Aggregator

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Wed May 22 2024 Valid 221300Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL TEXAS TO CENTRAL ARKANSAS... ...SUMMARY... Within a long swath of severe-thunderstorm potential from central Texas to the Lower Great Lakes, the greatest concentration of severe weather (mainly large hail and damaging wind) should be across parts of central Texas to central Arkansas. A few tornadoes are also possible. ...Synopsis... An active mid/upper-level pattern persists southeast through southwest of a longstanding cyclone over southern SK and paths of southern MB. That circulation will continue to meander erratically near its present location through the period. Meanwhile, a train of shortwaves will cross the northwestern and central CONUS and Great Lakes regions. A strong shortwave trough -- with embedded 500-mb low now over ON near the MN border -- should become stacked with its deep surface cyclone this morning and drift erratically over ON northwest of Lake Superior today. The stacked low then should eject toward James Bay tonight. The associated cold front -- analyzed at 11Z from northern Lower MI to southern IL, northwestern AR, southern OK, and northwest TX to the Permian Basin -- should move by 00Z to near a line from CLE-EVV-ARG-DUA-SJT-CNM. The cold front should cross the lower Great Lakes and much of NY through the end of the period, while decelerating across parts of the lower/middle Ohio Valley. The western part of the front should become more diffuse and retreat northward overnight across the southern Plains. This will occur as low-level mass response (including warm advection) intensifies, ahead of a mid/upper cyclone moving eastward across the northwestern CONUS toward the western WY/eastern ID region. A dryline -- initially drawn over the Big Bend region south of the front -- should mix eastward to northern Coahuila and a frontal intersection over west-central TX by mid/late afternoon. ...Southern Plains to Arklatex region... A broken swath of elevated thunderstorms is ongoing over parts of central OK to southeastern KS. Isolated large hail is the main concern, and should be for a few more hours. Some of this activity may aggregate into a broader belt or cluster of convection and shift eastward to southeastward through the day, toward the front. Additional thunderstorms should develop from midday through this afternoon along/ahead of the front and mid/late afternoon near the dryline, with the near-frontal activity having the longest and strongest organizational potential. A few supercells are expected early in the convective cycle, and any supercell that stays relatively discrete well into maturity will pose a risk of large to giant hail. Storm-scale/boundary processes also may locally boost tornado potential. Activity should grow upscale into the evening -- perhaps merging with remnants of earlier activity moving southeastward from OK toward the surface front. As this occurs, the main threat will transition to damaging and severe gusts. The "enhanced" area represents the overlap of greatest hail and wind probabilities with this transitional regime. The warm sector southeast of the front, and east of the dryline, will remain very moist -- characterized by upper 60s to mid 70s F surface dew points. Underlying steep midlevel lapse rates, and with strong surface heating anticipated, the result should be a corridor of 3000-4000 J/kg MLCAPE. Given the strong heating and high ambient theta-e, convective temperature may be attained even in the free warm sector (away from the front and dryline), and despite the prevalent EML. Though forecast soundings show weaknesses in the flow around 2-3 km, both low-level and deep-layer shear (effective- shear magnitudes 55-65 kt) and lengthy hodographs will be present, supporting potential for locally destructive hail. Severe downdrafts also are possible, both from individual supercells and from convection resulting from aggregated cold pools. The overall threat should decrease with this activity as it shifts eastward- southeastward toward south/east TX and over LA tonight. However, additional development atop the outflow may occur tonight farther north near the Red River, helping to maintain some severe threat (mainly in the form of hail and isolated severe gusts). ...Mid-South to Ohio Valley and lower Great Lakes... Widely scattered to scattered thunderstorms, some in clusters, are expected along this corridor from mid afternoon through the evening. Damaging gusts will be the main concern, with isolated large hail also possible. A marginal tornado threat also may develop, particularly over portions of central/eastern OH to northwestern PA and perhaps southwestern upstate NY, where low-level and deep shear will be most favorable. Once some ongoing clouds/precip over the Ohio Valley move away and break up, surface heating should destabilize the boundary layer, in concert with dewpoints commonly in the 60s F. This should yield a prefrontal corridor of MLCAPE ranging from near 3000 J/kg over parts of the Mid-South (where deep-layer lapse rates will be steepest) to around 1500 J/kg over the area adjoining the lower Great Lakes. 