Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Sat May 04 2024 Valid 041300Z - 051200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF WEST TEXAS AND EXTREME SOUTHEASTERN NEW MEXICO... ...SUMMARY... Scattered severe thunderstorms are expected across parts of the southern High Plains into the Hill Country of central Texas this afternoon and evening. Several storms may produce very large hail, and a couple strong tornadoes are possible. ...Synopsis... Starting today and for several more, the greatest mid upper-level influence on severe-thunderstorm potential will be related to a well-developed cyclone now centered over the northeastern Pacific, about 250 nm west of ONP. The associated 500-mb low should dig southeastward to northeastern CA by the end of the period (12Z tomorrow), with a large swath of preceding difluent flow spreading over the Rocky Mountain States. In response to these developments, a southern-stream perturbation -- evident in moisture-channel imagery from parts of AZ across northern/central Baja -- will pivot east-northeastward. This feature should reach southern NM and Chihuahua by 00Z, then merge with convectively generated vorticity over west TX this evening. The perturbation then should reach western OK and north-central to south-central TX by 12Z. At the surface, 11Z analysis showed an elongated area of low pressure over southwestern to north-central IA, with cold front southwestward across southeastern KS, southwestern OK, and the Llano Estacado between PVW-CVS. A warm front was analyzed from southeastern IA across northeastern MO and southern IL. As the low-pressure area migrates toward Lake Michigan by 00Z, the cold front is forecast to reach northeastern to extreme southern IL, the central Ozarks, southern OK, and west-central TX, becoming muddled by convective processes southwestward through the Permian Basin/ lower Pecos Valley region. By 12Z, the low should reach eastern Lower MI, with cold front over IN, central AR, and northeast TX, becoming ill-defined amid expansive outflow southwestward from there in TX. The warm front should reach eastern IL, central IN and northwestern OH by 00Z. ...TX/southern OK/extreme southeastern NM... Widely scattered to scattered thunderstorms are expected to form this afternoon along and behind the cold front over west TX and southeastern NM, as well as ahead of the cold front, near the dryline and over strongly heated, relatively high elevations west of the Pecos Valley. Large hail will be a threat on both sides of the front, with severe-wind and tornado potential more prevalent to its south. One or two dominant, prefrontal, mid/late-afternoon supercells may evolve and remain south of the front -- through the lower Pecos Valley/FST region -- to sustain threats for strong tornadoes and very large/destructive hail. As in the last few days, storm-boundary and storm-storm interactions may factor importantly into localized enhancement of tornado risk. Strong heating and moist advection are expected this afternoon south of the front, increasing theta-e and reducing MLCINH in support of initiation. 70s F surface dewpoints are already present not far upstream in the Rio Grande Valley and below the Balcones Escarpment, around DRT-UVA. Mid 60s to near 70 F dewpoints and 1-1.5-inch PW should be common east of the dryline, and between the front and the Rio Grande, by late afternoon, supporting MLCAPE of 2500-3500 J/kg amid steep low/middle-level lapse rates. Kinematically, by 00Z, this area will be in a vertical superposition of: 1. The supportive large-scale ascent regime of the left-exit region of a broad subtropical jet, whose axis remains over northern MX. 2. A strengthening, southeasterly LLJ, lengthening/enlarging the hodograph. This LLJ also should transport rich low-level moisture into convection over the region, while providing strong storm-relative low-level winds. 3. Strengthening flow near 500 mb, supporting increases in effective-shear magnitudes to around 45-60 kt. Upscale merger/growth of convection is expected this evening, with resulting MCS shifting eastward over the Edwards Plateau/Hill Country before weakening late tonight. Damaging to severe gusts will become the main threat, though embedded tornadic circulations and isolated large hail will remain possible. The northern part of this activity also may grow/merge with initially separate, less- organized (but still potentially marginally severe) convection in the Red River region of southern OK and north TX. ...North/northeast TX to mid Mississippi Valley vicinity... Isolated to scattered thunderstorms -- some in lines and multicellular clusters -- should affect portions of this broad corridor today into this evening along and ahead of the surface cold front. Isolated damaging to severe gusts and large hail are the main concerns. Due to limited low/middle-level lapse rates, adequate but not rich moisture, and modest vertical shear, severe potential in this swath should be less focused, and more marginal in magnitude than over the "slight" and "enhanced" areas. ..Edwards/Broyles.. 05/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Sat May 04 2024 Valid 041300Z - 051200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF WEST TEXAS AND EXTREME SOUTHEASTERN NEW MEXICO... ...SUMMARY... Scattered severe thunderstorms are expected across parts of the southern High Plains into the Hill Country of central Texas this afternoon and evening. Several storms may produce very large hail, and a couple strong tornadoes are possible. ...Synopsis... Starting today and for several more, the greatest mid upper-level influence on severe-thunderstorm potential will be related to a well-developed cyclone now centered over the northeastern Pacific, about 250 nm west of ONP. The associated 500-mb low should dig southeastward to northeastern CA by the end of the period (12Z tomorrow), with a large swath of preceding difluent flow spreading over the Rocky Mountain States. In response to these developments, a southern-stream perturbation -- evident in moisture-channel imagery from parts of AZ across northern/central Baja -- will pivot east-northeastward. This feature should reach southern NM and Chihuahua by 00Z, then merge with convectively generated vorticity over west TX this evening. The perturbation then should reach western OK and north-central to south-central TX by 12Z. At the surface, 11Z analysis showed an elongated area of low pressure over southwestern to north-central IA, with cold front southwestward across southeastern KS, southwestern OK, and the Llano Estacado between PVW-CVS. A warm front was analyzed from southeastern IA across northeastern MO and southern IL. As the low-pressure area migrates toward Lake Michigan by 00Z, the cold front is forecast to reach northeastern to extreme southern IL, the central Ozarks, southern OK, and west-central TX, becoming muddled by convective processes southwestward through the Permian Basin/ lower Pecos Valley region. By 12Z, the low should reach eastern Lower MI, with cold front over IN, central AR, and northeast TX, becoming ill-defined amid expansive outflow southwestward from there in TX. The warm front should reach eastern IL, central IN and northwestern OH by 00Z. ...TX/southern OK/extreme southeastern NM... Widely scattered to scattered thunderstorms are expected to form this afternoon along and behind the cold front over west TX and southeastern NM, as well as ahead of the cold front, near the dryline and over strongly heated, relatively high elevations west of the Pecos Valley. Large hail will be a threat on both sides of the front, with severe-wind and tornado potential more prevalent to its south. One or two dominant, prefrontal, mid/late-afternoon supercells may evolve and remain south of the front -- through the lower Pecos Valley/FST region -- to sustain threats for strong tornadoes and very large/destructive hail. As in the last few days, storm-boundary and storm-storm interactions may factor importantly into localized enhancement of tornado risk. Strong heating and moist advection are expected this afternoon south of the front, increasing theta-e and reducing MLCINH in support of initiation. 70s F surface dewpoints are already present not far upstream in the Rio Grande Valley and below the Balcones Escarpment, around DRT-UVA. Mid 60s to near 70 F dewpoints and 1-1.5-inch PW should be common east of the dryline, and between the front and the Rio Grande, by late afternoon, supporting MLCAPE of 2500-3500 J/kg amid steep low/middle-level lapse rates. Kinematically, by 00Z, this area will be in a vertical superposition of: 1. The supportive large-scale ascent regime of the left-exit region of a broad subtropical jet, whose axis remains over northern MX. 2. A strengthening, southeasterly LLJ, lengthening/enlarging the hodograph. This LLJ also should transport rich low-level moisture into convection over the region, while providing strong storm-relative low-level winds. 