Severe Storms

MD 1673 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR KANSAS
Mesoscale Discussion 1673 NWS Storm Prediction Center Norman OK 0101 AM CDT Thu Aug 08 2019 Areas affected...Kansas Concerning...Severe potential...Watch unlikely Valid 080601Z - 080830Z Probability of Watch Issuance...20 percent SUMMARY...A potential for hail and marginally severe wind gusts will exist tonight along a west-northwest to east-southeast corridor from northwest to southeast Kansas. Although weather watch issuance appears unlikely, the situation will continue to be monitored. DISCUSSION...The latest surface analysis shows a quasi-stationary front located from southwest Kansas into northern Oklahoma. An axis of moderate instability is analyzed by the RAP to the north of the front where MLCAPE is peaked in the 2,000 to 2,500 J/kg range. A cluster of strong thunderstorms is located near the Colorado-Kansas line just to the west of the strongest instability. These storms will continue to move eastward into the instability maximum over the next few hours helping to sustain updraft intensity. The Goodland WSR-88D VWP has about 30 kt of deep-layer shear. This combined with mid-level lapse rates around 8.0 C/km (evident on the RAP analysis) should support hail with the stronger updrafts. Marginally severe wind gusts will also be possible along the leading edge of the MCS. Further to the southeast across central and southeastern Kansas, MLCIN is substantially stronger. For this reason, the convection will remain be elevated in nature tonight. Even so, instability aloft and effective shear around 30 kt as estimated by the RAP and evident on regional WSR-88D VWPs should support a marginal hail threat. ..Broyles/Edwards.. 08/08/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SGF...TOP...ICT...GID...DDC...GLD... LAT...LON 39609890 38479607 37729509 37379493 37129508 37019540 37109607 37479677 38079797 38709973 38990092 39100165 39530190 39900150 40030056 39609890 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Thu Aug 08 2019 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL OREGON AND OVER WESTERN PORTIONS OF THE NORTHERN PLAINS... ...SUMMARY... Strong to severe thunderstorms are possible across portions of the northern Plains, as well as parts of central Oregon, Friday afternoon and evening. Large hail and damaging wind gusts will be the main concern. ...Central Oregon Vicinity... South/southwesterly deep layer flow will strengthen on Friday as an upper low pivots eastward over northern CA and OR. This deep-layer southerly flow will bring monsoonal moisture northward into the region, and surface dewpoints climbing into the low to mid 50s are possible. As heights fall and temperatures aloft cool, steep midlevel lapse rates will overspread the region, while strong surface heating results in scattered thunderstorm development during the afternoon. MLCAPE values will generally range from 500-1000 J/kg and effective shear greater than 35 kt is forecast. This should result in organized cells with rotating updrafts capable of large hail. Additionally, where deep boundary-layer mixing occurs, inverted-v sub-cloud thermodynamic profiles suggest cells also will pose a locally damaging wind threat. While not expected to be the main threat, guidance does suggest there could be a threat for a weak/brief tornado over central OR as a southeastward-progressing cold front moves toward the area after 00z. Any cells interacting with the boundary could result in lowered LCLs and enhanced SRH. However, this threat appears rather conditional and uncertain. ...Northern Plains into the Central High Plains Vicinity... The upper ridge will continue to be oriented from central TX north/northwest into MT on Friday. A couple of shortwave impulses are forecast to migrate through the ridge, providing support for strong to severe storms. The first, and stronger impulse, will eject eastward from the northern Rockies into the northern Plains. This should allow suppression of the upper ridge and associated midlevel capping through increased forcing for ascent, as boundary-layer moisture increases on strengthening low-level southeasterly flow. A weak low/surface trough will extend from eastern MT into western SD and thunderstorms are expected to develop during the afternoon along this boundary and shift east through the evening. Midlevel lapse rates will be unimpressive across the region due to warm temperatures aloft under the influence of the upper ridge, but strong heating and surface dewpoints in the 60s will result in moderate to strong instability (MLCAPE 2000-3500) in the presence of supercell vertical wind profiles. In fact, long, straight forecast hodographs indicate potential for storms dominated by hail production. Additionally, steep low-level lapse rates will support locally damaging winds as well. Some guidance suggest some upscale growth is possible as a 40 kt southerly low level jet develops during the evening across central NE/SD. If this occurs, a damaging wind threat could develop and probabilities may need adjusted in subsequent outlooks. More subtle monsoon-related impulses will float across the central Rockies and trigger thunderstorms over higher terrain during the afternoon. While deep-layer flow is