35-45-kt effective-shear magnitudes will support a mix of multicell and supercell modes, with upscale growth/clustering tending to limit duration of supercells. ..Edwards/Goss.. 05/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Wed May 22 2024 Valid 221300Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL TEXAS TO CENTRAL ARKANSAS... ...SUMMARY... Within a long swath of severe-thunderstorm potential from central Texas to the Lower Great Lakes, the greatest concentration of severe weather (mainly large hail and damaging wind) should be across parts of central Texas to central Arkansas. A few tornadoes are also possible. ...Synopsis... An active mid/upper-level pattern persists southeast through southwest of a longstanding cyclone over southern SK and paths of southern MB. That circulation will continue to meander erratically near its present location through the period. Meanwhile, a train of shortwaves will cross the northwestern and central CONUS and Great Lakes regions. A strong shortwave trough -- with embedded 500-mb low now over ON near the MN border -- should become stacked with its deep surface cyclone this morning and drift erratically over ON northwest of Lake Superior today. The stacked low then should eject toward James Bay tonight. The associated cold front -- analyzed at 11Z from northern Lower MI to southern IL, northwestern AR, southern OK, and northwest TX to the Permian Basin -- should move by 00Z to near a line from CLE-EVV-ARG-DUA-SJT-CNM. The cold front should cross the lower Great Lakes and much of NY through the end of the period, while decelerating across parts of the lower/middle Ohio Valley. The western part of the front should become more diffuse and retreat northward overnight across the southern Plains. This will occur as low-level mass response (including warm advection) intensifies, ahead of a mid/upper cyclone moving eastward across the northwestern CONUS toward the western WY/eastern ID region. A dryline -- initially drawn over the Big Bend region south of the front -- should mix eastward to northern Coahuila and a frontal intersection over west-central TX by mid/late afternoon. ...Southern Plains to Arklatex region... A broken swath of elevated thunderstorms is ongoing over parts of central OK to southeastern KS. Isolated large hail is the main concern, and should be for a few more hours. Some of this activity may aggregate into a broader belt or cluster of convection and shift eastward to southeastward through the day, toward the front. Additional thunderstorms should develop from midday through this afternoon along/ahead of the front and mid/late afternoon near the dryline, with the near-frontal activity having the longest and strongest organizational potential. A few supercells are expected early in the convective cycle, and any supercell that stays relatively discrete well into maturity will pose a risk of large to giant hail. Storm-scale/boundary processes also may locally boost tornado potential. Activity should grow upscale into the evening -- perhaps merging with remnants of earlier activity moving southeastward from OK toward the surface front. As this occurs, the main threat will transition to damaging and severe gusts. The "enhanced" area represents the overlap of greatest hail and wind probabilities with this transitional regime. The warm sector southeast of the front, and east of the dryline, will remain very moist -- characterized by upper 60s to mid 70s F surface dew points. Underlying steep midlevel lapse rates, and with strong surface heating anticipated, the result should be a corridor of 3000-4000 J/kg MLCAPE. Given the strong heating and high ambient theta-e, convective temperature may be attained even in the free warm sector (away from the front and dryline), and despite the prevalent EML. Though forecast soundings show weaknesses in the flow around 2-3 km, both low-level and deep-layer shear (effective- shear magnitudes 55-65 kt) and lengthy hodographs will be present, supporting potential for locally destructive hail. Severe downdrafts also are possible, both from individual supercells and from convection resulting from aggregated cold pools. The overall threat should decrease with this activity as it shifts eastward- southeastward toward south/east TX and over LA tonight. However, additional development atop the outflow may occur tonight farther north near the Red River, helping to maintain some severe threat (mainly in the form of hail and isolated severe gusts). ...Mid-South to Ohio Valley and lower Great Lakes... Widely scattered to scattered thunderstorms, some in clusters, are expected along this corridor from mid afternoon through the evening. Damaging gusts will be the main concern, with isolated large hail also possible. A marginal tornado threat also may develop, particularly over portions of central/eastern OH to northwestern PA and perhaps southwestern upstate NY, where low-level and deep shear will be most favorable. Once some ongoing clouds/precip over the Ohio Valley move away and break up, surface heating should destabilize the boundary layer, in concert with dewpoints commonly in the 60s F. This should yield a prefrontal corridor of MLCAPE ranging from near 3000 J/kg over parts of the Mid-South (where deep-layer lapse rates will be steepest) to around 1500 J/kg over the area adjoining the lower Great Lakes. 