Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Jul 19 2023 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE UPPER MIDWEST...AND EASTERN NORTH CAROLINA INTO SOUTHEASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms capable of producing damaging winds and hail are expected this afternoon into tonight across parts of the Upper Midwest, central Plains, and Mid Atlantic regions. More isolated strong to severe thunderstorms may also occur from the Ozarks into the lower Ohio and Tennessee Valleys, and parts of the Great Basin. ...20Z Update... The Slight Risk has been expanded across parts of eastern NC based on recent convective trends. See Mesoscale Discussion 1628 for more details on the near-term severe threat for this area. Have trimmed the Marginal Risk across parts of the TN and lower OH Valley. There still appears to be some potential for strong to locally severe thunderstorms late tonight into early Thursday morning over portions of this region as convection spreads eastward in a modest low-level warm advection regime ahead of an approaching upper trough. Small adjustments have also been made to the Marginal/Slight Risk areas across the mid MO Valley into eastern SD/western MN based on observational and short-term model trends. ..Gleason.. 07/19/2023 .PREV DISCUSSION... /ISSUED 1121 AM CDT Wed Jul 19 2023/ ...MN/WI... An upper low is tracking southeastward out of southern Manitoba into ND. At the surface, a quasi-stationary boundary extends from northwest MN southward to near MSP. Westerly low-level winds and strong heating west of the boundary, combined with backed flow to the east and more persistent low-level moisture, will lead to an axis of thunderstorm development this afternoon. Forecast soundings show low-level and deep-layer shear profiles favorable for rotating storms capable of hail and gusty winds. A tornado or two is also possible. These storms will drift eastward into the MN Arrowhead region and northern WI during the evening. ...Central Plains... A broad upper ridge is positioned from the Four Corners region eastward across the southeast states today, with the southern fringe of stronger westerlies extending across CO/KS. Rich low-level moisture is present across much of the central Plains, with dewpoints in the upper 60s and 70s from eastern CO into central NE. Thunderstorms are expected to develop along the western edge of the greater moisture by mid-afternoon along an axis from north-central NE into northwest KS and eastern CO. These storms will spread southeastward through the evening, posing a risk of very large hail and damaging winds. Activity is expected to build as far south as parts of the TX/OK Panhandles during the evening. ...KS/MO... Multiple 12z CAM solutions suggest that a cluster of storms over northern KS will grow upscale and become very organized late tonight, resulting in a corridor of severe wind potential from eastern KS across central into southeast MO. At this point, the confidence in this scenario remains low but will be monitored. ...VA/NC... A remnant MCV is evident in satellite/radar imagery over north-central NC. The associated cluster of thunderstorms will track northeastward toward the coast this afternoon, posing a risk of damaging wind gusts. Please refer to MCD #1627 for further details. ...UT... A cluster of showers and thunderstorms over western NV is associated with a weak mid-level shortwave trough. Weak but sufficient forcing ahead of this system will lead to scattered thunderstorm development later today over eastern NV and western UT. Forecast soundings show inverted-v profiles, but with pockets of CAPE around 500-1000 J/kg and with 25-30 knots of westerly mid-level flow. This will be sufficient to pose a risk of locally severe wind gusts in the stronger cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Jul 19 2023 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE UPPER MIDWEST...AND EASTERN NORTH CAROLINA INTO SOUTHEASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms capable of producing damaging winds and hail are expected this afternoon into tonight across parts of the Upper Midwest, central Plains, and Mid Atlantic regions. More isolated strong to severe thunderstorms may also occur from the Ozarks into the lower Ohio and Tennessee Valleys, and parts of the Great Basin. ...20Z Update... The Slight Risk has been expanded across parts of eastern NC based on recent convective trends. See Mesoscale Discussion 1628 for more details on the near-term severe threat for this area. Have trimmed the Marginal Risk across parts of the TN and lower OH Valley. There still appears to be some potential for strong to locally severe thunderstorms late tonight into early Thursday morning over portions of this region as convection spreads eastward in a modest low-level warm advection regime ahead of an approaching upper trough. Small adjustments have also been made to the Marginal/Slight Risk areas across the mid MO Valley into eastern SD/western MN based on observational and short-term model trends. ..Gleason.. 07/19/2023 .PREV DISCUSSION... /ISSUED 1121 AM CDT Wed Jul 19 2023/ ...MN/WI... An upper low is tracking southeastward out of southern Manitoba into ND. At the surface, a quasi-stationary boundary extends from northwest MN southward to near MSP. Westerly low-level winds and strong heating west of the boundary, combined with backed flow to the east and more persistent low-level moisture, will lead to an axis of thunderstorm development this afternoon. Forecast soundings show low-level and deep-layer shear profiles favorable for rotating storms capable of hail and gusty winds. A tornado or two is also possible. These storms will drift eastward into the MN Arrowhead region and northern WI during the evening. ...Central Plains... A broad upper ridge is positioned from the Four Corners region eastward across the southeast states today, with the southern fringe of stronger westerlies extending across CO/KS. Rich low-level moisture is present across much of the central Plains, with dewpoints in the upper 60s and 70s from eastern CO into central NE. Thunderstorms are expected to develop along