weaker compared to further north, effective shear around 40 kt and steep lapse rates in the presence of 2000-3000 J/kg MLCAPE should maintain storms eastward over the adjacent High Plains. Isolated large hail and strong wind gusts will be the main concern with this convection. ...Ozarks into northern MS and western TN... Guidance continues to suggest that a likely MCV will progress east/southeast from the Ozarks into northern MS. A very moist and unstable downstream airmass will support strong to severe storms, with damaging winds being the main concern, aided by PW values greater than 2 inches and effective shear greater than 25 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/08/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Thu Aug 08 2019 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL OREGON AND OVER WESTERN PORTIONS OF THE NORTHERN PLAINS... ...SUMMARY... Strong to severe thunderstorms are possible across portions of the northern Plains, as well as parts of central Oregon, Friday afternoon and evening. Large hail and damaging wind gusts will be the main concern. ...Central Oregon Vicinity... South/southwesterly deep layer flow will strengthen on Friday as an upper low pivots eastward over northern CA and OR. This deep-layer southerly flow will bring monsoonal moisture northward into the region, and surface dewpoints climbing into the low to mid 50s are possible. As heights fall and temperatures aloft cool, steep midlevel lapse rates will overspread the region, while strong surface heating results in scattered thunderstorm development during the afternoon. MLCAPE values will generally range from 500-1000 J/kg and effective shear greater than 35 kt is forecast. This should result in organized cells with rotating updrafts capable of large hail. Additionally, where deep boundary-layer mixing occurs, inverted-v sub-cloud thermodynamic profiles suggest cells also will pose a locally damaging wind threat. While not expected to be the main threat, guidance does suggest there could be a threat for a weak/brief tornado over central OR as a southeastward-progressing cold front moves toward the area after 00z. Any cells interacting with the boundary could result in lowered LCLs and enhanced SRH. However, this threat appears rather conditional and uncertain. ...Northern Plains into the Central High Plains Vicinity... The upper ridge will continue to be oriented from central TX north/northwest into MT on Friday. A couple of shortwave impulses are forecast to migrate through the ridge, providing support for strong to severe storms. The first, and stronger impulse, will eject eastward from the northern Rockies into the northern Plains. This should allow suppression of the upper ridge and associated midlevel capping through increased forcing for ascent, as boundary-layer moisture increases on strengthening low-level southeasterly flow. A weak low/surface trough will extend from eastern MT into western SD and thunderstorms are expected to develop during the afternoon along this boundary and shift east through the evening. Midlevel lapse rates will be unimpressive across the region due to warm temperatures aloft under the influence of the upper ridge, but strong heating and surface dewpoints in the 60s will result in moderate to strong instability (MLCAPE 2000-3500) in the presence of supercell vertical wind profiles. In fact, long, straight forecast hodographs indicate potential for storms dominated by hail production. Additionally, steep low-level lapse rates will support locally damaging winds as well. Some guidance suggest some upscale growth is possible as a 40 kt southerly low level jet develops during the evening across central NE/SD. If this occurs, a damaging wind threat could develop and probabilities may need adjusted in subsequent outlooks. More subtle monsoon-related impulses will float across the central Rockies and trigger thunderstorms over higher terrain during the afternoon. While deep-layer flow is weaker compared to further north, effective shear around 40 kt and steep lapse rates in the presence of 2000-3000 J/kg MLCAPE should maintain storms eastward over the adjacent High Plains. Isolated large hail and strong wind gusts will be the main concern with this convection. ...Ozarks into northern MS and western TN... Guidance continues to suggest that a likely MCV will progress east/southeast from the Ozarks into northern MS. A very moist and unstable downstream airmass will support strong to severe storms, with damaging winds being the main concern, aided by PW values greater than 2 inches and effective shear greater than 25 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/08/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Thu Aug 08 2019 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL OREGON AND OVER WESTERN PORTIONS OF THE NORTHERN PLAINS... ...SUMMARY... Strong to severe thunderstorms are possible across portions of the northern Plains, as well as parts of central Oregon, Friday afternoon and evening. Large hail and damaging wind gusts will be the main concern. ...Central Oregon Vicinity... South/southwesterly deep layer flow will strengthen on Friday as an upper low pivots eastward over northern CA and OR. This deep-layer southerly flow will