Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sat Aug 17 2019 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST SD...NORTHWEST IA...SOUTHWEST MN... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE NORTHEAST... ...SUMMARY... Scattered severe thunderstorms with damaging winds and large hail as the primary threats are expected across a large portion of the northern to central Great Plains into the Midwest, generally during the late afternoon into tonight. Damaging winds are also possible into early evening in parts of the Northeast States. ...Northern Great Plains/Upper Midwest... A broad positive-tilt shortwave trough will advance east across the southern Prairie Provinces and MT to ND through tonight. A surface front well in advance of this wave extends from the Red River Valley southwest towards the Black Hills and should remain quasi-stationary before accelerating south/east tonight. The bulk of stronger mid-level west-southwesterlies accompanying the wave will remain confined to the cool side of the front, while a separate belt of enhanced westerlies is confined south across NE. In addition, the northern periphery of steeper mid-level lapse rates from an elevated mixed-layer will probably only overlap the SD portion of the front. Low to mid 60s F surface dew points are expected along the front and should support moderate buoyancy with MLCAPE around 1500-2500 J/kg. Owing to a lack of stronger capping, at least scattered thunderstorms will develop in the late afternoon. A few transient supercells should develop initially, but hodographs do not appear particularly elongated or enlarged given modest low-level winds and weakness aloft in the split flow regime. Given the frontal forcing and predominance of outflow consolidation, broader clusters fusing into one or more lines are expected with eastern extent tonight. Some risk for damaging winds will probably continue across southern MN and northern IA along the northern extent of the larger buoyancy plume. ...Central Great Plains... High-based convection that develops off the Front Range this afternoon should impinge on the recovering moist sector near the CO/KS/NE border towards early evening. On the southern periphery of a belt of enhanced mid-level westerlies centered from southern WY across NE amid a very steep lapse rate environment, a swath of severe wind gusts will be possible into north-central KS tonight. ...Mid-MS Valley to IN vicinity... An MCV is centered near the MO/IA/IL border area and should drift east. Several CAMs indicate redevelopment of scattered storms ahead of this feature. This will be highly dependent on more robust destabilization occurring in the wake of a leading MCS in IN. At least a conditional threat for damaging winds and severe hail exists, mainly during the evening. Warm-advection storms overnight may also pose an isolated severe risk. ...Northeast... A low-amplitude shortwave impulse over southern Ontario should slowly move across the Saint Lawrence Valley. Scattered convection is ongoing in association with this wave and will likely persist through the afternoon as further surface-based destabilization occurs downstream. Weak low-level winds and modest mid-level lapse rates will be limiting factors. Most of the stronger speed shear should be confined to the upper portion of the buoyancy profile. Setup should foster a risk of isolated marginally severe hail and scattered damaging winds. ..Grams.. 08/17/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Sat Aug 17 2019 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS REGION... ...SUMMARY... The greatest threat for severe storms appears to be over parts of the northern and central Plains into the upper Midwest late this afternoon into tonight. ...Synopsis... In mid/upper levels, a highly amplified and blocky pattern inhabits North America's neighborhood in the Northern Hemisphere. A large, complex cyclone will remain anchored over the north-central Pacific, with sharp ridging to its north through east, from the Bering Sea to waters west of both CA and Baja. Broadly cyclonic mean flow will persist over much of Canada and the northern half of the CONUS, much of it accompanied by seasonally cold mid/upper-level temperatures. The most influential shortwave feature appears to be the trough now moving eastward out of the northern Rockies region, and forecast to amplify as it crosses MT and the Dakotas through the period. By 12Z, this perturbation should reach southeastern MB, eastern ND and central/eastern SD. Meanwhile, convectively generated/enhanced vorticity maxima from prior activity will aid convective potential on the mesoscale across portions of the marginal-risk area from IN-NY. At the surface, the 11Z analysis showed a surface low over extreme northern Lower MI with cold front southwestward across northern IL, becoming quasistationary and somewhat diffused by convective activity over southern IA and southern NE. Baroclinicity was stronger on an outflow arc extending from eastern MO across the eastern KS/OK border region to west-central KS. The latter boundary should weaken from west to east through the day, with some northeastward retreat possible, while the frontal zone to its north moves little. Meanwhile, a better-defined cold front was drawn from southern MB across east-central ND and northwestern SD, to a low over northeastern WY. This