SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0250 PM CDT Thu Sep 19 2024 Valid 211200Z - 271200Z Multiple mid-level troughs will traverse the Intermountain West and eject into the central and northern Mississippi Valley through the middle of next week, encouraging surface high pressure and cooler air to gradually overspread much of the CONUS. Appreciable rainfall accumulations are likely across the southern Plains into the Ohio Valley through next week, which should help dampen very dry fuels across these regions. Approaching cooler temperatures or meaningful rainfall accumulations over much of the CONUS suggests that quiescent fire weather conditions should prevail for this upcoming week. Locally dry and breezy conditions may occur over portions of the Interior West or High Plains, but such conditions appear too localized to warrant critical probabilities this outlook. ..Squitieri.. 09/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NM INTO THE SOUTHERN HIGH PLAINS...PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS...CENTRAL APPALACHIANS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a strong midlevel jet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms could become severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be limited by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Central Plains and Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential remains evident on Saturday afternoon/evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. There is sufficient confidence in destabilization and storm coverage to introduce a 5% area from the mid MO Valley to the upper MS Valley, though uncertainty remains rather high. ...Parts of the Northeast/Mid Atlantic... A low-amplitude midlevel shortwave trough is forecast to move through northwesterly flow aloft across parts of the upper Ohio Valley into the Mid Atlantic on Saturday. Isolated to scattered thunderstorm development will be possible across the region during the afternoon. Veering wind profiles within the northwesterly flow regime will support effective shear for some storm organization, though it remains somewhat uncertain if instability will become sufficient to support an organized severe threat. Guidance has trended toward somewhat greater instability and storm coverage, and a small Marginal Risk has been included where confidence is currently highest in some severe threat. ..Dean.. 09/19/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0209 PM CDT Thu Sep 19 2024 Valid 201200Z - 211200Z ...NO CRITICAL AREAS... The previous forecast remains generally on track. A few hours of dry and occasionally breezy conditions may precede isolated thunderstorm development across northern portions of the Texas Panhandle into northwestern Oklahoma. However, the marginal nature of these conditions suggest that wildfire-spread concerns should remain localized, so no fire weather highlights have been introduced this outlook. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0121 AM CDT Thu Sep 19 2024/ ...Synopsis... A low-latitude midlevel low will advance eastward across the Lower CO River Valley, while a related belt of strong deep-layer southwesterly flow overspreads the Southwest. Boundary-layer mixing into this strong deep-layer flow will favor dry/breezy conditions across portions of western NM and eastern AZ during the afternoon. While this could lead to locally elevated fire-weather conditions, fuels are generally unsupportive of large-fire spread at this time. Elsewhere, a minimal overlap of breezy surface winds and low RH should limit fire-weather concerns. ...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 0209 PM CDT Thu Sep 19 2024 Valid 201200Z - 211200Z ...NO CRITICAL AREAS... The previous forecast remains generally on track. A few hours of dry and occasionally breezy conditions may precede isolated thunderstorm development across northern portions of the Texas Panhandle into northwestern Oklahoma. However, the marginal nature of these conditions suggest that wildfire-spread concerns should remain localized, so no fire weather highlights have been introduced this outlook. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0121 AM CDT Thu Sep 19 2024/ ...Synopsis... A low-latitude midlevel low will advance eastward across the Lower CO River Valley, while a related belt of strong deep-layer southwesterly flow overspreads the Southwest. Boundary-layer mixing into this strong deep-layer flow will favor dry/breezy conditions across portions of western NM and eastern AZ during the afternoon. While this could lead to locally elevated fire-weather conditions, fuels are generally unsupportive of large-fire spread at this time. Elsewhere, a minimal overlap of breezy surface winds and low RH should limit fire-weather concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0677 Status Updates
