WW 0620 Status Updates
STATUS REPORT ON WW 620 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 NNE LAA TO 45 E AKO TO 45 ENE SNY TO 25 SSW MHN. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1896 ..HALBERT..08/14/24 ATTN...WFO...BOU...GLD...LBF...CYS... STATUS REPORT FOR WS 620 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-063-125-140340- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIT CARSON YUMA KSC023-039-071-109-153-179-181-193-199-203-140340- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GREELEY LOGAN RAWLINS SHERIDAN SHERMAN THOMAS WALLACE WICHITA NEC029-057-063-085-087-101-111-113-117-135-145-140340- NE . NEBRASKA COUNTIES INCLUDED ARE Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0837 PM CDT Tue Aug 13 2024 Valid 140100Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL HIGH PLAINS AND CENTRAL PLAINS INTO MISSOURI... CORRECTED THUNDER LINE IN NORTHERN MONTANA ...SUMMARY... Isolated wind/hail risk will persist for the next few hours from eastern Colorado into southwestern Nebraska and northern Kansas. Some risk for hail/wind may also evolve from central Nebraska southeastward into Missouri. ...Central High Plains eastward to the Middle Missouri Valley, and southeastward into Missouri... An upscale-growing band of strong/severe storms has evolved over the northeastern Colorado vicinity this evening, moving eastward toward southwestern Nebraska and northwestern Kansas. Evening RAOBs and RAP-based objective analyses indicate moderate instability (1000 to 2000 J/kg mixed-layer CAPE), and sufficient shear to allow storms to continue to organize and shift eastward this evening. Along with potential for hail, locally damaging wind gusts in the 60 to 70 MPH range can be expected. Later tonight, a strengthening southwesterly low-level jet across the central Plains and associated ascent may support a separate zone of elevated storm development, where moderate elevated CAPE is expected. With shear sufficient for organized storms, and even a supercell or two, local risk for hail -- and possibly a strong wind gust -- warrants continuation of MRGL risk across this area. ..Goss.. 08/14/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0837 PM CDT Tue Aug 13 2024 Valid 140100Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL HIGH PLAINS AND CENTRAL PLAINS INTO MISSOURI... CORRECTED THUNDER LINE IN NORTHERN MONTANA ...SUMMARY... Isolated wind/hail risk will persist for the next few hours from eastern Colorado into southwestern Nebraska and northern Kansas. Some risk for hail/wind may also evolve from central Nebraska southeastward into Missouri. ...Central High Plains eastward to the Middle Missouri Valley, and southeastward into Missouri... An upscale-growing band of strong/severe storms has evolved over the northeastern Colorado vicinity this evening, moving eastward toward southwestern Nebraska and northwestern Kansas. Evening RAOBs and RAP-based objective analyses indicate moderate instability (1000 to 2000 J/kg mixed-layer CAPE), and sufficient shear to allow storms to continue to organize and shift eastward this evening. Along with potential for hail, locally damaging wind gusts in the 60 to 70 MPH range can be expected. Later tonight, a strengthening southwesterly low-level jet across the central Plains and associated ascent may support a separate zone of elevated storm development, where moderate elevated CAPE is expected. With shear sufficient for organized storms, and even a supercell or two, local risk for hail -- and possibly a strong wind gust -- warrants continuation of MRGL risk across this area. ..Goss.. 08/14/2024 Read more

MD 1894 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN IDAHO...WESTERN WYOMING...NORTHERN UTAH
Mesoscale Discussion 1894 NWS Storm Prediction Center Norman OK 0448 PM CDT Tue Aug 13 2024 Areas affected...Eastern Idaho...Western Wyoming...Northern Utah Concerning...Severe potential...Watch unlikely Valid 132148Z - 140015Z Probability of Watch Issuance...5 percent SUMMARY...An isolated severe threat will likely continue for a few more hours. Hail and gusty winds will be the primary threats. The severe threats should remain too marginal for weather watch issuance is not expected. DISCUSSION...The latest water-vapor imagery and 500 mb RAP analysis suggest that a shortwave trough is moving through the northern Rockies. Lift associated with this feature, is supporting scattered thunderstorm development near a pocket of moderate instability from northern Utah into eastern Idaho. MLCAPE within this area is estimated by the RAP to be in the 1000 to 1500 J/kg range. Mid-level lapse rates are also steep. In addition, the latest WSR-88D at Pocatello, Idaho has 0-6 km shear around 35 knots, with speed shear mostly in the mid-levels. This should be enough for locally strong to severe convection. A rotating storm or two will be possible with hail and gusty winds as the primary threats. The marginal severe threat may persist into the early evening. ..Broyles/Edwards.. 08/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...RIW...TFX...SLC...PIH... LAT...LON 42501262 41431293 40251316 39681288 39571231 39841140 40571059 42001000 43070973 44060967 44440987 44701038 44731090 44581150 44221193 43661227 42871252 42501262 Read more

WW 0620 Status Updates
STATUS FOR WATCH 0620 HAS NOT BEEN ISSUED YET Read more

MD 1892 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHWESTERN MONTANA....WESTERN WYOMING...EASTERN IDAHO AND NORTHERN UTAH
