Severe Storms

WW 640 TORNADO NE SD WY 101950Z - 110300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 640 NWS Storm Prediction Center Norman OK 150 PM MDT Tue Sep 10 2019 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Northern Nebraska Southern South Dakota Eastern Wyoming * Effective this Tuesday afternoon and evening from 150 PM until 900 PM MDT. * Primary threats include... A couple tornadoes possible Scattered large hail likely with isolated very large hail events to 3 inches in diameter possible Scattered damaging wind gusts to 70 mph likely SUMMARY...Thunderstorms will intensify this afternoon over eastern Wyoming, and along a boundary over northern Nebraska. These storms will affect the watch area through the evening, posing a risk of large hail, damaging wind gusts, and a few tornadoes. The tornado watch area is approximately along and 60 statute miles north and south of a line from 45 miles northwest of Douglas WY to 30 miles northeast of Ainsworth NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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 3 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 26030. ...Hart Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

WW 0640 Status Updates
STATUS FOR WATCH 0640 HAS NOT BEEN ISSUED YET Read more

MD 1949 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST KANSAS...SOUTHEAST COLORADO...NORTHWEST TEXAS PANHANDLE...WESTERN OKLAHOMA PANHANDLE...NORTHEAST NEW MEXICO
Mesoscale Discussion 1949 NWS Storm Prediction Center Norman OK 0238 PM CDT Tue Sep 10 2019 Areas affected...Southwest Kansas...Southeast Colorado...northwest Texas Panhandle...western Oklahoma Panhandle...northeast New Mexico Concerning...Severe potential...Watch unlikely Valid 101938Z - 102145Z Probability of Watch Issuance...5 percent SUMMARY...A few isolated storms capable of strong/severe wind gusts are possible this afternoon. This diurnally-driven activity should cease after sunset. A WW is not likely. DISCUSSION...Cumulus have been deepening within the lee trough into southeast Colorado and northeast New Mexico over the past hour. Isolated storms have already developed with a few more storms possible within the next couple hours. With stronger flow/shear displaced to the northwest, storms will struggle to organize and propagate very far eastward into greater buoyancy. However, strong surface heating has steepened low-level lapse rates significantly which will allow a few strong/severe wind gusts to accompany this activity. With weak upper-level support, this disorganized activity will likely cease after sunset. A WW is not likely. ..Wendt/Hart.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DDC...GLD...AMA...PUB...ABQ... LAT...LON 36470371 38820207 38970169 38920116 38410076 37360091 36380167 35150271 34820358 35190416 35520435 36470371 Read more

MD 1948 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY FOR NE PANHANDLE...WESTERN/CENTRAL NE...SOUTH-CENTRAL SD
Mesoscale Discussion 1948 NWS Storm Prediction Center Norman OK 0225 PM CDT Tue Sep 10 2019 Areas affected...NE Panhandle...Western/Central NE...South-Central SD Concerning...Severe potential...Tornado Watch likely Valid 101925Z - 102130Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorm initiation is anticipated over north-central NE/south-central SD later this afternoon. All severe hazards, including tornadoes, are possible with the initial development. Upscale growth into a strong, forward-propagating MCS anticipated thereafter. DISCUSSION...Recent surface analysis places a warm front from just south of the YKN (in far southeast SD) west-southwestward across north-central NE and into far southeast WY. Moist conditions exist south of this front with dewpoints in the upper 60s/low 70s. These moist conditions combined with steep mid-level lapse rates are contributing to moderate to strong buoyancy. Additionally, southeasterly surface winds beneath increasing southwesterly flow results in a veering wind profile and strong deep layer shear. Expectation is for storm to develop quickly along and near the front once convective inhibition erodes this afternoon. An initially discrete mode is anticipated but close storm proximity suggests clustering could occur quickly. Even so, favorable low-level shear profiles and ample low-level moisture suggest tornadoes are possible. A forward-propagating MCS will likely develop out of the storm cluster as cold pools amalgamate. Given the overall environment, some significant wind gusts (i.e. 74+ mph) are possible within this MCS. ..Nauslar/Hart.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...ABR...LBF...UNR...CYS... LAT...LON 42370311 43190254 43550192 43670060 43579968 43129893 42139884 41460004 41370260 42370311 Read more

No watches are valid as of Tue Sep 10 18:53:06 UTC 2019.

