Severe Storms

WW 0557 Status Updates
STATUS REPORT ON WW 557 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNW ANW TO 20 NE ANW TO 25 NNW ONL TO 20 NNE ONL TO 45 W OFK TO 20 WNW OLU. ..EDWARDS..08/07/19 ATTN...WFO...OAX...LBF...GID...FSD...UNR... STATUS REPORT FOR WS 557 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-011-017-041-071-077-089-093-115-125-149-163-175-183- 070740- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOONE BROWN CUSTER GARFIELD GREELEY HOLT HOWARD LOUP NANCE ROCK SHERMAN VALLEY WHEELER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0557 Status Updates
STATUS REPORT ON WW 557 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNW ANW TO 20 NE ANW TO 25 NNW ONL TO 20 NNE ONL TO 45 W OFK TO 20 WNW OLU. ..EDWARDS..08/07/19 ATTN...WFO...OAX...LBF...GID...FSD...UNR... STATUS REPORT FOR WS 557 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-011-017-041-071-077-089-093-115-125-149-163-175-183- 070740- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOONE BROWN CUSTER GARFIELD GREELEY HOLT HOWARD LOUP NANCE ROCK SHERMAN VALLEY WHEELER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0557 Status Updates
STATUS REPORT ON WW 557 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNW ANW TO 20 NE ANW TO 25 NNW ONL TO 20 NNE ONL TO 45 W OFK TO 20 WNW OLU. ..EDWARDS..08/07/19 ATTN...WFO...OAX...LBF...GID...FSD...UNR... STATUS REPORT FOR WS 557 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-011-017-041-071-077-089-093-115-125-149-163-175-183- 070740- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOONE BROWN CUSTER GARFIELD GREELEY HOLT HOWARD LOUP NANCE ROCK SHERMAN VALLEY WHEELER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0557 Status Updates
STATUS REPORT ON WW 557 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNW ANW TO 20 NE ANW TO 25 NNW ONL TO 20 NNE ONL TO 45 W OFK TO 20 WNW OLU. ..EDWARDS..08/07/19 ATTN...WFO...OAX...LBF...GID...FSD...UNR... STATUS REPORT FOR WS 557 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-011-017-041-071-077-089-093-115-125-149-163-175-183- 070740- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOONE BROWN CUSTER GARFIELD GREELEY HOLT HOWARD LOUP NANCE ROCK SHERMAN VALLEY WHEELER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 557 SEVERE TSTM NE SD 070120Z - 070800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 557 NWS Storm Prediction Center Norman OK 820 PM CDT Tue Aug 6 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Parts of north central and central Nebraska Parts of south central and southeast South Dakota * Effective this Tuesday night and Wednesday morning from 820 PM until 300 AM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Clusters of severe storms, including some supercells, will continue to spread south-southeastward from South Dakota into Nebraska overnight, with additional storm development also possible. The storm environment will favor large hail and damaging gusts as the primary severe threats through the early morning hours. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 45 miles north of Chamberlain SD to 55 miles south southeast of Burwell NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 555...WW 556... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 32030. ...Thompson Read more

MD 1658 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN/CENTRAL AL AND NORTHEASTERN MS
Mesoscale Discussion 1658 NWS Storm Prediction Center Norman OK 0123 AM CDT Wed Aug 07 2019 Areas affected...portions of northern/central AL and northeastern MS Concerning...Severe potential...Watch unlikely Valid 070623Z - 070900Z Probability of Watch Issuance...20 percent SUMMARY...Isolated damaging gusts, some near severe limits, may occur with a southeastward-moving band of thunderstorms during the next few hours. A watch is not currently expected. DISCUSSION...A loosely organized, multicellular thunderstorm cluster was evident at 06Z crossing from southern TN into portions of northeastern MS and northern AL along an instability gradient. The thermodynamic environment was characterized by rich low-level moisture -- manifest in low/mid 70s F surface dew points, though modified 00Z BMX RAOB and RAP soundings indicate only about 1.3- 1.5-inch total PW thanks to a dry layer above the surface. Nocturnal stabilization, and the presence of that dry layer, has offsetting effects: 1. Rendering MUCAPE unrepresentative on the high side while minimizing MLCAPE, with the latter ranging from around 1000 J/kg in central MS to only around 250 J/kg in northeastern AL, and 2. Support evaporative cooling and downdraft acceleration in that layer just above the surface. It is uncertain how much such downward parcel acceleration can overcome a gradually cooling near-surface layer (with associated increase in static stability) to render severe wind at the surface, but damaging gusts cannot be ruled out in the most intense cores. Kinematically, low-level flow should remain very weak, with west-northwesterly to northwesterly 850-mb winds minimizing storm-relative flow in the inflow layer. Regardless, the forward-propagational component of convective motion should be sufficient to sustain some inflow for a few more hours, amidst about 30-40 kt ambient effective-shear magnitudes. While a severe (50+ kt) gust cannot be ruled out, the potential currently appears too isolated and marginal for a watch. ..Edwards/Broyles.