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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1206 PM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS AND LOUISIANA... ...SUMMARY... Isolated severe thunderstorms are possible across north Texas into western Louisiana Tuesday. ...TX/LA... Large-scale height falls will spread across the upper MS Valley into the Great Lakes region Tuesday ahead of a notable, progressive upper trough. Southern-most direct influence of this feature will extend into the mid MS Valley; however, surface pressures will build across the Plains in the wake of the short wave. This will drive a front to near the Red River by daybreak as mid/high-level flow becomes more northwesterly. Convection will likely be ongoing at the start of the period along the trailing front across AR/OK and this should aid southward push into north TX by early afternoon. Latest model guidance suggests strongest boundary-layer heating will be noted ahead of the wind shift from the Edwards Plateau into east-central TX where convective temperatures should be breached, perhaps as early as 20z. While early-day convection will not likely dissipate before this occurs, strongest updrafts should develop where surface temperatures warm into the mid 90s. Forecast soundings from ABI and SEP exhibit substantial SBCAPE at 20z with PW on the order of 2". While deep-layer flow will be weak, isolated damaging wind gusts are certainly possible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Darrow.. 08/26/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1206 PM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS AND LOUISIANA... ...SUMMARY... Isolated severe thunderstorms are possible across north Texas into western Louisiana Tuesday. ...TX/LA... Large-scale height falls will spread across the upper MS Valley into the Great Lakes region Tuesday ahead of a notable, progressive upper trough. Southern-most direct influence of this feature will extend into the mid MS Valley; however, surface pressures will build across the Plains in the wake of the short wave. This will drive a front to near the Red River by daybreak as mid/high-level flow becomes more northwesterly. Convection will likely be ongoing at the start of the period along the trailing front across AR/OK and this should aid southward push into north TX by early afternoon. Latest model guidance suggests strongest boundary-layer heating will be noted ahead of the wind shift from the Edwards Plateau into east-central TX where convective temperatures should be breached, perhaps as early as 20z. While early-day convection will not likely dissipate before this occurs, strongest updrafts should develop where surface temperatures warm into the mid 90s. Forecast soundings from ABI and SEP exhibit substantial SBCAPE at 20z with PW on the order of 2". While deep-layer flow will be weak, isolated damaging wind gusts are certainly possible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Darrow.. 08/26/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1206 PM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS AND LOUISIANA... ...SUMMARY... Isolated severe thunderstorms are possible across north Texas into western Louisiana Tuesday. ...TX/LA... Large-scale height falls will spread across the upper MS Valley into the Great Lakes region Tuesday ahead of a notable, progressive upper trough. Southern-most direct influence of this feature will extend into the mid MS Valley; however, surface pressures will build across the Plains in the wake of the short wave. This will drive a front to near the Red River by daybreak as mid/high-level flow becomes more northwesterly. Convection will likely be ongoing at the start of the period along the trailing front across AR/OK and this should aid southward push into north TX by early afternoon. Latest model guidance suggests strongest boundary-layer heating will be noted ahead of the wind shift from the Edwards Plateau into east-central TX where convective temperatures should be breached, perhaps as early as 20z. While early-day convection will not likely dissipate before this occurs, strongest updrafts should develop where surface temperatures warm into the mid 90s. Forecast soundings from ABI and SEP exhibit substantial SBCAPE at 20z with PW on the order of 2". While deep-layer flow will be weak, isolated damaging wind gusts are certainly possible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Darrow.. 08/26/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1206 PM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS AND LOUISIANA... ...SUMMARY... Isolated severe thunderstorms are possible across north Texas into western Louisiana Tuesday. ...TX/LA... Large-scale height falls will spread across the upper MS Valley into the Great Lakes region Tuesday ahead of a notable, progressive upper trough. Southern-most direct influence of this feature will extend into the mid MS Valley; however, surface pressures will build across the Plains in the wake of the short wave. This will drive a front to near the Red River by daybreak as mid/high-level flow becomes more northwesterly. Convection will likely be ongoing at the start of the period along the trailing front across AR/OK and this should aid southward push into north TX by early afternoon. Latest model guidance suggests strongest boundary-layer heating will be noted ahead of the wind shift from the Edwards Plateau into east-central TX where convective temperatures should be breached, perhaps as early as 20z. While early-day convection will not likely dissipate before this occurs, strongest updrafts should develop where surface temperatures warm into the mid 90s. Forecast soundings from ABI and SEP exhibit substantial SBCAPE at 20z with PW on the order of 2". While deep-layer flow will be weak, isolated damaging wind gusts are certainly possible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Darrow.. 08/26/2019 Read more

MD 1866 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHEAST KANSAS INTO SOUTHWEST MISSOURI
Mesoscale Discussion 1866 NWS Storm Prediction Center Norman OK 1142 AM CDT Mon Aug 26 2019 Areas affected...southeast Kansas into southwest Missouri Concerning...Severe potential...Watch possible Valid 261642Z - 261745Z Probability of Watch Issuance...60 percent SUMMARY...Storms may continue to pose a risk for damaging wind and large hail as they develop into southwest MO. A ww might be required soon. DISCUSSION...MCS has evolved into a line segment just south of the Kansas City area and continues southeast at around 40 kt. Storms may still be slightly elevated, but the downstream atmosphere is destabilizing with temperatures rising through the 80s along with low 70s F dewpoints supporting moderate instability. The concern is that these storms may eventually become surface based as the boundary layer continues to warm and convective inhibition weakens, with convergence along the gust front supporting a forward propagating MCS. ..Dial/Thompson.. 08/26/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SGF...EAX... LAT...LON 38019493 38299447 38549414 38379349 38139246 37259258 37189453 38019493 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Mon Aug 26 2019 Valid 261630Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF MO...KS...AND OK... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...MO/KS/OK through tonight... A midlevel trough over the Dakotas is in the process of evolving into a closed low near the international border. A series of embedded speed maxima will rotate through the southern periphery of the trough from NE/KS to the middle MS Valley. At the surface, a cold front will continue to move southeastward across KS toward OK. A weak low is expected to form near the intersection of this cold front and a separate baroclinic zone near the KS/MO border by late afternoon. This baroclinic zone will be reinforced and likely shifted south by outflow and differential heating associated with the ongoing storms near Kansas City, and the evolution of these ongoing storms pose the greatest uncertainty in the forecast for this afternoon/evening across MO. Large buoyancy (MLCAPE of 3000-4500 J/kg) is expected in the warm sector this afternoon as surface heating occurs within a moist boundary layer (mid 70s dewpoints) beneath steep midlevel lapse rates. The cap is weaker with eastward extent across MO, and the ongoing storms could become rooted at the surface by early afternoon, which would suggest the potential for large hail and damaging winds this afternoon into central MO. In the wake of the ongoing convection, renewed storm development is expected 21-23z near the triple point and along the cold front near the KS/MO border, though the northward extent of the threat is uncertain given the influence of the ongoing storms. Deep-layer vertical shear will be sufficient for supercells, while low-level hodograph curvature/SRH will be maximized near the outflow-reinforced baroclinic zone this afternoon/evening in MO. Cross-frontal shear vectors with storm motions to the east-southeast 25-30 kt should allow semi-discrete storms for a couple of hours late this afternoon/evening, with an attendant threat for a couple of tornadoes and isolated very large hail. Otherwise, cell mergers should lead to upscale growth into clusters/line segments. Damaging winds will become a primary threat with the clusters/line segments in an environment favoring strong downdrafts, and the threat for wind damage will persist into the early overnight hours. Weaker forcing for ascent and a warmer elevated mixed layer will tend to delay storm initiation until this evening farther southwest along the cold front into northern OK. Wind profiles will be sufficient for marginal supercells and/or organized clusters capable of producing isolated large hail. Damaging winds should be the primary threat given steep low-level lapse rates, large DCAPE, and precipitation loading with updrafts in a large CAPE environment. ...IL/IN this afternoon... A lead shortwave trough will eject northeastward from IL toward northern IN and Lower MI and weaken this afternoon, along with an accompanying surface cyclone in northern IL. Boundary-layer dewpoints near 70 F are present in the warm sector of the cyclone, though widespread clouds will tend to slow surface heating. There is some potential for renewed storm development this afternoon in a broken band across eastern IL into northwestern IN, where low-level shear will be marginally favorable for supercells and perhaps a brief tornado. ..Thompson/Cook.. 08/26/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Mon Aug 26 2019 Valid 261630Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF MO...KS...AND OK... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...MO/KS/OK through tonight... A midlevel trough over the Dakotas is in the process of evolving into a closed low near the international border. A series of embedded speed maxima will rotate through the southern periphery of the trough from NE/KS to the middle MS Valley. At the surface, a cold front will continue to move southeastward across KS toward OK. A weak low is expected to form near the intersection of this cold front and a separate baroclinic zone near the KS/MO border by late afternoon. This baroclinic zone will be reinforced and likely shifted south by outflow and differential heating associated with the ongoing storms near Kansas City, and the evolution of these ongoing storms pose the greatest uncertainty in the forecast for this afternoon/evening across MO. Large buoyancy (MLCAPE of 3000-4500 J/kg) is expected in the warm sector this afternoon as surface heating occurs within a moist boundary layer (mid 70s dewpoints) beneath steep midlevel lapse rates. The cap is weaker with eastward extent across MO, and the ongoing storms could become rooted at the surface by early afternoon, which would suggest the potential for large hail and damaging winds this afternoon into central MO. In the wake of the ongoing convection, renewed storm development is expected 21-23z near the triple point and along the cold front near the KS/MO border, though the northward extent of the threat is uncertain given the influence of the ongoing storms. Deep-layer vertical shear will be sufficient for supercells, while low-level hodograph curvature/SRH will be maximized near the outflow-reinforced baroclinic zone this afternoon/evening in MO. Cross-frontal shear vectors with storm motions to the east-southeast 25-30 kt should allow semi-discrete storms for a couple of hours late this afternoon/evening, with an attendant threat for a couple of tornadoes and isolated very large hail. Otherwise, cell mergers should lead to upscale growth into clusters/line segments. Damaging winds will become a primary threat with the clusters/line segments in an environment favoring strong downdrafts, and the threat for wind damage will persist into the early overnight hours. Weaker forcing for ascent and a warmer elevated mixed layer will tend to delay storm initiation until this evening farther southwest along the cold front into northern OK. Wind profiles will be sufficient for marginal supercells and/or organized clusters capable of producing isolated large hail. Damaging winds should be the primary threat given steep low-level lapse rates, large DCAPE, and precipitation loading with updrafts in a large CAPE environment. ...IL/IN this afternoon... A lead shortwave trough will eject northeastward from IL toward northern IN and Lower MI and weaken this afternoon, along with an accompanying surface cyclone in northern IL. Boundary-layer dewpoints near 70 F are present in the warm sector of the cyclone, though widespread clouds will tend to slow surface heating. There is some potential for renewed storm development this afternoon in a broken band across eastern IL into northwestern IN, where low-level shear will be marginally favorable for supercells and perhaps a brief tornado. ..Thompson/Cook.. 08/26/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Mon Aug 26 2019 Valid 261630Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF MO...KS...AND OK... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...MO/KS/OK through tonight... A midlevel trough over the Dakotas is in the process of evolving into a closed low near the international border. A series of embedded speed maxima will rotate through the southern periphery of the trough from NE/KS to the middle MS Valley. At the surface, a cold front will continue to move southeastward across KS toward OK. A weak low is expected to form near the intersection of this cold front and a separate baroclinic zone near the KS/MO border by late afternoon. This baroclinic zone will be reinforced and likely shifted south by outflow and differential heating associated with the ongoing storms near Kansas City, and the evolution of these ongoing storms pose the greatest uncertainty in the forecast for this afternoon/evening across MO. Large buoyancy (MLCAPE of 3000-4500 J/kg) is expected in the warm sector this afternoon as surface heating occurs within a moist boundary layer (mid 70s dewpoints) beneath steep midlevel lapse rates. The cap is weaker with eastward extent across MO, and the ongoing storms could become rooted at the surface by early afternoon, which would suggest the potential for large hail and damaging winds this afternoon into central MO. In the wake of the ongoing convection, renewed storm development is expected 21-23z near the triple point and along the cold front near the KS/MO border, though the northward extent of the threat is uncertain given the influence of the ongoing storms. Deep-layer vertical shear will be sufficient for supercells, while low-level hodograph curvature/SRH will be maximized near the outflow-reinforced baroclinic zone this afternoon/evening in MO. Cross-frontal shear vectors with storm motions to the east-southeast 25-30 kt should allow semi-discrete storms for a couple of hours late this afternoon/evening, with an attendant threat for a couple of tornadoes and isolated very large hail. Otherwise, cell mergers should lead to upscale growth into clusters/line segments. Damaging winds will become a primary threat with the clusters/line segments in an environment favoring strong downdrafts, and the threat for wind damage will persist into the early overnight hours. Weaker forcing for ascent and a warmer elevated mixed layer will tend to delay storm initiation until this evening farther southwest along the cold front into northern OK. Wind profiles will be sufficient for marginal supercells and/or organized clusters capable of producing isolated large hail. Damaging winds should be the primary threat given steep low-level lapse rates, large DCAPE, and precipitation loading with updrafts in a large CAPE environment. ...IL/IN this afternoon... A lead shortwave trough will eject northeastward from IL toward northern IN and Lower MI and weaken this afternoon, along with an accompanying surface cyclone in northern IL. Boundary-layer dewpoints near 70 F are present in the warm sector of the cyclone, though widespread clouds will tend to slow surface heating. There is some potential for renewed storm development this afternoon in a broken band across eastern IL into northwestern IN, where low-level shear will be marginally favorable for supercells and perhaps a brief tornado. ..Thompson/Cook.. 08/26/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Mon Aug 26 2019 Valid 261630Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF MO...KS...AND OK... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...MO/KS/OK through tonight... A midlevel trough over the Dakotas is in the process of evolving into a closed low near the international border. A series of embedded speed maxima will rotate through the southern periphery of the trough from NE/KS to the middle MS Valley. At the surface, a cold front will continue to move southeastward across KS toward OK. A weak low is expected to form near the intersection of this cold front and a separate baroclinic zone near the KS/MO border by late afternoon. This baroclinic zone will be reinforced and likely shifted south by outflow and differential heating associated with the ongoing storms near Kansas City, and the evolution of these ongoing storms pose the greatest uncertainty in the forecast for this afternoon/evening across MO. Large buoyancy (MLCAPE of 3000-4500 J/kg) is expected in the warm sector this afternoon as surface heating occurs within a moist boundary layer (mid 70s dewpoints) beneath steep midlevel lapse rates. The cap is weaker with eastward extent across MO, and the ongoing storms could become rooted at the surface by early afternoon, which would suggest the potential for large hail and damaging winds this afternoon into central MO. In the wake of the ongoing convection, renewed storm development is expected 21-23z near the triple point and along the cold front near the KS/MO border, though the northward extent of the threat is uncertain given the influence of the ongoing storms. Deep-layer vertical shear will be sufficient for supercells, while low-level hodograph curvature/SRH will be maximized near the outflow-reinforced baroclinic zone this afternoon/evening in MO. Cross-frontal shear vectors with storm motions to the east-southeast 25-30 kt should allow semi-discrete storms for a couple of hours late this afternoon/evening, with an attendant threat for a couple of tornadoes and isolated very large hail. Otherwise, cell mergers should lead to upscale growth into clusters/line segments. Damaging winds will become a primary threat with the clusters/line segments in an environment favoring strong downdrafts, and the threat for wind damage will persist into the early overnight hours. Weaker forcing for ascent and a warmer elevated mixed layer will tend to delay storm initiation until this evening farther southwest along the cold front into northern OK. Wind profiles will be sufficient for marginal supercells and/or organized clusters capable of producing isolated large hail. Damaging winds should be the primary threat given steep low-level lapse rates, large DCAPE, and precipitation loading with updrafts in a large CAPE environment. ...IL/IN this afternoon... A lead shortwave trough will eject northeastward from IL toward northern IN and Lower MI and weaken this afternoon, along with an accompanying surface cyclone in northern IL. Boundary-layer dewpoints near 70 F are present in the warm sector of the cyclone, though widespread clouds will tend to slow surface heating. There is some potential for renewed storm development this afternoon in a broken band across eastern IL into northwestern IN, where low-level shear will be marginally favorable for supercells and perhaps a brief tornado. ..Thompson/Cook.. 08/26/2019 Read more

The Roberts Fire, in the Apache Kid Wilderness in the San Mateo Mountains, located on the Magdalena Ranger District, is a lightning caused fire that began July 13, 2019. The fire is currently burning in Ponderosa Pine, grass, and brush in steep terrain with limited access. All Temporary Closure Orders have been lifted. Within the past 7 days there has been no smoke visible within the Roberts Fire perimeter. As of 4:00 PM on Friday, August 16, 2019 the Roberts Fire is 100% contained.For more information regarding the Roberts Fire, please contact the Magdalena Ranger District at (575) 854-2281, Monday-Friday, from 8:00 AM to 4:30 PM..