the western edge of the greater moisture by mid-afternoon along an axis from north-central NE into northwest KS and eastern CO. These storms will spread southeastward through the evening, posing a risk of very large hail and damaging winds. Activity is expected to build as far south as parts of the TX/OK Panhandles during the evening. ...KS/MO... Multiple 12z CAM solutions suggest that a cluster of storms over northern KS will grow upscale and become very organized late tonight, resulting in a corridor of severe wind potential from eastern KS across central into southeast MO. At this point, the confidence in this scenario remains low but will be monitored. ...VA/NC... A remnant MCV is evident in satellite/radar imagery over north-central NC. The associated cluster of thunderstorms will track northeastward toward the coast this afternoon, posing a risk of damaging wind gusts. Please refer to MCD #1627 for further details. ...UT... A cluster of showers and thunderstorms over western NV is associated with a weak mid-level shortwave trough. Weak but sufficient forcing ahead of this system will lead to scattered thunderstorm development later today over eastern NV and western UT. Forecast soundings show inverted-v profiles, but with pockets of CAPE around 500-1000 J/kg and with 25-30 knots of westerly mid-level flow. This will be sufficient to pose a risk of locally severe wind gusts in the stronger cells. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Jul 19 2023 Valid 201200Z - 211200Z ...NO CRITICAL AREAS... No changes, the previous forecast discussion remains valid. ..Lyons.. 07/19/2023 .PREV DISCUSSION... /ISSUED 0200 AM CDT Wed Jul 19 2023/ ...Synopsis... Upper-level ridging will remain the dominant feature across the West on Thursday. This ridge may shift slightly eastward through the period. As this occurs, stronger mid-level winds will move inland in the Northwest late Thursday into Friday. At the surface, the pressure pattern will remain nebulous across the West. However, a surface thermal pressure trough will likely develop into the Columbia Basin. Fire weather concerns will again be minimal across the U.S. on account of weak surface. Hot and dry conditions will continue in the Southwest, Great Basin, and Northwest. Some locally elevated conditions could occur in terrain-favored areas. Flow through the Cascade gaps and Columbia Gorge will likely increase as the trough approaches. The increase in surface winds will not occur during the diurnal RH minimum though. While mid-level moisture is expected to be pushed east, a few thunderstorms are possible from eastern Nevada into western Colorado. Fuels are still not expected to be critically dry and storm coverage will be lower than previous days. Confidence in lightning ignitions remains too low for highlights. ...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 1230 PM CDT Wed Jul 19 2023 Valid 201200Z - 211200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL HIGH PLAINS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES/OHIO VALLEY...AND THE CAROLINAS... ...SUMMARY... Scattered severe thunderstorms should occur Thursday across parts of the central/southern High Plains, Great Lakes/Ohio Valley, and parts of the Carolinas. The greatest concentration of severe wind may occur over parts of southeastern Colorado into southwestern Kansas and the Oklahoma Panhandle. ...Central/Southern High Plains... The western portion of a cold front will likely stall and become draped across eastern CO during the day. Easterly low-level flow will again favor seasonably moist conditions across the central High Plains with thunderstorm development expected by midday into the early afternoon along/near the CO Front Range. Convection should move east of the higher terrain during the early/mid afternoon and gradually intensify. Various model guidance shows elongated hodographs which will be favorable for organized thunderstorms, including supercells early in the convective life cycle. Large hail should be the main severe threat initially. Increasing coverage late Thursday afternoon/evening will likely favor a cluster/MCS to develop and potentially track east-southeastward near the boundary across southeastern CO/southwestern KS and perhaps into the OK/TX Panhandles during the evening, with a wind threat perhaps continuing into the late night near the OK/KS border. Given increased confidence in this MCS scenario occurring, have added greater severe wind probabilities and an Enhanced Risk. ...Great Lakes/Ohio Valley... Although details remain uncertain, isolated to scattered showers/thunderstorms may be ongoing across parts of KY/TN Thursday morning in association with enhanced mid-level westerly flow moving across this area. Still, a moist low-level airmass will destabilize where cloud breaks occur ahead of a southeastward-moving front. Various NAM/RAP forecast soundings across the Great Lakes and Ohio Valley ahead of the front show potential for organized storms given adequate instability and deep-layer shear. The more intense convection will be capable of scattered severe/damaging winds, in addition to the possibility of large hail and a tornado with any supercells. Overall thunderstorm coverage will probably be greatest over the OH Valley in association with the eastward-moving upper trough, with weaker low-level convergence potentially limiting coverage over mid the MS Valley into the Ozarks. Have expanded the Slight Risk across parts of Lower MI and into northwestern PA and vicinity, where latest guidance shows sufficient destabilization should occur to support surface-based thunderstorms and increased potential for severe hail/damaging winds. ...Carolinas... Strong heating of a moist airmass ahead of a lead disturbance will promote moderate to strong instability by early Thursday afternoon. Modest ascent should aid in the development of scattered storms by mid to late afternoon. Damaging gusts with the more organized multicells should be the primary concern, especially if a belt of stronger 2-4 km flow (30-40+ kt) is realized. This activity will likely weaken by Thursday evening. ..Gleason.. 07/19/2023 Read more