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BMX...HUN...MEG...JAN... LAT...LON 34848893 34838883 34788818 34788747 34628674 33718643 33168655 32948804 33218903 34908918 34848893 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IN INTO OH...THE NORTHERN WV PANHANDLE...WESTERN PA AND FAR WESTERN NY... ...SUMMARY... Strong to severe thunderstorms capable of large hail and locally damaging wind gusts are expected Thursday afternoon and evening across portions of the Midwest from Indiana to western Pennsylvania and far western New York. ...Ohio Valley/Lower Great Lakes Vicinity... An upper trough over the upper Great Lakes will pivot eastward across the Midwest on Thursday, spreading strong northwesterly deep-layer flow across the region. At the surface, west/southwesterly low-level winds will transport mid to upper 60s F dewpoints eastward across the Ohio Valley toward the lower Great Lakes ahead of a southeastward-advancing cold front. Strong heating in this corridor of richer boundary-layer moisture will result in moderate instability (1500-2500 J/kg MLCAPE) in the presence of 30-40 kt effective shear. Convection may be ongoing Thursday morning across southwest MI and should increase and intensify by early afternoon across OH/IN, shifting southeast toward western NY/PA through the afternoon/evening. Vertical shear will support sustained cells with rotating updrafts and perhaps even some supercell structures, and long, straight forecast hodographs indicate a threat for large hail. While midlevel lapse rates are modest (around 6.5 C/km), CAPE/shear parameters should compensate some and most intense cells will be capable of large hail. 0-3 km lapse rates are also modest, but relatively fast storm motion could result in locally strong wind gusts. The severe threat becomes more uncertain/conditional with westward extent into west-central IN and IL. While steeper lapse rates and stronger instability will be in place with similar shear profiles as those to the east, forecast soundings indicate this area may be under the influence of midlevel subsidence. This scenario would suppress convection across the area. However, if storms do develop further west, thermodynamic and kinematic parameters certainly would support a severe threat. ...Portions of the High Plains into KS/OK... The upper ridge will shift east on Thursday, becoming oriented over the northern High Plains southward to western TX during the second half of the period. This will keep the region on the southern fringes of stronger northwesterly deep-layer flow. At the surface, a warm front will stall near the OK/KS border and be a focus for potential heavy rain. Some severe threat could develop in the vicinity of the warm front, but several rounds of convection between now and then is resulting in too much uncertainty in evolution of the boundary layer across that area. What does seem more likely is at least a low-end severe threat across parts of the High Plains from northeast NM into eastern CO/WY, southwest SD and perhaps as far east as the NE Panhandle far western KS. Southeasterly upslope low-level flow will transport low 50s dewpoints westward along the I-25 corridor, with low to mid 60s further east. Strong heating will result in storm development over higher terrain by early afternoon. Midlevel flow will be somewhat weak, but effective shear greater than 40 kt and MLCAPE as high as 1500 J/kg should support sporadic strong cells capable of hail and perhaps locally damaging gusts during the afternoon and early evening. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/07/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IN INTO OH...THE NORTHERN WV PANHANDLE...WESTERN PA AND FAR WESTERN NY... ...SUMMARY... Strong to severe thunderstorms capable of large hail and locally damaging wind gusts are expected Thursday afternoon and evening across portions of the Midwest from Indiana to western Pennsylvania and far western New York. ...Ohio Valley/Lower Great Lakes Vicinity... An upper trough over the upper Great Lakes will pivot eastward across the Midwest on Thursday, spreading strong northwesterly deep-layer flow across the region. At the surface, west/southwesterly low-level winds will transport mid to upper 60s F dewpoints eastward across the Ohio Valley toward the lower Great Lakes ahead of a southeastward-advancing cold front. Strong heating in this corridor of richer boundary-layer moisture will result in moderate instability (1500-2500 J/kg MLCAPE) in the presence of 30-40 kt effective shear. Convection may be ongoing Thursday morning across southwest MI and should increase and intensify by early afternoon across OH/IN, shifting southeast toward western NY/PA through the afternoon/evening. Vertical shear will support sustained cells with rotating updrafts and perhaps even some supercell structures, and long, straight forecast hodographs indicate a threat for large hail. While midlevel lapse rates are modest (around 6.5 C/km), CAPE/shear parameters should compensate some and most intense cells will be capable of large hail. 0-3 km lapse rates are also modest, but relatively