Severe Storms

MD 1507 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF NORTHERN/EASTERN MO INTO A SMALL PART OF WESTERN IL
Mesoscale Discussion 1507 NWS Storm Prediction Center Norman OK 0459 PM CDT Wed Jul 12 2023 Areas affected...Parts of northern/eastern MO into a small part of western IL Concerning...Severe potential...Watch unlikely Valid 122159Z - 122330Z Probability of Watch Issuance...20 percent SUMMARY...Storms may intensify into early evening as they move southeastward, with a threat of isolated hail and damaging gusts. DISCUSSION...Thunderstorms have recently developed in northern MO. Based on satellite and mesoanalysis data, this activity is clearly elevated, and likely will remain so in the short term, given substantial MLCINH across the region. However, even for elevated convection that is likely based around 800 mb, MUCAPE in excess of 1500 J/kg and sufficient deep-layer shear (supported by rather strong midlevel west-northwesterlies) conditionally favor the potential for a few organized storms. If any stronger cells/clusters can mature and be sustained into the early evening, some severe threat may evolve with this activity. Steep midlevel lapse rates will favor some hail potential, while a relatively warm and well-mixed boundary layer could support isolated damaging gusts, despite the relatively strong MLCINH. Uncertainty remains rather high regarding the evolution of this convection into the early evening, given its elevated nature and relative lack of stronger large-scale ascent across the area. Watch issuance is currently considered unlikely, but will become possible if organized storms develop or appear imminent. ..Dean/Guyer.. 07/12/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...EAX... LAT...LON 38009052 39109345 39569350 39899337 39789219 39569145 39249070 39049034 38648961 38388969 38109003 38009052 Read more

WW 0477 Status Updates
STATUS FOR WATCH 0477 HAS NOT BEEN ISSUED YET Read more

WW 477 TORNADO IL IN LM 122050Z - 130300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 477 NWS Storm Prediction Center Norman OK 350 PM CDT Wed Jul 12 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Northern Illinois Extreme northwest Indiana Lake Michigan * Effective this Wednesday afternoon and evening from 350 PM until 1000 PM CDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Scattered damaging wind gusts to 70 mph possible Isolated very large hail events to 2 inches in diameter possible SUMMARY...Isolated supercell severe thunderstorms are expected to develop and move east-southeast with a risk for a few tornadoes, large hail and damaging thunderstorm wind gusts. The potential also exists for a strong tornado or two to occur. The tornado watch area is approximately along and 45 statute miles north and south of a line from 35 miles southwest of Rockford IL to 10 miles north northeast of Valparaiso IN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and 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. && AVIATION...Tornadoes and 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 450. Mean storm motion vector 28030. ...Bunting Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Wed Jul 12 2023 Valid 122000Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN ILLINOIS/FAR NORTHWESTERN INDIANA...AND PARTS OF EASTERN KANSAS INTO MISSOURI... ...SUMMARY... Severe thunderstorms remain possible across much of Missouri, Illinois, and adjacent portions of the central Plains and Midwest this afternoon through tonight. A few tornadoes should occur this afternoon and evening across parts of northern Illinois into far northwestern Indiana, with a strong tornado possible. Otherwise, damaging winds and large hail should occur with intense thunderstorms that develop, with some potential for significant (75+ mph) severe winds and very large hail across parts of Missouri and Kansas. ...20Z Update... Primary change with this update was to introduce higher tornado probabilities in a narrow corridor across northern IL and far northwestern IN, including Chicago. Recent VWPs from KLOT show impressive low-level shear (0-1 km 35-40+ kt) and enlarged/curved low-level hodographs associated with a focused low-level jet. In the wake of a remnant MCS and lessening precipitation shield, it appears increasingly likely based on recent visible satellite imagery and surface observations that sufficient destabilization to support surface-based convection will occur across this region over the next few hours. Given the very favorable low-level and deep-layer shear available, concern has increased that any supercell which forms in this environment will be capable of producing a tornado. Some potential will exist for a strong tornado as effective SRH strengthens to around 250-350 m2/s2 along/near the developing warm front. The Slight Risk has also been expanded northward in southern Lower MI to account for a small bowing cluster which may develop. No changes have been made to the Enhanced Risk across parts of eastern KS into MO. 18Z sounding from TOP showed warm low/mid-level temperatures and a cap which should continue to inhibit robust convection for at least a couple more hours. Still, intense thunderstorm development is expected later this evening in tandem with a modestly strengthening low-level jet. ..Gleason.. 