Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0143 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... Similar conditions present over the Interior West today should also occur again for tomorrow (Friday). A mid-level trough will remain in place over the Plains/Mississippi Valley areas as a mid-level anticyclone meanders along the West Coast. Widespread dry conditions (i.e. 10-20 percent RH) should be prevalent by afternoon from the Pacific Northwest to the Desert Southwest. Still, sustained surface winds should remain below 15 mph on the large scale, though terrain-favoring areas may experience localized Elevated conditions. ..Squitieri.. 07/04/2024 ...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 0143 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... Similar conditions present over the Interior West today should also occur again for tomorrow (Friday). A mid-level trough will remain in place over the Plains/Mississippi Valley areas as a mid-level anticyclone meanders along the West Coast. Widespread dry conditions (i.e. 10-20 percent RH) should be prevalent by afternoon from the Pacific Northwest to the Desert Southwest. Still, sustained surface winds should remain below 15 mph on the large scale, though terrain-favoring areas may experience localized Elevated conditions. ..Squitieri.. 07/04/2024 ...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 0143 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... Similar conditions present over the Interior West today should also occur again for tomorrow (Friday). A mid-level trough will remain in place over the Plains/Mississippi Valley areas as a mid-level anticyclone meanders along the West Coast. Widespread dry conditions (i.e. 10-20 percent RH) should be prevalent by afternoon from the Pacific Northwest to the Desert Southwest. Still, sustained surface winds should remain below 15 mph on the large scale, though terrain-favoring areas may experience localized Elevated conditions. ..Squitieri.. 07/04/2024 ...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 0143 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... Similar conditions present over the Interior West today should also occur again for tomorrow (Friday). A mid-level trough will remain in place over the Plains/Mississippi Valley areas as a mid-level anticyclone meanders along the West Coast. Widespread dry conditions (i.e. 10-20 percent RH) should be prevalent by afternoon from the Pacific Northwest to the Desert Southwest. Still, sustained surface winds should remain below 15 mph on the large scale, though terrain-favoring areas may experience localized Elevated conditions. ..Squitieri.. 07/04/2024 ...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 0143 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... Similar conditions present over the Interior West today should also occur again for tomorrow (Friday). A mid-level trough will remain in place over the Plains/Mississippi Valley areas as a mid-level anticyclone meanders along the West Coast. Widespread dry conditions (i.e. 10-20 percent RH) should be prevalent by afternoon from the Pacific Northwest to the Desert Southwest. Still, sustained surface winds should remain below 15 mph on the large scale, though terrain-favoring areas may experience localized Elevated conditions. ..Squitieri.. 07/04/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...Synopsis... A mid-level trough will move across the central U.S. as upper ridging builds back over the Interior West today. Stronger deep-layer northwesterly flow will overspread the West Coast, that with boundary-layer heating/mixing, may reach the surface in terrain favoring locations. Once such place is the San Joaquin Valley area in central California, where 15 mph sustained northwesterly surface winds may coincide with 10-15 percent RH by afternoon peak heating, warranting the continuation of Elevated highlights. Dry and occasionally breezy conditions may also be expected across much of the Great Basin into the central Rockies this afternoon. Though widespread 10-15 percent RH should be common, stronger surface winds are not likely to be particularly widespread. Nonetheless, locally windy conditions (and associated wildfire-spread potential) are possible in terrain favoring areas. ..Squitieri.. 07/04/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...Synopsis... A mid-level trough will move across the central U.S. as upper ridging builds back over the Interior West today. Stronger deep-layer northwesterly flow will overspread the West Coast, that with boundary-layer heating/mixing, may reach the surface in terrain favoring locations. Once such place is the San Joaquin Valley area in central California, where 15 mph sustained northwesterly surface winds may coincide with 10-15 percent RH by afternoon peak heating, warranting the continuation of Elevated highlights. Dry and occasionally breezy conditions may also be expected across much of the Great Basin into the central Rockies this afternoon. Though widespread 10-15 percent RH should be common, stronger surface winds are not likely to be particularly widespread. Nonetheless, locally windy conditions (and associated wildfire-spread potential) are possible in terrain favoring areas. ..Squitieri.. 