Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Wed Jul 13 2022 Valid 131700Z - 141200Z The isolated dry-thunderstorm area has been expanded slightly westward, based on the latest guidance. Otherwise, no changes have been made. Near critical wind/RH still appears possible across parts of southwest into central/northeast NV, within a broader region of elevated conditions covering much of NV into southeast OR/southwest ID. See the previous discussion below for more details. ..Dean.. 07/13/2022 .PREV DISCUSSION... /ISSUED 0134 AM CDT Wed Jul 13 2022/ ...Synopsis... Fire weather concerns will linger across the Great Basin today due to a combination of hot, dry, and windy conditions as well as the potential for dry thunderstorms. Monsoonal moisture continues to spread northward into the Pacific Northwest and northern Rockies per morning water-vapor imagery. A weak impulse currently along the West Coast will propagate northeastward along the periphery of the stagnant Four Corners ridge, which will both induce a mid-level mass response across the Great Basin and provide lift for thunderstorms this afternoon. ...Nevada and adjacent states... The east/northeastward propagation of the weak West Coast impulse is expected to result in a modest mass response across the Great Basin with increasing southerly winds between 800-600 mb. This will aid in sustaining 15-20 mph winds through central NV with frequent gusts between 25-30 mph. The downslope trajectories off the southern Sierra Nevada coupled with warm temperatures will support 10-15% RH values by mid afternoon across much of the region. While elevated conditions are expected across much of NV, the greatest fire-weather concern will likely reside across central to northeastern NV under the axis of stronger mid-level winds. This zone will see the greatest potential for critical conditions, through latest ensemble guidance continues to show only meager support for sustained critical conditions. ...Dry Thunderstorms... Monsoonal moisture was well sampled by 00 UTC soundings across the much of the western CONUS with PWATs ranging from 0.6-1.0 inch. Soundings from the Great Basin region, including LKN, SLC, and BOI, also sampled very dry boundary-layer conditions with mean RH between 15-30%. These conditions supported a mix of dry and wet thunderstorms yesterday (Tuesday), and are expected to largely remain in place for today. Lift ahead of the weak West Coast impulse, combined with orographic ascent, should result in another day of a wet/dry storm mixture across northeast NV into adjacent areas of UT and ID where fuels largely remain receptive and a weak QPF signal is noted in most guidance. A few dry thunderstorms are possible outside of this region to the north across the Pacific Northwest and into the northern Rockies where similar PWAT values are expected, but more marginal fuel status preludes a more expansive risk area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Wed Jul 13 2022 Valid 131700Z - 141200Z The isolated dry-thunderstorm area has been expanded slightly westward, based on the latest guidance. Otherwise, no changes have been made. Near critical wind/RH still appears possible across parts of southwest into central/northeast NV, within a broader region of elevated conditions covering much of NV into southeast OR/southwest ID. See the previous discussion below for more details. ..Dean.. 07/13/2022 .PREV DISCUSSION... /ISSUED 0134 AM CDT Wed Jul 13 2022/ ...Synopsis... Fire weather concerns will linger across the Great Basin today due to a combination of hot, dry, and windy conditions as well as the potential for dry thunderstorms. Monsoonal moisture continues to spread northward into the Pacific Northwest and northern Rockies per morning water-vapor imagery. A weak impulse currently along the West Coast will propagate northeastward along the periphery of the stagnant Four Corners ridge, which will both induce a mid-level mass response across the Great Basin and provide lift for thunderstorms this afternoon. ...Nevada and adjacent states... The east/northeastward propagation of the weak West Coast impulse is expected to result in a modest mass response across the Great Basin with increasing southerly winds between 800-600 mb. This will aid in sustaining 15-20 mph winds through central NV with frequent gusts between 25-30 mph. The downslope trajectories off the southern Sierra Nevada coupled with warm temperatures will support 10-15% RH values by mid afternoon across much of the region. While elevated conditions are expected across much of NV, the greatest fire-weather concern will likely reside across central to northeastern NV under the axis of stronger mid-level winds. This zone will see the greatest potential for critical conditions, through latest ensemble guidance continues to show only meager support for sustained critical conditions. ...Dry Thunderstorms... Monsoonal moisture was well sampled by 00 UTC soundings across the much of the western CONUS with PWATs ranging from 0.6-1.0 inch. Soundings from the Great Basin region, including LKN, SLC, and BOI, also sampled very dry boundary-layer conditions with mean RH between 15-30%. These conditions supported a mix of dry and wet thunderstorms yesterday (Tuesday), and are expected to largely remain in place for today. Lift ahead of the weak West Coast impulse, combined with orographic ascent, should result in another day of a wet/dry storm mixture across northeast NV into adjacent areas of UT and ID where fuels largely remain receptive and a weak QPF signal is noted in most guidance. A few dry thunderstorms are possible outside of this region to the north across the Pacific Northwest and into the northern Rockies where similar PWAT values are expected, but more marginal fuel status preludes a more expansive risk area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Wed Jul 13 2022 Valid 131700Z - 141200Z The isolated dry-thunderstorm area has been expanded slightly westward, based on the latest guidance. Otherwise, no changes have been made. Near critical wind/RH still appears possible across parts of southwest into central/northeast NV, within a broader region of elevated conditions covering much of NV into southeast OR/southwest ID. See the previous discussion below for more details. ..Dean.. 07/13/2022 .PREV DISCUSSION... /ISSUED 0134 AM CDT Wed Jul 13 2022/ ...Synopsis... Fire weather concerns will linger across the Great Basin today due to a combination of hot, dry, and windy conditions as well as the potential for dry thunderstorms. Monsoonal moisture continues to spread northward into the Pacific Northwest and northern Rockies per morning water-vapor imagery. A weak impulse currently along the West Coast will propagate northeastward along the periphery of the stagnant Four Corners ridge, which will both induce a mid-level mass response across the Great Basin and provide lift for thunderstorms this afternoon. ...Nevada and adjacent states... The east/northeastward propagation of the weak West Coast impulse is expected to result in a modest mass response across the Great Basin with increasing southerly winds between 800-600 mb. This will aid in sustaining 15-20 mph winds through central NV with frequent gusts between 25-30 mph. The downslope trajectories off the southern Sierra Nevada coupled with warm