bring monsoonal moisture northward into the region, and surface dewpoints climbing into the low to mid 50s are possible. As heights fall and temperatures aloft cool, steep midlevel lapse rates will overspread the region, while strong surface heating results in scattered thunderstorm development during the afternoon. MLCAPE values will generally range from 500-1000 J/kg and effective shear greater than 35 kt is forecast. This should result in organized cells with rotating updrafts capable of large hail. Additionally, where deep boundary-layer mixing occurs, inverted-v sub-cloud thermodynamic profiles suggest cells also will pose a locally damaging wind threat. While not expected to be the main threat, guidance does suggest there could be a threat for a weak/brief tornado over central OR as a southeastward-progressing cold front moves toward the area after 00z. Any cells interacting with the boundary could result in lowered LCLs and enhanced SRH. However, this threat appears rather conditional and uncertain. ...Northern Plains into the Central High Plains Vicinity... The upper ridge will continue to be oriented from central TX north/northwest into MT on Friday. A couple of shortwave impulses are forecast to migrate through the ridge, providing support for strong to severe storms. The first, and stronger impulse, will eject eastward from the northern Rockies into the northern Plains. This should allow suppression of the upper ridge and associated midlevel capping through increased forcing for ascent, as boundary-layer moisture increases on strengthening low-level southeasterly flow. A weak low/surface trough will extend from eastern MT into western SD and thunderstorms are expected to develop during the afternoon along this boundary and shift east through the evening. Midlevel lapse rates will be unimpressive across the region due to warm temperatures aloft under the influence of the upper ridge, but strong heating and surface dewpoints in the 60s will result in moderate to strong instability (MLCAPE 2000-3500) in the presence of supercell vertical wind profiles. In fact, long, straight forecast hodographs indicate potential for storms dominated by hail production. Additionally, steep low-level lapse rates will support locally damaging winds as well. Some guidance suggest some upscale growth is possible as a 40 kt southerly low level jet develops during the evening across central NE/SD. If this occurs, a damaging wind threat could develop and probabilities may need adjusted in subsequent outlooks. More subtle monsoon-related impulses will float across the central Rockies and trigger thunderstorms over higher terrain during the afternoon. While deep-layer flow is weaker compared to further north, effective shear around 40 kt and steep lapse rates in the presence of 2000-3000 J/kg MLCAPE should maintain storms eastward over the adjacent High Plains. Isolated large hail and strong wind gusts will be the main concern with this convection. ...Ozarks into northern MS and western TN... Guidance continues to suggest that a likely MCV will progress east/southeast from the Ozarks into northern MS. A very moist and unstable downstream airmass will support strong to severe storms, with damaging winds being the main concern, aided by PW values greater than 2 inches and effective shear greater than 25 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/08/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Thu Aug 08 2019 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL OREGON AND OVER WESTERN PORTIONS OF THE NORTHERN PLAINS... ...SUMMARY... Strong to severe thunderstorms are possible across portions of the northern Plains, as well as parts of central Oregon, Friday afternoon and evening. Large hail and damaging wind gusts will be the main concern. ...Central Oregon Vicinity... South/southwesterly deep layer flow will strengthen on Friday as an upper low pivots eastward over northern CA and OR. This deep-layer southerly flow will bring monsoonal moisture northward into the region, and surface dewpoints climbing into the low to mid 50s are possible. As heights fall and temperatures aloft cool, steep midlevel lapse rates will overspread the region, while strong surface heating results in scattered thunderstorm development during the afternoon. MLCAPE values will generally range from 500-1000 J/kg and effective shear greater than 35 kt is forecast. This should result in organized cells with rotating updrafts capable of large hail. Additionally, where deep boundary-layer mixing occurs, inverted-v sub-cloud thermodynamic profiles suggest cells also will pose a locally damaging wind threat. While not expected to be the main threat, guidance does suggest there could be a threat for a weak/brief tornado over central OR as a southeastward-progressing cold front moves toward the area after 00z. Any cells interacting with the boundary could result in lowered LCLs and enhanced SRH. However, this threat appears rather conditional and uncertain. ...Northern Plains into the Central High Plains Vicinity... The upper ridge will continue to be oriented from central TX north/northwest into MT on Friday. A couple of shortwave impulses are forecast to migrate through the ridge, providing support for strong to severe