SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Wed Aug 14 2024 Valid 141630Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT FOR THE MIDDLE MO VALLEY... ...SUMMARY... Scattered severe thunderstorms capable of all hazards are possible late this afternoon through the evening across portions of the middle Missouri Valley. ...MO Valley area this afternoon through tonight... An MCV over northwest IA will continue eastward today, while clusters of thunderstorms are ongoing this morning from central MO to northern AR within a low-level warm advection regime. Warm advection will slowly weaken through the day, but convective outflow with the central MO storm cluster may result in those storms persisting well into the afternoon while spreading southward. Otherwise, outflow from the morning convection will slowly modify from eastern KS into southeast NE, in advance of a midlevel shortwave trough over the central High Plains, and an associated surface cold front moving southeastward across northwest KS. The cold front and the front/outflow intersection will focus thunderstorm development late this afternoon/evening from central KS to southeast NE/southwest IA, and storms will subsequently spread eastward tonight as one or more storm clusters/MCSs across northern MO/southern IA. Low-level shear/hodograph curvature will be maintained this afternoon within the modifying outflow across the SLGT risk area, where semi-discrete supercells and a couple of tornadoes will be possible. Isolated very large hail (2-2.5 inches in diameter) will also with any persistent supercells, though the severe threat will transition primarily to damaging winds (60-75 mph) by late evening into tonight as storms grow upscale. Farther northwest, a separate clustering of storms is possible in central SD, south of the ongoing convection across southern ND. Surface heating in cloud breaks and weak ascent downstream from an ejecting midlevel trough will help focus thunderstorm development by 21-00z. Low-midlevel vertical shear will not be particularly strong and flow aloft will be strongly backed, which suggests a fairly quick growth into a line segment. Isolated damaging gusts and large hail will be possible for a few hours late this afternoon/evening. ...WY and vicinity this afternoon... An embedded vorticity maximum over southeast ID will progress eastward over WY this afternoon/evening. There will be sufficient low-midlevel moisture and surface heating for high-based thunderstorm development by early afternoon in advance of the vorticity maximum. Given steep low-level lapse rates and modest enhancement to midlevel flow (near 30 kt), strong outflow winds of 50-60 mph will be possible with this convection through the afternoon. ..Thompson/Weinman.. 08/14/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1044 AM CDT Wed Aug 14 2024 Valid 141700Z - 151200Z The previous forecast remains on track based on morning observations and latest guidance. Isolated thunderstorms remain likely after 00 UTC across far northern CA, spreading into central and eastern OR through 12 UTC Thursday. Pockets of wetting rainfall are possible, but PWAT values around 0.75 inches and storm motions between 20-25 knots should support the potential for sporadic dry lightning strikes over a region with dry fuels. Other forecast concerns outlined in the previous discussion below remain valid. ..Moore.. 08/14/2024 .PREV DISCUSSION... /ISSUED 0126 AM CDT Wed Aug 14 2024/ ...Synopsis... A mid-level shortwave trough is forecast to cross the northern California coast Wednesday evening into Thursday morning, bringing with it forcing for ascent supportive of isolated dry thunderstorms. The greatest chances for dry thunderstorms will be across portions of northern California and southern Oregon. ...Dry Thunderstorms... Forecast sounding profiles still suggest the most unstable/buoyant parcels will originate at temperatures near or colder than 0 C, leaving some uncertainty in charge separation/lightning potential across the Northwest. However, forcing from the shortwave trough should be sufficient enough for at least some thunderstorm development overnight Wednesday into Thursday morning over receptive fuels. ...Dry/Windy... The strongest surface winds supportive of Elevated fire-weather conditions across the Western U.S. will be confined to diurnally/terrain-driven corridors that are too localized for highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No Mesoscale Discussions are in effect as of Wed Aug 14 14:00:02 UTC 2024.