STATUS FOR WATCH 0677 HAS NOT BEEN ISSUED YET Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Thu Sep 19 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST AND ALSO THE SOUTH-CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible in the late afternoon Friday in parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Midwest... A low-amplitude shortwave trough will pass across the Upper to central Great Lakes during the first half of the period. This will outpace a cold front that trails from a cyclone shifting northeast in MB, yielding a largely weakening to stalling front by Friday evening. Most guidance suggests at least isolated thunderstorms should form within a low-level warm conveyor ahead of the front, generally focused on a moderate buoyancy plume emanating northeast from parts of MO/AR. A fast westerly upper jet will further impinge on this portion of the front as well, favorably timed with peak boundary-layer heating. A few marginally severe storms may develop within this regime. Despite weak mid-level lapse rates, elongation of the mid to upper hodograph should support a threat for 1-1.5 inch hail, along with strong to marginally severe gusts from 45-60 mph. These threats should diminish quickly after sunset. ...Southern KS/northern OK vicinity... A mid/upper-level shortwave trough is forecast to move slowly eastward across the Southwest on Friday. Farther east, a surface boundary initially draped from the lower MO Valley into southern KS/northern OK is forecast to lift northward as a warm front. Large-scale ascent across much of the Plains may remain relatively limited, outside of low-level warm advection near/north of the front. However, relatively strong heating along the western/northern periphery of returning low-level moisture could support thunderstorm development during the afternoon somewhere in the vicinity of southwest KS/northwest OK. Effective shear of 30-40 kt will support potential for somewhat organized convection. Strong to localized severe gusts may be the most likely hazard, but hail cannot be ruled out if any more discrete storms can move into an environment of greater moisture/instability. ...New Mexico... Scattered thunderstorms will be possible across much of NM on Friday, in closer proximity to the approaching shortwave trough. While deep-layer shear will be rather strong, generally weak midlevel lapse rates and buoyancy may tend to limit the potential for more robust storms. If confidence increases regarding sufficient heating/destabilization, then severe probabilities may eventually be needed for parts of the region. ...Central Plains into the lower MO Valley... Guidance continues to vary regarding the potential for robust elevated convection Friday night into Saturday morning, within a low-level warm advection regime. Increasing elevated buoyancy and sufficient mid/upper-level flow could support a few stronger storms with hail potential, but confidence in sufficient coverage and a favored region for this potential is too low for probabilities at this time. ..Dean.. 09/19/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Thu Sep 19 2024 Valid 191630Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST INTO EASTERN KANSAS...WESTERN MISSOURI...AND FAR NORTHEAST OKLAHOMA... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon and evening across central/eastern Minnesota, Iowa, and western Wisconsin. A couple of tornadoes, large hail, and damaging winds may occur across this region. Farther south, an area of locally severe wind gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and northeast Oklahoma. ...Minnesota/Wisconsin/Iowa... Widely spaced and mainly elevated thunderstorms ongoing late this morning across parts of IA into eastern MN and western WI should continue to diminish in coverage over the next couple of hours. In their wake, daytime heating of a seasonably moist low-level airmass (surface dewpoints generally in the 60s) and somewhat steep mid-level lapse rates will contribute to at least moderate instability by mid afternoon along/ahead of a cold front extending north to south from western MN into eastern NE and western IA. An upper low over northern ND and southeast SK/southwest MB will continue to advance slowly northeastward across south-central Canada through the period. A belt of 35-50 kt mid-level west-southwesterly winds on the southern periphery of the upper low will spread eastward from the northern Plains into the Upper Midwest through this evening. A veering/strengthening wind profile with height through mid levels will support around 30-40 kt of deep-layer shear across the warm sector. This shear will be sufficient for organized thunderstorms, including the potential for a few supercells. Current expectations are that scattered thunderstorms will develop by mid to late afternoon across central/eastern MN into northern/central IA along or just ahead of the eastward-advancing cold front. A rather favorable thermodynamic environment will foster robust updrafts, and any initial supercells should pose a threat for large to very large hail (around 1.5-2.5 inches in diameter). But, a fairly quick transition to more linear structures should occur given the presence of the cold front, with a potentially greater damaging wind threat evolving with eastward extent through the evening before convection eventually weakens. South-southwesterly low-level flow and related shear ahead of the front is not forecast to be overly strong by most guidance this afternoon. But, some threat for a couple of tornadoes remains apparent, especially with any sustained supercells across