Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Fri Mar 31 2023 Valid 312000Z - 011200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS FOR FAR SOUTHEAST IOWA...WEST-CENTRAL ILLINOIS...FAR NORTHEAST MISSOURI AND IN PART OF EASTERN ARKANSAS...NORTHERN MISSISSIPPI...AND SOUTHWESTERN TENNESSEE...... ...SUMMARY... A severe weather outbreak will continue this afternoon and evening across a large portion of the Mississippi Valley. Multiple strong tornadoes are expected, some long tracked. A violent tornado will be possible within the High Risk areas. Swaths of intense damaging wind gusts along with very large hail are expected as well. ...20Z Update... An outbreak of severe weather continues to evolve this afternoon, with numerous storms currently from IA near the surface low southward along a dryline into northeast TX. The air mass will continue to destabilize over this expansive area, with large-scale lift increase as well. Shear will remain extremely favorable for supercell tornadoes within multiple regimes from the surface low/vort max across IA/MO/IL to the trailing dryline over the lower MS Valley where dewpoints and MLCAPE are greater. 0-1 km shear is particularly strong currently from central AR into southeast MO, with increasing values expected through evening to the northeast. As a strong vort max with rapid cooling aloft overspread the IA and northern MO/IL region, existing storms are expected to intensify, with several likely becoming tornadic and producing very large hail. The very steep lapse rates in this region will maximize updrafts, and may support several intense tornadoes. Rising dewpoints would further support the tornado risk later today. For more information, see any of multiple mesoscale discussions that remain in effect, including #397 for NE MO/Central IL, #398 for northern MO, #399 for central AR and #400 for northern IL into far southern WI. ..Jewell.. 03/31/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Mar 31 2023/ ...Synopsis... A dangerous severe weather outbreak is likely across a large portion of the central states this afternoon into tonight. Long-track, strong to potentially violent tornadoes are forecast across a broad region of the MS Valley. The propensity of model-supporting evidence and observational trends lends confidence in the upgrade to bimodal High Risks for the mid MS Valley and lower MS Valleys. ...Midwest and the Mid-MS to OH Valleys... Morning water-vapor imagery shows a potent 500-mb speed max ejecting east-northeast across the TX Panhandle/western OK to the south of a mid-level low over northern NE. A 992-mb cyclone over western IA will deepen through this afternoon as it matures into the Upper MS Valley before occluding this evening. Visible-satellite imagery/surface observations show a plume of increasingly rich low-level moisture rapidly advecting northward into the lower MO Valley with surface dewpoints rising into the lower 60s F. Strong heating in combination with low-level moistening and cooling mid-level temperatures, are expected to result in a relatively large corridor featuring 1000-3000 J/kg MLCAPE across a moderate to strongly unstable warm sector. In agreement with prior forecast thinking, it seems the primary severe evolution remains likely to evolve beginning around 19Z to the southeast of the deep cyclone across central IA and broadening in coverage through the late afternoon along the north/south-oriented cold front arcing southward into eastern MO. Very steep mid-level lapse rates and an elongated mid to upper-level hodograph will initially support a broken band of supercells capable of producing very large hail. The risk for tornadoes will likely focus initially with supercells near and southeast of the surface low. As this activity rapidly spreads into an increasingly favorable low-level SRH environment in the eastern half of IA and the MS Valley, several to numerous tornadoes are expected to form. Forecast soundings within the High Risk show large 0-3-km MLCAPE co-located with intense speed shear and large low-level and elongated hodographs. Within this arcing band of quasi-discrete supercells, several long-track strong to potentially violent tornadoes are forecast for this afternoon into the evening. Eventual upscale growth into an intense squall line with embedded cellular elements is expected to evolve during the evening into tonight across IL and rapidly sweep eastward across the OH Valley/southern Great Lakes. Some risk for tornadoes will probably spread east with the squall line coincident with a 70-kt 700-mb speed max overspreading the region. Severe gusts (60-90 mph) are possible with surges/bowing structures and embedded cells within the band of storms. Have expanded the Moderate Risk due to significant wind gusts across eastern IL into IN. By late tonight, the evolving QLCS will outpace weakening surface-based instability around the central OH Valley. Extreme low-level wind fields could support a waning wind/brief tornado threat approaching the central Appalachians. ...Ark-La-Tex to the Lower MS/TN Valleys... Multiple rounds of severe convection are expected to unfold, intensifying this afternoon in AR and Ark-La-Tex, before continuing east across the Lower MS into the TN Valleys through tonight. Rapid airmass modification is currently underway across the lower MS Valley with mid 60s deg F dewpoints surging north-northeast across southern AR and towards the AR/TN/MS region. Initially, a capped warm sector via an EML will act to limit storm development (isolated early afternoon storms with mainly a hail risk). However, as buoyancy increases (1500-2500 J/kg MLCAPE) and shear profiles intensify, very favorable hodographs are forecast to develop by mid-late afternoon across southern/eastern AR into adjacent portions of MS/TN (effective SRH 300-600 m2/s2). Scattered thunderstorms will likely develop by late afternoon with these rapidly evolving into supercells. Strong to potentially violent tornadoes are forecast with a few long-tracked supercells. Upscale growth into a QLCS with embedded supercells appears probable during the late evening and overnight as frontal convergence strengthens. Tornadoes and significant damaging wind swaths will remain possible well into the night across at least into the TN Valley, until warm-sector low-level flow becomes more veered towards the end of the period. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1244 PM CDT Fri Mar 31 2023 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE NORTHEAST...AND OVER PARTS OF THE SOUTHEAST.... ...SUMMARY... Damaging winds are expected across parts of the Northeast Saturday during the day and through early evening. Other severe storms will be possible over parts of the Southeast. ...Synopsis... A large shortwave-trough will move across the Upper Great Lakes and OH Valley to the Mid Atlantic by 00Z, with substantial height falls/cooling aloft overspread the entire region. An intense leading midlevel jet streak will approach the Appalachians by midday, with a secondary cold pocket and vort max aloft affecting the I-95 corridor late in the day. To the south, moderate westerlies aloft will exist over the Southeast, as the influence of the upper trough grazes the area. At the surface, low pressure should gradually deepen as it moves east/northeast from southwest Ontario toward northern ME. Extending east of the low track will be a developing warm front which will bring 50s F dewpoints into southern VT/NH and perhaps ME. Although the primary surface low will move toward more stable areas to the north, a prominent surface trough will develop southward coincident with the secondary vort max moving rapidly east. While various regimes of severe weather may occur with these features, this secondary wave will affect the Mid Atlantic late in the day and into early evening, and is expected to result in wind damage from western MA and CT into far eastern PA, all of NJ, and parts of the Delmarva. A few tornadoes may occur over southern parts of this region. Farther south, a front/dryline will slow as it moves into southern AL and across GA during the day, with a more substantial cold front pushing east across VA and the Carolinas. Scattered severe storms are possible across these areas during the day. ...From eastern OH into New England... The initial severe risk on Saturday will likely be tied to the leading vort max associated with left-front quadrant of the midlevel jet. Cold temperatures aloft will result in 250-500 J/kg SBCAPE in the corridor from eastern OH/western PA across much of NY and into New England by late afternoon. The combination of very steep, deep-layer lapse rates along with increasing boundary-layer wind speeds suggest any convection at all will have the potential to enhance downward mixing. This seems likely given expected sufficient instability. The northward extent of this damaging wind regime will be limited by the warm front, and it is possible that this boundary eventually makes it into extreme southern ME. ...From the Delmarva across NJ and into southern New England... Southerly surface winds for most of the day will help deepen the moist boundary layer, with a plume of upper 50s F to near 60 F dewpoints from eastern VA northward across Philadelphia and into far southeast NY. Strong heating will occur along and west of this moist plume, priming the air mass for the arrival of an intense cold front arrive very late in the day and into early evening for eastern areas. Forecast soundings reveal supercell wind profiles with effective SRH over 300 m2/s2, and long hodographs as well. The forecast is for storms to form in the moist axis as the front rapidly intercepts the moist air mass, with rapid changes taking place aloft. Some of these storms could develop along coastal counties as well, and at least isolated supercells are expected. A conditional tornado risk will exist where SBCAPE remains favorable, centered over NJ and DE. Damaging winds will be quite likely with any strong convection given 50+ kt winds out of the northwest just off the surface. Clearly, these will be able to mix to the surface. Various models appear to be struggling with this area, thus there is uncertainty in the magnitude of the severe risk. ...Southern GA into the eastern Carolinas... Scattered showers and a few thunderstorms may be ongoing ahead of the surface boundary early in the day, beneath southwesterly 50 kt 850 mb flow and within a theta-e plume. Strong heating is expected near the synoptic boundary and deepening surface trough, and the presence of mid 60s F dewpoints will lead to ample instability to support daytime storms despite lack of upper support. With time, storms along the boundary may develop into supercells as deep-layer shear will be strong and effective SRH averages 150-200 m2/s2. Any supercell/tornado threat is expected to be limited as midlevel subsidence occurs, but sporadic hail, a brief tornado, and damaging gusts will all be possible through the afternoon. Rapid drying from the west should push the severe threat quickly eastward across the region and to the eastern Carolinas before 00Z. ..Jewell.. 03/31/2023 Read more

Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1139 AM CDT FRI MAR 31 2023 ...Outbreak of tornadoes and severe thunderstorms expected over parts of the portions of the Midwest and the lower MS/TN River Valleys this afternoon and tonight... * LOCATIONS... Illinois Iowa Arkansas Mississippi Tennessee Missouri Kentucky Alabama Indiana Wisconsin Louisiana Ohio * HAZARDS... Numerous tornadoes, several intense and long track Widespread damaging winds, some hurricane force Scattered large hail, some baseball size * SUMMARY... A severe weather outbreak appears increasingly likely, centered on this afternoon and evening, across a large portion of the Mississippi Valley. At least a few long-track, strong to potentially violent tornadoes are probable, particularly over portions of the Mid-Mississippi Valley to the Mid-South. Swaths of intense damaging wind gusts along with very large hail are expected as well. Preparedness actions... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Mar 31 2023 Valid 311630Z - 011200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS FOR FAR SOUTHEAST IOWA...WEST-CENTRAL ILLINOIS...FAR NORTHEAST MISSOURI AND IN PARTS OF EASTERN ARKANSAS...NORTHERN MISSISSIPPI...AND SOUTHWESTERN TENNESSEE... ...SUMMARY... A severe weather outbreak appears increasingly likely, centered on this afternoon and evening, across a large portion of the Mississippi Valley. At least a few long-track, strong to potentially violent tornadoes are probable, particularly over portions of the Mid-Mississippi Valley to the Mid-South. Swaths of intense damaging wind gusts along with very large hail are expected as well. ...Synopsis... A dangerous severe weather outbreak is likely across a large portion of the central states this afternoon into tonight. Long-track, strong to potentially violent tornadoes are forecast across a broad region of the MS Valley. The propensity of model-supporting evidence and observational trends lends confidence in the upgrade to bimodal High Risks for the mid MS Valley and lower MS Valleys. ...Midwest and the Mid-MS to OH Valleys... Morning water-vapor imagery shows a potent 500-mb speed max ejecting east-northeast across the TX Panhandle/western OK to the south of a mid-level low over northern NE. A 992-mb cyclone over western IA will deepen through this afternoon as it matures into the Upper MS Valley before occluding this evening. Visible-satellite imagery/surface observations show a plume of increasingly rich low-level moisture rapidly advecting northward into the lower MO Valley with surface dewpoints rising into the lower 60s F. Strong heating in combination with low-level moistening and cooling mid-level temperatures, are expected to result in a relatively large corridor featuring 1000-3000 J/kg MLCAPE across a moderate to strongly unstable warm sector. In agreement with