storms. The first, and stronger impulse, will eject eastward from the northern Rockies into the northern Plains. This should allow suppression of the upper ridge and associated midlevel capping through increased forcing for ascent, as boundary-layer moisture increases on strengthening low-level southeasterly flow. A weak low/surface trough will extend from eastern MT into western SD and thunderstorms are expected to develop during the afternoon along this boundary and shift east through the evening. Midlevel lapse rates will be unimpressive across the region due to warm temperatures aloft under the influence of the upper ridge, but strong heating and surface dewpoints in the 60s will result in moderate to strong instability (MLCAPE 2000-3500) in the presence of supercell vertical wind profiles. In fact, long, straight forecast hodographs indicate potential for storms dominated by hail production. Additionally, steep low-level lapse rates will support locally damaging winds as well. Some guidance suggest some upscale growth is possible as a 40 kt southerly low level jet develops during the evening across central NE/SD. If this occurs, a damaging wind threat could develop and probabilities may need adjusted in subsequent outlooks. More subtle monsoon-related impulses will float across the central Rockies and trigger thunderstorms over higher terrain during the afternoon. While deep-layer flow is weaker compared to further north, effective shear around 40 kt and steep lapse rates in the presence of 2000-3000 J/kg MLCAPE should maintain storms eastward over the adjacent High Plains. Isolated large hail and strong wind gusts will be the main concern with this convection. ...Ozarks into northern MS and western TN... Guidance continues to suggest that a likely MCV will progress east/southeast from the Ozarks into northern MS. A very moist and unstable downstream airmass will support strong to severe storms, with damaging winds being the main concern, aided by PW values greater than 2 inches and effective shear greater than 25 kt. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 15% - Slight ..Leitman.. 08/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1148 PM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO VALLEY INTO CENTRAL NEW YORK AND PENNSYLVANIA... ...SUMMARY... Areas of hail and strong wind gusts are likely from the Ohio Valley eastward into central New York and Pennsylvania. Isolated severe hail is possible across parts of the High Plains. ...Synopsis... A broad area of cyclonic flow aloft will stretch from the upper MS Valley across the Great Lakes and the Northeast. A leading wave will move across New England during the day, with a secondary stronger wave moving into western NY and PA by 00Z. A cold front will progress across Lakes Ontario and Erie by 18Z, and will trail westward across central OH and IN. Ahead of the front, widespread low to mid 60s F dewpoints will exist beneath cool profiles aloft supporting strong to locally severe storms. To the west, an upper ridge will exist over the Rockies, with northwest flow over the Plains. A weak area of low pressure will exist over the TX Panhandle and western OK, with a stationary front extending eastward over northern OK or near the KS border. Ample low-level moisture will exist over the central Plains, with easterly winds north of the front aiding destabilization across the High Plains late in the day. ...OH Valley into the Northeast... An arcing line of storms is likely to develop by 18Z from western NY into northwest PA along the cold front, with additional development westward into OH and IN later in the afternoon. Northwest flow aloft will have a large component perpendicular to the boundary, with strong winds in the upper levels. This suggests the dominant storm mode will be cellular, with large hail likely. Little low-level shear/SRH suggests very low tornado risk, though damaging winds will be possible as storms form during peak heating with steep boundary layer lapse rates and 25-30 kt westerly 850 mb winds. ...Central and northern High Plains and northern Oklahoma into southern Kansas... Strong heating will occur beneath the upper ridge, while easterly surface winds maintain 50s dewpoints into eastern WY and CO. This will support afternoon development over the higher terrain, with activity slowly moving eastward through evening. Weak low-level winds beneath modest mid to upper flow will support a few slow-moving cells or propagating outflows, with marginal hail or wind will be possible. To the east into OK and KS, convection is likely to be ongoing early in the day north of the front from KS into western MO in a warm advection regime. Heating will occur upstream across TX and OK, resulting in areas of strong instability. New development is likely during the late afternoon and evening along the east-west front, with locally severe wind gusts or hail possible. ..Jewell/Cook.. 08/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1148 PM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO VALLEY INTO CENTRAL NEW YORK AND PENNSYLVANIA... ...SUMMARY... Areas of hail and strong wind gusts are likely from the Ohio Valley eastward into central New York and Pennsylvania. Isolated severe hail is possible across parts