35-45-kt effective-shear magnitudes will support a mix of multicell and supercell modes, with upscale growth/clustering tending to limit duration of supercells. ..Edwards/Goss.. 05/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Wed May 22 2024 Valid 221300Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL TEXAS TO CENTRAL ARKANSAS... ...SUMMARY... Within a long swath of severe-thunderstorm potential from central Texas to the Lower Great Lakes, the greatest concentration of severe weather (mainly large hail and damaging wind) should be across parts of central Texas to central Arkansas. A few tornadoes are also possible. ...Synopsis... An active mid/upper-level pattern persists southeast through southwest of a longstanding cyclone over southern SK and paths of southern MB. That circulation will continue to meander erratically near its present location through the period. Meanwhile, a train of shortwaves will cross the northwestern and central CONUS and Great Lakes regions. A strong shortwave trough -- with embedded 500-mb low now over ON near the MN border -- should become stacked with its deep surface cyclone this morning and drift erratically over ON northwest of Lake Superior today. The stacked low then should eject toward James Bay tonight. The associated cold front -- analyzed at 11Z from northern Lower MI to southern IL, northwestern AR, southern OK, and northwest TX to the Permian Basin -- should move by 00Z to near a line from CLE-EVV-ARG-DUA-SJT-CNM. The cold front should cross the lower Great Lakes and much of NY through the end of the period, while decelerating across parts of the lower/middle Ohio Valley. The western part of the front should become more diffuse and retreat northward overnight across the southern Plains. This will occur as low-level mass response (including warm advection) intensifies, ahead of a mid/upper cyclone moving eastward across the northwestern CONUS toward the western WY/eastern ID region. A dryline -- initially drawn over the Big Bend region south of the front -- should mix eastward to northern Coahuila and a frontal intersection over west-central TX by mid/late afternoon. ...Southern Plains to Arklatex region... A broken swath of elevated thunderstorms is ongoing over parts of central OK to southeastern KS. Isolated large hail is the main concern, and should be for a few more hours. Some of this activity may aggregate into a broader belt or cluster of convection and shift eastward to southeastward through the day, toward the front. Additional thunderstorms should develop from midday through this afternoon along/ahead of the front and mid/late afternoon near the dryline, with the near-frontal activity having the longest and strongest organizational potential. A few supercells are expected early in the convective cycle, and any supercell that stays relatively discrete well into maturity will pose a risk of large to giant hail. Storm-scale/boundary processes also may locally boost tornado potential. Activity should grow upscale into the evening -- perhaps merging with remnants of earlier activity moving southeastward from OK toward the surface front. As this occurs, the main threat will transition to damaging and severe gusts. The "enhanced" area represents the overlap of greatest hail and wind probabilities with this transitional regime. The warm sector southeast of the front, and east of the dryline, will remain very moist -- characterized by upper 60s to mid 70s F surface dew points. Underlying steep midlevel lapse rates, and with strong surface heating anticipated, the result should be a corridor of 3000-4000 J/kg MLCAPE. Given the strong heating and high ambient theta-e, convective temperature may be attained even in the free warm sector (away from the front and dryline), and despite the prevalent EML. Though forecast soundings show weaknesses in the flow around 2-3 km, both low-level and deep-layer shear (effective- shear magnitudes 55-65 kt) and lengthy hodographs will be present, supporting potential for locally destructive hail. Severe downdrafts also are possible, both from individual supercells and from convection resulting from aggregated cold pools. The overall threat should decrease with this activity as it shifts eastward- southeastward toward south/east TX and over LA tonight. However, additional development atop the outflow may occur tonight farther north near the Red River, helping to maintain some severe threat (mainly in the form of hail and isolated severe gusts). ...Mid-South to Ohio Valley and lower Great Lakes... Widely scattered to scattered thunderstorms, some in clusters, are expected along this corridor from mid afternoon through the evening. Damaging gusts will be the main concern, with isolated large hail also possible. A marginal tornado threat also may develop, particularly over portions of central/eastern OH to northwestern PA and perhaps southwestern upstate NY, where low-level and deep shear will be most favorable. Once some ongoing clouds/precip over the Ohio Valley move away and break up, surface heating should destabilize the boundary layer, in concert with dewpoints commonly in the 60s F. This should yield a prefrontal corridor of MLCAPE ranging from near 3000 J/kg over parts of the Mid-South (where deep-layer lapse rates will be steepest) to around 1500 J/kg over the area adjoining the lower Great Lakes. 