Severe Storms

No watches are valid as of Fri Jun 24 16:37:01 UTC 2022.

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1053 AM CDT Fri Jun 24 2022 Valid 241630Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF NORTH DAKOTA...SOUTH DAKOTA...AND NORTHERN MINNESOTA... ...SUMMARY... Severe thunderstorms with the potential for widespread damaging wind gusts, very large hail, and a couple of tornadoes are expected from the eastern Dakotas into northwestern Minnesota this afternoon into tonight. ...ND/SD/MN... Morning water vapor imagery shows a broad upper trough across the northern Rockies today, with an embedded shortwave trough currently along the MT/WY border. This feature will track into the northern Plains later today, with large scale forcing for ascent overspreading parts of the Dakotas. Strong heating across eastern/central ND and convergence along a surface boundary will lead to afternoon thunderstorm development from south-central into northeast ND. Other storms will form by late afternoon to the north of the boundary across western/central ND as the upper trough approaches. Forecast soundings suggest strong instability (MLCAPE of 2500-4500 J/kg) and favorable effective shear for supercell storm structures capable of very large hail and perhaps a tornado or two. Storms are expected to develop southward along boundary into central SD during the evening, with gradual upscale growth into bowing line segments. This activity will spread into western MN with the risk of rather widespread damaging winds. ...Northeast WY/northwest SD... A consensus of 12z model guidance shows a cluster of afternoon thunderstorms forming over northeast WY and the Black Hills region. Moisture is more limited in this area, yielding MLCAPE values only into the 1000 J/kg range. However, steep lapse rates, cool temperatures aloft (-12C at 500mb), and 30-40 knots of westerly flow mid-level flow may result in a few supercells capable of hail and damaging wind gusts. ...Southeast NE and vicinity... Morning convection has resulted in an outflow boundary extending from western MO into eastern KS. This boundary is forecast to drift northward toward the KS/NE border by late afternoon, with forecast soundings showing relatively large hodographs and strong instability - posing a conditional risk of severe storms. However, no 12z CAM guidance shows any thunderstorms forming in this area due to a relatively warm capping layer. Have therefore removed the SLGT, but continue to acknowledge the conditional risk of significant severe weather if a storm can initiate/persist. ...GA/FL... Numerous afternoon thunderstorms are expected from the FL peninsula into central GA. A hot, humid, and very unstable air mass is present in this corridor with dewpoints in the mid/upper 70s and MLCAPE over 3000 J/kg. Shear is weak, but multicell storms capable of locally strong/damaging wet microbursts appear possible. ..Hart/Jirak.. 06/24/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1053 AM CDT Fri Jun 24 2022 Valid 241630Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF NORTH DAKOTA...SOUTH DAKOTA...AND NORTHERN MINNESOTA... ...SUMMARY... Severe thunderstorms with the potential for widespread damaging wind gusts, very large hail, and a couple of tornadoes are expected from the eastern Dakotas into northwestern Minnesota this afternoon into tonight. ...ND/SD/MN... Morning water vapor imagery shows a broad upper trough across the northern Rockies today, with an embedded shortwave trough currently along the MT/WY border. This feature will track into the northern Plains later today, with large scale forcing for ascent overspreading parts of the Dakotas. Strong heating across eastern/central ND and convergence along a surface boundary will lead to afternoon thunderstorm development from south-central into northeast ND. Other storms will form by late afternoon to the north of the boundary across western/central ND as the upper trough approaches. Forecast soundings suggest strong instability (MLCAPE of 2500-4500 J/kg) and favorable effective shear for supercell storm structures capable of very large hail and perhaps a tornado or two. Storms are expected to develop southward along boundary into central SD during the evening, with gradual upscale growth into bowing line segments. This activity will spread into western MN with the risk of rather widespread damaging winds. ...Northeast WY/northwest SD... A consensus of 12z model guidance