temperatures will support 10-15% RH values by mid afternoon across much of the region. While elevated conditions are expected across much of NV, the greatest fire-weather concern will likely reside across central to northeastern NV under the axis of stronger mid-level winds. This zone will see the greatest potential for critical conditions, through latest ensemble guidance continues to show only meager support for sustained critical conditions. ...Dry Thunderstorms... Monsoonal moisture was well sampled by 00 UTC soundings across the much of the western CONUS with PWATs ranging from 0.6-1.0 inch. Soundings from the Great Basin region, including LKN, SLC, and BOI, also sampled very dry boundary-layer conditions with mean RH between 15-30%. These conditions supported a mix of dry and wet thunderstorms yesterday (Tuesday), and are expected to largely remain in place for today. Lift ahead of the weak West Coast impulse, combined with orographic ascent, should result in another day of a wet/dry storm mixture across northeast NV into adjacent areas of UT and ID where fuels largely remain receptive and a weak QPF signal is noted in most guidance. A few dry thunderstorms are possible outside of this region to the north across the Pacific Northwest and into the northern Rockies where similar PWAT values are expected, but more marginal fuel status preludes a more expansive risk area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Wed Jul 13 2022 Valid 131700Z - 141200Z The isolated dry-thunderstorm area has been expanded slightly westward, based on the latest guidance. Otherwise, no changes have been made. Near critical wind/RH still appears possible across parts of southwest into central/northeast NV, within a broader region of elevated conditions covering much of NV into southeast OR/southwest ID. See the previous discussion below for more details. ..Dean.. 07/13/2022 .PREV DISCUSSION... /ISSUED 0134 AM CDT Wed Jul 13 2022/ ...Synopsis... Fire weather concerns will linger across the Great Basin today due to a combination of hot, dry, and windy conditions as well as the potential for dry thunderstorms. Monsoonal moisture continues to spread northward into the Pacific Northwest and northern Rockies per morning water-vapor imagery. A weak impulse currently along the West Coast will propagate northeastward along the periphery of the stagnant Four Corners ridge, which will both induce a mid-level mass response across the Great Basin and provide lift for thunderstorms this afternoon. ...Nevada and adjacent states... The east/northeastward propagation of the weak West Coast impulse is expected to result in a modest mass response across the Great Basin with increasing southerly winds between 800-600 mb. This will aid in sustaining 15-20 mph winds through central NV with frequent gusts between 25-30 mph. The downslope trajectories off the southern Sierra Nevada coupled with warm temperatures will support 10-15% RH values by mid afternoon across much of the region. While elevated conditions are expected across much of NV, the greatest fire-weather concern will likely reside across central to northeastern NV under the axis of stronger mid-level winds. This zone will see the greatest potential for critical conditions, through latest ensemble guidance continues to show only meager support for sustained critical conditions. ...Dry Thunderstorms... Monsoonal moisture was well sampled by 00 UTC soundings across the much of the western CONUS with PWATs ranging from 0.6-1.0 inch. Soundings from the Great Basin region, including LKN, SLC, and BOI, also sampled very dry boundary-layer conditions with mean RH between 15-30%. These conditions supported a mix of dry and wet thunderstorms yesterday (Tuesday), and are expected to largely remain in place for today. Lift ahead of the weak West Coast impulse, combined with orographic ascent, should result in another day of a wet/dry storm mixture across northeast NV into adjacent areas of UT and ID where fuels largely remain receptive and a weak QPF signal is noted in most guidance. A few dry thunderstorms are possible outside of this region to the north across the Pacific Northwest and into the northern Rockies where similar PWAT values are expected, but more marginal fuel status preludes a more expansive risk area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Wed Jul 13 2022 Valid 131700Z - 141200Z The isolated dry-thunderstorm area has been expanded slightly westward, based on the latest guidance. Otherwise, no changes have been made. Near critical wind/RH still appears possible across parts of southwest into central/northeast NV, within a broader region of elevated conditions covering much of NV into southeast OR/southwest ID. See the previous discussion below for more details. ..Dean.. 07/13/2022 .PREV DISCUSSION... /ISSUED 0134 AM CDT Wed Jul 13 2022/ ...Synopsis... Fire weather concerns will linger across the Great Basin today due to a combination of hot, dry, and windy conditions as well as the potential for dry thunderstorms. Monsoonal moisture continues to spread northward into the Pacific Northwest and northern Rockies per morning water-vapor imagery. A weak impulse currently along the West Coast will propagate northeastward along the periphery of the stagnant Four Corners ridge, which will both induce a mid-level mass response across the Great Basin and provide lift for thunderstorms this afternoon. ...Nevada and adjacent states... The east/northeastward propagation of the weak West Coast impulse is expected to result in a modest mass response across the Great Basin with increasing southerly winds between 800-600 mb. This will aid in sustaining 15-20 mph winds through central NV with frequent gusts between 25-30 mph. The downslope trajectories off the southern Sierra Nevada coupled with warm temperatures will support 10-15% RH values by mid afternoon across much of the region. While elevated conditions are expected across much of NV, the greatest fire-weather concern will likely reside across central to northeastern NV under the axis of stronger mid-level winds. This zone will see the greatest potential for critical conditions, through latest ensemble guidance continues to show only meager support for sustained critical conditions. ...Dry Thunderstorms... Monsoonal moisture was well sampled by 00 UTC soundings across the much of the western CONUS with PWATs ranging from 0.6-1.0 inch. Soundings from the Great Basin region, including LKN, SLC, and BOI, also sampled very dry boundary-layer conditions with mean RH between 15-30%. These conditions supported a mix of dry and wet thunderstorms yesterday (Tuesday), and are expected to largely remain in place for today. Lift ahead of the weak West Coast impulse, combined with orographic ascent, should result in another day of a wet/dry storm mixture across northeast NV into adjacent areas of UT and ID where fuels largely remain receptive and a weak QPF signal is noted in most guidance. A few dry thunderstorms are possible outside of this region to the north across the Pacific Northwest and into the northern Rockies where similar PWAT values are expected, but more marginal fuel status preludes a more expansive risk area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No Mesoscale Discussions are in effect as of Wed Jul 13 16:56:01 UTC 2022.