07/04/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...Synopsis... A mid-level trough will move across the central U.S. as upper ridging builds back over the Interior West today. Stronger deep-layer northwesterly flow will overspread the West Coast, that with boundary-layer heating/mixing, may reach the surface in terrain favoring locations. Once such place is the San Joaquin Valley area in central California, where 15 mph sustained northwesterly surface winds may coincide with 10-15 percent RH by afternoon peak heating, warranting the continuation of Elevated highlights. Dry and occasionally breezy conditions may also be expected across much of the Great Basin into the central Rockies this afternoon. Though widespread 10-15 percent RH should be common, stronger surface winds are not likely to be particularly widespread. Nonetheless, locally windy conditions (and associated wildfire-spread potential) are possible in terrain favoring areas. ..Squitieri.. 07/04/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...Synopsis... A mid-level trough will move across the central U.S. as upper ridging builds back over the Interior West today. Stronger deep-layer northwesterly flow will overspread the West Coast, that with boundary-layer heating/mixing, may reach the surface in terrain favoring locations. Once such place is the San Joaquin Valley area in central California, where 15 mph sustained northwesterly surface winds may coincide with 10-15 percent RH by afternoon peak heating, warranting the continuation of Elevated highlights. Dry and occasionally breezy conditions may also be expected across much of the Great Basin into the central Rockies this afternoon. Though widespread 10-15 percent RH should be common, stronger surface winds are not likely to be particularly widespread. Nonetheless, locally windy conditions (and associated wildfire-spread potential) are possible in terrain favoring areas. ..Squitieri.. 07/04/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...Synopsis... A mid-level trough will move across the central U.S. as upper ridging builds back over the Interior West today. Stronger deep-layer northwesterly flow will overspread the West Coast, that with boundary-layer heating/mixing, may reach the surface in terrain favoring locations. Once such place is the San Joaquin Valley area in central California, where 15 mph sustained northwesterly surface winds may coincide with 10-15 percent RH by afternoon peak heating, warranting the continuation of Elevated highlights. Dry and occasionally breezy conditions may also be expected across much of the Great Basin into the central Rockies this afternoon. Though widespread 10-15 percent RH should be common, stronger surface winds are not likely to be particularly widespread. Nonetheless, locally windy conditions (and associated wildfire-spread potential) are possible in terrain favoring areas. ..Squitieri.. 07/04/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Marginally severe storms are most likely across parts of the upper Ohio Valley on Friday. ...Synopsis... An upper-level low in the Upper Midwest will continue eastward on Saturday before becoming more of an open wave by Saturday morning. A potent mid-level jet is anticipated across parts of the upper Ohio Valley during the afternoon. At the surface, a low in the Lake Michigan/Lower Michigan vicinity will also track eastward, with a attendant cold front moving through the Ohio Valley by mid/late afternoon and evening. ...Upper Ohio Valley... Uncertainty remains relatively high in the degree of surface-based destabilization that will occur by the afternoon. Morning showers/thunderstorms are possible within a weak warm advection regime. Further, cloud cover from the remnants of convection moving through the lower Ohio Valley on Thursday night may also have an impact. Given the moist airmass (low 70s F dewpoints), broken cloud cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000 J/kg in the southernmost areas). Effective shear will range from 35 kts to the south and increase to around 50 kts to the north. On the lower end of destabilization, only isolated cells would be likely. Should greater surface heating occur, a linear segment or two could develop. Damaging winds and small hail are possible with the strongest storms. ...Blue Ridge... Strong heating is expected within a high PWAT airmass. Temperatures are expected to reach the mid 90s F. Though mid-level heights will remain neutral, convection is probable within the terrain. Weak deep-layer shear and similarly weak anvil-level flow should keep storm organization minimal. Confidence in more than isolated wet microbursts is too low for highlights. ..Wendt.. 