Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1031 AM CDT Sun Aug 25 2019 Valid 251700Z - 261200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHEAST NEVADA...SOUTHERN IDAHO...NORTHERN UTAH...SOUTHERN WYOMING...NORTHWEST COLORADO... The critical areas were joined and minor modifications were made elsewhere based on latest guidance and observations. The forecast remains on track, and please see the discussion below for more details. ..Nauslar.. 08/25/2019 .PREV DISCUSSION... /ISSUED 0109 AM CDT Sun Aug 25 2019/ ...Synopsis... A strong mid-level jet will push into the central Rockies today, on the back side of a broad upper-level trough along the Canadian border. At the surface, a cold front will move across the Intermountain West. Boundary-layer mixing of stronger flow aloft along with a more stout surface pressure gradient than recent days will lead to critical fire weather conditions across portions of both the northern Great Basin and central Rockies. Winds of 20-25 mph will be common across the highlighted critical area. Potential for 25+ mph sustained winds, and higher gusts, will be maximized underneath the mid-level jet core in the Snake River Valley and southern Wyoming. Elevated conditions will occur surrounding the critical area as winds in these locations will either be lighter (15-20 mph) and/or fuels will be slightly less receptive to fire spread. All areas that have been highlighted can expect 10-15% RH during the afternoon. Only minor changes have been made from the previous forecast on account of the latest guidance. The critical area in northeast Nevada was expanded slightly westward and the elevated area was expanded to include more of central Colorado. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Sun Aug 25 2019 Valid 251300Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE DAKOTAS AND NORTHWESTERN MINNESOTA THIS AFTERNOON AND EVENING... ...SUMMARY... Thunderstorms with severe hail and severe gusts are expected over parts of the Dakotas and northwestern Minnesota this afternoon and evening. ...Synopsis... The mid/upper-level pattern will continue to be dominated by a mean negatively tilted trough from western Canada across the central CONUS to the lower Mississippi Valley region. The associated belt of greatest northern-stream cyclonic flow will shift eastward from the Pacific Northwest across the northern Rockies and northern Plains through the period, with height falls and difluent flow spreading over the Dakotas. Several low-amplitude shortwaves are embedded in that cyclonic-flow field. The leading one -- now apparent in moisture-channel imagery over the central Dakotas -- will move eastward across MN today and this evening, while weakening. This feature will be followed closely by another over eastern MT and northeastern WY, and still another initially located over southern BC and WA. The latter trough will be the strongest by tonight, while crossing MT. Farther southeast near the mean trough, a series of slower-moving, mesoscale trough in midlevels, anchored by MCVs, will populate the skies. The best-defined MCV in satellite and composited radar imagery is located over northeastern KS in the MHK/FRI area. The associated perturbation should move eastward over MO through the period. Meanwhile, a pre-existing height weakness near the LA Gulf Coast will phase with the mean trough as heights fall south of the MCV-related perturbation. At the surface, 11Z analysis depicted a quasistationary frontal zone from the Mid-South region across northern AR and southwestern MO, intercepted by outflow over the southern KS/MO border, then evident again across east-central portions of NE and SD. Where not baroclinically overwhelmed by MCS outflow, this boundary should move little through the period, except for some weak eastward-moving/ warm-frontal behavior over the eastern Dakotas/Red River of the North region. A weak cold front, analyzed from a low NE of GGW southwestward across eastern MT, and a prefrontal/lee trough, will move eastward to western ND during the day. ...Dakotas/northwestern MN... Scattered thunderstorms are expected to develop this afternoon as convergence related to the weak front and a surface trough impinge om a corridor of favorable moisture and buoyancy. A mix of organized multicells and a few supercells is expected, with large hail and severe gusts possible, while a tornado cannot be ruled out. As height falls and cooling/destabilization aloft spread across the warm sector, diurnal heating will further contribute to steepening deep-layer lapse rates, atop a plume of 60s F surface dew points near and west of the eastern frontal zone. Modified RAOBs and model soundings indicate that the peak MLCAPE -- behind the morning clouds/convection related to the initial perturbation -- should reach 2000-2500 J/kg, despite patchy cloud cover. 