front should move eastward/southeastward across the remainder of the northern Plains through the period. By 12Z the cold front should reach eastern MN, western/central IA, southeastern NE, and northeastern CO. ...North-central Plains, upper Midwest... Scattered thunderstorms should develop over western parts of the north-central Plains this afternoon, predominantly along the cold front and over higher terrain in and near the Black Hills and Bighorns, offering the potential for severe hail/gusts. Supercells are possible relatively early in the convective cycle. Then the potential exists for some of the western SD/frontal activity to evolve upscale toward a more wind-dominant severe risk, perhaps aided by additional convective development to its east. Being fairly well-removed from the ongoing extensive clouds/precip in the eastern KS/MO region, areas of strong heating are expected in the prefrontal warm sector. This, combined with 60s F surface dew points and steep low/middle-level lapse rates, should render areas of 2000-3500 J/kg late-afternoon/preconvective MLCAPE in central/ eastern SD and much of NE, decreasing westward toward the higher terrain as moisture diminishes (but still should be sufficient to support convection). Vertical shear should strengthen through the afternoon and evening in the warm sector, with 40-55-kt effective- shear magnitudes supporting supercell potential before upscale growth occurs. The threat accordingly should transition from hail to wind with time into the overnight period. ...IA, eastern NE, portions of KS, northern MO... Additional scattered to numerous thunderstorms may form farther south tonight over parts of the eastern NE/IA/northern MO area in a zone of strong low-level warm advection and moisture transport, with severe/significant hail potential. This regime is a good deal more uncertain in how it may develop and evolve, including how much influence may persist from High Plains activity persisting into the region vs. in situ development with the warm-advection/LLJ corridor. The extensive area of antecedent convection over KS/MO -- and related airmass effects on timing/extent of recovery farther north this afternoon and evening -- yield the bulk of uncertainty in this forecast. The severe that occurred late over KS/MO during the past overnight period required 12-18 hours of postconvective recovery following extensive convection to the south. Loosely similarly, a delayed onset of convective/severe potential into the evening/overnight hours is probable across the outlook area again this day-1 period. Two main differences will be: 1. Somewhat weaker but still adequate low-level moisture/theta-e, and 2. Stronger but still peripheral mid/upper-level influences southeast of the pronounced shortwave trough, in terms of synoptic-scale lift via warm advection and weak DCVA/cooling, and strengthening gradient winds aloft for favorable deep shear. At this time, uncertainty remains too large to increase or areally refine the unconditional severe probabilities. ..Edwards/Marsh.. 08/17/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Sat Aug 17 2019 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS REGION... ...SUMMARY... The greatest threat for severe storms appears to be over parts of the northern and central Plains into the upper Midwest late this afternoon into tonight. ...Synopsis... In mid/upper levels, a highly amplified and blocky pattern inhabits North America's neighborhood in the Northern Hemisphere. A large, complex cyclone will remain anchored over the north-central Pacific, with sharp ridging to its north through east, from the Bering Sea to waters west of both CA and Baja. Broadly cyclonic mean flow will persist over much of Canada and the northern half of the CONUS, much of it accompanied by seasonally cold mid/upper-level temperatures. The most influential shortwave feature appears to be the trough now moving eastward out of the northern Rockies region, and forecast to amplify as it crosses MT and the Dakotas through the period. By 12Z, this perturbation should reach southeastern MB, eastern ND and central/eastern SD. Meanwhile, convectively generated/enhanced vorticity maxima from prior activity will aid convective potential on the mesoscale across portions of the marginal-risk area from IN-NY. At the surface, the 11Z analysis showed a surface low over extreme northern Lower MI with cold front southwestward across northern IL, becoming quasistationary and somewhat diffused by convective activity over southern IA and southern NE. Baroclinicity was stronger on an outflow arc extending from eastern MO across the eastern KS/OK border region to west-central KS. The latter boundary should weaken from west to east through the day, with some northeastward retreat possible, while the frontal zone to its north moves little. Meanwhile, a better-defined cold front was drawn from southern MB across east-central ND and northwestern SD, to a low over northeastern WY. This front should move eastward/southeastward across the remainder of the northern Plains through the period. By 12Z the cold front should reach eastern MN, western/central IA, southeastern NE, and northeastern CO. ...North-central Plains, upper Midwest... Scattered thunderstorms should develop over western parts of the north-central Plains this afternoon, predominantly along the cold front and over