3. Strengthening flow near 500 mb, supporting increases in effective-shear magnitudes to around 45-60 kt. Upscale merger/growth of convection is expected this evening, with resulting MCS shifting eastward over the Edwards Plateau/Hill Country before weakening late tonight. Damaging to severe gusts will become the main threat, though embedded tornadic circulations and isolated large hail will remain possible. The northern part of this activity also may grow/merge with initially separate, less- organized (but still potentially marginally severe) convection in the Red River region of southern OK and north TX. ...North/northeast TX to mid Mississippi Valley vicinity... Isolated to scattered thunderstorms -- some in lines and multicellular clusters -- should affect portions of this broad corridor today into this evening along and ahead of the surface cold front. Isolated damaging to severe gusts and large hail are the main concerns. Due to limited low/middle-level lapse rates, adequate but not rich moisture, and modest vertical shear, severe potential in this swath should be less focused, and more marginal in magnitude than over the "slight" and "enhanced" areas. ..Edwards/Broyles.. 05/04/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat May 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... An active period of organized severe thunderstorms should persist into at least the middle of next week across parts of the southern Plains into the mid MS Valley, Mid-South, and Midwest/OH Valley. The 15% severe areas for both Day 4/Tuesday and Day 5/Wednesday have been expanded based on latest model trends. ...Day 4/Tuesday... The primary upper low over the northern Plains is forecast to gradually occlude on Tuesday. But, a strong mid-level jet streak should overspread parts of the mid MS Valley and Midwest through the day. A secondary surface low should develop northeastward across these regions, with a warm front also lifting northward towards southern WI and southern Lower MI. Thunderstorms related to low-level warm advection and activity that has spread eastward from the southern/central Plains may be ongoing Tuesday morning. It remains unclear if these thunderstorms will strengthen once again as they develop eastward in tandem with a destabilizing warm sector. Additional robust convection will likely develop Tuesday afternoon farther south along the dryline over the Ozarks and Mid-South. A favorable parameter space for supercells and all severe hazards remains evident, with the threat for severe thunderstorms continuing Tuesday afternoon/evening across parts of the OH Valley. ...Day 5/Wednesday... Although some differences in model guidance regarding the upper-air pattern across the central/eastern CONUS begin to emerge by Wednesday, there is still good agreement that a belt of strong mid-level flow will remain in place from the southern/central Plains northeastward to the OH Valley and Great Lakes. It appears that another embedded shortwave trough will advance eastward from the southern/central Plains into the mid MS Valley by Wednesday evening. A very moist and moderately to strongly unstable airmass should reside to the east of a cold front/dryline across these regions, potentially extending as far north into much of the Midwest/OH Valley. Strong deep-layer shear will favor organized convection, including supercells and bowing line segments posing a threat for all severe hazards. Depending on the influence of prior convection, the very favorable parameter space forecast for Wednesday across parts of the southern Plains into the mid MS Valley and OH Valley may necessitate greater severe probabilities in a later outlook. ...Day 6/Thursday... Multiple days of robust and potentially widespread convection complicates the severe potential for Thursday. Still, some severe risk remains evident along/south of what will probably be a convectively reinforced front/boundary extending across parts of the southern Plains into the Southeast and Mid-Atlantic. It is possible that one or more 15% severe areas for Thursday will be needed for these regions given favorable forecast instability/shear. But, this is still dependent on better agreement in model guidance regarding the extent/placement of moderate to strong instability, and overall convective coverage Thursday afternoon/evening. ...Day 7/Friday and Day 8/Saturday... The spatial extent of the warm sector should tend to become more confined late next week and into the weekend. There is a fair amount of spread in model guidance regarding the strength and placement of an upper trough/low over the eastern CONUS in this time frame. Still, a severe risk may continue Friday along/south of a front that should be in place over parts of the Southeast. Any lingering severe threat into Saturday may be even farther south and confined to mainly parts of FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat May 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... An active period of organized severe thunderstorms should persist into at least the middle of next week across parts of the southern Plains into the mid MS Valley, Mid-South, and Midwest/OH Valley. The 15% severe areas for both Day 4/Tuesday and Day 5/Wednesday have been expanded based on latest model trends. ...Day 4/Tuesday... The primary upper low over the northern Plains is forecast to gradually occlude on Tuesday. But, a strong mid-level jet streak should overspread parts of the mid MS Valley and Midwest through the day. A secondary surface low should develop northeastward across these regions, with a warm front also lifting northward towards southern WI and southern Lower MI. Thunderstorms related to low-level warm advection and activity that has spread eastward from the southern/central Plains may be ongoing Tuesday morning. It remains unclear if these thunderstorms will strengthen once again as they develop eastward in tandem with a destabilizing warm sector. Additional robust convection will likely develop Tuesday afternoon farther south along the dryline over the Ozarks and Mid-South. A favorable parameter space for supercells and all severe hazards remains evident, with the threat for severe thunderstorms continuing Tuesday afternoon/evening across parts of the OH Valley. ...Day 5/Wednesday... Although some differences in model guidance regarding the upper-air pattern across the central/eastern CONUS begin to emerge by Wednesday, there is still good agreement that a belt of strong mid-level flow will remain in place from the southern/central Plains northeastward to the OH Valley and Great Lakes. It appears that another embedded shortwave trough will advance eastward from the southern/central Plains into the mid MS Valley by Wednesday evening. A very moist and moderately to strongly unstable airmass should reside to the east of a cold front/dryline across these regions, potentially extending as far north into much of the Midwest/OH Valley. Strong deep-layer shear will favor organized convection, including supercells and bowing line segments posing a threat for all severe hazards. Depending on the influence of prior convection, the very favorable parameter space forecast for Wednesday across parts of the southern Plains into the mid MS Valley and OH Valley may necessitate greater severe probabilities in a later outlook. ...Day 6/Thursday... Multiple days of robust and potentially widespread convection complicates the severe potential for Thursday. Still, some severe risk remains evident along/south of what will probably be a convectively reinforced front/boundary extending across parts of the southern Plains into the Southeast and Mid-Atlantic. It is possible that one or more 15% severe areas for Thursday will be needed for these regions given favorable forecast instability/shear. But, this is still dependent on better agreement in model guidance regarding the extent/placement of moderate to strong instability, and overall convective coverage Thursday afternoon/evening. ...Day 7/Friday and Day 8/Saturday... The spatial extent of the warm sector should tend to become more confined late next week and into the weekend. There is a fair amount of spread in model guidance regarding