07/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Marginally severe storms are most likely across parts of the upper Ohio Valley on Friday. ...Synopsis... An upper-level low in the Upper Midwest will continue eastward on Saturday before becoming more of an open wave by Saturday morning. A potent mid-level jet is anticipated across parts of the upper Ohio Valley during the afternoon. At the surface, a low in the Lake Michigan/Lower Michigan vicinity will also track eastward, with a attendant cold front moving through the Ohio Valley by mid/late afternoon and evening. ...Upper Ohio Valley... Uncertainty remains relatively high in the degree of surface-based destabilization that will occur by the afternoon. Morning showers/thunderstorms are possible within a weak warm advection regime. Further, cloud cover from the remnants of convection moving through the lower Ohio Valley on Thursday night may also have an impact. Given the moist airmass (low 70s F dewpoints), broken cloud cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000 J/kg in the southernmost areas). Effective shear will range from 35 kts to the south and increase to around 50 kts to the north. On the lower end of destabilization, only isolated cells would be likely. Should greater surface heating occur, a linear segment or two could develop. Damaging winds and small hail are possible with the strongest storms. ...Blue Ridge... Strong heating is expected within a high PWAT airmass. Temperatures are expected to reach the mid 90s F. Though mid-level heights will remain neutral, convection is probable within the terrain. Weak deep-layer shear and similarly weak anvil-level flow should keep storm organization minimal. Confidence in more than isolated wet microbursts is too low for highlights. ..Wendt.. 07/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Marginally severe storms are most likely across parts of the upper Ohio Valley on Friday. ...Synopsis... An upper-level low in the Upper Midwest will continue eastward on Saturday before becoming more of an open wave by Saturday morning. A potent mid-level jet is anticipated across parts of the upper Ohio Valley during the afternoon. At the surface, a low in the Lake Michigan/Lower Michigan vicinity will also track eastward, with a attendant cold front moving through the Ohio Valley by mid/late afternoon and evening. ...Upper Ohio Valley... Uncertainty remains relatively high in the degree of surface-based destabilization that will occur by the afternoon. Morning showers/thunderstorms are possible within a weak warm advection regime. Further, cloud cover from the remnants of convection moving through the lower Ohio Valley on Thursday night may also have an impact. Given the moist airmass (low 70s F dewpoints), broken cloud cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000 J/kg in the southernmost areas). Effective shear will range from 35 kts to the south and increase to around 50 kts to the north. On the lower end of destabilization, only isolated cells would be likely. Should greater surface heating occur, a linear segment or two could develop. Damaging winds and small hail are possible with the strongest storms. ...Blue Ridge... Strong heating is expected within a high PWAT airmass. Temperatures are expected to reach the mid 90s F. Though mid-level heights will remain neutral, convection is probable within the terrain. Weak deep-layer shear and similarly weak anvil-level flow should keep storm organization minimal. Confidence in more than isolated wet microbursts is too low for highlights. ..Wendt.. 07/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Marginally severe storms are most likely across parts of the upper Ohio Valley on Friday. ...Synopsis... An upper-level low in the Upper Midwest will continue eastward on Saturday before becoming more of an open wave by Saturday morning. A potent mid-level jet is anticipated across parts of the upper Ohio Valley during the afternoon. At the surface, a low in the Lake Michigan/Lower Michigan vicinity will also track eastward, with a attendant cold front moving through the Ohio Valley by mid/late afternoon and evening. ...Upper Ohio Valley... Uncertainty remains relatively high in the degree of surface-based destabilization that will occur by the afternoon. Morning showers/thunderstorms are possible within a weak warm advection regime. Further, cloud cover from the remnants of convection moving through the lower Ohio Valley on Thursday night may also have an impact. Given the moist airmass (low 70s F dewpoints), broken cloud cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000 J/kg in the southernmost areas). Effective shear will range from 35 kts to the south and increase to around 50 kts to the north. On the lower end of destabilization, only isolated cells would be likely. Should greater surface heating occur, a linear segment or two could develop. Damaging winds and small hail are possible with the strongest storms. ...Blue Ridge... Strong heating is expected within a high PWAT airmass. Temperatures are expected to reach the mid 90s F. Though mid-level heights will remain neutral, convection is probable within the terrain. Weak deep-layer shear and similarly weak anvil-level flow should keep storm organization minimal. Confidence in more than isolated wet microbursts is too low for highlights. ..Wendt.. 