Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Sep 22 2019 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...OZARKS...MID MISSISSIPPI VALLEY AND SOUTHERN GREAT LAKES... CORRECTED FOR WORDING ...SUMMARY... Scattered storms capable of marginally severe wind gusts and hail will be possible from the southern Plains northeastward into the southern Great Lakes region this afternoon. ...Southern Plains/Ozarks/Mid Mississippi Valley/Southern Great Lakes... A southwest mid-level flow pattern will be in place today from the Great Plains into the Great Lakes as an upper-level trough moves across the High Plains. A cold front will advance southeastward into the southern Plains, Ozarks and mid Mississippi Valley. Ahead of the front, surface dewpoints in the mid to upper 60s F will contribute to some destabilization. This combined with large-scale ascent associated with the High Plains upper-level trough will result in scattered convective initiation along the moist corridor by afternoon. A low-level jet oriented southwest-to-northeast ahead of the front will also provide support for convective development. In addition to the moist airmass, moderate deep-layer shear is forecast to be in place along the front. The shear along with steepening low-level lapse rates will support a marginal wind damage threat during the mid to late afternoon. Hail will also accompany the stronger updrafts. At this point, instability is forecast to be the greatest in the southern Plains where the chance of a marginal severe threat appears to be slightly greater than in areas further to the northeast. ..Broyles/Elliott.. 09/22/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Sep 22 2019 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...OZARKS...MID MISSISSIPPI VALLEY AND SOUTHERN GREAT LAKES... CORRECTED FOR WORDING ...SUMMARY... Scattered storms capable of marginally severe wind gusts and hail will be possible from the southern Plains northeastward into the southern Great Lakes region this afternoon. ...Southern Plains/Ozarks/Mid Mississippi Valley/Southern Great Lakes... A southwest mid-level flow pattern will be in place today from the Great Plains into the Great Lakes as an upper-level trough moves across the High Plains. A cold front will advance southeastward into the southern Plains, Ozarks and mid Mississippi Valley. Ahead of the front, surface dewpoints in the mid to upper 60s F will contribute to some destabilization. This combined with large-scale ascent associated with the High Plains upper-level trough will result in scattered convective initiation along the moist corridor by afternoon. A low-level jet oriented southwest-to-northeast ahead of the front will also provide support for convective development. In addition to the moist airmass, moderate deep-layer shear is forecast to be in place along the front. The shear along with steepening low-level lapse rates will support a marginal wind damage threat during the mid to late afternoon. Hail will also accompany the stronger updrafts. At this point, instability is forecast to be the greatest in the southern Plains where the chance of a marginal severe threat appears to be slightly greater than in areas further to the northeast. ..Broyles/Elliott.. 09/22/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Sep 22 2019 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...OZARKS...MID MISSISSIPPI VALLEY AND SOUTHERN GREAT LAKES... CORRECTED FOR WORDING ...SUMMARY... Scattered storms capable of marginally severe wind gusts and hail will be possible from the southern Plains northeastward into the southern Great Lakes region this afternoon. ...Southern Plains/Ozarks/Mid Mississippi Valley/Southern Great Lakes... A southwest mid-level flow pattern will be in place today from the Great Plains into the Great Lakes as an upper-level trough moves across the High Plains. A cold front will advance southeastward into the southern Plains, Ozarks and mid Mississippi Valley. Ahead of the front, surface dewpoints in the mid to upper 60s F will contribute to some destabilization. This combined with large-scale ascent associated with the High Plains upper-level trough will result in scattered convective initiation along the moist corridor by afternoon. A low-level jet oriented southwest-to-northeast ahead of the front will also provide support for convective development. In addition to the moist airmass, moderate deep-layer shear is forecast to be in place along the front. The shear along with steepening low-level lapse rates will support a marginal wind damage threat during the mid to late afternoon. Hail will also accompany the stronger updrafts. At this point, instability is forecast to be the greatest in the southern Plains where the chance of a marginal severe threat appears to be slightly greater than in areas further to the northeast. ..Broyles/Elliott.. 