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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Thu Apr 18 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHEAST TOWARD THE CAROLINA PIEDMONT... ...SUMMARY... Sporadic strong to marginally severe storms are still possible tomorrow (Friday) over parts of the Southeast. ...Synopsis... A broad mid-level trough will traverse Ontario and Quebec, with mainly zonal flow overspreading the central and northern CONUS tomorrow (Friday). Meanwhile, a smaller mid-level trough is poised to eject into the southern High Plains at the end of the period. A surface cold front will sweep across the eastern U.S. in advance of the first mid-level trough, providing enough low-level ascent to support scattered strong thunderstorm development given adequate buoyancy and vertical wind shear preceding the front. For Friday night into Saturday morning, the approach of the southwestern mid-level trough will encourage low-level jet development over the southern Plains, with scattered to widespread thunderstorm development expected along the low-level jet terminus, where low-level convergence will be strongest. ...Parts of the Southeast toward the Carolina Piedmont... Surface temperatures are expected to warm above 80 F amid low to mid 60s F dewpoints ahead of the surface cold front, boosting SBCAPE from 1000-2000 J/kg across the warm sector. Modest westerly 500 mb flow from the glancing mid-level trough will overspread a 15-20 kt southwesterly 850 mb wind field, resulting in elongated hodographs and 40+ kts of effective bulk shear. As such, organized multicells and transient supercells are expected to initiate ahead of the cold front by afternoon, accompanied by occasional instances of hail and gusty winds. A couple instances of severe hail/wind could occur with some of the stronger storms, especially if a more pronounced supercell structure can become established. ...Central and northern Texas... A strongly capped boundary layer is expected to reside across much of TX through the period, limiting the chances for surface-based convective initiation. As the low level jet strengthens overnight, the jet terminus is expected to become situated somewhere near the Red River, where isentropic ascent should lift elevated buoyant parcels to their LFC and initiate scattered to potentially numerous thunderstorms. LFCs are expected to be between 700-600 mb, which should restrict CAPE to thin profiles, limiting severe hail production. Nonetheless, given elongated hodographs and steep mid-level lapse rates, at least small hail is possible and a sparse instance of severe hail cannot be ruled out, though the coverage seems too isolated/localized to warrant probabilities at this time. ..Squitieri.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Apr 18 2024 Valid 181630Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY TONIGHT FOR PARTS OF THE MID MS AND LOWER OH VALLEYS... ...SUMMARY... Damaging gusts to 70 mph, large hail up to 2 inches in diameter, and a couple of tornadoes are expected mainly this afternoon into early tonight across the middle Mississippi and lower Ohio Valleys. More isolated large hail and damaging winds will be possible farther south from northern Mississippi and Arkansas into central Texas. ...Mid MS/lower OH Valleys through tonight... Recent surface analysis places a low just south of MCI along the KS/MO border vicinity. A warm front extends eastward from this low across central MO, far southern IL and into KY. Airmass south of this warm front is moderately moist, with observations sampling mid 60s dewpoints along much of the AR/MO border, with some upper 60s farther east over the MO Bootheel. Expectation is for this moist airmass to continue progressing northward throughout the day, likely reaching the I-70 corridor by the mid-afternoon. A cold front also extends southwestward from this low through north-central to southwest OK, continuing through northwest TX and southwest TX. An outflow boundary from overnight convection precedes this cold front, although by only about 30-50 miles or so. General expectation is for thunderstorm intensity and coverage to increase early this afternoon as these surface boundaries interact with the increasingly moist and unstable boundary layer downstream. Overall convective evolution is a bit more uncertain, particularly regarding when the storms become more balanced with the cold front and/or outflow no longer undercutting updrafts. Current thinking is that this occurs during the early afternoon across central MO, with quick upscale growth promoting an organized convective line. Primary risk within this line will be damaging wind gusts from 45 to 65 mph. Large hail from 1 to 2" is also possible, particularly with any more cellular development ahead of the front and/or outflow. A similar convective evolution appears likely farther north (from central MO into central/southern IL and western IN) near the surface low, but with augmented mesoscale ascent near the low. This augmented ascent could contribute to more vigorous updrafts and a somewhat more organized convective structure, despite being displaced north of the better low-level moisture and buoyancy. Additionally, the eastward-progressing low will allow storms here to be more favorably aligned with the deep-layer vertical shear. This could contribute to a more forward-propagating structure and the potential for damaging gusts, despite modest thermodynamics. As a result, the outlook probabilities were shifted a bit northeastward across IL and IN. Primary threat here is wind gusts, although the backed low-level flow near the surface low could contribute some tornado threat as well. ...Much of AR through southeast OK and into North/Central TX this afternoon/evening... A cold front extends southwestward from a low near the KS/MO border southwestward through north-central to southwest OK, continuing through northwest TX and southwest TX. Surface heating ahead of this front is expected to result in strong buoyancy within the moist airmass that is already in place across the region. Widely scattered to scattered thunderstorm development is expected by about 21z along the front from northwest AR across southeast OK into north and central TX. Deep-layer shear will be strong enough for some supercell structures capable of producing isolated very large hail (up to 2.5 inches in diameter), along with damaging outflow gusts given the potential for strong downdrafts. These storms will last a few hours into late evening and then weaken as convective inhibition increases. ...Southeast AR into Northern MS this afternoon/evening... As mentioned in MCD #480, slightly elevated convection continues to evolve across the Arkansas/Louisiana border area this morning, within a zone of QG ascent ahead of a subtle shortwave trough moving across east Texas. This shortwave is expected to continue progressing northeastward, with the ongoing storms likely persisting as they move northeastward as well. General expectation is for this cluster to maintain its intensity for the next few hours, with some hail possible, before likely waning thereafter as the low-level jet weakens and veers. However, that is a fairly low confidence scenario given that this cluster developed about 4 hours ahead of when much of the guidance indicated. Additional development appears probable in the wake of this cluster over northern LA/southern AR this afternoon. In this area, weak ascent preceding the shortwave will interact with the unstable warm sector for widely scattered thunderstorm development this afternoon. If a few storms do form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, with the threat expanding eastward into northern/central MS over time. ..Mosier/Bentley.. 04/18/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...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 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...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 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...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 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...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 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...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 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...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 1121 AM CDT Thu Apr 18 2024 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 04/18/2024 .PREV DISCUSSION... /ISSUED 0148 AM CDT Thu Apr 18 2024/ ...Synopsis... Zonal mid-level flow is expected over much of the US as a broad low-amplitude trough moves over the central CONUS. Weak ridging is expected farther south which will force stronger flow aloft to remain displaced over the northern third of the country. At the surface, a low will move eastward with the broad trough while a cold front moves south over much of the Plains. Much cooler temperatures, higher humidity, and weaker winds are expected within the post-frontal air mass. The only exception to this may be across far northeast NM and southern CO where the air mass is expected to remain drier and could support a few hours of locally elevated fire-weather concerns. Otherwise, fire-weather concerns appear unlikely over much of the CONUS today. ...Please see www.spc.noaa.gov/fire for graphic product... Read more