No watches are valid as of Mon Aug 26 15:46:01 UTC 2019.

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1013 AM CDT Mon Aug 26 2019 Valid 261700Z - 271200Z ...NO CRITICAL AREAS... No changes are necessary, and please see the discussion below for more details. ..Nauslar.. 08/26/2019 .PREV DISCUSSION... /ISSUED 0112 AM CDT Mon Aug 26 2019/ ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1013 AM CDT Mon Aug 26 2019 Valid 261700Z - 271200Z ...NO CRITICAL AREAS... No changes are necessary, and please see the discussion below for more details. ..Nauslar.. 08/26/2019 .PREV DISCUSSION... /ISSUED 0112 AM CDT Mon Aug 26 2019/ ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1013 AM CDT Mon Aug 26 2019 Valid 261700Z - 271200Z ...NO CRITICAL AREAS... No changes are necessary, and please see the discussion below for more details. ..Nauslar.. 08/26/2019 .PREV DISCUSSION... /ISSUED 0112 AM CDT Mon Aug 26 2019/ ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1013 AM CDT Mon Aug 26 2019 Valid 261700Z - 271200Z ...NO CRITICAL AREAS... No changes are necessary, and please see the discussion below for more details. ..Nauslar.. 08/26/2019 .PREV DISCUSSION... /ISSUED 0112 AM CDT Mon Aug 26 2019/ ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1865 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEAST KANSAS THROUGH EXTREME NORTHWEST MISSOURI
Mesoscale Discussion 1865 NWS Storm Prediction Center Norman OK 0920 AM CDT Mon Aug 26 2019 Areas affected...northeast Kansas through extreme northwest Missouri Concerning...Severe potential...Watch unlikely Valid 261420Z - 261545Z Probability of Watch Issuance...20 percent SUMMARY...Storms may continue to pose a risk for isolated large hail over northeast Kansas into northwest Missouri through 16Z, followed by a gradual decrease. A WW will probably not be needed, but trends will continue to be monitored. DISCUSSION...Cluster of storms continues this morning over northeast KS within a zone of isentropic ascent and warm advection north of convectively reinforced front. Morning TOP RAOB indicates 2300 J/kg MUCAPE for parcels lifted from 850 mb along with 7 C/km mid-level lapse rates and 45 kt effective bulk shear. This environment is supportive of occasional embedded supercell structures which will promote a few instances of large hail as storms develop southeast this morning. The low-level jet is forecast to gradually weaken, and storms should eventually diminish toward late morning. ..Dial/Thompson.. 08/26/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...TOP... LAT...LON 38739425 38989554 39119616 39469647 39909624 39689508 39259421 38739425 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 AM CDT Mon Aug 26 2019 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF MISSOURI...SOUTHEASTERN KANSAS...NORTHEASTERN OKLAHOMA...AND EXTREME NORTHWESTERN ARKANSAS... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...Synopsis... A progressive and amplified pattern will continue across roughly the northern 1/2 of the CONUS through the period, featuring a synoptic trough across the northern/central Plains and Upper Midwest. Numerous small shortwaves will traverse the associated cyclonic flow, including MCVs initially evident over the central Plains and mid Mississippi Valley. One of the larger shortwave troughs -- now evident in moisture-channel imagery from the southern MB/SK border southward over the western Dakotas -- should pivot generally eastward to western/central MN by 00Z. Through the rest of the period, it will eject northeastward, lose amplitude, and become absorbed in the southeastern fringes of a developing closed cyclone centered over southern Lake Winnipeg in MB. Meanwhile, an upstream perturbation -- currently over northwestern AB and northeastern BC -- will dig southeastward across southern SK and eastern MT, reaching the western Dakotas by 12Z. By that time, cyclonic flow related to the MB vortex will cover the northern/central Rockies, northern/central Plains, mid/upper Mississippi Valley, and most of the Great Lakes. At the surface, 11Z analysis showed a cold front from south- central/southeastern MB across eastern portions of ND/SD, central NE, and east-central CO. This front is forecast to move eastward/ southeastward to a 00Z position over western MN and central IA, to a surface low at or near a triple-point junction with a separate boundary over west-central MO, then southwestward across southeastern KS, northwestern OK, the southern TX Panhandle, and northeastern NM. By 12Z, this front should extend across eastern Lake Superior, Lake Michigan or western Lower MI, western IL, eastern/southern OK, and the Llano Estacado of west TX and eastern NM. ...Mid Mississippi Valley to OK... A complex scenario is underway and will continue to unfold across the region through tonight, but with the greatest severe threat still related to convective wind in and near the "enhanced" risk area. A loosely organized, ongoing complex of strong/locally severe thunderstorms over southeastern NE and northeastern KS is expected to continue moving southeastward across northeastern KS toward northwestern MO, offering the potential for sporadic severe hail/gusts through the remainder of the morning. This activity is expected to follow an instability/theta-e gradient related to the western limb of a mesoscale baroclinic boundary that extends into MO. This afternoon into evening, scattered to numerous thunderstorms are expected to form in a northeast/southwest corridor close to the front. Development may be somewhat earlier over northern parts of the combined "slight" and "enhanced" outlook areas, where EML- related MLCINH will be somewhat weaker and deep-layer forcing more robust, followed by thunderstorms in the stronger capping (but also stronger diurnal heating) of southeastern KS and northeastern to north-central OK. All severe hazards will be possible, with the hail and tornado concerns being greatest in the first few hours of the convective cyclone with any relatively discrete/sustained storms that can become supercells. Damaging wind will be likely, both from those supercells and any upscale evolution into bows and/or mergers of cold pools. A northern bound to the more-robust severe threat appears to be represented by the combined effects of two processes affecting the prefrontal sector over western/central MO and extreme eastern KS: 1. An MCV will continue to move northeastward from western IL through today. A low-level boundary produced by related convection over western IL and eastern MO arches from near STL across central and west-central MO to northeastern KS, merging with the pr-existing frontal zone. This boundary will retreat northward across western/central MO, but with some modulation by the next factor... 