higher terrain in and near the Black Hills and Bighorns, offering the potential for severe hail/gusts. Supercells are possible relatively early in the convective cycle. Then the potential exists for some of the western SD/frontal activity to evolve upscale toward a more wind-dominant severe risk, perhaps aided by additional convective development to its east. Being fairly well-removed from the ongoing extensive clouds/precip in the eastern KS/MO region, areas of strong heating are expected in the prefrontal warm sector. This, combined with 60s F surface dew points and steep low/middle-level lapse rates, should render areas of 2000-3500 J/kg late-afternoon/preconvective MLCAPE in central/ eastern SD and much of NE, decreasing westward toward the higher terrain as moisture diminishes (but still should be sufficient to support convection). Vertical shear should strengthen through the afternoon and evening in the warm sector, with 40-55-kt effective- shear magnitudes supporting supercell potential before upscale growth occurs. The threat accordingly should transition from hail to wind with time into the overnight period. ...IA, eastern NE, portions of KS, northern MO... Additional scattered to numerous thunderstorms may form farther south tonight over parts of the eastern NE/IA/northern MO area in a zone of strong low-level warm advection and moisture transport, with severe/significant hail potential. This regime is a good deal more uncertain in how it may develop and evolve, including how much influence may persist from High Plains activity persisting into the region vs. in situ development with the warm-advection/LLJ corridor. The extensive area of antecedent convection over KS/MO -- and related airmass effects on timing/extent of recovery farther north this afternoon and evening -- yield the bulk of uncertainty in this forecast. The severe that occurred late over KS/MO during the past overnight period required 12-18 hours of postconvective recovery following extensive convection to the south. Loosely similarly, a delayed onset of convective/severe potential into the evening/overnight hours is probable across the outlook area again this day-1 period. Two main differences will be: 1. Somewhat weaker but still adequate low-level moisture/theta-e, and 2. Stronger but still peripheral mid/upper-level influences southeast of the pronounced shortwave trough, in terms of synoptic-scale lift via warm advection and weak DCVA/cooling, and strengthening gradient winds aloft for favorable deep shear. At this time, uncertainty remains too large to increase or areally refine the unconditional severe probabilities. ..Edwards/Marsh.. 08/17/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Sat Aug 17 2019 Valid 171300Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS REGION... ...SUMMARY... The greatest threat for severe storms appears to be over parts of the northern and central Plains into the upper Midwest late this afternoon into tonight. ...Synopsis... In mid/upper levels, a highly amplified and blocky pattern inhabits North America's neighborhood in the Northern Hemisphere. A large, complex cyclone will remain anchored over the north-central Pacific, with sharp ridging to its north through east, from the Bering Sea to waters west of both CA and Baja. Broadly cyclonic mean flow will persist over much of Canada and the northern half of the CONUS, much of it accompanied by seasonally cold mid/upper-level temperatures. The most influential shortwave feature appears to be the trough now moving eastward out of the northern Rockies region, and forecast to amplify as it crosses MT and the Dakotas through the period. By 12Z, this perturbation should reach southeastern MB, eastern ND and central/eastern SD. Meanwhile, convectively generated/enhanced vorticity maxima from prior activity will aid convective potential on the mesoscale across portions of the marginal-risk area from IN-NY. At the surface, the 11Z analysis showed a surface low over extreme northern Lower MI with cold front southwestward across northern IL, becoming quasistationary and somewhat diffused by convective activity over southern IA and southern NE. Baroclinicity was stronger on an outflow arc extending from eastern MO across the eastern KS/OK border region to west-central KS. The latter boundary should weaken from west to east through the day, with some northeastward retreat possible, while the frontal zone to its north moves little. Meanwhile, a better-defined cold front was drawn from southern MB across east-central ND and northwestern SD, to a low over northeastern WY. This front should move eastward/southeastward across the remainder of the northern Plains through the period. By 12Z the cold front should reach eastern MN, western/central IA, southeastern NE, and northeastern CO. ...North-central Plains, upper Midwest... Scattered thunderstorms should develop over western parts of the north-central Plains this afternoon, predominantly along the cold front and over higher terrain in and near the Black Hills and Bighorns, offering the potential for severe hail/gusts. Supercells are possible relatively early in the convective cycle. Then the potential exists for some of the western SD/frontal activity to evolve upscale toward a more wind-dominant severe risk, perhaps aided by additional convective development to its east. Being fairly well-removed