlain Valleys into western Vermont, western Massachusetts, and western Connecticut. ...Southern High Plains... Afternoon storm development is expected across the Raton Mesa vicinity of northeastern New Mexico, aided by afternoon heating/destabilization, and the eastward advance of a mid-level vort max across southern Colorado. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts as convection crosses the Oklahoma and northern Texas Panhandle area. ...Southern Wyoming... Daytime heating/modest destabilization across the Intermountain West will support development of isolated to scattered afternoon and evening thunderstorms. With a belt of moderate (30 to 40 kt) northwesterly flow across the Wyoming vicinity, some storm organization will be possible. Some CAMs suggest eventual upscale growth into a loosely organized cluster by this evening, moving east-southeastward toward southeastern portions of the state. Resulting potential for a few stronger wind gusts with this activity warrants inclusion of 5% wind probability/MRGL risk area. ..Goss/Weinman.. 08/09/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Fri Aug 09 2024 Valid 091630Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN PENNSYLVANIA...EASTERN NEW YORK...AND NEW JERSEY...AND INTO WESTERN NEW ENGLAND... ...SUMMARY... A couple of tornadoes will be possible today from parts of the Mid-Atlantic states northward across portions of New England. A few strong wind gusts will also be possible across this region, along with parts of the southern High Plains, and southern Wyoming. ...Portions of the Mid-Atlantic and New England... As the center of P.T.C. Debby -- now over south-central New York -- continues moving north-northeastward across New York today, and then into Quebec/across the St. Lawrence Valley this evening and tonight, very strong low-level shear will continue to spread northward across eastern New York and much of New England. While northward destabilization will be hindered by a lack of appreciable daytime heating due to widespread cloud cover, a very moist boundary layer (dewpoints in the upper 60s to low 70s) spreading northward toward the Canadian border will support at least neutrally buoyant profiles across most of New England this evening and tonight. As such, low (2%) tornado probability is being expanded northward/northeastward in this update, to include the remainder of northern Vermont and northern New Hampshire, and much of Maine, to cover the potential for a brief tornadic spin-up after dark. Otherwise, greatest potential for a couple of tornadoes will exist this afternoon and into this evening from eastern Pennsylvania/eastern New York into parts of New Jersey, and across the Hudson and Champlain Valleys into western Vermont, western Massachusetts, and western Connecticut. ...Southern High Plains... Afternoon storm development is expected across the Raton Mesa vicinity of northeastern New Mexico, aided by afternoon heating/destabilization, and the eastward advance of a mid-level vort max across southern Colorado. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts as convection crosses the Oklahoma and northern Texas Panhandle area. ...Southern Wyoming... Daytime heating/modest destabilization across the Intermountain West will support development of isolated to scattered afternoon and evening thunderstorms. With a belt of moderate (30 to 40 kt) northwesterly flow across the Wyoming vicinity, some storm organization will be possible. Some CAMs suggest eventual upscale growth into a loosely organized cluster by this evening, moving east-southeastward toward southeastern portions of the state. Resulting potential for a few stronger wind gusts with this activity warrants inclusion of 5% wind probability/MRGL risk area. ..Goss/Weinman.. 08/09/2024 Read more