fast storm motion could result in locally strong wind gusts. The severe threat becomes more uncertain/conditional with westward extent into west-central IN and IL. While steeper lapse rates and stronger instability will be in place with similar shear profiles as those to the east, forecast soundings indicate this area may be under the influence of midlevel subsidence. This scenario would suppress convection across the area. However, if storms do develop further west, thermodynamic and kinematic parameters certainly would support a severe threat. ...Portions of the High Plains into KS/OK... The upper ridge will shift east on Thursday, becoming oriented over the northern High Plains southward to western TX during the second half of the period. This will keep the region on the southern fringes of stronger northwesterly deep-layer flow. At the surface, a warm front will stall near the OK/KS border and be a focus for potential heavy rain. Some severe threat could develop in the vicinity of the warm front, but several rounds of convection between now and then is resulting in too much uncertainty in evolution of the boundary layer across that area. What does seem more likely is at least a low-end severe threat across parts of the High Plains from northeast NM into eastern CO/WY, southwest SD and perhaps as far east as the NE Panhandle far western KS. Southeasterly upslope low-level flow will transport low 50s dewpoints westward along the I-25 corridor, with low to mid 60s further east. Strong heating will result in storm development over higher terrain by early afternoon. Midlevel flow will be somewhat weak, but effective shear greater than 40 kt and MLCAPE as high as 1500 J/kg should support sporadic strong cells capable of hail and perhaps locally damaging gusts during the afternoon and early evening. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/07/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IN INTO OH...THE NORTHERN WV PANHANDLE...WESTERN PA AND FAR WESTERN NY... ...SUMMARY... Strong to severe thunderstorms capable of large hail and locally damaging wind gusts are expected Thursday afternoon and evening across portions of the Midwest from Indiana to western Pennsylvania and far western New York. ...Ohio Valley/Lower Great Lakes Vicinity... An upper trough over the upper Great Lakes will pivot eastward across the Midwest on Thursday, spreading strong northwesterly deep-layer flow across the region. At the surface, west/southwesterly low-level winds will transport mid to upper 60s F dewpoints eastward across the Ohio Valley toward the lower Great Lakes ahead of a southeastward-advancing cold front. Strong heating in this corridor of richer boundary-layer moisture will result in moderate instability (1500-2500 J/kg MLCAPE) in the presence of 30-40 kt effective shear. Convection may be ongoing Thursday morning across southwest MI and should increase and intensify by early afternoon across OH/IN, shifting southeast toward western NY/PA through the afternoon/evening. Vertical shear will support sustained cells with rotating updrafts and perhaps even some supercell structures, and long, straight forecast hodographs indicate a threat for large hail. While midlevel lapse rates are modest (around 6.5 C/km), CAPE/shear parameters should compensate some and most intense cells will be capable of large hail. 0-3 km lapse rates are also modest, but relatively fast storm motion could result in locally strong wind gusts. The severe threat becomes more uncertain/conditional with westward extent into west-central IN and IL. While steeper lapse rates and stronger instability will be in place with similar shear profiles as those to the east, forecast soundings indicate this area may be under the influence of midlevel subsidence. This scenario would suppress convection across the area. However, if storms do develop further west, thermodynamic and kinematic parameters certainly would support a severe threat. ...Portions of the High Plains into KS/OK... The upper ridge will shift east on Thursday, becoming oriented over the northern High Plains southward to western TX during the second half of the period. This will keep the region on the southern fringes of stronger northwesterly deep-layer flow. At the surface, a warm front will stall near the OK/KS border and be a focus for potential heavy rain. Some severe threat could develop in the vicinity of the warm front, but several rounds of convection between now and then is resulting in too much uncertainty in evolution of the boundary layer across that area. What does seem more likely is at least a low-end severe threat across parts of the High Plains from northeast NM into eastern CO/WY, southwest SD and perhaps as far east as the NE Panhandle far western KS. Southeasterly upslope low-level flow will transport low 50s dewpoints westward along the I-25 corridor, with low to mid 60s further east. Strong heating will result in storm development over higher terrain by early afternoon. Midlevel flow will be somewhat weak, but effective shear greater than 40 kt and MLCAPE as high as 1500 J/kg should support sporadic strong cells capable of hail and perhaps locally damaging gusts during the afternoon and early evening. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/07/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IN INTO OH...THE NORTHERN WV PANHANDLE...WESTERN PA AND FAR WESTERN NY... ...SUMMARY... Strong to severe thunderstorms capable of large hail and locally damaging wind gusts are expected Thursday afternoon and evening across portions of the Midwest from Indiana to western Pennsylvania and far western New York. ...Ohio Valley/Lower Great Lakes Vicinity... An upper trough over the upper Great Lakes will pivot eastward across the Midwest on Thursday, spreading strong northwesterly deep-layer flow across the region. At the surface, west/southwesterly low-level winds will transport mid to upper 60s F dewpoints eastward across the Ohio Valley toward the lower Great Lakes ahead of a southeastward-advancing cold front. Strong heating in this corridor of richer boundary-layer moisture will result in moderate instability (1500-2500 J/kg MLCAPE) in the presence of 30-40 kt effective shear. Convection may be ongoing Thursday morning across southwest MI and should increase and intensify by early afternoon across OH/IN, shifting southeast toward western NY/PA through the afternoon/evening. Vertical shear will support sustained cells with rotating updrafts and perhaps even some supercell structures, and long, straight forecast hodographs indicate a threat for large hail. While midlevel lapse rates are modest (around 6.5 C/km), CAPE/shear parameters should compensate some and most intense cells will be capable of large hail. 0-3 km lapse rates are also modest, but relatively fast storm motion could result in locally strong wind gusts. The severe threat becomes more uncertain/conditional with westward extent into west-central IN and IL. While steeper lapse rates and stronger instability will be in place with similar shear profiles as those to the east, forecast soundings indicate this area may be under the influence of midlevel subsidence. This scenario would suppress convection across the area. However, if storms do develop further west, thermodynamic and kinematic parameters certainly would support a severe threat. ...Portions of the High Plains into KS/OK... The upper ridge will shift east on Thursday, becoming oriented over the northern High Plains southward to western TX during the second half of the period. This will keep the region on the southern fringes of stronger northwesterly deep-layer flow. At the surface, a warm front will stall near the OK/KS border and be a focus for potential heavy rain. Some severe threat could develop in the vicinity of the warm front, but several rounds of convection between now and then is resulting in too much uncertainty in evolution of the boundary layer across that area. What does seem more likely is at least a low-end severe threat across parts of the High Plains from northeast NM into eastern CO/WY, southwest SD and perhaps as far east as the NE Panhandle far western KS. Southeasterly upslope low-level flow will transport low 50s dewpoints westward along the I-25 corridor, with low to mid 60s further east. Strong heating will result in storm development over higher terrain by early afternoon. Midlevel flow will be somewhat weak, but effective shear greater than 40 kt and MLCAPE as high as 1500 J/kg should support sporadic strong cells capable of hail and perhaps locally damaging gusts during the afternoon and early evening. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/07/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Aug 07 2019 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT ACROSS PARTS OF THE MID ATLANTIC COAST STATES INTO WESTERN NEW ENGLAND...ACROSS PARTS OF THE UPPER MIDWEST...AND ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms are possible today into tonight across parts of the Mid Atlantic Coast states into portions of western New England, across parts of the Upper Midwest, and across parts of the central Plains. These will pose are risk for large hail and potentially damaging wind gusts. ...Synopsis... Blocking appears likely to remain prominent across the mid-latitude eastern Pacific through this period, with a long fetch of northwesterly mid/upper flow downstream, across Alaska and the Yukon Territory through the central Canadian/U.S. border vicinity. On the leading edge of this regime, a large short wave trough and embedded mid-level closed low are forecast to continue digging southeastward, across northern Ontario and the upper Great Lakes region. Models indicate that this will be accompanied by another notable cold front, which is forecast to advance southeastward across much of the northern Plains, Upper Midwest and Great Lakes region by daybreak Thursday. This will be preceded by another cold front, associated with large-scale troughing within a weaker branch of westerlies at lower latitudes, which is expected to continue gradually shifting east of the Mississippi Valley through the Atlantic Seaboard. The lead front may progress southeastward into the Mid Atlantic coast, and more slowly southward through the Tennessee Valley/Ozark Plateau region. It may be reinforced by convective outflow, before stalling across eastern portions of the central Plains. A mid/upper subtropical high, centered over the Four Corners states, may begin to weaken, but large-scale