prior forecast thinking, it seems the primary severe evolution remains likely to evolve beginning around 19Z to the southeast of the deep cyclone across central IA and broadening in coverage through the late afternoon along the north/south-oriented cold front arcing southward into eastern MO. Very steep mid-level lapse rates and an elongated mid to upper-level hodograph will initially support a broken band of supercells capable of producing very large hail. The risk for tornadoes will likely focus initially with supercells near and southeast of the surface low. As this activity rapidly spreads into an increasingly favorable low-level SRH environment in the eastern half of IA and the MS Valley, several to numerous tornadoes are expected to form. Forecast soundings within the High Risk show large 0-3-km MLCAPE co-located with intense speed shear and large low-level and elongated hodographs. Within this arcing band of quasi-discrete supercells, several long-track strong to potentially violent tornadoes are forecast for this afternoon into the evening. Eventual upscale growth into an intense squall line with embedded cellular elements is expected to evolve during the evening into tonight across IL and rapidly sweep eastward across the OH Valley/southern Great Lakes. Some risk for tornadoes will probably spread east with the squall line coincident with a 70-kt 700-mb speed max overspreading the region. Severe gusts (60-90 mph) are possible with surges/bowing structures and embedded cells within the band of storms. Have expanded the Moderate Risk due to significant wind gusts across eastern IL into IN. By late tonight, the evolving QLCS will outpace weakening surface-based instability around the central OH Valley. Extreme low-level wind fields could support a waning wind/brief tornado threat approaching the central Appalachians. ...Ark-La-Tex to the Lower MS/TN Valleys... Multiple rounds of severe convection are expected to unfold, intensifying this afternoon in AR and Ark-La-Tex, before continuing east across the Lower MS into the TN Valleys through tonight. Rapid airmass modification is currently underway across the lower MS Valley with mid 60s deg F dewpoints surging north-northeast across southern AR and towards the AR/TN/MS region. Initially, a capped warm sector via an EML will act to limit storm development (isolated early afternoon storms with mainly a hail risk). However, as buoyancy increases (1500-2500 J/kg MLCAPE) and shear profiles intensify, very favorable hodographs are forecast to develop by mid-late afternoon across southern/eastern AR into adjacent portions of MS/TN (effective SRH 300-600 m2/s2). Scattered thunderstorms will likely develop by late afternoon with these rapidly evolving into supercells. Strong to potentially violent tornadoes are forecast with a few long-tracked supercells. Upscale growth into a QLCS with embedded supercells appears probable during the late evening and overnight as frontal convergence strengthens. Tornadoes and significant damaging wind swaths will remain possible well into the night across at least into the TN Valley, until warm-sector low-level flow becomes more veered towards the end of the period. ..Smith/Lyons.. 03/31/2023 Read more

No watches are valid as of Thu Mar 30 21:29:01 UTC 2023.

MD 0385 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN OKLAHOMA TO WESTERN ARKANSAS AND FAR SOUTHWEST MISSOURI
Mesoscale Discussion 0385 NWS Storm Prediction Center Norman OK 0302 PM CDT Thu Mar 30 2023 Areas affected...Eastern Oklahoma to western Arkansas and far southwest Missouri Concerning...Severe potential...Watch unlikely Valid 302002Z - 302200Z Probability of Watch Issuance...5 percent SUMMARY...Elevated thunderstorms are expected to slowly increase in coverage and intensity through the remainder of the afternoon across eastern Oklahoma into adjacent portions of western Arkansas and southwest Missouri. While a few large hailstones are possible, this threat should remain too limited for watch issuance. DISCUSSION...Latest regional radar mosaics have shown a gradual increase in convective cells over northern TX into southern OK over the past hour. Lightning associated with this activity has steadily trended upward within the past 30 minutes as cloud top temperatures cool in IR imagery. This suggests that more robust convective initiation is likely underway and/or is imminent as lift continues within a zone of strong warm advection between 850-700 mb. 18 UTC soundings from OUN and FWD show around 500-1000 J/kg MUCAPE with effective bulk shear values around 30 knots. This environment is supportive of organized cells capable of severe hail, though recent reflectivity trends hint that thunderstorm clustering/storm interactions may modulate storm longevity and intensity to a degree - likely due to deep-layer shear vectors oriented along the zone of ascent. The expectation is for an increase in coverage of this activity as the zone of mid-level ascent shifts to the northeast into western AR and southwest MO this evening with a few strong to severe cells. Given the modest thermodynamic environment and limited potential for long-lived discrete convection, watch issuance is not anticipated. ..Moore/Hart.. 03/30/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SGF...SHV...TSA...ICT...FWD...OUN... LAT...LON 33589482 33519696 33599747 33789786 34149815 34629825 35109815 35409787 36989538 37199491 37229441 37149403 36809346 36399308 35649303 34979307 34679315 34229340 33979371 33829417 33589482 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Mar 30 2023 Valid 302000Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible this evening over parts of the central and southern Great Plains. No changes have been made to the outlook. See the previous discussion below for more information. ..Dean.. 03/30/2023 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 30 2023/ ...Synopsis... A robust upper wave is evident in mid-morning water-vapor imagery slowly shifting to the southeast across central/southern CA. Ahead of this wave, a broad swath of 50+ knot 500 mb flow is slowly overspreading the central/southern Rockies and the western Plains. A southerly low-level flow regime is noted across the Plains with a plume of 50+ F dewpoints advecting poleward through the southern Plains. This moisture will continue to move north through the period as a surface low deepens across parts of western KS/NE amid continued height falls and the approach of an upper-level jet streak late this afternoon into tonight. Broad isentropic ascent over the southern Plains and more focused ascent in the vicinity of the synoptic warm front and deepening surface low over the central Plains will support isolated to severe thunderstorms this afternoon and evening. ...Southern Plains... Regional radar mosaics over the past few hours show a steady increase in stratiform clouds and precipitation across parts of southwest TX. This is indicative of a broad warm advection regime that is expected to