2. The influence of cloud cover and precip from aforementioned/ ongoing convection over the southeastern NE area. This activity is projected to shift southeastward toward northwestern MO, and some uncertain distance into/atop the relatively stable layer north of the boundary, before it dissipates. This precip and cloud over should help the air mass north of the boundary to remain relatively stable. As such, the outlook areas have been tightened across MO, and trimmed from IA, which will reside between the stronger mid/upper forcing to the north and optimally unstable boundary layer to the south. The afternoon air mass from the prefrontal boundary southwestward into northern/central OK will become strongly unstable, thanks to the overlap of steep low/middle-level lapse rates with 70s surface dew points and strong surface heating. A broad area of 4000-5000 J/kg peak preconvective MLCAPE is expected across northern OK, southern KS and western/southwestern MO, locally even higher. Buoyancy should diminish eastward across the Ozarks with weaker midlevel lapse rates, but with MLCAPE exceeding 3000 J/kg as far east as southern IL and central/eastern MO. Low-level shear and hodograph size should be relatively maximized near the prefrontal boundary, with 200-300 J/kg effective SRH possible, gradually diminishing southwestward. These conditions will support a mixture of supercells and organized/deep multicells, with modes getting messy and merged over time. The convective band may maintain a severe threat overnight into parts of central/southeastern OK, western/northern AR, and eastern MO/western IL. ...Upper Mississippi Valley... A band of thunderstorms is expected to develop near the front today and move eastward from roughly the I-35 MN corridor across western/northwestern WI during its most intense stage, with a marginal threat for severe wind/hail. Strong deep-layer lift, including large-scale ascent/cooling from an approaching shortwave trough, and the low-level mass response including frontal convergence, will contribute to the convective environment. Boundary-layer heating/lapse rates will be tempered by cloud cover and an antecedent air mass characterized by weak theta-e relative to areas farther south over MO. However, cooling aloft should steepen midlevel lapse rates enough, in combination with surface dew points generally in the mid 50s to mid 60s F, to support a corridor of 500-1000 J/kg MLCAPE, with around 30-35-kt effective-shear magnitudes. The already marginal severe potential should diminish eastward into a more-stable air mass across central/north-central WI this evening. ..Edwards/Gleason.. 08/26/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 AM CDT Mon Aug 26 2019 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF MISSOURI...SOUTHEASTERN KANSAS...NORTHEASTERN OKLAHOMA...AND EXTREME NORTHWESTERN ARKANSAS... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...Synopsis... A progressive and amplified pattern will continue across roughly the northern 1/2 of the CONUS through the period, featuring a synoptic trough across the northern/central Plains and Upper Midwest. Numerous small shortwaves will traverse the associated cyclonic flow, including MCVs initially evident over the central Plains and mid Mississippi Valley. One of the larger shortwave troughs -- now evident in moisture-channel imagery from the southern MB/SK border southward over the western Dakotas -- should pivot generally eastward to western/central MN by 00Z. Through the rest of the period, it will eject northeastward, lose amplitude, and become absorbed in the southeastern fringes of a developing closed cyclone centered over southern Lake Winnipeg in MB. Meanwhile, an upstream perturbation -- currently over northwestern AB and northeastern BC -- will dig southeastward across southern SK and eastern MT, reaching the western Dakotas by 12Z. By that time, cyclonic flow related to the MB vortex will cover the northern/central Rockies, northern/central Plains, mid/upper Mississippi Valley, and most of the Great Lakes. At the surface, 11Z analysis showed a cold front from south- central/southeastern MB across eastern portions of ND/SD, central NE, and east-central CO. This front is forecast to move eastward/ southeastward to a 00Z position over western MN and central IA, to a surface low at or near a triple-point junction with a separate boundary over west-central MO, then southwestward across southeastern KS, northwestern OK, the southern TX Panhandle, and northeastern NM. By 12Z, this front should extend across eastern Lake Superior, Lake Michigan or western Lower MI, western IL, eastern/southern OK, and the Llano Estacado of west TX and eastern NM. ...Mid Mississippi Valley to OK... A complex scenario is underway and will continue to unfold across the region through tonight, but with the greatest severe threat still related to convective wind in and near the "enhanced" risk area. A loosely organized, ongoing complex of strong/locally severe thunderstorms over southeastern NE and northeastern KS is expected to continue moving southeastward across northeastern KS toward northwestern MO, offering the potential for sporadic severe