shows a cluster of afternoon thunderstorms forming over northeast WY and the Black Hills region. Moisture is more limited in this area, yielding MLCAPE values only into the 1000 J/kg range. However, steep lapse rates, cool temperatures aloft (-12C at 500mb), and 30-40 knots of westerly flow mid-level flow may result in a few supercells capable of hail and damaging wind gusts. ...Southeast NE and vicinity... Morning convection has resulted in an outflow boundary extending from western MO into eastern KS. This boundary is forecast to drift northward toward the KS/NE border by late afternoon, with forecast soundings showing relatively large hodographs and strong instability - posing a conditional risk of severe storms. However, no 12z CAM guidance shows any thunderstorms forming in this area due to a relatively warm capping layer. Have therefore removed the SLGT, but continue to acknowledge the conditional risk of significant severe weather if a storm can initiate/persist. ...GA/FL... Numerous afternoon thunderstorms are expected from the FL peninsula into central GA. A hot, humid, and very unstable air mass is present in this corridor with dewpoints in the mid/upper 70s and MLCAPE over 3000 J/kg. Shear is weak, but multicell storms capable of locally strong/damaging wet microbursts appear possible. ..Hart/Jirak.. 06/24/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Fri Jun 24 2022 Valid 241300Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FOR PARTS OF THE EASTERN DAKOTAS INTO NORTHWESTERN MN... ...SUMMARY... Severe thunderstorms with gusts up to 75 mph, very large hail up to 3 inches in diameter, and a couple of tornadoes are expected from the eastern Dakotas into northwestern Minnesota this afternoon into tonight. ...Northern Plains and vicinity this afternoon into tonight... A corridor of low 70s dewpoints persists this morning from southeast ND into central SD, to the east of a stalled front. Cyclogenesis is expected today along the stalled front, as an upstream shortwave trough moves eastward over MT, and a separate shortwave trough ejects northeastward from UT/WY. The front will begin to move eastward later this evening into tonight in response to the approaching midlevel troughs, with scattered-numerous thunderstorms expected along and ahead of the front across the central/eastern Dakotas into northwest MN. Surface heating within the moist, pre-frontal air mass, beneath very steep midlevel lapse rates near 9 C/km, will result in MLCAPE of 3500-4500 J/kg. Convective inhibition will likewise weaken by mid afternoon, when thunderstorm development becomes likely. The stronger mid-upper flow will tend to lag west of the cold front, but should be sufficient for supercells close to the boundary. The large CAPE/steep lapse rate environment will support isolated very large hail up to 3 inches in diameter and a couple of tornadoes with the supercells, but there will likely be a tendency for fairly quick upscale growth into clusters/line segments. Large CAPE will favor precipitation loaded downdrafts and large DCAPE will favor intense downdrafts, with the potential for swaths of damaging winds with occasional significant (75 mph) severe outflow gusts late this afternoon into early tonight as storms spread eastward from the Dakotas into MN. Other clusters of more high-based storms are expected to form farther southwest across the central Rockies, and some of this convection will move into the High Plains this evening in association with the ejecting UT/WY shortwave trough. These storms could be maintained long enough to reach the richer moisture/larger CAPE in the vicinity of the stalled front, where large hail will become more of a threat. ...Western GA into FL this afternoon... A surface trough from western GA into north FL, along with daytime heating and local sea breeze circulations, will help focus thunderstorm development by early-mid afternoon. Strong surface heating/mixing with hot afternoon temperatures, as well boundary-layer dewpoints of 70-76 F, will support MLCAPE near 3000 J/kg this afternoon along the surface trough. The strong surface heating will also drive steep low-level lapse rates, and DCAPE at or above 1000 J/kg will favor occasional damaging gusts with downbursts in south-southwest moving clusters of storms this afternoon/evening. ..Thompson/Jewell.. 