from the ongoing extensive clouds/precip in the eastern KS/MO region, areas of strong heating are expected in the prefrontal warm sector. This, combined with 60s F surface dew points and steep low/middle-level lapse rates, should render areas of 2000-3500 J/kg late-afternoon/preconvective MLCAPE in central/ eastern SD and much of NE, decreasing westward toward the higher terrain as moisture diminishes (but still should be sufficient to support convection). Vertical shear should strengthen through the afternoon and evening in the warm sector, with 40-55-kt effective- shear magnitudes supporting supercell potential before upscale growth occurs. The threat accordingly should transition from hail to wind with time into the overnight period. ...IA, eastern NE, portions of KS, northern MO... Additional scattered to numerous thunderstorms may form farther south tonight over parts of the eastern NE/IA/northern MO area in a zone of strong low-level warm advection and moisture transport, with severe/significant hail potential. This regime is a good deal more uncertain in how it may develop and evolve, including how much influence may persist from High Plains activity persisting into the region vs. in situ development with the warm-advection/LLJ corridor. The extensive area of antecedent convection over KS/MO -- and related airmass effects on timing/extent of recovery farther north this afternoon and evening -- yield the bulk of uncertainty in this forecast. The severe that occurred late over KS/MO during the past overnight period required 12-18 hours of postconvective recovery following extensive convection to the south. Loosely similarly, a delayed onset of convective/severe potential into the evening/overnight hours is probable across the outlook area again this day-1 period. Two main differences will be: 1. Somewhat weaker but still adequate low-level moisture/theta-e, and 2. Stronger but still peripheral mid/upper-level influences southeast of the pronounced shortwave trough, in terms of synoptic-scale lift via warm advection and weak DCVA/cooling, and strengthening gradient winds aloft for favorable deep shear. At this time, uncertainty remains too large to increase or areally refine the unconditional severe probabilities. ..Edwards/Marsh.. 08/17/2019 Read more

MD 1767 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL AND NORTHERN ILLINOIS AND WESTERN INDIANA
Mesoscale Discussion 1767 NWS Storm Prediction Center Norman OK 0800 AM CDT Sat Aug 17 2019 Areas affected...central and northern Illinois and western Indiana Concerning...Severe potential...Watch unlikely Valid 171300Z - 171500Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorms will continue to move out of Missouri and into central Illinois this morning. Additional thunderstorms will be possible across northern Illinois as well. Hail and gusty winds may be possible with the strongest cores. The area will be monitored for potential watch, but current indications are that the threat should remain sufficiently isolated to not warrant one. DISCUSSION...Long-lived cluster of thunderstorms continues to move east from northern Missouri into central Iowa. Most-unstable CAPE along and ahead of this cluster is around 1000-1500 J/kg; however, deep-layer shear is generally less than 25 knots. Thus, although a severe hail or strong thunderstorm wind gust will be possible with the strongest cores, the threat should remain sufficiently isolated/episodic that a watch is not currently anticipated for this activity. To the north, across northern Illinois, additional thunderstorms may develop within a belt of stronger midlevel flow, likely in response to ageostrophic forcing from the mesoscale convective system to the southwest. The result will be thunderstorms developing in an objectively analyzed environment of most-unstable CAPE around 1000-1500 J/kg and deep-layer shear of 40-50 knots. Although this would normally suggest a threat for organized severe thunderstorms, considerable uncertainty remains regarding convective coverage and longevity. As such, area will continue to be monitored for potential watch, but expectations are that the threat will remain too isolated in nature to warrant watch issuance. ..Marsh/Edwards.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN... LAT...LON 39948994 41609062 42338945 41488669 39198715 38529025 39948994 Read more

WW 0589 Status Updates
STATUS REPORT ON WW 589 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 W EMP TO 35 SSW FNB TO 15 SE IRK. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1766. ..MARSH..08/17/19 ATTN...WFO...TOP...EAX...ICT...DDC...GLD...GID...OAX... STATUS REPORT FOR WS 589 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC003-005-017-031-045-059-085-087-091-103-107-111-121-127-139- 177-197-209-171040- KS . KANSAS COUNTIES INCLUDED ARE ANDERSON ATCHISON CHASE COFFEY DOUGLAS FRANKLIN JACKSON JEFFERSON JOHNSON LEAVENWORTH LINN LYON MIAMI MORRIS OSAGE SHAWNEE WABAUNSEE WYANDOTTE MOC013-021-025-033-037-041-047-049-053-083-089-095-101-107-115- 117-121-159-165-175-177-195-171040- MO . MISSOURI COUNTIES INCLUDED ARE BATES BUCHANAN CALDWELL CARROLL CASS CHARITON CLAY CLINTON COOPER Read more

WW 0589 Status Updates