spread northeast into northern TX, eastern OK, and adjacent areas of AR/MO later this afternoon/evening. While 12 UTC soundings from OUN and FWD show marginal mid-level lapse rates, differential warming in the 850-700 mb layer through the day will support increasing buoyancy adequate for deep convection. Effective shear will generally increase through the period and may support a few organized elevated thunderstorms capable of large hail across eastern OK into AR/MO. Further west across northwest TX and southwest OK, a diffuse lee trough/dryline is expected to sharpen through the day as the deepening cyclone over the central Plains aids in advecting high-quality moisture northward from south TX and southwest downslope flow increases out of eastern NM. Initially capped soundings across northwest TX may see adequate daytime heating through broken clouds to allow for mixed-layer parcels to reach their LFCs within a weak dryline circulation. While this threat is highly conditional, the thermodynamic and kinematic environment would be supportive of supercells with all associated hazards. ...Central Plains... Surface pressure falls on the order of 2-3 mb/3 hours are noted across NE/IA this morning in the vicinity of a weak surface low and diffuse warm frontal zone across south-central NE to central IA. Steep mid-level lapse rates noted in 12 UTC soundings across the High Plains will advect westward through the day. The combination of increasing moisture, steepening lapse rates, and increasing ascent along the warm front should be favorable for isolated to scattered elevated convection across central NE into southeast SD late this afternoon/evening. Elongating hodographs will feature sufficient deep-layer shear for organized convection with an associated hail threat. Additional convection is expected to overspread much of the Mid-West during the overnight hours within a strengthening warm advection regime. Strong cells in this regime may produce small hail, but less favorable buoyancy/deep-layer shear with eastward extent and the potential for numerous storm interactions casts uncertainty into the severe threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Mar 30 2023 Valid 302000Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible this evening over parts of the central and southern Great Plains. No changes have been made to the outlook. See the previous discussion below for more information. ..Dean.. 03/30/2023 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 30 2023/ ...Synopsis... A robust upper wave is evident in mid-morning water-vapor imagery slowly shifting to the southeast across central/southern CA. Ahead of this wave, a broad swath of 50+ knot 500 mb flow is slowly overspreading the central/southern Rockies and the western Plains. A southerly low-level flow regime is noted across the Plains with a plume of 50+ F dewpoints advecting poleward through the southern Plains. This moisture will continue to move north through the period as a surface low deepens across parts of western KS/NE amid continued height falls and the approach of an upper-level jet streak late this afternoon into tonight. Broad isentropic ascent over the southern Plains and more focused ascent in the vicinity of the synoptic warm front and deepening surface low over the central Plains will support isolated to severe thunderstorms this afternoon and evening. ...Southern Plains... Regional radar mosaics over the past few hours show a steady increase in stratiform clouds and precipitation across parts of southwest TX. This is indicative of a broad warm advection regime that is expected to spread northeast into northern TX, eastern OK, and adjacent areas of AR/MO later this afternoon/evening. While 12 UTC soundings from OUN and FWD show marginal mid-level lapse rates, differential warming in the 850-700 mb layer through the day will support increasing buoyancy adequate for deep convection. Effective shear will generally increase through the period and may support a few organized elevated thunderstorms capable of large hail across eastern OK into AR/MO. Further west across northwest TX and southwest OK, a diffuse lee trough/dryline is expected to sharpen through the day as the deepening cyclone over the central Plains aids in advecting high-quality moisture northward from south TX and southwest downslope flow increases out of eastern NM. Initially capped soundings across northwest TX may see adequate daytime heating through broken clouds to allow for mixed-layer parcels to reach their LFCs within a weak dryline circulation. While this threat is highly conditional, the thermodynamic and kinematic environment would be supportive of supercells with all associated hazards. ...Central Plains... Surface pressure falls on the order of 2-3 mb/3 hours are noted across NE/IA this morning in the vicinity of a weak surface low and diffuse warm frontal zone across south-central NE to central IA. Steep mid-level lapse rates noted in 12 UTC soundings across the High Plains will advect westward through the day. The combination of increasing moisture, steepening lapse rates, and increasing ascent along the warm front should be favorable for isolated to scattered elevated convection across central NE into southeast SD late this afternoon/evening. Elongating hodographs will feature sufficient deep-layer shear for organized convection with an associated hail threat. Additional convection is expected to overspread much of the Mid-West during the overnight hours within a strengthening warm advection regime. Strong cells in this regime may produce small hail, but less favorable buoyancy/deep-layer shear with eastward extent and the potential for numerous storm interactions casts uncertainty into the severe threat. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0125 PM CDT Thu Mar 30 2023 Valid 311200Z - 011200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL/SOUTHERN PLAINS... Widespread critical fire-weather conditions are still expected tomorrow (Friday) afternoon and evening over portions of the Central/Southern Plains. Expansions to the Critical area were made in southwest KS, central NM, and central and West TX. Critical meteorological conditions are likely across northeastern OK and southeastern KS, but confidence in supportive fuels -- due to possible convective precipitation later today and tonight amidst already sub-critical levels -- precludes an extension of the Critical area in this update. Please see the previous discussion for more information. ..Flournoy/Squitieri.. 