06/24/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Fri Jun 24 2022 Valid 241300Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FOR PARTS OF THE EASTERN DAKOTAS INTO NORTHWESTERN MN... ...SUMMARY... Severe thunderstorms with gusts up to 75 mph, very large hail up to 3 inches in diameter, and a couple of tornadoes are expected from the eastern Dakotas into northwestern Minnesota this afternoon into tonight. ...Northern Plains and vicinity this afternoon into tonight... A corridor of low 70s dewpoints persists this morning from southeast ND into central SD, to the east of a stalled front. Cyclogenesis is expected today along the stalled front, as an upstream shortwave trough moves eastward over MT, and a separate shortwave trough ejects northeastward from UT/WY. The front will begin to move eastward later this evening into tonight in response to the approaching midlevel troughs, with scattered-numerous thunderstorms expected along and ahead of the front across the central/eastern Dakotas into northwest MN. Surface heating within the moist, pre-frontal air mass, beneath very steep midlevel lapse rates near 9 C/km, will result in MLCAPE of 3500-4500 J/kg. Convective inhibition will likewise weaken by mid afternoon, when thunderstorm development becomes likely. The stronger mid-upper flow will tend to lag west of the cold front, but should be sufficient for supercells close to the boundary. The large CAPE/steep lapse rate environment will support isolated very large hail up to 3 inches in diameter and a couple of tornadoes with the supercells, but there will likely be a tendency for fairly quick upscale growth into clusters/line segments. Large CAPE will favor precipitation loaded downdrafts and large DCAPE will favor intense downdrafts, with the potential for swaths of damaging winds with occasional significant (75 mph) severe outflow gusts late this afternoon into early tonight as storms spread eastward from the Dakotas into MN. Other clusters of more high-based storms are expected to form farther southwest across the central Rockies, and some of this convection will move into the High Plains this evening in association with the ejecting UT/WY shortwave trough. These storms could be maintained long enough to reach the richer moisture/larger CAPE in the vicinity of the stalled front, where large hail will become more of a threat. ...Western GA into FL this afternoon... A surface trough from western GA into north FL, along with daytime heating and local sea breeze circulations, will help focus thunderstorm development by early-mid afternoon. Strong surface heating/mixing with hot afternoon temperatures, as well boundary-layer dewpoints of 70-76 F, will support MLCAPE near 3000 J/kg this afternoon along the surface trough. The strong surface heating will also drive steep low-level lapse rates, and DCAPE at or above 1000 J/kg will favor occasional damaging gusts with downbursts in south-southwest moving clusters of storms this afternoon/evening. ..Thompson/Jewell.. 06/24/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Thu Jun 23 2022 Valid 231630Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF KS/NE/SD/MN... ...SUMMARY... Scattered severe thunderstorms are most likely over parts of the central Great Plains and the central portions of Minnesota to South Dakota, mainly this evening. ...Northern KS/southern NE... Low-level warm theta-e advection has maintained a swath of elevated convection centered on northeast to east-central KS, just northeast of the surface warm front. To the south and west of this activity, robust boundary-layer heating is underway, likely increasing baroclinicity across the front by late afternoon. A low-amplitude mid-level perturbation over the southern Rockies should be favorably timed to aid in scattered high-based convection developing along the lee trough in western KS to its intersection with the warm front near southwest NE. While morning guidance varies substantially with the overall thermodynamic environment, the 12Z HRW-NSSL/ARW and NAM-Nest all suggest potential for at least a couple long-lived supercells slowly spreading east-southeast from southwest NE across northern KS. Midlevel flow will not be strong, although speed shear into the upper levels will favor large hail growth. Hodographs will depend on the degree of low-level easterly flow component in the warm advection zone along and north of the warm front, which guidance also varies substantially on. Even so, an increase in a nocturnal southerly low-level jet will likely assist in potential for a small