35-45 kt effective-shear magnitudes will support convective organization, as will strong upper-level/ventilating winds. Low-level flow will be modest and, in much of the area, veered west of southerly, limiting hodograph size. Overall weakening of convection is expected late evening into the overnight hours as remaining activity moves deeper into/atop a progressively more-stable boundary layer within and east of the slow-moving surface warm-frontal zone. In each outlook level, slightly more room as been allotted for this process to occur into northwestern MN. ...Southern Plains to Ozarks region... Isolated gusts near severe limits still may occur with ongoing convection moving southeastward from the END area over central OK, before it weakens. See SPC mesoscale discussion 1856 for additional near-term details. Otherwise, widely scattered to scattered thunderstorms are expected to develop through this afternoon over portions of the Ozarks and vicinity, amidst rich low-level moisture (70s F surface dew points, roughly 2-inch PW) and minimal MLCINH. Activity should be focused along and ahead of the outflow boundaries from the morning MCS activity over portions of KS/OK. A general westward increase in midlevel lapse rates, combined with surface diabatic heating and aforementioned moisture, should contribute to MLCAPE ranging from around 3500 J/kg over parts of eastern OK to 1000-1500 J/kg in the frontal zone across the Ozarks region. Although some large-scale support may be provided in the form of weak DCVA and/or mesobeta- scale midlevel gradient-flow enhancement around the MCV(s), overall organization of the convection should be loose and multicellular in nature given weak low-level shear and modest mid/upper winds in most of the region. Damaging to severe gusts are possible in strongly water-loaded downdrafts, but the unconditional severe threat appears isolated and marginal. ..Edwards/Gleason.. 08/25/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Sun Aug 25 2019 Valid 251300Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE DAKOTAS AND NORTHWESTERN MINNESOTA THIS AFTERNOON AND EVENING... ...SUMMARY... Thunderstorms with severe hail and severe gusts are expected over parts of the Dakotas and northwestern Minnesota this afternoon and evening. ...Synopsis... The mid/upper-level pattern will continue to be dominated by a mean negatively tilted trough from western Canada across the central CONUS to the lower Mississippi Valley region. The associated belt of greatest northern-stream cyclonic flow will shift eastward from the Pacific Northwest across the northern Rockies and northern Plains through the period, with height falls and difluent flow spreading over the Dakotas. Several low-amplitude shortwaves are embedded in that cyclonic-flow field. The leading one -- now apparent in moisture-channel imagery over the central Dakotas -- will move eastward across MN today and this evening, while weakening. This feature will be followed closely by another over eastern MT and northeastern WY, and still another initially located over southern BC and WA. The latter trough will be the strongest by tonight, while crossing MT. Farther southeast near the mean trough, a series of slower-moving, mesoscale trough in midlevels, anchored by MCVs, will populate the skies. The best-defined MCV in satellite and composited radar imagery is located over northeastern KS in the MHK/FRI area. The associated perturbation should move eastward over MO through the period. Meanwhile, a pre-existing height weakness near the LA Gulf Coast will phase with the mean trough as heights fall south of the MCV-related perturbation. At the surface, 11Z analysis depicted a quasistationary frontal zone from the Mid-South region across northern AR and southwestern MO, intercepted by outflow over the southern KS/MO border, then evident again across east-central portions of NE and SD. Where not baroclinically overwhelmed by MCS outflow, this boundary should move little through the period, except for some weak eastward-moving/ warm-frontal behavior over the eastern Dakotas/Red River of the North region. A weak cold front, analyzed from a low NE of GGW southwestward across eastern MT, and a prefrontal/lee trough, will move eastward to western ND during the day. ...Dakotas/northwestern MN... Scattered thunderstorms are expected to develop this afternoon as convergence related to the weak front and a surface trough impinge om a corridor of favorable moisture and buoyancy. A mix of organized multicells and a few supercells is expected, with large hail and severe gusts possible, while a tornado cannot be ruled out. As height falls and cooling/destabilization aloft spread across the warm sector, diurnal heating will further contribute to steepening deep-layer lapse rates, atop a plume of 60s F surface dew points near and west of the eastern frontal zone. Modified RAOBs and model soundings indicate that the peak MLCAPE -- behind the morning clouds/convection related to the initial perturbation -- should reach 2000-2500 J/kg, despite patchy cloud cover. 