Mesoscale Discussion 1892 NWS Storm Prediction Center Norman OK 0150 PM CDT Tue Aug 13 2024 Areas affected...parts of southwestern Montana....western Wyoming...eastern Idaho and northern Utah Concerning...Severe potential...Watch unlikely Valid 131850Z - 132115Z Probability of Watch Issuance...20 percent SUMMARY...Widely scattered stronger storms will probably continue to develop and intensify through 3-4 PM MDT, with at least a couple becoming severe and posing a risk for large hail and locally damaging wind gusts. Due to the relatively isolated nature of the severe threat, a severe weather watch appears unlikely, but trends will be monitored. DISCUSSION...Precipitable water in excess of 1 inch is advecting northward in a narrow plume, near and to the west of the Wasatch toward the mountains of southwestern Montana. This is occurring in advance of a mid-level trough and embedded cyclonic circulation now progressing east-northeastward across the northern Intermountain Region, and contributing to modest destabilization with daytime heating. Mixed-layer CAPE is now in excess of 1000 J/kg, with large-scale forcing for ascent contributing to weakening inhibition and increasing scattered thunderstorm development. Into and through 21-23Z, a gradual further intensification of storms appears likely, aided by increasingly unstable low-level storm-relative inflow, in the presence of strengthening westerly mid/upper wind fields, including 30-50 kt in the 500-300 mb layer. The evolution of widely scattered supercells is possible, accompanied by a risk for severe hail and locally strong surface gusts. ..Kerr/Mosier.. 08/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...RIW...TFX...SLC...PIH...MSO... LAT...LON 41391352 42421292 43221291 43761314 44321324 44751313 45681217 46021090 45590996 44280975 41801078 40851160 40691295 41391352 Read more

MD 1893 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EAST-CENTRAL COLORADO...FAR SOUTHEAST WYOMING...AND THE NEBRASKA PANHANDLE
Mesoscale Discussion 1893 NWS Storm Prediction Center Norman OK 0342 PM CDT Tue Aug 13 2024 Areas affected...Portions of east-central Colorado...far southeast Wyoming...and the Nebraska Panhandle Concerning...Severe potential...Watch unlikely Valid 132042Z - 132245Z Probability of Watch Issuance...20 percent SUMMARY...Isolated strong to severe thunderstorms capable of producing severe hail and locally damaging gusts are possible this afternoon. The severe threat should eventually increase farther east into this evening. DISCUSSION...Isolated/discrete thunderstorms are evolving along/immediately east of the Colorado Rockies and northward into the Nebraska Panhandle this afternoon, as diurnal heating continues to erode MLCINH along a surface wind shift/lee trough. Over the next couple hours, a few of these storms may intensify and pose a risk of isolated severe hail and locally damaging gusts -- aided by around 30 kt of 0-6 km shear (sampled by DEN VWP and latest ACARS soundings). Overall, weak instability and limited large-scale forcing should limit the severe threat with these initial thunderstorms. With time, thunderstorms should increase in coverage and spread eastward into richer boundary-layer moisture and associated instability -- which should favor an increasing severe risk into this evening. A watch is not expected for the initial thunderstorms developing along/immediately east of the higher terrain in the near-term, though convective trends will be monitored. ..Weinman/Mosier.. 08/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...PUB...BOU...CYS... LAT...LON 38650355 38140329 37670323 37460350 37340384 37410430 37930458 38330473 39600525 40120530 40550522 41310468 41810418 42500349 42440298 42150272 41580283 41100325 40260381 39490387 38650355 Read more

No watches are valid as of Tue Aug 13 20:45:01 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0319 PM CDT Tue Aug 13 2024 Valid 151200Z - 211200Z Fire weather concerns will primarily be limited to portions of the Pacific Northwest and the Great Basin through the remainder of the work week and over the weekend. The general consensus among long-range guidance is that a highly amplified pattern will gradually become established through the weekend with ridging over the central CONUS and troughing along the West Coast. This pattern will maintain dry conditions across CA, NV, and central to western TX with rain/thunderstorm chances elsewhere. Dry fuels across much of the West will support fire weather concerns as a round of isolated to scattered thunderstorms overspreads the Pacific Northwest on Thursday and as winds increase across NV over the weekend. ...D3/Thursday - Pacific Northwest... Isolated to scattered thunderstorms will likely be ongoing at the start of the period (12 UTC Thursday) across portions of OR as a shortwave trough (currently noted in water-vapor imagery off the CA coast) moves across the region. Ensemble guidance continues to show modest probabilities for wetting rainfall (25-50%) and high probability for EL temperatures below -20 C during the 00 UTC Thur to 00 UTC Fri period, suggesting some potential for dry thunderstorms. Given dry fuels already in place across the region, these storms will likely pose a fire weather concern. ...D5/Sat to D6/Sun - Nevada... As the longwave trough becomes established along/off the West Coast, shortwave disturbances embedded within the mean flow will propagate into the Great Basin. Latest ensemble guidance has trended towards slightly stronger waves moving across the region over the weekend, resulting a more robust low-level mass response that should support breezy downslope winds across portions of central NV and maintain very low relative humidity values. Low-end (40%) risk probabilities have been introduced across parts of NV where ensemble guidance shows the highest probability for winds between 15-20 mph. Similar conditions are possible heading into early next week, but confidence in the coverage of such conditions is limited. ...Texas... Hot conditions will gradually become more expansive through the forecast period, especially across central to northern TX where temperatures in excess of 105 F will be common. While the Red River Valley will likely be the southward extent of appreciable rain chances towards the end of the week and into the weekend, parts of central to western TX should remain fairly dry. Several fires have been reported in recent days, and the potential for new starts should increase as temperatures climb and the coverage of available fuels expands. The building upper ridge will modulate surface wind speeds and the overall fire weather threat, but trends will be monitored given the warming/drying trend. ..Moore.. 08/13/2024 ...