MCS this evening. Given the conditionally favorable setup, potential for sig hail and wind is apparent in addition to a tornadic supercell or two. ...Central portions of MN/SD... A weak surface trough, associated with a low-amplitude shortwave impulse over northern ON, will drift southeast across northeast to west-central MN, with a separate surface trough extending north from western KS/NE into central SD. An increase in low-level moisture from the south and southwest, combined with strong daytime heating and modest convergence along the troughs, should support isolated to scattered thunderstorm development during the late afternoon to early evening. While model moisture forecasts are likely overdone, and weak large-scale forcing for ascent limits confidence, steep mid-level lapse rates and adequate deep-layer shear will support conditional potential for a few supercells and multicell clustering. Most morning CAM guidance suggests a narrow corridor of cat 2/SLGT-risk caliber storms should form with a threat for large hail and damaging winds. ...Central/eastern MT... A mid-level closed low over southern BC will move eastward, with the primary jet crossing northern MT through tonight. Associated surface cold front will push east and provide a focus for isolated to scattered thunderstorm development across central to eastern MT during the late afternoon and evening. Low-level moisture will remain limited with boundary-layer dew points in the 40s, yielding MLCAPE to only around 500 J/kg. Still, inverted-v thermodynamic profiles and some increase in mid-level flow will support the threat for isolated severe gusts and small to marginally severe hail. ...Eastern NV/western UT... A low-amplitude shortwave trough over the Sierra NV will gradually progress east across parts of NV into western UT through tonight. Moderate forcing for ascent ahead of this trough, combined with daytime heating/mixing, will support scattered high-based thunderstorm development. Limited boundary-layer moisture will result in only meager MLCAPE and effective bulk shear will remain weak. But deeply mixed inverted-v thermodynamic profiles and DCAPE greater than 1000 J/kg will support a threat for isolated severe gusts. ..Grams/Weinman.. 06/23/2022 Read more

No watches are valid as of Thu Jun 23 16:35:01 UTC 2022.

No Mesoscale Discussions are in effect as of Thu Jun 23 16:35:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 AM CDT Thu Jun 23 2022 Valid 231300Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT NEAR THE KS/NE BORDER... ...SUMMARY... Widely scattered severe thunderstorms are possible across portions of the central Great Plains this afternoon and evening. Large hail and severe gusts will be the primary threats with the stronger storms. ...Northern KS/southern NE this afternoon through tonight... Weak perturbations emanating from the monsoonal moisture plume will drift eastward across the central Plains, around the northern periphery of the southern Plains closed high aloft. At the surface, a warm front will move slowly northward across KS, to the east of a lee cyclone near the CO/KS border by this evening. A corridor of 68-70 F boundary-layer dewpoints will be maintained in the vicinity of the warm front across KS/NE, with strong surface heating and deep mixing expected to the southwest of the warm front across western KS. The net result should be relatively weak convective inhibition and the potential for surface-based thunderstorm development late this afternoon/evening along the warm front close to the KS/NE border, with the potential for elevated storm development persisting overnight on the nose of a 30+ kt low-level jet. There is some uncertainty regarding the role/persistence of morning clouds/convection in late afternoon storm development, though there should be at least some clearing along the northwest KS/southwest NE border, where storm development is more probable by 22-00z. Midlevel flow will not be strong (though 50 kt flow is expected above the 300 mb level), so low-midlevel hodograph length will depend on the degree of low-level easterly low-level flow component in the warm advection zone along and north of the warm front. A few supercells will be possible with large hail and damaging gusts, and the tornado threat will depend on getting storms into the areas of backed low-level flow and richer low-level moisture. Otherwise, storms may coalesce into clusters overnight, with a continuing threat