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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sat May 17 2025 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. ..Hart/Moore.. 05/17/2025 Read more

MD 0836 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR UPSTATE NEW YORK AND NORTHERN VERMONT
Mesoscale Discussion 0836 NWS Storm Prediction Center Norman OK 0636 AM CDT Sat May 17 2025 Areas affected...Upstate New York and northern Vermont Concerning...Severe potential...Watch unlikely Valid 171136Z - 171400Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorms will continue moving northeast this morning. Additional thunderstorms will develop later this morning and afternoon and a watch may eventually be needed. DISCUSSION...As a strong mid-level low slowly moves east across the Great Lakes today, multiple rounds of thunderstorms are anticipated across upstate New York, Vermont, and New Hampshire. These storms will be aided by increasing large-scale forcing from a number of sources: increasing upper-level divergence, lobes of positive vorticity advection, and the left exit region of a mid-level jet. As diurnal heating increases this morning, cold mid-level temperatures will overspread the region. This, coupled with surface dewpoints ranging from the mid 50Fs to mid 60Fs will result in a largely unstable, uncapped environment, primed for thunderstorm development in association with one of the myriad of large-scale forcing mechanisms. One such mechanism is already producing thunderstorms across far eastern portions of Lake Ontario. These thunderstorms should continue to rapidly move northeast into northern Vermont this morning. These thunderstorms will be capable of producing gusty winds and small hail. The likelihood for a watch in the short-term is relatively low. However, as instability increases, and more widespread forcing for ascent moves into the area, a watch or watches may be needed across portions of the area by midday into early afternoon. ..Marsh/Bunting.. 05/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BTV...ALY...BGM...BUF... LAT...LON 43927225 43087390 42527564 42277680 42567763 43377876 43787863 43687688 44287631 44637567 45097477 45097330 45147184 44537152 43927225 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

No watches are valid as of Sat May 17 13:12:01 UTC 2025.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 17 2025 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...Southern Plains Region... Water vapor imagery depicts a pronounced southern stream upper-level trough over the Baja Peninsula this morning, with evidence of a lead impulse approaching southwest TX. This leading impulse will contribute to ascent in the vicinity of a sharpening dryline across Western North Texas/Oklahoma by early afternoon. To the east of the dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is expected to develop given the moist low-level air mass and relatively cool mid-level thermal profiles. With negligible CINH by early/mid afternoon, thunderstorms are expected to develop along the dryline and move east/northeast into North Texas and southern Oklahoma. Supercells will be the dominant mode initially, with a risk for very large hail (in excess of 3.5 inches), and damaging gusts. Although low-level shear is not especially strong, some tornado risk will exist given the magnitude of instability and potential for storm-scale interactions. Eventual upscale growth into a severe MCS is expected as storms continue to move across North TX/southern OK this evening. Severe wind probabilities have been increased across the Enhanced Risk area for the expectation of a more concentrated corridor of damaging wind potential. Across central/northwest OK, a narrowing plume of instability will be present east of the dryline and south of an east-west oriented frontal boundary. Within this moist sector, strong to extreme instability and around 50 kts of deep-layer shear will support at least isolated supercell storm development this afternoon over central OK. Very large hail (3 inches or greater) will be possible, in addition to damaging gusts. Tornado risk will be dependent on storm interactions. Thunderstorm development over northwest OK is more uncertain, however should a storm develop a supercell mode will be favored with all hazards possible. ...Northeast... Strong mid-level height falls will spread across much of the northeastern U.S. today in response to the approaching Great Lakes upper low. Large-scale ascent will increase with as the left-exit region of the 500mb jet translates across PA. Scattered thunderstorms, including supercells, are expected to develop along/ahead of the synoptic cold front across upstate NY, with subsequent movement expected into western New England. Multiple rounds of thunderstorms are likely, with severe hail and winds as the primary risks. A tornado or two cannot be ruled out with any stronger and semi-discrete supercell. Please refer to Mesoscale Discussion 836 for additional details on short-term expectations. ...Northern Utah Vicinity... A Marginal Risk has been introduced across northern UT and vicinity given expected higher concentration of storms within a deeply-mixed boundary layer. Strong/severe gusts will be the primary severe risk. ...Lower Mississippi Valley/Southeast... Thunderstorms continue from central MS into the western Carolinas at 13z, with occasional pulses of strong/severe cells. Isolated stronger storms will remain possible as diurnal heating/destabilization takes place in the presence of ample shear for organized storms. However, with the line of convection oriented generally parallel to the shear vector, any severe risk should be isolated. Strong gusts will be the primary hazard. ..Bunting/Marsh.. 05/17/2025 Read more