ridging is expected to remain a prominent influence across much of the Intermountain West/Rockies and southern Plains. Subtle short wave perturbations progressing around the periphery of the ridging, into the southern periphery of the broad troughing over the Tennessee Valley/eastern Gulf states, may provide the support and focus for organizing clusters of thunderstorms today through tonight, in the presence of moderate to strong instability. However, the predictability of these features remains relatively low, resulting in only marginal severe probabilities, except across eastern portions of the central Plains. Otherwise, forcing for ascent associated with the more prominent short waves, and destabilization ahead of their associated cold fronts, appear to provide more certain support for severe thunderstorm development. ...Mid Atlantic Coast states into western New England... Although the plume of tropical moisture has advected ahead an initial short wave trough, well east of the Atlantic Seaboard (aside from the southern Florida Peninsula), low-level moisture appears to remain sufficient to support moderate CAPE along pre-frontal surface troughing near/east of the Appalachians. As destabilization commences with daytime heating, 20-40 kt south/southwesterly flow in the 850-500 mb layer is expected to overspread the region and contribute to at least marginally sufficient shear to organize convection and support a risk for potentially damaging wind gusts and some hail. This will be aided by forcing for ascent associated with several smaller-scale perturbations. This may include one mid-level cyclonic vorticity maximum and associated developing area of low pressure, that could contribute to at least low probabilities for a tornado or two across parts of Upstate New York into the Hudson/Champlain Valleys. ...Upper Midwest... Mid-level cooling and forcing for ascent in the exit region of a 50+ kt mid-level jet propagating around the southern periphery of the vigorous digging upper trough will provide support for thunderstorm development late this afternoon or evening. With models generally suggest CAPE at least on the order of 1000-2000 J/kg across parts of eastern Minnesota into Wisconsin and portions of upper Michigan, the environment is expected to become conducive to isolated supercells and small organizing storm clusters posing a risk for severe hail and locally strong surface gusts. ...Eastern portions of the central Plains... Uncertainty exists concerning the extent and intensity of a possible early period cluster of storms now developing across parts of central/eastern Nebraska. However, models generally indicate that an associated outflow boundary/zone of stronger differential surface heating will provide a potential focus for organized severe thunderstorm development late this afternoon into tonight. Large CAPE along and south of the boundary, coupled with favorable shear beneath at least moderate northwest mid-level flow, may become supportive of isolated supercells by early this evening. The nose of a strengthening southerly low-level jet (including 30-40+ kt at 850 mb) may provide the focus for an upscale growing and organizing convective system across northeastern Kansas late this evening into the overnight hours, which could pose a risk for strong surface gusts. ..Kerr/Dean.. 08/07/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Aug 07 2019 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT ACROSS PARTS OF THE MID ATLANTIC COAST STATES INTO WESTERN NEW ENGLAND...ACROSS PARTS OF THE UPPER MIDWEST...AND ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms are possible today into tonight across parts of the Mid Atlantic Coast states into portions of western New England, across parts of the Upper Midwest, and across parts of the central Plains. These will pose are risk for large hail and potentially damaging wind gusts. ...Synopsis... Blocking appears likely to remain prominent across the mid-latitude eastern Pacific through this period, with a long fetch of northwesterly mid/upper flow downstream, across Alaska and the Yukon Territory through the central Canadian/U.S. border vicinity. On the leading edge of this regime, a large short wave trough and embedded mid-level closed low are forecast to continue digging southeastward, across northern Ontario and the upper Great Lakes region. Models indicate that this will be accompanied by another notable cold front, which is forecast to advance southeastward across much of the northern Plains, Upper Midwest and Great Lakes region by daybreak Thursday. This will be preceded by another cold front, associated with large-scale troughing within a weaker branch of westerlies at lower latitudes, which is expected to continue gradually shifting east of the Mississippi Valley through the Atlantic Seaboard. The lead front may progress southeastward into the Mid Atlantic coast, and more slowly southward through the Tennessee Valley/Ozark Plateau region. It may be reinforced by convective outflow, before stalling across eastern portions of the central Plains. A mid/upper subtropical high, centered over the Four Corners states, may begin to weaken, but large-scale ridging is expected to remain a prominent influence across much of the