MD 1947 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR EASTERN WY...FAR WESTERN SD...WESTERN NE PANHANDLE
Mesoscale Discussion 1947 NWS Storm Prediction Center Norman OK 0151 PM CDT Tue Sep 10 2019 Areas affected...Eastern WY...Far Western SD...Western NE Panhandle Concerning...Severe potential...Watch likely Valid 101851Z - 102045Z Probability of Watch Issuance...80 percent SUMMARY...Increasing thunderstorm coverage is anticipated this afternoon, with some supercells likely. Very large hail, strong wind gusts, and a tornado or two possible. DISCUSSION...Thunderstorm coverage is expected to increase this afternoon as forcing for ascent attendant to an approaching shortwave trough interacts with a diurnally destabilizing boundary layer. Destabilization across much of the region will be driven primarily by increasing surface temperatures and boundary-layer mixing, but some modest moisture advection is anticipated as well. Strong moisture advection is possible across southeast WY and the western NE Panhandle. Recent surface analysis reveals the dewpoint has increased 4 to 6 degrees F over the past 3 hours as the warm front moves northward. Attempts at sustained deep convection across the region have failed thus far, likely due to minimal buoyancy. However, continued attempts are anticipated, with more sustained/organized updrafts expected. Given the supercell wind profile in place, discrete supercells are possible. Primary threat with these discrete storms would be very large hail, although strong wind gusts and a tornado or two are also possible. Upscale growth/linear transition is then anticipated later this evening. ..Mosier/Hart.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...UNR...CYS...BYZ...RIW... LAT...LON 42880635 44340650 44800563 44390399 41850323 41030364 41030534 42880635 Read more

MD 1946 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN GREAT BASIN...WESTERN WYOMING...FAR NORTHWEST COLORADO
Mesoscale Discussion 1946 NWS Storm Prediction Center Norman OK 0114 PM CDT Tue Sep 10 2019 Areas affected...Portions of northern Great Basin...western Wyoming...far northwest Colorado Concerning...Severe potential...Watch unlikely Valid 101814Z - 102015Z Probability of Watch Issuance...20 percent SUMMARY...Isolated large hail and strong/severe wind gusts possible this afternoon. A WW is not anticipated. DISCUSSION...Strong forcing for ascent is evident on water vapor imagery as a mid-level jet streak rounds the base of trough across the Pacific Northwest. Storms have begun to develop along the higher terrain southwest of SLC into northeast NV and southeast ID. MLCIN still exists away from the higher terrain, but continued heating should result in a gradual increase in storm coverage/intensity downstream. Current objective mesoanalysis shows very meager MLCAPE of 250-500 J/kg. While no marked increase in buoyancy is expected, cloud free areas may see 500-1000 J/kg MLCAPE by late afternoon. With 35-45 kts of effective deep-layer shear, long hodographs, and steep mid-level lapse rates (8+ C/km observed on 12Z SLC/RIW/BOI soundings), large hail will be possible with the stronger storms. Isolated strong/severe wind gusts will be possible with fairly deep boundary layers and strong flow aloft. A WW is not anticipated this afternoon as limited buoyancy will likely temper the overall severe threat. ..Wendt.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...RIW...GJT...SLC...PIH...BOI...LKN... LAT...LON 41961618 42551556 43441358 44021226 43340974 42330892 41110828 39910839 39480866 39141039 40331162 41051230 41531312 41261447 41131541 41501618 41761620 41961618 Read more

No Mesoscale Discussions are in effect as of Tue Sep 10 18:02:07 UTC 2019.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1259 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z The ongoing forecast is on track and no changes are needed. See the previous forecast below for more information. ..Cook.. 09/10/2019 .PREV DISCUSSION... /ISSUED 0204 AM CDT Tue Sep 10 2019/ ...Synopsis... A pronounced mid-level shortwave trough will move across the western CONUS during the Day 2/Wednesday period. Stronger flow aloft will accompany the through, with a belt of 50+ knot 500 mb flow expected to traverse the Four Corners region by late afternoon. At the same time, deep boundary layer mixing may occur across parts of the Four Corners, promoting modest potential for wildfire spread. ...Parts of the Four Corners area... By afternoon peak heating, 15-25 mph sustained westerly winds and 15-20% RH will become commonplace across portions of the northern Colorado Plateau, to the windward side of the central Rockies. Given modestly dry fuels in place, an elevated area was delineated to account for marginal wildfire-spread potential in this area. ...