09/22/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 AM CDT Sun Sep 22 2019 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF CENTRAL AND SOUTHERN ARIZONA... ...SUMMARY... Scattered storms, some severe with damaging wind and hail, are expected over much of Arizona Monday. ...Arizona... An upper low will drop south from NV toward the lower Colorado River Valley, providing large-scale lift as well as increasing shear profiles. At the surface, southern winds will persist over southeast CA into southern AZ ahead of the developing cold front. Heating as well as gulf moisture with 60s F dewpoints will result in MLCAPE on the order of 1000-1500 J/kg with little if any capping. Severe storms, including damaging wind gusts and hail, will develop during the afternoon over southern and central AZ, and possibly extreme eastern CA and southern NV where heating will be maximized. Low-level winds will be generally weak, but beneath increasing southwesterlies aloft. This will elongate hodographs, which will be mainly straight-line, supporting splitting cells capable of hail. Some cells may bow and produce damaging winds as well. Sporadic strong to severe storms will be possible late into the night over southern AZ as the air mass remains unstable prior to the cold front passage. ...Northeastern states... A potent shortwave trough will move rapidly east from the Great Lakes into the Northeast, providing increasing deep-layer shear as well as lift. At the surface, a narrow plume of low 60s F dewpoints will spread northward ahead of a cold front which will move across NY and PA during the day, and across New England overnight. Despite increasing wind fields, instability is forecast to be weak, averaging just a few hundred J/kg, and with poor deep-layer lapse rates. This should result in primarily non-severe storms along the cold front, capable of a few strong wind gusts as low-level mean winds average around 35 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 15% - Slight Hail: 15% - Slight ..Jewell.. 09/22/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 AM CDT Sun Sep 22 2019 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF CENTRAL AND SOUTHERN ARIZONA... ...SUMMARY... Scattered storms, some severe with damaging wind and hail, are expected over much of Arizona Monday. ...Arizona... An upper low will drop south from NV toward the lower Colorado River Valley, providing large-scale lift as well as increasing shear profiles. At the surface, southern winds will persist over southeast CA into southern AZ ahead of the developing cold front. Heating as well as gulf moisture with 60s F dewpoints will result in MLCAPE on the order of 1000-1500 J/kg with little if any capping. Severe storms, including damaging wind gusts and hail, will develop during the afternoon over southern and central AZ, and possibly extreme eastern CA and southern NV where heating will be maximized. Low-level winds will be generally weak, but beneath increasing southwesterlies aloft. This will elongate hodographs, which will be mainly straight-line, supporting splitting cells capable of hail. Some cells may bow and produce damaging winds as well. Sporadic strong to severe storms will be possible late into the night over southern AZ as the air mass remains unstable prior to the cold front passage. ...Northeastern states... A potent shortwave trough will move rapidly east from the Great Lakes into the Northeast, providing increasing deep-layer shear as well as lift. At the surface, a narrow plume of low 60s F dewpoints will spread northward ahead of a cold front which will move across NY and PA during the day, and across New England overnight. Despite increasing wind fields, instability is forecast to be weak, averaging just a few hundred J/kg, and with poor deep-layer lapse rates. This should result in primarily non-severe storms along the cold front, capable of a few strong wind gusts as low-level mean winds average around 35 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 15% - Slight Hail: 15% - Slight ..Jewell.. 