35-45-kt effective-shear magnitudes will support a mix of multicell and supercell modes, with upscale growth/clustering tending to limit duration of supercells. ..Edwards/Goss.. 05/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Wed May 22 2024 Valid 221300Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL TEXAS TO CENTRAL ARKANSAS... ...SUMMARY... Within a long swath of severe-thunderstorm potential from central Texas to the Lower Great Lakes, the greatest concentration of severe weather (mainly large hail and damaging wind) should be across parts of central Texas to central Arkansas. A few tornadoes are also possible. ...Synopsis... An active mid/upper-level pattern persists southeast through southwest of a longstanding cyclone over southern SK and paths of southern MB. That circulation will continue to meander erratically near its present location through the period. Meanwhile, a train of shortwaves will cross the northwestern and central CONUS and Great Lakes regions. A strong shortwave trough -- with embedded 500-mb low now over ON near the MN border -- should become stacked with its deep surface cyclone this morning and drift erratically over ON northwest of Lake Superior today. The stacked low then should eject toward James Bay tonight. The associated cold front -- analyzed at 11Z from northern Lower MI to southern IL, northwestern AR, southern OK, and northwest TX to the Permian Basin -- should move by 00Z to near a line from CLE-EVV-ARG-DUA-SJT-CNM. The cold front should cross the lower Great Lakes and much of NY through the end of the period, while decelerating across parts of the lower/middle Ohio Valley. The western part of the front should become more diffuse and retreat northward overnight across the southern Plains. This will occur as low-level mass response (including warm advection) intensifies, ahead of a mid/upper cyclone moving eastward across the northwestern CONUS toward the western WY/eastern ID region. A dryline -- initially drawn over the Big Bend region south of the front -- should mix eastward to northern Coahuila and a frontal intersection over west-central TX by mid/late afternoon. ...Southern Plains to Arklatex region... A broken swath of elevated thunderstorms is ongoing over parts of central OK to southeastern KS. Isolated large hail is the main concern, and should be for a few more hours. Some of this activity may aggregate into a broader belt or cluster of convection and shift eastward to southeastward through the day, toward the front. Additional thunderstorms should develop from midday through this afternoon along/ahead of the front and mid/late afternoon near the dryline, with the near-frontal activity having the longest and strongest organizational potential. A few supercells are expected early in the convective cycle, and any supercell that stays relatively discrete well into maturity will pose a risk of large to giant hail. Storm-scale/boundary processes also may locally boost tornado potential. Activity should grow upscale into the evening -- perhaps merging with remnants of earlier activity moving southeastward from OK toward the surface front. As this occurs, the main threat will transition to damaging and severe gusts. The "enhanced" area represents the overlap of greatest hail and wind probabilities with this transitional regime. The warm sector southeast of the front, and east of the dryline, will remain very moist -- characterized by upper 60s to mid 70s F surface dew points. Underlying steep midlevel lapse rates, and with strong surface heating anticipated, the result should be a corridor of 3000-4000 J/kg MLCAPE. Given the strong heating and high ambient theta-e, convective temperature may be attained even in the free warm sector (away from the front and dryline), and despite the prevalent EML. Though forecast soundings show weaknesses in the flow around 2-3 km, both low-level and deep-layer shear (effective- shear magnitudes 55-65 kt) and lengthy hodographs will be present, supporting potential for locally destructive hail. Severe downdrafts also are possible, both from individual supercells and from convection resulting from aggregated cold pools. The overall threat should decrease with this activity as it shifts eastward- southeastward toward south/east TX and over LA tonight. However, additional development atop the outflow may occur tonight farther north near the Red River, helping to maintain some severe threat (mainly in the form of hail and isolated severe gusts). ...Mid-South to Ohio Valley and lower Great Lakes... Widely scattered to scattered thunderstorms, some in clusters, are expected along this corridor from mid afternoon through the evening. Damaging gusts will be the main concern, with isolated large hail also possible. A marginal tornado threat also may develop, particularly over portions of central/eastern OH to northwestern PA and perhaps southwestern upstate NY, where low-level and deep shear will be most favorable. Once some ongoing clouds/precip over the Ohio Valley move away and break up, surface heating should destabilize the boundary layer, in concert with dewpoints commonly in the 60s F. This should yield a prefrontal corridor of MLCAPE ranging from near 3000 J/kg over parts of the Mid-South (where deep-layer lapse rates will be steepest) to around 1500 J/kg over the area adjoining the lower Great Lakes. 