Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...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 1100 AM CDT Sat Sep 13 2025 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... ...Update... No changes have been made to today's forecast. Please see the previous discussion below for additional details. ..Barnes.. 09/13/2025 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sat Sep 13 2025/ ...Synopsis... The first in a series of mid-level troughs will eject into the Plains states as a second mid-level trough impinges on the West Coast today. Seasonably moist conditions are likely across much of the Interior West, with scattered to numerous thunderstorms likely across the Rockies in association with the first upper trough. The current thinking is that primarily wetting rains may accompany most thunderstorms across the Rockies, resulting in the continued dampening of fuels. As such, no fire weather highlights have been introduced. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 13 2025 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW MEXICO NORTH INTO THE DAKOTAS...AND OVER PORTIONS OF THE MIDWEST... ...SUMMARY... Isolated severe wind and hail will be possible from the Southwest/southern Rockies to the northern Great Plains and a portion of the Midwest, mainly today into early tonight. ...Southwest/southern Rockies/High Plains... An increase in thunderstorm coverage is anticipated from CO south into NM today as ascent/mid-level cooling with the western U.S. upper trough and several embedded vorticity maxima overspread the region. Extensive cloud cover will tend to limit the potential for widespread significant destabilization, with generally modest MLCAPE (at or below 1000 J/kg) over much of the area from CO southward into northern/western NM. Over portions of southern/eastern NM, however, higher surface dew points surging northwest from southwestern TX should help to focus a region of greater instability, with MLCAPE of 1000 to locally near 1500 J/kg possible by afternoon. Ongoing thunderstorms should expand in coverage and increase in intensity as diurnal destabilization occurs, with isolated severe hail and wind possible with the strongest storms. Over southern/eastern NM, deep-layer shear will be more supportive of organized updrafts as a belt of stronger mid-level flow develops near the base of the trough, resulting in elongated hodographs. Here, a somewhat more concentrated risk for severe hail and wind may develop with a couple storms developing supercell structures. Higher severe probabilities were considered for this area, however lingering concerns over the effects of ongoing storms and related cloud cover lowered confidence in increasing probabilities with this outlook. ...NE/SD/ND... Strong storms were ongoing this morning over portions of the western Dakotas in association with embedded impulses in advance of the upper trough. The resulting extensive cloud cover/outflows from multiple rounds of thunderstorms will tend to temper destabilization later today within a modestly-sheared environment. Nevertheless, some isolated severe wind/hail potential will exist as storms over central SD move into ND today. Thunderstorms are expected to redevelop across the central High Plains of NE/northeast CO later this afternoon and evening and move into western SD tonight. Here, sufficient diurnal destabilization in the wake of earlier convection may result in a continued risk for isolated severe storms with strong-damaging gusts and hail. ...IL/IN/WI... A small cluster of thunderstorms over northeast IL/northwest IN, associated with an earlier MCV over WI and ongoing/modest warm advection, is expected to continue moving SSE in the short term across eastern IL/far western IN. Some isolated severe wind and hail potential may develop as this cluster of storms moves along an intensifying instability gradient within a northwest flow regime through at least early afternoon as boundary layer heating commences. ..Bunting/Broyles.. 09/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 13 2025 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW MEXICO NORTH INTO THE DAKOTAS...AND OVER PORTIONS OF THE MIDWEST... ...SUMMARY... Isolated severe wind and hail will be possible from the Southwest/southern Rockies to the northern Great Plains and a portion of the Midwest, mainly today into early tonight. ...Southwest/southern Rockies/High Plains... An increase in thunderstorm coverage is anticipated from CO south into NM today as ascent/mid-level cooling with the western U.S. upper trough and several embedded vorticity maxima overspread the region. Extensive cloud cover will tend to limit the potential for widespread significant destabilization, with generally modest MLCAPE (at or below 1000 J/kg) over much of the area from CO southward into northern/western NM. Over portions of southern/eastern NM, however, higher surface dew points surging northwest from southwestern TX should help to focus a region of greater instability, with MLCAPE of 1000 to locally near 1500 J/kg possible by afternoon. Ongoing thunderstorms should expand in coverage and increase in intensity as diurnal destabilization occurs, with isolated severe hail and wind possible with the strongest storms. Over southern/eastern NM, deep-layer shear will be more supportive of organized updrafts as a belt of stronger mid-level flow develops near the base of the trough, resulting in elongated hodographs. Here, a somewhat more concentrated risk for severe hail and wind may develop with a couple storms developing