03/30/2023 .PREV DISCUSSION... /ISSUED 0203 AM CDT Thu Mar 30 2023/ ...Synopsis... A large-scale mid/upper-level trough, initially over the central/southern High Plains, will track east-northeastward into the Midwest/Great Lakes vicinity through the period, while a belt of strong deep-layer west-southwesterly flow overspreads the central/southern High Plains. At the same time, a related cold front will move eastward from the central Plains into the eastern CONUS. Within the post-frontal environment, an expansive area of high-end critical fire-weather conditions are expected across portions of the central and southern High Plains during the afternoon/early evening. ...Central/Southern High Plains... Behind the eastward-advancing cold front, mostly clear skies and strong downslope flow will yield 10-15 percent RH across the region. Related deep boundary-layer mixing into the strong flow aloft, combined with a tight surface pressure gradient, will support an expansive area of 25-35 mph sustained westerly surface winds (with gusts upwards of 45 mph). These conditions will favor widespread high-end critical conditions across much of the central/southern High Plains during the afternoon/early evening hours. And, the potential for extremely critical meteorological conditions is evident, especially from portions of southeastern CO into the TX/OK Panhandles. With that said, the current state of fuels does not appear to support an Extremely Critical area at this time. Farther east into north-central/northeastern OK and southeastern KS, critical meteorological conditions are possible; however, accumulating rainfall over already marginal fuels on Day 1/Thursday casts uncertainty on the overall fire-weather threat. Therefore, Elevated highlights remain in place for these areas, though Critical highlights could be needed if rainfall is less than anticipated. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0125 PM CDT Thu Mar 30 2023 Valid 311200Z - 011200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL/SOUTHERN PLAINS... Widespread critical fire-weather conditions are still expected tomorrow (Friday) afternoon and evening over portions of the Central/Southern Plains. Expansions to the Critical area were made in southwest KS, central NM, and central and West TX. Critical meteorological conditions are likely across northeastern OK and southeastern KS, but confidence in supportive fuels -- due to possible convective precipitation later today and tonight amidst already sub-critical levels -- precludes an extension of the Critical area in this update. Please see the previous discussion for more information. ..Flournoy/Squitieri.. 03/30/2023 .PREV DISCUSSION... /ISSUED 0203 AM CDT Thu Mar 30 2023/ ...Synopsis... A large-scale mid/upper-level trough, initially over the central/southern High Plains, will track east-northeastward into the Midwest/Great Lakes vicinity through the period, while a belt of strong deep-layer west-southwesterly flow overspreads the central/southern High Plains. At the same time, a related cold front will move eastward from the central Plains into the eastern CONUS. Within the post-frontal environment, an expansive area of high-end critical fire-weather conditions are expected across portions of the central and southern High Plains during the afternoon/early evening. ...Central/Southern High Plains... Behind the eastward-advancing cold front, mostly clear skies and strong downslope flow will yield 10-15 percent RH across the region. Related deep boundary-layer mixing into the strong flow aloft, combined with a tight surface pressure gradient, will support an expansive area of 25-35 mph sustained westerly surface winds (with gusts upwards of 45 mph). These conditions will favor widespread high-end critical conditions across much of the central/southern High Plains during the afternoon/early evening hours. And, the potential for extremely critical meteorological conditions is evident, especially from portions of southeastern CO into the TX/OK Panhandles. With that said, the current state of fuels does not appear to support an Extremely Critical area at this time. Farther east into north-central/northeastern OK and southeastern KS, critical meteorological conditions are possible; however, accumulating rainfall over already marginal fuels on Day 1/Thursday casts uncertainty on the overall fire-weather threat. Therefore, Elevated highlights remain in place for these areas, though Critical highlights could be needed if rainfall is less than anticipated. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Thu Mar 30 2023 Valid 311200Z - 011200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI...AND ALSO ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...EXTREME WESTERN KENTUCKY...WESTERN TENNESSEE...AND FAR NORTHWEST MISSISSIPPI... ...SUMMARY... Intense and widespread severe thunderstorms are expected Friday afternoon into the overnight hours across portions of the Middle Mississippi Valley and Mid-South vicinity, eastward to the Lower Ohio and Tennessee Valleys. Intense, damaging gusts and several tornadoes (some strong and long-track) are expected. ...A regional outbreak of severe storms is expected on Friday across parts of the Mid-Mississippi Valley and also into the Mid-South... ...Synopsis... A deep mid/upper-level trough and attendant 100 kt midlevel jet will move quickly eastward from the central Plains into parts of the MS Valley and Midwest on Friday. A surface low will deepen as it moves across IA toward the Great Lakes region, as a cold front sweeps eastward through parts of the Great Plains into the mid-MS Valley. In advance of the cold front, low-level moisture will stream northward across a broad warm sector from the ArkLaTex region into parts of the lower/mid MS Valley and Midwest. ...Mid-MS Valley vicinity into IN/lower MI... Rapid destabilization and increasing large-scale ascent will support thunderstorm development by early/mid afternoon across parts of IA into northern MO. Very strong deep-layer shear (effective shear in excess of 60 kt) and MLCAPE increasing to 1000-1500 J/kg (locally greater) will support organized convection, with initial supercell development expected somewhere over central IA into north-central MO. Very large hail will be the initial threat, given steep midlevel lapse rates and cold temperatures aloft. Some uncertainty remains regarding the convective mode evolution with time, but a few semi-discrete supercells are expected to move into an environment with stronger low-level shear/SRH across eastern IA into northwest IL by late afternoon, posing a threat for a couple strong tornadoes. Evolution into small clusters or bowing segments is expected, resulting in an increasing threat of severe/damaging winds in addition to a continued threat of a few tornadoes and sporadic hail. Organized convection will spread eastward into parts of IN/southern MI Friday night. Instability will weaken with eastward extent, but some threat for damaging wind and a couple of tornadoes will persist before a more definitive weakening trend occurs overnight into early Saturday morning. ...ArkLaTex/Mid South vicinity into the TN/lower OH Valleys... A concerning scenario still appears possible across portions of the MO Bootheel, northeast AR, western TN/KY and far northwest MS vicinity during the afternoon/evening. At least mid-60s F dewpoints are expected beneath modest midlevel lapse rates. This will support 