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jul 13 2022 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS PARTS OF MT AND MS/AL... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...MT this afternoon through late evening... A midlevel shortwave trough over WA/southern BC will brush western/northern MT while moving around the northwest periphery of the ridge over the Four Corners. Low-level moisture will be rather limited across MT this afternoon, but there will be sufficient midlevel moisture and surface heating/mixing for high-based convection this afternoon/evening. The more probable corridor for afternoon storm development will be by mid afternoon over the higher terrain of southwest MT, on the southeast edge of the more persistent clouds this morning across west central/northwest MT. The combination of deep inverted-v profiles and 35-50 kt midlevel flow will support storm clusters capable of producing severe outflow winds from southwest into north central MT this evening. ...Central MS/AL this afternoon... Clusters of thunderstorms are ongoing across northern MS along a slow-moving cold front, and a mesoscale outflow boundary is located farther south from west central AL into northeast MS. As surface temperatures warm into the 90s and dewpoints remain in the low-mid 70s, additional thunderstorm development is expected. Weak northwesterly-northerly midlevel flow suggests that the storm clusters should move slowly southeastward or southward, with a tendency for new storm development toward the southwest, in the direction of the maximum boundary-layer theta-e and largest buoyancy over central MS. ...Southeast Atlantic states this afternoon... A weak midlevel trough and belt of 30-50 kt midlevel flow is present from southeast GA across the coastal Carolinas. Pockets of surface heating to the southeast of a thicker cloud band will support scattered thunderstorm development this afternoon. Low-level lapse rates will not be particularly steep, but moderate buoyancy and the somewhat enhanced midlevel flow could support isolated damaging outflow gusts with multicell clusters. ...Northern OH and vicinity this afternoon... In association with a midlevel trough over southeast Lower MI, residual low-level moisture/daytime heating and weak buoyancy will support thunderstorm development this afternoon. Cool midlevel temperatures and effective bulk shear around 35 kt could support a few cells/clusters capable of producing marginally severe hail/wind. ..Thompson/Squitieri.. 07/13/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jul 13 2022 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS PARTS OF MT AND MS/AL... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...MT this afternoon through late evening... A midlevel shortwave trough over WA/southern BC will brush western/northern MT while moving around the northwest periphery of the ridge over the Four Corners. Low-level moisture will be rather limited across MT this afternoon, but there will be sufficient midlevel moisture and surface heating/mixing for high-based convection this afternoon/evening. The more probable corridor for afternoon storm development will be by mid afternoon over the higher terrain of southwest MT, on the southeast edge of the more persistent clouds this morning across west central/northwest MT. The combination of deep inverted-v profiles and 35-50 kt midlevel flow will support storm clusters capable of producing severe outflow winds from southwest into north central MT this evening. ...Central MS/AL this afternoon... Clusters of thunderstorms are ongoing across northern MS along a slow-moving cold front, and a mesoscale outflow boundary is located farther south from west central AL into northeast MS. As surface temperatures warm into the 90s and dewpoints remain in the low-mid 70s, additional thunderstorm development is expected. Weak northwesterly-northerly midlevel flow suggests that the storm clusters should move slowly southeastward or southward, with a tendency for new storm development toward the southwest, in the direction of the maximum boundary-layer theta-e and largest buoyancy over central MS. ...Southeast Atlantic states this afternoon... A weak midlevel trough and belt of 30-50 kt midlevel flow is present from southeast GA across the coastal Carolinas. Pockets of surface heating to the southeast of a thicker cloud band will support scattered thunderstorm development this afternoon. Low-level lapse rates will not be particularly steep, but moderate buoyancy and the somewhat enhanced midlevel flow could support isolated damaging outflow gusts with multicell clusters. ...Northern OH and vicinity this afternoon... In association with a midlevel trough over southeast Lower MI, residual low-level moisture/daytime heating and weak buoyancy will support thunderstorm development this afternoon. Cool midlevel temperatures and effective bulk shear around 35 kt could support a few cells/clusters capable of producing marginally severe hail/wind. ..Thompson/Squitieri.. 07/13/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jul 13 2022 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS PARTS OF MT AND MS/AL... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...MT this afternoon through late evening... A midlevel shortwave trough over WA/southern BC will brush western/northern MT while moving around the northwest periphery of the ridge over the Four Corners. Low-level moisture will be rather limited across MT this afternoon, but there will be sufficient midlevel moisture and surface heating/mixing for high-based convection this afternoon/evening. The more probable corridor for afternoon storm development will be by mid afternoon over the higher terrain of southwest MT, on the southeast edge of the more persistent clouds this morning across west central/northwest MT. The combination of deep inverted-v profiles and 35-50 kt midlevel flow will support storm clusters capable of producing severe outflow winds from southwest into north central MT this evening. ...Central MS/AL this afternoon... Clusters of thunderstorms are ongoing across northern MS along a slow-moving cold front, and a mesoscale outflow boundary is located farther south from west central AL into northeast MS. As surface temperatures warm into the 90s and dewpoints remain in the low-mid 70s, additional thunderstorm development is expected. Weak northwesterly-northerly midlevel flow suggests that the storm clusters should move slowly southeastward or southward, with a tendency for new storm development toward the southwest, in the direction of the maximum boundary-layer theta-e and largest buoyancy over central MS. ...Southeast Atlantic states this afternoon... A weak midlevel trough and belt of 30-50 kt midlevel flow is present from southeast GA across the coastal Carolinas. Pockets of surface heating to the southeast of a thicker cloud band will support scattered thunderstorm development this afternoon. Low-level lapse rates will not be particularly steep, but moderate buoyancy and the somewhat enhanced midlevel flow could support isolated damaging outflow gusts with multicell clusters. ...Northern OH and vicinity this afternoon... In association with a midlevel trough over southeast Lower MI, residual low-level moisture/daytime heating and weak buoyancy will support thunderstorm development this afternoon. Cool midlevel temperatures and effective bulk shear around 35 kt could support a few cells/clusters capable of producing marginally severe hail/wind. ..Thompson/Squitieri.. 