Intermountain West/Rockies and southern Plains. Subtle short wave perturbations progressing around the periphery of the ridging, into the southern periphery of the broad troughing over the Tennessee Valley/eastern Gulf states, may provide the support and focus for organizing clusters of thunderstorms today through tonight, in the presence of moderate to strong instability. However, the predictability of these features remains relatively low, resulting in only marginal severe probabilities, except across eastern portions of the central Plains. Otherwise, forcing for ascent associated with the more prominent short waves, and destabilization ahead of their associated cold fronts, appear to provide more certain support for severe thunderstorm development. ...Mid Atlantic Coast states into western New England... Although the plume of tropical moisture has advected ahead an initial short wave trough, well east of the Atlantic Seaboard (aside from the southern Florida Peninsula), low-level moisture appears to remain sufficient to support moderate CAPE along pre-frontal surface troughing near/east of the Appalachians. As destabilization commences with daytime heating, 20-40 kt south/southwesterly flow in the 850-500 mb layer is expected to overspread the region and contribute to at least marginally sufficient shear to organize convection and support a risk for potentially damaging wind gusts and some hail. This will be aided by forcing for ascent associated with several smaller-scale perturbations. This may include one mid-level cyclonic vorticity maximum and associated developing area of low pressure, that could contribute to at least low probabilities for a tornado or two across parts of Upstate New York into the Hudson/Champlain Valleys. ...Upper Midwest... Mid-level cooling and forcing for ascent in the exit region of a 50+ kt mid-level jet propagating around the southern periphery of the vigorous digging upper trough will provide support for thunderstorm development late this afternoon or evening. With models generally suggest CAPE at least on the order of 1000-2000 J/kg across parts of eastern Minnesota into Wisconsin and portions of upper Michigan, the environment is expected to become conducive to isolated supercells and small organizing storm clusters posing a risk for severe hail and locally strong surface gusts. ...Eastern portions of the central Plains... Uncertainty exists concerning the extent and intensity of a possible early period cluster of storms now developing across parts of central/eastern Nebraska. However, models generally indicate that an associated outflow boundary/zone of stronger differential surface heating will provide a potential focus for organized severe thunderstorm development late this afternoon into tonight. Large CAPE along and south of the boundary, coupled with favorable shear beneath at least moderate northwest mid-level flow, may become supportive of isolated supercells by early this evening. The nose of a strengthening southerly low-level jet (including 30-40+ kt at 850 mb) may provide the focus for an upscale growing and organizing convective system across northeastern Kansas late this evening into the overnight hours, which could pose a risk for strong surface gusts. ..Kerr/Dean.. 08/07/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Aug 07 2019 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT ACROSS PARTS OF THE MID ATLANTIC COAST STATES INTO WESTERN NEW ENGLAND...ACROSS PARTS OF THE UPPER MIDWEST...AND ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms are possible today into tonight across parts of the Mid Atlantic Coast states into portions of western New England, across parts of the Upper Midwest, and across parts of the central Plains. These will pose are risk for large hail and potentially damaging wind gusts. ...Synopsis... Blocking appears likely to remain prominent across the mid-latitude eastern Pacific through this period, with a long fetch of northwesterly mid/upper flow downstream, across Alaska and the Yukon Territory through the central Canadian/U.S. border vicinity. On the leading edge of this regime, a large short wave trough and embedded mid-level closed low are forecast to continue digging southeastward, across northern Ontario and the upper Great Lakes region. Models indicate that this will be accompanied by another notable cold front, which is forecast to advance southeastward across much of the northern Plains, Upper Midwest and Great Lakes region by daybreak Thursday. This will be preceded by another cold front, associated with large-scale troughing within a weaker branch of westerlies at lower latitudes, which is expected to continue gradually shifting east of the Mississippi Valley through the Atlantic Seaboard. The lead front may progress southeastward into the Mid Atlantic coast, and more slowly southward through the Tennessee Valley/Ozark Plateau region. It may be reinforced by convective outflow, before stalling across eastern portions of the central Plains. A mid/upper subtropical high, centered over the Four Corners states, may begin to weaken, but large-scale ridging is expected to remain a prominent influence across much of the Intermountain West/Rockies and southern Plains. Subtle short wave perturbations