09/22/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 AM CDT Sun Sep 22 2019 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF CENTRAL AND SOUTHERN ARIZONA... ...SUMMARY... Scattered storms, some severe with damaging wind and hail, are expected over much of Arizona Monday. ...Arizona... An upper low will drop south from NV toward the lower Colorado River Valley, providing large-scale lift as well as increasing shear profiles. At the surface, southern winds will persist over southeast CA into southern AZ ahead of the developing cold front. Heating as well as gulf moisture with 60s F dewpoints will result in MLCAPE on the order of 1000-1500 J/kg with little if any capping. Severe storms, including damaging wind gusts and hail, will develop during the afternoon over southern and central AZ, and possibly extreme eastern CA and southern NV where heating will be maximized. Low-level winds will be generally weak, but beneath increasing southwesterlies aloft. This will elongate hodographs, which will be mainly straight-line, supporting splitting cells capable of hail. Some cells may bow and produce damaging winds as well. Sporadic strong to severe storms will be possible late into the night over southern AZ as the air mass remains unstable prior to the cold front passage. ...Northeastern states... A potent shortwave trough will move rapidly east from the Great Lakes into the Northeast, providing increasing deep-layer shear as well as lift. At the surface, a narrow plume of low 60s F dewpoints will spread northward ahead of a cold front which will move across NY and PA during the day, and across New England overnight. Despite increasing wind fields, instability is forecast to be weak, averaging just a few hundred J/kg, and with poor deep-layer lapse rates. This should result in primarily non-severe storms along the cold front, capable of a few strong wind gusts as low-level mean winds average around 35 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 15% - Slight Hail: 15% - Slight ..Jewell.. 09/22/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 AM CDT Sun Sep 22 2019 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF CENTRAL AND SOUTHERN ARIZONA... ...SUMMARY... Scattered storms, some severe with damaging wind and hail, are expected over much of Arizona Monday. ...Arizona... An upper low will drop south from NV toward the lower Colorado River Valley, providing large-scale lift as well as increasing shear profiles. At the surface, southern winds will persist over southeast CA into southern AZ ahead of the developing cold front. Heating as well as gulf moisture with 60s F dewpoints will result in MLCAPE on the order of 1000-1500 J/kg with little if any capping. Severe storms, including damaging wind gusts and hail, will develop during the afternoon over southern and central AZ, and possibly extreme eastern CA and southern NV where heating will be maximized. Low-level winds will be generally weak, but beneath increasing southwesterlies aloft. This will elongate hodographs, which will be mainly straight-line, supporting splitting cells capable of hail. Some cells may bow and produce damaging winds as well. Sporadic strong to severe storms will be possible late into the night over southern AZ as the air mass remains unstable prior to the cold front passage. ...Northeastern states... A potent shortwave trough will move rapidly east from the Great Lakes into the Northeast, providing increasing deep-layer shear as well as lift. At the surface, a narrow plume of low 60s F dewpoints will spread northward ahead of a cold front which will move across NY and PA during the day, and across New England overnight. Despite increasing wind fields, instability is forecast to be weak, averaging just a few hundred J/kg, and with poor deep-layer lapse rates. This should result in primarily non-severe storms along the cold front, capable of a few strong wind gusts as low-level mean winds average around 35 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 15% - Slight Hail: 15% - Slight ..Jewell.. 09/22/2019 Read more

WW 0657 Status Updates