07/13/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jul 13 2022 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS PARTS OF MT AND MS/AL... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...MT this afternoon through late evening... A midlevel shortwave trough over WA/southern BC will brush western/northern MT while moving around the northwest periphery of the ridge over the Four Corners. Low-level moisture will be rather limited across MT this afternoon, but there will be sufficient midlevel moisture and surface heating/mixing for high-based convection this afternoon/evening. The more probable corridor for afternoon storm development will be by mid afternoon over the higher terrain of southwest MT, on the southeast edge of the more persistent clouds this morning across west central/northwest MT. The combination of deep inverted-v profiles and 35-50 kt midlevel flow will support storm clusters capable of producing severe outflow winds from southwest into north central MT this evening. ...Central MS/AL this afternoon... Clusters of thunderstorms are ongoing across northern MS along a slow-moving cold front, and a mesoscale outflow boundary is located farther south from west central AL into northeast MS. As surface temperatures warm into the 90s and dewpoints remain in the low-mid 70s, additional thunderstorm development is expected. Weak northwesterly-northerly midlevel flow suggests that the storm clusters should move slowly southeastward or southward, with a tendency for new storm development toward the southwest, in the direction of the maximum boundary-layer theta-e and largest buoyancy over central MS. ...Southeast Atlantic states this afternoon... A weak midlevel trough and belt of 30-50 kt midlevel flow is present from southeast GA across the coastal Carolinas. Pockets of surface heating to the southeast of a thicker cloud band will support scattered thunderstorm development this afternoon. Low-level lapse rates will not be particularly steep, but moderate buoyancy and the somewhat enhanced midlevel flow could support isolated damaging outflow gusts with multicell clusters. ...Northern OH and vicinity this afternoon... In association with a midlevel trough over southeast Lower MI, residual low-level moisture/daytime heating and weak buoyancy will support thunderstorm development this afternoon. Cool midlevel temperatures and effective bulk shear around 35 kt could support a few cells/clusters capable of producing marginally severe hail/wind. ..Thompson/Squitieri.. 07/13/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jul 13 2022 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS PARTS OF MT AND MS/AL... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...MT this afternoon through late evening... A midlevel shortwave trough over WA/southern BC will brush western/northern MT while moving around the northwest periphery of the ridge over the Four Corners. Low-level moisture will be rather limited across MT this afternoon, but there will be sufficient midlevel moisture and surface heating/mixing for high-based convection this afternoon/evening. The more probable corridor for afternoon storm development will be by mid afternoon over the higher terrain of southwest MT, on the southeast edge of the more persistent clouds this morning across west central/northwest MT. The combination of deep inverted-v profiles and 35-50 kt midlevel flow will support storm clusters capable of producing severe outflow winds from southwest into north central MT this evening. ...Central MS/AL this afternoon... Clusters of thunderstorms are ongoing across northern MS along a slow-moving cold front, and a mesoscale outflow boundary is located farther south from west central AL into northeast MS. As surface temperatures warm into the 90s and dewpoints remain in the low-mid 70s, additional thunderstorm development is expected. Weak northwesterly-northerly midlevel flow suggests that the storm clusters should move slowly southeastward or southward, with a tendency for new storm development toward the southwest, in the direction of the maximum boundary-layer theta-e and largest buoyancy over central MS. ...Southeast Atlantic states this afternoon... A weak midlevel trough and belt of 30-50 kt midlevel flow is present from southeast GA across the coastal Carolinas. Pockets of surface heating to the southeast of a thicker cloud band will support scattered thunderstorm development this afternoon. Low-level lapse rates will not be particularly steep, but moderate buoyancy and the somewhat enhanced midlevel flow could support isolated damaging outflow gusts with multicell clusters. ...Northern OH and vicinity this afternoon... In association with a midlevel trough over southeast Lower MI, residual low-level moisture/daytime heating and weak buoyancy will support thunderstorm development this afternoon. Cool midlevel temperatures and effective bulk shear around 35 kt could support a few cells/clusters capable of producing marginally severe hail/wind. ..Thompson/Squitieri.. 07/13/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Wed Jul 13 2022 Valid 131300Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS WESTERN AND CENTRAL MONTANA...AS WELL AS PARTS OF MISSISSIPPI AND ALABAMA... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...Synopsis... A rather stagnant large-scale pattern will persist over the CONUS, characterized by mean troughing in the east, and ridging extending north-northeastward from an anchoring anticyclone over the Four Corners States. North of the high, some height falls are likely across the northern Rockies and High Plains, as weak perturbations eject northeastward through/from southwest flow ahead of a Pacific trough. downstream, two closely spaced shortwave troughs are apparent in moisture-channel imagery over: 1. Parts of Lower MI, and forecast to pivot across southern ON and OH by 18Z, then over the northern Appalachians this evening; 2. ON, between Lake Superior and James Bay, and forecast to move across eastern Lower MI, Lake Huron and adjoining areas of southwestern ON by 00Z, then pivot eastward to eastern ON and Lake Ontario overnight. The 11Z surface chart showed a slow-moving cold to quasistationary front near a line from ACK-PHL-LYH-CSV-BNA-MEM-DAL-MAF-TCS. This boundary should drift southeastward over the northern