WW 0513 Status Updates
STATUS FOR WATCH 0513 HAS NOT BEEN ISSUED YET Read more

WW 513 SEVERE TSTM AR MS TN 182140Z - 190500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 513 NWS Storm Prediction Center Norman OK 440 PM CDT Tue Jul 18 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Arkansas Northern Mississippi Southwestern Tennessee * Effective this Tuesday afternoon from 440 PM until Midnight CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Another strong-severe thunderstorm complex, this one initially over northeastern AR, is expected to move southeastward near an outflow boundary from the earlier activity. Damaging to severe gusts and isolated large hail are the primary concerns. The severe thunderstorm watch area is approximately along and 75 statute miles east and west of a line from 45 miles west northwest of Jackson TN to Oxford MS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 511...WW 512... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 32035. ...Edwards Read more

MD 1620 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR FAR WESTERN TENNESSEE...NORTHEAST ARKANAS...AND NORTHERN MISSISSIPPI
Mesoscale Discussion 1620 NWS Storm Prediction Center Norman OK 0429 PM CDT Tue Jul 18 2023 Areas affected...far western Tennessee...northeast Arkanas...and northern Mississippi Concerning...Severe potential...Watch likely Valid 182129Z - 190000Z Probability of Watch Issuance...80 percent SUMMARY...At least isolated damaging gusts or marginal hail will remain possible for a few more hours, and a new watch is likely. DISCUSSION...Radar shows a decelerating outflow boundary extending from extreme northeast AR to just northeast of the Memphis TN area. Recent trends indicate strengthening storms on the southern fringe/outflow of the southeast MO MCS, with impressive echo IR presentation. Surface analysis confirms a very moist and unstable air mass remains in place south of the AR activity and west of the TN outflow, with dewpoints approaching 80 F in spots. Given the uncapped air mass and robust convection now ongoing over northeast AR, a new watch will likely be issued downstream extending into parts of western TN and northern MS. ..Jewell/Edwards.. 07/18/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MEG...LZK... LAT...LON 35999133 35959060 35938999 35878980 35768951 35438910 35178843 34798820 34428837 34228879 34328973 34579039 35029085 35589130 35999133 Read more