07/12/2023 .PREV DISCUSSION... /ISSUED 1140 AM CDT Wed Jul 12 2023/ ...Northern IL/southern WI east to northwest OH/southern lower MI... Current MCS continues a general weakening trend based on IR cloud tops, radar trends and recent reports. Air mass recovery in the wake of the morning convection currently appears plausible, aided by a modestly enhanced low-level jet later this afternoon and evening. Steepening mid-level lapse rates will contribute to moderate/pockets of strong MLCAPE this afternoon, and coupled with 40-50 kts of deep-layer shear would result in a favorable parameter space for supercell development by late afternoon/early evening with all severe hazards possible. Will introduce a small 5 percent tornado probability area across this region, where forecast sounding hodograph structure appears most favorable for low-level rotation/tornado potential east of a weak surface low. ...KS/MO/OK this evening... Redevelopment of severe storms appears probable late this afternoon/early evening in the vicinity of an outflow boundary that continues to slow its southward motion across northern portions of KS/MO. Strong/locally extreme MLCAPE is anticipated near/south of this boundary with substantial shear in the cloud-bearing layer. Storms that develop will likely initially possess supercell characteristics with severe hail (possibly significant) and wind, with eventual upscale growth into one or two MCSs capable of potentially significant severe gusts. The Enhanced Risk area has been reoriented based on expected outflow boundary location later this afternoon and a consensus of 12z CAM guidance/HREF ensemble max probabilities. ...IN/OH into New England... A surface quasistationary front currently extends from northern IN into NY and New England. Substantial heating is underway east of the front, which should allow for destabilization and scattered afternoon thunderstorm development. This area lies along the southern fringe of stronger west/southwesterly flow aloft, with 25-35 knots of deep-layer shear. This may be sufficient for a few strong storms later today capable of gusty/damaging winds. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Wed Jul 12 2023 Valid 122000Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN ILLINOIS/FAR NORTHWESTERN INDIANA...AND PARTS OF EASTERN KANSAS INTO MISSOURI... ...SUMMARY... Severe thunderstorms remain possible across much of Missouri, Illinois, and adjacent portions of the central Plains and Midwest this afternoon through tonight. A few tornadoes should occur this afternoon and evening across parts of northern Illinois into far northwestern Indiana, with a strong tornado possible. Otherwise, damaging winds and large hail should occur with intense thunderstorms that develop, with some potential for significant (75+ mph) severe winds and very large hail across parts of Missouri and Kansas. ...20Z Update... Primary change with this update was to introduce higher tornado probabilities in a narrow corridor across northern IL and far northwestern IN, including Chicago. Recent VWPs from KLOT show impressive low-level shear (0-1 km 35-40+ kt) and enlarged/curved low-level hodographs associated with a focused low-level jet. In the wake of a remnant MCS and lessening precipitation shield, it appears increasingly likely based on recent visible satellite imagery and surface observations that sufficient destabilization to support surface-based convection will occur across this region over the next few hours. Given the very favorable low-level and deep-layer shear available, concern has increased that any supercell which forms in this environment will be capable of producing a tornado. Some potential will exist for a strong tornado as effective SRH strengthens to around 250-350 m2/s2 along/near the developing warm front. The Slight Risk has also been expanded northward in southern Lower MI to account for a small bowing cluster which may develop. No changes have been made to the Enhanced Risk across parts of eastern KS into MO. 18Z sounding from TOP showed warm low/mid-level temperatures and a cap which should continue to inhibit robust convection for at least a couple more hours. Still, intense thunderstorm development is expected later this evening in tandem with a modestly strengthening low-level jet. ..Gleason.. 