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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0743 PM CDT Fri Sep 20 2024 Valid 210100Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS REGION AND OVER THE NORTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms remain possible across parts of the central Plains region and the northern High Plains. ...01z Update... Early-evening water-vapor imagery depicts a stubborn upper anticyclone positioned over TX. There is some indication a weak disturbance is flattening the height field a bit over KS, per an elongated cluster of robust convection that extends from west of CNK-SLN-west of ICT. 00z sounding from TOP exhibits seasonally low PW value (1.12 in), but ample 0-6km bulk shear for organized updrafts (40kt). Lower-tropospheric RH is fairly low which may be contributing to strong wind gusts that have been reported with this activity. Until the boundary layer cools later this evening there may be a propensity for locally severe winds with the broken squall line. While LLJ is not expected to be particularly strong, some strengthening in the LLJ is expected over the next few hours across eastern KS and this may allow convection to maintain some intensity through the mid-evening hours. A few strong gusts may also be noted with convection as it spreads east-southeast across northeast MT over the next few hours. 00z sounding from GGW is strongly sheared and lapse rates are steep. While the most robust updrafts are lagging the main wind shift, left exit region of 70kt 500mb jet will translate across this region. Large-scale should contribute to some longevity with this activity as it propagates toward northwest ND. ..Darrow.. 09/21/2024 Read more

MD 2093 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR FROM SOUTH-CENTRAL INTO NORTHEAST KANSAS...AND SMALL PARTS OF NORTHWEST MISSOURI AND FAR SOUTHEAST NEBRASKA
Mesoscale Discussion 2093 NWS Storm Prediction Center Norman OK 0520 PM CDT Fri Sep 20 2024 Areas affected...from south-central into northeast Kansas...and small parts of northwest Missouri and far southeast Nebraska Concerning...Severe potential...Watch possible Valid 202220Z - 210045Z Probability of Watch Issuance...40 percent SUMMARY...Storms over south-central Kansas may persist into the evening in some form and affects locations such as Wichita, Topeka and eventually Kansas City. Strong wind gusts appear to be the primary concern. DISCUSSION...High-based storms have moved from the Panhandles into south-central KS, with some strengthening noted as better moisture is encountered. These storms are on the nose of a hot/low-level lapse rates plume, and close to a warm front draped northwest to southeast across KS. Visible imagery shows other areas of towering CU just east of the ongoing cluster as well, near the KS/OK border, with additional CU fields into north-central KS in the warm advection zone. As the low-level jet increases this evening, the warm front is forecast to shift northward across KS and western MO. This will result in destabilization across areas that are currently stable, and, provide continued support for ascent via warm advection and with outflow boundary interactions. Given the size of the ongoing area of convection, trends will need to be monitored for further strengthening or expansion of wind threat through the evening. ..Jewell/Hart.. 09/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...TOP...ICT...DDC... LAT...LON 38839829 39429704 39619638 39509575 39369541 39149525 38959518 38519507 38139522 37699601 37239723 37229814 37339869 38009887 38579869 38839829 Read more

913
ABPZ20 KNHC 202330
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Fri Sep 20 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Central Portion of the East Pacific:
An area of low pressure could form well to the southwest of the
southwestern coast of Mexico this weekend. Environmental
conditions appear conducive for some slow development of this
system, and a tropical depression could form during the next few
days while it slowly moves generally north to northeastward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Kelly

MD 2093 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR FROM SOUTH-CENTRAL INTO NORTHEAST KANSAS...AND SMALL PARTS OF NORTHWEST MISSOURI AND FAR SOUTHEAST NEBRASKA
Mesoscale Discussion 2093 NWS Storm Prediction Center Norman OK 0520 PM CDT Fri Sep 20 2024 Areas affected...from south-central into northeast Kansas...and small parts of northwest Missouri and far southeast Nebraska Concerning...Severe potential...Watch possible Valid 202220Z - 210045Z Probability of Watch Issuance...40 percent SUMMARY...Storms over south-central Kansas may persist into the evening in some form and affects locations such as Wichita, Topeka and eventually Kansas City. Strong wind gusts appear to be the primary concern. DISCUSSION...High-based storms have moved from the Panhandles into south-central KS, with some strengthening noted as better moisture is encountered. These storms are on the nose of a hot/low-level lapse rates plume, and close to a warm front draped northwest to southeast across KS. Visible imagery shows other areas of towering CU just east of the ongoing cluster as well, near the KS/OK border, with additional CU fields into north-central KS in the warm advection zone. As the low-level jet increases this evening, the warm front is forecast to shift northward across KS and western MO. This will result in destabilization across areas that are currently stable, and, provide continued support for ascent via warm advection and with outflow boundary interactions. Given the size of the ongoing area of convection, trends will need to be monitored for further strengthening or expansion of wind threat through the evening. ..Jewell/Hart.. 09/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...TOP...ICT...DDC... LAT...LON 38839829 39429704 39619638 39509575 39369541 39149525 38959518 38519507 38139522 37699601 37239723 37229814 37339869 38009887 38579869 38839829 Read more

No watches are valid as of Fri Sep 20 22:31:02 UTC 2024.