MD 1619 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN OHIO...EASTERN KENTUCKY...NORTHERN WEST VIRGINIA
Mesoscale Discussion 1619 NWS Storm Prediction Center Norman OK 0347 PM CDT Tue Jul 18 2023 Areas affected...Southern Ohio...Eastern Kentucky...Northern West Virginia Concerning...Severe potential...Watch unlikely Valid 182047Z - 182245Z Probability of Watch Issuance...20 percent SUMMARY...Scattered strong thunderstorms will continue through the afternoon. Present indications are that severe threat may remain relatively disorganized and may not require a WW. DISCUSSION...Radar/satellite imagery shows scattered thunderstorms slowly intensifying over portions of southern Ohio and eastern Kentucky. This development is occurring in a region of a warm/humid air mass with dewpoints in the upper 60s and MLCAPE values currently ranging from 2500-3000 J/kg. Moderately strong winds aloft are also present in this region, with sufficient effective shear for organized multicell or transient supercell structures. Despite the rather favorable environment, storms in eastern KY have been slow to become intense with no ground truth reports of wind damage so far. Given weak forcing, it is unclear whether sufficient coverage of severe activity will warrant a watch. Trends will be closely monitored. ..Hart/Bunting.. 07/18/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PBZ...RLX...JKL...ILN...LMK... LAT...LON 38248517 39268413 39928173 39658034 38168151 37288376 38248517 Read more

WW 0511 Status Updates
STATUS REPORT ON WW 511 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SW CKV TO 25 ESE CKV TO 15 SE OWB TO 25 SW EVV. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1618 ..WEINMAN..07/18/23 ATTN...WFO...LMK...PAH...JKL...OHX... STATUS REPORT FOR WS 511 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC001-003-009-021-027-029-031-045-053-057-059-061-085-087-091- 093-099-101-123-137-141-147-155-163-169-171-179-183-199-207-213- 217-227-229-231-182140- KY . KENTUCKY COUNTIES INCLUDED ARE ADAIR ALLEN BARREN BOYLE BRECKINRIDGE BULLITT BUTLER CASEY CLINTON CUMBERLAND DAVIESS EDMONSON GRAYSON GREEN HANCOCK HARDIN HART HENDERSON LARUE LINCOLN LOGAN MCCREARY MARION MEADE METCALFE MONROE NELSON OHIO PULASKI RUSSELL SIMPSON TAYLOR WARREN WASHINGTON WAYNE TNC003-015-021-027-031-035-037-041-043-049-055-061-081-085-087- 099-101-111-117-119-133-135-137-141-147-149-159-165-169-175-177- Read more

WW 511 SEVERE TSTM KY TN 181810Z - 190100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 511 NWS Storm Prediction Center Norman OK 110 PM CDT Tue Jul 18 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western and central Kentucky Western and middle Tennessee * Effective this Tuesday afternoon and evening from 110 PM until 800 PM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...A line of severe thunderstorms will move rapidly across the watch area this afternoon with the potential for damaging wind gusts to 75 mph. A tornado or two is also possible, in addition to isolated reports of large hail. The severe thunderstorm watch area is approximately along and 75 statute miles north and south of a line from 55 miles north northeast of Crossville TN to 10 miles west northwest of Fort Campbell KY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 510... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28045. ...Bunting Read more