35-45 kt effective-shear magnitudes will support convective organization, as will strong upper-level/ventilating winds. Low-level flow will be modest and, in much of the area, veered west of southerly, limiting hodograph size. Overall weakening of convection is expected late evening into the overnight hours as remaining activity moves deeper into/atop a progressively more-stable boundary layer within and east of the slow-moving surface warm-frontal zone. In each outlook level, slightly more room as been allotted for this process to occur into northwestern MN. ...Southern Plains to Ozarks region... Isolated gusts near severe limits still may occur with ongoing convection moving southeastward from the END area over central OK, before it weakens. See SPC mesoscale discussion 1856 for additional near-term details. Otherwise, widely scattered to scattered thunderstorms are expected to develop through this afternoon over portions of the Ozarks and vicinity, amidst rich low-level moisture (70s F surface dew points, roughly 2-inch PW) and minimal MLCINH. Activity should be focused along and ahead of the outflow boundaries from the morning MCS activity over portions of KS/OK. A general westward increase in midlevel lapse rates, combined with surface diabatic heating and aforementioned moisture, should contribute to MLCAPE ranging from around 3500 J/kg over parts of eastern OK to 1000-1500 J/kg in the frontal zone across the Ozarks region. Although some large-scale support may be provided in the form of weak DCVA and/or mesobeta- scale midlevel gradient-flow enhancement around the MCV(s), overall organization of the convection should be loose and multicellular in nature given weak low-level shear and modest mid/upper winds in most of the region. Damaging to severe gusts are possible in strongly water-loaded downdrafts, but the unconditional severe threat appears isolated and marginal. ..Edwards/Gleason.. 08/25/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Sun Aug 25 2019 Valid 251300Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE DAKOTAS AND NORTHWESTERN MINNESOTA THIS AFTERNOON AND EVENING... ...SUMMARY... Thunderstorms with severe hail and severe gusts are expected over parts of the Dakotas and northwestern Minnesota this afternoon and evening. ...Synopsis... The mid/upper-level pattern will continue to be dominated by a mean negatively tilted trough from western Canada across the central CONUS to the lower Mississippi Valley region. The associated belt of greatest northern-stream cyclonic flow will shift eastward from the Pacific Northwest across the northern Rockies and northern Plains through the period, with height falls and difluent flow spreading over the Dakotas. Several low-amplitude shortwaves are embedded in that cyclonic-flow field. The leading one -- now apparent in moisture-channel imagery over the central Dakotas -- will move eastward across MN today and this evening, while weakening. This feature will be followed closely by another over eastern MT and northeastern WY, and still another initially located over southern BC and WA. The latter trough will be the strongest by tonight, while crossing MT. Farther southeast near the mean trough, a series of slower-moving, mesoscale trough in midlevels, anchored by MCVs, will populate the skies. The best-defined MCV in satellite and composited radar imagery is located over northeastern KS in the MHK/FRI area. The associated perturbation should move eastward over MO through the period. Meanwhile, a pre-existing height weakness near the LA Gulf Coast will phase with the mean trough as heights fall south of the MCV-related perturbation. At the surface, 11Z analysis depicted a quasistationary frontal zone from the Mid-South region across northern AR and southwestern MO, intercepted by outflow over the southern KS/MO border, then evident again across east-central portions of NE and SD. Where not baroclinically overwhelmed by MCS outflow, this boundary should move little through the period, except for some weak eastward-moving/ warm-frontal behavior over the eastern Dakotas/Red River of the North region. A weak