the strength and placement of an upper trough/low over the eastern CONUS in this time frame. Still, a severe risk may continue Friday along/south of a front that should be in place over parts of the Southeast. Any lingering severe threat into Saturday may be even farther south and confined to mainly parts of FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat May 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... An active period of organized severe thunderstorms should persist into at least the middle of next week across parts of the southern Plains into the mid MS Valley, Mid-South, and Midwest/OH Valley. The 15% severe areas for both Day 4/Tuesday and Day 5/Wednesday have been expanded based on latest model trends. ...Day 4/Tuesday... The primary upper low over the northern Plains is forecast to gradually occlude on Tuesday. But, a strong mid-level jet streak should overspread parts of the mid MS Valley and Midwest through the day. A secondary surface low should develop northeastward across these regions, with a warm front also lifting northward towards southern WI and southern Lower MI. Thunderstorms related to low-level warm advection and activity that has spread eastward from the southern/central Plains may be ongoing Tuesday morning. It remains unclear if these thunderstorms will strengthen once again as they develop eastward in tandem with a destabilizing warm sector. Additional robust convection will likely develop Tuesday afternoon farther south along the dryline over the Ozarks and Mid-South. A favorable parameter space for supercells and all severe hazards remains evident, with the threat for severe thunderstorms continuing Tuesday afternoon/evening across parts of the OH Valley. ...Day 5/Wednesday... Although some differences in model guidance regarding the upper-air pattern across the central/eastern CONUS begin to emerge by Wednesday, there is still good agreement that a belt of strong mid-level flow will remain in place from the southern/central Plains northeastward to the OH Valley and Great Lakes. It appears that another embedded shortwave trough will advance eastward from the southern/central Plains into the mid MS Valley by Wednesday evening. A very moist and moderately to strongly unstable airmass should reside to the east of a cold front/dryline across these regions, potentially extending as far north into much of the Midwest/OH Valley. Strong deep-layer shear will favor organized convection, including supercells and bowing line segments posing a threat for all severe hazards. Depending on the influence of prior convection, the very favorable parameter space forecast for Wednesday across parts of the southern Plains into the mid MS Valley and OH Valley may necessitate greater severe probabilities in a later outlook. ...Day 6/Thursday... Multiple days of robust and potentially widespread convection complicates the severe potential for Thursday. Still, some severe risk remains evident along/south of what will probably be a convectively reinforced front/boundary extending across parts of the southern Plains into the Southeast and Mid-Atlantic. It is possible that one or more 15% severe areas for Thursday will be needed for these regions given favorable forecast instability/shear. But, this is still dependent on better agreement in model guidance regarding the extent/placement of moderate to strong instability, and overall convective coverage Thursday afternoon/evening. ...Day 7/Friday and Day 8/Saturday... The spatial extent of the warm sector should tend to become more confined late next week and into the weekend. There is a fair amount of spread in model guidance regarding the strength and placement of an upper trough/low over the eastern CONUS in this time frame. Still, a severe risk may continue Friday along/south of a front that should be in place over parts of the Southeast. Any lingering severe threat into Saturday may be even farther south and confined to mainly parts of FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat May 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... An active period of organized severe thunderstorms should persist into at least the middle of next week across parts of the southern Plains into the mid MS Valley, Mid-South, and Midwest/OH Valley. The 15% severe areas for both Day 4/Tuesday and Day 5/Wednesday have been expanded based on latest model trends. ...Day 4/Tuesday... The primary upper low over the northern Plains is forecast to gradually occlude on Tuesday. But, a strong mid-level jet streak should overspread parts of the mid MS Valley and Midwest through the day. A secondary surface low should develop northeastward across these regions, with a warm front also lifting northward towards southern WI and southern Lower MI. Thunderstorms related to low-level warm advection and activity that has spread eastward from the southern/central Plains may be ongoing Tuesday morning. It remains unclear if these thunderstorms will strengthen once again as they develop eastward in tandem with a destabilizing warm sector. Additional robust convection will likely develop Tuesday afternoon farther south along the dryline over the Ozarks and Mid-South. A favorable parameter space for supercells and all severe hazards remains evident, with the threat for severe thunderstorms continuing Tuesday afternoon/evening across parts of the OH Valley. ...Day 5/Wednesday... Although some differences in model guidance regarding the upper-air pattern across the central/eastern CONUS begin to emerge by Wednesday, there is still good agreement that a belt of strong mid-level flow will remain in place from the southern/central Plains northeastward to the OH Valley and Great Lakes. It appears that another embedded shortwave trough will advance eastward from the southern/central Plains into the mid MS Valley by Wednesday evening. A very moist and moderately to strongly unstable airmass should reside to the east of a cold front/dryline across these regions, potentially extending as far north into much of the Midwest/OH Valley. Strong deep-layer shear will favor organized convection, including supercells and bowing line segments posing a threat for all severe hazards. Depending on the influence of prior convection, the very favorable parameter space forecast for Wednesday across parts of the southern Plains into the mid MS Valley and OH Valley may necessitate greater severe probabilities in a later outlook. ...Day 6/Thursday... Multiple days of robust and potentially widespread convection complicates the severe potential for Thursday. Still, some severe risk remains evident along/south of what will probably be a convectively reinforced front/boundary extending across parts of the southern Plains into the Southeast and Mid-Atlantic. It is possible that one or more 15% severe areas for Thursday will be needed for these regions given favorable forecast instability/shear. But, this is still dependent on better agreement in model guidance regarding the extent/placement of moderate to strong instability, and overall convective coverage Thursday afternoon/evening. ...Day 7/Friday and Day 8/Saturday... The spatial extent of the warm sector should tend to become more confined late next week and into the weekend. There is a fair amount of spread in model guidance regarding the strength and placement of an upper trough/low over the eastern CONUS in this time frame. Still, a severe risk may continue Friday along/south of a front that should be in place over parts of the Southeast. Any lingering severe threat into Saturday may be even farther south and confined to mainly parts of FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat May 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... An active period of organized severe thunderstorms should persist into at least the middle of next week across parts of the southern Plains into the mid MS Valley, Mid-South, and Midwest/OH Valley. The 15% severe areas for both Day 4/Tuesday and Day 5/Wednesday have been expanded based on latest model trends. ...Day 4/Tuesday... The primary upper low over the northern Plains is forecast to gradually occlude on Tuesday. But, a strong mid-level jet streak should overspread parts of the mid MS Valley and Midwest through the day. A secondary surface low should develop northeastward across these regions, with a warm front also lifting northward towards southern WI and southern Lower MI. Thunderstorms related to low-level warm advection and activity that has spread eastward from the southern/central Plains may be ongoing Tuesday morning. It