WW 0512 Status Updates
STATUS FOR WATCH 0512 HAS NOT BEEN ISSUED YET Read more

WW 512 SEVERE TSTM AL GA TN 182040Z - 190300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 512 NWS Storm Prediction Center Norman OK 340 PM CDT Tue Jul 18 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Alabama Northwest Georgia Middle Tennessee * Effective this Tuesday afternoon and evening from 340 PM until 1000 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...A line of severe thunderstorms will continue moving east-southeast across the watch area through this evening with a risk for damaging wind gusts and isolated large hail. A tornado or two will also be possible. The severe thunderstorm watch area is approximately along and 40 statute miles north and south of a line from 35 miles southwest of Muscle Shoals AL to 15 miles south of Chattanooga TN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 510...WW 511... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 28040. ...Bunting Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Jul 18 2023 Valid 182000Z - 191200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered to numerous damaging winds are expected to continue this afternoon and early evening into the Tennessee and lower Ohio Valleys. Other strong to severe storms should occur across parts of the Northeast and northern/central Plains. ...20Z Update... Severe probabilities have been adjusted from the eastern portions of the central Plains into the mid MS Valley and lower OH Valley in the wake of the ongoing MCS across KY/TN. Scattered to numerous severe/damaging winds remain likely with this MCS as it continues eastward across the TN and lower OH Valleys this afternoon and early evening. See Mesoscale Discussion 1618 for more details on the near-term severe threat across this area. Some potential for redevelopment later this evening and overnight remains across parts of MO and vicinity in a strengthening low-level warm advection regime. Large hail may occur with any supercell that can form in this environment, and severe/damaging winds appears possible with any convection that can grow upscale into a cluster. Have therefore maintained the Slight Risk across portions of this area. A Slight Risk has also been introduced over the Black Hills of western SD into parts of northern NE. While overall thunderstorm coverage may remain fairly isolated across this region, any convection that can be sustained will likely be supecellular given 2000-2500+ J/kg of MLCAPE and 40-50 kt of deep-layer shear. Isolated very large (2+ inch) hail and severe wind gusts should be the main threats. ..Gleason.. 07/18/2023 .PREV DISCUSSION... /ISSUED 1134 AM CDT Tue Jul 18 2023/ ...Middle/Lower Missouri Valley to Tennessee Valley... Ongoing bowing complex of strong/severe storms continues moving southeast at 40-45 kt across southeast MO. Downstream heating of a very moist environment (dew points 75-80 Deg F) and seasonably strong mid-level northwesterly flow averaging 40-45 kts is expected to result in a continued southeast movement into an increasingly favorable environment for a forward-propagating MCS/potential for significant severe gusts. Please refer to recently-issued MCD 1613 for the latest short-term thinking in this area. Additionally, another round of elevated thunderstorms is expected to develop later today along the convectively influenced northwest/southeast-oriented boundary across Missouri. This may include elevated supercells with a threat for large (isolated very large) hail given strong elevated instability and substantial deep layer shear. With time, upscale growth will be possible and a severe wind threat could materialize. ...Northern Plains... Low-level moisture advection and surface heating will lead to moderate-strong instability across central North Dakota and South Dakota by this afternoon. This instability, combined with convergence from an approaching/sharpening cold front and ascent with a mid-level shortwave trough, should be sufficient for strong/severe thunderstorm development near the front this afternoon. Mid-level winds of 45-55 kt will contribute to favorable wind profiles for supercells and related risk for large hail, some potentially 2+ inches in diameter. ...Northeast/Mid-Atlantic States and New England... Modest height falls will continue to overspread the region, influenced by moderately strong cyclonic mid-level flow with an upper-level trough over northern Ontario/Quebec. Relatively long hodographs during peak heating/maximized instability will support some potential for sustained/organized storms capable of wet microbursts and isolated wind damage. Some hail will also be possible. Refer to MCD 1614 for short-term thinking in this area. ...Central High Plains... A few thunderstorms are possible late this afternoon as low-level upslope flow evolves, with increasing low-level moisture to the north of a surface low. The favorable environment may be relatively short-lived given the late-day increase in moisture, but a favorable environment will exist for a few severe thunderstorms in an environment with 2000+ J/kg MLCAPE and supercell wind profiles. ...Great Basin... A deeply mixed boundary layer is expected today across the Great Basin with ample instability for scattered thunderstorms across much of the region. A belt of stronger mid-level winds of 25-30 kt will exist from east-central Nevada into north-central Utah. This may support some storm organization with the potential for isolated strong/severe wind gusts given the well-mixed sub-cloud layer/steep low-level lapse rates. ...Southern Arizona... Thunderstorms should develop over the Rim/White Mountains and higher terrain of southeast Arizona this afternoon. The region will be nearly coincident with the upper high. While mid-level steering flow will be weak, a westerly component of near-surface winds will likely support propagation into the desert floor, particularly across southeast Arizona within a relatively moist but hot/deeply mixed boundary layer. Some strong, potentially severe outflow winds may occur late this afternoon/early evening. Read more