cold front, analyzed from a low NE of GGW southwestward across eastern MT, and a prefrontal/lee trough, will move eastward to western ND during the day. ...Dakotas/northwestern MN... Scattered thunderstorms are expected to develop this afternoon as convergence related to the weak front and a surface trough impinge om a corridor of favorable moisture and buoyancy. A mix of organized multicells and a few supercells is expected, with large hail and severe gusts possible, while a tornado cannot be ruled out. As height falls and cooling/destabilization aloft spread across the warm sector, diurnal heating will further contribute to steepening deep-layer lapse rates, atop a plume of 60s F surface dew points near and west of the eastern frontal zone. Modified RAOBs and model soundings indicate that the peak MLCAPE -- behind the morning clouds/convection related to the initial perturbation -- should reach 2000-2500 J/kg, despite patchy cloud cover. 35-45 kt effective-shear magnitudes will support convective organization, as will strong upper-level/ventilating winds. Low-level flow will be modest and, in much of the area, veered west of southerly, limiting hodograph size. Overall weakening of convection is expected late evening into the overnight hours as remaining activity moves deeper into/atop a progressively more-stable boundary layer within and east of the slow-moving surface warm-frontal zone. In each outlook level, slightly more room as been allotted for this process to occur into northwestern MN. ...Southern Plains to Ozarks region... Isolated gusts near severe limits still may occur with ongoing convection moving southeastward from the END area over central OK, before it weakens. See SPC mesoscale discussion 1856 for additional near-term details. Otherwise, widely scattered to scattered thunderstorms are expected to develop through this afternoon over portions of the Ozarks and vicinity, amidst rich low-level moisture (70s F surface dew points, roughly 2-inch PW) and minimal MLCINH. Activity should be focused along and ahead of the outflow boundaries from the morning MCS activity over portions of KS/OK. A general westward increase in midlevel lapse rates, combined with surface diabatic heating and aforementioned moisture, should contribute to MLCAPE ranging from around 3500 J/kg over parts of eastern OK to 1000-1500 J/kg in the frontal zone across the Ozarks region. Although some large-scale support may be provided in the form of weak DCVA and/or mesobeta- scale midlevel gradient-flow enhancement around the MCV(s), overall organization of the convection should be loose and multicellular in nature given weak low-level shear and modest mid/upper winds in most of the region. Damaging to severe gusts are possible in strongly water-loaded downdrafts, but the unconditional severe threat appears isolated and marginal. ..Edwards/Gleason.. 08/25/2019 Read more

MD 1856 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN/CENTRAL OK
Mesoscale Discussion 1856 NWS Storm Prediction Center Norman OK 0636 AM CDT Sun Aug 25 2019 Areas affected...Portions of northern/central OK Concerning...Severe potential...Watch unlikely Valid 251136Z - 251330Z Probability of Watch Issuance...5 percent SUMMARY...An isolated strong/gusty wind threat may continue with a small cluster of storms for the next couple of hours. However, watch issuance is not expected. DISCUSSION...A 25-35 kt southwesterly low-level jet over the central and southern High Plains is expected to diurnally weaken over the next 2-3 hours. This will likely reduce low-level mass influx into a small cluster of storms located over part of northern OK at 1135Z. A gradual weakening trend should likewise occur with this convection as it continues to move southward into a convectively overturned airmass across central OK this morning. In the meantime, isolated wind gusts of 50-60 mph capable of occasional damage will remain possible. A gust to 56 mph was recorded at the Alva OK Mesonet site at 11Z. Given current expectations for gradual weakening and the overall isolated threat, Severe Thunderstorm Watch issuance is not currently anticipated for any portion of northern/central OK this morning. ..Gleason/Edwards.. 08/25/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OUN... LAT...LON 36639887 36579833 36759794 36359756 35939731 35569719 35199741 34969777 34939832 35039875 35529912 36189913 36639887 Read more

WW 0618 Status Updates