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0729 AM CDT Wed Aug 14 2024 Valid 141300Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR EASTERN NEBRASKA...SOUTHWEST IOWA...NORTHEAST KANSAS...AND NORTHWEST MISSOURI... ...SUMMARY... Scattered severe thunderstorms capable of all hazards are possible late this afternoon through the evening across adjacent portions of the mid and lower Missouri Valley. ...Synopsis... Water-vapor imagery this morning shows a mid- to upper-level shortwave trough over WY/CO moving east-northeast. This upper feature is forecast to rotate through the base of a larger-scale trough and move into the eastern ND/northern MN vicinity by daybreak Thursday. In its wake, an upstream perturbation will move from southeast OR/southern ID into NE by late tonight. Consequently, an upper ridge will shift eastward from the lower-mid MO Valley through the mid MS Valley during the period. At the surface, weak/broad low pressure initially over the High Plains is forecast to gradually consolidate as it shifts eastward across the central Plains, in tandem with the advance of the upper trough. As this occurs, a cool front will shift southeastward across the central Plains through the afternoon and evening. Overnight, further consolidation of the surface low is expected as it moves slowly northeastward into southern Minnesota, while the trailing front sharpens, extending from the low southwestward across Kansas and into New Mexico by the end of the period. ...Mid to lower Missouri Valley... Mid morning radar/IR satellite mosaic shows an MCS over northern MO/IA with a well-developed MCV moving east-northeast over northeast NE. This activity will continue to weaken this morning and become increasingly displaced from KS/NE where a renewed focus for thunderstorm development will occur later today. The remnant outflow boundary will likely persist into the afternoon across the southeastern Nebraska/northwestern Missouri/southwestern Iowa area and modify as heating occurs to the west edge of the MCS cirrus canopy. Rich low-level moisture was sampled this morning on the Topeka, KS 12 UTC raob (16.7 g/kg lowest 100-mb mean mixing ratio). Southerly low-level flow will aid in moistening the airmass as insolation contributes to moderate to strong buoyancy (2000-4000 J/kg MLCAPE) by peak heating. By late afternoon as low pressure and the cold front shifts eastward into this area, the low/front and remnant outflow should all provide low-level foci for storm initiation. With enhanced southerly low-level flow ahead of the advancing mid-level trough beneath moderate (30 to 40 kt) mid-level westerlies, resulting shear suggests that initial storms will likely be supercells capable of producing large hail (1 to 2.5 inches in diameter). Enlarged hodographs along and north of the modified outflow boundary suggest a tornado risk will probably accompany a couple of the more intense supercells, where surface to 0.5 km flow remains relatively backed beneath a belt of 30-40 700-mb flow. Given modest flow above 300 mb, upscale growth into a cluster is forecast to occur relatively quickly during the early evening with a band further consolidating into a eastward-moving line by mid to late evening. Coincident with the transition to upscale growth, the tornado risk will gradually wane and severe gusts capable of wind damage will become the primary concern. This activity will likely persist as a linear MCS but the severe threat should lessen with east extent towards the MS River late. ...Wyoming and vicinity eastward across the northern and central Plains... As the upper trough -- comprised of several vorticity maxima embedded in the broader cyclonic flow field -- shifts across the Rockies toward/into the Plains, daytime heating beneath cooler air at mid levels will support modest destabilization across a broad area. Ascent -- focused near favored higher terrain areas and near various weak surface boundaries -- will contribute to widely scattered thunderstorm development during the afternoon. Moderate mid-level westerlies will contribute to shear sufficient for a few stronger storms -- and attendant risks for hail and locally strong/severe wind gusts into the evening hours. ..Smith.. 