WW 0510 Status Updates
STATUS REPORT ON WW 510 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 SE ARG TO 30 SSE PAH TO 35 ENE PAH. ..WEINMAN..07/18/23 ATTN...WFO...MEG...LZK...PAH...LSX...SGF... STATUS REPORT FOR WS 510 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC093-182040- AR . ARKANSAS COUNTIES INCLUDED ARE MISSISSIPPI KYC035-055-075-083-105-143-157-221-182040- KY . KENTUCKY COUNTIES INCLUDED ARE CALLOWAY CRITTENDEN FULTON GRAVES HICKMAN LYON MARSHALL TRIGG MOC069-155-182040- MO . MISSOURI COUNTIES INCLUDED ARE DUNKLIN PEMISCOT Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0136 PM CDT Tue Jul 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains valid with no changes. The threat for widespread fire-weather concerns is low. Please see the prior discussion. ..Lyons.. 07/18/2023 .PREV DISCUSSION... /ISSUED 0115 AM CDT Tue Jul 18 2023/ ...Synopsis... The upper-level ridge across the West will amplify and extend into more of the Canadian Rockies on Wednesday. At the surface, the pressure pattern will generally become more diffuse in the West. Mid-level moisture will remain underneath the ridge in the Great Basin and Southwest. With the weak surface winds expected, only locally elevated fire weather concerns are expected. This will primarily occur in the Southwest and southern Great Basin where fuels are dry. Mixed wet/dry thunderstorms are again expected in part of the Great Basin. The greatest coverage of storms will likely occur over central/northern Nevada and northern Utah. Storm motions may be similar to perhaps slightly slower than on Tuesday. PWAT values, though, will remain near an inch. The overall threat for ignitions still appears too low for highlights. ...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 1230 PM CDT Tue Jul 18 2023 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... Scattered severe thunderstorms capable of producing large to very large hail and damaging winds appear possible Wednesday from the central Plains into the Upper Midwest. Isolated strong to severe thunderstorms may also occur from the Ozarks into the lower Ohio and Tennessee Valleys, along with the Carolinas and Mid-Atlantic. ...Synopsis... Upper ridging will remain confined to parts of the Northwest, Southwest, and southern Plains on Wednesday. A mid/upper-level trough/low is forecast to move from central Canada and the northern Plains across the Upper Midwest and Great Lakes through the period. A belt of enhanced (35-50+ kt) mid-level northwesterly flow should persist across these regions, and into parts of the mid MS and OH Valleys. A separate upper trough should progress over the eastern U.S. through the day. Multiple low-amplitude, convectively enhanced mid-level perturbations should advance generally east-southeastward within the west-northwesterly flow regime that will remain over much of the central/eastern CONUS. ...Northern/Central Plains into the Upper Midwest and Ozarks... As the upper trough/low moves east-southeastward, isolated to scattered thunderstorms will likely develop along and east/southeast of a cold front. Diurnal heating of a moist low-level airmass will foster the development of moderate to locally strong instability from parts of MN into southeastern SD, NE, and northwestern IA. Deep-layer shear of 40-50 kt will easily support supercells, with associated threat for both large hail and severe wind gusts. Isolated very large hail appears possible across parts of central/eastern NE and eastern MN/western WI with this activity. Based on consensus of latest guidance, have introduced a fairly broad Slight Risk to account for this supercell potential. The eastern extent of the severe risk should be modulated by the narrow zone of greater low-level moisture return. The southern extent of supercell potential into KS is rather uncertain, as large-scale ascent becomes increasingly modest into the central Plains. Still, there appears to be some risk for intense convection to develop/spread southeastward from NE into at least northern KS through Wednesday evening. Some potential also exists for a cluster of thunderstorms producing severe/damaging winds to spread from eastern CO into KS and perhaps eventually parts of MO Wednesday evening/night. ...Carolinas into the Mid-Atlantic... At least isolated thunderstorms may be ongoing Wednesday morning across parts of the Carolinas and Mid-Atlantic. Cloud cover and poor lapse rates may tend to limit the development of substantial instability until late Wednesday afternoon. Still, at least moderate instability should eventually develop and support robust updrafts. Better chances for strong to severe convection appear to exist along/east of a weak surface trough across eastern NC/VA/MD and vicinity. Occasional damaging winds should be the main threat with this activity, as deep-layer shear appears adequate for mainly multicells and small clusters. But, some hail may also occur with the strongest updrafts. Based on latest guidance, have expanded the Marginal Risk across this region to include more of eastern NC/SC and the Delmarva. ...Kentucky/Tennessee and Vicinity... Isolated to scattered thunderstorms may be present at the start of the period across this region. This activity may pose at least an isolated threat for severe hail and damaging winds, as deep-layer shear appears strong enough to support supercells. Most guidance shows a weakening trend to this morning convection. The potential for additional robust convective development in the wake of the morning thunderstorms is highly uncertain. But, some chance exists for renewed convection Wednesday afternoon/night along and south of a weak front. The environment will conditionally support a threat for all severe hazards, as enhanced northwesterly flow aloft appears sufficient for supercells. Have opted to include a fairly broad Marginal Risk across KY/TN and vicinity to account for potentially multiple rounds of strong to severe thunderstorms through the period. ..Gleason.. 07/18/2023 Read more