remains unclear if these thunderstorms will strengthen once again as they develop eastward in tandem with a destabilizing warm sector. Additional robust convection will likely develop Tuesday afternoon farther south along the dryline over the Ozarks and Mid-South. A favorable parameter space for supercells and all severe hazards remains evident, with the threat for severe thunderstorms continuing Tuesday afternoon/evening across parts of the OH Valley. ...Day 5/Wednesday... Although some differences in model guidance regarding the upper-air pattern across the central/eastern CONUS begin to emerge by Wednesday, there is still good agreement that a belt of strong mid-level flow will remain in place from the southern/central Plains northeastward to the OH Valley and Great Lakes. It appears that another embedded shortwave trough will advance eastward from the southern/central Plains into the mid MS Valley by Wednesday evening. A very moist and moderately to strongly unstable airmass should reside to the east of a cold front/dryline across these regions, potentially extending as far north into much of the Midwest/OH Valley. Strong deep-layer shear will favor organized convection, including supercells and bowing line segments posing a threat for all severe hazards. Depending on the influence of prior convection, the very favorable parameter space forecast for Wednesday across parts of the southern Plains into the mid MS Valley and OH Valley may necessitate greater severe probabilities in a later outlook. ...Day 6/Thursday... Multiple days of robust and potentially widespread convection complicates the severe potential for Thursday. Still, some severe risk remains evident along/south of what will probably be a convectively reinforced front/boundary extending across parts of the southern Plains into the Southeast and Mid-Atlantic. It is possible that one or more 15% severe areas for Thursday will be needed for these regions given favorable forecast instability/shear. But, this is still dependent on better agreement in model guidance regarding the extent/placement of moderate to strong instability, and overall convective coverage Thursday afternoon/evening. ...Day 7/Friday and Day 8/Saturday... The spatial extent of the warm sector should tend to become more confined late next week and into the weekend. There is a fair amount of spread in model guidance regarding the strength and placement of an upper trough/low over the eastern CONUS in this time frame. Still, a severe risk may continue Friday along/south of a front that should be in place over parts of the Southeast. Any lingering severe threat into Saturday may be even farther south and confined to mainly parts of FL. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Sat May 04 2024 Valid 061200Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms will likely develop and move eastward Monday afternoon and evening across parts of the southern/central Plains. Strong tornadoes, very large to giant hail, and damaging winds all appear possible. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low should consolidate over the northern High Plains of eastern MT/western ND and vicinity, with a secondary surface low possibly developing over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline. A warm front should eventually extend eastward across parts of NE/IA, and this boundary will probably be the northern limit of appreciable severe-thunderstorm potential. ...Southern/Central Plains... A severe-weather outbreak still appears possible across parts of the southern/central Plains on Monday, focused from south-central/ southeast NE into central/eastern KS and much of OK. Robust diurnal heating of the moist low-level airmass, coupled with steep mid-level lapse rates overspreading much of the warm sector, will likely foster moderate to strong instability (MLCAPE generally ranging from 2000-3500 J/kg) by Monday afternoon. Enhanced mid-level winds and a favorably veering/strengthening wind profile with height through mid/upper levels will support around 40-55 kt of effective bulk shear, stronger with northward extent in KS/NE. Current expectations are for scattered supercells to erupt along the length of the dryline in south-central NE and western/central KS by mid to late Monday afternoon, coincident with stronger large-scale ascent overspreading this region. Given the rather favorable thermodynamic and kinematic parameter space, very large to giant hail (2-4 inch diameter) will likely be a threat with these initial supercells. The threat for tornadoes should quickly increase through the late afternoon and early evening in tandem with a strengthening southerly low-level jet. Ample 0-1 km and effective SRH shown in various NAM/GFS forecast soundings suggest a threat for strong tornadoes with any supercell that can remain discrete. With time Monday evening and into early Tuesday morning, upscale growth into multiple linear structures is probable, with an increased threat for severe/damaging winds, along with embedded tornadoes given the forecast strength of the low-level shear. The southward extent of the substantial severe risk into OK and north TX remains somewhat uncertain, as better forcing for ascent will tend to remain across the central Plains. Still, modest mid-level height falls should encourage isolated to perhaps widely scatted supercells developing along the length of the dryline into the southern Plains. Very large hail and strong tornadoes will be the main threats with any supercell that can develop and persist across this region Monday afternoon/evening. Model trends will also be monitored for a more favorable corridor of strong tornadoes and giant hail, which may necessitate greater severe probabilities for Monday in a later outlook. ..Gleason.. 05/04/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Sat May 04 2024 Valid 061200Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms will likely develop and move eastward Monday afternoon and evening across parts of the southern/central Plains. Strong tornadoes, very large to giant hail, and damaging winds all appear possible. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low should consolidate over the northern High Plains of eastern MT/western ND and vicinity, with a secondary surface low possibly developing over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline. A warm front should eventually extend eastward across parts of NE/IA, and this boundary will probably be the northern limit of appreciable severe-thunderstorm potential. ...Southern/Central Plains... A severe-weather outbreak still appears possible across parts of the southern/central Plains on Monday, focused from south-central/ southeast NE into central/eastern KS and much of OK. Robust diurnal heating of the moist low-level airmass, coupled with steep mid-level lapse rates overspreading much of the warm sector, will likely foster moderate to strong instability (MLCAPE generally ranging from 2000-3500 J/kg) by Monday afternoon. Enhanced mid-level winds and a favorably veering/strengthening wind profile with height through mid/upper levels will support around 40-55 kt of effective bulk shear, stronger with northward extent in KS/NE. Current expectations are for scattered supercells to erupt along the length of the dryline in south-central NE and western/central KS by mid to late Monday afternoon, coincident with stronger large-scale ascent overspreading this region. Given the rather favorable thermodynamic and kinematic parameter space, very large to giant hail (2-4 inch diameter) will likely be a threat with these initial supercells. The threat for tornadoes should quickly increase through the late afternoon and early evening in tandem with a strengthening southerly low-level jet. Ample 0-1 km and effective SRH shown in various NAM/GFS forecast soundings suggest a threat for strong tornadoes with any supercell that can remain discrete. With time Monday evening and into early Tuesday morning, upscale growth into multiple linear structures is probable, with an increased threat for severe/damaging winds, along with embedded tornadoes given the forecast strength of the low-level shear. The southward extent of the substantial severe risk into OK and north TX remains somewhat uncertain, as better forcing for ascent will tend to remain across the central Plains. Still, modest mid-level height falls should encourage isolated to perhaps widely scatted supercells developing along the length of the dryline into the southern Plains. Very large hail and strong tornadoes will be the main threats with any supercell that can develop and persist across this region Monday afternoon/evening. Model trends will also be monitored for a more favorable corridor of strong tornadoes and giant hail, which may necessitate greater severe probabilities for Monday in a later outlook. ..Gleason.. 