1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by early afternoon. Thunderstorms are expected to develop by early afternoon ahead of the cold front within a pre-frontal trough/low-level confluence zone. Storm motion near 50 kt with supercell wind profiles will support cells capable of significant and long-track tornadoes. With time, upscale growth into a QLCS is expected, and intense wind gusts will be possible in addition to mesovortex tornadoes. The threat for damaging gusts and a few line-embedded tornadoes will spread into parts of the TN and lower OH Valleys Friday night, with a gradual weakening trend eventually expected overnight as storms move into increasingly weak buoyancy with eastward extent. ..Dean.. 03/30/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Thu Mar 30 2023 Valid 311200Z - 011200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI...AND ALSO ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...EXTREME WESTERN KENTUCKY...WESTERN TENNESSEE...AND FAR NORTHWEST MISSISSIPPI... ...SUMMARY... Intense and widespread severe thunderstorms are expected Friday afternoon into the overnight hours across portions of the Middle Mississippi Valley and Mid-South vicinity, eastward to the Lower Ohio and Tennessee Valleys. Intense, damaging gusts and several tornadoes (some strong and long-track) are expected. ...A regional outbreak of severe storms is expected on Friday across parts of the Mid-Mississippi Valley and also into the Mid-South... ...Synopsis... A deep mid/upper-level trough and attendant 100 kt midlevel jet will move quickly eastward from the central Plains into parts of the MS Valley and Midwest on Friday. A surface low will deepen as it moves across IA toward the Great Lakes region, as a cold front sweeps eastward through parts of the Great Plains into the mid-MS Valley. In advance of the cold front, low-level moisture will stream northward across a broad warm sector from the ArkLaTex region into parts of the lower/mid MS Valley and Midwest. ...Mid-MS Valley vicinity into IN/lower MI... Rapid destabilization and increasing large-scale ascent will support thunderstorm development by early/mid afternoon across parts of IA into northern MO. Very strong deep-layer shear (effective shear in excess of 60 kt) and MLCAPE increasing to 1000-1500 J/kg (locally greater) will support organized convection, with initial supercell development expected somewhere over central IA into north-central MO. Very large hail will be the initial threat, given steep midlevel lapse rates and cold temperatures aloft. Some uncertainty remains regarding the convective mode evolution with time, but a few semi-discrete supercells are expected to move into an environment with stronger low-level shear/SRH across eastern IA into northwest IL by late afternoon, posing a threat for a couple strong tornadoes. Evolution into small clusters or bowing segments is expected, resulting in an increasing threat of severe/damaging winds in addition to a continued threat of a few tornadoes and sporadic hail. Organized convection will spread eastward into parts of IN/southern MI Friday night. Instability will weaken with eastward extent, but some threat for damaging wind and a couple of tornadoes will persist before a more definitive weakening trend occurs overnight into early Saturday morning. ...ArkLaTex/Mid South vicinity into the TN/lower OH Valleys... A concerning scenario still appears possible across portions of the MO Bootheel, northeast AR, western TN/KY and far northwest MS vicinity during the afternoon/evening. At least mid-60s F dewpoints are expected beneath modest midlevel lapse rates. This will support 1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by early afternoon. Thunderstorms are expected to develop by early afternoon ahead of the cold front within a pre-frontal trough/low-level confluence zone. Storm motion near 50 kt with supercell wind profiles will support cells capable of significant and long-track tornadoes. With time, upscale growth into a QLCS is expected, and intense wind gusts will be possible in addition to mesovortex tornadoes. The threat for damaging gusts and a few line-embedded tornadoes will spread into parts of the TN and lower OH Valleys Friday night, with a gradual weakening trend eventually expected overnight as storms move into increasingly weak buoyancy with eastward extent. ..Dean.. 03/30/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Thu Mar 30 2023 Valid 301700Z - 311200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL/SOUTHERN HIGH PLAINS... The previous forecast remains on track regarding widespread critical fire-weather conditions developing today over portions of the central/southern High Plains. Only minor adjustments were made to the northeastern and southern peripheries of the Elevated/Critical areas. Mid-/upper-level clouds currently overspread portions of southeast NM. This cloud cover is expected to gradually clear and shift eastward, boosting diurnal heating and boundary-layer mixing to support critical conditions. Please see the previous discussion for more information. ..Flournoy/Squitieri.. 03/30/2023 .PREV DISCUSSION... /ISSUED 0202 AM CDT Thu Mar 30 2023/ ...Synopsis... A highly amplified mid/upper-level trough accompanied by strong deep-layer southwesterly winds will overspread the central/southern Rockies and adjacent High Plains. In response, a surface cyclone will rapidly deepen near northeastern CO, while a southward-extending dryline sharpens across the central/southern High Plains during the afternoon. By the evening hours, the surface cyclone will continue east-northeastward, while an attendant Pacific cold front overspreads the High Plains. This large-scale pattern will favor an expansive area of high-end critical fire-weather conditions across much of the central/southern High Plains during the afternoon/evening hours. ...Central/Southern High Plains... Behind the dryline, strong downslope warming/drying amid efficient diurnal heating will yield deep boundary-layer mixing and an expansive area of single-digit to lower teens RH. At the same time, southwesterly surface winds will rapidly strengthen in response to the tightening pressure gradient peripheral to the deepening surface cyclone. 20-30 mph sustained southwesterly surface winds are expected over most of the central/southern High Plains, and deep boundary-layer mixing into the strong flow aloft will support gusts upwards of 50 mph. These conditions will support the potential for rapid spread of any wildfires that develop. Over parts of eastern NM into southeastern CO, a corridor of 30+ mph sustained surface winds and single-digit RH could lead to extremely critical meteorological conditions; however, current indications are that fuels do not support Extremely Critical highlights. During the evening/overnight hours, strong westerly surface winds will overspread the risk area behind the Pacific cold front. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Wed Mar 29 21:07:01 UTC 2023.