east-central/southern MN into northern IA late this afternoon/early evening. ...Eastern Kansas into Missouri and Northeast Oklahoma... An upper ridge, with rather warm mid-level temperatures, will remain centered over the southern Plains today. The surface cold front is forecast to continue moving east-southeastward across the mid MO Valley and central Plains through late this afternoon. A surface trough extending southward from this front across the southern High Plains should also mix eastward through peak daytime heating. Given weak large-scale ascent and rather warm mid-level temperatures across this area, there is still a fair amount of uncertainty regarding how many additional thunderstorms will develop later today, notwithstanding the ongoing (mainly elevated) convection over eastern KS and far northwest MO. Still, other surface-based thunderstorms may develop later this afternoon along/near the front/dryline intersection in south-central KS/north-central OK, and along the cold front in eastern KS. While low/mid-level flow should remain fairly modest, steepened low-level lapse rates and moderate instability should support a risk for mainly severe/damaging downdrafts as convection spreads east-southeastward into western MO and northeast OK through this evening. ..Gleason/Moore.. 09/19/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Thu Sep 19 2024 Valid 191630Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST INTO EASTERN KANSAS...WESTERN MISSOURI...AND FAR NORTHEAST OKLAHOMA... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon and evening across central/eastern Minnesota, Iowa, and western Wisconsin. A couple of tornadoes, large hail, and damaging winds may occur across this region. Farther south, an area of locally severe wind gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and northeast Oklahoma. ...Minnesota/Wisconsin/Iowa... Widely spaced and mainly elevated thunderstorms ongoing late this morning across parts of IA into eastern MN and western WI should continue to diminish in coverage over the next couple of hours. In their wake, daytime heating of a seasonably moist low-level airmass (surface dewpoints generally in the 60s) and somewhat steep mid-level lapse rates will contribute to at least moderate instability by mid afternoon along/ahead of a cold front extending north to south from western MN into eastern NE and western IA. An upper low over northern ND and southeast SK/southwest MB will continue to advance slowly northeastward across south-central Canada through the period. A belt of 35-50 kt mid-level west-southwesterly winds on the southern periphery of the upper low will spread eastward from the northern Plains into the Upper Midwest through this evening. A veering/strengthening wind profile with height through mid levels will support around 30-40 kt of deep-layer shear across the warm sector. This shear will be sufficient for organized thunderstorms, including the potential for a few supercells. Current expectations are that scattered thunderstorms will develop by mid to late afternoon across central/eastern MN into northern/central IA along or just ahead of the eastward-advancing cold front. A rather favorable thermodynamic environment will foster robust updrafts, and any initial supercells should pose a threat for large to very large hail (around 1.5-2.5 inches in diameter). But, a fairly quick transition to more linear structures should occur given the presence of the cold front, with a potentially greater damaging wind threat evolving with eastward extent through the evening before convection eventually weakens. South-southwesterly low-level flow and related shear ahead of the front is not forecast to be overly strong by most guidance this afternoon. But, some threat for a couple of tornadoes remains apparent, especially with any sustained supercells across east-central/southern MN into northern IA late this afternoon/early evening. ...Eastern Kansas into Missouri and Northeast Oklahoma... An upper ridge, with rather warm mid-level temperatures, will remain centered over the southern Plains today. The surface cold front is forecast to continue moving east-southeastward across the mid MO Valley and central Plains through late this afternoon. A surface trough extending southward from this front across the southern High Plains should also mix eastward through peak daytime heating. Given weak large-scale ascent and rather warm mid-level temperatures across this area, there is still a fair amount of uncertainty regarding how many additional thunderstorms will develop later today, notwithstanding the ongoing (mainly elevated) convection over eastern KS and far northwest MO. Still, other surface-based thunderstorms may develop later this afternoon along/near the front/dryline intersection in south-central KS/north-central OK, and along the cold front in eastern KS. While low/mid-level flow should remain fairly modest, steepened low-level lapse rates and moderate instability should support a risk for mainly severe/damaging downdrafts as convection spreads east-southeastward into western MO and northeast OK through this evening. ..Gleason/Moore.. 09/19/2024 Read more

No watches are valid as of Thu Sep 19 16:32:01 UTC 2024.