supercell structures. Higher severe probabilities were considered for this area, however lingering concerns over the effects of ongoing storms and related cloud cover lowered confidence in increasing probabilities with this outlook. ...NE/SD/ND... Strong storms were ongoing this morning over portions of the western Dakotas in association with embedded impulses in advance of the upper trough. The resulting extensive cloud cover/outflows from multiple rounds of thunderstorms will tend to temper destabilization later today within a modestly-sheared environment. Nevertheless, some isolated severe wind/hail potential will exist as storms over central SD move into ND today. Thunderstorms are expected to redevelop across the central High Plains of NE/northeast CO later this afternoon and evening and move into western SD tonight. Here, sufficient diurnal destabilization in the wake of earlier convection may result in a continued risk for isolated severe storms with strong-damaging gusts and hail. ...IL/IN/WI... A small cluster of thunderstorms over northeast IL/northwest IN, associated with an earlier MCV over WI and ongoing/modest warm advection, is expected to continue moving SSE in the short term across eastern IL/far western IN. Some isolated severe wind and hail potential may develop as this cluster of storms moves along an intensifying instability gradient within a northwest flow regime through at least early afternoon as boundary layer heating commences. ..Bunting/Broyles.. 09/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 13 2025 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW MEXICO NORTH INTO THE DAKOTAS...AND OVER PORTIONS OF THE MIDWEST... ...SUMMARY... Isolated severe wind and hail will be possible from the Southwest/southern Rockies to the northern Great Plains and a portion of the Midwest, mainly today into early tonight. ...Southwest/southern Rockies/High Plains... An increase in thunderstorm coverage is anticipated from CO south into NM today as ascent/mid-level cooling with the western U.S. upper trough and several embedded vorticity maxima overspread the region. Extensive cloud cover will tend to limit the potential for widespread significant destabilization, with generally modest MLCAPE (at or below 1000 J/kg) over much of the area from CO southward into northern/western NM. Over portions of southern/eastern NM, however, higher surface dew points surging northwest from southwestern TX should help to focus a region of greater instability, with MLCAPE of 1000 to locally near 1500 J/kg possible by afternoon. Ongoing thunderstorms should expand in coverage and increase in intensity as diurnal destabilization occurs, with isolated severe hail and wind possible with the strongest storms. Over southern/eastern NM, deep-layer shear will be more supportive of organized updrafts as a belt of stronger mid-level flow develops near the base of the trough, resulting in elongated hodographs. Here, a somewhat more concentrated risk for severe hail and wind may develop with a couple storms developing supercell structures. Higher severe probabilities were considered for this area, however lingering concerns over the effects of ongoing storms and related cloud cover lowered confidence in increasing probabilities with this outlook. ...NE/SD/ND... Strong storms were ongoing this morning over portions of the western Dakotas in association with embedded impulses in advance of the upper trough. The resulting extensive cloud cover/outflows from multiple rounds of thunderstorms will tend to temper destabilization later today within a modestly-sheared environment. Nevertheless, some isolated severe wind/hail potential will exist as storms over central SD move into ND today. Thunderstorms are expected to redevelop across the central High Plains of NE/northeast CO later this afternoon and evening and move into western SD tonight. Here, sufficient diurnal destabilization in the wake of earlier convection may result in a continued risk for isolated severe storms with strong-damaging gusts and hail. ...IL/IN/WI... A small cluster of thunderstorms over northeast IL/northwest IN, associated with an earlier MCV over WI and ongoing/modest warm advection, is expected to continue moving SSE in the short term across eastern IL/far western IN. Some isolated severe wind and hail potential may develop as this cluster of storms moves along an intensifying instability gradient within a northwest flow regime through at least early afternoon as boundary layer heating commences. ..Bunting/Broyles.. 09/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 13 2025 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW MEXICO NORTH INTO THE DAKOTAS...AND OVER PORTIONS OF THE MIDWEST... ...SUMMARY... Isolated severe wind and hail will be possible from the Southwest/southern Rockies to the northern Great Plains and a portion of the Midwest, mainly today into early tonight. ...Southwest/southern Rockies/High Plains... An increase in thunderstorm coverage is anticipated from CO south into NM today as ascent/mid-level cooling with the western U.S. upper trough and several embedded vorticity maxima overspread the region. Extensive cloud cover will tend to limit the potential for widespread significant destabilization, with generally modest MLCAPE (at or below 1000 J/kg) over much of the area from CO southward into northern/western NM. Over portions of southern/eastern NM, however, higher surface dew points surging northwest from southwestern TX should help to focus a region of greater instability, with MLCAPE of 1000 to