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 0319 PM CDT Tue Aug 13 2024 Valid 151200Z - 211200Z Fire weather concerns will primarily be limited to portions of the Pacific Northwest and the Great Basin through the remainder of the work week and over the weekend. The general consensus among long-range guidance is that a highly amplified pattern will gradually become established through the weekend with ridging over the central CONUS and troughing along the West Coast. This pattern will maintain dry conditions across CA, NV, and central to western TX with rain/thunderstorm chances elsewhere. Dry fuels across much of the West will support fire weather concerns as a round of isolated to scattered thunderstorms overspreads the Pacific Northwest on Thursday and as winds increase across NV over the weekend. ...D3/Thursday - Pacific Northwest... Isolated to scattered thunderstorms will likely be ongoing at the start of the period (12 UTC Thursday) across portions of OR as a shortwave trough (currently noted in water-vapor imagery off the CA coast) moves across the region. Ensemble guidance continues to show modest probabilities for wetting rainfall (25-50%) and high probability for EL temperatures below -20 C during the 00 UTC Thur to 00 UTC Fri period, suggesting some potential for dry thunderstorms. Given dry fuels already in place across the region, these storms will likely pose a fire weather concern. ...D5/Sat to D6/Sun - Nevada... As the longwave trough becomes established along/off the West Coast, shortwave disturbances embedded within the mean flow will propagate into the Great Basin. Latest ensemble guidance has trended towards slightly stronger waves moving across the region over the weekend, resulting a more robust low-level mass response that should support breezy downslope winds across portions of central NV and maintain very low relative humidity values. Low-end (40%) risk probabilities have been introduced across parts of NV where ensemble guidance shows the highest probability for winds between 15-20 mph. Similar conditions are possible heading into early next week, but confidence in the coverage of such conditions is limited. ...Texas... Hot conditions will gradually become more expansive through the forecast period, especially across central to northern TX where temperatures in excess of 105 F will be common. While the Red River Valley will likely be the southward extent of appreciable rain chances towards the end of the week and into the weekend, parts of central to western TX should remain fairly dry. Several fires have been reported in recent days, and the potential for new starts should increase as temperatures climb and the coverage of available fuels expands. The building upper ridge will modulate surface wind speeds and the overall fire weather threat, but trends will be monitored given the warming/drying trend. ..Moore.. 08/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2024 Valid 132000Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST CO INTO SOUTHWEST NE AND FAR NORTHWEST KS... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening from northeast Colorado into southwest Nebraska and far northwest Kansas. Strong to isolated severe thunderstorms are also possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...20z Update... Adjustments were made to the Day 1 Outlook to remove portions of the Marginal Risk South Carolina behind an ongoing convective line and to introduce 2% tornado probabilities within the Slight Risk across northeast Colorado, southwest Nebraska, and northwest Kansas. Initial cellular development is ongoing across portions of Colorado and Wyoming this afternoon, with potential for strong to severe gusts and large hail. Through the afternoon/evening, evolution of a more organized convective line is expected across northeast Colorado. This line will propagate eastward into NE/KS through the evening. Lee cyclogenesis and mass response will support a strengthening low-level jet and resulting strengthening of low-level shear. The primary threat will be for damaging wind as this line continues eastward into the central Plains overnight. A Marginal Risk continues across the Intermountain West and Northern High Plains, where scattered thunderstorm development is ongoing. Strong to severe gusts and instances of severe hail will possible. ..Thornton/Mosier.. 08/13/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Aug 13 2024/ ...Central High Plains into the Central Plains... Low-amplitude shortwave trough currently moving through the Four Corners vicinity is expected to continue northeastward, helping to support afternoon thunderstorms across the central Rockies. Favorable low-level moisture will exist within the airmass downstream across the central High Plains, characterized by late afternoon dewpoints in the low to mid 60s. Ongoing cloud covered may delay heating a bit, but temperatures are still expected to reach the mid 80s by the late afternoon. These low-level thermodynamic conditions will help remove convective inhibition while also supporting moderate buoyancy. The westerly/southwesterly flow aloft should remain relatively modest (i.e. 20 to 30 kt at 500 mb), but the veering wind profiles expected to be in place will still result in moderate vertical shear. Current expectation is for 0-6 km bulk shear to range from 25 to 35 kt, with the highest values located over northeast CO into western NE. A predominantly multicellular mode is anticipated, with isolated large hail and a damaging gusts possible. The stronger shear over northeast CO suggests a more organized mode is possible here, with the development of a forward-propagating convective line anticipated. Strong gusts will be possible within this line. This line may continue eastward into the central Plains overnight, supported by a moderate low-level jet. ...Lower MO Valley into southeast NE... Ongoing convective complex moving through southwest MO is expected to continue southeastward while gradually weakening. Some re-development is possible during the evening, beginning across southwest MO, as warm-air advection occurs along the remnant outflow. Thunderstorm development should then expand northwestward into northeast KS, northwest MO, and southeast NE as the low-level jet continues to strengthen. Some isolated