hail/gusts through the remainder of the morning. This activity is expected to follow an instability/theta-e gradient related to the western limb of a mesoscale baroclinic boundary that extends into MO. This afternoon into evening, scattered to numerous thunderstorms are expected to form in a northeast/southwest corridor close to the front. Development may be somewhat earlier over northern parts of the combined "slight" and "enhanced" outlook areas, where EML- related MLCINH will be somewhat weaker and deep-layer forcing more robust, followed by thunderstorms in the stronger capping (but also stronger diurnal heating) of southeastern KS and northeastern to north-central OK. All severe hazards will be possible, with the hail and tornado concerns being greatest in the first few hours of the convective cyclone with any relatively discrete/sustained storms that can become supercells. Damaging wind will be likely, both from those supercells and any upscale evolution into bows and/or mergers of cold pools. A northern bound to the more-robust severe threat appears to be represented by the combined effects of two processes affecting the prefrontal sector over western/central MO and extreme eastern KS: 1. An MCV will continue to move northeastward from western IL through today. A low-level boundary produced by related convection over western IL and eastern MO arches from near STL across central and west-central MO to northeastern KS, merging with the pr-existing frontal zone. This boundary will retreat northward across western/central MO, but with some modulation by the next factor... 2. The influence of cloud cover and precip from aforementioned/ ongoing convection over the southeastern NE area. This activity is projected to shift southeastward toward northwestern MO, and some uncertain distance into/atop the relatively stable layer north of the boundary, before it dissipates. This precip and cloud over should help the air mass north of the boundary to remain relatively stable. As such, the outlook areas have been tightened across MO, and trimmed from IA, which will reside between the stronger mid/upper forcing to the north and optimally unstable boundary layer to the south. The afternoon air mass from the prefrontal boundary southwestward into northern/central OK will become strongly unstable, thanks to the overlap of steep low/middle-level lapse rates with 70s surface dew points and strong surface heating. A broad area of 4000-5000 J/kg peak preconvective MLCAPE is expected across northern OK, southern KS and western/southwestern MO, locally even higher. Buoyancy should diminish eastward across the Ozarks with weaker midlevel lapse rates, but with MLCAPE exceeding 3000 J/kg as far east as southern IL and central/eastern MO. Low-level shear and hodograph size should be relatively maximized near the prefrontal boundary, with 200-300 J/kg effective SRH possible, gradually diminishing southwestward. These conditions will support a mixture of supercells and organized/deep multicells, with modes getting messy and merged over time. The convective band may maintain a severe threat overnight into parts of central/southeastern OK, western/northern AR, and eastern MO/western IL. ...Upper Mississippi Valley... A band of thunderstorms is expected to develop near the front today and move eastward from roughly the I-35 MN corridor across western/northwestern WI during its most intense stage, with a marginal threat for severe wind/hail. Strong deep-layer lift, including large-scale ascent/cooling from an approaching shortwave trough, and the low-level mass response including frontal convergence, will contribute to the convective environment. Boundary-layer heating/lapse rates will be tempered by cloud cover and an antecedent air mass characterized by weak theta-e relative to areas farther south over MO. However, cooling aloft should steepen midlevel lapse rates enough, in combination with surface dew points generally in the mid 50s to mid 60s F, to support a corridor of 500-1000 J/kg MLCAPE, with around 30-35-kt effective-shear magnitudes. The already marginal severe potential should diminish eastward into a more-stable air mass across central/north-central WI this evening. ..Edwards/Gleason.. 08/26/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 AM CDT Mon Aug 26 2019 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF MISSOURI...SOUTHEASTERN KANSAS...NORTHEASTERN OKLAHOMA...AND EXTREME NORTHWESTERN ARKANSAS... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...Synopsis... A progressive and amplified pattern will continue across roughly the northern 1/2 of the CONUS through the period, featuring a synoptic trough across the northern/central Plains and Upper Midwest. Numerous small shortwaves will traverse the associated cyclonic flow, including MCVs initially evident over the central Plains and mid Mississippi Valley. One of the larger shortwave troughs -- now evident in moisture-channel imagery from the southern MB/SK border southward over the western Dakotas -- should pivot generally eastward to western/central MN by 00Z. Through the rest of the period, it will eject northeastward, lose amplitude, and become absorbed in the southeastern fringes of a developing closed cyclone centered over southern Lake Winnipeg in MB. Meanwhile, an upstream perturbation -- currently over northwestern AB and northeastern BC -- will dig southeastward across southern SK and eastern MT, reaching the western Dakotas by 12Z. By that time, cyclonic flow related to the MB vortex will cover the northern/central Rockies, northern/central Plains, mid/upper Mississippi Valley, and most of the Great Lakes. At the surface, 11Z analysis showed a cold front from south- central/southeastern MB across eastern portions of ND/SD, central NE, and east-central CO. This front is forecast to move eastward/ southeastward to a 00Z position over western MN and central IA, to a surface low at or near a triple-point junction with a separate