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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0159 PM CST Tue Mar 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTH-CENTRAL STATES AND THE FL PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible across a portion of the South-Central States into this evening, and across central to south Florida this evening through late tonight. ...20Z Update... Primary change has been to reorient the cat 1-MRGL risk area over the South-Central States in the wake of extensive convection that has largely weakened across LA and MS. Redevelopment should focus on the remnant outflow boundary that arcs northwestward across east TX and intersects a slow-moving front. Relatively greatest potential for sustained development should be across northeast TX to southeast OK, where a few storms may produce isolated large hail. In the wake of extensive overturning, a dearth of downstream instability suggest the severe threat should remain relatively short-lived and wane after dusk. Elevated convection within a weaker sheared environment may persist longer across the Mid-South with small hail being the most likely hazard. No adjustments have been made to the FL risk area, with some convective potential this evening and more probable thunderstorm occurrence overnight. ..Grams.. 03/05/2024 .PREV DISCUSSION... /ISSUED Issued by 15th OWS Scott Air Force Base IL/ ...Synopsis... In mid/upper levels, a low-amplitude, zonal to gently cyclonic flow pattern is present over most of the CONUS, ahead of a synoptic trough over the northeastern Pacific between 130W-140W. That trough will approach coastal northern/central CA near the end of the period with an embedded 500-mb low west of MRY, then move inland on day 2. Downstream, a southern-stream shortwave trough -- with several associated/small-scale vorticity maxima -- was apparent in moisture-channel imagery over eastern parts of OK/TX to the mid/upper TX Coast. This feature is expected to shift eastward across the Gulf Coast States and northern Gulf through the period, reaching parts of MS/AL and the FL Panhandle by 00Z, then moving across GA/FL in piecemeal fashion around the end of the period and early day 2. A weaker perturbation -- initially evident over parts of the Mid-Atlantic region and adjoining ocean waters -- should deamplify as it moves northeastward across New England through tonight. At the surface, a cold front was analyzed at 16Z from western QC across Lake Huron to southern MO, southeastern OK, north-central TX, and the TX South Plains region. A weak, attached low initially east of DAL should drift southward with the boundary and weaken further today, while another frontal-wave low forms ahead of the front over northern AL overnight. The front itself should move slowly southward across central/east TX, AR, and the lower Ohio Valley through the period. ...Arklatex to lower Mississippi Valley/Delta regions... The threat for marginally severe hail is ongoing with widely scattered elevated thunderstorms ongoing over portions of AR into the Arklatex region and nearby LA/east TX. Though predominantly multicellular in character, due to lack of more intense vertical shear, MUCAPE in the 1000-2000 J/kg range, supported by patches of favorable low-level moisture away from convectively modified air masses, should continue to support episodic development generally shifting eastward to east-southeastward across the outlook area into this afternoon. Sporadic large hail on a pulse basis will remain a threat, though isolated damaging to severe gusts cannot be ruled out as well. Several clusters or small complexes of thunderstorms may develop as the morning activity moves toward the lower Mississippi Valley, with the messier mode lessening hail potential locally but maintaining some pulse-wind threat. Strongest mid/upper winds also will be displaced over the Great Lakes and northern Gulf in distinct northern and subtropical streams -- north and south of the greatest concentrations of convection. This should maintain modest deep shear and a mostly multicell mode for inland activity. Though the prefrontal boundary layer should destabilize diurnally, especially over western parts of the outlook area ahead of the cold front -- mid/upper forcing for ascent will be displaced farther east into the Delta region with time -- and ultimately over parts of the Southeast containing less-suitable low-level moisture and instability. Though isolated strong-severe afternoon thunderstorms may form closer to the front in east TX, AR and LA, large-scale subsidence behind the trough will foster stable layers that may inhibit sustained convection over the greatest low-level instability today. With associated coverage uncertainties, overall unconditional severe probabilities are kept at marginal levels for the time being. ...FL... As the large-scale ascent/destabilization passes over the north- central/northeastern Gulf waters -- including the Loop Current -- low/middle-level lapse rates should steepen with weakening MLCINH. This may support upscale organization of convection now near and off the northern coastline into a quasi-linear MCS that would move east-southeastward across the Gulf, reaching the West Coast of FL late this evening or overnight, before shifting eastward over at least parts of the peninsula. Additional convection may form late during the diurnal heating cycle this afternoon, and/or