for isolated hail/wind. ...Northeast SD into MN this evening into tonight... A weak surface trough, associated with a shortwave trough over western ON, will move southeastward into northeast SD and central/northern MN by late afternoon. An increase in low-level moisture from the south during the day, combined with daytime heating and convergence along the trough, could support widely scattered thunderstorm development by late afternoon/evening along the surface trough. The specific degree of low-level moistening and resultant increases in CAPE are a bit uncertain (some model guidance appears to be a bit high with the 68+ dewpoints by evening), and storm coverage is in question given the moisture and weak forcing for ascent. Wind profiles appear to be on the lower margins for organized/supercell storms. Given these factors, will maintain Marginal risk for the conditional threat. ...Central MT this afternoon/evening... A midlevel level closed low over southern BC will move eastward, with the primary midlevel jet crossing northern MT through tonight. The midlevel low will be accompanied by a surface cold front, which will provide a focus for thunderstorm development across central MT this afternoon/evening. Low-level moisture will remain limited across MT (boundary-layer dewpoints in the low-mid 40s with daytime heating/mixing), which will likewise limit buoyancy. Still, inverted-v profiles and some increase in midlevel flow will support the threat for isolated strong-severe outflow gusts from late afternoon into this evening. ...Eastern NV/western UT this afternoon/evening... A weak closed low over central CA will evolve into an open wave and eject east-northeastward over NV/UT through tonight. Weak ascent downstream from the midlevel trough, combined with daytime heating/mixing, will result in weak buoyancy and inverted-v profiles favorable for high-based thunderstorm development. A modest increase in midlevel flow and the steep low-level lapse rates/DCAPE greater than 1000 J/kg will support the threat for isolated severe outflow gusts. ..Thompson/Jewell.. 06/23/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 AM CDT Thu Jun 23 2022 Valid 231300Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT NEAR THE KS/NE BORDER... ...SUMMARY... Widely scattered severe thunderstorms are possible across portions of the central Great Plains this afternoon and evening. Large hail and severe gusts will be the primary threats with the stronger storms. ...Northern KS/southern NE this afternoon through tonight... Weak perturbations emanating from the monsoonal moisture plume will drift eastward across the central Plains, around the northern periphery of the southern Plains closed high aloft. At the surface, a warm front will move slowly northward across KS, to the east of a lee cyclone near the CO/KS border by this evening. A corridor of 68-70 F boundary-layer dewpoints will be maintained in the vicinity of the warm front across KS/NE, with strong surface heating and deep mixing expected to the southwest of the warm front across western KS. The net result should be relatively weak convective inhibition and the potential for surface-based thunderstorm development late this afternoon/evening along the warm front close to the KS/NE border, with the potential for elevated storm development persisting overnight on the nose of a 30+ kt low-level jet. There is some uncertainty regarding the role/persistence of morning clouds/convection in late afternoon storm development, though there should be at least some clearing along the northwest KS/southwest NE border, where storm development is more probable by 22-00z. Midlevel flow will not be strong (though 50 kt flow is expected above the 300 mb level), so low-midlevel hodograph length will depend on the degree of low-level easterly low-level flow component in the warm advection zone along and north of the warm front. A few supercells will be possible with large hail and damaging gusts, and the tornado threat will depend on getting storms into the areas of backed low-level flow and richer low-level moisture. Otherwise, storms may coalesce into clusters overnight, with a continuing threat for isolated hail/wind. ...Northeast SD into MN this evening into tonight... A weak surface trough, associated with a shortwave trough over western ON, will move southeastward into northeast SD and central/northern MN by late afternoon. An increase in low-level moisture from the