boundary over west-central MO, then southwestward across southeastern KS, northwestern OK, the southern TX Panhandle, and northeastern NM. By 12Z, this front should extend across eastern Lake Superior, Lake Michigan or western Lower MI, western IL, eastern/southern OK, and the Llano Estacado of west TX and eastern NM. ...Mid Mississippi Valley to OK... A complex scenario is underway and will continue to unfold across the region through tonight, but with the greatest severe threat still related to convective wind in and near the "enhanced" risk area. A loosely organized, ongoing complex of strong/locally severe thunderstorms over southeastern NE and northeastern KS is expected to continue moving southeastward across northeastern KS toward northwestern MO, offering the potential for sporadic severe hail/gusts through the remainder of the morning. This activity is expected to follow an instability/theta-e gradient related to the western limb of a mesoscale baroclinic boundary that extends into MO. This afternoon into evening, scattered to numerous thunderstorms are expected to form in a northeast/southwest corridor close to the front. Development may be somewhat earlier over northern parts of the combined "slight" and "enhanced" outlook areas, where EML- related MLCINH will be somewhat weaker and deep-layer forcing more robust, followed by thunderstorms in the stronger capping (but also stronger diurnal heating) of southeastern KS and northeastern to north-central OK. All severe hazards will be possible, with the hail and tornado concerns being greatest in the first few hours of the convective cyclone with any relatively discrete/sustained storms that can become supercells. Damaging wind will be likely, both from those supercells and any upscale evolution into bows and/or mergers of cold pools. A northern bound to the more-robust severe threat appears to be represented by the combined effects of two processes affecting the prefrontal sector over western/central MO and extreme eastern KS: 1. An MCV will continue to move northeastward from western IL through today. A low-level boundary produced by related convection over western IL and eastern MO arches from near STL across central and west-central MO to northeastern KS, merging with the pr-existing frontal zone. This boundary will retreat northward across western/central MO, but with some modulation by the next factor... 2. The influence of cloud cover and precip from aforementioned/ ongoing convection over the southeastern NE area. This activity is projected to shift southeastward toward northwestern MO, and some uncertain distance into/atop the relatively stable layer north of the boundary, before it dissipates. This precip and cloud over should help the air mass north of the boundary to remain relatively stable. As such, the outlook areas have been tightened across MO, and trimmed from IA, which will reside between the stronger mid/upper forcing to the north and optimally unstable boundary layer to the south. The afternoon air mass from the prefrontal boundary southwestward into northern/central OK will become strongly unstable, thanks to the overlap of steep low/middle-level lapse rates with 70s surface dew points and strong surface heating. A broad area of 4000-5000 J/kg peak preconvective MLCAPE is expected across northern OK, southern KS and western/southwestern MO, locally even higher. Buoyancy should diminish eastward across the Ozarks with weaker midlevel lapse rates, but with MLCAPE exceeding 3000 J/kg as far east as southern IL and central/eastern MO. Low-level shear and hodograph size should be relatively maximized near the prefrontal boundary, with 200-300 J/kg effective SRH possible, gradually diminishing southwestward. These conditions will support a mixture of supercells and organized/deep multicells, with modes getting messy and merged over time. The convective band may maintain a severe threat overnight into parts of central/southeastern OK, western/northern AR, and eastern MO/western IL. ...Upper Mississippi Valley... A band of thunderstorms is expected to develop near the front today and move eastward from roughly the I-35 MN corridor across western/northwestern WI during its most intense stage, with a marginal threat for severe wind/hail. Strong deep-layer lift, including large-scale ascent/cooling from an approaching shortwave trough, and the low-level mass response including frontal convergence, will contribute to the convective environment. Boundary-layer heating/lapse rates will be tempered by cloud cover and an antecedent air mass characterized by weak theta-e relative to areas farther south over MO. However, cooling aloft should steepen midlevel lapse rates enough, in combination with surface dew points generally in the mid 50s to mid 60s F, to support a corridor of 500-1000 J/kg MLCAPE, with around 30-35-kt effective-shear magnitudes. The already marginal severe potential should diminish eastward into a more-stable air mass across central/north-central WI this evening. ..Edwards/Gleason.. 08/26/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 AM CDT Mon Aug 26 2019 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF MISSOURI...SOUTHEASTERN KANSAS...NORTHEASTERN OKLAHOMA...AND EXTREME NORTHWESTERN ARKANSAS... ...SUMMARY... The greatest severe-weather threats today will involve thunderstorm winds and hail, in a corridor from western/central Missouri to northeastern Oklahoma. ...Synopsis... A progressive and amplified pattern will continue across roughly the northern 1/2 of the CONUS through the period, featuring a synoptic trough across the northern/central Plains and Upper Midwest. Numerous small shortwaves will traverse the associated cyclonic flow, including MCVs initially evident over the central Plains and mid Mississippi Valley. One of the larger shortwave troughs -- now evident in moisture-channel imagery from the southern MB/SK border southward over the western Dakotas -- should pivot generally eastward