07/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Marginally severe storms are most likely across parts of the upper Ohio Valley on Friday. ...Synopsis... An upper-level low in the Upper Midwest will continue eastward on Saturday before becoming more of an open wave by Saturday morning. A potent mid-level jet is anticipated across parts of the upper Ohio Valley during the afternoon. At the surface, a low in the Lake Michigan/Lower Michigan vicinity will also track eastward, with a attendant cold front moving through the Ohio Valley by mid/late afternoon and evening. ...Upper Ohio Valley... Uncertainty remains relatively high in the degree of surface-based destabilization that will occur by the afternoon. Morning showers/thunderstorms are possible within a weak warm advection regime. Further, cloud cover from the remnants of convection moving through the lower Ohio Valley on Thursday night may also have an impact. Given the moist airmass (low 70s F dewpoints), broken cloud cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000 J/kg in the southernmost areas). Effective shear will range from 35 kts to the south and increase to around 50 kts to the north. On the lower end of destabilization, only isolated cells would be likely. Should greater surface heating occur, a linear segment or two could develop. Damaging winds and small hail are possible with the strongest storms. ...Blue Ridge... Strong heating is expected within a high PWAT airmass. Temperatures are expected to reach the mid 90s F. Though mid-level heights will remain neutral, convection is probable within the terrain. Weak deep-layer shear and similarly weak anvil-level flow should keep storm organization minimal. Confidence in more than isolated wet microbursts is too low for highlights. ..Wendt.. 07/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Jul 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Marginally severe storms are most likely across parts of the upper Ohio Valley on Friday. ...Synopsis... An upper-level low in the Upper Midwest will continue eastward on Saturday before becoming more of an open wave by Saturday morning. A potent mid-level jet is anticipated across parts of the upper Ohio Valley during the afternoon. At the surface, a low in the Lake Michigan/Lower Michigan vicinity will also track eastward, with a attendant cold front moving through the Ohio Valley by mid/late afternoon and evening. ...Upper Ohio Valley... Uncertainty remains relatively high in the degree of surface-based destabilization that will occur by the afternoon. Morning showers/thunderstorms are possible within a weak warm advection regime. Further, cloud cover from the remnants of convection moving through the lower Ohio Valley on Thursday night may also have an impact. Given the moist airmass (low 70s F dewpoints), broken cloud cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000 J/kg in the southernmost areas). Effective shear will range from 35 kts to the south and increase to around 50 kts to the north. On the lower end of destabilization, only isolated cells would be likely. Should greater surface heating occur, a linear segment or two could develop. Damaging winds and small hail are possible with the strongest storms. ...Blue Ridge... Strong heating is expected within a high PWAT airmass. Temperatures are expected to reach the mid 90s F. Though mid-level heights will remain neutral, convection is probable within the terrain. Weak deep-layer shear and similarly weak anvil-level flow should keep storm organization minimal. Confidence in more than isolated wet microbursts is too low for highlights. ..Wendt.. 07/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MISSISSIPPI VALLEY AND FROM THE MISSOURI OZARKS INTO THE SOUTHERN PLAINS... ...SUMMARY... Severe thunderstorms will be possible across parts of the Upper Mississippi Valley, Ozarks, and southern Plains. ...Discussion... Seasonally strong upper trough is shifting east across the northern Plains early this morning. This feature is forecast to advance toward the middle MO Valley by late afternoon as 500mb, 60kt speed max translates across southeast NE into IA. Left exit region of this speed max will spread across the upper MS Valley along with a corridor of modest 12hr mid-level height falls. Latest model guidance suggests a weak surface low will develop and track along the MN/IA border into southwest WI by late evening. This corridor appears favorable for robust convective development as boundary layer warms and convective temperatures are breached, likely by midday, as readings warm through the upper 70s-80F. Forecast soundings exhibit veering wind profiles with height, and some supercell potential exists within this zone of focused ascent. Large hail and locally damaging winds are the primary concerns. Farther south, an expansive corridor of convection has evolved over the central Plains early this morning. Upscale growth may continue for the next few hours, and a long-lived MCS should propagate across eastern KS into MO by sunrise. While this complex may not be particularly severe at daybreak, a long-lived MCS, or its remnants, will advance downstream