MD 2091 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF OKLAHOMA...TEXAS...COLORADO AND KANSAS
Mesoscale Discussion 2091 NWS Storm Prediction Center Norman OK 0325 PM CDT Fri Sep 20 2024 Areas affected...Portions of Oklahoma...Texas...Colorado and Kansas Concerning...Severe potential...Watch unlikely Valid 202025Z - 202230Z Probability of Watch Issuance...20 percent SUMMARY...Isolated thunderstorms may increase in coverage and intensity this afternoon and evening. Damaging winds and marginally severe hail are possible with the stronger storms. DISCUSSION...As of 2015 UTC, regional radar imagery showed high-based showers and thunderstorms ongoing over parts of southwest KS and the OK/TX Panhandles. Likely associated with ascent from a weak shortwave trough and front, these storms have persisted in a drier and weakly buoyant air mass through the early afternoon. However, convection should gradually expand northeastward toward a more moist and buoyant air mass (MLCAPE around 1000-1500 J/kg) through the remainder of the afternoon and into this evening. Continued heating and weak ascent will also support additional destabilization and storm development. Area VADs are supportive of some storm organization with 30-35 kt of deep-layer shear. A few stronger/more persistent mutlicells or even marginal supercell structures are possible. Damaging winds appear to be the most likely threat given fairly steep low-level lapse rates and recent reported gusts to 44 kt at KHQG. Increasing buoyancy with eastward extent, and some potential for supercell structures may also support a risk for marginally severe hail with the deeper storms. While storm coverage has so far remained isolated, additional storm development is expected through the afternoon/evening. Still, the limited overlap with buoyancy/deep-layer shear and lack of broader forcing for ascent should keep storm organization and coverage fairly limited. A WW appears unlikely at this time. ..Lyons/Guyer.. 09/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TOP...ICT...OUN...DDC...AMA...PUB... LAT...LON 37080254 37130256 37960175 38520036 39209777 38889640 38259602 37309664 36619858 36300178 36450206 37080254 Read more

MD 2092 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN MONTANA AND NORTH DAKOTA
Mesoscale Discussion 2092 NWS Storm Prediction Center Norman OK 0342 PM CDT Fri Sep 20 2024 Areas affected...portions of northern Montana and North Dakota Concerning...Severe potential...Watch unlikely Valid 202042Z - 202215Z Probability of Watch Issuance...5 percent SUMMARY...Isolated strong to severe gusts are possible with convection near an upper low this afternoon/evening. Storm coverage and the lack of broader organization should keep the threat limited. DISCUSSION...As of 2040 UTC, regional observations showed low-topped showers and thunderstorms ongoing beneath an upper low over parts of northern MT. Cold temperatures aloft (H5 temps ~ -20C) with the upper low are supporting steep low and mid-level lapse rates. Despite poor surface moisture, (dewpoints in the 30s and 40s F) weak buoyancy (~500 J/Kg MUCAPE) should be sufficient to support isolated convection this afternoon and into the early evening hours. The steep lapse rates, and momentum transfer from strong flow aloft will support a risk for strong to severe damaging wind gusts with any storms able to persist. Storm coverage may gradually expand eastward with the upper low as it spreads into northwestern ND. Moisture there is slightly deeper, but buoyancy remains weak. A few strong to severe gusts are possible through the remainder of the afternoon and into the early part of this evening. Given the lack of deeper surface moisture and instability, a WW appears unlikely. ..Lyons/Guyer.. 09/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...GGW...TFX... LAT...LON 48611213 49141268 49341059 49200676 49140335 48760310 48030422 47780567 47750777 48131048 48611213 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0340 PM CDT Fri Sep 20 2024 Valid 221200Z - 281200Z ...Synopsis... By late this weekend through early next week, mid to upper-level troughing is generally expected from the central to eastern CONUS, while ridging impacts the Southwest and Great Basin. This pattern will promote cooler air masses and precipitation chances from the Plains into the Midwest, with warmer and drier conditions west of the Rockies. The latter will likely lead to more receptive fuels developing across the Great Basin, Southwest, and portions of the Pacific Northwest. However, a lack of stronger flow aloft and significant low pressure areas developing will keep the overall fire weather wind threat very low across much of these regions. By mid to late next week, north Pacific mid to upper-level shortwave troughs traversing the western Canadian provinces will result in increasing southwesterly flow through the troposphere over the Pacific Northwest. Confidence in at least elevated fire weather conditions impacting any specific region, however, appears far too low to introduce 40 percent probabilities at this time. ..Barnes.. 