of the High Plains. ...Synopsis... A broad area of cyclonic flow aloft will stretch from the upper MS Valley across the Great Lakes and the Northeast. A leading wave will move across New England during the day, with a secondary stronger wave moving into western NY and PA by 00Z. A cold front will progress across Lakes Ontario and Erie by 18Z, and will trail westward across central OH and IN. Ahead of the front, widespread low to mid 60s F dewpoints will exist beneath cool profiles aloft supporting strong to locally severe storms. To the west, an upper ridge will exist over the Rockies, with northwest flow over the Plains. A weak area of low pressure will exist over the TX Panhandle and western OK, with a stationary front extending eastward over northern OK or near the KS border. Ample low-level moisture will exist over the central Plains, with easterly winds north of the front aiding destabilization across the High Plains late in the day. ...OH Valley into the Northeast... An arcing line of storms is likely to develop by 18Z from western NY into northwest PA along the cold front, with additional development westward into OH and IN later in the afternoon. Northwest flow aloft will have a large component perpendicular to the boundary, with strong winds in the upper levels. This suggests the dominant storm mode will be cellular, with large hail likely. Little low-level shear/SRH suggests very low tornado risk, though damaging winds will be possible as storms form during peak heating with steep boundary layer lapse rates and 25-30 kt westerly 850 mb winds. ...Central and northern High Plains and northern Oklahoma into southern Kansas... Strong heating will occur beneath the upper ridge, while easterly surface winds maintain 50s dewpoints into eastern WY and CO. This will support afternoon development over the higher terrain, with activity slowly moving eastward through evening. Weak low-level winds beneath modest mid to upper flow will support a few slow-moving cells or propagating outflows, with marginal hail or wind will be possible. To the east into OK and KS, convection is likely to be ongoing early in the day north of the front from KS into western MO in a warm advection regime. Heating will occur upstream across TX and OK, resulting in areas of strong instability. New development is likely during the late afternoon and evening along the east-west front, with locally severe wind gusts or hail possible. ..Jewell/Cook.. 08/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1148 PM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO VALLEY INTO CENTRAL NEW YORK AND PENNSYLVANIA... ...SUMMARY... Areas of hail and strong wind gusts are likely from the Ohio Valley eastward into central New York and Pennsylvania. Isolated severe hail is possible across parts of the High Plains. ...Synopsis... A broad area of cyclonic flow aloft will stretch from the upper MS Valley across the Great Lakes and the Northeast. A leading wave will move across New England during the day, with a secondary stronger wave moving into western NY and PA by 00Z. A cold front will progress across Lakes Ontario and Erie by 18Z, and will trail westward across central OH and IN. Ahead of the front, widespread low to mid 60s F dewpoints will exist beneath cool profiles aloft supporting strong to locally severe storms. To the west, an upper ridge will exist over the Rockies, with northwest flow over the Plains. A weak area of low pressure will exist over the TX Panhandle and western OK, with a stationary front extending eastward over northern OK or near the KS border. Ample low-level moisture will exist over the central Plains, with easterly winds north of the front aiding destabilization across the High Plains late in the day. ...OH Valley into the Northeast... An arcing line of storms is likely to develop by 18Z from western NY into northwest PA along the cold front, with additional development westward into OH and IN later in the afternoon. Northwest flow aloft will have a large component perpendicular to the boundary, with strong winds in the upper levels. This suggests the dominant storm mode will be cellular, with large hail likely. Little low-level shear/SRH suggests very low tornado risk, though damaging winds will be possible as storms form during peak heating with steep boundary layer lapse rates and 25-30 kt westerly 850 mb winds. ...Central and northern High Plains and northern Oklahoma into southern Kansas... Strong heating will occur beneath the upper ridge, while easterly surface winds maintain 50s dewpoints into eastern WY and CO. This will support afternoon development over the higher terrain, with activity slowly moving eastward through evening. Weak low-level winds beneath modest mid to upper flow will support a few slow-moving cells or propagating outflows, with marginal hail or wind will be possible. To the east into OK and KS, convection is likely to be ongoing early in the day north of the front from KS into western MO in a warm advection regime. Heating will occur upstream across TX and OK, resulting in areas of strong instability. New development is likely during the late afternoon and evening along the east-west front, with locally severe wind gusts or hail possible. ..Jewell/Cook.. 