07/12/2023 .PREV DISCUSSION... /ISSUED 1140 AM CDT Wed Jul 12 2023/ ...Northern IL/southern WI east to northwest OH/southern lower MI... Current MCS continues a general weakening trend based on IR cloud tops, radar trends and recent reports. Air mass recovery in the wake of the morning convection currently appears plausible, aided by a modestly enhanced low-level jet later this afternoon and evening. Steepening mid-level lapse rates will contribute to moderate/pockets of strong MLCAPE this afternoon, and coupled with 40-50 kts of deep-layer shear would result in a favorable parameter space for supercell development by late afternoon/early evening with all severe hazards possible. Will introduce a small 5 percent tornado probability area across this region, where forecast sounding hodograph structure appears most favorable for low-level rotation/tornado potential east of a weak surface low. ...KS/MO/OK this evening... Redevelopment of severe storms appears probable late this afternoon/early evening in the vicinity of an outflow boundary that continues to slow its southward motion across northern portions of KS/MO. Strong/locally extreme MLCAPE is anticipated near/south of this boundary with substantial shear in the cloud-bearing layer. Storms that develop will likely initially possess supercell characteristics with severe hail (possibly significant) and wind, with eventual upscale growth into one or two MCSs capable of potentially significant severe gusts. The Enhanced Risk area has been reoriented based on expected outflow boundary location later this afternoon and a consensus of 12z CAM guidance/HREF ensemble max probabilities. ...IN/OH into New England... A surface quasistationary front currently extends from northern IN into NY and New England. Substantial heating is underway east of the front, which should allow for destabilization and scattered afternoon thunderstorm development. This area lies along the southern fringe of stronger west/southwesterly flow aloft, with 25-35 knots of deep-layer shear. This may be sufficient for a few strong storms later today capable of gusty/damaging winds. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0125 PM CDT Wed Jul 12 2023 Valid 131200Z - 141200Z Minor refinements were made to the elevated area across parts of northwest Arizona into far southeast Nevada, based on the latest guidance. Otherwise, the previous forecast remains on track. See the discussion below for more details. ..Karstens.. 07/12/2023 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Jul 12 2023/ ...Synopsis... The Southwest mid-level high will increase amplitude and re-center itself on Thursday across Arizona with much warmer temperatures and gradual drying of the mid-level moisture plume. Winds will generally be below Elevated or Critical thresholds with a few localized breezes and Elevated areas possible. HREF ensemble guidance does include a better chance for more widespread sustained Elevated fire weather conditions across the Arizona/Utah border. Within this region, afternoon relative humidity reductions to 10-15 percent and sustained winds around 15 mph will be possible. An Elevated delineation was added with this outlook to cover this risk. ...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 Wed Jul 12 2023 Valid 131200Z - 141200Z Minor refinements were made to the elevated area across parts of northwest Arizona into far southeast Nevada, based on the latest guidance. Otherwise, the previous forecast remains on track. See the discussion below for more details. ..Karstens.. 07/12/2023 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Jul 12 2023/ ...Synopsis... The Southwest mid-level high will increase amplitude and re-center itself on Thursday across Arizona with much warmer temperatures and gradual drying of the mid-level moisture plume. Winds will generally be below Elevated or Critical thresholds with a few localized breezes and Elevated areas possible. HREF ensemble guidance does include a better chance for more widespread sustained Elevated fire weather conditions across the Arizona/Utah border. Within this region, afternoon relative humidity reductions to 10-15 percent and sustained winds around 15 mph will be possible. An Elevated delineation was added with this outlook to cover this risk. ...