08/14/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Aug 14 2024 Valid 171200Z - 221200Z ...DISCUSSION... Medium-range guidance remains in good agreement that upper ridging will remain prominent, and probably further amplify, over much of the Rockies/Plains this weekend into early next week. An upper trough should progress slowly eastward from the Midwest/OH Valley to the eastern states on Day 4/Saturday. While an isolated severe risk may exist across parts of the Mid-Atlantic into the Southeast ahead of a weak front, the overall environment currently appears too marginal given modest deep-layer shear to warrant inclusion of a 15% severe area for Saturday. Otherwise, an upper trough/low should mostly remain off the coast of the Pacific Northwest through at least early next week, before possibly advancing inland towards the end of the forecast period (around Day 8/Wednesday). There is a fair amount of uncertainty regarding potential suppression of the upper ridge early next week. Regardless, the severe threat across the CONUS may tend to remain fairly isolated in this time frame, with the exception of potential MCS development from parts of the Plains into the Midwest/OH Valley in a northwesterly mid-level flow regime. But, predictability remains far too low to include any areas early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Aug 14 2024 Valid 171200Z - 221200Z ...DISCUSSION... Medium-range guidance remains in good agreement that upper ridging will remain prominent, and probably further amplify, over much of the Rockies/Plains this weekend into early next week. An upper trough should progress slowly eastward from the Midwest/OH Valley to the eastern states on Day 4/Saturday. While an isolated severe risk may exist across parts of the Mid-Atlantic into the Southeast ahead of a weak front, the overall environment currently appears too marginal given modest deep-layer shear to warrant inclusion of a 15% severe area for Saturday. Otherwise, an upper trough/low should mostly remain off the coast of the Pacific Northwest through at least early next week, before possibly advancing inland towards the end of the forecast period (around Day 8/Wednesday). There is a fair amount of uncertainty regarding potential suppression of the upper ridge early next week. Regardless, the severe threat across the CONUS may tend to remain fairly isolated in this time frame, with the exception of potential MCS development from parts of the Plains into the Midwest/OH Valley in a northwesterly mid-level flow regime. But, predictability remains far too low to include any areas early next week. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Wed Aug 14 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES INTO THE OHIO/TENNESSEE VALLEYS AND MID-SOUTH... ...SUMMARY... At least isolated strong to severe thunderstorms may develop Friday over portions of the Great Lakes into the Ohio/Tennessee Valleys and Mid-South. ...Great Lakes into the Ohio/Tennessee Valleys and Mid-South... As upper ridging remains suppressed across parts of the Southwest and southern Plains, an upper trough should continue to progress slowly eastward over portions of the Great Lakes/Midwest and OH Valley on Friday. A belt of enhanced mid-level flow should be present over parts of the mid MS Valley into the OH Valley, and related deep-layer shear should be sufficient for some updraft organization with thunderstorms that can develop through the period. A weak/occluded surface low beneath the upper cyclone should likewise develop slowly eastward over the Great Lakes and southern Ontario. An ill-defined front/wind shift is forecast to extend south-southwestward from this surface low. Thunderstorms will probably be ongoing Friday morning over parts of the OH Valley. This activity is generally expected to remain sub-severe and further weaken through the morning/early afternoon as it moves eastward into a less unstable airmass. Some recovery is expected to the west of the early-day convection and ahead of the weak front, with a rather moist low-level airmass forecast to be in place from portions of the lower OH Valley into the TN Valley and Mid-South vicinity. While deep-layer shear is forecast to gradually weaken with southward extent, a broad area of at least moderate instability should develop in tandem with daytime heating along and east/southeast of the front. Any thunderstorms that do develop could become strong to severe with mainly a hail/wind threat given the forecast environment, but considerable uncertainty remains concerning details of convective initiation and development. Only weak low-level convergence along the surface front also lends uncertainty in where greater severe thunderstorm coverage may occur. Therefore, for now have included a broad Marginal Risk for Friday. But, higher severe probabilities may eventually be needed if confidence increases in an MCS/cluster occurring. ..Gleason.. 