STATUS REPORT ON WW 657 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 55 S HLC TO 20 SSE SLN. ..SPC..09/22/19 ATTN...WFO...ICT...TOP...DDC...GID...OAX... STATUS REPORT FOR WS 657 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC027-029-041-051-053-061-089-105-117-123-127-131-141-143-149- 157-161-163-167-169-183-195-197-201-220440- KS . KANSAS COUNTIES INCLUDED ARE CLAY CLOUD DICKINSON ELLIS ELLSWORTH GEARY JEWELL LINCOLN MARSHALL MITCHELL MORRIS NEMAHA OSBORNE OTTAWA POTTAWATOMIE REPUBLIC RILEY ROOKS RUSSELL SALINE SMITH TREGO WABAUNSEE WASHINGTON NEC025-059-067-095-097-109-127-129-131-133-147-151-153-169- 220440- NE . NEBRASKA COUNTIES INCLUDED ARE CASS FILLMORE GAGE JEFFERSON JOHNSON LANCASTER NEMAHA NUCKOLLS OTOE Read more

WW 657 SEVERE TSTM KS NE 212210Z - 220500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 657 NWS Storm Prediction Center Norman OK 510 PM CDT Sat Sep 21 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southwest to northeast Kansas Southeast Nebraska * Effective this Saturday afternoon from 510 PM until Midnight CDT. * 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...Scattered thunderstorms will develop this evening from southwest Kansas into southeast Nebraska with primary threats of large hail and damaging wind. This activity should evolve into one or more clusters with the severe threat waning towards late evening as it transitions to predominantly a heavy rainfall hazard. The severe thunderstorm watch area is approximately along and 70 statute miles east and west of a line from 35 miles northeast of Beatrice NE to 10 miles east southeast of Dodge City KS. 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. && 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 25035. ...Grams Read more

MD 2000 CONCERNING SEVERE THUNDERSTORM WATCH 657... FOR KS...SOUTHWEST IA...NORTHWEST MO
Mesoscale Discussion 2000 NWS Storm Prediction Center Norman OK 1032 PM CDT Sat Sep 21 2019 Areas affected...KS...Southwest IA...Northwest MO Concerning...Severe Thunderstorm Watch 657... Valid 220332Z - 220530Z The severe weather threat for Severe Thunderstorm Watch 657 continues. SUMMARY...Severe threat is gradually shifting east and waning. New WW is not anticipated. DISCUSSION...Isolated severe wind gusts have been noted within the last hour along strongest portion of the squall line near CNK. This activity is shifting east along the NE/KS border and should progress east of ww657 in the next 1-2hr as LLJ focuses into this portion of the eastern Plains. While convection should remain organized, overall severe threat appears to be decreasing, especially as thunderstorms shift east of the MO river. A new WW is not anticipated downstream. ..Darrow.. 09/22/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...OAX...TOP...ICT...GID...DDC...GLD... LAT...LON 38920084 39799779 41489533 40269485 38699759 38400062 38920084 Read more

WW 0657 Status Updates
STATUS REPORT ON WW 657 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DARROW..09/22/19 ATTN...WFO...ICT...TOP...DDC...GID...OAX... STATUS REPORT FOR WS 657 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC009-027-029-041-047-051-053-055-057-061-067-069-081-083-089- 101-105-113-117-123-127-131-135-141-143-145-149-157-159-161-163- 165-167-169-183-185-195-197-201-220240- KS . KANSAS COUNTIES INCLUDED ARE BARTON CLAY CLOUD DICKINSON EDWARDS ELLIS ELLSWORTH FINNEY FORD GEARY GRANT GRAY HASKELL HODGEMAN JEWELL LANE LINCOLN MCPHERSON MARSHALL MITCHELL MORRIS NEMAHA NESS OSBORNE OTTAWA PAWNEE POTTAWATOMIE REPUBLIC RICE RILEY ROOKS RUSH RUSSELL SALINE SMITH STAFFORD TREGO WABAUNSEE WASHINGTON NEC025-055-059-067-095-097-109-127-129-131-133-147-151-153-155- 169-220240- NE Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Sat Sep 21 2019 Valid 220100Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE LOWER TO MID MISSOURI VALLEY... ...SUMMARY... Large hail, damaging winds, and perhaps a couple of tornadoes remain possible this evening from Kansas to Iowa. A marginal severe threat is also possible across parts of north-central Minnesota into northwest Wisconsin. ...Central Plains/Lower to Mid Missouri Valley... The latest water vapor imagery shows southwest mid-level flow over the central U.S. At the surface, a cold front is analyzed from western Kansas northeastward into southeast Nebraska. A line of strong to severe thunderstorms is ongoing along the front. Other more isolated cells are located eastward across the warm sector. Model forecasts gradually increase convective coverage this evening as an MCS develops and move northeastward across northeast Kansas, northwest Missouri and southern Iowa. The airmass along this corridor is moderately unstable with the Topeka observed 00Z sounding showing about 1500 J/kg of MLCAPE. The wind profile has strong