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 12 2023 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY INTO THE NORTHEAST...AND PORTIONS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered severe thunderstorms capable of producing damaging winds, large hail, and perhaps a tornado or two appear possible Thursday across parts of the Ohio Valley into the Northeast, and portions of the southern/central Plains. Isolated very large hail may occur across parts of the central Plains. ...Ohio Valley into the Northeast... A large, closed upper low will persist over the Hudson Bay vicinity on Thursday. Multiple embedded mid-level perturbations, some convectively augmented, should rotate through the base of the upper trough/low across parts of the OH Valley, Mid-Atlantic, and Northeast through the period. A surface low should track from the Lower Great Lakes into southern Quebec by Thursday afternoon, with a weak trailing cold front extending southwestward from the low across western NY into the OH Valley. Scattered to numerous thunderstorms are expected to develop with daytime heating along/ahead of the front. Moderate buoyancy coupled with sufficient deep-layer shear should foster a mix of supercells and multicell clusters capable of producing both large hail and damaging winds as they spread eastward through Thursday evening. A 25-35 kt south-southwesterly low-level jet should generate enough low-level shear to support some threat for a tornado or two with any supercell that can be sustained. Based on latest guidance trends, have expanded the Slight Risk to include more of the OH Valley into the Mid-Atlantic and Northeast. ...Southern/Central Plains... Within a modest low-level upslope flow regime, robust thunderstorms will likely develop by Thursday afternoon along/east of a surface lee trough/stalled front across parts of the southern/central High Plains. Moderate to strong instability is forecast to develop to the east of this surface boundary from parts of southwestern SD into western/central NE, eastern CO, and western KS. Enhanced mid-level west-northwesterly winds, weaker with southward extent into the southern High Plains, should foster 35-50+ kt of deep-layer shear. Although large-scale ascent should remain weak, multiple supercells should develop across this area and spread generally southeastward through Thursday evening. Steep mid-level lapse rates, strong buoyancy, and long/generally straight hodographs at mid/upper levels will support a threat for large to very large hail with any supercell that develops. Some clustering may eventually occur with a greater threat for severe/damaging winds as a low-level jet modestly strengthens. But, details in convective evolution and possible upscale growth into an MCS Thursday evening/night across the southern/central Plains still remain quite uncertain. ...Northern Plains into the Upper Midwest... Initially high-based convection may develop Thursday afternoon across parts of the northern Plains. With a well-mixed boundary layer and steep low/mid-level lapse rates expected, isolated strong to severe wind gusts should be the main threat with this activity. Additional strong to severe thunderstorms may form and spread southeastward across parts of the Dakotas into the Upper Midwest through the day in a persistent northwesterly flow regime aloft. Deep-layer shear across these regions generally appears strong enough for supercells. However, nebulous forcing lends low confidence in pinpointing where a greater concentration of supercells and/or small bowing clusters capable of producing isolated severe hail/wind gusts may develop Thursday afternoon/evening. Have therefore expanded the Marginal Risk across parts of the northern Plains and Upper Midwest to encompass a wide range of possible convective solutions shown by various guidance. ..Gleason.. 07/12/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Wed Jul 12 2023 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY INTO THE NORTHEAST...AND PORTIONS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered severe thunderstorms capable of producing damaging winds, large hail, and perhaps a tornado or two appear possible Thursday across parts of the Ohio Valley into the Northeast, and portions of the southern/central Plains. Isolated very large hail may occur across parts of the central Plains. ...Ohio Valley into the Northeast... A large, closed upper low will persist over the Hudson Bay vicinity on Thursday. Multiple embedded mid-level perturbations, some convectively augmented, should rotate through the base of the upper trough/low across parts of the OH Valley, Mid-Atlantic, and Northeast through the period. A surface low should track from the Lower Great Lakes into southern Quebec by Thursday afternoon, with a weak trailing cold front