Tidewater region today, while remaining quasistationary elsewhere. A weak cold front -- related to the mid/upper troughing over the Upper Great Lakes region -- was drawn from southwestern QC across Lake Huron, central Lower MI, to near the IL/WI border. This boundary should move slowly southeastward through the period, reaching western portions of NY/PA, and southern parts of OH/IN/IL, by 12Z tomorrow. ...MT... Scattered thunderstorms are expected to develop this afternoon over higher terrain of western/southwestern MT, where MLCINH will be removed quickest by surface diabatic heating. This convection should move northeastward across the outlook area the remainder of the afternoon into early evening, offering occasional severe gusts (with isolated gusts near 75 mph possible). Morning dewpoints in the upper 40s to mid 50s over lower elevations will lessen through the afternoon as heating/mixing occurs. This should result in a very deep boundary layer characterized by nearly dry-adiabatic lapse rates, and dew points in the 30s to mid 40s -- still sufficient to support thunderstorms. In this profile, activity will be high-based, with substantial DCAPE (over 1000 J/kg) present over a broad area. The convective environment will be supported further by large-scale ascent preceding one of the subtle/ southwest-flow shortwave troughs, currently apparent over the northern NV/southern ID region. While isolated severe gusts may occur anywhere in a large swath of MT and northwestern WY, the greatest potential for clustering and cold-pool organization appears to be across the "slight" area. ...Southeast... Widely scattered to scattered thunderstorms -- some in locally dense multicellular clusters -- are possible this afternoon along/ahead of the cold front. Damaging to severe gusts should be the main concern. Initiating foci will include the front and prefrontal outflow/differential-heating boundaries, including an outflow boundary from prior/overnight convection, now evident over northern MS and northern/central AL. With one substantial mesoscale focus already readily apparent diagnostically, and a subtle boost to large-scale support (below), a relatively maximized area of convective-wind probabilities is evident over part of MS/AL that has improved in predictability since the previous outlook. The warm sector will remain characterized by rich moisture, with surface dew points in the upper 60s to mid 70s F, associated with areas of PW in the 2-2.25-inch range. A strip of sustained diurnal heating is likely -- between areas of ambient cloud cover, parallel to and ahead of the front -- which will overcome modest MLCINH and boost MLCAPE into the 1500-2500 J/kg range. Hail probabilities also have been added in and near the "slight" wind-threat area for today. Despite the weak low/level and deep shear, forecast soundings across portions of the area indicate a deep growth zone containing with abundant moisture and buoyancy, along with several 1-1.75-inch historic hail analogs in multiple locations' worth of sounding samples across the area. A little extra large-scale support for destabilization aloft also is evident on the southern rim of the right-entrance region of a cyclonically curved, 250-mb jet. An approximately southward-moving convective band is possible, yielding the most-concentrated severe potential. ...Northern OH/IN/southeastern MI... Isolated to scattered thunderstorms are expected to develop by late this afternoon, as the southern part of a mesoscale area of strong DCVA/ascent aloft moves over the region, ahead of the northern shortwave trough. This will steepen midlevel lapse rates that will have been poor for much of the afternoon, following the passage of the previous perturbation. As that occurs, marginal low-level moisture and associated buoyancy are expected, with MLCAPE generally in the 300-800 J/kg range (locally/briefly higher). A few downdrafts penetrating a well-mixed subcloud layer may produce damaging winds. The potential should be confined to just a few hours' time window around late-afternoon/early evening, before too much nocturnal near-surface stabilization occurs. The modest moisture and late timing of the strongest forcing for ascent preclude a better-organized severe threat. ..Edwards/Leitman.. 07/13/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Wed Jul 13 2022 Valid 131300Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS WESTERN AND CENTRAL MONTANA...AS WELL AS PARTS OF MISSISSIPPI AND ALABAMA... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...Synopsis... A rather stagnant large-scale pattern will persist over the CONUS, characterized by mean troughing in the east, and ridging extending north-northeastward from an anchoring anticyclone over the Four Corners States. North of the high, some height falls are likely across the northern Rockies and High Plains, as weak perturbations eject northeastward through/from southwest flow ahead of a Pacific trough. downstream, two closely spaced shortwave troughs are apparent in moisture-channel imagery over: 1. Parts of Lower MI, and forecast to pivot across southern ON and OH by 18Z, then over the northern Appalachians this evening; 2. ON, between Lake Superior and James Bay, and forecast to move across eastern Lower MI, Lake Huron and adjoining areas of southwestern ON by 00Z, then pivot eastward to eastern ON and Lake Ontario overnight. The 11Z surface chart showed a slow-moving cold to quasistationary front near a line from ACK-PHL-LYH-CSV-BNA-MEM-DAL-MAF-TCS. This boundary should drift southeastward over the northern Tidewater region today, while remaining quasistationary elsewhere. A weak cold front -- related to the mid/upper troughing over the Upper Great Lakes region -- was drawn from southwestern QC across Lake Huron, central Lower MI, to near the IL/WI border. This boundary should move slowly southeastward through the period, reaching western portions of NY/PA, and southern parts of OH/IN/IL, by 12Z tomorrow. ...MT... Scattered thunderstorms are expected to develop this afternoon over higher terrain of western/southwestern MT, where MLCINH will be removed quickest by surface diabatic heating. This convection should move northeastward across the outlook area the remainder of the afternoon into early evening, offering occasional severe gusts (with isolated gusts near 75 mph possible). Morning dewpoints in the upper 40s to mid 50s over lower elevations will lessen through the afternoon as heating/mixing occurs. This should result in a very deep boundary layer characterized by nearly dry-adiabatic lapse rates, and dew points in the 30s to mid 40s -- still sufficient to support thunderstorms. In this profile, activity will be high-based, with substantial DCAPE (over 1000 J/kg) present over a broad area. The convective environment will be supported further by large-scale ascent preceding one of the subtle/ southwest-flow shortwave troughs, currently apparent over the northern