STATUS REPORT ON WW 589 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 W EMP TO 35 SSW FNB TO 15 SE IRK. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1766. ..MARSH..08/17/19 ATTN...WFO...TOP...EAX...ICT...DDC...GLD...GID...OAX... STATUS REPORT FOR WS 589 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC003-005-017-031-045-059-085-087-091-103-107-111-121-127-139- 177-197-209-171040- KS . KANSAS COUNTIES INCLUDED ARE ANDERSON ATCHISON CHASE COFFEY DOUGLAS FRANKLIN JACKSON JEFFERSON JOHNSON LEAVENWORTH LINN LYON MIAMI MORRIS OSAGE SHAWNEE WABAUNSEE WYANDOTTE MOC013-021-025-033-037-041-047-049-053-083-089-095-101-107-115- 117-121-159-165-175-177-195-171040- MO . MISSOURI COUNTIES INCLUDED ARE BATES BUCHANAN CALDWELL CARROLL CASS CHARITON CLAY CLINTON COOPER Read more

WW 589 SEVERE TSTM KS MO NE 170440Z - 171200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 589 NWS Storm Prediction Center Norman OK 1140 PM CDT Fri Aug 16 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Kansas Western and north-central Missouri Southeast Nebraska * Effective this Friday night and Saturday morning from 1140 PM until 700 AM CDT. * Primary threats include... Scattered large hail likely with isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Initially isolated severe thunderstorms will continue to develop early in the overnight, particularly across the northern half or two-thirds of Kansas. Storms will gradually spread into western/north-central Missouri overnight and possibly southeast Nebraska as well. Large hail will the most common risk. Some potential also exists for damaging winds, particularly if storms merge and grow into a linear complex, which is most likely to occur across eastern Kansas into Missouri. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 75 miles west southwest of Hill City KS to 50 miles east southeast of Chillicothe MO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). 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 600. Mean storm motion vector 27025. ...Guyer Read more

MD 1766 CONCERNING SEVERE THUNDERSTORM WATCH 589... FOR EASTERN KANSAS AND MISSOURI
Mesoscale Discussion 1766 NWS Storm Prediction Center Norman OK 0440 AM CDT Sat Aug 17 2019 Areas affected...eastern Kansas and Missouri Concerning...Severe Thunderstorm Watch 589... Valid 170940Z - 171145Z The severe weather threat for Severe Thunderstorm Watch 589 continues. SUMMARY...Thunderstorm intensity continues to decrease across most of the area, and this trend should continue. The lone exception is a storm moving southeast toward southwest Missouri. Gusty winds and hail will be the main threat with this storm. A new watch is currently not anticipated. DISCUSSION...Widespread thunderstorm activity and effects from what appears to be a large heat burst across south-central Kansas appear to have stabilized much of the airmass across Kansas. The effect of this is an general decrease of thunderstorm intensity. Farther east, across far eastern Kansas and western Missouri, a more favorable thermodynamic environment for thunderstorms remains in place, where most-unstable CAPE values around 2000 J/kg exist. However, the kinematic environment is more hostile to thunderstorm organization with deep-layer shear generally less than 25 knots. The most intense thunderstorm across the central United States is moving across west-cental Missouri, within the aforementioned environment. Given the current thunderstorm organization and favorable thermodynamic environment ahead of the storm, continued gusty winds and hail will be possible with this storm in the short term. However, with time, thunderstorm organization will lessen and therefore the thunderstorm should weaken. In fact, recent radar imagery suggests this may already be underway with indications of a turn to the east occurring. To the northeast, across northeast Missouri, a couple of thunderstorms have briefly intensified within the last hour. The thermodynamic environment here is weaker than farther southwest, but the deep-layer shear is better. Current suggestion is that although a brief severe hail or wind threat may develop with any sustained/intense updraft, the overall threat should remain limited and a new watch will not be needed. ..Marsh.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...SGF...EAX...OAX...TOP...ICT... LAT...LON 38209787 38949791 38979735 40359734 40359688 40529686 40519644 40279647 40249506 40159506 40139462 40049460 40029422 40129418 40119377 40269374 40239332 40069337 40009228 39259233 38689264 38689307 38519307 38529354 38239352 38199406 38049405 38069593 38199596 38159635 38089637 38119718 38179718 38209787 Read more

WW 0589 Status Updates
STATUS REPORT ON WW 589 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 SSW RSL TO 25 NNW RSL TO 45 NNW RSL TO 15 WSW BIE. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1765. ..MARSH..08/17/19 ATTN...WFO...TOP...EAX...ICT...DDC...GLD...GID...OAX... STATUS REPORT FOR WS 589 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC003-005-009-013-017-027-029-031-041-043-045-053-059-061-085- 087-089-091-103-105-107-111-113-115-117-121-123-127-131-139-141- 143-149-157-159-161-167-169-177-197-201-209-170940- KS . KANSAS COUNTIES INCLUDED ARE ANDERSON ATCHISON BARTON BROWN CHASE CLAY CLOUD COFFEY DICKINSON DONIPHAN DOUGLAS ELLSWORTH FRANKLIN GEARY JACKSON JEFFERSON JEWELL JOHNSON LEAVENWORTH LINCOLN LINN LYON MCPHERSON MARION MARSHALL MIAMI MITCHELL MORRIS NEMAHA OSAGE OSBORNE OTTAWA POTTAWATOMIE REPUBLIC RICE RILEY RUSSELL SALINE SHAWNEE WABAUNSEE WASHINGTON WYANDOTTE Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0300 AM CDT Sat Aug 17 2019 Valid 201200Z - 251200Z ...DISCUSSION... Models are in reasonable agreement with the large-scale pattern through Thursday/D6, showing an upper high moving from the Plains westward toward the Four Corners, and a large trough amplification over much of eastern Canada. This trough will bring strengthening northwest flow aloft across the upper MS Valley on Tuesday/D4, and across the Upper Great Lakes on Wednesday/D5. The greatest threat of severe storms will be on Tuesday/D4, potentially the final day of strong to extreme instability for the forecast period. MUCAPE is forecast to range from 3000-5000 J/kg from eastern NE across much of IA, IL, and MO, on the southern fringe of the stronger winds aloft. ECMWF and MREF members generally show severe storm potential within this corridor, beginning late Tuesday/D4 afternoon over NE, and perhaps early in the day over IA, and continuing through the night across MO and IL. Given the glancing/subtle height falls with the upper trough to the north, and the possibility of early storms over IA, will defer possible upgrades to later outlooks. Damaging winds will be the primary concern on Tuesday/D4. For the period Wednesday D5 through Saturday/D8, models show storm chances translating southward across the central and eventually southern Plains as a front shifts south, but instability will be lessening. In addition, winds aloft will remain weak in these areas. As such, only isolated severe is expected during this time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0300 AM CDT Sat Aug 17 2019 Valid 201200Z - 251200Z ...DISCUSSION... Models are in reasonable agreement with the large-scale pattern through Thursday/D6, showing an upper high moving from the Plains westward toward the Four Corners, and a large trough amplification over much of eastern Canada. This trough will bring strengthening northwest flow aloft across the upper MS Valley on Tuesday/D4, and across the Upper Great Lakes on Wednesday/D5. The greatest threat of severe storms will be on Tuesday/D4, potentially the final day of strong to extreme instability for the forecast period. MUCAPE is forecast to range from 3000-5000 J/kg from eastern NE across much of IA, IL, and MO, on the southern fringe of the stronger winds aloft. ECMWF and MREF members generally show severe storm potential within this corridor, beginning late Tuesday/D4 afternoon over NE, and perhaps early in the day over IA, and continuing through the night across MO and IL. Given the glancing/subtle height falls with the upper trough to the north, and the possibility of early storms over IA, will defer possible upgrades to later outlooks. Damaging winds will be the primary concern on Tuesday/D4. For the period Wednesday D5 through Saturday/D8, models show storm chances translating southward across the central and eventually southern Plains as a front shifts south, but instability will be lessening. In addition, winds aloft will remain weak in these areas. As such, only isolated severe is expected during this time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0300 AM CDT Sat Aug 17 2019 Valid 201200Z - 251200Z ...DISCUSSION... Models are in reasonable agreement with the large-scale pattern through Thursday/D6, showing an upper high moving from the Plains westward toward the Four Corners, and a large trough amplification over much of eastern Canada. This trough will bring strengthening northwest flow aloft across the upper MS Valley on Tuesday/D4, and across the Upper Great Lakes on Wednesday/D5. The greatest threat of severe storms will be on Tuesday/D4, potentially the final day of strong to extreme instability for the forecast period. MUCAPE is forecast to range from 3000-5000 J/kg from eastern NE across much of IA, IL, and MO, on the southern fringe of the stronger winds aloft. ECMWF and MREF members generally show severe storm potential within this corridor, beginning late Tuesday/D4 afternoon over NE, and perhaps early in the day over IA, and continuing through the night across MO and IL. Given the glancing/subtle height falls with the upper trough to the north, and the possibility of early storms over IA, will defer possible upgrades to later outlooks. Damaging winds will be the primary concern on Tuesday/D4. For the period Wednesday D5 through Saturday/D8, models show storm chances translating southward across the central and eventually southern Plains as a front shifts south, but instability will be lessening. In addition, winds aloft will remain weak in these areas. As such, only isolated severe is expected during this time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0300 AM CDT Sat Aug 17 2019 Valid 201200Z - 251200Z ...DISCUSSION... Models are in reasonable agreement with the large-scale pattern through Thursday/D6, showing an upper high moving from the Plains westward toward the Four Corners, and a large trough amplification over much of eastern Canada. This trough will bring strengthening northwest flow aloft across the upper MS Valley on Tuesday/D4, and across the Upper Great Lakes on Wednesday/D5. The greatest threat of severe storms will be on Tuesday/D4, potentially the final day of strong to extreme instability for the forecast period. MUCAPE is forecast to range from 3000-5000 J/kg from eastern NE across