08/14/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Wed Aug 14 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES INTO THE OHIO/TENNESSEE VALLEYS AND MID-SOUTH... ...SUMMARY... At least isolated strong to severe thunderstorms may develop Friday over portions of the Great Lakes into the Ohio/Tennessee Valleys and Mid-South. ...Great Lakes into the Ohio/Tennessee Valleys and Mid-South... As upper ridging remains suppressed across parts of the Southwest and southern Plains, an upper trough should continue to progress slowly eastward over portions of the Great Lakes/Midwest and OH Valley on Friday. A belt of enhanced mid-level flow should be present over parts of the mid MS Valley into the OH Valley, and related deep-layer shear should be sufficient for some updraft organization with thunderstorms that can develop through the period. A weak/occluded surface low beneath the upper cyclone should likewise develop slowly eastward over the Great Lakes and southern Ontario. An ill-defined front/wind shift is forecast to extend south-southwestward from this surface low. Thunderstorms will probably be ongoing Friday morning over parts of the OH Valley. This activity is generally expected to remain sub-severe and further weaken through the morning/early afternoon as it moves eastward into a less unstable airmass. Some recovery is expected to the west of the early-day convection and ahead of the weak front, with a rather moist low-level airmass forecast to be in place from portions of the lower OH Valley into the TN Valley and Mid-South vicinity. While deep-layer shear is forecast to gradually weaken with southward extent, a broad area of at least moderate instability should develop in tandem with daytime heating along and east/southeast of the front. Any thunderstorms that do develop could become strong to severe with mainly a hail/wind threat given the forecast environment, but considerable uncertainty remains concerning details of convective initiation and development. Only weak low-level convergence along the surface front also lends uncertainty in where greater severe thunderstorm coverage may occur. Therefore, for now have included a broad Marginal Risk for Friday. But, higher severe probabilities may eventually be needed if confidence increases in an MCS/cluster occurring. ..Gleason.. 08/14/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0150 AM CDT Wed Aug 14 2024 Valid 151200Z - 161200Z ...Synopsis... A mid-level shortwave trough is forecast to cross the northern California coast early Thursday morning and deepen over western Oregon during the afternoon hours, bringing with it multiple rounds of isolated dry thunderstorms across central and eastern Oregon. ...Dry Thunderstorms... Some dry thunderstorms are expected to be ongoing at the start of the period Thursday morning. However, the greatest likelihood for thunderstorms will be in the afternoon and early evening hours, where a mix of scattered wet/dry thunderstorms are forecast across central and eastern Oregon. Even though fuels are near or at the 90th annual percentile over much of Oregon, the mix of wet/dry thunderstorms and relatively slow storm motions should result in at least some wetting rainfall limiting the overall threat despite scattered storm coverage. ...Dry/Windy... Surface winds are expected to remain below Elevated fire-weather criteria, except for where diurnally and terrain-driven winds are locally maximized. Given the localized nature of the better surface winds, no highlights are expected at this time. ..Halbert/Wendt.. 08/14/2024 ...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 0126 AM CDT Wed Aug 14 2024 Valid 141200Z - 151200Z ...Synopsis... A mid-level shortwave trough is forecast to cross the northern California coast Wednesday evening into Thursday morning, bringing with it forcing for ascent supportive of isolated dry thunderstorms. The greatest chances for dry thunderstorms will be across portions of northern California and southern Oregon. ...Dry Thunderstorms... Forecast sounding profiles still suggest the most unstable/buoyant parcels will originate at temperatures near or colder than 0 C, leaving some uncertainty in charge separation/lightning potential across the Northwest. However, forcing from the shortwave trough should be sufficient enough for at least some thunderstorm development overnight Wednesday into Thursday morning over receptive fuels. ...Dry/Windy... The strongest surface winds supportive of Elevated fire-weather conditions across the Western U.S. will be confined to diurnally/terrain-driven corridors that are too localized for highlights at this time. ..Halbert/Wendt.. 08/14/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Aug 14 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN KANSAS INTO THE MID MISSISSIPPI VALLEY/MIDWEST... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. Damaging winds and large hail should be the main threats, but a couple tornadoes may also occur. ...Midwest/Mid Mississippi Valley... A mid/upper-level trough should gradually amplify and deepen over the Upper Midwest on Thursday, eventually transitioning to a closed upper low. A gradual intensification of mid-level westerly flow is forecast across parts of the east-central Plains into the mid MS Valley vicinity through the day. At the surface, a weak low may gradually occlude beneath the upper cyclone through the period, with a trailing front extending southwestward from this low across parts of the Midwest into the central and southern Plains. In the wake of mainly elevated thunderstorms that should be ongoing Thursday morning, low-level southwesterly flow should support airmass recovery and robust destabilization Thursday afternoon from parts of the east-central Plains into the mid MS Valley and Midwest. Relatively steep mid-level lapse rates overlying rich low-level moisture (upper 60s to mid 70s surface dewpoints) will likely foster strong to locally extreme instability, with MLCAPE potentially in the 2500-4000+ J/kg range across the warm sector by late Thursday afternoon. Meanwhile, gradually strengthening mid-level flow will support effective bulk shear values around 30-45 kt, resulting in a conditionally rather favorable environment for severe thunderstorms. The details of convective initiation and evolution still remain rather uncertain due to weak low-level convergence along the synoptic front. Regardless, isolated to widely scattered thunderstorms should develop by late Thursday afternoon along this boundary, and potentially near any remnant outflow boundaries from earlier convection. Supercells with a threat of large hail, localized damaging gusts, and a couple tornadoes will be possible initially, with some upscale growth potentially leading to an increase in severe/damaging wind potential by Thursday evening, as thunderstorms move into parts of southern MO/IL and vicinity. ...Southern/Central Plains... With robust daytime heating, a deeply mixed boundary layer is expected to occur along/south of the front across parts of southern KS into OK. While deep-layer shear should remain weak across most of this region, moderate to strong instability and steepened low to mid-level lapse rates should support mainly an isolated severe wind threat with high-based thunderstorms that can develop. Occasional hail may also occur with the strongest cores. ..Gleason.. 08/14/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Aug 14 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN KANSAS INTO THE MID MISSISSIPPI VALLEY/MIDWEST... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. Damaging winds and large hail should be the main threats, but a couple tornadoes may also occur. ...Midwest/Mid Mississippi Valley... A mid/upper-level trough should gradually amplify and deepen over the Upper Midwest on Thursday, eventually transitioning to a closed upper low. A gradual intensification of mid-level westerly flow is forecast across parts of the east-central Plains into the mid MS Valley vicinity through the day. At the surface, a weak low may gradually occlude beneath the upper cyclone through the period, with a trailing front extending southwestward from this low across parts of the Midwest into the central and southern Plains. In the wake of mainly elevated thunderstorms that should be ongoing Thursday morning, low-level southwesterly flow should support airmass recovery and robust destabilization Thursday afternoon from parts of the east-central Plains into the mid MS Valley and Midwest. Relatively steep mid-level lapse rates overlying rich low-level moisture (upper 60s to mid 70s surface dewpoints) will likely foster strong to locally extreme instability, with MLCAPE potentially in the 2500-4000+ J/kg range across the warm sector by late Thursday afternoon. Meanwhile, gradually strengthening mid-level flow will support effective bulk shear values around 30-45 kt, resulting in a conditionally rather favorable environment for severe thunderstorms. The details of convective initiation and evolution still remain rather uncertain due to weak low-level convergence along the synoptic front. Regardless, isolated to widely scattered thunderstorms should develop by late Thursday afternoon along this boundary, and potentially near any remnant outflow boundaries from earlier convection. Supercells with a threat of large hail, localized damaging gusts, and a couple tornadoes will be possible initially, with some upscale growth potentially leading to an increase in severe/damaging wind potential by Thursday evening, as thunderstorms move into parts of southern MO/IL and vicinity. ...Southern/Central Plains... With robust daytime heating, a deeply mixed boundary layer is expected to occur along/south of the front across parts of southern KS into OK. While deep-layer shear should remain weak across most of this region, moderate to strong instability and steepened low to mid-level lapse rates should support mainly an isolated severe wind threat with high-based thunderstorms that can develop. Occasional hail may also occur with the strongest cores. ..Gleason.. 08/14/2024 Read more