locally near 1500 J/kg possible by afternoon. Ongoing thunderstorms should expand in coverage and increase in intensity as diurnal destabilization occurs, with isolated severe hail and wind possible with the strongest storms. Over southern/eastern NM, deep-layer shear will be more supportive of organized updrafts as a belt of stronger mid-level flow develops near the base of the trough, resulting in elongated hodographs. Here, a somewhat more concentrated risk for severe hail and wind may develop with a couple storms developing supercell structures. Higher severe probabilities were considered for this area, however lingering concerns over the effects of ongoing storms and related cloud cover lowered confidence in increasing probabilities with this outlook. ...NE/SD/ND... Strong storms were ongoing this morning over portions of the western Dakotas in association with embedded impulses in advance of the upper trough. The resulting extensive cloud cover/outflows from multiple rounds of thunderstorms will tend to temper destabilization later today within a modestly-sheared environment. Nevertheless, some isolated severe wind/hail potential will exist as storms over central SD move into ND today. Thunderstorms are expected to redevelop across the central High Plains of NE/northeast CO later this afternoon and evening and move into western SD tonight. Here, sufficient diurnal destabilization in the wake of earlier convection may result in a continued risk for isolated severe storms with strong-damaging gusts and hail. ...IL/IN/WI... A small cluster of thunderstorms over northeast IL/northwest IN, associated with an earlier MCV over WI and ongoing/modest warm advection, is expected to continue moving SSE in the short term across eastern IL/far western IN. Some isolated severe wind and hail potential may develop as this cluster of storms moves along an intensifying instability gradient within a northwest flow regime through at least early afternoon as boundary layer heating commences. ..Bunting/Broyles.. 09/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 13 2025 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW MEXICO NORTH INTO THE DAKOTAS...AND OVER PORTIONS OF THE MIDWEST... ...SUMMARY... Isolated severe wind and hail will be possible from the Southwest/southern Rockies to the northern Great Plains and a portion of the Midwest, mainly today into early tonight. ...Southwest/southern Rockies/High Plains... An increase in thunderstorm coverage is anticipated from CO south into NM today as ascent/mid-level cooling with the western U.S. upper trough and several embedded vorticity maxima overspread the region. Extensive cloud cover will tend to limit the potential for widespread significant destabilization, with generally modest MLCAPE (at or below 1000 J/kg) over much of the area from CO southward into northern/western NM. Over portions of southern/eastern NM, however, higher surface dew points surging northwest from southwestern TX should help to focus a region of greater instability, with MLCAPE of 1000 to locally near 1500 J/kg possible by afternoon. Ongoing thunderstorms should expand in coverage and increase in intensity as diurnal destabilization occurs, with isolated severe hail and wind possible with the strongest storms. Over southern/eastern NM, deep-layer shear will be more supportive of organized updrafts as a belt of stronger mid-level flow develops near the base of the trough, resulting in elongated hodographs. Here, a somewhat more concentrated risk for severe hail and wind may develop with a couple storms developing supercell structures. Higher severe probabilities were considered for this area, however lingering concerns over the effects of ongoing storms and related cloud cover lowered confidence in increasing probabilities with this outlook. ...NE/SD/ND... Strong storms were ongoing this morning over portions of the western Dakotas in association with embedded impulses in advance of the upper trough. The resulting extensive cloud cover/outflows from multiple rounds of thunderstorms will tend to temper destabilization later today within a modestly-sheared environment. Nevertheless, some isolated severe wind/hail potential will exist as storms over central SD move into ND today. Thunderstorms are expected to redevelop across the central High Plains of NE/northeast CO later this afternoon and evening and move into western SD tonight. Here, sufficient diurnal destabilization in the wake of earlier convection may result in a continued risk for isolated severe storms with strong-damaging gusts and hail. ...IL/IN/WI... A small cluster of thunderstorms over northeast IL/northwest IN, associated with an earlier MCV over WI and ongoing/modest warm advection, is expected to continue moving SSE in the short term across eastern IL/far western IN. Some isolated severe wind and hail potential may develop as this cluster of storms moves along an intensifying instability gradient within a northwest flow regime through at least early afternoon as boundary layer heating commences. ..Bunting/Broyles.. 09/13/2025 Read more

000
ABPZ20 KNHC 131200
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sat Sep 13 2025

For the eastern and central North Pacific east of 180 longitude:

Off the coast of Southwestern Mexico:
An area of low pressure could develop well offshore of the coast of
southern or southwestern Mexico early next week. Environmental
conditions are expected to be conducive for gradual development
thereafter, as the low tracks westward to west-northwestward around
10 to 15 mph.