NV/southern ID region. While isolated severe gusts may occur anywhere in a large swath of MT and northwestern WY, the greatest potential for clustering and cold-pool organization appears to be across the "slight" area. ...Southeast... Widely scattered to scattered thunderstorms -- some in locally dense multicellular clusters -- are possible this afternoon along/ahead of the cold front. Damaging to severe gusts should be the main concern. Initiating foci will include the front and prefrontal outflow/differential-heating boundaries, including an outflow boundary from prior/overnight convection, now evident over northern MS and northern/central AL. With one substantial mesoscale focus already readily apparent diagnostically, and a subtle boost to large-scale support (below), a relatively maximized area of convective-wind probabilities is evident over part of MS/AL that has improved in predictability since the previous outlook. The warm sector will remain characterized by rich moisture, with surface dew points in the upper 60s to mid 70s F, associated with areas of PW in the 2-2.25-inch range. A strip of sustained diurnal heating is likely -- between areas of ambient cloud cover, parallel to and ahead of the front -- which will overcome modest MLCINH and boost MLCAPE into the 1500-2500 J/kg range. Hail probabilities also have been added in and near the "slight" wind-threat area for today. Despite the weak low/level and deep shear, forecast soundings across portions of the area indicate a deep growth zone containing with abundant moisture and buoyancy, along with several 1-1.75-inch historic hail analogs in multiple locations' worth of sounding samples across the area. A little extra large-scale support for destabilization aloft also is evident on the southern rim of the right-entrance region of a cyclonically curved, 250-mb jet. An approximately southward-moving convective band is possible, yielding the most-concentrated severe potential. ...Northern OH/IN/southeastern MI... Isolated to scattered thunderstorms are expected to develop by late this afternoon, as the southern part of a mesoscale area of strong DCVA/ascent aloft moves over the region, ahead of the northern shortwave trough. This will steepen midlevel lapse rates that will have been poor for much of the afternoon, following the passage of the previous perturbation. As that occurs, marginal low-level moisture and associated buoyancy are expected, with MLCAPE generally in the 300-800 J/kg range (locally/briefly higher). A few downdrafts penetrating a well-mixed subcloud layer may produce damaging winds. The potential should be confined to just a few hours' time window around late-afternoon/early evening, before too much nocturnal near-surface stabilization occurs. The modest moisture and late timing of the strongest forcing for ascent preclude a better-organized severe threat. ..Edwards/Leitman.. 07/13/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Wed Jul 13 2022 Valid 131300Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS WESTERN AND CENTRAL MONTANA...AS WELL AS PARTS OF MISSISSIPPI AND ALABAMA... ...SUMMARY... Thunderstorms capable of producing severe gusts and isolated hail will be most likely across western and central Montana, as well as parts of Mississippi and Alabama. ...Synopsis... A rather stagnant large-scale pattern will persist over the CONUS, characterized by mean troughing in the east, and ridging extending north-northeastward from an anchoring anticyclone over the Four Corners States. North of the high, some height falls are likely across the northern Rockies and High Plains, as weak perturbations eject northeastward through/from southwest flow ahead of a Pacific trough. downstream, two closely spaced shortwave troughs are apparent in moisture-channel imagery over: 1. Parts of Lower MI, and forecast to pivot across southern ON and OH by 18Z, then over the northern Appalachians this evening; 2. ON, between Lake Superior and James Bay, and forecast to move across eastern Lower MI, Lake Huron and adjoining areas of southwestern ON by 00Z, then pivot eastward to eastern ON and Lake Ontario overnight. The 11Z surface chart showed a slow-moving cold to quasistationary front near a line from ACK-PHL-LYH-CSV-BNA-MEM-DAL-MAF-TCS. This boundary should drift southeastward over the northern Tidewater region today, while remaining quasistationary elsewhere. A weak cold front -- related to the mid/upper troughing over the Upper Great Lakes region -- was drawn from southwestern QC across Lake Huron, central Lower MI, to near the IL/WI border. This boundary should move slowly southeastward through the period, reaching western portions of NY/PA, and southern parts of OH/IN/IL, by 12Z tomorrow. ...MT... Scattered thunderstorms are expected to develop this afternoon over higher terrain of western/southwestern MT, where MLCINH will be removed quickest by surface diabatic heating. This convection should move northeastward across the outlook area the remainder of the afternoon into early evening, offering occasional severe gusts (with isolated gusts near 75 mph possible). Morning dewpoints in the upper 40s to mid 50s over lower elevations will lessen through the afternoon as heating/mixing occurs. This should result in a very deep boundary layer characterized by nearly dry-adiabatic lapse rates, and dew points in the 30s to mid 40s -- still sufficient to support thunderstorms. In this profile, activity will be high-based, with substantial DCAPE (over 1000 J/kg) present over a broad area. The convective environment will be supported further by large-scale ascent preceding one of the subtle/ southwest-flow shortwave troughs, currently apparent over the northern NV/southern ID region. While isolated severe gusts may occur anywhere in a large swath of MT and northwestern WY, the greatest potential for clustering and cold-pool organization appears to be across the "slight" area. ...Southeast... Widely scattered to scattered thunderstorms -- some in locally dense multicellular clusters -- are possible this afternoon along/ahead of the cold front. Damaging to severe gusts should be the main concern. Initiating foci will include the front and prefrontal outflow/differential-heating boundaries, including an outflow boundary from prior/overnight convection, now evident over northern MS and northern/central AL. With one substantial mesoscale focus already readily apparent diagnostically, and a subtle boost to large-scale support (below), a relatively maximized area of convective-wind probabilities is evident over part of MS/AL that has improved in predictability since the previous outlook. The warm sector will remain characterized by rich moisture, with surface dew points in the upper 60s to mid 70s F, associated with areas of PW in the 2-2.25-inch range. A strip of sustained diurnal heating is likely -- between areas of ambient cloud cover, parallel to and ahead of the front -- which will