08/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1148 PM CDT Wed Aug 07 2019 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO VALLEY INTO CENTRAL NEW YORK AND PENNSYLVANIA... ...SUMMARY... Areas of hail and strong wind gusts are likely from the Ohio Valley eastward into central New York and Pennsylvania. Isolated severe hail is possible across parts of the High Plains. ...Synopsis... A broad area of cyclonic flow aloft will stretch from the upper MS Valley across the Great Lakes and the Northeast. A leading wave will move across New England during the day, with a secondary stronger wave moving into western NY and PA by 00Z. A cold front will progress across Lakes Ontario and Erie by 18Z, and will trail westward across central OH and IN. Ahead of the front, widespread low to mid 60s F dewpoints will exist beneath cool profiles aloft supporting strong to locally severe storms. To the west, an upper ridge will exist over the Rockies, with northwest flow over the Plains. A weak area of low pressure will exist over the TX Panhandle and western OK, with a stationary front extending eastward over northern OK or near the KS border. Ample low-level moisture will exist over the central Plains, with easterly winds north of the front aiding destabilization across the High Plains late in the day. ...OH Valley into the Northeast... An arcing line of storms is likely to develop by 18Z from western NY into northwest PA along the cold front, with additional development westward into OH and IN later in the afternoon. Northwest flow aloft will have a large component perpendicular to the boundary, with strong winds in the upper levels. This suggests the dominant storm mode will be cellular, with large hail likely. Little low-level shear/SRH suggests very low tornado risk, though damaging winds will be possible as storms form during peak heating with steep boundary layer lapse rates and 25-30 kt westerly 850 mb winds. ...Central and northern High Plains and northern Oklahoma into southern Kansas... Strong heating will occur beneath the upper ridge, while easterly surface winds maintain 50s dewpoints into eastern WY and CO. This will support afternoon development over the higher terrain, with activity slowly moving eastward through evening. Weak low-level winds beneath modest mid to upper flow will support a few slow-moving cells or propagating outflows, with marginal hail or wind will be possible. To the east into OK and KS, convection is likely to be ongoing early in the day north of the front from KS into western MO in a warm advection regime. Heating will occur upstream across TX and OK, resulting in areas of strong instability. New development is likely during the late afternoon and evening along the east-west front, with locally severe wind gusts or hail possible. ..Jewell/Cook.. 08/08/2019 Read more

MD 1672 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN SD...NORTHERN NE
Mesoscale Discussion 1672 NWS Storm Prediction Center Norman OK 1113 PM CDT Wed Aug 07 2019 Areas affected...Southern SD...Northern NE Concerning...Severe potential...Watch unlikely Valid 080413Z - 080545Z Probability of Watch Issuance...20 percent SUMMARY...Some hail threat, along with gusty winds, are possible with storms along the SD/NE border region for the next several hours. Severe thunderstorm watch is not anticipated. DISCUSSION...Weak warm advection appears mostly responsible for recent elevated convection along the SD/NE border. This activity is developing just north of a weak front that is sagging slowly south across the central Plains. Forecast soundings across the central Plains exhibit more than adequate cloud-layer shear for sustained updrafts; however, forecast hail algorithm is not particularly aggressive with with values generally on the order of 1" or less. Even so, hail likely accompanies more organized supercells. Will continue to monitor this region but it remains unclear whether this activity will achieve sustained severe levels warranting a severe thunderstorm watch. ..Darrow/Hart.. 08/08/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...OAX...LBF...UNR... LAT...LON 43560014 42829688 42059777 42700072 43180136 43560014 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Wed Aug 07 2019 Valid 080100Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered storms are expected tonight across parts of the Central Plains, with hail or wind possible. Otherwise, a decreasing severe threat is expected across the Great Lakes, Mid Atlantic, and Lower Mississippi Valley where isolated strong wind gusts remain possible. ...Central Plains... A moist and unstable air mass remains over much of the central states, with sporadic storms across many states. One possible corridor of focused severe threat is expected to develop along and north of a stationary front extending from eastern CO across KS and into southwest MO. Southwesterly 850 mb winds are expected to increase tonight, which will increase warm advection near this boundary. The steep lapse rate environment beneath modest northwest flow aloft should support scattered storms in a northwest-southeast zone along the front, with hail and locally damaging wind gusts possible. ...WI.. Cooler and drier air will continue to surge across WI behind a cold front, and will continue to support scattered thunderstorms. The instability axis currently extends northeastward out of IA and into WI, and this is where isolated marginally severe storms are possible. A weakening trend is expected with the loss of heating, thus the threat may only exist for a couple hours. ..Jewell.. 