into the OH Valley as modest mid-level flow will extend along a corridor from MO into southern OH. Models are not too aggressive in steepening low-level lapse rates east of the MS River later today, but some surface heating is expected to contribute to increased buoyancy that will likely contribute to new robust updrafts developing along the MCS outflow/differential- heating zone. Will maintain MRGL risk across this region, although somewhat higher severe probabilities may be warranted, especially across KY along the southern flank of the forward-propagating MCS. Later in the day, very strong surface heating across the southern Plains will result in steep surface-3km lapse rates from northwest TX, across central into northeast OK. As the northern Plains trough shifts east, mid-level flow will begin to turn more westerly across northern OK, and 500mb speeds will increase to 25-40kt north of I-40. Convective temperatures will be breached by 22z, just ahead of the surface front, and scattered thunderstorms should easily develop along the wind shift. PWs will be very high across this region with values in excess of 2 inches. With temp/dew point spreads around 30F, there is increasing confidence that the most robust convection should generate severe downdrafts. A fairly concentrated corridor of convection should evolve downstream into the MO Ozarks by early evening. ..Darrow/Squitieri.. 07/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MISSISSIPPI VALLEY AND FROM THE MISSOURI OZARKS INTO THE SOUTHERN PLAINS... ...SUMMARY... Severe thunderstorms will be possible across parts of the Upper Mississippi Valley, Ozarks, and southern Plains. ...Discussion... Seasonally strong upper trough is shifting east across the northern Plains early this morning. This feature is forecast to advance toward the middle MO Valley by late afternoon as 500mb, 60kt speed max translates across southeast NE into IA. Left exit region of this speed max will spread across the upper MS Valley along with a corridor of modest 12hr mid-level height falls. Latest model guidance suggests a weak surface low will develop and track along the MN/IA border into southwest WI by late evening. This corridor appears favorable for robust convective development as boundary layer warms and convective temperatures are breached, likely by midday, as readings warm through the upper 70s-80F. Forecast soundings exhibit veering wind profiles with height, and some supercell potential exists within this zone of focused ascent. Large hail and locally damaging winds are the primary concerns. Farther south, an expansive corridor of convection has evolved over the central Plains early this morning. Upscale growth may continue for the next few hours, and a long-lived MCS should propagate across eastern KS into MO by sunrise. While this complex may not be particularly severe at daybreak, a long-lived MCS, or its remnants, will advance downstream into the OH Valley as modest mid-level flow will extend along a corridor from MO into southern OH. Models are not too aggressive in steepening low-level lapse rates east of the MS River later today, but some surface heating is expected to contribute to increased buoyancy that will likely contribute to new robust updrafts developing along the MCS outflow/differential- heating zone. Will maintain MRGL risk across this region, although somewhat higher severe probabilities may be warranted, especially across KY along the southern flank of the forward-propagating MCS. Later in the day, very strong surface heating across the southern Plains will result in steep surface-3km lapse rates from northwest TX, across central into northeast OK. As the northern Plains trough shifts east, mid-level flow will begin to turn more westerly across northern OK, and 500mb speeds will increase to 25-40kt north of I-40. Convective temperatures will be breached by 22z, just ahead of the surface front, and scattered thunderstorms should easily develop along the wind shift. PWs will be very high across this region with values in excess of 2 inches. With temp/dew point spreads around 30F, there is increasing confidence that the most robust convection should generate severe downdrafts. A fairly concentrated corridor of convection should evolve downstream into the MO Ozarks by early evening. ..Darrow/Squitieri.. 07/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MISSISSIPPI VALLEY AND FROM THE MISSOURI OZARKS INTO THE SOUTHERN PLAINS... ...SUMMARY... Severe thunderstorms will be possible across parts of the Upper Mississippi Valley, Ozarks, and southern Plains. ...Discussion... Seasonally strong upper trough is shifting east across the northern Plains early this morning. This feature is forecast to advance toward the middle MO Valley by late afternoon as 500mb, 60kt speed max translates across southeast NE into IA. Left exit region of this speed max will spread across the upper MS Valley along with a corridor of modest 12hr mid-level height falls. Latest model guidance suggests a weak surface low will develop and track along the MN/IA border into southwest WI by late evening. This corridor appears