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 1259 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z The ongoing forecast is on track and no changes are needed. See the previous forecast below for more information. ..Cook.. 09/10/2019 .PREV DISCUSSION... /ISSUED 0204 AM CDT Tue Sep 10 2019/ ...Synopsis... A pronounced mid-level shortwave trough will move across the western CONUS during the Day 2/Wednesday period. Stronger flow aloft will accompany the through, with a belt of 50+ knot 500 mb flow expected to traverse the Four Corners region by late afternoon. At the same time, deep boundary layer mixing may occur across parts of the Four Corners, promoting modest potential for wildfire spread. ...Parts of the Four Corners area... By afternoon peak heating, 15-25 mph sustained westerly winds and 15-20% RH will become commonplace across portions of the northern Colorado Plateau, to the windward side of the central Rockies. Given modestly dry fuels in place, an elevated area was delineated to account for marginal wildfire-spread potential in this area. ...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 1259 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z The ongoing forecast is on track and no changes are needed. See the previous forecast below for more information. ..Cook.. 09/10/2019 .PREV DISCUSSION... /ISSUED 0204 AM CDT Tue Sep 10 2019/ ...Synopsis... A pronounced mid-level shortwave trough will move across the western CONUS during the Day 2/Wednesday period. Stronger flow aloft will accompany the through, with a belt of 50+ knot 500 mb flow expected to traverse the Four Corners region by late afternoon. At the same time, deep boundary layer mixing may occur across parts of the Four Corners, promoting modest potential for wildfire spread. ...Parts of the Four Corners area... By afternoon peak heating, 15-25 mph sustained westerly winds and 15-20% RH will become commonplace across portions of the northern Colorado Plateau, to the windward side of the central Rockies. Given modestly dry fuels in place, an elevated area was delineated to account for marginal wildfire-spread potential in this area. ...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 1259 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z The ongoing forecast is on track and no changes are needed. See the previous forecast below for more information. ..Cook.. 09/10/2019 .PREV DISCUSSION... /ISSUED 0204 AM CDT Tue Sep 10 2019/ ...Synopsis... A pronounced mid-level shortwave trough will move across the western CONUS during the Day 2/Wednesday period. Stronger flow aloft will accompany the through, with a belt of 50+ knot 500 mb flow expected to traverse the Four Corners region by late afternoon. At the same time, deep boundary layer mixing may occur across parts of the Four Corners, promoting modest potential for wildfire spread. ...Parts of the Four Corners area... By afternoon peak heating, 15-25 mph sustained westerly winds and 15-20% RH will become commonplace across portions of the northern Colorado Plateau, to the windward side of the central Rockies. Given modestly dry fuels in place, an elevated area was delineated to account for marginal wildfire-spread potential in this area. ...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 Sep 10 2019 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms capable of producing large hail, damaging winds, and isolated tornadoes are expected to develop on Wednesday from parts of the northern and central Plains eastward into the Upper Midwest. ...Northern/Central Plains into the Upper Mississippi Valley... An upper trough over the western CONUS will develop eastward to the vicinity of the northern/central Rockies by Wednesday evening. A mid-level jet attendant to this trough is forecast to overspread parts of the northern/central High Plains by Wednesday afternoon. Although low-level moisture will be more limited across the High Plains compared to locations farther east, steep mid-level lapse rates should be present across this area. Storms are expected to increase in coverage and intensity as they move eastward off the higher terrain and into northeastern CO, far eastern WY, and the NE Panhandle by late Wednesday afternoon. Shear profiles will be supportive of supercells, and large hail will likely be the main threat initially with these discrete storms. Some of the hail could be very large, especially into the NE Panhandle and vicinity where instability is forecast to quickly increase. Storms should grow upscale Wednesday evening into central NE and south-central SD as a southerly low-level jet strengthens and as storms encounter greater instability along/east of a surface front. Damaging winds will likely become the primary threat with eastward extent, and some of the wind gusts could be significant given the strong shear and instability that is forecast. Isolated tornadoes