*Formation chance through 48 hours...low...near 0 percent.
*Formation chance through 7 days...low...20 percent.

South of Baja California Peninsula:
An area of low pressure could develop south of the Baja California
Peninsula over the next day or two. Environmental conditions are
expected to be conducive for gradual development thereafter, as the
low tracks slowly westward.
*Formation chance through 48 hours...low...near 0 percent.
*Formation chance through 7 days...low...20 percent.

South and Southeast of the Hawaiian Islands:
An area of low pressure well southeast of the Hawaiian Islands is
producing a large area of disorganized showers and thunderstorms.
Environmental conditions appear conducive for some gradual
development of this system as it moves westward or
west-northwestward at around 10 mph.
*Formation chance through 48 hours...low...near 0 percent.
*Formation chance through 7 days...low...20 percent.

$$
Forecaster Hogsett/Berg

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0254 AM CDT Sat Sep 13 2025 Valid 161200Z - 211200Z ...DISCUSSION... Weak mid/upper-level troughing should continue to move slowly eastward from the northern Rockies/High Plains into the central Plains and Upper Midwest from Day 4/Tuesday into Day 5/Wednesday. Thunderstorms should develop across these regions both days as a surface cold front likewise develops east-southeastward. While moderate to locally strong instability may develop across the warm sector each afternoon, mid-level flow and related deep-layer shear are expected to remain rather modest. This should tend to limit updraft organization and intensity to some extent, although isolated/marginal severe potential may necessitate low severe probabilities in later outlooks. By late next week into the following weekend (Day 6/Thursday to Day 8/Saturday), medium-range guidance begins to diverge in its depiction of the evolution of upper troughing across the Midwest/OH Valley into the eastern CONUS. This lowers confidence in the predictability of organized severe thunderstorms, but some potential for strong thunderstorms may exist across portions of these regions along/ahead of an advancing cold front. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0254 AM CDT Sat Sep 13 2025 Valid 161200Z - 211200Z ...DISCUSSION... Weak mid/upper-level troughing should continue to move slowly eastward from the northern Rockies/High Plains into the central Plains and Upper Midwest from Day 4/Tuesday into Day 5/Wednesday. Thunderstorms should develop across these regions both days as a surface cold front likewise develops east-southeastward. While moderate to locally strong instability may develop across the warm sector each afternoon, mid-level flow and related deep-layer shear are expected to remain rather modest. This should tend to limit updraft organization and intensity to some extent, although isolated/marginal severe potential may necessitate low severe probabilities in later outlooks. By late next week into the following weekend (Day 6/Thursday to Day 8/Saturday), medium-range guidance begins to diverge in its depiction of the evolution of upper troughing across the Midwest/OH Valley into the eastern CONUS. This lowers confidence in the predictability of organized severe thunderstorms, but some potential for strong thunderstorms may exist across portions of these regions along/ahead of an advancing cold front. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0254 AM CDT Sat Sep 13 2025 Valid 161200Z - 211200Z ...DISCUSSION... Weak mid/upper-level troughing should continue to move slowly eastward from the northern Rockies/High Plains into the central Plains and Upper Midwest from Day 4/Tuesday into Day 5/Wednesday. Thunderstorms should develop across these regions both days as a surface cold front likewise develops east-southeastward. While moderate to locally strong instability may develop across the warm sector each afternoon, mid-level flow and related deep-layer shear are expected to remain rather modest. This should tend to limit updraft organization and intensity to some extent, although isolated/marginal severe potential may necessitate low severe probabilities in later outlooks. By late next week into the following weekend (Day 6/Thursday to Day 8/Saturday), medium-range guidance begins to diverge in its depiction of the evolution of upper troughing across the Midwest/OH Valley into the eastern CONUS. This lowers confidence in the predictability of organized severe thunderstorms, but some potential for strong thunderstorms may exist across portions of these regions along/ahead of an advancing cold front. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0254 AM CDT Sat Sep 13 2025 Valid 161200Z - 211200Z ...DISCUSSION... Weak mid/upper-level troughing should continue to move slowly eastward from the northern Rockies/High Plains into the central Plains and Upper Midwest from Day 4/Tuesday into Day 5/Wednesday. Thunderstorms should develop across these regions both days as a surface cold front likewise develops east-southeastward. While moderate to locally strong instability may develop across the warm sector each afternoon, mid-level flow and related deep-layer shear are expected to remain rather modest. This should tend to limit updraft organization and intensity to some extent, although isolated/marginal severe potential may necessitate low severe probabilities in later outlooks. By late next week into the following weekend (Day 6/Thursday to Day 8/Saturday), medium-range guidance begins to diverge in its depiction of the evolution of upper troughing across the Midwest/OH Valley into the eastern CONUS. This lowers confidence in the predictability of organized severe thunderstorms, but some potential for strong thunderstorms may exist across portions of these regions along/ahead of an advancing cold front. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Sat Sep 13 2025 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorm potential appears generally low on Monday. ...Synopsis and Discussion... A pair of upper troughs/lows should be in place over the northern Rockies and northern Plains Monday morning. The lead wave is forecast to advance northward from the Dakotas and MN into central Canada through the day, while the trailing low gradually opens and weakens as it moves slowly eastward over the northern Rockies/High Plains. A weak surface low should develop northward from ND into Manitoba by Monday evening, with a weak front extending southward from this low across parts of the northern/central Plains. Organized severe thunderstorm potential is currently expected to remain fairly limited, with modestly enhanced but meridional/southerly mid/upper-level flow across MN limiting deep-layer shear over the moderately unstable warm sector. Better large-scale ascent is also forecast to gradually shift northward into central Canada through the day as well. Given these potential limiting factors, low severe probabilities have not been included across northern MN and vicinity at this time. Elsewhere, general thunderstorms should occur beneath the upper low across the northern Rockies/High Plains, but both instability and deep-layer shear are forecast to remain weak across these regions. Isolated convection may also develop Monday afternoon and evening with southward extent along a surface lee trough across the southern/central Plains, but weak forcing aloft should tend to limit overall coverage. Other convection may also occur along a low-level moist axis extending from parts of the Ozarks/Mid-South northward into the Upper Midwest. ..Gleason.. 09/13/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Sat Sep 13 2025 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorm potential appears generally low on Monday. ...Synopsis and Discussion... A pair of upper troughs/lows should be in place over the northern Rockies and northern Plains Monday morning. The lead wave is forecast to advance northward from the Dakotas and MN into central Canada through the day, while the trailing low gradually opens and weakens as it moves slowly eastward over the northern Rockies/High Plains. A weak surface low should develop northward from ND into Manitoba by Monday evening, with a weak front extending southward from this low across parts of the northern/central Plains. Organized severe thunderstorm potential is currently expected to remain fairly limited, with modestly enhanced but meridional/southerly mid/upper-level flow across MN limiting deep-layer shear over the moderately unstable warm sector. Better large-scale ascent is also forecast to gradually shift northward into central Canada through the day as well. Given these potential limiting factors, low severe probabilities have not been included across northern MN and vicinity at this time. Elsewhere, general thunderstorms should occur beneath the upper low across the northern Rockies/High Plains, but both instability and deep-layer shear are forecast to remain weak across these regions. Isolated convection may also develop Monday afternoon and evening with southward extent along a surface lee trough across the southern/central Plains, but weak forcing aloft should tend to limit overall coverage. Other convection may also occur along a low-level moist axis extending from parts of the Ozarks/Mid-South northward into the Upper Midwest. ..Gleason.. 09/13/2025 Read more