35-45-kt effective-shear magnitudes will support a mix of multicell and supercell modes, with upscale growth/clustering tending to limit duration of supercells. ..Edwards/Goss.. 05/22/2024 Read more

MD 0888 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF OKLAHOMA AND VICINITY
Mesoscale Discussion 0888 NWS Storm Prediction Center Norman OK 0537 AM CDT Wed May 22 2024 Areas affected...portions of Oklahoma and vicinity Concerning...Severe potential...Watch possible Valid 221037Z - 221230Z Probability of Watch Issuance...40 percent SUMMARY...Storm development is forecast to increase over the next couple of hours, with a few stronger storms likely to evolve with time. Risk for large hail is expected with a few of the strongest cells, which could require eventual consideration of WW issuance. DISCUSSION...Latest radar loop shows isolated convection just beginning to develop across parts of Oklahoma, supporting consistent signal in successive HRRR runs that an early-morning convective event will evolve across the Oklahoma vicinity. The convection appears to be occurring near the 850mb manifestation of the low-level baroclinic zone, as air ascends isentropically atop to the boundary to its LFC. Model data indicates abundant CAPE atop a surface-based stable layer north of the surface baroclinic zone, that currently stretches from near RUE (Russellville AR) southwestward to near MEZ (Mena AR), and then west-southwestward across southern Oklahoma to near FDR (Frederick, OK). Given the thermodynamic support, expect a few vigorous updrafts to evolve, with intensity/organization aided by slightly veering/steadily increasing southwesterly flow with height through the cloud-bearing layer. Given this potential for a few elevated supercells, attendant risk for large hail is expected to evolve. While likely to remain isolated, storms could become sufficient in coverage to warrant potential WW issuance in the 1 to 2 hour time frame. ..Goss/Edwards.. 05/22/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SGF...TSA...OUN... LAT...LON 34809941 35149913 36389702 36809504 36549382 36039338 35159403 34469665 34459857 34809941 Read more

000
ABPZ20 KNHC 221118
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Wed May 22 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Kelly

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed May 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...Day 4/Sat - Central/Southern Plains to Mid-MS Valley... An upper shortwave trough over AZ/NM is forecast to spread eastward across the central/southern Plains to the Ozarks vicinity on Saturday. As this occurs, southwesterly mid/upper flow will increase. Height falls will induce surface cyclogenesis over western KS and the OK/TX Panhandles during the daytime. In response, a warm front will lift northward across central/eastern OK/KS and much of the Mid-MS Valley. A surface dryline will extend south from the surface low near the OK/TX border through evening. During the nighttime hours, the surface low is forecast to develop east/northeast into MO while a cold front overspreads parts of the central/southern Plains by Sunday morning. A very moist and unstable airmass will develop over the region as the warm front lifts north, allowing for strong destabilization. As large-scale ascent and vertical shear increase during the afternoon/evening, widespread thunderstorm development is expected. Initial supercells appear possible near the dryline and surface low over OK/KS. With time, an MCS may develop over part of the region and spread east into AR/MO during the evening/overnight hours. All severe hazards appear possible at this time, and higher probabilities may be needed in subsequent outlooks as mesoscale features become better resolved for highlighting any corridors of greater severe risk within the broader region. ...