09/20/2024 ...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 0254 PM CDT Fri Sep 20 2024 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST...CENTRAL PLAINS...AND NORTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of the Midwest including southwest Lower Michigan, Illinois, and Indiana. Isolated strong to severe storms are also possible across parts of the south-central Plains and the northern High Plains. ...20Z Update... No changes are needed to the ongoing forecast. See the previous discussion for additional details. ..Wendt.. 09/20/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Fri Sep 20 2024/ ...Central Plains... Low-level moisture will advect north-northwestward throughout the day associated with a warm front. As a result, low to mid 60s dewpoints will likely be in place across south-central/southeast KS during the late afternoon. Dewpoints will likely be in upper 50s farther west in southwest KS, with notably drier conditions across the adjacent TX/OK Panhandles where downsloping southwesterly surface winds are likely. Southwesterly flow aloft ahead of the approaching upper low will advect steep mid-level lapse rates northeastward through the southern High Plains into western portions of the central Plains. Modest buoyancy is anticipated during the late afternoon where these lapse rates overlay the more favorable low-level moisture across southern KS. Limited large-scale ascent and low-level confluence near the warm front are anticipated over this region as well, with isolated to widely scattered high-based thunderstorms anticipated. Vertical shear will be modest, but still strong enough for persistent/organized storm structures, and the potential for some strong gusts with the more robust storms. Some isolated hail is also possible over south-central KS where buoyancy is maximized. Low-level moisture will continue advection northward during the evening and overnight, with a strengthening low-level jet anticipated as well. Consequently, additional thunderstorm development is expected after 04Z over northeast KS and adjacent far southeast NE and northwest MO. Isolated hail is possible with the strongest storms. ...Midwest including Illinois/Indiana to Lower Michigan... Upper 60s to low 70s dewpoints are expected from southwest Lower MI southwestward across western IN, southern IL, and southeast MO. Daytime heating of this moist low-level air mass will yield a moderately unstable and uncapped air mass ahead of the approaching front, and thunderstorm development is anticipated as the front interacts with this airmass. Moderate vertical shear will be in place, but poor lapse rates and notable mid-level dry air could make updraft maintenance difficult. A multicellular storm mode is anticipated. Highest storm coverage is expected over southwest Lower MI and western IN, with warm mid-level temperatures tending to limit coverage farther southwest. Locally strong wind gusts will be the primary severe risk, with isolated, marginally severe hail possible as well. ...Northern Montana/northwest North Dakota... At least widely scattered low-topped thunderstorms should develop across northern Montana and/or move into the region from southern Alberta as a cold front moves southeastward. This will be influenced by a southeastward-digging shortwave trough and a related strengthening of cyclonic westerlies within its base. Even with modest overall buoyancy, a diurnal steepening of low-level lapse rates and strengthening low/mid-tropospheric westerlies could potentially yield severe-caliber convectively enhanced wind gusts late this afternoon through around sunset. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Fri Sep 20 2024 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST...CENTRAL PLAINS...AND NORTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of the Midwest including southwest Lower Michigan, Illinois, and Indiana. Isolated strong to severe storms are also possible across parts of the south-central Plains and the northern High Plains. ...20Z Update... No changes are needed to the ongoing forecast. See the previous discussion for additional details. ..Wendt.. 