MD 0383 CONCERNING SNOW SQUALL FOR NORTHERN PENNSYLVANIA AND NEW YORK
Mesoscale Discussion 0383 NWS Storm Prediction Center Norman OK 0405 PM CDT Wed Mar 29 2023 Areas affected...Northern Pennsylvania and New York Concerning...Snow Squall Valid 292105Z - 300100Z SUMMARY...Snow squalls will be possible through the evening hours across northern Pennsylvania and central/western New York as a cold front pushes across the region. DISCUSSION...A cold front tracking eastward across the lower Great Lakes region is beginning to move into portions of OH, PA, and western NY. While temperatures ahead of this front remain the upper 40s and low 50s, surface observations behind the front show temperatures quickly falling into the low 30s with moderate to heavy snow, visibility reductions between 1/2 to 1/4 mile, and strong wind gusts between 35-45 mph. Strong pressure rises behind the front are also noted west of the Buffalo, NY region, suggesting that the strongest frontal surge will occur across the western NY area for the next several hours. Snow squall conditions are expected to persist immediately behind this front as it continues east across northern PA and much of NY through the evening hours, and may extend as far east as the New England region during the overnight hours. ..Moore.. 03/29/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...CLE... LAT...LON 43247904 43907787 44957596 45147523 45137434 44907383 44397364 43517393 42657463 42017577 41527727 41347881 41377973 41768014 42318011 42627993 43247904 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Mar 29 2023 Valid 292000Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...20z Update... Widespread cloud cover and precipitation has thus far limited buoyancy over much of CA and the West Coast. Low topped storms may still develop over the central Valley later this afternoon, but confidence in severe potential remains low. Thunder has been trimmed farther north across OR and far northern CA where lingering cloud cover and weakening large-scale lift will limit thunder potential. In the lee of the Great Lakes, a band of low topped convective snow showers along the cold front will move into the northeastern US from southern Canada this evening. Snow squall conditions may develop along with a few lightning flashes. Otherwise, the previous forecast remains on track with minimal changes. See the previous discussion for additional information. ..Lyons/Jewell.. 03/29/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Mar 29 2023/ ...South Florida... Scattered thunderstorms should develop along both sea breezes during the late afternoon and may converge over the Everglades by early evening. Relatively modest low-level moisture and weaknesses in mid-level lapse rates per 12Z observed Miami/Key West soundings should hold MLCAPE below 1000 J/kg. A couple of the strongest updrafts may produce gusty winds and small hail across the southern portion of the Florida Peninsula. ...Lee of the Lower Great Lakes... A shortwave trough over the Upper Great Lakes will take on a negative tilt as it progresses across the Saint Lawrence Valley through Thursday morning. This will result in cyclogenesis over Quebec with a sharpening cold front trailing across southern Ontario, and pushing east in New York/Pennsylvania during the late afternoon and evening. Buoyancy will be minimal (MLCAPE <=100 J/kg) ahead of the front owing to surface dew points in the 20s. But the strengthening large-scale ascent should support a high-based, low-topped band of convection along the front. Increasing low-level flow behind the front will be mixed to the surface and yield gusty winds. Graupel and even a snow squall will be possible as temperatures tumble. ...Central/Southern California... The closed upper low off the coastal of northern California this morning will spread south-southeastward toward the central California coast through tonight. A few stronger low-topped thunderstorms could occur near the north-central Coast this afternoon and/or across the central Valley late this afternoon, pending cloud breaks/modest destabilization. For southern California, it still appears that severe-weather potential will remain low given the limited low-level moisture influx and weak destabilization inland. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0116 PM CDT Wed Mar 29 2023 Valid 301200Z - 311200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL/SOUTHERN HIGH PLAINS... The previous forecast remains on track regarding high-end critical fire-weather conditions developing over portions of the central/southern High Plains tomorrow (Friday) afternoon and evening. The Critical area has been expanded to the southwest to account for anticipated strong surface winds amidst relative humidities around 10 percent or lower. The potential for extremely critical meteorological surface conditions to materialize continues along a corridor from northeastern NM arcing south-southwestward through the El Paso Metro and vicinity. However, forecast fuel conditions in the region do not support an Extremely Critical area on Friday afternoon. Please see the previous discussion for more information. ..Flournoy/Squitieri.. 03/29/2023 .PREV DISCUSSION... /ISSUED 0205 AM CDT Wed Mar 29 2023/ ...Synopsis... A highly amplified mid/upper-level trough accompanied by strong deep-layer southwesterly flow will overspread the central/southern Rockies and adjacent High Plains. During the afternoon hours, a related surface cyclone will rapidly deepen near northeastern CO, while a dryline extends southward across the central/southern High Plains. Into the evening/overnight hours, the surface cyclone will continue eastward across the central Plains, while an attendant Pacific cold front overspreads the central/southern High Plains. This pattern will yield an expansive area of high-end critical conditions over portions of the southern/central High Plains. ...Southern and Central High Plains... Behind the dryline over the southern/central High Plains, deep boundary-layer mixing aided by strong downslope warming/drying and diurnal heating will yield an expansive area of single-digit to lower teens RH. While forecast soundings indicate the potential for lingering high clouds over parts of west TX, the strong downslope flow should easily compensate for this. At the same time, a rapidly tightening surface pressure gradient peripheral to the deepening surface low will support widespread 20-30 mph sustained southwesterly surface winds. And, the deep boundary-layer mixing into strong flow aloft will favor gusts upwards of 50 mph. These conditions will support high-end critical fire-weather conditions during the afternoon/evening hours. Over parts of eastern NM, sustained surface winds in excess of 30 mph could lead to extremely critical meteorological conditions; however, the current state of fuels does not support such highlights at this time. During the evening/overnight hours, a westerly wind shift can be expected behind the Pacific cold front, with winds remaining strong/gusty in the wake of the front. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Wed Mar 29 2023 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE SOUTHERN/CENTRAL PLAINS AND THE UPPER MIDWEST... ...SUMMARY... Isolated strong to severe storms are possible over parts of the southern and central Plains Thursday evening and overnight. ...Synopsis... Amplified mid-level flow is expected across much of the CONUS as an active flow regime continues. An anomalously deep upper-level cyclone over the West Coast is forecast to shift eastward across the Southwest as it transitions toward an open wave through Thursday. A lee cyclone over eastern CO should deepen as lift from the trough and an 80-90 kt jet streak overspreads the southern/central Rockies and High Plains. To the east, shortwave ridging over the Southeast will support broad southerly return flow across the center of the country. A warm front will rapidly lift poleward extending into KS/NE by the end of the period. Weak destabilization and strong shear near and south of the front may support isolated severe thunderstorms ahead of the deepening surface cyclone across the central and southern Great Plains Thursday evening into the overnight hours. ...Southern Plains... As the upper trough begins to eject eastward out of the Southwest over the Rockies and High Plains, large-scale ascent from the advancing polar jet streak/trough is forecast to generally lag behind the returning warm sector farther east. Despite rapid northward advection of upper 50s to low 60s F surface dewpoints, perhaps as far north as KS/OK by 00z, considerable inhibition is expected during the daylight hours across much of the southern Plains. This should generally suppress surface based thunderstorms until after sunset, though a conditional risk for a supercell will remain possible primarily across southwestern OK. A few elevated cells may develop with a small southern stream perturbation passing over portions of eastern OK with a risk for hail and or wind. Gradually increasing forcing for ascent ahead of the advancing Pacific front/dryline may allow for isolated thunderstorms to develop near the Red River in south-central/southeastern OK and track east northeastward overnight. While likely somewhat stable in the low levels, increasing vertical shear supportive of organized storms, including supercells, may promote a risk for isolated hail and damaging gusts. ...Central Plains and Midwest... Farther north, large-scale forcing will arrive earlier in the diurnal cycle across portions of eastern NE/SD into the upper Midwest, but the low-levels will remain mostly stable at the tip of the moist plume rapidly advecting north. As a result, limited buoyancy (generally less than 500 J/kg of MUCAPE) is expected despite steeper mid-level lapse rates beneath the cold core of the trough. Isolated elevated thunderstorms may develop late in the afternoon from eastern NE into southern SD capable of some severe hail given favorable shear profiles for supercells. As the main trough continues eastward, low-level mass response from the deepening surface low should allow for more widespread thunderstorms to develop after dark. Elevated thunderstorms should develop in an arc near the core of the low-level jet from western IA, toward southwestern MN. Severe hail may develop north of the warm front through the overnight and into early Friday Morning. Additional elevated thunderstorms are possible farther east over portions of northern and central IL, but confidence in severe potential here is lower owing to weaker forcing and more limited lapse rates aloft. ..Lyons/Jewell.. 03/29/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Mar 29 2023 Valid 291630Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...South Florida... Scattered thunderstorms should develop along both sea breezes during the late afternoon and may converge over the Everglades by early evening. Relatively modest low-level moisture and weaknesses in mid-level lapse rates per 12Z observed Miami/Key West soundings should hold MLCAPE below 1000 J/kg. A couple of the strongest updrafts may produce gusty winds and small hail across the southern portion of the Florida Peninsula. ...Lee of the Lower Great Lakes... A shortwave trough over the Upper Great Lakes will take on a negative tilt as it progresses across the Saint Lawrence Valley through Thursday morning. This will result in cyclogenesis over Quebec with a sharpening cold front trailing across southern Ontario, and pushing east in New York/Pennsylvania during the late afternoon and evening. Buoyancy will be minimal (MLCAPE <=100 J/kg) ahead of the front owing to surface dew points in the 20s. But the strengthening large-scale ascent should support a high-based, low-topped band of convection along the front. Increasing low-level flow behind the front will be mixed to the surface and yield gusty winds. Graupel and even a snow squall will be possible as temperatures tumble. ...Central/Southern California... The closed upper low off the coastal of northern California this morning will spread south-southeastward toward the central California coast through tonight. A few stronger low-topped thunderstorms could occur near the north-central Coast this afternoon and/or across the central Valley late this afternoon, pending cloud breaks/modest destabilization. For southern California, it still appears that severe-weather potential will remain low given the limited low-level moisture influx and weak destabilization inland. ..Guyer/Moore.. 03/29/2023 Read more

No watches are valid as of Tue Mar 28 20:16:01 UTC 2023.