directional shear in the lowest 2 km AGL with 40 kt of 0-6 km shear. This should support supercell development with isolated large hail with the stronger cells in the line. As the line grows upscale this evening, the wind damage threat will likely increase. The greatest chance for wind damage will be associated with bowing line segments. A tornado or two can not be ruled out with rotating cells embedded in the line or with discrete cells ahead of the line...see MCD 1998 and 1999. ...Upper Mississippi Valley... The latest water vapor imagery shows an upper-level trough over the northern High Plains extending southwestward into the Intermountain West. Southwest mid-level flow is in place in the northern Plains and upper Mississippi Valley. At the surface, a cold front is analyzed across central and northern Minnesota. Thunderstorms are ongoing along the front in north-central Minnesota and ahead of the front in northwest Wisconsin. Model forecasts gradually move this activity eastward and slowly decrease convective coverage. An axis of instability is located from northwest Iowa into northern Wisconsin where MLCAPE is estimated in the 2000 to 2500 J/kg. This is evident on the Minneapolis 00Z sounding. In addition, the sounding has a wind profile with 45 kt of 0-6 km shear. Steep lapse rates are also evident from the surface to mid-levels. This could be favorable for rotating storms with cells that remain discrete. This cells would have a wind damage and hail threat. As instability weakens over the next few hours, the severe threat is expected to further diminish. ..Broyles.. 09/22/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Sat Sep 21 2019 Valid 220100Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE LOWER TO MID MISSOURI VALLEY... ...SUMMARY... Large hail, damaging winds, and perhaps a couple of tornadoes remain possible this evening from Kansas to Iowa. A marginal severe threat is also possible across parts of north-central Minnesota into northwest Wisconsin. ...Central Plains/Lower to Mid Missouri Valley... The latest water vapor imagery shows southwest mid-level flow over the central U.S. At the surface, a cold front is analyzed from western Kansas northeastward into southeast Nebraska. A line of strong to severe thunderstorms is ongoing along the front. Other more isolated cells are located eastward across the warm sector. Model forecasts gradually increase convective coverage this evening as an MCS develops and move northeastward across northeast Kansas, northwest Missouri and southern Iowa. The airmass along this corridor is moderately unstable with the Topeka observed 00Z sounding showing about 1500 J/kg of MLCAPE. The wind profile has strong directional shear in the lowest 2 km AGL with 40 kt of 0-6 km shear. This should support supercell development with isolated large hail with the stronger cells in the line. As the line grows upscale this evening, the wind damage threat will likely increase. The greatest chance for wind damage will be associated with bowing line segments. A tornado or two can not be ruled out with rotating cells embedded in the line or with discrete cells ahead of the line...see MCD 1998 and 1999. ...Upper Mississippi Valley... The latest water vapor imagery shows an upper-level trough over the northern High Plains extending southwestward into the Intermountain West. Southwest mid-level flow is in place in the northern Plains and upper Mississippi Valley. At the surface, a cold front is analyzed across central and northern Minnesota. Thunderstorms are ongoing along the front in north-central Minnesota and ahead of the front in northwest Wisconsin. Model forecasts gradually move this activity eastward and slowly decrease convective coverage. An axis of instability is located from northwest Iowa into northern Wisconsin where MLCAPE is estimated in the 2000 to 2500 J/kg. This is evident on the Minneapolis 00Z sounding. In addition, the sounding has a wind profile with 45 kt of 0-6 km shear. Steep lapse rates are also evident from the surface to mid-levels. This could be favorable for rotating storms with cells that remain discrete. This cells would have a wind damage and hail threat. As instability weakens over the next few hours, the severe threat is expected to further diminish. ..Broyles.. 