favorable for robust convective development as boundary layer warms and convective temperatures are breached, likely by midday, as readings warm through the upper 70s-80F. Forecast soundings exhibit veering wind profiles with height, and some supercell potential exists within this zone of focused ascent. Large hail and locally damaging winds are the primary concerns. Farther south, an expansive corridor of convection has evolved over the central Plains early this morning. Upscale growth may continue for the next few hours, and a long-lived MCS should propagate across eastern KS into MO by sunrise. While this complex may not be particularly severe at daybreak, a long-lived MCS, or its remnants, will advance downstream into the OH Valley as modest mid-level flow will extend along a corridor from MO into southern OH. Models are not too aggressive in steepening low-level lapse rates east of the MS River later today, but some surface heating is expected to contribute to increased buoyancy that will likely contribute to new robust updrafts developing along the MCS outflow/differential- heating zone. Will maintain MRGL risk across this region, although somewhat higher severe probabilities may be warranted, especially across KY along the southern flank of the forward-propagating MCS. Later in the day, very strong surface heating across the southern Plains will result in steep surface-3km lapse rates from northwest TX, across central into northeast OK. As the northern Plains trough shifts east, mid-level flow will begin to turn more westerly across northern OK, and 500mb speeds will increase to 25-40kt north of I-40. Convective temperatures will be breached by 22z, just ahead of the surface front, and scattered thunderstorms should easily develop along the wind shift. PWs will be very high across this region with values in excess of 2 inches. With temp/dew point spreads around 30F, there is increasing confidence that the most robust convection should generate severe downdrafts. A fairly concentrated corridor of convection should evolve downstream into the MO Ozarks by early evening. ..Darrow/Squitieri.. 07/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 04 2024 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MISSISSIPPI VALLEY AND FROM THE MISSOURI OZARKS INTO THE SOUTHERN PLAINS... ...SUMMARY... Severe thunderstorms will be possible across parts of the Upper Mississippi Valley, Ozarks, and southern Plains. ...Discussion... Seasonally strong upper trough is shifting east across the northern Plains early this morning. This feature is forecast to advance toward the middle MO Valley by late afternoon as 500mb, 60kt speed max translates across southeast NE into IA. Left exit region of this speed max will spread across the upper MS Valley along with a corridor of modest 12hr mid-level height falls. Latest model guidance suggests a weak surface low will develop and track along the MN/IA border into southwest WI by late evening. This corridor appears favorable for robust convective development as boundary layer warms and convective temperatures are breached, likely by midday, as readings warm through the upper 70s-80F. Forecast soundings exhibit veering wind profiles with height, and some supercell potential exists within this zone of focused ascent. Large hail and locally damaging winds are the primary concerns. Farther south, an expansive corridor of convection has evolved over the central Plains early this morning. Upscale growth may continue for the next few hours, and a long-lived MCS should propagate across eastern KS into MO by sunrise. While this complex may not be particularly severe at daybreak, a long-lived MCS, or its remnants, will advance downstream into the OH Valley as modest mid-level flow will extend along a corridor from MO into southern OH. Models are not too aggressive in steepening low-level lapse rates east of the MS River later today, but some surface heating is expected to contribute to increased buoyancy that will likely contribute to new robust updrafts developing along the MCS outflow/differential- heating zone. Will maintain MRGL risk across this region, although somewhat higher severe probabilities may be warranted, especially across KY along the southern flank of the forward-propagating MCS. Later in the day, very strong surface heating across the southern Plains will result in steep surface-3km lapse rates from northwest TX, across central into northeast OK. As the northern Plains trough shifts east, mid-level flow will begin to turn more westerly across northern OK, and 500mb speeds will increase to 25-40kt north of I-40. Convective temperatures will be breached by 22z, just ahead of the surface front, and scattered thunderstorms should easily develop along the wind shift. PWs will be very high across this region with values in excess of 2 inches. With temp/dew point spreads around 30F, there is increasing confidence that the most robust convection should generate severe downdrafts. A fairly concentrated corridor of convection should evolve downstream into the MO Ozarks by early evening. ..Darrow/Squitieri.. 07/04/2024 Read more