extending southwestward from the low across western NY into the OH Valley. Scattered to numerous thunderstorms are expected to develop with daytime heating along/ahead of the front. Moderate buoyancy coupled with sufficient deep-layer shear should foster a mix of supercells and multicell clusters capable of producing both large hail and damaging winds as they spread eastward through Thursday evening. A 25-35 kt south-southwesterly low-level jet should generate enough low-level shear to support some threat for a tornado or two with any supercell that can be sustained. Based on latest guidance trends, have expanded the Slight Risk to include more of the OH Valley into the Mid-Atlantic and Northeast. ...Southern/Central Plains... Within a modest low-level upslope flow regime, robust thunderstorms will likely develop by Thursday afternoon along/east of a surface lee trough/stalled front across parts of the southern/central High Plains. Moderate to strong instability is forecast to develop to the east of this surface boundary from parts of southwestern SD into western/central NE, eastern CO, and western KS. Enhanced mid-level west-northwesterly winds, weaker with southward extent into the southern High Plains, should foster 35-50+ kt of deep-layer shear. Although large-scale ascent should remain weak, multiple supercells should develop across this area and spread generally southeastward through Thursday evening. Steep mid-level lapse rates, strong buoyancy, and long/generally straight hodographs at mid/upper levels will support a threat for large to very large hail with any supercell that develops. Some clustering may eventually occur with a greater threat for severe/damaging winds as a low-level jet modestly strengthens. But, details in convective evolution and possible upscale growth into an MCS Thursday evening/night across the southern/central Plains still remain quite uncertain. ...Northern Plains into the Upper Midwest... Initially high-based convection may develop Thursday afternoon across parts of the northern Plains. With a well-mixed boundary layer and steep low/mid-level lapse rates expected, isolated strong to severe wind gusts should be the main threat with this activity. Additional strong to severe thunderstorms may form and spread southeastward across parts of the Dakotas into the Upper Midwest through the day in a persistent northwesterly flow regime aloft. Deep-layer shear across these regions generally appears strong enough for supercells. However, nebulous forcing lends low confidence in pinpointing where a greater concentration of supercells and/or small bowing clusters capable of producing isolated severe hail/wind gusts may develop Thursday afternoon/evening. Have therefore expanded the Marginal Risk across parts of the northern Plains and Upper Midwest to encompass a wide range of possible convective solutions shown by various guidance. ..Gleason.. 07/12/2023 Read more

No Mesoscale Discussions are in effect as of Tue Jul 11 21:35:11 UTC 2023.

WW 0474 Status Updates
STATUS FOR WATCH 0474 HAS NOT BEEN ISSUED YET Read more

WW 474 SEVERE TSTM ND SD WY 112040Z - 120300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 474 NWS Storm Prediction Center Norman OK 240 PM MDT Tue Jul 11 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western North Dakota Western South Dakota Northeast Wyoming * Effective this Tuesday afternoon and evening from 240 PM until 900 PM MDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible A tornado or two possible SUMMARY...Thunderstorm coverage is expected to increase this afternoon and evening as the airmass across the western Dakotas and northeast Wyoming continues to destabilize. Moderate buoyancy and strong vertical shear is in place, with some supercells anticipated. Large to very large hail and damaging gusts are the primary severe risks, but a tornado or two is possible as well. The severe thunderstorm watch area is approximately along and 65 statute miles east and west of a line from 60 miles south southwest of Rapid City SD to 50 miles north of Dickinson ND. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 473... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28030. ...Mosier Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Tue Jul 11 2023 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE MIDWEST... ...SUMMARY... Supercells capable of large to very large hail are possible this afternoon and evening from eastern Montana and western South Dakota into Nebraska. One or more convective lines may evolve late this evening and overnight from central Nebraska into Iowa. Severe wind gusts may occur with this convection. ...20Z Update... The Slight Risk area has been expanded to include more of northeastern MT, western ND, and northwestern SD. Multiple supercells capable of producing large to very large hail should spread east-southeastward across this area through the rest of the afternoon and evening. See Mesoscale Discussion 1498 for more details on the short-term severe threat across this region. Otherwise, minimal changes have been made to the ongoing forecast. Additional convection should eventually develop across parts of NE along/near a front as low-level warm advection gradually increases later this evening. This activity may initially pose a threat for large hail. But, quick upscale growth into an MCS should occur, with a greater threat for severe/damaging winds through the overnight hours across eastern NE into IA. Reference Mesoscale Discussion 1499 for additional information regarding thunderstorms which have recently developed across parts of northern IL and far northwestern IN along a weak front. Isolated strong to severe wind gusts should be the main threat with this activity. ..Gleason.. 07/11/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Tue Jul 11 2023/ ...Eastern MT into SD/NE... Early morning surface analysis places a lee trough across eastern MT to weak low over the northwest NE. Airmass in the vicinity of the lee trough is currently characterized by mid 50s to low 60s dewpoints. Modest mid-level warm advection is fostering widespread cloud cover to the east of the lee troughing across far eastern MT and the Dakotas. This area of cloud cover is forecast to shift eastward over time, allowing for daytime heating to destabilize the air mass. Low-level convergence along the lee trough will be augmented by increasing large-scale forcing as the shortwave trough currently over western MT moves eastward into the region. This combination of air mass destabilization and forcing for ascent is expected to foster thunderstorm development across western MT during the afternoon. Low 60s afternoon dewpoints and temperatures in the 80s beneath steep mid-level lapse rates will support moderate to strong buoyancy, with MLCAPE from 1500 to 2500 J/kg. Enhanced mid-level flow will extend across the region as well, supporting long hodographs and 50+ kt of 0-6 km vertical shear. These environmental conditions will result in an initially supercellular mode, with large to very large hail possible for both left and right splits. High cloud bases suggest strong downbursts are possible as well. Evolution into one or more bowing segments is anticipated after a few hours, with these segments progressing eastward into southwest ND and western SD during the evening, and eventually into parts of NE. Severe threat will continue with these bowing segments, with damaging gusts as the primary risk. ...Central SD/NE into IA... Early morning surface analysis places a cold front from southern IA westward across central NE, linking up with lee troughing across eastern MT via a weak low over the northwest NE Panhandle. Elevated showers and thunderstorm are currently ongoing north of the front across central SD and central NE, with outflow from these storms now emerging across north-central NE. A trend towards more surface-based activity is possible as this outflow continues southward/southeastward as well as with the more southerly storm across central NE. There is also the chance for more in-situ development along the front later this afternoon if skies clear. Main uncertainty is whether or not the air mass sufficiently destabilizes given the current cloudiness and relatively warm mid-levels. As such, a conditional threat for severe thunderstorm is anticipated throughout the afternoon and into the evening, with strong shear likely supporting supercells capable of large to very large hail and damaging gusts. Later this evening, whatever evolves out of the upstream activity across eastern MT and NE Panhandle will likely progress into the region, supporting the potential for damaging gusts and isolated hail throughout the night. Some significant gusts are possible, depending on how organized the system is as it moves into central NE. Even at this shorter range, guidance remains varied on the preferred corridor for this potential MCS, limiting the confidence needed to introduce higher wind probabilities with this outlook. ...North TX into southern MS/AL... MCS that moved across OK last night has weakened considerably, but a well-developed MCV in it wake. This MCV is forecast to drift southeastward throughout the day, with thunderstorms likely in its vicinity as well as along the leading edge of the southeastward-progressing outflow. Winds aloft are weak, which should keep the overall severity limited, with a risk of locally damaging wind gusts in the stronger cells. Read more