hail is possible within the strongest storms. Additionally, despite their elevated character, downdrafts could become strong enough to penetrate any low-level stability, with some damaging gusts possible. ...Intermountain West into the northern High Plains... Early-day satellite imagery shows upper ridging centered over the southern Plains and upper troughing from Pacific Northwest into central CA. Moderately enhanced southwesterly flow aloft is in place between these two features, from the Great Basin across much of the Intermountain West and into the northern High Plains. A shortwave trough currently moving through the western Great Basin is expected to progress through this southwesterly flow, reaching the northern High Plains by early Wednesday morning. Favorable moisture is in place ahead of this wave, as evidence by PWATs around 1" sampled by the 12Z soundings at SLC and GJT, with near 0.9" at BOI as well. Scattered to numerous thunderstorms are expected across the region, as northeastward-progressing shortwave trough interacts with this favorable moisture. Ongoing cloud cover and filtered daytime heating is expected to keep temperatures in the upper 70s across much of the region, with slightly warmer temperatures possible across eastern ID and northeastern UT. These temperatures combined with the mid-level moisture already in place will support moderate buoyancy, with the enhanced mid-level flow supporting moderate vertical shear as well. As a result, a largely multicellular mode is anticipated, but a few more organized storms are possible, with occasional bowing segments capable of producing strong gusts. The only exception is across the eastern ID/northeast UT vicinity, where slightly better buoyancy and shear could result in a few supercells. Anticipated isolated coverage currently precludes the need for higher severe probabilities. ...South Carolina... A weak surface low is near the southern SC coast this morning. Modest low-level convergence from this low northwestward into western SC/northeast GA is helping support showers and occasional thunderstorms. This convergence will likely persist throughout the day, with the showers and thunderstorms progressing gradually eastward. A very moist airmass is in place, as evidenced by 16.7 g/kg lowest 100-mb mean mixing ratio on the 12Z CHS sounding, and will diurnally destabilize today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2024 Valid 132000Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST CO INTO SOUTHWEST NE AND FAR NORTHWEST KS... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening from northeast Colorado into southwest Nebraska and far northwest Kansas. Strong to isolated severe thunderstorms are also possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...20z Update... Adjustments were made to the Day 1 Outlook to remove portions of the Marginal Risk South Carolina behind an ongoing convective line and to introduce 2% tornado probabilities within the Slight Risk across northeast Colorado, southwest Nebraska, and northwest Kansas. Initial cellular development is ongoing across portions of Colorado and Wyoming this afternoon, with potential for strong to severe gusts and large hail. Through the afternoon/evening, evolution of a more organized convective line is expected across northeast Colorado. This line will propagate eastward into NE/KS through the evening. Lee cyclogenesis and mass response will support a strengthening low-level jet and resulting strengthening of low-level shear. The primary threat will be for damaging wind as this line continues eastward into the central Plains overnight. A Marginal Risk continues across the Intermountain West and Northern High Plains, where scattered thunderstorm development is ongoing. Strong to severe gusts and instances of severe hail will possible. ..Thornton/Mosier.. 08/13/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Aug 13 2024/ ...Central High Plains into the Central Plains... Low-amplitude shortwave trough currently moving through the Four Corners vicinity is expected to continue northeastward, helping to support afternoon thunderstorms across the central Rockies. Favorable low-level moisture will exist within the airmass downstream across the central High Plains, characterized by late afternoon dewpoints in the low to mid 60s. Ongoing cloud covered may delay heating a bit, but temperatures are still expected to reach the mid 80s by the late afternoon. These low-level thermodynamic conditions will help remove convective inhibition while also supporting moderate buoyancy. The westerly/southwesterly flow aloft should remain relatively modest (i.e. 20 to 30 kt at 500 mb), but the veering wind profiles expected to be in place will still result in moderate vertical shear. Current expectation is for 0-6 km bulk shear to range from 25 to 35 kt, with the highest values located over northeast CO into western NE. A predominantly multicellular mode is anticipated, with isolated large hail and a damaging gusts possible. The stronger shear over northeast CO suggests a more organized mode is possible here, with the development of a forward-propagating convective line anticipated. Strong gusts will be possible within this line. This line may continue eastward into the central Plains overnight, supported by a moderate low-level jet. ...Lower MO Valley into southeast NE... Ongoing convective complex moving through southwest MO is expected to continue southeastward while gradually weakening. Some re-development is possible during the evening, beginning across southwest MO, as warm-air advection occurs along the remnant outflow. Thunderstorm development should then expand northwestward into northeast KS, northwest MO, and southeast NE as the low-level jet continues to strengthen. Some isolated hail is possible within the strongest storms. Additionally, despite their elevated character, downdrafts could become strong enough to penetrate any low-level stability, with some damaging gusts possible. ...Intermountain West into the northern High Plains... Early-day satellite imagery shows upper ridging centered over the southern Plains and upper troughing from Pacific Northwest