south during the day, combined with daytime heating and convergence along the trough, could support widely scattered thunderstorm development by late afternoon/evening along the surface trough. The specific degree of low-level moistening and resultant increases in CAPE are a bit uncertain (some model guidance appears to be a bit high with the 68+ dewpoints by evening), and storm coverage is in question given the moisture and weak forcing for ascent. Wind profiles appear to be on the lower margins for organized/supercell storms. Given these factors, will maintain Marginal risk for the conditional threat. ...Central MT this afternoon/evening... A midlevel level closed low over southern BC will move eastward, with the primary midlevel jet crossing northern MT through tonight. The midlevel low will be accompanied by a surface cold front, which will provide a focus for thunderstorm development across central MT this afternoon/evening. Low-level moisture will remain limited across MT (boundary-layer dewpoints in the low-mid 40s with daytime heating/mixing), which will likewise limit buoyancy. Still, inverted-v profiles and some increase in midlevel flow will support the threat for isolated strong-severe outflow gusts from late afternoon into this evening. ...Eastern NV/western UT this afternoon/evening... A weak closed low over central CA will evolve into an open wave and eject east-northeastward over NV/UT through tonight. Weak ascent downstream from the midlevel trough, combined with daytime heating/mixing, will result in weak buoyancy and inverted-v profiles favorable for high-based thunderstorm development. A modest increase in midlevel flow and the steep low-level lapse rates/DCAPE greater than 1000 J/kg will support the threat for isolated severe outflow gusts. ..Thompson/Jewell.. 06/23/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1057 AM CDT Wed Jun 22 2022 Valid 221700Z - 231200Z The forecast remains on track with only minor adjustments needed based on trends in latest hi-res convective models. Showers and thunderstorms are ongoing across southern CA. MRMS rainfall estimates show that much of this activity is producing wetting rainfall, though a few cells are producing little precipitation. This mixture of wet and dry storms is expected to continue through the day and into the evening hours. Despite the areas of wetting rainfall, regional GACCs have reported a few new fire starts from recent lightning given the dry fuel status. Strong downburst winds are possible given the dry low-level air sampled in morning soundings (see the Day 1 Convective Outlook for additional details on the severe wind potential). Across UT, observed trends continue to point towards thunderstorm development by mid/late afternoon across the Greater Four Corners region. The dry thunderstorm risk area is expanded to accommodate locations where the potential for thunderstorms has increased and ERC values are above seasonal average. ..Moore.. 06/22/2022 .PREV DISCUSSION... /ISSUED 0122 AM CDT Wed Jun 22 2022/ ...Synopsis... Upper-level ridging centered within the Plains will retrograde westward during the day today. A weak cut-off low, currently off the southern California coast on water vapor imagery, will remain quasi-stationary before being pushed northeastward by the retrograding ridge late in the period. Fire weather concerns will be focused within southern California and within a small portion of the southern Great Basin. Both areas will see potential for a few dry thunderstorms as moisture continues to work its way westward around the ridge. Parts of southern Utah into far northwest Arizona will likely have lower PWAT values and see more traditional dry thunderstorms. Within southern California, current GPS PWAT retrievals show values over 1 inch nudging into the southern border. Forecast soundings tomorrow indicate that PWAT values will likely be near or exceed 1 inch over much of the area. Furthermore, storm coverage could approach scattered categorical designation given the influence of the cut-off low. Low-levels will be quite dry. Dewpoint depressions of 40-50 F are depicted in forecast soundings tomorrow afternoon. Even with fairly high PWAT values, a mix of wet and isolated dry storms is likely given the low-level moisture profile. Area fuels are generally at or slightly below seasonal dryness and will support ignition. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Wed Jun 22 16:00:02 UTC 2022.