05/04/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Sat May 04 2024 Valid 061200Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms will likely develop and move eastward Monday afternoon and evening across parts of the southern/central Plains. Strong tornadoes, very large to giant hail, and damaging winds all appear possible. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low should consolidate over the northern High Plains of eastern MT/western ND and vicinity, with a secondary surface low possibly developing over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline. A warm front should eventually extend eastward across parts of NE/IA, and this boundary will probably be the northern limit of appreciable severe-thunderstorm potential. ...Southern/Central Plains... A severe-weather outbreak still appears possible across parts of the southern/central Plains on Monday, focused from south-central/ southeast NE into central/eastern KS and much of OK. Robust diurnal heating of the moist low-level airmass, coupled with steep mid-level lapse rates overspreading much of the warm sector, will likely foster moderate to strong instability (MLCAPE generally ranging from 2000-3500 J/kg) by Monday afternoon. Enhanced mid-level winds and a favorably veering/strengthening wind profile with height through mid/upper levels will support around 40-55 kt of effective bulk shear, stronger with northward extent in KS/NE. Current expectations are for scattered supercells to erupt along the length of the dryline in south-central NE and western/central KS by mid to late Monday afternoon, coincident with stronger large-scale ascent overspreading this region. Given the rather favorable thermodynamic and kinematic parameter space, very large to giant hail (2-4 inch diameter) will likely be a threat with these initial supercells. The threat for tornadoes should quickly increase through the late afternoon and early evening in tandem with a strengthening southerly low-level jet. Ample 0-1 km and effective SRH shown in various NAM/GFS forecast soundings suggest a threat for strong tornadoes with any supercell that can remain discrete. With time Monday evening and into early Tuesday morning, upscale growth into multiple linear structures is probable, with an increased threat for severe/damaging winds, along with embedded tornadoes given the forecast strength of the low-level shear. The southward extent of the substantial severe risk into OK and north TX remains somewhat uncertain, as better forcing for ascent will tend to remain across the central Plains. Still, modest mid-level height falls should encourage isolated to perhaps widely scatted supercells developing along the length of the dryline into the southern Plains. Very large hail and strong tornadoes will be the main threats with any supercell that can develop and persist across this region Monday afternoon/evening. Model trends will also be monitored for a more favorable corridor of strong tornadoes and giant hail, which may necessitate greater severe probabilities for Monday in a later outlook. ..Gleason.. 05/04/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Sat May 04 2024 Valid 061200Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms will likely develop and move eastward Monday afternoon and evening across parts of the southern/central Plains. Strong tornadoes, very large to giant hail, and damaging winds all appear possible. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low should consolidate over the northern High Plains of eastern MT/western ND and vicinity, with a secondary surface low possibly developing over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline. A warm front should eventually extend eastward across parts of NE/IA, and this boundary will probably be the northern limit of appreciable severe-thunderstorm potential. ...Southern/Central Plains... A severe-weather outbreak still appears possible across parts of the southern/central Plains on Monday, focused from south-central/ southeast NE into central/eastern KS and much of OK. Robust diurnal heating of the moist low-level airmass, coupled with steep mid-level lapse rates overspreading much of the warm sector, will likely foster moderate to strong instability (MLCAPE generally ranging from 2000-3500 J/kg) by Monday afternoon. Enhanced mid-level winds and a favorably veering/strengthening wind profile with height through mid/upper levels will support around 40-55 kt of effective bulk shear, stronger with northward extent in KS/NE. Current expectations are for scattered supercells to erupt along the length of the dryline in south-central NE and western/central KS by mid to late Monday afternoon, coincident with stronger large-scale ascent overspreading this region. Given the rather favorable thermodynamic and kinematic parameter space, very large to giant hail (2-4 inch diameter) will likely be a threat with these initial supercells. The threat for tornadoes should quickly increase through the late afternoon and early evening in tandem with a strengthening southerly low-level jet. Ample 0-1 km and effective SRH shown in various NAM/GFS forecast soundings suggest a threat for strong tornadoes with any supercell that can remain discrete. With time Monday evening and into early Tuesday morning, upscale growth into multiple linear structures is probable, with an increased threat for severe/damaging winds, along with embedded tornadoes given the forecast strength of the low-level shear. The southward extent of the substantial severe risk into OK and north TX remains somewhat uncertain, as better forcing for ascent will tend to remain across the central Plains. Still, modest mid-level height falls should encourage isolated to perhaps widely scatted supercells developing along the length of the dryline into the southern Plains. Very large hail and strong tornadoes will be the main threats with any supercell that can develop and persist across this region Monday afternoon/evening. Model trends will also be monitored for a more favorable corridor of strong tornadoes and giant hail, which may necessitate greater severe probabilities for Monday in a later outlook. ..Gleason.. 05/04/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Sat May 04 2024 Valid 061200Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms will likely develop and move eastward Monday afternoon and evening across parts of the southern/central Plains. Strong tornadoes, very large to giant hail, and damaging winds all appear possible. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low should consolidate over the northern High Plains of eastern MT/western ND and vicinity, with a secondary surface low possibly developing over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline. A warm front should eventually extend eastward across parts of NE/IA, and this boundary will probably be the northern limit of appreciable severe-thunderstorm potential. ...Southern/Central Plains... A severe-weather outbreak still appears possible across parts of the southern/central Plains on Monday, focused from south-central/ southeast NE into central/eastern KS and much of OK. Robust diurnal heating of the moist low-level airmass, coupled with steep mid-level lapse rates overspreading much of the warm sector, will likely foster moderate to strong instability (MLCAPE generally ranging from 2000-3500 J/kg) by Monday afternoon. Enhanced mid-level winds and a favorably veering/strengthening wind profile with height through mid/upper levels will support around 40-55 kt of effective bulk shear, stronger with northward extent in KS/NE. Current expectations are for scattered supercells to erupt along the length of the dryline in south-central NE and western/central KS by mid to late Monday afternoon, coincident with stronger large-scale ascent overspreading this region. Given the rather favorable thermodynamic and kinematic parameter space, very large to giant hail (2-4 inch diameter) will likely be a threat with these initial supercells. The threat for tornadoes should quickly increase through the late afternoon and early evening in tandem with a strengthening southerly low-level jet. Ample 0-1 km and effective SRH shown in various NAM/GFS forecast soundings suggest a threat for strong tornadoes with any supercell that can remain discrete. With time Monday evening and into early Tuesday morning, upscale growth into multiple linear structures is probable, with an increased threat for severe/damaging winds, along with embedded tornadoes given the forecast strength of the low-level shear. The southward extent of the substantial severe risk into OK and north TX remains somewhat uncertain, as better forcing for ascent will tend to remain across the central Plains. Still, modest mid-level height falls should encourage isolated to perhaps widely scatted supercells developing along the length of the dryline into the southern Plains. Very large hail and strong tornadoes will be the main threats with any supercell that can develop and persist across this region Monday afternoon/evening. Model trends will also be monitored for a more favorable corridor of strong tornadoes and giant hail, which may necessitate greater severe probabilities for Monday in a later outlook. ..Gleason.. 