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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 PM CDT Thu Jun 13 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF CO/KS/NE AND THE NORTHEAST STATES... ...SUMMARY... Scattered severe storms with large hail and wind gusts of 60-80 mph will be possible from mid-afternoon through the evening on Friday along the Front Range to the central Great Plains. Scattered strong storms with sporadic damaging winds and isolated hail will be possible across the Northeast States during the afternoon to early evening. ...CO/KS/NE... Primary categorical change this cycle is to expand the level 2-SLGT risk southward into the more deeply mixed air with thunderstorms expected to develop off the Raton Mesa/Sangre de Cristo Mountains. This includes expansion of the significant severe wind highlight for gusts to around 80 mph. A southern-stream shortwave trough currently off the northern Baja CA coast will reach the Four Corners area by Friday afternoon and progress towards the central High Plains through early Saturday. This feature will likely dampen during the D2 period. The bulk of mid to upper-flow enhancement will be confined along the southern arc of the trough, near/ahead of substantial warming within the southwest quadrant of the trough. As such, the overall kinematic profile will be relatively modest by typical central High Plains standards. But the large-scale forcing for ascent attendant to the approaching trough will support scattered to widespread thunderstorm development during the afternoon off the higher terrain onto the adjacent plains. A quasi-stationary front, modulated by D1 convection, should be draped from the Ozark Plateau west-northwest into the central High Plains. Moderate uncertainty exists with regard to placement of the front in western KS/eastern CO by peak heating, with hot temperatures expected within the deeply mixed air mass to its south. A confined plume of enhanced low-level moisture will be present along and just north of the front emanating west-northwest from the Ozarks. This should support a corridor of MLCAPE from 1500-2500 J/kg amid initially steep mid-level lapse rates. Given the modest deep-layer shear profiles and pervasive convective coverage, a cluster mode should dominate as storms spread onto the High Plains. As they impinge on the greater buoyancy plume/frontal zone, a bowing structure or two may develop as a modestly organized QLCS moves east-northeast into western parts of KS/NE. Scattered severe wind swaths and some hail will be possible, peaking in the late afternoon to dusk. The north and east extent of the threat should slowly wane in both intensity/coverage Friday night. ...New England to the central Appalachians... A series of shortwave impulses embedded within a broader mid/upper trough over ON/QC and the Great Lakes will shift east across the Northeast States through Friday Night. One of these impulses should amplify somewhat as it tracks from the southern Great Plains into NY/PA. A surface cold front should extend from New England southwestward into the OH Valley on Friday afternoon, with a lee trough east of the Appalachians. Mid-level lapse rates will be relatively steeper with northern extent into New England and weaker with southern extent into the Mid-Atlantic States and the central Appalachians. However, deeper boundary-layer warming/mixing is anticipated with southern extent. A broad plume of modest buoyancy with MLCAPE of 500-1500 J/kg is anticipated. Scattered thunderstorms are expected along and ahead of the surface cold front during the afternoon. While the bulk of strong mid to upper-level southwesterly flow should lag behind the boundary and largely parallel it as well, vertical shear will be sufficient for organized cells capable of isolated severe hail and damaging winds across New England. With southern extent, strong gusts within multicell clusters should yield sporadic wind damage. The level 2-SLGT risk corridor in the Northeast represents the relatively more favorable potential for cells/clusters to produce scattered damaging winds and marginally severe hail. ..Grams.. 06/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 PM CDT Thu Jun 13 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF CO/KS/NE AND THE NORTHEAST STATES... ...SUMMARY... Scattered severe storms with large hail and wind gusts of 60-80 mph will be possible from mid-afternoon through the evening on Friday along the Front Range to the central Great Plains. Scattered strong storms with sporadic damaging winds and isolated hail will be possible across the Northeast States during the afternoon to early evening. ...CO/KS/NE... Primary categorical change this cycle is to expand the level 2-SLGT risk southward into the more deeply mixed air with thunderstorms expected to develop off the Raton Mesa/Sangre de Cristo Mountains. This includes expansion of the significant severe wind highlight for gusts to around 80 mph. A southern-stream shortwave trough currently off the northern Baja CA coast will reach the Four Corners area by Friday afternoon and progress towards the central High Plains through early Saturday. This feature will likely dampen during the D2 period. The bulk of mid to upper-flow enhancement will be confined along the southern arc of the trough, near/ahead of substantial warming within the southwest quadrant of the trough. As such, the overall kinematic profile will be relatively modest by typical central High Plains standards. But the large-scale forcing for ascent attendant to the approaching trough will support scattered to widespread thunderstorm development during the afternoon off the higher terrain onto the adjacent plains. A quasi-stationary front, modulated by D1 convection, should be draped from the Ozark Plateau west-northwest into the central High Plains. Moderate uncertainty exists with regard to placement of the front in western KS/eastern CO by peak heating, with hot temperatures expected within the deeply mixed air mass to its south. A confined plume of enhanced low-level moisture will be present along and just north of the front emanating west-northwest from the Ozarks. This should support a corridor of MLCAPE from 1500-2500 J/kg amid initially steep mid-level lapse rates. Given the modest deep-layer shear profiles and pervasive convective coverage, a cluster mode should dominate as storms spread onto the High Plains. As they impinge on the greater buoyancy plume/frontal zone, a bowing structure or two may develop as a modestly organized QLCS moves east-northeast into western parts of KS/NE. Scattered severe wind swaths and some hail will be possible, peaking in the late afternoon to dusk. The north and east extent of the threat should slowly wane in both intensity/coverage Friday night. ...New England to the central Appalachians... A series of shortwave impulses embedded within a broader mid/upper trough over ON/QC and the Great Lakes will shift east across the Northeast States through Friday Night. One of these impulses should amplify somewhat as it tracks from the southern Great Plains into NY/PA. A surface cold front should extend from New England southwestward into the OH Valley on Friday afternoon, with a lee trough east of the Appalachians. Mid-level lapse rates will be relatively steeper with northern extent into New England and weaker with southern extent into the Mid-Atlantic States and the central Appalachians. However, deeper boundary-layer warming/mixing is anticipated with southern extent. A broad plume of modest buoyancy with MLCAPE of 500-1500 J/kg is anticipated. Scattered thunderstorms are expected along and ahead of the surface cold front during the afternoon. While the bulk of strong mid to upper-level southwesterly flow should lag behind the boundary and largely parallel it as well, vertical shear will be sufficient for organized cells capable of isolated severe hail and damaging winds across New England. With southern extent, strong gusts within multicell clusters should yield sporadic wind damage. The level 2-SLGT risk corridor in the Northeast represents the relatively more favorable potential for cells/clusters to produce scattered damaging winds and marginally severe hail. ..Grams.. 06/13/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more