much of IA, IL, and MO, on the southern fringe of the stronger winds aloft. ECMWF and MREF members generally show severe storm potential within this corridor, beginning late Tuesday/D4 afternoon over NE, and perhaps early in the day over IA, and continuing through the night across MO and IL. Given the glancing/subtle height falls with the upper trough to the north, and the possibility of early storms over IA, will defer possible upgrades to later outlooks. Damaging winds will be the primary concern on Tuesday/D4. For the period Wednesday D5 through Saturday/D8, models show storm chances translating southward across the central and eventually southern Plains as a front shifts south, but instability will be lessening. In addition, winds aloft will remain weak in these areas. As such, only isolated severe is expected during this time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0300 AM CDT Sat Aug 17 2019 Valid 201200Z - 251200Z ...DISCUSSION... Models are in reasonable agreement with the large-scale pattern through Thursday/D6, showing an upper high moving from the Plains westward toward the Four Corners, and a large trough amplification over much of eastern Canada. This trough will bring strengthening northwest flow aloft across the upper MS Valley on Tuesday/D4, and across the Upper Great Lakes on Wednesday/D5. The greatest threat of severe storms will be on Tuesday/D4, potentially the final day of strong to extreme instability for the forecast period. MUCAPE is forecast to range from 3000-5000 J/kg from eastern NE across much of IA, IL, and MO, on the southern fringe of the stronger winds aloft. ECMWF and MREF members generally show severe storm potential within this corridor, beginning late Tuesday/D4 afternoon over NE, and perhaps early in the day over IA, and continuing through the night across MO and IL. Given the glancing/subtle height falls with the upper trough to the north, and the possibility of early storms over IA, will defer possible upgrades to later outlooks. Damaging winds will be the primary concern on Tuesday/D4. For the period Wednesday D5 through Saturday/D8, models show storm chances translating southward across the central and eventually southern Plains as a front shifts south, but instability will be lessening. In addition, winds aloft will remain weak in these areas. As such, only isolated severe is expected during this time frame. Read more

MD 1765 CONCERNING SEVERE THUNDERSTORM WATCH 589... FOR KANSAS AND NORTHWEST MISSOURI
Mesoscale Discussion 1765 NWS Storm Prediction Center Norman OK 0240 AM CDT Sat Aug 17 2019 Areas affected...kansas and northwest Missouri Concerning...Severe Thunderstorm Watch 589... Valid 170740Z - 170915Z The severe weather threat for Severe Thunderstorm Watch 589 continues. SUMMARY...Thunderstorms continue across much of Kansas and are spreading into northwest Missouri. Large hail and a gusty thunderstorm winds are the main threats. DISCUSSION...Multiple clusters of thunderstorms persist this morning across much of northern Kansas and into northwest Missouri. The mesoscale airmass across the region remains supportive of severe thunderstorms -- namely large hail and gusty thunderstorm winds -- as evidenced by most-unstable CAPE values in excess of 3000 J/kg and deep layer shear between 30-50 knots. One negative to a more widespread severe episode is the number of ongoing/developing storms tapping into this airmass, which should locally reduce the overall instability. The result should be a gradual weakening of overall thunderstorm intensity and a transition to a more episodic severe threat, especially across north-central Kansas where previous thunderstorm duration and ongoing thunderstorm coverage is greatest. Farther east, where the airmass is less contaminated by early convection, a more sustained severe potential will exist initially, before a gradual weakening trend takes hold. Large hail and damaging winds will be the primary severe threats. ..Marsh.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...SGF...EAX...OAX...TOP...ICT...GID...DDC... GLD... LAT...LON 38240156 38680158 38700146 39110151 39120135 39530135 39579959 40029960 39989824 40339828 40369692 40519690 40509647 40289647 40259503 40149502 40119462 40019464 40019426 40139421 40119378 40229375 40249339 40049334 40039232 39269230 39229242 38999258 38939249 38699262 38689304 38509306 38529348 38219356 38209406 38019407 38059599 38159598 38179631 38069634 38099715 38209716 38179849 38269854 38259901 38339904 38349963 38259959 38240156 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sat Aug 17 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis and Discussion... A negative-tilt shortwave trough will quickly move from southern Ontario across Quebec, followed closely by another area of cyclonic flow aloft amplifying over SK and MB. The southern periphery of the stronger flow aloft will affect parts of the Dakotas and MN late in the day when subtle height falls will commence. At the surface, a wind shift/weak front will approach the central Dakotas by late afternoon with a plume of mid to upper 60s F dewpoints spreading northward out of the central Plains ahead of the front. Strong instability will develop across this region, but capping will mitigate storm formation during much of the day. Isolated storms are possible along the front by late afternoon or early evening, aided by heating and modest low-level warm advection with 20 kt 850 mb flow. Additional nocturnal storms, likely elevated, are possible into western MN and southward along the MO River in the warm advection regime, and where instability will remain strong. Hail appears to be the main threat with this activity. Models suggest an increase in storm coverage, possibly an MCS, after 12Z Tuesday which is later than previously forecast. As such, have reduced severe probabilities for expected isolated coverage on Monday. Elsewhere, scattered storms are possible from the mid MS Valley across the OH Valley, where instability will remain strong but with rising heights aloft and weak shear. ..Jewell.. 