in a zone of increasing warm advection and low-level convergence/lift ahead of the MCS this evening. While both synoptic and convection-allowing guidance is inconsistent on mesoscale timing of the complex, or greatest coverage areas of pre-MCS activity, the general notion of increasing convective potential from late afternoon onward over FL is supported by the pattern and by ongoing offshore convective trends. As such, while the severe threat still looks conditional (especially given some nocturnal stabilization likely to occur inland over FL), at least a marginal unconditional risk now is apparent, given increasing deep shear progged across most of the area, and at least marginal low-level instability with around 500-1500 J/kg MLCAPE away from convective outflows. Progged hodographs generally are not particularly large, though storm-scale and boundary interactions can modify them locally to become more favorable, amidst 35-45-kt effective-shear magnitudes. Read more

MD 0191 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR SOUTHEAST TEXAS TO SOUTHERN LOUISIANA
Mesoscale Discussion 0191 NWS Storm Prediction Center Norman OK 1216 PM CST Tue Mar 05 2024 Areas affected...Far southeast Texas to southern Louisiana Concerning...Severe potential...Watch unlikely Valid 051816Z - 052015Z Probability of Watch Issuance...20 percent SUMMARY...Scattered thunderstorms across southern Louisiana will continue to pose a severe hail risk through the early afternoon hours. This threat is expected to remain sufficiently limited to preclude watch issuance. DISCUSSION...Scattered thunderstorms are ongoing along and just ahead of an outflow boundary across southern LA. Several reports of severe hail (including at least one report of 2 inch hail) have been noted with this activity over the past hour or so. The convective environment is obviously supportive of a severe hail threat, likely owing to ~1500 J/kg MLCAPE with around 30-40 knots of effective bulk shear, and should remain so through early afternoon as storms approach the Gulf coast. However, storm longevity has been limited thus far based on MRMS echo top and VIL imagery. This is likely due to a combination of mean storm motions along the undercutting outflow boundary resulting in destructive storm interactions and somewhat rapid displacement to the cool side of the boundary. Storms developing ahead of the outflow may see slightly longer longevity and pose a more prolonged hail risk. Regardless, the severe threat should wane by mid/late afternoon as the boundary reaches the Gulf Coast, and the limited spatial/temporal duration of the threat limits confidence in the need for a watch. To the west into southeast TX, convective initiation appears less probable in the short term based on satellite trends - likely due to weaker low-level confluence along the boundary. However, the thermodynamic environment is comparatively better than southern LA with lifted indices approaching -10 C. A conditional severe hail/wind risk may materialize if initiation along the boundary can occur. ..Moore/Hart.. 03/05/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LIX...LCH...HGX... LAT...LON 29679348 29659388 29599411 29509433 29489447 29549457 29749477 29949483 30129479 30249463 30259413 30409361 30629294 30849222 30909082 30729045 30509000 30168965 29738958 29378968 29119000 28999041 29039086 29229121 29379137 29469152 29459178 29479208 29459227 29589263 29669310 29679348 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Tue Mar 05 2024 Valid 061200Z - 071200Z The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 03/05/2024 .PREV DISCUSSION... /ISSUED 0147 AM CST Tue Mar 05 2024/ ...Synopsis... A northern-stream midlevel shortwave trough will cross the northern Plains during the afternoon, while a related surface cyclone tracks northeastward from SD across northwestern MN. Along/east of the surface cyclone, a tightening pressure gradient, coupled with shallow boundary-layer mixing into a southerly low-level jet, will yield 20-25 mph sustained southerly surface winds (with gusts upwards of 45 mph) across portions of northeastern NE, eastern SD, far northwest IA, and western MN. While RH reductions will be limited, owing to slightly cool surface temperatures (especially with northward extent), high-resolution ensemble guidance suggests that 25-30 percent minimum RH is possible. As a result, an elevated wind-driven fire-weather risk is expected, given modestly receptive fuels across the region. Farther south, midlevel west-southwesterly flow will strengthen across the southern Rockies -- ahead of midlevel trough/low moving ashore over southern CA. In response, weak lee cyclogenesis is expected over eastern CO, favoring 15-20 mph sustained southwesterly surface winds (with higher gusts) across the southern High Plains. Here, downslope warming/drying will contribute to 15 percent minimum RH, leading to elevated/locally critical fire-weather conditions during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1115 AM CST Tue Mar 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA...AND THE SOUTHERN PLAINS...... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula and the southern Plains. Occasional large hail and gusty winds should be the main threats with this activity. ...Synopsis... An upper trough will move northeastward across the Southeast and Mid-Atlantic on Wednesday. A related, weak surface low is likewise forecast to develop northeastward from GA/SC into NC and southern VA through Wednesday evening. A moist low-level airmass will be in place across these areas ahead of a cold front. Still, greater instability (and isolated severe potential) is generally expected to remain over parts of FL, and offshore over the warmer Gulf Stream waters. Separate areas of thunderstorms may occur through the period across parts of coastal southern CA as an upper trough/low with associated cold mid-level temperatures moves eastward, and across parts of the Great Basin. Weak forecast instability over these regions should limit any appreciable severe threat. ...Central/South Florida... Cool temperatures at mid levels (500 mb temperatures around -10 to -12C) should aid in weak to moderate instability developing across parts of the FL Peninsula through Wednesday afternoon, although the potential for ongoing morning convection may hinder daytime heating to some extent. Still, ascent associated with the upper trough, and a related mid/upper-level jet, should help sustain thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the morning and perhaps early afternoon. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels may support an isolated hail threat with any of the stronger cores that can persist. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates gradually steepen with daytime heating. The potential for redevelopment behind early-day convection appears rather uncertain/conditional, as the better forcing attendant to the upper trough should be moving northeastward and away from the FL Peninsula by Wednesday afternoon. ...Southern/Central Plains... Modest low-level moisture should advance northward across parts of the southern/central Plains through the period as weak cyclogenesis occurs over the southern High Plains. Even though large-scale ascent should remain modest beneath a strong southern-stream mid/ upper-level jet, some guidance suggests that robust convection may develop by late Wednesday afternoon across parts of north-central TX in the vicinity of a weak front/dryline intersection. Around 30-40 kt of deep-layer shear in combination with steepened low/mid-level lapse rates and at least weak instability should support some updraft organization if convection can initiate. Isolated large hail appears possible with the stronger cores, along with occasional severe winds. Have included a Marginal Risk across parts of north-central TX to account for this potential, although the overall threat remains somewhat conditional given nebulous large-scale forcing. Generally elevated convection may also occur across a broader part of the southern/central Plains Wednesday night into early Thursday morning as a southerly low-level jet strengthens across these regions. This activity should remain sub-severe, although small hail appears possible. ..15_ows.. 03/05/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1115 AM CST Tue Mar 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA...AND THE SOUTHERN PLAINS...... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula and the southern Plains. Occasional large hail and gusty winds should be the main threats with this activity. ...Synopsis... An upper trough will move northeastward across the Southeast and Mid-Atlantic on Wednesday. A related, weak surface low is likewise forecast to develop northeastward from GA/SC into NC and southern VA through Wednesday evening. A moist low-level airmass will be in place across these areas ahead of a cold front. Still, greater instability (and isolated severe potential) is generally expected to remain over parts of FL, and offshore over the warmer Gulf Stream waters. Separate areas of thunderstorms may occur through the period across parts of coastal southern CA as an upper trough/low with associated cold mid-level temperatures moves eastward, and across parts of the Great Basin. Weak forecast instability over these regions should limit any appreciable severe threat. ...Central/South Florida... Cool temperatures at mid levels (500 mb temperatures around -10 to -12C) should aid in weak to moderate instability developing across parts of the FL Peninsula through Wednesday afternoon, although the potential for ongoing morning convection may hinder daytime heating to some extent. Still, ascent associated with the upper trough, and a related mid/upper-level jet, should help sustain thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the morning and perhaps early afternoon. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels may support an isolated hail threat with any of the stronger cores that can persist. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates gradually steepen with daytime heating. The potential for redevelopment behind early-day convection appears rather uncertain/conditional, as the better forcing attendant to the upper trough should be moving northeastward and away from the FL Peninsula by Wednesday afternoon. ...Southern/Central Plains... Modest low-level moisture should advance northward across parts of the southern/central Plains through the period as weak cyclogenesis occurs over the southern High Plains. Even though large-scale ascent should remain modest beneath a strong southern-stream mid/ upper-level jet, some guidance suggests that robust convection may develop by late Wednesday afternoon across parts of north-central TX in the vicinity of a weak front/dryline intersection. Around 30-40 kt of deep-layer shear in combination with steepened low/mid-level lapse rates and at least weak instability should support some updraft organization if convection can initiate. Isolated large hail appears possible with the stronger cores, along with occasional severe winds. Have included a Marginal Risk across parts of north-central TX to account for this potential, although the overall threat remains somewhat conditional given nebulous large-scale forcing. Generally elevated convection may also occur across a broader part of the southern/central Plains Wednesday night into early Thursday morning as a southerly low-level jet strengthens across these regions. This activity should remain sub-severe, although small hail appears possible. ..15_ows.. 03/05/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1115 AM CST Tue Mar 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA...AND THE SOUTHERN PLAINS...... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula and the southern Plains. Occasional large hail and gusty winds should be the main threats with this activity. ...Synopsis... An upper trough will move northeastward across the Southeast and Mid-Atlantic on Wednesday. A related, weak surface low is likewise forecast to develop northeastward from GA/SC into NC and southern VA through Wednesday evening. A moist low-level airmass will be in place across these areas ahead of a cold front. Still, greater instability (and isolated severe potential) is generally expected to remain over parts of FL, and offshore over the warmer Gulf Stream waters. Separate areas of thunderstorms may occur through the period across parts of coastal southern CA as an upper trough/low with associated cold mid-level temperatures moves eastward, and across parts of the Great Basin. Weak forecast instability over these regions should limit any appreciable severe threat. ...Central/South Florida... Cool temperatures at mid levels (500 mb temperatures around -10 to -12C) should aid in weak to moderate instability developing across parts of the FL Peninsula through Wednesday afternoon, although the potential for ongoing morning convection may hinder daytime heating to some extent. Still, ascent associated with the upper trough, and a related mid/upper-level jet, should help sustain thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the morning and perhaps early afternoon. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels may support an isolated hail threat with any of the stronger cores that can persist. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates gradually steepen with daytime heating. The potential for redevelopment behind early-day convection appears rather uncertain/conditional, as the better forcing attendant to the upper trough should be moving northeastward and away from the FL Peninsula by Wednesday afternoon. ...Southern/Central Plains... Modest low-level moisture should advance northward across parts of the southern/central Plains through the period as weak cyclogenesis occurs over the southern High Plains. Even though large-scale ascent should remain modest beneath a strong southern-stream mid/ upper-level jet, some guidance suggests that robust convection may develop by late Wednesday afternoon across parts of north-central TX in the vicinity of a weak front/dryline intersection. Around 30-40 kt of deep-layer shear in combination with steepened low/mid-level lapse rates and at least weak instability should support some updraft organization if convection can initiate. Isolated large hail appears possible with the stronger cores, along with occasional severe winds. Have included a Marginal Risk across parts of north-central TX to account for this potential, although the overall threat remains somewhat conditional given nebulous large-scale forcing. Generally elevated convection may also occur across a broader part of the southern/central Plains Wednesday night into early Thursday morning as a southerly low-level jet strengthens across these regions. This activity should remain sub-severe, although small hail appears possible. ..15_ows.. 03/05/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1115 AM CST Tue Mar 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA...AND THE SOUTHERN PLAINS...... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula and the southern Plains. Occasional large hail and gusty winds should be the main threats with this activity. ...Synopsis... An upper trough will move northeastward across the Southeast and Mid-Atlantic on Wednesday. A related, weak surface low is likewise forecast to develop northeastward from GA/SC into NC and southern VA through Wednesday evening. A moist low-level airmass will be in place across these areas ahead of a cold front. Still, greater instability (and isolated severe potential) is generally expected to remain over parts of FL, and offshore over the warmer Gulf Stream waters. Separate areas of thunderstorms may occur through the period across parts of coastal southern CA as an upper trough/low with associated cold mid-level temperatures moves eastward, and across parts of the Great Basin. Weak forecast instability over these regions should limit any appreciable severe threat. ...Central/South Florida... Cool temperatures at mid levels (500 mb temperatures around -10 to -12C) should aid in weak to moderate instability developing across parts of the FL Peninsula through Wednesday afternoon, although the potential for ongoing morning convection may hinder daytime heating to some extent. Still, ascent associated with the upper trough, and a related mid/upper-level jet, should help sustain thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the morning and perhaps early afternoon. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels may support an isolated hail threat with any of the stronger cores that can persist. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates gradually steepen with daytime heating. The potential for redevelopment behind early-day convection appears rather uncertain/conditional, as the better forcing attendant to the upper trough should be moving northeastward and away from the FL Peninsula by Wednesday afternoon. ...Southern/Central Plains... Modest low-level moisture should advance northward across parts of the southern/central Plains through the period as weak cyclogenesis occurs over the southern High Plains. Even though large-scale ascent should remain modest beneath a strong southern-stream mid/ upper-level jet, some guidance suggests that robust convection may develop by late Wednesday afternoon across parts of north-central TX in the vicinity of a weak front/dryline intersection. Around 30-40 kt of deep-layer shear in combination with steepened low/mid-level lapse rates and at least weak instability should support some updraft organization if convection can initiate. Isolated large hail appears possible with the stronger cores, along with occasional severe winds. Have included a Marginal Risk across parts of north-central TX to account for this potential, although the overall threat remains somewhat conditional given nebulous large-scale forcing. Generally elevated convection may also occur across a broader part of the southern/central Plains Wednesday night into early Thursday morning as a southerly low-level jet strengthens across these regions. This activity should remain sub-severe, although small hail appears possible. ..15_ows.. 03/05/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1115 AM CST Tue Mar 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA...AND THE SOUTHERN PLAINS...... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula and the southern Plains. Occasional large hail and gusty winds should be the main threats with this activity. ...Synopsis... An upper trough will move northeastward across the Southeast and Mid-Atlantic on Wednesday. A related, weak surface low is likewise forecast to develop northeastward from GA/SC into NC and southern VA through Wednesday evening. A moist low-level airmass will be in place across these areas ahead of a cold front. Still, greater instability (and isolated severe potential) is generally expected to remain over parts of FL, and offshore over the warmer Gulf Stream waters. Separate areas of thunderstorms may occur through the period across parts of coastal southern CA as an upper trough/low with associated cold mid-level temperatures moves eastward, and across parts of the Great Basin. Weak forecast instability over these regions should limit any appreciable severe threat. ...Central/South Florida... Cool temperatures at mid levels (500 mb temperatures around -10 to -12C) should aid in weak to moderate instability developing across parts of the FL Peninsula through Wednesday afternoon, although the potential for ongoing morning convection may hinder daytime heating to some extent. Still, ascent associated with the upper trough, and a related mid/upper-level jet, should help sustain thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the morning and perhaps early afternoon. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels may support an isolated hail threat with any of the stronger cores that can persist. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates gradually steepen with daytime heating. The potential for redevelopment behind early-day convection appears rather uncertain/conditional, as the better forcing attendant to the upper trough should be moving northeastward and away from the FL Peninsula by Wednesday afternoon. ...Southern/Central Plains... Modest low-level moisture should advance northward across parts of the southern/central Plains through the period as weak cyclogenesis occurs over the southern High Plains. Even though large-scale ascent should remain modest beneath a strong southern-stream mid/ upper-level jet, some guidance suggests that robust convection may develop by late Wednesday afternoon across parts of north-central TX in the vicinity of a weak front/dryline intersection. Around 30-40 kt of deep-layer shear in combination with steepened low/mid-level lapse rates and at least weak instability should support some updraft organization if convection can initiate. Isolated large hail appears possible with the stronger cores, along with occasional severe winds. Have included a Marginal Risk across parts of north-central TX to account for this potential, although the overall threat remains somewhat conditional given nebulous large-scale forcing. Generally elevated convection may also occur across a broader part of the southern/central Plains Wednesday night into early Thursday morning as a southerly low-level jet strengthens across these regions. This activity should remain sub-severe, although small hail appears possible. ..15_ows.. 03/05/2024 Read more