WW 0473 Status Updates
STATUS FOR WATCH 0473 HAS NOT BEEN ISSUED YET Read more

WW 473 SEVERE TSTM MT 111955Z - 120300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 473 NWS Storm Prediction Center Norman OK 155 PM MDT Tue Jul 11 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Montana * Effective this Tuesday afternoon and evening from 155 PM until 900 PM MDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Thunderstorm coverage is expected to gradually increase as the airmass continues to destabilize this afternoon. Moderate buoyancy and strong shear is forecast to support supercell capable of large to very large hail and damaging wind gusts. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 15 miles north northwest of Glasgow MT to 25 miles west southwest of Broadus MT. 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28030. ...Mosier Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0134 PM CDT Tue Jul 11 2023 Valid 121200Z - 131200Z An area delineating potential for isolated dry thunderstorms was added to portions of south-central Colorado and north-central New Mexico. Thunderstorms should develop over the region during the afternoon hours and spread east, with the highlighted area confined based on fuels (ERC > 80th percentile). In addition, a slight uptick in the potential for at least locally elevated fire-weather conditions across southern Nevada and vicinity is noted in the latest guidance. Given relatively weak flow aloft, confidence remains too low to introduce any highlights at this time, but highlights may be needed in later outlooks should this trend continue. ..Karstens.. 07/11/2023 .PREV DISCUSSION... /ISSUED 1253 AM CDT Tue Jul 11 2023/ ...Synopsis... High pressure will continue to be the dominant feature across the Western US on Wednesday, keeping primarily light winds where fuels are the driest. A few localized breezes may produce briefly Elevated fire weather but confidence in any one corridor is low. Across the northern periphery of the ridge, increased westerly flow will be possible across southern Wyoming. Conditions will be dry but fuels remain largely unreceptive to fire spread across this region, precluding the need to include any areas at this time. ...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 11 2023 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Severe thunderstorms will be possible across much of Missouri, Illinois, and adjacent portions of the central Plains and Midwest on Wednesday. Damaging winds and large hail should be the main threats, with some potential for significant (75+ mph) severe winds across parts of Missouri and vicinity. ...Synopsis... A closed upper low will remain centered over Hudson Bay and vicinity on Wednesday, while upper ridging persists over the Southwest. Between these two features, a belt of enhanced mid-level west-northwesterly flow will be present over much of the northern Plains into the Upper Midwest and mid/upper MS Valley. ...Central Plains into the Mid Mississippi Valley and Midwest... Although details remain uncertain, one or more thunderstorm clusters will likely be ongoing at the start of the period Wednesday morning across parts of IA into northern MO. An isolated threat for mainly damaging winds may continue through the morning as this activity spreads eastward across the Midwest. But, most guidance shows a general weakening trend with the morning MCS as it generally outpaces available instability with eastward extent. In the wake of this morning convection, strong daytime heating will encourage the development of moderate to strong instability along a convectively reinforced boundary that should extend across KS into MO and perhaps parts of IL. Robust convection will likely form along and south of this boundary Wednesday afternoon/evening as a shortwave trough and associated mid/upper-level jet moves eastward from the northern/central Plains over the Upper Midwest and mid/upper MS Valley. With deep-layer shear forecast to strengthen through the day with the approach of the mid/upper-level jet, initial development may be supercellular and pose a threat for large to very large hail in addition to damaging downdraft winds. This appears most probable across parts of eastern KS into western/central MO. With time, clustering/upscale growth and perhaps an intense MCS will probably occur across parts of MO and vicinity Wednesday evening as a southwesterly low-level jet modestly strengthens. Where this MCS/cluster will develop and move remains rather uncertain. But, strong buoyancy and steepened low/mid-level lapse