into central CA. Moderately enhanced southwesterly flow aloft is in place between these two features, from the Great Basin across much of the Intermountain West and into the northern High Plains. A shortwave trough currently moving through the western Great Basin is expected to progress through this southwesterly flow, reaching the northern High Plains by early Wednesday morning. Favorable moisture is in place ahead of this wave, as evidence by PWATs around 1" sampled by the 12Z soundings at SLC and GJT, with near 0.9" at BOI as well. Scattered to numerous thunderstorms are expected across the region, as northeastward-progressing shortwave trough interacts with this favorable moisture. Ongoing cloud cover and filtered daytime heating is expected to keep temperatures in the upper 70s across much of the region, with slightly warmer temperatures possible across eastern ID and northeastern UT. These temperatures combined with the mid-level moisture already in place will support moderate buoyancy, with the enhanced mid-level flow supporting moderate vertical shear as well. As a result, a largely multicellular mode is anticipated, but a few more organized storms are possible, with occasional bowing segments capable of producing strong gusts. The only exception is across the eastern ID/northeast UT vicinity, where slightly better buoyancy and shear could result in a few supercells. Anticipated isolated coverage currently precludes the need for higher severe probabilities. ...South Carolina... A weak surface low is near the southern SC coast this morning. Modest low-level convergence from this low northwestward into western SC/northeast GA is helping support showers and occasional thunderstorms. This convergence will likely persist throughout the day, with the showers and thunderstorms progressing gradually eastward. A very moist airmass is in place, as evidenced by 16.7 g/kg lowest 100-mb mean mixing ratio on the 12Z CHS sounding, and will diurnally destabilize today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/mid Mississippi Valley into parts of the central/southern Plains... Some amplification of a mid/upper-level trough is expected across the upper Midwest/upper MS Valley on Thursday. Within this trough, a mid/upper-level cyclone may develop across parts of MN. A surface low initially over IA/southern MN is forecast to move northeastward, and potentially become occluded as it becomes increasingly colocated with the mid/upper-level low. A cold front attendant to the surface low will move across parts of the upper Midwest into MO/KS. As this occurs, a midlevel jet maximum is forecast to move through the base of the trough from parts of MO/southern IA into IL. In the wake of extensive early-morning convection, moderate low-level southwesterly flow will support airmass recovery and destabilization Thursday afternoon from parts of the east-central Plains into IA/MO/IL. Relatively steep midlevel lapse rates atop rich low-level moisture will support strong to locally extreme buoyancy, with MLCAPE potentially in the 2500-4000 J/kg range across the warm sector by peak heating. Meanwhile, increasing midlevel flow will support effective shear of 40+ kt, resulting in a conditionally favorable severe-thunderstorm environment. The details of convective initiation and evolution remain uncertain, but isolated to widely scattered storms may develop by late afternoon along the primary cold front, and potentially near any remnant outflow boundaries. Supercells with a threat of hail, localized damaging gusts, and a tornado or two will be possible initially, with some upscale growth potentially leading to an increase in damaging-wind potential by Thursday evening, as storms move into parts of southern MO/IL. A few strong to severe storms may also develop within a post-frontal regime from eastern NE into western IA, where lingering low-level moisture will support moderate buoyancy, and deep-layer shear will remain favorable for organized convection during the afternoon/evening. Large hail and localized damaging gusts would be the primary threats in this area. ..Dean.. 08/13/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0126 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z An isolated dry thunderstorm risk area has been introduced for portions of far northern CA into OR. Latest guidance has come into better agreement regarding thunderstorm potential associated with an approaching trough. Thunderstorm chances should increase late afternoon into the overnight/early-morning hours across this region. Forecast soundings have also trended towards drier mid-level conditions with PWAT values between 0.6 to 0.8 inches. Given antecedent dry fuels, dry thunderstorms will be a fire concern. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0157 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1891 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHERN SOUTH CAROLINA
Mesoscale Discussion 1891 NWS Storm Prediction Center Norman OK 1253 PM CDT Tue Aug 13 2024 Areas affected...parts of southern South Carolina Concerning...Severe potential...Watch unlikely Valid 131753Z - 132030Z Probability of Watch Issuance...20 percent SUMMARY...A growing and gradually organizing cluster of storms may pose increasing risk for potentially damaging wind gusts across the South Carolina Lowcountry through 4-6 PM EDT. DISCUSSION...Thunderstorms have recently begun to intensify in a small cluster along a strengthening surface cold pool now south of the Columbia area. This is occurring beneath modest (including around 30 kt near 500 mb) west-northwesterly mid/upper flow, and along a weak south-southwestward advancing front to the lee of the southern Appalachians. The frontal zone extends eastward into coastal areas northeast of Charleston, and is forecast to slowly approach the Savannah area through late afternoon. Although forecast soundings across this region exhibit notable relative warmth, and weak lapse rates, within a layer roughly from 700-500 mb, seasonably high boundary-layer moisture content (including lower/mid 70s F dew points) along the front appears to be contributing to sizable mixed-layer CAPE on the order of 2000+ J/kg with insolation. As modest low-level inflow and lift along the strengthening surface cold pool continue to overcome the inhibition, further upscale convective growth appears possible across the Lowcountry vicinity of South Carolina through 20-22Z. Gradually, this may be accompanied by strengthening rear inflow and potential for strong to severe surface gusts, despite the weak low-level ambient wind fields. ..Kerr/Mosier.. 