WW 0507 Status Updates
STATUS FOR WATCH 0507 HAS NOT BEEN ISSUED YET Read more

WW 507 SEVERE TSTM AR MO MS TN 172145Z - 180500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 507 NWS Storm Prediction Center Norman OK 445 PM CDT Mon Jul 17 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central, northern and eastern Arkansas Missouri Bootheel Northern Mississippi Western Tennessee * Effective this Monday afternoon from 445 PM until Midnight CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Clusters of strong-severe thunderstorms should move out of the main body of Missouri and into a large reservoir of favorable instability and moisture across the Mid-South, offering sporadic severe gusts and large hail. Some lateral expansion and new development across AR and/or TN also may occur. The severe thunderstorm watch area is approximately along and 80 statute miles north and south of a line from 15 miles west of Russellville AR to 45 miles east southeast of Jackson TN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 503...WW 504...WW 505...WW 506... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 33030. ...Edwards Read more

WW 0505 Status Updates
STATUS REPORT ON WW 505 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..07/17/23 ATTN...WFO...ILX...PAH...IND...IWX...ILN... STATUS REPORT FOR WS 505 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC019-021-023-025-029-033-035-041-045-047-049-055-065-079-081- 101-115-139-145-147-159-173-183-185-191-193-172240- IL . ILLINOIS COUNTIES INCLUDED ARE CHAMPAIGN CHRISTIAN CLARK CLAY COLES CRAWFORD CUMBERLAND DOUGLAS EDGAR EDWARDS EFFINGHAM FRANKLIN HAMILTON JASPER JEFFERSON LAWRENCE MACON MOULTRIE PERRY PIATT RICHLAND SHELBY VERMILION WABASH WAYNE WHITE INC005-009-011-013-015-021-023-027-029-031-035-041-045-047-051- 053-055-057-059-063-065-067-071-075-079-081-083-093-095-097-101- 105-107-109-119-121-125-129-133-135-137-139-145-153-157-159-161- 165-167-171-177-172240- IN . INDIANA COUNTIES INCLUDED ARE BARTHOLOMEW BLACKFORD BOONE Read more

WW 505 SEVERE TSTM IL IN 172030Z - 180400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 505 NWS Storm Prediction Center Norman OK 430 PM EDT Mon Jul 17 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern and eastern Illinois Central and southern Indiana * Effective this Monday afternoon from 430 PM until Midnight EDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Scattered severe thunderstorms will move east-southeast across the watch area through this evening with a risk for damaging wind gusts and large hail. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 25 miles southwest of Mattoon IL to 40 miles southeast of Muncie IN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 503...WW 504... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 28030. ...Bunting Read more