MD 1898 CONCERNING SEVERE THUNDERSTORM WATCH 621... FOR SOUTH-CENTRAL INTO SOUTHEAST NE
Mesoscale Discussion 1898 NWS Storm Prediction Center Norman OK 0105 AM CDT Wed Aug 14 2024 Areas affected...south-central into southeast NE Concerning...Severe Thunderstorm Watch 621... Valid 140605Z - 140700Z The severe weather threat for Severe Thunderstorm Watch 621 continues. SUMMARY...A focused corridor for strong to locally severe gusts (50-65 mph) will extend through the eastern part of Severe Thunderstorm Watch #621 and perhaps a few counties farther east. A local watch extension-in-area could be utilized if observational trends warrant. DISCUSSION...Radar imagery shows a mature bowing segment with an implied Rear Inflow Jet moving quickly east across southern NE at 50 mph. Strong low-level warm-air advection indicative in the KUEX VAD data (45 kt southerly flow at 1.5 km AGL) will continue to sustain a background environment favorable for a continuation of the bowing segment into eastern portions of NE through the early overnight. Surface analysis shows temperatures ranging from the upper 60s to lower 70s with mid to upper 60s dewpoints ahead of the squall line. Appreciable convective inhibition and a gradual lessening of buoyancy (per objective analysis data and 00 UTC area raob data) will likely limit and constrict the corridor for strong to severe gusts to the apex of the bow and immediate adjacent areas before this potential diminishes in eastern NE. ..Smith.. 08/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...GID... LAT...LON 40849907 41049833 41079758 40899731 40639727 40429742 40329828 40409902 40849907 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Aug 14 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTERED OVER THE MIDDLE MISSOURI VALLEY AREA... ...SUMMARY... Isolated severe thunderstorms are expected today from parts of the Intermountain West eastward across the northern and central Plains. A more concentrated risk -- including potential for large hail and damaging winds, and possibly a tornado -- is expected across the mid Missouri Valley area. ...Synopsis... A low-amplitude mid-level trough is forecast to move out of the Intermountain West and into the northern/central Plains today, shunting the central U.S. ridge eastward across the Mississippi Valley and into the Great Lakes/Ohio and Tennessee Valleys. Farther downstream, an eastern U.S. trough will gradually shift off the East Coast and into the western Atlantic. Meanwhile upstream, an eastern Pacific short-wave trough will move into the Pacific Northwest/northern California through the second half of the period. At the surface, weak/broad low pressure initially over the High Plains is forecast to gradually consolidate as it shifts eastward across the central Plains, in tandem with the advance of the upper trough. As this occurs, a cool front will shift southeastward across the central Plains through the afternoon and evening. Overnight, further consolidation of the surface low is expected as it moves slowly northeastward into southern Minnesota, while the trailing front sharpens, extending from the low southwestward across Kansas and into New Mexico by the end of the period. ...Middle Missouri Valley area... As an ongoing MCS crosses the Mid Missouri Valley area of eastern Nebraska and vicinity early in the period, a resulting/remnant outflow boundary is forecast to persist into the afternoon across the southeastern Nebraska/northwestern Missouri/southwestern Iowa area. As a moist low-level airmass undergoes diurnal heating, moderate destabilization is forecast near and south of this boundary. As low pressure -- and the attendant cold front -- shifts eastward into this area, the low/front and remnant outflow should all provide low-level foci for late afternoon storm initiation. With enhanced southerly low-level flow ahead of the advancing mid-level trough beneath moderate (30 to 40 kt) mid-level westerlies, resulting shear suggests that initial storms will likely be supercells, capable of producing large hail and damaging winds, and possibly a tornado. With time, clustering/upscale growth