05/04/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Sat May 04 2024 Valid 061200Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms will likely develop and move eastward Monday afternoon and evening across parts of the southern/central Plains. Strong tornadoes, very large to giant hail, and damaging winds all appear possible. ...Synopsis... A negatively tilted upper trough with embedded 50-70 kt mid-level speed maximum will eject northeastward across the northern/central Plains on Monday. At the surface, the primary low should consolidate over the northern High Plains of eastern MT/western ND and vicinity, with a secondary surface low possibly developing over the central High Plains by Monday evening. A rather moist low-level airmass, with surface dewpoints generally in the mid 60s to low 70s, will spread northward across the southern/central Plains ahead of an eastward-mixing dryline. A warm front should eventually extend eastward across parts of NE/IA, and this boundary will probably be the northern limit of appreciable severe-thunderstorm potential. ...Southern/Central Plains... A severe-weather outbreak still appears possible across parts of the southern/central Plains on Monday, focused from south-central/ southeast NE into central/eastern KS and much of OK. Robust diurnal heating of the moist low-level airmass, coupled with steep mid-level lapse rates overspreading much of the warm sector, will likely foster moderate to strong instability (MLCAPE generally ranging from 2000-3500 J/kg) by Monday afternoon. Enhanced mid-level winds and a favorably veering/strengthening wind profile with height through mid/upper levels will support around 40-55 kt of effective bulk shear, stronger with northward extent in KS/NE. Current expectations are for scattered supercells to erupt along the length of the dryline in south-central NE and western/central KS by mid to late Monday afternoon, coincident with stronger large-scale ascent overspreading this region. Given the rather favorable thermodynamic and kinematic parameter space, very large to giant hail (2-4 inch diameter) will likely be a threat with these initial supercells. The threat for tornadoes should quickly increase through the late afternoon and early evening in tandem with a strengthening southerly low-level jet. Ample 0-1 km and effective SRH shown in various NAM/GFS forecast soundings suggest a threat for strong tornadoes with any supercell that can remain discrete. With time Monday evening and into early Tuesday morning, upscale growth into multiple linear structures is probable, with an increased threat for severe/damaging winds, along with embedded tornadoes given the forecast strength of the low-level shear. The southward extent of the substantial severe risk into OK and north TX remains somewhat uncertain, as better forcing for ascent will tend to remain across the central Plains. Still, modest mid-level height falls should encourage isolated to perhaps widely scatted supercells developing along the length of the dryline into the southern Plains. Very large hail and strong tornadoes will be the main threats with any supercell that can develop and persist across this region Monday afternoon/evening. Model trends will also be monitored for a more favorable corridor of strong tornadoes and giant hail, which may necessitate greater severe probabilities for Monday in a later outlook. ..Gleason.. 05/04/2024 Read more

MD 0627 CONCERNING SEVERE THUNDERSTORM WATCH 182... FOR SOUTHEAST NEBRASKA...SOUTHWEST IOWA...NORTHWESTERN MISSOURI...NORTHEAST KANSAS
Mesoscale Discussion 0627 NWS Storm Prediction Center Norman OK 0102 AM CDT Sat May 04 2024 Areas affected...Southeast Nebraska...Southwest Iowa...Northwestern Missouri...Northeast Kansas Concerning...Severe Thunderstorm Watch 182... Valid 040602Z - 040800Z The severe weather threat for Severe Thunderstorm Watch 182 continues. SUMMARY...A wind-damage threat is expected to continue across parts of the lower to mid Missouri Valley tonight. A watch extension in area has been made for Cowley and Butler Counties in Kansas. However, the line is expected to become increasingly marginal over time, and new weather watch issuance is not expected to the east of WW 182. DISCUSSION...The latest hi-resolution radar from Hastings shows a large-scale bowing line segment across southeast Nebraska and north-central Kansas. This line of storms is located near a warm front, which extends east-southeastward into northern Missouri. From near and to the south of the front, surface dewpoints are in upper 50s and lower 60s F, with MLCAPE is in the 1000 to 1500 J/kg range. In addition, a shortwave trough is evident on water vapor imagery over central Kansas. Large-scale ascent associated with the shortwave and the instability will provide support for the ongoing linear MCS for a few more hours. Isolated damaging gusts will be possible along the leading edge of the MCS. However, as MLCIN strengthens across the central Plains and instability decreases, the wind-damage threat is expected to become more marginal with time. ..Broyles.. 05/04/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...EAX...OAX...TOP...ICT...GID... LAT...LON 39459466 39969433 40309425 40469436 40599469 40689618 40659680 40279733 39659798 39389816 39129808 39039744 39019585 39199505 39459466 Read more

MD 0626 CONCERNING SEVERE THUNDERSTORM WATCH 182... FOR SOUTH-CENTRAL KANSAS INTO THE NORTHWESTERN QUARTER OF OKLAHOMA
Mesoscale Discussion 0626 NWS Storm Prediction Center Norman OK 1141 PM CDT Fri May 03 2024 Areas affected...south-central Kansas into the northwestern quarter of Oklahoma Concerning...Severe Thunderstorm Watch 182... Valid 040441Z - 040615Z The severe weather threat for Severe Thunderstorm Watch 182 continues. SUMMARY...Risk for locally damaging wind gusts continues across portions of south-central Kansas and adjacent northwestern Oklahoma. DISCUSSION...Latest radar loop shows bands/clusters of organized storms moving eastward across the southern half of WW 182. Ample instability exists ahead of the convection, given the degree of organization, to support continuation of the storms over the next couple of hours -- particularly given ascent associated with warm advection as a result of the observed 50 kt low-level jet. While mid-level flow remains rather weak across the area, storms continue to advance steadily eastward in tandem with rather well-defined outflow, and will be accompanied by at least local risk for wind gusts near or slightly exceeding severe levels. ..Goss.. 05/04/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...OUN...DDC... LAT...LON 35529989 36129911 36569921 36749910 36969929 37449863 37669861 37459823 36679773 35879790 35429802 35529989 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat May 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX AND LOWER MISSISSIPPI VALLEY...AND PORTIONS OF OHIO INTO WESTERN PENNSYLVANIA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Sunday across parts of the southern Plains into the ArkLaTex and lower Mississippi Valley, and separately over portions of Ohio into western Pennsylvania. ...Synopsis... A pronounced/deep closed upper low over CA/NV will move eastward over the western states on Sunday, eventually transitioning into an open wave as it overspreads the northern/central Rockies by early Monday morning. A weak southern-stream shortwave trough is forecast to move northeastward from the southern Plains to the ArkLaTex and lower MS Valley through the day. Another upper trough over Ontario is expected to advance into Quebec, with the