to western/central MN by 00Z. Through the rest of the period, it will eject northeastward, lose amplitude, and become absorbed in the southeastern fringes of a developing closed cyclone centered over southern Lake Winnipeg in MB. Meanwhile, an upstream perturbation -- currently over northwestern AB and northeastern BC -- will dig southeastward across southern SK and eastern MT, reaching the western Dakotas by 12Z. By that time, cyclonic flow related to the MB vortex will cover the northern/central Rockies, northern/central Plains, mid/upper Mississippi Valley, and most of the Great Lakes. At the surface, 11Z analysis showed a cold front from south- central/southeastern MB across eastern portions of ND/SD, central NE, and east-central CO. This front is forecast to move eastward/ southeastward to a 00Z position over western MN and central IA, to a surface low at or near a triple-point junction with a separate boundary over west-central MO, then southwestward across southeastern KS, northwestern OK, the southern TX Panhandle, and northeastern NM. By 12Z, this front should extend across eastern Lake Superior, Lake Michigan or western Lower MI, western IL, eastern/southern OK, and the Llano Estacado of west TX and eastern NM. ...Mid Mississippi Valley to OK... A complex scenario is underway and will continue to unfold across the region through tonight, but with the greatest severe threat still related to convective wind in and near the "enhanced" risk area. A loosely organized, ongoing complex of strong/locally severe thunderstorms over southeastern NE and northeastern KS is expected to continue moving southeastward across northeastern KS toward northwestern MO, offering the potential for sporadic severe hail/gusts through the remainder of the morning. This activity is expected to follow an instability/theta-e gradient related to the western limb of a mesoscale baroclinic boundary that extends into MO. This afternoon into evening, scattered to numerous thunderstorms are expected to form in a northeast/southwest corridor close to the front. Development may be somewhat earlier over northern parts of the combined "slight" and "enhanced" outlook areas, where EML- related MLCINH will be somewhat weaker and deep-layer forcing more robust, followed by thunderstorms in the stronger capping (but also stronger diurnal heating) of southeastern KS and northeastern to north-central OK. All severe hazards will be possible, with the hail and tornado concerns being greatest in the first few hours of the convective cyclone with any relatively discrete/sustained storms that can become supercells. Damaging wind will be likely, both from those supercells and any upscale evolution into bows and/or mergers of cold pools. A northern bound to the more-robust severe threat appears to be represented by the combined effects of two processes affecting the prefrontal sector over western/central MO and extreme eastern KS: 1. An MCV will continue to move northeastward from western IL through today. A low-level boundary produced by related convection over western IL and eastern MO arches from near STL across central and west-central MO to northeastern KS, merging with the pr-existing frontal zone. This boundary will retreat northward across western/central MO, but with some modulation by the next factor... 2. The influence of cloud cover and precip from aforementioned/ ongoing convection over the southeastern NE area. This activity is projected to shift southeastward toward northwestern MO, and some uncertain distance into/atop the relatively stable layer north of the boundary, before it dissipates. This precip and cloud over should help the air mass north of the boundary to remain relatively stable. As such, the outlook areas have been tightened across MO, and trimmed from IA, which will reside between the stronger mid/upper forcing to the north and optimally unstable boundary layer to the south. The afternoon air mass from the prefrontal boundary southwestward into northern/central OK will become strongly unstable, thanks to the overlap of steep low/middle-level lapse rates with 70s surface dew points and strong surface heating. A broad area of 4000-5000 J/kg peak preconvective MLCAPE is expected across northern OK, southern KS and western/southwestern MO, locally even higher. Buoyancy should diminish eastward across the Ozarks with weaker midlevel lapse rates, but with MLCAPE exceeding 3000 J/kg as far east as southern IL and central/eastern MO. Low-level shear and hodograph size should be relatively maximized near the prefrontal boundary, with 200-300 J/kg effective SRH possible, gradually diminishing southwestward. These conditions will support a mixture of supercells and organized/deep multicells, with modes getting messy and merged over time. The convective band may maintain a severe threat overnight into parts of central/southeastern OK, western/northern AR, and eastern MO/western IL. ...Upper Mississippi Valley... A band of thunderstorms is expected to develop near the front today and move eastward from roughly the I-35 MN corridor across western/northwestern WI during its most intense stage, with a marginal threat for severe wind/hail. Strong deep-layer lift, including large-scale ascent/cooling from an approaching shortwave trough, and the low-level mass response including frontal convergence, will contribute to the convective environment. Boundary-layer heating/lapse rates will be tempered by cloud cover and an antecedent air mass characterized by weak theta-e relative to areas farther south over MO. However, cooling aloft should steepen midlevel lapse rates enough, in combination with surface dew points generally in the mid 50s to mid 60s F, to support a corridor of 500-1000 J/kg MLCAPE, with around 30-35-kt effective-shear magnitudes. The already marginal severe potential should diminish eastward into a more-stable air mass across central/north-central WI this evening. ..Edwards/Gleason.. 08/26/2019 Read more