09/22/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Sat Sep 21 2019 Valid 220100Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE LOWER TO MID MISSOURI VALLEY... ...SUMMARY... Large hail, damaging winds, and perhaps a couple of tornadoes remain possible this evening from Kansas to Iowa. A marginal severe threat is also possible across parts of north-central Minnesota into northwest Wisconsin. ...Central Plains/Lower to Mid Missouri Valley... The latest water vapor imagery shows southwest mid-level flow over the central U.S. At the surface, a cold front is analyzed from western Kansas northeastward into southeast Nebraska. A line of strong to severe thunderstorms is ongoing along the front. Other more isolated cells are located eastward across the warm sector. Model forecasts gradually increase convective coverage this evening as an MCS develops and move northeastward across northeast Kansas, northwest Missouri and southern Iowa. The airmass along this corridor is moderately unstable with the Topeka observed 00Z sounding showing about 1500 J/kg of MLCAPE. The wind profile has strong directional shear in the lowest 2 km AGL with 40 kt of 0-6 km shear. This should support supercell development with isolated large hail with the stronger cells in the line. As the line grows upscale this evening, the wind damage threat will likely increase. The greatest chance for wind damage will be associated with bowing line segments. A tornado or two can not be ruled out with rotating cells embedded in the line or with discrete cells ahead of the line...see MCD 1998 and 1999. ...Upper Mississippi Valley... The latest water vapor imagery shows an upper-level trough over the northern High Plains extending southwestward into the Intermountain West. Southwest mid-level flow is in place in the northern Plains and upper Mississippi Valley. At the surface, a cold front is analyzed across central and northern Minnesota. Thunderstorms are ongoing along the front in north-central Minnesota and ahead of the front in northwest Wisconsin. Model forecasts gradually move this activity eastward and slowly decrease convective coverage. An axis of instability is located from northwest Iowa into northern Wisconsin where MLCAPE is estimated in the 2000 to 2500 J/kg. This is evident on the Minneapolis 00Z sounding. In addition, the sounding has a wind profile with 45 kt of 0-6 km shear. Steep lapse rates are also evident from the surface to mid-levels. This could be favorable for rotating storms with cells that remain discrete. This cells would have a wind damage and hail threat. As instability weakens over the next few hours, the severe threat is expected to further diminish. ..Broyles.. 09/22/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Sat Sep 21 2019 Valid 220100Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE LOWER TO MID MISSOURI VALLEY... ...SUMMARY... Large hail, damaging winds, and perhaps a couple of tornadoes remain possible this evening from Kansas to Iowa. A marginal severe threat is also possible across parts of north-central Minnesota into northwest Wisconsin. ...Central Plains/Lower to Mid Missouri Valley... The latest water vapor imagery shows southwest mid-level flow over the central U.S. At the surface, a cold front is analyzed from western Kansas northeastward into southeast Nebraska. A line of strong to severe thunderstorms is ongoing along the front. Other more isolated cells are located eastward across the warm sector. Model forecasts gradually increase convective coverage this evening as an MCS develops and move northeastward across northeast Kansas, northwest Missouri and southern Iowa. The airmass along this corridor is moderately unstable with the Topeka observed 00Z sounding showing about 1500 J/kg of MLCAPE. The wind profile has strong directional shear in the lowest 2 km AGL with 40 kt of 0-6 km shear. This should support supercell development with isolated large hail with the stronger cells in the line. As the line grows upscale this evening, the wind damage threat will likely increase. The greatest chance for wind damage will be associated with bowing line segments. A tornado or two can not be ruled out with rotating cells embedded in the line or with discrete cells ahead of the line...see MCD 1998 and 1999. ...Upper Mississippi Valley... The latest water vapor imagery shows an upper-level trough over the northern High Plains extending southwestward into the Intermountain West. Southwest mid-level flow is in place in the northern Plains and upper Mississippi Valley. At the surface, a cold front is analyzed across central and northern