08/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...CAE... LAT...LON 33598124 33488060 33037966 32538008 32318073 32888151 33418229 33778204 33598124 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF EASTERN NE...WESTERN IA...NORTHEAST KS...NORTHWEST MO... ...SUMMARY... Isolated to scattered severe thunderstorms are possible Wednesday across parts of the northern/central Plains into the mid Missouri Valley, with greater potential for large hail, damaging winds, and a tornado or two across parts of northeast Kansas, eastern Nebraska, western Iowa, and northwest Missouri. ...Eastern NE/northeast KS into parts of IA/MO/southern MN... A mid/upper-level trough will move across the central/northern Great Plains towards the upper Midwest on Wednesday. Multiple vorticity maxima, and possibly one or more MCVs, will likely move through the larger-scale trough. The surface pattern will be similarly complex, with a general consensus for a consolidating surface low somewhere across central NE/KS by afternoon. Outflow and cloudiness from morning convection will influence the position of surface boundaries later in the day. One surface boundary that will serve as an effective warm front is forecast to move northward somewhere across northeast KS/northwest MO into eastern NE/western IA, though its position by afternoon/evening remains uncertain. A weak surface trough/cold front will move across parts of the Dakotas into central NE, with another surface trough potentially moving across KS/southeast NE and intersecting the warm front. Given the rather complex surface/upper-air pattern and influence of morning convection, storm evolution remains rather uncertain Wednesday afternoon and evening. From northeast KS/northwest MO into southeast NE/southwest IA, at least isolated storm development will be possible by late afternoon near the warm front and other surface boundaries. Modestly enhanced southwesterly flow aloft will support effective shear of 30-40 kt, and a couple of supercells could evolve from initial development, with a threat of large hail and damaging wind. Some tornado threat would also accompany any supercells near the warm front, especially into the evening when some increase in low-level flow and SRH is expected. With time, one or more upscale-growing clusters may develop, with an attendant threat of damaging gusts spreading eastward across parts of IA/MO. ...Dakotas into central NE... A few strong to locally severe storms will be possible across parts of the Dakotas into central NE. For the Dakotas, somewhat weaker instability and deep-layer shear is expected compared to areas to the south and east, but at least scattered storm development will be possible in conjunction with the mid/upper-level trough. Depending on the extent of heating/destabilization, isolated hail and strong/damaging gusts will be possible. Across central NE, instability and deep-layer shear may be somewhat stronger, though confidence regarding storm coverage decreases with southward extent. A conditional risk for hail and localized severe gusts will accompany any stronger storm in this area. ...Far eastern ID/UT into WY...northern/eastern CO...western KS...TX/OK Panhandles... Another round of relatively high-based convection appears possible Wednesday afternoon into the early evening from parts of eastern ID/UT into WY and northwest CO. Sufficient instability and modest westerly flow aloft could support a few stronger cells/clusters with strong to locally severe outflow winds. Isolated strong storms will also be possible from eastern CO into western KS, and potentially into the OK/TX Panhandle region. While this area will generally be displaced from stronger large-scale ascent, relatively strong heating, weak to moderate buoyancy, and modest deep-layer flow/shear could support a couple stronger cells/clusters capable of isolated strong/severe gusts and hail. ...Parts of New England... Isolated to widely scattered thunderstorms are possible Wednesday afternoon across parts of New England, along the western periphery of a midlevel low near the Canadian Maritimes. Deep-layer shear will generally be weak, but cold temperatures aloft and unidirectional northerly flow could support a few stronger southward-moving cells/clusters, with small hail and locally gusty winds. Confidence in a more organized severe threat is currently too low for probabilities. ..Dean.. 08/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF EASTERN NE...WESTERN IA...NORTHEAST KS...NORTHWEST MO... ...SUMMARY... Isolated to scattered severe thunderstorms are possible Wednesday across parts of the northern/central Plains into the mid Missouri Valley, with greater potential for large hail, damaging winds, and a tornado or two across parts of northeast Kansas, eastern Nebraska, western Iowa, and northwest Missouri. ...Eastern NE/northeast KS into parts of IA/MO/southern MN... A mid/upper-level trough will move across the central/northern Great Plains towards the upper Midwest on Wednesday. Multiple vorticity maxima, and possibly one or more MCVs, will likely move through the larger-scale trough. The surface pattern will be similarly complex, with a general consensus for a consolidating surface low somewhere across central NE/KS by afternoon. Outflow and cloudiness from morning convection will influence the position of surface boundaries later in the day. One surface boundary that will serve as an effective warm front is forecast to move northward somewhere across northeast KS/northwest MO into eastern NE/western IA, though its position by afternoon/evening remains uncertain. A weak surface trough/cold front will move across parts of the Dakotas into central NE, with another surface trough potentially moving