rates should support a threat for scattered severe/damaging winds and perhaps isolated gusts of 75+ mph. Confidence in a more concentrated corridor of damaging winds remains too uncertain to include greater severe wind probabilities at this time. ...Great Lakes/Northeast... The glancing influence of a shortwave trough moving northeastward across Quebec and the Northeast should encourage at least isolated thunderstorm development along a weak cold front from parts of the Great Lakes region into New England. Weak to locally moderate instability and modest deep-layer shear should support some threat for damaging winds with the strongest cells and small clusters that develop Wednesday afternoon and early evening. ..Gleason.. 07/11/2023 Read more

MD 1488 CONCERNING SEVERE THUNDERSTORM WATCH 468... FOR PARTS OF SOUTHWESTERN NEBRASKA...EASTERN COLORADO...WESTERN KANSAS AND THE TEXAS/OKLAHOMA PANHANDLES
Mesoscale Discussion 1488 NWS Storm Prediction Center Norman OK 0459 PM CDT Mon Jul 10 2023 Areas affected...parts of southwestern Nebraska...eastern Colorado...western Kansas and the Texas/Oklahoma Panhandles Concerning...Severe Thunderstorm Watch 468... Valid 102159Z - 110000Z The severe weather threat for Severe Thunderstorm Watch 468 continues. SUMMARY...Widely scattered strong to severe thunderstorm development remains possible into the 6-8 PM CDT time frame, with at least one upscale growing cluster possibly beginning to evolve across far southwestern Kansas into the Oklahoma and Texas Panhandle vicinity. Areas to the south of WW 468 are still being monitored for an additional severe weather watch. DISCUSSION...Widely scattered strong thunderstorm development continues to propagate slowly eastward into lee surface troughing, where a more moist boundary-layer has become characterized by large CAPE, but remains fairly strongly capped based on latest mesoanalysis. Storm motions are slow due to weak deep-layer mean flow on the order of 15 kts or less, but, due to veering profiles with height, deep-layer shear is strong and supportive of organized convection, including supercells. Highest potential for continuing storm development into 23-01Z may remain focused roughly northwest through north of the Goodland vicinity, where inhibition appears weakest, and north through east of the Raton Mesa vicinity into the Texas/Oklahoma Panhandle vicinity, where activity may be aided by forcing associated with a perturbation rounding the northeast periphery of the subtropical high. The southern storm development may begin to focus and organize along a zone of stronger differential surface heating extending northwest through southeast across the Panhandle vicinity. ..Kerr.. 07/10/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...DDC...GLD...AMA...PUB...ABQ... LAT...LON 39750160 40540104 39769982 37390109 35970039 35220176 35200332 35790330 36390272 37320275 37970266 39280224 39750160 Read more

WW 0468 Status Updates
STATUS REPORT ON WW 468 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SUPINIE..07/10/23 ATTN...WFO...PUB...GLD...BOU...DDC... STATUS REPORT FOR WS 468 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC009-011-017-025-061-063-073-075-089-095-099-115-121-125- 102240- CO . COLORADO COUNTIES INCLUDED ARE BACA BENT CHEYENNE CROWLEY KIOWA KIT CARSON LINCOLN LOGAN OTERO PHILLIPS PROWERS SEDGWICK WASHINGTON YUMA KSC023-039-063-065-067-071-075-093-109-129-137-153-179-181-187- 189-193-199-203-102240- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GOVE GRAHAM GRANT GREELEY HAMILTON KEARNY LOGAN MORTON NORTON RAWLINS SHERIDAN SHERMAN STANTON STEVENS THOMAS WALLACE WICHITA Read more

WW 468 SEVERE TSTM CO KS NE 101935Z - 110100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 468 NWS Storm Prediction Center Norman OK 135 PM MDT Mon Jul 10 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Colorado Western Kansas Far Southwest Nebraska * Effective this Monday afternoon and evening from 135 PM until 700 PM MDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph likely Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible SUMMARY...Thunderstorms are expected to increase in intensity and coverage across the region this afternoon. The environment is becoming increasingly unstable, with strong shear present as well. These environmental conditions will support storms capable of large to very large hail and strong downburst, with gust of 75 mph possible. The severe thunderstorm watch area is approximately along and 70 statute miles east and west of a line from 55 miles west northwest of Mccook NE to 50 miles south southeast of Lamar CO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24025. ...Mosier Read more