STATUS REPORT ON WW 618 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 WNW RSL TO 20 SSW RSL TO 35 W HUT TO 10 NE P28 TO 25 ENE AVK. ..GLEASON..08/25/19 ATTN...WFO...DDC...ICT...TOP... STATUS REPORT FOR WS 618 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC007-009-033-047-097-145-151-165-185-251140- KS . KANSAS COUNTIES INCLUDED ARE BARBER BARTON COMANCHE EDWARDS KIOWA PAWNEE PRATT RUSH STAFFORD THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 618 SEVERE TSTM KS 250455Z - 251200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 618 NWS Storm Prediction Center Norman OK 1155 PM CDT Sat Aug 24 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central and Southern Kansas * Effective this Saturday night and Sunday morning from 1155 PM until 700 AM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...A cluster of storms will continue to organize/intensify and otherwise accelerate southeastward across central Kansas early in the overnight. As this occurs, damaging winds will continue to become an increasing concern from central into southern Kansas. The severe thunderstorm watch area is approximately along and 65 statute miles north and south of a line from 70 miles northwest of Medicine Lodge KS to 65 miles east northeast of Wichita KS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 616...WW 617... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 31040. ...Guyer Read more

WW 0618 Status Updates
STATUS REPORT ON WW 618 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 WNW RSL TO 20 SSW RSL TO 30 SSW ICT TO 30 NNW PNC TO 40 NNE PNC TO 45 W CNU TO 30 NW CNU. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1855 ..GLEASON..08/25/19 ATTN...WFO...DDC...ICT...TOP... STATUS REPORT FOR WS 618 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC007-009-019-033-035-047-049-073-077-095-097-145-151-155-165- 185-191-251040- KS . KANSAS COUNTIES INCLUDED ARE BARBER BARTON CHAUTAUQUA COMANCHE COWLEY EDWARDS ELK GREENWOOD HARPER KINGMAN KIOWA PAWNEE PRATT RENO RUSH STAFFORD SUMNER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

MD 1855 CONCERNING SEVERE THUNDERSTORM WATCH 618... FOR PORTIONS OF SOUTH-CENTRAL/SOUTHEASTERN KS INTO NORTHERN OK
Mesoscale Discussion 1855 NWS Storm Prediction Center Norman OK 0440 AM CDT Sun Aug 25 2019 Areas affected...Portions of south-central/southeastern KS into northern OK Concerning...Severe Thunderstorm Watch 618... Valid 250940Z - 251045Z The severe weather threat for Severe Thunderstorm Watch 618 continues. SUMMARY...Storms across southeastern Kansas may continue to produce isolated strong/gusty winds, but the overall severe threat should continue to lessen into northeastern OK. Across south-central KS, at least an isolated threat for large hail and severe wind gusts remains. Downstream watch issuance into parts of north-central Oklahoma is possible, but does not appear immediately likely. DISCUSSION...Leading line of storms across southeastern KS continues to show limited intensity per recent radar and infrared satellite imagery. This convection is moving southeastward and away from a south-southwesterly low-level jet over parts of the southern/central Plains. Given current radar trends, additional watch issuance into northeastern OK appears unlikely at this time. Across south-central KS, a string of supercells elevated above outflow from the storms now over southeastern KS are being supported by a 35-40 kt southwesterly low-level jet per KDDC VWP. These winds veer to northwesterly and strengthen to around 50-60 kt at mid/upper levels, which should continue to support updraft organization and an isolated threat for large hail. Some clustering of storms has also occurred across this region, with a wind gust of 42 kt measured at KPTT (Pratt KS) at 0915Z. Still, the outflow from earlier storms may tend to limit a greater wind threat in the short term. The overall severe threat into north-central OK remains unclear. Outflow from a separate, sub-severe cluster of storms that has moved from northwestern into central OK over the past few hours may tend to limit the wind threat with southward extent. Still, at least an isolated hail and strong/gusty wind risk may continue into a small portion of north-central OK where the airmass was not convectively overturned. While watch issuance is not immediately likely across north-central OK, trends will be closely monitored. ..Gleason.. 08/25/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA...TOP...ICT...OUN...DDC... LAT...LON 38599951 38599890 37349786 37369741 37619661 38109621 38139593 37039559 36439628 36389753 36419868 36619930 37009953 38599951 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Aug 25 2019 Valid 281200Z - 021200Z ...DISCUSSION... Guidance has come into better agreement regarding the upper pattern through much of next week. Current expectation is for the upper flow across the CONUS to trend more zonal on D4/Wednesday before a building ridge over the western CONUS slowly amplifies the pattern on D5/Thursday and D6/Friday. Favorable low-level moisture is forecast to return across the central Plains ahead of an approaching cold front on D5/Thursday. Thunderstorms are possible along the front on D5/Thursday and D6/Friday but more run-to-run and model-to-model consistency is still needed before confidence in the location and coverage of severe thunderstorms is high enough to delineate any areas. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Aug 25 2019 Valid 281200Z - 021200Z ...DISCUSSION... Guidance has come into better agreement regarding the upper pattern through much of next week. Current expectation is for the upper flow across the CONUS to trend more zonal on D4/Wednesday before a building ridge over the western CONUS slowly amplifies the pattern on D5/Thursday and D6/Friday. Favorable low-level moisture is forecast to return across the central Plains ahead of an approaching cold front on D5/Thursday. Thunderstorms are possible along the front on D5/Thursday and D6/Friday but more run-to-run and model-to-model consistency is still needed before confidence in the location and coverage of severe thunderstorms is high enough to delineate any areas. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Aug 25 2019 Valid 281200Z - 021200Z ...DISCUSSION... Guidance has come into better agreement regarding the upper pattern through much of next week. Current expectation is for the upper flow across the CONUS to trend more zonal on D4/Wednesday before a building ridge over the western CONUS slowly amplifies the pattern on D5/Thursday and D6/Friday. Favorable low-level moisture is forecast to return across the central Plains ahead of an approaching cold front on D5/Thursday. Thunderstorms are possible along the front on D5/Thursday and D6/Friday but more run-to-run and model-to-model consistency is still needed before confidence in the location and coverage of severe thunderstorms is high enough to delineate any areas. Read more

MD 1854 CONCERNING SEVERE THUNDERSTORM WATCH 618... FOR PORTIONS OF SOUTHERN/EASTERN KS AND NORTHERN OK
Mesoscale Discussion 1854 NWS Storm Prediction Center Norman OK 0320 AM CDT Sun Aug 25 2019 Areas affected...Portions of southern/eastern KS and northern OK Concerning...Severe Thunderstorm Watch 618... Valid 250820Z - 250915Z The severe weather threat for Severe Thunderstorm Watch 618 continues. SUMMARY...Isolated strong/gusty wind threat should continue across parts of south-central Kansas into northern Oklahoma. Downstream watch issuance in northern Oklahoma is appearing less likely. DISCUSSION...Ongoing bowing cluster of storms moving across south-central into southeastern KS has produced mainly sub-severe winds over the past 1-2 hours. A recent peak wind gust to 35 kt was observed at KICT (Wichita KS), which is in line with gradually diminishing velocities observed on radar imagery. Still, an isolated strong/gusty wind threat should persist with this convection as it continued to move southeastward through the pre-dawn hours. An embedded supercell has recently strengthened on the northern flank of this line across Morris County KS, which suggests an isolated threat for large hail may also continue in/near Severe Thunderstorm Watch 618. Given recent observational trends, downstream watch issuance into northern OK is appearing less likely in the short term. To the west of the main line, a southwesterly 30-35 kt low-level jet observed on the KDDC VWP is encouraging the development of another small cluster across parts of south-central KS. It remains unclear whether this convection will become sufficiently organized in the wake of outflow from the leading bow to pose a severe wind threat. But, a threat for isolated large hail and strong/gusty winds may be increasing across western portions of Severe Thunderstorm Watch 618 in the next hour or so. ..Gleason.. 08/25/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA...TOP...ICT...OUN...DDC... LAT...LON 38459951 38439891 38309854 37969835 37779773 37969715 38379696 38969696 38819624 37969595 36989598 36529611 36379659 36349760 36499871 37019952 38459951 Read more

WW 0618 Status Updates