progressing around the periphery of the ridging, into the southern periphery of the broad troughing over the Tennessee Valley/eastern Gulf states, may provide the support and focus for organizing clusters of thunderstorms today through tonight, in the presence of moderate to strong instability. However, the predictability of these features remains relatively low, resulting in only marginal severe probabilities, except across eastern portions of the central Plains. Otherwise, forcing for ascent associated with the more prominent short waves, and destabilization ahead of their associated cold fronts, appear to provide more certain support for severe thunderstorm development. ...Mid Atlantic Coast states into western New England... Although the plume of tropical moisture has advected ahead an initial short wave trough, well east of the Atlantic Seaboard (aside from the southern Florida Peninsula), low-level moisture appears to remain sufficient to support moderate CAPE along pre-frontal surface troughing near/east of the Appalachians. As destabilization commences with daytime heating, 20-40 kt south/southwesterly flow in the 850-500 mb layer is expected to overspread the region and contribute to at least marginally sufficient shear to organize convection and support a risk for potentially damaging wind gusts and some hail. This will be aided by forcing for ascent associated with several smaller-scale perturbations. This may include one mid-level cyclonic vorticity maximum and associated developing area of low pressure, that could contribute to at least low probabilities for a tornado or two across parts of Upstate New York into the Hudson/Champlain Valleys. ...Upper Midwest... Mid-level cooling and forcing for ascent in the exit region of a 50+ kt mid-level jet propagating around the southern periphery of the vigorous digging upper trough will provide support for thunderstorm development late this afternoon or evening. With models generally suggest CAPE at least on the order of 1000-2000 J/kg across parts of eastern Minnesota into Wisconsin and portions of upper Michigan, the environment is expected to become conducive to isolated supercells and small organizing storm clusters posing a risk for severe hail and locally strong surface gusts. ...Eastern portions of the central Plains... Uncertainty exists concerning the extent and intensity of a possible early period cluster of storms now developing across parts of central/eastern Nebraska. However, models generally indicate that an associated outflow boundary/zone of stronger differential surface heating will provide a potential focus for organized severe thunderstorm development late this afternoon into tonight. Large CAPE along and south of the boundary, coupled with favorable shear beneath at least moderate northwest mid-level flow, may become supportive of isolated supercells by early this evening. The nose of a strengthening southerly low-level jet (including 30-40+ kt at 850 mb) may provide the focus for an upscale growing and organizing convective system across northeastern Kansas late this evening into the overnight hours, which could pose a risk for strong surface gusts. ..Kerr/Dean.. 08/07/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Aug 07 2019 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT ACROSS PARTS OF THE MID ATLANTIC COAST STATES INTO WESTERN NEW ENGLAND...ACROSS PARTS OF THE UPPER MIDWEST...AND ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms are possible today into tonight across parts of the Mid Atlantic Coast states into portions of western New England, across parts of the Upper Midwest, and across parts of the central Plains. These will pose are risk for large hail and potentially damaging wind gusts. ...Synopsis... Blocking appears likely to remain prominent across the mid-latitude eastern Pacific through this period, with a long fetch of northwesterly mid/upper flow downstream, across Alaska and the Yukon Territory through the central Canadian/U.S. border vicinity. On the leading edge of this regime, a large short wave trough and embedded mid-level closed low are forecast to continue digging southeastward, across northern Ontario and the upper Great Lakes region. Models indicate that this will be accompanied by another notable cold front, which is forecast to advance southeastward across much of the northern Plains, Upper Midwest and Great Lakes region by daybreak Thursday. This will be preceded by another cold front, associated with large-scale troughing within a weaker branch of westerlies at lower latitudes, which is expected to continue gradually shifting east of the Mississippi Valley through the Atlantic Seaboard. The lead front may progress southeastward into the Mid Atlantic coast, and more slowly southward through the Tennessee Valley/Ozark Plateau region. It may be reinforced by convective outflow, before stalling across eastern portions of the central Plains. A mid/upper subtropical high, centered over the Four Corners states, may begin to weaken, but large-scale ridging is expected to remain a prominent influence across much of the Intermountain West/Rockies and southern Plains. Subtle short wave perturbations progressing around the periphery of the ridging, into the southern periphery