across KS/southeast NE and intersecting the warm front. Given the rather complex surface/upper-air pattern and influence of morning convection, storm evolution remains rather uncertain Wednesday afternoon and evening. From northeast KS/northwest MO into southeast NE/southwest IA, at least isolated storm development will be possible by late afternoon near the warm front and other surface boundaries. Modestly enhanced southwesterly flow aloft will support effective shear of 30-40 kt, and a couple of supercells could evolve from initial development, with a threat of large hail and damaging wind. Some tornado threat would also accompany any supercells near the warm front, especially into the evening when some increase in low-level flow and SRH is expected. With time, one or more upscale-growing clusters may develop, with an attendant threat of damaging gusts spreading eastward across parts of IA/MO. ...Dakotas into central NE... A few strong to locally severe storms will be possible across parts of the Dakotas into central NE. For the Dakotas, somewhat weaker instability and deep-layer shear is expected compared to areas to the south and east, but at least scattered storm development will be possible in conjunction with the mid/upper-level trough. Depending on the extent of heating/destabilization, isolated hail and strong/damaging gusts will be possible. Across central NE, instability and deep-layer shear may be somewhat stronger, though confidence regarding storm coverage decreases with southward extent. A conditional risk for hail and localized severe gusts will accompany any stronger storm in this area. ...Far eastern ID/UT into WY...northern/eastern CO...western KS...TX/OK Panhandles... Another round of relatively high-based convection appears possible Wednesday afternoon into the early evening from parts of eastern ID/UT into WY and northwest CO. Sufficient instability and modest westerly flow aloft could support a few stronger cells/clusters with strong to locally severe outflow winds. Isolated strong storms will also be possible from eastern CO into western KS, and potentially into the OK/TX Panhandle region. While this area will generally be displaced from stronger large-scale ascent, relatively strong heating, weak to moderate buoyancy, and modest deep-layer flow/shear could support a couple stronger cells/clusters capable of isolated strong/severe gusts and hail. ...Parts of New England... Isolated to widely scattered thunderstorms are possible Wednesday afternoon across parts of New England, along the western periphery of a midlevel low near the Canadian Maritimes. Deep-layer shear will generally be weak, but cold temperatures aloft and unidirectional northerly flow could support a few stronger southward-moving cells/clusters, with small hail and locally gusty winds. Confidence in a more organized severe threat is currently too low for probabilities. ..Dean.. 08/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Aug 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST CO INTO SOUTHWEST NE AND FAR NORTHWEST KS... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening from northeast Colorado into southwest Nebraska and far northwest Kansas. Strong to isolated severe thunderstorms are also possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...Central High Plains into the Central Plains... Low-amplitude shortwave trough currently moving through the Four Corners vicinity is expected to continue northeastward, helping to support afternoon thunderstorms across the central Rockies. Favorable low-level moisture will exist within the airmass downstream across the central High Plains, characterized by late afternoon dewpoints in the low to mid 60s. Ongoing cloud covered may delay heating a bit, but temperatures are still expected to reach the mid 80s by the late afternoon. These low-level thermodynamic conditions will help remove convective inhibition while also supporting moderate buoyancy. The westerly/southwesterly flow aloft should remain relatively modest (i.e. 20 to 30 kt at 500 mb), but the veering wind profiles expected to be in place will still result in moderate vertical shear. Current expectation is for 0-6 km bulk shear to range from 25 to 35 kt, with the highest values located over northeast CO into western NE. A predominantly multicellular mode is anticipated, with isolated large hail and a damaging gusts possible. The stronger shear over northeast CO suggests a more organized mode is possible here, with the development of a forward-propagating convective line anticipated. Strong gusts will be possible within this line. This line may continue eastward into the central Plains overnight, supported by a moderate low-level jet. ...Lower MO Valley into southeast NE... Ongoing convective complex moving through southwest MO is expected to continue southeastward while gradually weakening. Some re-development is possible during the evening, beginning across southwest MO, as warm-air advection occurs along the remnant outflow. Thunderstorm development should then expand northwestward into northeast KS, northwest MO, and southeast NE as the low-level jet continues to strengthen. Some isolated hail is possible within the strongest storms. Additionally, despite their elevated character, downdrafts could become strong enough to penetrate any low-level stability, with some damaging gusts possible. ...Intermountain West into the northern High Plains... Early-day satellite imagery shows upper ridging centered over the southern Plains and upper troughing from Pacific Northwest into central CA. Moderately enhanced southwesterly flow aloft is in place between these two features, from the Great Basin across much of the Intermountain West and into the northern High Plains. A shortwave trough currently moving through the western Great Basin is expected to progress through this southwesterly flow, reaching the northern High Plains by early Wednesday morning. Favorable moisture is in place ahead of this wave, as evidence by PWATs around 1" sampled by the 12Z soundings at SLC and GJT, with near 0.9" at BOI as well. Scattered to numerous thunderstorms are expected across the region, as