STATUS REPORT ON WW 618 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 WNW RSL TO 20 SSW RSL TO 25 W HUT TO 5 SSW HUT TO 25 E HUT TO 40 SE SLN TO 30 ESE SLN TO 25 W MHK. ..GLEASON..08/25/19 ATTN...WFO...DDC...ICT...TOP... STATUS REPORT FOR WS 618 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC007-009-015-017-019-033-035-041-047-049-073-077-079-095-097- 115-145-151-155-165-173-185-191-250840- KS . KANSAS COUNTIES INCLUDED ARE BARBER BARTON BUTLER CHASE CHAUTAUQUA COMANCHE COWLEY DICKINSON EDWARDS ELK GREENWOOD HARPER HARVEY KINGMAN KIOWA MARION PAWNEE PRATT RENO RUSH SEDGWICK STAFFORD SUMNER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sun Aug 25 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN OK AND NORTHERN TX... ...SUMMARY... Isolated severe thunderstorms are possible across southern Oklahoma and northern Texas on Tuesday. ...Discussion... A large and mature mid-latitude cyclone will likely be centered near the central Manitoba/Ontario border early Tuesday. Center of this cyclone is expected to move eastward into far northwestern Ontario while cyclonic flow throughout its base moves over the upper and middle MS Valleys. At the surface, a cold front will likely extend from the Upper Great Lakes southeastward through the middle MS Valley and into northwest TX. Northern portion of this front is expected to remain fairly progressive, reaching the Lower Great Lakes, Upper OH Valley, and middle TN Valley by Tuesday evening. Southern/western portion of the front are expected to be less progressive with outflow from a MCS becoming the effective boundary across southern OK/northern TX. While thunderstorms are possible along northern portions of the front, displacement east of the better vertical shear should mitigate storm intensity. Warm temperatures, ample low-level moisture, and strong convergence along the composite front should be able to overcome the warm mid-level temperatures across southern OK/northern TX. Environment supports a severe threat with any storms that develop, but location of the front is uncertain, and the lack of large-scale forcing for ascent and warm mid-level temperatures could limit storm coverage. As such, only low severe probabilities are introduced with this forecast. ..Mosier.. 08/25/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sun Aug 25 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN OK AND NORTHERN TX... ...SUMMARY... Isolated severe thunderstorms are possible across southern Oklahoma and northern Texas on Tuesday. ...Discussion... A large and mature mid-latitude cyclone will likely be centered near the central Manitoba/Ontario border early Tuesday. Center of this cyclone is expected to move eastward into far northwestern Ontario while cyclonic flow throughout its base moves over the upper and middle MS Valleys. At the surface, a cold front will likely extend from the Upper Great Lakes southeastward through the middle MS Valley and into northwest TX. Northern portion of this front is expected to remain fairly progressive, reaching the Lower Great Lakes, Upper OH Valley, and middle TN Valley by Tuesday evening. Southern/western portion of the front are expected to be less progressive with outflow from a MCS becoming the effective boundary across southern OK/northern TX. While thunderstorms are possible along northern portions of the front, displacement east of the better vertical shear should mitigate storm intensity. Warm temperatures, ample low-level moisture, and strong convergence along the composite front should be able to overcome the warm mid-level temperatures across southern OK/northern TX. Environment supports a severe threat with any storms that develop, but location of the front is uncertain, and the lack of large-scale forcing for ascent and warm mid-level temperatures could limit storm coverage. As such, only low severe probabilities are introduced with this forecast. ..Mosier.. 08/25/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sun Aug 25 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN OK AND NORTHERN TX... ...SUMMARY... Isolated severe thunderstorms are possible across southern Oklahoma and northern Texas on Tuesday. ...Discussion... A large and mature mid-latitude cyclone will likely be centered near the central Manitoba/Ontario border early Tuesday. Center of this cyclone is expected to move eastward into far northwestern Ontario while cyclonic flow throughout its base moves over the upper and middle MS Valleys. At the surface, a cold front will likely extend from the Upper Great Lakes southeastward through the middle MS Valley and into northwest TX. Northern portion of this front is expected to remain fairly progressive, reaching the Lower Great Lakes, Upper OH Valley, and middle TN Valley by Tuesday evening. Southern/western portion of the front are expected to be less progressive with outflow from a MCS becoming the effective boundary across southern OK/northern TX. While thunderstorms are possible along northern portions of the front, displacement east of the better vertical shear should mitigate storm intensity. Warm temperatures, ample low-level moisture, and strong convergence along the composite front should be able to overcome the warm mid-level temperatures across southern OK/northern TX. Environment supports a severe threat with any storms that develop, but location of the front is uncertain, and the lack of large-scale forcing for ascent and warm mid-level temperatures could limit storm coverage. As such, only low severe probabilities are introduced with this forecast. ..Mosier.. 