is expected, with guidance suggesting that an at least loosely organized band of storms should move eastward through the evening across, northwestern Missouri, and eastern Kansas. Risk for locally damaging wind gusts and some hail will likely accompany this activity, before severe risk diminishes gradually overnight. ...Wyoming and vicinity eastward across the northern and central Plains... As the upper trough -- comprised of several vorticity maxima embedded in the broader cyclonic flow field -- shifts across the Rockies toward/into the Plains, daytime heating beneath cooler air at mid levels will support modest destabilization across a broad area. Ascent -- focused near favored higher terrain areas and near various weak surface boundaries -- will contribute to widely scattered thunderstorm development during the afternoon. Moderate mid-level westerlies will contribute to shear sufficient for a few stronger storms -- and attendant risks for hail and locally strong/severe wind gusts into the evening hours. ..Goss/Halbert.. 08/14/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Aug 14 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTERED OVER THE MIDDLE MISSOURI VALLEY AREA... ...SUMMARY... Isolated severe thunderstorms are expected today from parts of the Intermountain West eastward across the northern and central Plains. A more concentrated risk -- including potential for large hail and damaging winds, and possibly a tornado -- is expected across the mid Missouri Valley area. ...Synopsis... A low-amplitude mid-level trough is forecast to move out of the Intermountain West and into the northern/central Plains today, shunting the central U.S. ridge eastward across the Mississippi Valley and into the Great Lakes/Ohio and Tennessee Valleys. Farther downstream, an eastern U.S. trough will gradually shift off the East Coast and into the western Atlantic. Meanwhile upstream, an eastern Pacific short-wave trough will move into the Pacific Northwest/northern California through the second half of the period. At the surface, weak/broad low pressure initially over the High Plains is forecast to gradually consolidate as it shifts eastward across the central Plains, in tandem with the advance of the upper trough. As this occurs, a cool front will shift southeastward across the central Plains through the afternoon and evening. Overnight, further consolidation of the surface low is expected as it moves slowly northeastward into southern Minnesota, while the trailing front sharpens, extending from the low southwestward across Kansas and into New Mexico by the end of the period. ...Middle Missouri Valley area... As an ongoing MCS crosses the Mid Missouri Valley area of eastern Nebraska and vicinity early in the period, a resulting/remnant outflow boundary is forecast to persist into the afternoon across the southeastern Nebraska/northwestern Missouri/southwestern Iowa area. As a moist low-level airmass undergoes diurnal heating, moderate destabilization is forecast near and south of this boundary. As low pressure -- and the attendant cold front -- shifts eastward into this area, the low/front and remnant outflow should all provide low-level foci for late afternoon storm initiation. With enhanced southerly low-level flow ahead of the advancing mid-level trough beneath moderate (30 to 40 kt) mid-level westerlies, resulting shear suggests that initial storms will likely be supercells, capable of producing large hail and damaging winds, and possibly a tornado. With time, clustering/upscale growth is expected, with guidance suggesting that an at least loosely organized band of storms should move eastward through the evening across, northwestern Missouri, and eastern Kansas. Risk for locally damaging wind gusts and some hail will likely accompany this activity, before severe risk diminishes gradually overnight. ...Wyoming and vicinity eastward across the northern and central Plains... As the upper trough -- comprised of several vorticity maxima embedded in the broader cyclonic flow field -- shifts across the Rockies toward/into the Plains, daytime heating beneath cooler air at mid levels will support modest destabilization across a broad area. Ascent -- focused near favored higher terrain areas and near various weak surface boundaries -- will contribute to widely scattered thunderstorm development during the afternoon. Moderate mid-level westerlies will contribute to shear sufficient for a few stronger storms -- and attendant risks for hail and locally strong/severe wind gusts into the evening hours. ..Goss/Halbert.. 08/14/2024 Read more

WW 0621 Status Updates