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys... A synoptically concerning pattern is evident on Sunday across a broad region of the central U.S. The upper trough from the Day 4/Sat period will continue to shift east across the Midwest on Sunday. This will allow strong mid/upper southwesterly flow to overspread the region as a deepening surface low moves from MO toward Lake Michigan. Strong to severe thunderstorms may be ongoing across parts of MO/the Ozarks vicinity. Ahead of this activity, a rapidly moistening boundary layer with upper 60s to low 70s F dewpoints is expected to envelop much of the Mid-MS/OH/TN Valleys. Strong destabilization and favorable vertical shear, along with an eastward-progressing cold front will support both supercell storms, and possibly a developing QLCS, capable of all hazards. While details regarding morning convection and storm mode remain somewhat uncertain, higher-end severe potential appears possible with this pattern across portions of the region from midday into the nighttime hours. ...Days 6-8/Mon-Wed... Spread among model guidance increases quite a bit by Monday. Some severe potential is possible anywhere from the Southern states to the Mid-Atlantic as the upper trough lifts east/northeast. However, details regarding storm evolution on Day 5/Sun into early Monday, along with differing evolution of the surface pattern by various guidance results in low predictability. By Tuesday and Wednesday, an upper ridge is expected to move from the western U.S. into the Plains. This should mostly shut down severe potential west of the MS River. Read more

MD 0887 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHEASTERN MISSOURI SOUTHWARD ACROSS CENTRAL ARKANSAS
Mesoscale Discussion 0887 NWS Storm Prediction Center Norman OK 0315 AM CDT Wed May 22 2024 Areas affected...southeastern Missouri southward across central Arkansas Concerning...Severe potential...Watch unlikely Valid 220815Z - 221015Z Probability of Watch Issuance...20 percent SUMMARY...Isolated/occasionally strong storms expected to continue over the next few hours. Isolated and marginal nature of the risk may preclude the need for serious WW consideration. DISCUSSION...Latest radar loop shows a vigorous storm which has evolved not far from Hot Springs/Mountain View Arkansas, within an axis of moderate instability near/ahead of the surface cold front, per RAP-based objective analysis. Farther northeastward within this same CAPE axis, a couple of stronger cells have evolved over southeastern Missouri. While isolated stronger storms will remain possible across this region over the next few hours, large-scale forcing for ascent remains subtle at best. Still, with southwesterly flow aloft increasing gradually with height, shear sufficient for multicell/weak supercell storms is evident, supporting isolated risk for hail in the inch to inch-and-a-half range with the strongest updrafts. At this time, the anticipated isolated nature of the risk appears likely to preclude the need for WW issuance. However, we will continue to monitor convective evolution for any signs that coverage may become greater than currently anticipated, which could warrant further consideration. ..Goss/Edwards.. 05/22/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...MEG...LZK...SGF...SHV... LAT...LON 34009311 34219399 34639403 35189300 35819235 36809129 37179016 36788963 36189095 35479147 35019116 34639116 34169178 33889244 34009311 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Wed May 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OKLAHOMA AND THE OZARKS NORTHWARD TO THE SOUTHERN LAKE MICHIGAN VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are possible on Friday from eastern Oklahoma and the Ozarks, northward to the southern Lake Michigan vicinity. ...Eastern OK to southern Lake Michigan Vicinity... Friday begins with shortwave upper ridging over the Upper Great Lakes vicinity. This ridge will dampen as it shifts east toward the lower Great Lakes and a shortwave upper trough over the northern Plains develops east to the Upper Midwest. To the south across the southern Plains to the TN Valley vicinity, low-amplitude westerly flow around 30-40 kt will prevail. At the surface, low pressure over the eastern Dakotas will lift northward into Manitoba/western Ontario while a cold front progresses eastward across the mid/upper MS Valley and portions of the Ozarks. A seasonally moist airmass will be in place with low to mid 60s F dewpoints across parts of the Lake Michigan vicinity, increasing with southwest extent into OK/AR (upper 60s/low 70s F). Moderate to strong destabilization is expected, aided by steepening midlevel lapse rates. While stronger large-scale ascent will be focused over the Upper Midwest, the progressive cold front will be a focus for thunderstorm development through the period. Vertical shear will be modest, with deep-layer flow mostly parallel to the front. Clusters of thunderstorms pose a risk for strong/damaging gusts and possibly hail. Given a lack of stronger height falls until the nighttime hours and limited large-scale ascent with southward extent, severe thunderstorm coverage and evolution is a bit uncertain. Greater severe probabilities may become necessary in later outlooks if a corridor of greater potential becomes apparent as mesoscale details become better resolved. ...TN Valley to the Carolinas... A very moist and unstable airmass will be in place on Friday. Low-amplitude westerly flow will overspread the region, with large-scale ascent somewhat nebulous. There is some potential that a convectively enhanced vorticity maxima from remnant convection in the Day 2/Thu period will float through westerly flow. If this occurs, this could provide a focus for more organized convection in a weakly sheared environment. Uncertainty and the conditional nature of the threat at this time frame precludes severe probabilities, but strong storms are a possibility. ..Leitman.. 