may also occur in the transition from a mainly discrete to more linear mode Wednesday evening as low-level shear strengthens in tandem with the low-level jet. Additional storms posing an isolated threat for all severe hazards will probably develop Wednesday evening in a low-level warm air advection regime across eastern SD into southern MN. ...Great Lakes into the Mid-Atlantic... Storms will likely be ongoing Wednesday morning across parts of the Upper Midwest. Stronger mid-level flow associated with an upper trough will likely remain displaced to the north in Canada. But, some modest enhancement to the mid-level westerlies should overlie the Great Lakes region into parts of the OH Valley and Mid-Atlantic to the south of a surface front Wednesday afternoon. Storms may form and/or re-intensify in several small clusters and move east-southeastward across these areas through Wednesday evening. Moderate to strong instability along with weak but sufficient shear will probably support modest storm organization. Isolated strong to damaging winds should be the main threat with these storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% SIG - Enhanced Hail: 15% SIG - Slight ..Gleason.. 09/10/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms capable of producing large hail, damaging winds, and isolated tornadoes are expected to develop on Wednesday from parts of the northern and central Plains eastward into the Upper Midwest. ...Northern/Central Plains into the Upper Mississippi Valley... An upper trough over the western CONUS will develop eastward to the vicinity of the northern/central Rockies by Wednesday evening. A mid-level jet attendant to this trough is forecast to overspread parts of the northern/central High Plains by Wednesday afternoon. Although low-level moisture will be more limited across the High Plains compared to locations farther east, steep mid-level lapse rates should be present across this area. Storms are expected to increase in coverage and intensity as they move eastward off the higher terrain and into northeastern CO, far eastern WY, and the NE Panhandle by late Wednesday afternoon. Shear profiles will be supportive of supercells, and large hail will likely be the main threat initially with these discrete storms. Some of the hail could be very large, especially into the NE Panhandle and vicinity where instability is forecast to quickly increase. Storms should grow upscale Wednesday evening into central NE and south-central SD as a southerly low-level jet strengthens and as storms encounter greater instability along/east of a surface front. Damaging winds will likely become the primary threat with eastward extent, and some of the wind gusts could be significant given the strong shear and instability that is forecast. Isolated tornadoes may also occur in the transition from a mainly discrete to more linear mode Wednesday evening as low-level shear strengthens in tandem with the low-level jet. Additional storms posing an isolated threat for all severe hazards will probably develop Wednesday evening in a low-level warm air advection regime across eastern SD into southern MN. ...Great Lakes into the Mid-Atlantic... Storms will likely be ongoing Wednesday morning across parts of the Upper Midwest. Stronger mid-level flow associated with an upper trough will likely remain displaced to the north in Canada. But, some modest enhancement to the mid-level westerlies should overlie the Great Lakes region into parts of the OH Valley and Mid-Atlantic to the south of a surface front Wednesday afternoon. Storms may form and/or re-intensify in several small clusters and move east-southeastward across these areas through Wednesday evening. Moderate to strong instability along with weak but sufficient shear will probably support modest storm organization. Isolated strong to damaging winds should be the main threat with these storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% SIG - Enhanced Hail: 15% SIG - Slight ..Gleason.. 09/10/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms capable of producing large hail, damaging winds, and isolated tornadoes are expected to develop on Wednesday from parts of the northern and central Plains eastward into the Upper Midwest. ...Northern/Central Plains into the Upper Mississippi Valley... An upper trough over the western CONUS will develop eastward to the vicinity of the northern/central Rockies by Wednesday evening. A mid-level jet attendant to this trough is forecast to overspread parts of the northern/central High Plains by Wednesday afternoon. Although low-level moisture will be more limited across the High Plains compared to locations farther east, steep mid-level lapse rates should be present across this area. Storms are expected to increase in coverage and intensity as they move eastward off the higher