No Mesoscale Discussions are in effect as of Wed Jun 22 16:00:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Wed Jun 22 2022 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF THE CENTRAL APPALACHIANS/MID-ATLANTIC TO THE UPPER OH VALLEY... ...SUMMARY... Damaging winds and isolated large hail will be possible this afternoon/evening from central Pennsylvania into Virginia, and westward into the upper Ohio Valley. Isolated downbursts and marginally severe hail may occur along the Kansas/Oklahoma border this evening, and isolated damaging downbursts will be possible through this evening across parts of southern/central California. ...Upper OH Valley and Mid-Atlantic this afternoon/evening... A closed low off the southeast New England coast will drift westward, while a separate shortwave trough in the westerlies moves from the upper Great Lakes toward the lower Great Lakes. The Great Lakes shortwave trough will be accompanied by a surface cold front that will move southeastward into the upper OH Valley later this afternoon/evening. Farther east, a north-south front will extend from eastern VA into central PA, with strong surface heating expected west of this north-south front and in advance of the upper OH Valley cold front. There will also be some increase in low-level moisture during the day across the OH Valley into western/central PA, as well as along the stalled front into VA. The net result will be a corridor of moderate-strong buoyancy (MLCAPE from 1500 J/kg along the Mid-Atlantic stalled front to nearly 3000 J/kg along the OH Valley cold front. Northwesterly to northerly midlevel flow on the west side of the closed low will favor southward-moving clusters by early afternoon from central PA into VA, along and west of the stalled north-south front (with a cooler marine layer to the east of the front). Slightly longer hodographs and a little larger low-level hodograph curvature (associated with weak warm advection) will be present along the north-south front, where there will be some potential for embedded/transient supercell structures. However, multicell clusters should be the dominant storm mode, with a primary threat for damaging outflow gusts as clusters spread southward into an environment with weaker buoyancy and steeper low-level lapse rates with southward extent. Multicell storm clusters are also expected along the cold front into the upper OH Valley by mid-late afternoon. Vertical shear will be weak over the upper OH Valley, but large CAPE/DCAPE will favor damaging outflow gusts with multicell clusters through the afternoon into late evening. ...Southern/central CA through this evening... A plume of low-midlevel moisture and weak ascent will continue to spread north-northwestward from southern CA into the San Joaquin Valley, around the eastern periphery of a midlevel low just off the central CA coast. Some convection is ongoing in the moisture plume, and pockets of surface heating/mixing in cloud breaks will contribute to deep inverted-v profiles. Buoyancy (MLCAPE near 500 J/kg) will be sufficient for substantial updrafts and precipitation loading to realize the downburst potential in the environment of steep low-level lapse rates and DCAPE greater than 1000 J/kg. Thus, isolated damaging gusts will be possible, mainly later today into this evening from the higher terrain in southern CA northward into the San Joaquin Valley. ...KS/OK border late this afternoon/evening... A surface cold front in KS, reinforced by outflow with convection overnight, will tend to stall near the OK/KS border by this afternoon. This area will be along the northwest periphery of the midlevel high over the southern Plains, and on the southern periphery of the monsoonal moisture plume emanating from NM. Though forcing for ascent will be weak, strong surface heating and deep mixing impinging on the front could support thunderstorm development late this afternoon into this evening. Despite some weak enhancement to the hodographs on the cool side of the boundary, vertical shear will largely remain weak, with multicell clusters the expected convective mode. MLCAPE near 2000 J/kg and DCAPE in excess of 1000 J/kg will support isolated strong/damaging outflow gusts, and perhaps marginally severe hail for a few hours this evening. ..Thompson/Jewell.. 06/22/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1101 AM CDT Tue Jun 21 2022 Valid 211700Z - 221200Z An isolated dry thunderstorm risk area is introduced for portions of southern California. 12 UTC soundings from the region sampled very dry air within the lowest 3 km. This dry air is expected to remain in place over the next 24 hours as mid-level moisture improves via a monsoonal moisture surge from the south. Thunderstorm chances will increase late tonight (likely after 09 UTC) and spread from south to north towards central CA as the upper disturbance off the coast moves onshore. Morning ensemble guidance has a light QPF signal across this region during the 09-12 UTC time frame, and corresponding forecast soundings show adequate instability (250-500 J/kg MUCAPE) atop the dry low-level air mass. While PWAT values will be somewhat elevated, the potential for dry lightning strikes appears sufficiently high to introduce a risk area. Wind-driven fire weather concerns remain low. Localized elevated (to perhaps briefly critical) fire weather conditions are possible within the San Gabriel to San Bernardino mountains in southern CA, as well as across parts of northwest AZ. However, this activity will most likely remain fairly limited spatially and temporally. ..Moore.. 06/21/2022 .PREV DISCUSSION... /ISSUED 0114 AM CDT Tue Jun 21 2022/ ...Synopsis... Upper-level ridging will be present across a wide swath of the lower 48 today. A cutoff low off the California coast will aid in mid-level moisture return late in forecast period. The overall fire weather risk is expected to remain low as weak surface winds are expected across the areas with the driest fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Jun 21 16:04:01 UTC 2022.