STATUS REPORT ON WW 621 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 ESE MCK TO 30 SW EAR TO 5 SSW BUB. ..SMITH..08/14/24 ATTN...WFO...GID...LBF... STATUS REPORT FOR WS 621 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC001-019-061-065-077-079-083-093-099-137-163-175-181-140630- NE . NEBRASKA COUNTIES INCLUDED ARE ADAMS BUFFALO FRANKLIN FURNAS GREELEY HALL HARLAN HOWARD KEARNEY PHELPS SHERMAN VALLEY WEBSTER 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 621 SEVERE TSTM NE 140430Z - 141200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 621 NWS Storm Prediction Center Norman OK 1130 PM CDT Tue Aug 13 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central and south-central Nebraska * Effective this Tuesday night and Wednesday morning from 1130 PM until 700 AM CDT. * Primary threats include... Isolated damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A cluster of occasionally severe thunderstorms -- which produced a 60-kt at MCK during the last half hour -- will maintain severe potential into the watch area before weakening later tonight. Isolated large hail also may occur, either in the main MCS or in precursory convection. The severe thunderstorm watch area is approximately along and 50 statute miles east and west of a line from 50 miles south southwest of Kearney NE to 30 miles northeast of Broken Bow NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 620... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 27030. ...Edwards Read more

WW 0620 Status Updates
STATUS REPORT ON WW 620 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 S ITR TO 35 WSW MCK TO 15 WNW MCK TO 35 NNW MCK TO 30 W LBF TO 45 SW MHN. ..BROYLES..08/14/24 ATTN...WFO...BOU...GLD...LBF...CYS... STATUS REPORT FOR WS 620 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC023-039-109-137-153-179-181-193-199-140540- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR LOGAN NORTON RAWLINS SHERIDAN SHERMAN THOMAS WALLACE NEC029-057-063-085-087-111-135-145-140540- NE . NEBRASKA COUNTIES INCLUDED ARE CHASE DUNDY FRONTIER HAYES HITCHCOCK LINCOLN PERKINS RED WILLOW 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 620 SEVERE TSTM CO KS NE 132250Z - 140700Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 620 NWS Storm Prediction Center Norman OK 450 PM MDT Tue Aug 13 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of East-central and northeastern Colorado Northwestern Kansas Southwestern Nebraska * Effective this Tuesday afternoon and Wednesday morning from 450 PM until 100 AM MDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...Initially widely scattered strong-severe thunderstorms east of the Front Range should become denser in coverage and organize into one or more clusters, with increasing severe potential over the next several hours as the activity moves eastward across the High Plains, into greater moisture. The severe thunderstorm watch area is approximately along and 80 statute miles north and south of a line from 45 miles west northwest of Akron CO to 25 miles northeast of Mccook NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 27030. ...Edwards Read more

MD 1897 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTH-CENTRAL NEBRASKA AND NORTH-CENTRAL KANSAS
Mesoscale Discussion 1897 NWS Storm Prediction Center Norman OK 1000 PM CDT Tue Aug 13 2024 Areas affected...South-central Nebraska and North-central Kansas Concerning...Severe potential...Watch possible Valid 140300Z - 140500Z Probability of Watch Issuance...60 percent SUMMARY...A new severe thunderstorm watch may be needed as a linear MCS continues to process eastward across southern Nebraska and northern Kansas. DISCUSSION...A linear MCS with a history of 60-70 MPH observed winds is continuing to progress across portions of northern Kansas and southern Nebraska, with a pronounced bow echo evident on radar in southern Nebraska. This bow echo will serve as the primary focus for the greatest short-term severe risk over the next few hours. Some uncertainty remains in the eastward longevity of this convective line, but SPC mesoanalysis suggests that continued warm air advection in the low levels has limited nocturnal boundary layer stabilization and subsequent development of MLCINH. The expectation is that the line will eventually weaken with eastward extent, but a new severe thunderstorm watch may be necessary if the line maintains its current strength. ..Halbert/Wendt/Edwards.. 08/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...DDC...GLD... LAT...LON 38730069 38710122 39090149 39770154 40740111 41250077 41480026 41539928 41519865 40959811 40389800 39739797 39519820 39369870 39329885 39139940 38910010 38730069 Read more