09/20/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Fri Sep 20 2024/ ...Central Plains... Low-level moisture will advect north-northwestward throughout the day associated with a warm front. As a result, low to mid 60s dewpoints will likely be in place across south-central/southeast KS during the late afternoon. Dewpoints will likely be in upper 50s farther west in southwest KS, with notably drier conditions across the adjacent TX/OK Panhandles where downsloping southwesterly surface winds are likely. Southwesterly flow aloft ahead of the approaching upper low will advect steep mid-level lapse rates northeastward through the southern High Plains into western portions of the central Plains. Modest buoyancy is anticipated during the late afternoon where these lapse rates overlay the more favorable low-level moisture across southern KS. Limited large-scale ascent and low-level confluence near the warm front are anticipated over this region as well, with isolated to widely scattered high-based thunderstorms anticipated. Vertical shear will be modest, but still strong enough for persistent/organized storm structures, and the potential for some strong gusts with the more robust storms. Some isolated hail is also possible over south-central KS where buoyancy is maximized. Low-level moisture will continue advection northward during the evening and overnight, with a strengthening low-level jet anticipated as well. Consequently, additional thunderstorm development is expected after 04Z over northeast KS and adjacent far southeast NE and northwest MO. Isolated hail is possible with the strongest storms. ...Midwest including Illinois/Indiana to Lower Michigan... Upper 60s to low 70s dewpoints are expected from southwest Lower MI southwestward across western IN, southern IL, and southeast MO. Daytime heating of this moist low-level air mass will yield a moderately unstable and uncapped air mass ahead of the approaching front, and thunderstorm development is anticipated as the front interacts with this airmass. Moderate vertical shear will be in place, but poor lapse rates and notable mid-level dry air could make updraft maintenance difficult. A multicellular storm mode is anticipated. Highest storm coverage is expected over southwest Lower MI and western IN, with warm mid-level temperatures tending to limit coverage farther southwest. Locally strong wind gusts will be the primary severe risk, with isolated, marginally severe hail possible as well. ...Northern Montana/northwest North Dakota... At least widely scattered low-topped thunderstorms should develop across northern Montana and/or move into the region from southern Alberta as a cold front moves southeastward. This will be influenced by a southeastward-digging shortwave trough and a related strengthening of cyclonic westerlies within its base. Even with modest overall buoyancy, a diurnal steepening of low-level lapse rates and strengthening low/mid-tropospheric westerlies could potentially yield severe-caliber convectively enhanced wind gusts late this afternoon through around sunset. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Fri Sep 20 2024 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST...CENTRAL PLAINS...AND NORTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of the Midwest including southwest Lower Michigan, Illinois, and Indiana. Isolated strong to severe storms are also possible across parts of the south-central Plains and the northern High Plains. ...20Z Update... No changes are needed to the ongoing forecast. See the previous discussion for additional details. ..Wendt.. 09/20/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Fri Sep 20 2024/ ...Central Plains... Low-level moisture will advect north-northwestward throughout the day associated with a warm front. As a result, low to mid 60s dewpoints will likely be in place across south-central/southeast KS during the late afternoon. Dewpoints will likely be in upper 50s farther west in southwest KS, with notably drier conditions across the adjacent TX/OK Panhandles where downsloping southwesterly surface winds are likely. Southwesterly flow aloft ahead of the approaching upper low will advect steep mid-level lapse rates northeastward through the southern High Plains into western portions of the central Plains. Modest buoyancy is anticipated during the late afternoon where these lapse rates overlay the more favorable low-level moisture across southern KS. Limited large-scale ascent and low-level confluence near the warm front are anticipated over this region as well, with isolated to widely scattered high-based thunderstorms anticipated. Vertical