overcome modest MLCINH and boost MLCAPE into the 1500-2500 J/kg range. Hail probabilities also have been added in and near the "slight" wind-threat area for today. Despite the weak low/level and deep shear, forecast soundings across portions of the area indicate a deep growth zone containing with abundant moisture and buoyancy, along with several 1-1.75-inch historic hail analogs in multiple locations' worth of sounding samples across the area. A little extra large-scale support for destabilization aloft also is evident on the southern rim of the right-entrance region of a cyclonically curved, 250-mb jet. An approximately southward-moving convective band is possible, yielding the most-concentrated severe potential. ...Northern OH/IN/southeastern MI... Isolated to scattered thunderstorms are expected to develop by late this afternoon, as the southern part of a mesoscale area of strong DCVA/ascent aloft moves over the region, ahead of the northern shortwave trough. This will steepen midlevel lapse rates that will have been poor for much of the afternoon, following the passage of the previous perturbation. As that occurs, marginal low-level moisture and associated buoyancy are expected, with MLCAPE generally in the 300-800 J/kg range (locally/briefly higher). A few downdrafts penetrating a well-mixed subcloud layer may produce damaging winds. The potential should be confined to just a few hours' time window around late-afternoon/early evening, before too much nocturnal near-surface stabilization occurs. The modest moisture and late timing of the strongest forcing for ascent preclude a better-organized severe threat. ..Edwards/Leitman.. 07/13/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Tue Jul 12 2022 Valid 121700Z - 131200Z The isolated dry-thunderstorm area has been expanded slightly northeast across northwest UT into far southern ID, based on the latest thunderstorm guidance. The Elevated area has been expanded westward across northeast CA into south-central OR, where sustained winds of 15-20 mph appear possible concurrent with minimum RH values of 15-20%. Otherwise, the previous reasoning remains valid. See the previous discussion below for more information. ..Dean.. 07/12/2022 .PREV DISCUSSION... /ISSUED 0111 AM CDT Tue Jul 12 2022/ ...Synopsis... Fire weather concerns will remain across the Great Basin for today and will likely emerge for portions of the northern Sierra into southern OR. Upper-level ridging over the Four Corners will continue to foster thunderstorm chances across the Great Basin. A thermal low over northern NV will support breezy conditions across southern portions of the state, while a weak mid-level wave will support windy conditions across parts of the Pacific Northwest. ...Nevada... Ensemble guidance continues to show fairly high probability in sustained winds between 15-20 mph across southern NV in response to the diurnal deepening of a thermal low to the north. Deep boundary-layer mixing may allow for a few gusts above 20 mph, but generally weak flow aloft will limit the potential for critical wind speeds. Poor moisture recovery and hot afternoon temperatures will support another day of RH values near 10-15%. This, combined with antecedent dry fuels, will support elevated fire weather conditions. ...Northern Sierra Nevada... Early-morning water vapor imagery reveals a mid-level impulse embedded within the mean southwesterly flow that is in place across the Pacific Northwest. This feature will not only support increasing thunderstorm chances across the region, but will also enhance boundary-layer flow across the northern Sierra Nevada into southern OR along and ahead of a surface trough. Most solutions suggest sustained winds between 15-20 mph will be common with locally stronger winds possible in the lee of terrain features. Dry fine fuels and afternoon RH values near 15-20% will support elevated fire weather conditions. ...Dry Thunderstorms... Monsoonal moisture lingers across the great Four Corners region and has increased across much of the Great Basin and West Coast per 00 UTC soundings. Most soundings continue to show sufficient mid-level moisture to support 100-250 J/kg MUCAPE atop deep, dry boundary layers. These thermodynamic profiles are expected to linger through the day (per forecast soundings) and will support dry thunderstorms across parts of the Great Basin, central Sierra Nevada, and across parts of the Pacific Northwest. While dry lightning is possible across all these regions, the risk area denotes locations where regional fuels are sufficiently dry to support a fire weather concern. Thunderstorms with occasional dry lightning are possible across central UT where fuels remain dry, but guidance remains consistent in showing a stronger QPF signal for today compared to previous days. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1455 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF WV INTO NORTHERN VA...WESTERN/CENTRAL MD...AND DC
Mesoscale Discussion 1455 NWS Storm Prediction Center Norman OK 1148 AM CDT Tue Jul 12 2022 Areas affected...Portions of WV into northern VA...western/central MD...and DC Concerning...Severe potential...Watch possible Valid 121648Z - 121915Z Probability of Watch Issuance...60 percent SUMMARY...A threat for scattered damaging winds and isolated hail should increase this afternoon. A Severe Thunderstorm Watch will probably be needed. DISCUSSION...A couple of thunderstorms have developed as of 1645Z near the OH/WV border. This activity is occurring just ahead of a weak surface cold front. These thunderstorms and additional convective development should spread eastward across much of WV through the afternoon. With robust diurnal heating occurring and the presence of modestly steepened mid-level lapse rates, around 1500-2000 J/kg of MLCAPE is expected to be present across the warm sector ahead of this activity. This region will be on the southern periphery of a strong mid-level jet over the Northeast, but modestly enhanced mid-level westerlies should still support around 30-40 kt of deep-layer shear. A mix of multicell clusters and marginal supercells should occur given the favorable shear. Thunderstorms may also develop along a pre-frontal trough over parts of northern VA/western MD and vicinity later this afternoon as residual convective inhibition eventually erodes. As low-level lapse rates steepen and DCAPE increases, damaging downdraft winds will become a concern as thunderstorms gradually increase in coverage and intensity. Some severe hail may also occur with any cells that can remain discrete given the modestly steepened mid-level lapse rates aloft. A Severe Thunderstorm Watch will probably be needed in the next couple of hours as more convection develops. ..Gleason/Thompson.. 07/12/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LWX...RNK...PBZ...RLX... LAT...LON 38378242 39578079 39717948 39717616 39507616 39027647 38587660 38377702 38147825 37837916 37678026 37618129 37808222 38378242 Read more