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...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 1047 AM CDT Thu Sep 19 2024 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. ..Squitieri.. 09/19/2024 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Sep 19 2024/ ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ...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 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Thu Sep 19 2024 Valid 191300Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MINNESOTA...IOWA AND WESTERN WISCONSIN SOUTHWARD INTO EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Scattered severe thunderstorms are possible across central/eastern Minnesota, Iowa, and western Wisconsin. A couple tornadoes, isolated large hail, and damaging winds may occur. An area of locally severe gusts and hail may also develop over parts of eastern Kansas, southwest Missouri, and into northeast Oklahoma. ...Synopsis... Early morning water-vapor imagery shows a slow-moving mid- to upper-level low near the SK/MB/Dakotas border. A negatively tilted shortwave trough will move across the Dakotas and MN through the day. A belt of strong (40-50 kt) 500mb flow will extend through the base of the trough from NE wrapping cyclonically through the Upper MS Valley into western ON and to the northwest of a flattening ridge over the mid MS Valley/southwest Great Lakes. Farther south, weaker west to northwest winds will encompass an area around a southern Plains upper high from KS/OK into MO and AR. In the high levels, flow will be strongest across the central Plains, with weakening winds over the northern Plains/upper MS Valley. In the low levels, a cyclone will develop northeastward from southeast SK into central MB by early Friday morning, while a cold front moves into MN/western IA by mid afternoon, with frontolysis expected during the latter part of the period. A wind shift/surface trough will also extend southward across eastern KS and into northern OK. Ahead of the aforementioned boundaries, southerly flow will maintain a plume of mid to upper 60s F dewpoints. ...MN/IA/WI... Scattered weak, elevated storms from the lower MO Valley northward into MN/WI will gradually move east this morning and likely dissipate by midday. Cloud breaks and clearing in their wake will contribute to appreciable heating and moderate to strong buoyancy developing from near the MO River in western IA northward into MN. Forecast soundings show 2500-3000 J/kg MLCAPE with a veering and strengthening wind profile into the mid levels. A broken band of quasi-discrete storms (including supercells) is forecast to develop from MN southward into at least northern IA. The risk for a couple of tornadoes may be highest from MN into northern IA where effective SRH may exceed 200 m2/s2. A couple of stronger supercells may also develop into western/southwest IA per recent HRRR model trends. Given the northward lifting of the shortwave trough, and increasing inhibition east of the MS River, the primary threat should remain relatively narrow. ...Eastern KS into western MO and into OK... Widely scattered thunderstorms are ongoing this morning from south-central into northeast KS. Much of this activity will likely dissipate but a few residual storms may continue or regenerate on outflow over parts of western MO later this afternoon. Strong heating and the steepening of 0-3 km lapse rates will favor the development of other isolated to widely scattered storms later this afternoon near the wind shift. 12 UTC regional raobs sampled warm mid-level temperatures (around -1 deg C at 525 mb at Norman, OK). These warm midlevel temperatures will limit the overall magnitude of instability. However, lengthy mid to upper level hodographs will support storm organization with any robust/established updraft. The stronger storms will potentially be capable of a risk for severe gusts and perhaps large hail. ..Smith/Mosier.. 09/19/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Sep 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... Some severe potential is evident on both D4/Sunday and D5/Monday. But both regimes appear to be focused on the mesoscale, rendering insufficient predictability at this time frame for a 15 percent highlight. A combination of both low predictability and potential is apparent mid-week next week. A southern-stream shortwave trough is expected to progress from the Southwest into the central Great Plains on D4. A confined belt of enhanced mid-level southwesterlies overspreading a corridor of rich boundary-layer moisture just ahead of an attendant weak surface cyclone may yield a severe-storm threat on Sunday afternoon. Per consensus of latest guidance, the most favored area could be centered around the Lower MO Valley. This shortwave trough may continue northeastward towards the Upper MS Valley into D5. Guidance spread increases with the degree of forward speed, along with potential weakening of the flow fields surrounding the trough. Still, a similar setup may occur on Monday in parts of the Midwest, centered on the southwest Great Lakes region. Mid-level lapse rates on both days are uniformly depicted to be weak, suggestive of lower-end severe potential. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in the southern High Plains. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a 50-65 kt 500-mb jetlet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across eastern NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms should be capable of producing at least isolated severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be curtailed by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential is evident on Saturday afternoon and evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. As such, a severe threat area has not yet been delineated but may be warranted in later outlooks if predictability increases. ..Grams.. 09/19/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Sep 19 2024 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in the southern High Plains. ...Southern High Plains... In advance of a southern-stream shortwave trough reaching the Four Corners, a 50-65 kt 500-mb jetlet is forecast to eject over NM by early evening Saturday. This will yield favorable deep-layer shear for organized storms across eastern NM into parts of northwest TX. Strengthening large-scale ascent within a low-level warm/moist conveyor should overspread this region by Saturday morning. This should yield early-period convection and renders moderate uncertainty over the degree of destabilization by afternoon. Still, with ample boundary-layer heating to the south of early-day activity, a plume of at least weak-surface based buoyancy should develop. Renewed afternoon to early evening thunderstorms should be capable of producing at least isolated severe. Steep mid-level lapse rates should be confined along and west of the Sangre de Cristo Mountains, rendering further uncertainty over the intensity and coverage of the severe threat. The eastern extent of the threat should be curtailed by the confined buoyancy plume and decreasing instability deeper into TX/OK. ...Lower/Mid-MO Valley to the Upper MS Valley... A relatively complex and uncertain evolution to convective potential is evident on Saturday afternoon and evening. This region will largely remain within a low-amplitude mid-level ridge. This may flatten somewhat in between a southern-stream shortwave trough in the Southwest and a northern-stream trough over the southern Prairie Provinces to along the ND/MN international border. In association with the latter wave, a surface cold front should push southeast in the north-central states. Guidance varies with the degree of destabilization ahead of it, and especially with the spatial extent of afternoon/evening convection. As such, a severe threat area has not yet been delineated but may be warranted in later outlooks if predictability increases. ..Grams.. 09/19/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0121 AM CDT Thu Sep 19 2024 Valid 201200Z - 211200Z ...NO CRITICAL AREAS... ...Synopsis... A low-latitude midlevel low will advance eastward across the Lower CO River Valley, while a related belt of strong deep-layer southwesterly flow overspreads the Southwest. Boundary-layer mixing into this strong deep-layer flow will favor dry/breezy conditions across portions of western NM and eastern AZ during the afternoon. While this could lead to locally elevated fire-weather conditions, fuels are generally unsupportive of large-fire spread at this time. Elsewhere, a minimal overlap of breezy surface winds and low RH should limit fire-weather concerns. ..Weinman.. 09/19/2024 ...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 0120 AM CDT Thu Sep 19 2024 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... In the wake of a midlevel low tracking northeastward across Manitoba, strong post-frontal winds will overspread the northern Plains. While these winds may overlap pockets of 25-35 percent RH, cool surface temperatures/marginal RH and recent rainfall should limit the fire-weather threat. Elsewhere, an expansive surface high centered over the western CONUS will limit surface winds and the overall fire-weather risk. ..Weinman.. 09/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more