05/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Wed May 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OKLAHOMA AND THE OZARKS NORTHWARD TO THE SOUTHERN LAKE MICHIGAN VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are possible on Friday from eastern Oklahoma and the Ozarks, northward to the southern Lake Michigan vicinity. ...Eastern OK to southern Lake Michigan Vicinity... Friday begins with shortwave upper ridging over the Upper Great Lakes vicinity. This ridge will dampen as it shifts east toward the lower Great Lakes and a shortwave upper trough over the northern Plains develops east to the Upper Midwest. To the south across the southern Plains to the TN Valley vicinity, low-amplitude westerly flow around 30-40 kt will prevail. At the surface, low pressure over the eastern Dakotas will lift northward into Manitoba/western Ontario while a cold front progresses eastward across the mid/upper MS Valley and portions of the Ozarks. A seasonally moist airmass will be in place with low to mid 60s F dewpoints across parts of the Lake Michigan vicinity, increasing with southwest extent into OK/AR (upper 60s/low 70s F). Moderate to strong destabilization is expected, aided by steepening midlevel lapse rates. While stronger large-scale ascent will be focused over the Upper Midwest, the progressive cold front will be a focus for thunderstorm development through the period. Vertical shear will be modest, with deep-layer flow mostly parallel to the front. Clusters of thunderstorms pose a risk for strong/damaging gusts and possibly hail. Given a lack of stronger height falls until the nighttime hours and limited large-scale ascent with southward extent, severe thunderstorm coverage and evolution is a bit uncertain. Greater severe probabilities may become necessary in later outlooks if a corridor of greater potential becomes apparent as mesoscale details become better resolved. ...TN Valley to the Carolinas... A very moist and unstable airmass will be in place on Friday. Low-amplitude westerly flow will overspread the region, with large-scale ascent somewhat nebulous. There is some potential that a convectively enhanced vorticity maxima from remnant convection in the Day 2/Thu period will float through westerly flow. If this occurs, this could provide a focus for more organized convection in a weakly sheared environment. Uncertainty and the conditional nature of the threat at this time frame precludes severe probabilities, but strong storms are a possibility. ..Leitman.. 05/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Wed May 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OKLAHOMA AND THE OZARKS NORTHWARD TO THE SOUTHERN LAKE MICHIGAN VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are possible on Friday from eastern Oklahoma and the Ozarks, northward to the southern Lake Michigan vicinity. ...Eastern OK to southern Lake Michigan Vicinity... Friday begins with shortwave upper ridging over the Upper Great Lakes vicinity. This ridge will dampen as it shifts east toward the lower Great Lakes and a shortwave upper trough over the northern Plains develops east to the Upper Midwest. To the south across the southern Plains to the TN Valley vicinity, low-amplitude westerly flow around 30-40 kt will prevail. At the surface, low pressure over the eastern Dakotas will lift northward into Manitoba/western Ontario while a cold front progresses eastward across the mid/upper MS Valley and portions of the Ozarks. A seasonally moist airmass will be in place with low to mid 60s F dewpoints across parts of the Lake Michigan vicinity, increasing with southwest extent into OK/AR (upper 60s/low 70s F). Moderate to strong destabilization is expected, aided by steepening midlevel lapse rates. While stronger large-scale ascent will be focused over the Upper Midwest, the progressive cold front will be a focus for thunderstorm development through the period. Vertical shear will be modest, with deep-layer flow mostly parallel to the front. Clusters of thunderstorms pose a risk for strong/damaging gusts and possibly hail. Given a lack of stronger height falls until the nighttime hours and limited large-scale ascent with southward extent, severe thunderstorm coverage and evolution is a bit uncertain. Greater severe probabilities may become necessary in later outlooks if a corridor of greater potential becomes apparent as mesoscale details become better resolved. ...TN Valley to the Carolinas... A very moist and unstable airmass will be in place on Friday. Low-amplitude westerly flow will overspread the region, with large-scale ascent somewhat nebulous. There is some potential that a convectively enhanced vorticity maxima from remnant convection in the Day 2/Thu period will float through westerly flow. If this occurs, this could provide a focus for more organized convection in a weakly sheared environment. Uncertainty and the conditional nature of the threat at this time frame precludes severe probabilities, but strong storms are a possibility. ..Leitman.. 