WW 0460 Status Updates
STATUS FOR WATCH 0460 HAS NOT BEEN ISSUED YET Read more

WW 460 SEVERE TSTM NY PA VT 121645Z - 122300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 460 NWS Storm Prediction Center Norman OK 1245 PM EDT Tue Jul 12 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central and northeast New York Northeast Pennsylvania Central and northern Vermont * Effective this Tuesday afternoon and evening from 1245 PM until 700 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible A tornado or two possible SUMMARY...Scattered severe thunderstorms are expected to form and move eastward, along and immediately east of a cold front. The storm environment will favor a mix of small clusters and some supercells capable of producing damaging outflow gusts and isolated large hail near 1 inch in diameter. An isolated tornado or two cannot be ruled out. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 35 miles north northwest of Burlington VT to 40 miles south southeast of Binghamton NY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27035. ...Thompson Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Tue Jul 12 2022 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC... ...SUMMARY... Thunderstorms, accompanied by a risk for damaging winds, are expected from New England through the Mid-Atlantic States into the central Appalachian region and Tennessee Valley, especially this afternoon and early evening. A few strong storms may also be noted across the Upper Midwest and over the central High Plains. ...Appalachians/Mid-Atlantic/Northeast this afternoon/evening... No changes to the previous outlook. Within a broad midlevel trough over the Great Lakes, an embedded speed maximum will eject eastward/northeastward from the central Appalachians/lower Great Lakes to the Mid-Atlantic and New England this afternoon/evening, as an associated surface cold front likewise moves eastward/southeastward from the upper OH Valley and western PA/NY. Destabilization will proceed from west-to-east through the afternoon in advance of the front in conjunction with low-level moisture advection and surface heating, and visible satellite imagery suggests that multiple cells/small clusters will form along and ahead of the cold front by early-mid afternoon from central PA/NY eastward. MLCAPE of 1000-2000 J/kg and relatively long/straight hodographs with effective bulk shear of 35-50 kt is expected from the Mid-Atlantic northward, along with DCAPE near 1000 J/kg. The near-storm environment and expected convective mode will favor clusters and supercells capable of producing damaging winds, though isolated large hail and an isolated tornado or two may also occur with the strongest storms. Some upscale growth into line segments will be possible, which would favor damaging winds as the primary threat. ...Ozarks to TN Valley this afternoon through late evening... Vertical shear will weaken with southwestward extent along a cold front moving slowly southward into TN/AR. Surface temperatures will warm into the 95-100 F range by late afternoon, with steep low-level lapse rates and moderate buoyancy immediately ahead of the front. Widely scattered thunderstorm development is expected by late afternoon/evening along the front, and the strongest storms will be capable of producing isolated strong/damaging downburst winds from late afternoon into this evening. ...Central High Plains this evening... Boundary-layer dewpoints in the mid-upper 50s reside across eastern CO as of mid morning, though some vertical mixing is expected this afternoon along with strong surface heating. A few high-based storms are expected to form late this afternoon/evening immediately east of the higher terrain, along a developing surface lee trough from southeast WY into northeast CO. Deep-layer northwesterly shear will be sufficient for some storm organization/supercell structures, while the steep lapse rates and modest buoyancy support the threat for isolated strong-severe outflow winds and marginally severe hail for a few hours late this afternoon/evening. ...MN/WI this afternoon/evening... An embedded shortwave trough will move southeastward from southern MB/far western ON across northern MN and WI through this evening. Surface heating and residual low-level moisture, beneath cool midlevel temperatures (near -15 C at 500 mb), will result in MLCAPE of 500-1000 J/kg this afternoon with minimal convective inhibition. Thus, scattered thunderstorm development is expected from northeast MN into northern WI, where the modest buoyancy and deep-layer west-northwesterly shear will be sufficient for clusters and low-end supercells capable of producing marginally severe hail and outflow gusts for a few hours later this afternoon/evening. ..Thompson/Squitieri.. 07/12/2022 Read more

MD 1454 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF NORTHERN NY/VT INTO PA AND FAR NORTHERN NJ
Mesoscale Discussion 1454 NWS Storm Prediction Center Norman OK 1040 AM CDT Tue Jul 12 2022 Areas affected...Portions of northern NY/VT into PA and far northern NJ Concerning...Severe potential...Watch possible Valid 121540Z - 121745Z Probability of Watch Issuance...60 percent SUMMARY...The overall severe threat should gradually increase into the afternoon, with both damaging winds and hail possible. One or more Severe Thunderstorm Watches will probably be needed. DISCUSSION...An upper trough evident on water vapor satellite imagery over the Great Lakes and Ontario/Quebec will continue eastward across the Northeast and Mid-Atlantic today. Rather strong mid-level flow of 45-55+ kt will accompany the upper trough, and aid in strong effective bulk shear and updraft organization. Partly to mostly sunny conditions are ongoing across much of NY/VT into PA. Continued diurnal heating will likely result in surface temperatures increasing into well into the 80s and lower 90s later this afternoon. MLCAPE around 1000-2000 J/kg should develop ahead of a poorly defined cold front. Weak convergence along/ahead of this boundary and ascent associated with the upper trough will aid robust thunderstorm development over the next couple of hours. Deep-layer shear of 45-50+ kt will support some potential for supercells with both a hail and damaging wind threat. Still, most guidance suggests that a line of convection should eventually consolidate with eastward extent into eastern NY/PA later this afternoon. If this evolution occurs, then damaging winds should become the primary severe hazard. One or more Severe Thunderstorm Watches will probably be needed from parts of northern NY/VT into PA and vicinity to address this gradually increasing severe threat. ..Gleason/Thompson.. 07/12/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BTV...OKX...ALY...PHI...BGM...CTP...PBZ... LAT...LON 40137994 43567509 45067340 45057209 44487223 43447286 41307439 40367559 39947635 39757779 39737942 40137994 Read more