terrain and into northeastern CO, far eastern WY, and the NE Panhandle by late Wednesday afternoon. Shear profiles will be supportive of supercells, and large hail will likely be the main threat initially with these discrete storms. Some of the hail could be very large, especially into the NE Panhandle and vicinity where instability is forecast to quickly increase. Storms should grow upscale Wednesday evening into central NE and south-central SD as a southerly low-level jet strengthens and as storms encounter greater instability along/east of a surface front. Damaging winds will likely become the primary threat with eastward extent, and some of the wind gusts could be significant given the strong shear and instability that is forecast. Isolated tornadoes may also occur in the transition from a mainly discrete to more linear mode Wednesday evening as low-level shear strengthens in tandem with the low-level jet. Additional storms posing an isolated threat for all severe hazards will probably develop Wednesday evening in a low-level warm air advection regime across eastern SD into southern MN. ...Great Lakes into the Mid-Atlantic... Storms will likely be ongoing Wednesday morning across parts of the Upper Midwest. Stronger mid-level flow associated with an upper trough will likely remain displaced to the north in Canada. But, some modest enhancement to the mid-level westerlies should overlie the Great Lakes region into parts of the OH Valley and Mid-Atlantic to the south of a surface front Wednesday afternoon. Storms may form and/or re-intensify in several small clusters and move east-southeastward across these areas through Wednesday evening. Moderate to strong instability along with weak but sufficient shear will probably support modest storm organization. Isolated strong to damaging winds should be the main threat with these storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% SIG - Enhanced Hail: 15% SIG - Slight ..Gleason.. 09/10/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Sep 10 2019 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms capable of producing large hail, damaging winds, and isolated tornadoes are expected to develop on Wednesday from parts of the northern and central Plains eastward into the Upper Midwest. ...Northern/Central Plains into the Upper Mississippi Valley... An upper trough over the western CONUS will develop eastward to the vicinity of the northern/central Rockies by Wednesday evening. A mid-level jet attendant to this trough is forecast to overspread parts of the northern/central High Plains by Wednesday afternoon. Although low-level moisture will be more limited across the High Plains compared to locations farther east, steep mid-level lapse rates should be present across this area. Storms are expected to increase in coverage and intensity as they move eastward off the higher terrain and into northeastern CO, far eastern WY, and the NE Panhandle by late Wednesday afternoon. Shear profiles will be supportive of supercells, and large hail will likely be the main threat initially with these discrete storms. Some of the hail could be very large, especially into the NE Panhandle and vicinity where instability is forecast to quickly increase. Storms should grow upscale Wednesday evening into central NE and south-central SD as a southerly low-level jet strengthens and as storms encounter greater instability along/east of a surface front. Damaging winds will likely become the primary threat with eastward extent, and some of the wind gusts could be significant given the strong shear and instability that is forecast. Isolated tornadoes may also occur in the transition from a mainly discrete to more linear mode Wednesday evening as low-level shear strengthens in tandem with the low-level jet. Additional storms posing an isolated threat for all severe hazards will probably develop Wednesday evening in a low-level warm air advection regime across eastern SD into southern MN. ...Great Lakes into the Mid-Atlantic... Storms will likely be ongoing Wednesday morning across parts of the Upper Midwest. Stronger mid-level flow associated with an upper trough will likely remain displaced to the north in Canada. But, some modest enhancement to the mid-level westerlies should overlie the Great Lakes region into parts of the OH Valley and Mid-Atlantic to the south of a surface front Wednesday afternoon. Storms may form and/or re-intensify in several small clusters and move east-southeastward across these areas through Wednesday evening. Moderate to strong instability along with weak but sufficient shear will probably support modest storm organization. Isolated strong to damaging winds should be the main threat with these storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% SIG - Enhanced Hail: 15% SIG - Slight ..Gleason.. 09/10/2019 Read more