Minnesota. Thunderstorms are ongoing along the front in north-central Minnesota and ahead of the front in northwest Wisconsin. Model forecasts gradually move this activity eastward and slowly decrease convective coverage. An axis of instability is located from northwest Iowa into northern Wisconsin where MLCAPE is estimated in the 2000 to 2500 J/kg. This is evident on the Minneapolis 00Z sounding. In addition, the sounding has a wind profile with 45 kt of 0-6 km shear. Steep lapse rates are also evident from the surface to mid-levels. This could be favorable for rotating storms with cells that remain discrete. This cells would have a wind damage and hail threat. As instability weakens over the next few hours, the severe threat is expected to further diminish. ..Broyles.. 09/22/2019 Read more

MD 1999 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHWEST/CENTRAL IA...NORTHWEST MO
Mesoscale Discussion 1999 NWS Storm Prediction Center Norman OK 0754 PM CDT Sat Sep 21 2019 Areas affected...Southwest/Central IA...Northwest MO Concerning...Severe potential...Watch possible Valid 220054Z - 220300Z Probability of Watch Issuance...40 percent SUMMARY...Strong thunderstorms are expected to spread/develop across southwest into central IA. A few storms may produce large hail and locally severe wind gusts. DISCUSSION...Thunderstorms have increased markedly along a corridor from north of DDC into southeast NE over the last few hours. This pre-frontal activity should continue to expand/develop into IA over the next 1-3 hours as deep, moist southwesterly steering current encourages northeast movement. Plains convection initially developed within a steep-lapse rate environment, however buoyancy is considerably weaker over IA where surface temperatures are only in the low-mid 70s. Latest thinking is robust updrafts will spread east of ww657 but likely weaken a bit downstream with more marginal hail and only isolated strong/severe wind gusts possible. ..Darrow/Grams.. 09/22/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...EAX...OAX... LAT...LON 41469613 42559346 41529256 40239506 40459638 41469613 Read more

MD 1998 CONCERNING SEVERE THUNDERSTORM WATCH 657... FOR KANSAS...SOUTHEAST NEBRASKA
Mesoscale Discussion 1998 NWS Storm Prediction Center Norman OK 0725 PM CDT Sat Sep 21 2019 Areas affected...Kansas...Southeast Nebraska Concerning...Severe Thunderstorm Watch 657... Valid 220025Z - 220230Z The severe weather threat for Severe Thunderstorm Watch 657 continues. SUMMARY...Numerous thunderstorms will continue across the northwestern half of ww657. Isolated large hail and locally severe wind gusts are expected. DISCUSSION...Pre-frontal convection continues to expand along a corridor from just north of DDC into extreme southeast NE. This activity is developing along northern edged of higher-PW plume within a zone of low-level confluence. Earlier discrete supercell structures are losing their identity with multiple storm mergers expected to result in a southwest-northeast near-continues line over the next few hours. Even so, latest hail algorithm suggests the strongest updrafts remain capable of producing hail on the order of 1-1.5". Strong-severe convective event is expected to linger well into the overnight hours as LLJ strengthens over northeast KS later this evening. ..Darrow.. 09/22/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...OAX...TOP...ICT...GID...DDC... LAT...LON 37710109 40649761 40639495 37719852 37710109 Read more

WW 0657 Status Updates
STATUS REPORT ON WW 657 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SPC..09/21/19 ATTN...WFO...ICT...TOP...DDC...GID...OAX... STATUS REPORT FOR WS 657 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC009-027-029-041-047-051-053-055-057-061-067-069-081-083-089- 101-105-113-117-123-127-131-135-141-143-145-149-157-159-161-163- 165-167-169-183-185-195-197-201-220040- KS . KANSAS COUNTIES INCLUDED ARE BARTON CLAY CLOUD DICKINSON EDWARDS ELLIS ELLSWORTH FINNEY FORD GEARY GRANT GRAY HASKELL HODGEMAN JEWELL LANE LINCOLN MCPHERSON MARSHALL MITCHELL MORRIS NEMAHA NESS OSBORNE OTTAWA PAWNEE POTTAWATOMIE REPUBLIC RICE RILEY ROOKS RUSH RUSSELL SALINE SMITH STAFFORD TREGO WABAUNSEE WASHINGTON NEC025-059-067-095-097-109-127-129-131-133-147-151-169-220040- NE . NEBRASKA COUNTIES INCLUDED ARE Read more

No Mesoscale Discussions are in effect as of Sat Sep 21 23:14:02 UTC 2019.

WW 0657 Status Updates
STATUS FOR WATCH 0657 HAS NOT BEEN ISSUED YET Read more