of the broad troughing over the Tennessee Valley/eastern Gulf states, may provide the support and focus for organizing clusters of thunderstorms today through tonight, in the presence of moderate to strong instability. However, the predictability of these features remains relatively low, resulting in only marginal severe probabilities, except across eastern portions of the central Plains. Otherwise, forcing for ascent associated with the more prominent short waves, and destabilization ahead of their associated cold fronts, appear to provide more certain support for severe thunderstorm development. ...Mid Atlantic Coast states into western New England... Although the plume of tropical moisture has advected ahead an initial short wave trough, well east of the Atlantic Seaboard (aside from the southern Florida Peninsula), low-level moisture appears to remain sufficient to support moderate CAPE along pre-frontal surface troughing near/east of the Appalachians. As destabilization commences with daytime heating, 20-40 kt south/southwesterly flow in the 850-500 mb layer is expected to overspread the region and contribute to at least marginally sufficient shear to organize convection and support a risk for potentially damaging wind gusts and some hail. This will be aided by forcing for ascent associated with several smaller-scale perturbations. This may include one mid-level cyclonic vorticity maximum and associated developing area of low pressure, that could contribute to at least low probabilities for a tornado or two across parts of Upstate New York into the Hudson/Champlain Valleys. ...Upper Midwest... Mid-level cooling and forcing for ascent in the exit region of a 50+ kt mid-level jet propagating around the southern periphery of the vigorous digging upper trough will provide support for thunderstorm development late this afternoon or evening. With models generally suggest CAPE at least on the order of 1000-2000 J/kg across parts of eastern Minnesota into Wisconsin and portions of upper Michigan, the environment is expected to become conducive to isolated supercells and small organizing storm clusters posing a risk for severe hail and locally strong surface gusts. ...Eastern portions of the central Plains... Uncertainty exists concerning the extent and intensity of a possible early period cluster of storms now developing across parts of central/eastern Nebraska. However, models generally indicate that an associated outflow boundary/zone of stronger differential surface heating will provide a potential focus for organized severe thunderstorm development late this afternoon into tonight. Large CAPE along and south of the boundary, coupled with favorable shear beneath at least moderate northwest mid-level flow, may become supportive of isolated supercells by early this evening. The nose of a strengthening southerly low-level jet (including 30-40+ kt at 850 mb) may provide the focus for an upscale growing and organizing convective system across northeastern Kansas late this evening into the overnight hours, which could pose a risk for strong surface gusts. ..Kerr/Dean.. 08/07/2019 Read more

WW 0557 Status Updates
STATUS REPORT ON WW 557 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 E VTN TO 35 NNW ONL TO 30 NE ONL TO 20 E ONL TO 20 NW OFK. FOR ADDITIONAL INFORMATION SEE SPC MESOSCALE DISCUSSION 1657. ..EDWARDS..08/07/19 ATTN...WFO...OAX...LBF...GID...FSD...UNR... STATUS REPORT FOR WS 557 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC003-009-011-015-017-041-071-077-089-093-103-115-125-149-163- 175-183-070640- NE . NEBRASKA COUNTIES INCLUDED ARE ANTELOPE BLAINE BOONE BOYD BROWN CUSTER GARFIELD GREELEY HOLT HOWARD KEYA PAHA LOUP NANCE ROCK SHERMAN VALLEY WHEELER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

MD 1657 CONCERNING SEVERE THUNDERSTORM WATCH 557... FOR SOUTH-CENTRAL SOUTH DAKOTA INTO CENTRAL NEBRASKA
Mesoscale Discussion 1657 NWS Storm Prediction Center Norman OK 1024 PM CDT Tue Aug 06 2019 Areas affected...south-central South Dakota into central Nebraska Concerning...Severe Thunderstorm Watch 557... Valid 070324Z - 070530Z The severe weather threat for Severe Thunderstorm Watch 557 continues. SUMMARY...A corridor of very large hail and damaging wind potential stretches from south-central South Dakota into central Nebraska. DISCUSSION...A cluster of supercells continues to travel south-southeastward along the MO River in southern SD, within a weak surface trough and along an instability gradient where modest warm advection exists at 850 mb. West of the primary cluster, several smaller cells were affecting far northern NE, with indications of marginally severe hail. The 00Z LBF sounding shows strong instability along with a long, straight hodograph and minimal capping potential given mid to upper 60s F dewpoints. As 850 mb winds remain out of the southwest, the cluster of supercells is likely to persist for several hours, with damaging hail and wind possible into central NE. ..Jewell.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...OAX...GID...LBF...UNR... LAT...LON 43269970 43459943 43519904 43179879 42699852 42029823 41349801 41019816 40899860 40909932 41239963 41939963 42639965 43269970 Read more

WW 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more