05/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Wed May 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OKLAHOMA AND THE OZARKS NORTHWARD TO THE SOUTHERN LAKE MICHIGAN VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are possible on Friday from eastern Oklahoma and the Ozarks, northward to the southern Lake Michigan vicinity. ...Eastern OK to southern Lake Michigan Vicinity... Friday begins with shortwave upper ridging over the Upper Great Lakes vicinity. This ridge will dampen as it shifts east toward the lower Great Lakes and a shortwave upper trough over the northern Plains develops east to the Upper Midwest. To the south across the southern Plains to the TN Valley vicinity, low-amplitude westerly flow around 30-40 kt will prevail. At the surface, low pressure over the eastern Dakotas will lift northward into Manitoba/western Ontario while a cold front progresses eastward across the mid/upper MS Valley and portions of the Ozarks. A seasonally moist airmass will be in place with low to mid 60s F dewpoints across parts of the Lake Michigan vicinity, increasing with southwest extent into OK/AR (upper 60s/low 70s F). Moderate to strong destabilization is expected, aided by steepening midlevel lapse rates. While stronger large-scale ascent will be focused over the Upper Midwest, the progressive cold front will be a focus for thunderstorm development through the period. Vertical shear will be modest, with deep-layer flow mostly parallel to the front. Clusters of thunderstorms pose a risk for strong/damaging gusts and possibly hail. Given a lack of stronger height falls until the nighttime hours and limited large-scale ascent with southward extent, severe thunderstorm coverage and evolution is a bit uncertain. Greater severe probabilities may become necessary in later outlooks if a corridor of greater potential becomes apparent as mesoscale details become better resolved. ...TN Valley to the Carolinas... A very moist and unstable airmass will be in place on Friday. Low-amplitude westerly flow will overspread the region, with large-scale ascent somewhat nebulous. There is some potential that a convectively enhanced vorticity maxima from remnant convection in the Day 2/Thu period will float through westerly flow. If this occurs, this could provide a focus for more organized convection in a weakly sheared environment. Uncertainty and the conditional nature of the threat at this time frame precludes severe probabilities, but strong storms are a possibility. ..Leitman.. 05/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Wed May 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OKLAHOMA AND THE OZARKS NORTHWARD TO THE SOUTHERN LAKE MICHIGAN VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are possible on Friday from eastern Oklahoma and the Ozarks, northward to the southern Lake Michigan vicinity. ...Eastern OK to southern Lake Michigan Vicinity... Friday begins with shortwave upper ridging over the Upper Great Lakes vicinity. This ridge will dampen as it shifts east toward the lower Great Lakes and a shortwave upper trough over the northern Plains develops east to the Upper Midwest. To the south across the southern Plains to the TN Valley vicinity, low-amplitude westerly flow around 30-40 kt will prevail. At the surface, low pressure over the eastern Dakotas will lift northward into Manitoba/western Ontario while a cold front progresses eastward across the mid/upper MS Valley and portions of the Ozarks. A seasonally moist airmass will be in place with low to mid 60s F dewpoints across parts of the Lake Michigan vicinity, increasing with southwest extent into OK/AR (upper 60s/low 70s F). Moderate to strong destabilization is expected, aided by steepening midlevel lapse rates. While stronger large-scale ascent will be focused over the Upper Midwest, the progressive cold front will be a focus for thunderstorm development through the period. Vertical shear will be modest, with deep-layer flow mostly parallel to the front. Clusters of thunderstorms pose a risk for strong/damaging gusts and possibly hail. Given a lack of stronger height falls until the nighttime hours and limited large-scale ascent with southward extent, severe thunderstorm coverage and evolution is a bit uncertain. Greater severe probabilities may become necessary in later outlooks if a corridor of greater potential becomes apparent as mesoscale details become better resolved. ...TN Valley to the Carolinas... A very moist and unstable airmass will be in place on Friday. Low-amplitude westerly flow will overspread the region, with large-scale ascent somewhat nebulous. There is some potential that a convectively enhanced vorticity maxima from remnant convection in the Day 2/Thu period will float through westerly flow. If this occurs, this could provide a focus for more organized convection in a weakly sheared environment. Uncertainty and the conditional nature of the threat at this time frame precludes severe probabilities, but strong storms are a possibility. ..Leitman.. 05/22/2024 Read more