shear will be modest, but still strong enough for persistent/organized storm structures, and the potential for some strong gusts with the more robust storms. Some isolated hail is also possible over south-central KS where buoyancy is maximized. Low-level moisture will continue advection northward during the evening and overnight, with a strengthening low-level jet anticipated as well. Consequently, additional thunderstorm development is expected after 04Z over northeast KS and adjacent far southeast NE and northwest MO. Isolated hail is possible with the strongest storms. ...Midwest including Illinois/Indiana to Lower Michigan... Upper 60s to low 70s dewpoints are expected from southwest Lower MI southwestward across western IN, southern IL, and southeast MO. Daytime heating of this moist low-level air mass will yield a moderately unstable and uncapped air mass ahead of the approaching front, and thunderstorm development is anticipated as the front interacts with this airmass. Moderate vertical shear will be in place, but poor lapse rates and notable mid-level dry air could make updraft maintenance difficult. A multicellular storm mode is anticipated. Highest storm coverage is expected over southwest Lower MI and western IN, with warm mid-level temperatures tending to limit coverage farther southwest. Locally strong wind gusts will be the primary severe risk, with isolated, marginally severe hail possible as well. ...Northern Montana/northwest North Dakota... At least widely scattered low-topped thunderstorms should develop across northern Montana and/or move into the region from southern Alberta as a cold front moves southeastward. This will be influenced by a southeastward-digging shortwave trough and a related strengthening of cyclonic westerlies within its base. Even with modest overall buoyancy, a diurnal steepening of low-level lapse rates and strengthening low/mid-tropospheric westerlies could potentially yield severe-caliber convectively enhanced wind gusts late this afternoon through around sunset. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Fri Sep 20 2024 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST...CENTRAL PLAINS...AND NORTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of the Midwest including southwest Lower Michigan, Illinois, and Indiana. Isolated strong to severe storms are also possible across parts of the south-central Plains and the northern High Plains. ...20Z Update... No changes are needed to the ongoing forecast. See the previous discussion for additional details. ..Wendt.. 09/20/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Fri Sep 20 2024/ ...Central Plains... Low-level moisture will advect north-northwestward throughout the day associated with a warm front. As a result, low to mid 60s dewpoints will likely be in place across south-central/southeast KS during the late afternoon. Dewpoints will likely be in upper 50s farther west in southwest KS, with notably drier conditions across the adjacent TX/OK Panhandles where downsloping southwesterly surface winds are likely. Southwesterly flow aloft ahead of the approaching upper low will advect steep mid-level lapse rates northeastward through the southern High Plains into western portions of the central Plains. Modest buoyancy is anticipated during the late afternoon where these lapse rates overlay the more favorable low-level moisture across southern KS. Limited large-scale ascent and low-level confluence near the warm front are anticipated over this region as well, with isolated to widely scattered high-based thunderstorms anticipated. Vertical shear will be modest, but still strong enough for persistent/organized storm structures, and the potential for some strong gusts with the more robust storms. Some isolated hail is also possible over south-central KS where buoyancy is maximized. Low-level moisture will continue advection northward during the evening and overnight, with a strengthening low-level jet anticipated as well. Consequently, additional thunderstorm development is expected after 04Z over northeast KS and adjacent far southeast NE and northwest MO. Isolated hail is possible with the strongest storms. ...Midwest including Illinois/Indiana to Lower Michigan... Upper 60s to low 70s dewpoints are expected from southwest Lower MI southwestward across western IN, southern IL, and southeast MO. Daytime heating of this moist low-level air mass will yield a moderately unstable and uncapped air mass ahead of the approaching front, and thunderstorm development is anticipated as the front interacts with this airmass. Moderate vertical shear will