08/25/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Sun Aug 25 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN OK AND NORTHERN TX... ...SUMMARY... Isolated severe thunderstorms are possible across southern Oklahoma and northern Texas on Tuesday. ...Discussion... A large and mature mid-latitude cyclone will likely be centered near the central Manitoba/Ontario border early Tuesday. Center of this cyclone is expected to move eastward into far northwestern Ontario while cyclonic flow throughout its base moves over the upper and middle MS Valleys. At the surface, a cold front will likely extend from the Upper Great Lakes southeastward through the middle MS Valley and into northwest TX. Northern portion of this front is expected to remain fairly progressive, reaching the Lower Great Lakes, Upper OH Valley, and middle TN Valley by Tuesday evening. Southern/western portion of the front are expected to be less progressive with outflow from a MCS becoming the effective boundary across southern OK/northern TX. While thunderstorms are possible along northern portions of the front, displacement east of the better vertical shear should mitigate storm intensity. Warm temperatures, ample low-level moisture, and strong convergence along the composite front should be able to overcome the warm mid-level temperatures across southern OK/northern TX. Environment supports a severe threat with any storms that develop, but location of the front is uncertain, and the lack of large-scale forcing for ascent and warm mid-level temperatures could limit storm coverage. As such, only low severe probabilities are introduced with this forecast. ..Mosier.. 08/25/2019 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Sun Aug 25 2019 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... ...Synopsis... Broad upper-level cyclonic flow will shift eastward into the northern Plains/upper-Midwest during the D2/Monday period. At the surface, high pressure will build into parts of the Pacific Northwest and northern Rockies with a thermally-induced pressure trough present across northern California. With mid-level winds waning across areas of dry fuels, as well as a generally weak surface pressure gradient across the northwestern quarter of the CONUS, fire weather concerns will be reduced below elevated levels in most locations. Locally elevated conditions will be most likely in portions of southern Wyoming and perhaps the Snake River Valley where some residual mid-level flow will exist. However, conditions are expected to be relatively brief and occur over areas with a general lack of fuels. With higher pressure over Montana and a pressure trough along the Oregon coast, portions of the Willamette Valley will see easterly downslope flow during the evening/overnight. RH values may dip to 30-35%. Based on available guidance, winds do not appear likely reach the sustained 15 mph threshold except on a localized basis. ..Wendt.. 08/25/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Sun Aug 25 2019 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... ...Synopsis... Broad upper-level cyclonic flow will shift eastward into the northern Plains/upper-Midwest during the D2/Monday period. At the surface, high pressure will build into parts of the Pacific Northwest and northern Rockies with a thermally-induced pressure trough present across northern California. With mid-level winds waning across areas of dry fuels, as well as a generally weak surface pressure gradient across the northwestern quarter of the CONUS, fire weather concerns will be reduced below elevated levels in most locations. Locally elevated conditions will be most likely in portions of southern Wyoming and perhaps the Snake River Valley where some residual mid-level flow will exist. However, conditions are expected to be relatively brief and occur over areas with a general lack of fuels. With higher pressure over Montana and a pressure trough along the Oregon coast, portions of the Willamette Valley will see easterly downslope flow during the evening/overnight. RH values may dip to 30-35%. Based on available guidance, winds do not appear likely reach the sustained 15 mph threshold except on a localized basis. ..Wendt.. 08/25/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more