No Mesoscale Discussions are in effect as of Tue Jun 21 16:04:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0721 AM CDT Tue Jun 21 2022 Valid 211300Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON/EVENING FROM THE UPPER GREAT LAKES TO THE CENTRAL PLAINS... ...SUMMARY... Isolated damaging winds and marginally severe hail will be possible from the upper Great Lakes to the central Plains late this afternoon/evening. ...Upper Great Lakes to the central Plains this evening... No changes to the previous outlook. A midlevel shortwave trough over the northern Plains will move generally eastward toward the upper Great Lakes, around the northern periphery of a closed midlevel high over the mid MS Valley. There will be some suppression of midlevel heights across the Great Lakes, but the majority of the height falls and stronger midlevel flow will be displaced to the cool side of an associated surface cold front that will move southeastward across the upper Midwest/Great Lakes. This will leave weak forcing for ascent and weak vertical shear in the warm sector this afternoon. A corridor of boundary-layer dewpoints in the lower 70s will be maintained immediately ahead of the cold front, where strong buoyancy (MLCAPE of 2000-3500 J/kg) is expected with daytime heating beneath a residual plume of 7.5 C/km midlevel lapse rates. Since forcing for ascent will be relatively shallow/weak along the cold front, convective initiation will rely on strong surface heating/mixing to eliminate convective inhibition, which is somewhat more probable from KS into northern MO. A few multicell clusters are expected along the front, with the strong buoyancy supporting a marginal hail threat, and steep low-level lapse rates/DCAPE of 1000-1500 J/kg favoring isolated severe outflow gusts for a few hours this evening. ..Thompson/Jewell.. 06/21/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0721 AM CDT Tue Jun 21 2022 Valid 211300Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON/EVENING FROM THE UPPER GREAT LAKES TO THE CENTRAL PLAINS... ...SUMMARY... Isolated damaging winds and marginally severe hail will be possible from the upper Great Lakes to the central Plains late this afternoon/evening. ...Upper Great Lakes to the central Plains this evening... No changes to the previous outlook. A midlevel shortwave trough over the northern Plains will move generally eastward toward the upper Great Lakes, around the northern periphery of a closed midlevel high over the mid MS Valley. There will be some suppression of midlevel heights across the Great Lakes, but the majority of the height falls and stronger midlevel flow will be displaced to the cool side of an associated surface cold front that will move southeastward across the upper Midwest/Great Lakes. This will leave weak forcing for ascent and weak vertical shear in the warm sector this afternoon. A corridor of boundary-layer dewpoints in the lower 70s will be maintained immediately ahead of the cold front, where strong buoyancy (MLCAPE of 2000-3500 J/kg) is expected with daytime heating beneath a residual plume of 7.5 C/km midlevel lapse rates. Since forcing for ascent will be relatively shallow/weak along the cold front, convective initiation will rely on strong surface heating/mixing to eliminate convective inhibition, which is somewhat more probable from KS into northern MO. A few multicell clusters are expected along the front, with the strong buoyancy supporting a marginal hail threat, and steep low-level lapse rates/DCAPE of 1000-1500 J/kg favoring isolated severe outflow gusts for a few hours this evening. ..Thompson/Jewell.. 06/21/2022 Read more

No watches are valid as of Mon Jun 20 13:43:02 UTC 2022.