southern portion of this feature glancing the lower Great Lakes and vicinity. Surface lee cyclogenesis will occur across the northern High Plains ahead of the western CONUS upper trough/low. Rich low-level moisture should advance northward across the southern/central Plains through the period, although convection over TX may temporarily slow this process. ...Southern Plains into the ArkLaTex/Lower Mississippi Valley... Multiple thunderstorm clusters will probably be ongoing across parts of west into central TX at the start of the period Sunday morning. An isolated threat for damaging winds and hail may persist with this activity as it spreads eastward towards the middle/upper TX Coast through early Sunday afternoon. A gradual uptick in convective coverage and intensity may occur as modest destabilization occurs ahead of ongoing thunderstorms. Strong deep-layer shear should support continued convective organization, with small bowing clusters possible. Isolated strong to severe thunderstorms may also occur across parts of the ArkLaTex into the lower MS Valley as a weak shortwave trough moves across these regions through Sunday afternoon. However, effective bulk shear should remain weaker over these areas. Based on the likelihood and probable placement of morning convection across central TX, have expanded the Marginal Risk a bit southward/eastward, while also trimming much of north TX and south-central OK out of severe probabilities. ...Ohio into Western Pennsylvania... Modest destabilization should occur ahead of a weak front advancing east-southeastward across the OH Valley on Sunday. Isolated to scattered thunderstorms should develop by Sunday afternoon along or just ahead of this boundary, as weak large-scale ascent associated with an upper trough over Ontario/Quebec overspreads this region. Deep-layer shear of 20-30 kt should support marginal updraft organization. Occasional strong to damaging winds may occur with any small clusters that can consolidate and spread east-southeastward across parts of OH into western PA and vicinity Sunday afternoon and early evening. This activity should gradually weaken through the evening across PA as it encounters a less unstable airmass. ...Northern High Plains... Low-level moisture is expected to remain very shallow/meager across the northern High Plains through the period. Even so, daytime heating and steep mid-level lapse rates may still support weak instability developing through Sunday afternoon along/east of the sharpening surface lee trough. While isolated high-based convection that develops across this region could produce locally strong/gusty winds, the overall severe threat appears too limited to include low severe probabilities at this time. ..Gleason.. 05/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat May 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX AND LOWER MISSISSIPPI VALLEY...AND PORTIONS OF OHIO INTO WESTERN PENNSYLVANIA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Sunday across parts of the southern Plains into the ArkLaTex and lower Mississippi Valley, and separately over portions of Ohio into western Pennsylvania. ...Synopsis... A pronounced/deep closed upper low over CA/NV will move eastward over the western states on Sunday, eventually transitioning into an open wave as it overspreads the northern/central Rockies by early Monday morning. A weak southern-stream shortwave trough is forecast to move northeastward from the southern Plains to the ArkLaTex and lower MS Valley through the day. Another upper trough over Ontario is expected to advance into Quebec, with the southern portion of this feature glancing the lower Great Lakes and vicinity. Surface lee cyclogenesis will occur across the northern High Plains ahead of the western CONUS upper trough/low. Rich low-level moisture should advance northward across the southern/central Plains through the period, although convection over TX may temporarily slow this process. ...Southern Plains into the ArkLaTex/Lower Mississippi Valley... Multiple thunderstorm clusters will probably be ongoing across parts of west into central TX at the start of the period Sunday morning. An isolated threat for damaging winds and hail may persist with this activity as it spreads eastward towards the middle/upper TX Coast through early Sunday afternoon. A gradual uptick in convective coverage and intensity may occur as modest destabilization occurs ahead of ongoing thunderstorms. Strong deep-layer shear should support continued convective organization, with small bowing clusters possible. Isolated strong to severe thunderstorms may also occur across parts of the ArkLaTex into the lower MS Valley as a weak shortwave trough moves across these regions through Sunday afternoon. However, effective bulk shear should remain weaker over these areas. Based on the likelihood and probable placement of morning convection across central TX, have expanded the Marginal Risk a bit southward/eastward, while also trimming much of north TX and south-central OK out of severe probabilities. ...Ohio into Western Pennsylvania... Modest destabilization should occur ahead of a weak front advancing east-southeastward across the OH Valley on Sunday. Isolated to scattered thunderstorms should develop by Sunday afternoon along or just ahead of this boundary, as weak large-scale ascent associated with an upper trough over Ontario/Quebec overspreads this region. Deep-layer shear of 20-30 kt should support marginal updraft organization. Occasional strong to damaging winds may occur with any small clusters that can consolidate and spread east-southeastward across parts of OH into western PA and vicinity Sunday afternoon and early evening. This activity should gradually weaken through the evening across PA as it encounters a less unstable airmass. ...Northern High Plains... Low-level moisture is expected to remain very shallow/meager across the northern High Plains through the period. Even so, daytime heating and steep mid-level lapse rates may still support weak instability developing through Sunday afternoon along/east of the sharpening surface lee trough. While isolated high-based convection that develops across this region could produce locally strong/gusty winds, the overall severe threat appears too limited to include low severe probabilities at this time. ..Gleason.. 05/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat May 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX AND LOWER MISSISSIPPI VALLEY...AND PORTIONS OF OHIO INTO WESTERN PENNSYLVANIA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Sunday across parts of the southern Plains into the ArkLaTex and lower Mississippi Valley, and separately over portions of Ohio into western Pennsylvania. ...Synopsis... A pronounced/deep closed upper low over CA/NV will move eastward over the western states on Sunday, eventually transitioning into an open wave as it overspreads the northern/central Rockies by early Monday morning. A weak southern-stream shortwave trough is forecast to move northeastward from the southern Plains to the ArkLaTex and lower MS Valley through the day. Another upper trough over Ontario is expected to advance into Quebec, with the southern portion of this feature glancing the lower Great Lakes and vicinity. Surface lee cyclogenesis will occur across the northern High Plains ahead of the western CONUS upper trough/low. Rich low-level moisture should advance northward across the southern/central Plains through the period, although convection over TX may temporarily slow this process. ...Southern Plains into the ArkLaTex/Lower Mississippi Valley... Multiple thunderstorm clusters will probably be ongoing across parts of west into central TX at the start of the period Sunday morning. An isolated threat for damaging winds and hail may persist with this activity as it spreads eastward towards the middle/upper TX Coast through early Sunday afternoon. A gradual uptick in convective coverage and intensity may occur as modest destabilization occurs ahead of ongoing thunderstorms. Strong deep-layer shear should support continued convective organization, with small bowing clusters possible. Isolated strong to severe thunderstorms may also occur across parts of the ArkLaTex into the lower MS Valley as a weak shortwave trough moves across these regions through Sunday afternoon. However, effective bulk shear should remain weaker over these areas. Based on the likelihood and probable placement of morning convection across central TX, have expanded the Marginal Risk a bit southward/eastward, while also trimming