be in place, but poor lapse rates and notable mid-level dry air could make updraft maintenance difficult. A multicellular storm mode is anticipated. Highest storm coverage is expected over southwest Lower MI and western IN, with warm mid-level temperatures tending to limit coverage farther southwest. Locally strong wind gusts will be the primary severe risk, with isolated, marginally severe hail possible as well. ...Northern Montana/northwest North Dakota... At least widely scattered low-topped thunderstorms should develop across northern Montana and/or move into the region from southern Alberta as a cold front moves southeastward. This will be influenced by a southeastward-digging shortwave trough and a related strengthening of cyclonic westerlies within its base. Even with modest overall buoyancy, a diurnal steepening of low-level lapse rates and strengthening low/mid-tropospheric westerlies could potentially yield severe-caliber convectively enhanced wind gusts late this afternoon through around sunset. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Fri Sep 20 2024 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST...CENTRAL PLAINS...AND NORTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of the Midwest including southwest Lower Michigan, Illinois, and Indiana. Isolated strong to severe storms are also possible across parts of the south-central Plains and the northern High Plains. ...20Z Update... No changes are needed to the ongoing forecast. See the previous discussion for additional details. ..Wendt.. 09/20/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Fri Sep 20 2024/ ...Central Plains... Low-level moisture will advect north-northwestward throughout the day associated with a warm front. As a result, low to mid 60s dewpoints will likely be in place across south-central/southeast KS during the late afternoon. Dewpoints will likely be in upper 50s farther west in southwest KS, with notably drier conditions across the adjacent TX/OK Panhandles where downsloping southwesterly surface winds are likely. Southwesterly flow aloft ahead of the approaching upper low will advect steep mid-level lapse rates northeastward through the southern High Plains into western portions of the central Plains. Modest buoyancy is anticipated during the late afternoon where these lapse rates overlay the more favorable low-level moisture across southern KS. Limited large-scale ascent and low-level confluence near the warm front are anticipated over this region as well, with isolated to widely scattered high-based thunderstorms anticipated. Vertical shear will be modest, but still strong enough for persistent/organized storm structures, and the potential for some strong gusts with the more robust storms. Some isolated hail is also possible over south-central KS where buoyancy is maximized. Low-level moisture will continue advection northward during the evening and overnight, with a strengthening low-level jet anticipated as well. Consequently, additional thunderstorm development is expected after 04Z over northeast KS and adjacent far southeast NE and northwest MO. Isolated hail is possible with the strongest storms. ...Midwest including Illinois/Indiana to Lower Michigan... Upper 60s to low 70s dewpoints are expected from southwest Lower MI southwestward across western IN, southern IL, and southeast MO. Daytime heating of this moist low-level air mass will yield a moderately unstable and uncapped air mass ahead of the approaching front, and thunderstorm development is anticipated as the front interacts with this airmass. Moderate vertical shear will be in place, but poor lapse rates and notable mid-level dry air could make updraft maintenance difficult. A multicellular storm mode is anticipated. Highest storm coverage is expected over southwest Lower MI and western IN, with warm mid-level temperatures tending to limit coverage farther southwest. Locally strong wind gusts will be the primary severe risk, with isolated, marginally severe hail possible as well. ...Northern Montana/northwest North Dakota... At least widely scattered low-topped thunderstorms should develop across northern Montana and/or move into the region from southern Alberta as a cold front moves southeastward. This will be influenced by a southeastward-digging shortwave trough and a related strengthening of cyclonic westerlies within its base. Even with modest overall buoyancy, a diurnal steepening of low-level lapse rates and strengthening low/mid-tropospheric westerlies could potentially yield severe-caliber convectively enhanced wind gusts late this afternoon through around sunset. Read more