northeastward-progressing shortwave trough interacts with this favorable moisture. Ongoing cloud cover and filtered daytime heating is expected to keep temperatures in the upper 70s across much of the region, with slightly warmer temperatures possible across eastern ID and northeastern UT. These temperatures combined with the mid-level moisture already in place will support moderate buoyancy, with the enhanced mid-level flow supporting moderate vertical shear as well. As a result, a largely multicellular mode is anticipated, but a few more organized storms are possible, with occasional bowing segments capable of producing strong gusts. The only exception is across the eastern ID/northeast UT vicinity, where slightly better buoyancy and shear could result in a few supercells. Anticipated isolated coverage currently precludes the need for higher severe probabilities. ...South Carolina... A weak surface low is near the southern SC coast this morning. Modest low-level convergence from this low northwestward into western SC/northeast GA is helping support showers and occasional thunderstorms. This convergence will likely persist throughout the day, with the showers and thunderstorms progressing gradually eastward. A very moist airmass is in place, as evidenced by 16.7 g/kg lowest 100-mb mean mixing ratio on the 12Z CHS sounding, and will diurnally destabilize today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. ..Mosier/Weinman.. 08/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Aug 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST CO INTO SOUTHWEST NE AND FAR NORTHWEST KS... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening from northeast Colorado into southwest Nebraska and far northwest Kansas. Strong to isolated severe thunderstorms are also possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...Central High Plains into the Central Plains... Low-amplitude shortwave trough currently moving through the Four Corners vicinity is expected to continue northeastward, helping to support afternoon thunderstorms across the central Rockies. Favorable low-level moisture will exist within the airmass downstream across the central High Plains, characterized by late afternoon dewpoints in the low to mid 60s. Ongoing cloud covered may delay heating a bit, but temperatures are still expected to reach the mid 80s by the late afternoon. These low-level thermodynamic conditions will help remove convective inhibition while also supporting moderate buoyancy. The westerly/southwesterly flow aloft should remain relatively modest (i.e. 20 to 30 kt at 500 mb), but the veering wind profiles expected to be in place will still result in moderate vertical shear. Current expectation is for 0-6 km bulk shear to range from 25 to 35 kt, with the highest values located over northeast CO into western NE. A predominantly multicellular mode is anticipated, with isolated large hail and a damaging gusts possible. The stronger shear over northeast CO suggests a more organized mode is possible here, with the development of a forward-propagating convective line anticipated. Strong gusts will be possible within this line. This line may continue eastward into the central Plains overnight, supported by a moderate low-level jet. ...Lower MO Valley into southeast NE... Ongoing convective complex moving through southwest MO is expected to continue southeastward while gradually weakening. Some re-development is possible during the evening, beginning across southwest MO, as warm-air advection occurs along the remnant outflow. Thunderstorm development should then expand northwestward into northeast KS, northwest MO, and southeast NE as the low-level jet continues to strengthen. Some isolated hail is possible within the strongest storms. Additionally, despite their elevated character, downdrafts could become strong enough to penetrate any low-level stability, with some damaging gusts possible. ...Intermountain West into the northern High Plains... Early-day satellite imagery shows upper ridging centered over the southern Plains and upper troughing from Pacific Northwest into central CA. Moderately enhanced southwesterly flow aloft is in place between these two features, from the Great Basin across much of the Intermountain West and into the northern High Plains. A shortwave trough currently moving through the western Great Basin is expected to progress through this southwesterly flow, reaching the northern High Plains by early Wednesday morning. Favorable moisture is in place ahead of this wave, as evidence by PWATs around 1" sampled by the 12Z soundings at SLC and GJT, with near 0.9" at BOI as well. Scattered to numerous thunderstorms are expected across the region, as northeastward-progressing shortwave trough interacts with this favorable moisture. Ongoing cloud cover and filtered daytime heating is expected to keep temperatures in the upper 70s across much of the region, with slightly warmer temperatures possible across eastern ID and northeastern UT. These temperatures combined with the mid-level moisture already in place will support moderate buoyancy, with the enhanced mid-level flow supporting moderate vertical shear as well. As a result, a largely multicellular mode is anticipated, but a few more organized storms are possible, with occasional bowing segments capable of producing strong gusts. The only exception is across the eastern ID/northeast UT vicinity, where slightly better buoyancy and shear could result in a few supercells. Anticipated isolated coverage currently precludes the need for higher severe probabilities. ...South Carolina... A weak surface low is near the southern SC coast this morning. Modest low-level convergence from this low northwestward into western SC/northeast GA is helping support showers and occasional thunderstorms. This convergence will likely persist throughout the day, with the showers and thunderstorms progressing gradually eastward. A very moist airmass is in place, as evidenced by 16.7 g/kg lowest 100-mb mean mixing ratio on the 12Z CHS sounding, and will diurnally destabilize today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. ..Mosier/Weinman.. 08/13/2024 Read more