much of north TX and south-central OK out of severe probabilities. ...Ohio into Western Pennsylvania... Modest destabilization should occur ahead of a weak front advancing east-southeastward across the OH Valley on Sunday. Isolated to scattered thunderstorms should develop by Sunday afternoon along or just ahead of this boundary, as weak large-scale ascent associated with an upper trough over Ontario/Quebec overspreads this region. Deep-layer shear of 20-30 kt should support marginal updraft organization. Occasional strong to damaging winds may occur with any small clusters that can consolidate and spread east-southeastward across parts of OH into western PA and vicinity Sunday afternoon and early evening. This activity should gradually weaken through the evening across PA as it encounters a less unstable airmass. ...Northern High Plains... Low-level moisture is expected to remain very shallow/meager across the northern High Plains through the period. Even so, daytime heating and steep mid-level lapse rates may still support weak instability developing through Sunday afternoon along/east of the sharpening surface lee trough. While isolated high-based convection that develops across this region could produce locally strong/gusty winds, the overall severe threat appears too limited to include low severe probabilities at this time. ..Gleason.. 05/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat May 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX AND LOWER MISSISSIPPI VALLEY...AND PORTIONS OF OHIO INTO WESTERN PENNSYLVANIA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Sunday across parts of the southern Plains into the ArkLaTex and lower Mississippi Valley, and separately over portions of Ohio into western Pennsylvania. ...Synopsis... A pronounced/deep closed upper low over CA/NV will move eastward over the western states on Sunday, eventually transitioning into an open wave as it overspreads the northern/central Rockies by early Monday morning. A weak southern-stream shortwave trough is forecast to move northeastward from the southern Plains to the ArkLaTex and lower MS Valley through the day. Another upper trough over Ontario is expected to advance into Quebec, with the southern portion of this feature glancing the lower Great Lakes and vicinity. Surface lee cyclogenesis will occur across the northern High Plains ahead of the western CONUS upper trough/low. Rich low-level moisture should advance northward across the southern/central Plains through the period, although convection over TX may temporarily slow this process. ...Southern Plains into the ArkLaTex/Lower Mississippi Valley... Multiple thunderstorm clusters will probably be ongoing across parts of west into central TX at the start of the period Sunday morning. An isolated threat for damaging winds and hail may persist with this activity as it spreads eastward towards the middle/upper TX Coast through early Sunday afternoon. A gradual uptick in convective coverage and intensity may occur as modest destabilization occurs ahead of ongoing thunderstorms. Strong deep-layer shear should support continued convective organization, with small bowing clusters possible. Isolated strong to severe thunderstorms may also occur across parts of the ArkLaTex into the lower MS Valley as a weak shortwave trough moves across these regions through Sunday afternoon. However, effective bulk shear should remain weaker over these areas. Based on the likelihood and probable placement of morning convection across central TX, have expanded the Marginal Risk a bit southward/eastward, while also trimming much of north TX and south-central OK out of severe probabilities. ...Ohio into Western Pennsylvania... Modest destabilization should occur ahead of a weak front advancing east-southeastward across the OH Valley on Sunday. Isolated to scattered thunderstorms should develop by Sunday afternoon along or just ahead of this boundary, as weak large-scale ascent associated with an upper trough over Ontario/Quebec overspreads this region. Deep-layer shear of 20-30 kt should support marginal updraft organization. Occasional strong to damaging winds may occur with any small clusters that can consolidate and spread east-southeastward across parts of OH into western PA and vicinity Sunday afternoon and early evening. This activity should gradually weaken through the evening across PA as it encounters a less unstable airmass. ...Northern High Plains... Low-level moisture is expected to remain very shallow/meager across the northern High Plains through the period. Even so, daytime heating and steep mid-level lapse rates may still support weak instability developing through Sunday afternoon along/east of the sharpening surface lee trough. While isolated high-based convection that develops across this region could produce locally strong/gusty winds, the overall severe threat appears too limited to include low severe probabilities at this time. ..Gleason.. 05/04/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat May 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX AND LOWER MISSISSIPPI VALLEY...AND PORTIONS OF OHIO INTO WESTERN PENNSYLVANIA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Sunday across parts of the southern Plains into the ArkLaTex and lower Mississippi Valley, and separately over portions of Ohio into western Pennsylvania. ...Synopsis... A pronounced/deep closed upper low over CA/NV will move eastward over the western states on Sunday, eventually transitioning into an open wave as it overspreads the northern/central Rockies by early Monday morning. A weak southern-stream shortwave trough is forecast to move northeastward from the southern Plains to the ArkLaTex and lower MS Valley through the day. Another upper trough over Ontario is expected to advance into Quebec, with the southern portion of this feature glancing the lower Great Lakes and vicinity. Surface lee cyclogenesis will occur across the northern High Plains ahead of the western CONUS upper trough/low. Rich low-level moisture should advance northward across the southern/central Plains through the period, although convection over TX may temporarily slow this process. ...Southern Plains into the ArkLaTex/Lower Mississippi Valley... Multiple thunderstorm clusters will probably be ongoing across parts of west into central TX at the start of the period Sunday morning. An isolated threat for damaging winds and hail may persist with this activity as it spreads eastward towards the middle/upper TX Coast through early Sunday afternoon. A gradual uptick in convective coverage and intensity may occur as modest destabilization occurs ahead of ongoing thunderstorms. Strong deep-layer shear should support continued convective organization, with small bowing clusters possible. Isolated strong to severe thunderstorms may also occur across parts of the ArkLaTex into the lower MS Valley as a weak shortwave trough moves across these regions through Sunday afternoon. However, effective bulk shear should remain weaker over these areas. Based on the likelihood and probable placement of morning convection across central TX, have expanded the Marginal Risk a bit southward/eastward, while also trimming much of north TX and south-central OK out of severe probabilities. ...Ohio into Western Pennsylvania... Modest destabilization should occur ahead of a weak front advancing east-southeastward across the OH Valley on Sunday. Isolated to scattered thunderstorms should develop by Sunday afternoon along or just ahead of this boundary, as weak large-scale ascent associated with an upper trough over Ontario/Quebec overspreads this region. Deep-layer shear of 20-30 kt should support marginal updraft organization. Occasional strong to damaging winds may occur with any small clusters that can consolidate and spread east-southeastward across parts of OH into western PA and vicinity Sunday afternoon and early evening. This activity should gradually weaken through the evening across PA as it encounters a less unstable airmass. ...Northern High Plains... Low-level moisture is expected to remain very shallow/meager across the northern High Plains through the period. Even so, daytime heating and steep mid-level lapse rates may still support weak instability developing through Sunday afternoon along/east of the sharpening surface lee trough. While isolated high-based convection that develops across this region could produce locally strong/gusty winds, the overall severe threat appears too limited to include low severe probabilities at this time. ..Gleason.. 05/04/2024 Read more