08/08/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Wed Aug 07 2019 Valid 080100Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered storms are expected tonight across parts of the Central Plains, with hail or wind possible. Otherwise, a decreasing severe threat is expected across the Great Lakes, Mid Atlantic, and Lower Mississippi Valley where isolated strong wind gusts remain possible. ...Central Plains... A moist and unstable air mass remains over much of the central states, with sporadic storms across many states. One possible corridor of focused severe threat is expected to develop along and north of a stationary front extending from eastern CO across KS and into southwest MO. Southwesterly 850 mb winds are expected to increase tonight, which will increase warm advection near this boundary. The steep lapse rate environment beneath modest northwest flow aloft should support scattered storms in a northwest-southeast zone along the front, with hail and locally damaging wind gusts possible. ...WI.. Cooler and drier air will continue to surge across WI behind a cold front, and will continue to support scattered thunderstorms. The instability axis currently extends northeastward out of IA and into WI, and this is where isolated marginally severe storms are possible. A weakening trend is expected with the loss of heating, thus the threat may only exist for a couple hours. ..Jewell.. 08/08/2019 Read more

WW 0561 Status Updates
000-080040- STATUS REPORT ON WW 561 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM AND 25 NNE NHK TO 15 SSW DOV TO 25 NE DOV TO 20 WNW ACY TO 25 E PHL TO 15 S EWR TO 20 NNW BDR TO 5 SSW BAF TO 30 SSW EEN TO 35 W EEN TO 10 E GFL TO 35 NNW GFL. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1670 ..COOK..08/07/19 ATTN...WFO...OKX...BOX...ALY...PHI...GYX...BGM...CTP...BTV... STATUS REPORT FOR WS 561 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-003-007-009-011-013-015-080040- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM DEC005-080040- DE . DELAWARE COUNTIES INCLUDED ARE SUSSEX MAC011-013-015-017-027-080040- Read more

WW 561 SEVERE TSTM CT DE MA MD NH NJ NY PA VT CW 071810Z - 080100Z
0-080100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 561 NWS Storm Prediction Center Norman OK 210 PM EDT Wed Aug 7 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Delaware much of Massachusetts eastern Maryland southern New Hampshire New Jersey southeastern New York eastern Pennsylvania southern Vermont Coastal Waters * Effective this Wednesday afternoon and evening from 210 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...Strong/locally severe storms will continue to develop/shift eastward this afternoon, with locally damaging winds and hail expected. Threat will diminish gradually through early evening. The severe thunderstorm watch area is approximately along and 75 statute miles east and west of a line from 35 miles north northeast of Albany NY to 25 miles west of Philadelphia PA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). 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 559...WW 560... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27035. ...Goss Read more

WW 0560 Status Updates
STATUS REPORT ON WW 560 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 WNW OAJ TO 30 WNW EWN TO 45 N EWN TO 10 SSE ECG TO 55 E ECG. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1671 ..COOK..08/07/19 ATTN...WFO...LWX...AKQ...MHX...RAH... STATUS REPORT FOR WS 560 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NCC013-031-049-055-095-103-133-137-177-187-080040- NC . NORTH CAROLINA COUNTIES INCLUDED ARE BEAUFORT CARTERET CRAVEN DARE HYDE JONES ONSLOW PAMLICO TYRRELL WASHINGTON AMZ131-135-136-137-150-230-231-080040- CW . ADJACENT COASTAL WATERS INCLUDED ARE ALLIGATOR RIVER PAMLICO SOUND PAMLICO AND PUNGO RIVERS Read more

WW 560 SEVERE TSTM DC MD NC VA CW 071755Z - 080000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 560 NWS Storm Prediction Center Norman OK 155 PM EDT Wed Aug 7 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of District Of Columbia eastern Maryland central and eastern North Carolina northern and eastern Virginia Coastal Waters * Effective this Wednesday afternoon and evening from 155 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...Strong/locally severe storms will continue to develop and spread eastward across the Mid-Atlantic region and North Carolina this afternoon. Locally damaging winds will be the main risk, through early evening. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 35 miles northwest of Dover DE to 40 miles southwest of Goldsboro NC. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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 559... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 27035. ...Goss Read more

MD 1671 CONCERNING SEVERE THUNDERSTORM WATCH 560... FOR EASTERN NORTH CAROLINA...A SMALL PART OF NORTHEASTERN VIRGINIA