08/17/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sat Aug 17 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis and Discussion... A negative-tilt shortwave trough will quickly move from southern Ontario across Quebec, followed closely by another area of cyclonic flow aloft amplifying over SK and MB. The southern periphery of the stronger flow aloft will affect parts of the Dakotas and MN late in the day when subtle height falls will commence. At the surface, a wind shift/weak front will approach the central Dakotas by late afternoon with a plume of mid to upper 60s F dewpoints spreading northward out of the central Plains ahead of the front. Strong instability will develop across this region, but capping will mitigate storm formation during much of the day. Isolated storms are possible along the front by late afternoon or early evening, aided by heating and modest low-level warm advection with 20 kt 850 mb flow. Additional nocturnal storms, likely elevated, are possible into western MN and southward along the MO River in the warm advection regime, and where instability will remain strong. Hail appears to be the main threat with this activity. Models suggest an increase in storm coverage, possibly an MCS, after 12Z Tuesday which is later than previously forecast. As such, have reduced severe probabilities for expected isolated coverage on Monday. Elsewhere, scattered storms are possible from the mid MS Valley across the OH Valley, where instability will remain strong but with rising heights aloft and weak shear. ..Jewell.. 08/17/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sat Aug 17 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis and Discussion... A negative-tilt shortwave trough will quickly move from southern Ontario across Quebec, followed closely by another area of cyclonic flow aloft amplifying over SK and MB. The southern periphery of the stronger flow aloft will affect parts of the Dakotas and MN late in the day when subtle height falls will commence. At the surface, a wind shift/weak front will approach the central Dakotas by late afternoon with a plume of mid to upper 60s F dewpoints spreading northward out of the central Plains ahead of the front. Strong instability will develop across this region, but capping will mitigate storm formation during much of the day. Isolated storms are possible along the front by late afternoon or early evening, aided by heating and modest low-level warm advection with 20 kt 850 mb flow. Additional nocturnal storms, likely elevated, are possible into western MN and southward along the MO River in the warm advection regime, and where instability will remain strong. Hail appears to be the main threat with this activity. Models suggest an increase in storm coverage, possibly an MCS, after 12Z Tuesday which is later than previously forecast. As such, have reduced severe probabilities for expected isolated coverage on Monday. Elsewhere, scattered storms are possible from the mid MS Valley across the OH Valley, where instability will remain strong but with rising heights aloft and weak shear. ..Jewell.. 08/17/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sat Aug 17 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis and Discussion... A negative-tilt shortwave trough will quickly move from southern Ontario across Quebec, followed closely by another area of cyclonic flow aloft amplifying over SK and MB. The southern periphery of the stronger flow aloft will affect parts of the Dakotas and MN late in the day when subtle height falls will commence. At the surface, a wind shift/weak front will approach the central Dakotas by late afternoon with a plume of mid to upper 60s F dewpoints spreading northward out of the central Plains ahead of the front. Strong instability will develop across this region, but capping will mitigate storm formation during much of the day. Isolated storms are possible along the front by late afternoon or early evening, aided by heating and modest low-level warm advection with 20 kt 850 mb flow. Additional nocturnal storms, likely elevated, are possible into western MN and southward along the MO River in the warm advection regime, and where instability will remain strong. Hail appears to be the main threat with this activity. Models suggest an increase in storm coverage, possibly an MCS, after 12Z Tuesday which is later than previously forecast. As such, have reduced severe probabilities for expected isolated coverage on Monday. Elsewhere, scattered storms are possible from the mid MS Valley across the OH Valley, where instability will remain strong but with rising heights aloft and weak shear. ..Jewell.. 08/17/2019 Read more