Mesoscale Discussion 1671 NWS Storm Prediction Center Norman OK 0615 PM CDT Wed Aug 07 2019 Areas affected...eastern North Carolina...a small part of northeastern Virginia Concerning...Severe Thunderstorm Watch 560... Valid 072315Z - 080015Z The severe weather threat for Severe Thunderstorm Watch 560 continues. SUMMARY...A lingering, isolated severe threat exists, although the majority of the severe threat has diminished across WW 560. DISCUSSION...A loosely organized band of storms continues to persist along and ahead of an outflow/mature cold pool moving through eastern North Carolina. Though moderate instability remains in place along and ahead of the band of storms, weak low-level shear was continuing to support limited organization and outflow-dominant activity containing mostly sub-severe wind gusts. Still, an isolated severe gust will remain possible over the next hour or so as storms forward-propagate toward the Outer Banks. Farther north, a very isolated severe threat will remain across northeastern Virginia along a slowly southward-moving outflow between LKU and EZF. A spatially focused pocket of instability remains in place in this region - which has mainly been unaffected by more substantial convective overturning to the east. This threat is not sufficient to necessitate a continued WW, though wind/tree damage cannot be completely ruled out. ..Cook.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...LWX... LAT...LON 35837535 35427548 35007606 34887691 35037752 35327762 35877698 36437634 37417657 37947719 38047764 38217769 38347734 38287675 38087649 37887653 37517644 37127622 36587570 36327531 36217520 35837535 Read more

MD 1670 CONCERNING SEVERE THUNDERSTORM WATCH 561... FOR EASTERN MARYLAND...DELAWARE...NEW JERSEY...EASTERN AND SOUTHERN NEW YORK...CONNECTICUT...MASSACHUSETTS...SOUTHERN NEW HAMPSHIRE...AND SOUTHERN VERMONT
Mesoscale Discussion 1670 NWS Storm Prediction Center Norman OK 0556 PM CDT Wed Aug 07 2019 Areas affected...eastern Maryland...Delaware...New Jersey...eastern and southern New York...Connecticut...Massachusetts...southern New Hampshire...and southern Vermont Concerning...Severe Thunderstorm Watch 561... Valid 072256Z - 080000Z The severe weather threat for Severe Thunderstorm Watch 561 continues. SUMMARY...The severe threat continues across remaining portions of WW 561. Clearing of the Watch behind an extensive band of storms entering the discussion area may continue. DISCUSSION...Storms have gradually grown upscale into convective bands across the southern half of the discussion area (from near Long Island, NY southwestward through Delaware), with more scattered convection located across southern New England and east-central New York. These storms remain in a moderately unstable pre-convective environment characterized by 2000-3000 J/kg MUCAPE, with modest shear resulting in mostly outflow-dominant storms. Damaging wind are the main threats, though isolated instances of large hail cannot be ruled out. West of these storms, convective overturning has lowered the severe threat, and these portions of WW 561 have been canceled early. As storms approach open waters of the far northwestern Atlantic, additional clearing will likely be needed. ..Cook.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...AKQ... LAT...LON 43297500 43587439 43837313 43537218 42977151 42267150 41707188 41027236 39927365 39007477 38497543 38567618 38657642 39097622 39737553 40577445 41287360 41867313 42387323 42837384 43017466 43217511 43297500 Read more

MD 1669 CONCERNING SEVERE THUNDERSTORM WATCH 559... FOR MID SOUTH
Mesoscale Discussion 1669 NWS Storm Prediction Center Norman OK 0534 PM CDT Wed Aug 07 2019 Areas affected...Mid South Concerning...Severe Thunderstorm Watch 559... Valid 072234Z - 080000Z The severe weather threat for Severe Thunderstorm Watch 559 continues. SUMMARY...Strong storms are shifting southeast across ww559. DISCUSSION...Remnants of long-lived MCS are shifting southeast across the Bootheel of MO toward western TN. Organized convection has been noted ahead of this feature since early this morning and the leading edge of robust thunderstorms now extend from northern AL-MS into central AR where activity is quite isolated. Severe threat is expected to decrease and shift south of ww559 over the next hour or so. Upstream storms that spread across southeast KS toward northwestern AR could produce marginally severe hail but this convection should remain mostly sub severe. ..Darrow.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...MEG...LSX...LZK...SGF...TSA... LAT...LON 35779391 37819291 36248891 34218988 35779391 Read more

WW 0559 Status Updates
STATUS REPORT ON WW 559 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 NE SGF TO 30 E FLP TO 45 SSE BVX TO 30 WNW MEM TO 20 ESE DYR. ..SPC..08/07/19 ATTN...WFO...LZK...TSA...MEG...PAH...SGF... STATUS REPORT FOR WS 559 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC035-077-095-107-117-123-072340- AR . ARKANSAS COUNTIES INCLUDED ARE CRITTENDEN LEE MONROE PHILLIPS PRAIRIE ST. FRANCIS MSC027-033-093-107-119-137-143-072340- MS . MISSISSIPPI COUNTIES INCLUDED ARE COAHOMA DESOTO MARSHALL PANOLA QUITMAN TATE TUNICA TNC033-047-053-075-157-167-072340- TN . TENNESSEE COUNTIES INCLUDED ARE CROCKETT FAYETTE GIBSON Read more