Aggregator

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Sun Oct 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM THE NORTHERN APPALACHIANS INTO PARTS OF THE TENNESSEE VALLEY.... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, from Pennsylvania southward to the Tennessee Valley. Isolated wind damage should be the main threat. ...Central/Southern Appalachians into the Tennessee Valley... Water vapor loop shows a fast-moving and deepening shortwave trough over WI. This feature will dig southeastward across the Great Lakes region through the day, with fast flow aloft extending eastward across the central Appalachians. A surface low currently over northern OH will track eastward across PA along a warm front, while an associated cold front sweeps southeastward across OH/WV/KY/TN. Low-level moisture is quite limited ahead of this system, which will limit coverage and overall intensity of convection. However, over half of morning CAM solutions suggest thunderstorm development along the front this afternoon and evening, where winds aloft and steep low-level lapse rates will promote a risk of locally gusty/damaging winds. The MRGL risk area has been extended northeastward into parts of central/northeast PA, ahead of the surface low and along the warm front. CAPE will be very weak in this area, but forecast soundings and some CAM guidance suggest the potential for 1 or 2 rotating storms capable of gusty wind or perhaps a brief spin-up around peak heating. ..Hart/Weinman.. 10/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Sun Oct 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM THE NORTHERN APPALACHIANS INTO PARTS OF THE TENNESSEE VALLEY.... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, from Pennsylvania southward to the Tennessee Valley. Isolated wind damage should be the main threat. ...Central/Southern Appalachians into the Tennessee Valley... Water vapor loop shows a fast-moving and deepening shortwave trough over WI. This feature will dig southeastward across the Great Lakes region through the day, with fast flow aloft extending eastward across the central Appalachians. A surface low currently over northern OH will track eastward across PA along a warm front, while an associated cold front sweeps southeastward across OH/WV/KY/TN. Low-level moisture is quite limited ahead of this system, which will limit coverage and overall intensity of convection. However, over half of morning CAM solutions suggest thunderstorm development along the front this afternoon and evening, where winds aloft and steep low-level lapse rates will promote a risk of locally gusty/damaging winds. The MRGL risk area has been extended northeastward into parts of central/northeast PA, ahead of the surface low and along the warm front. CAPE will be very weak in this area, but forecast soundings and some CAM guidance suggest the potential for 1 or 2 rotating storms capable of gusty wind or perhaps a brief spin-up around peak heating. ..Hart/Weinman.. 10/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Sun Oct 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM THE NORTHERN APPALACHIANS INTO PARTS OF THE TENNESSEE VALLEY.... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, from Pennsylvania southward to the Tennessee Valley. Isolated wind damage should be the main threat. ...Central/Southern Appalachians into the Tennessee Valley... Water vapor loop shows a fast-moving and deepening shortwave trough over WI. This feature will dig southeastward across the Great Lakes region through the day, with fast flow aloft extending eastward across the central Appalachians. A surface low currently over northern OH will track eastward across PA along a warm front, while an associated cold front sweeps southeastward across OH/WV/KY/TN. Low-level moisture is quite limited ahead of this system, which will limit coverage and overall intensity of convection. However, over half of morning CAM solutions suggest thunderstorm development along the front this afternoon and evening, where winds aloft and steep low-level lapse rates will promote a risk of locally gusty/damaging winds. The MRGL risk area has been extended northeastward into parts of central/northeast PA, ahead of the surface low and along the warm front. CAPE will be very weak in this area, but forecast soundings and some CAM guidance suggest the potential for 1 or 2 rotating storms capable of gusty wind or perhaps a brief spin-up around peak heating. ..Hart/Weinman.. 10/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Sun Oct 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM THE NORTHERN APPALACHIANS INTO PARTS OF THE TENNESSEE VALLEY.... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, from Pennsylvania southward to the Tennessee Valley. Isolated wind damage should be the main threat. ...Central/Southern Appalachians into the Tennessee Valley... Water vapor loop shows a fast-moving and deepening shortwave trough over WI. This feature will dig southeastward across the Great Lakes region through the day, with fast flow aloft extending eastward across the central Appalachians. A surface low currently over northern OH will track eastward across PA along a warm front, while an associated cold front sweeps southeastward across OH/WV/KY/TN. Low-level moisture is quite limited ahead of this system, which will limit coverage and overall intensity of convection. However, over half of morning CAM solutions suggest thunderstorm development along the front this afternoon and evening, where winds aloft and steep low-level lapse rates will promote a risk of locally gusty/damaging winds. The MRGL risk area has been extended northeastward into parts of central/northeast PA, ahead of the surface low and along the warm front. CAPE will be very weak in this area, but forecast soundings and some CAM guidance suggest the potential for 1 or 2 rotating storms capable of gusty wind or perhaps a brief spin-up around peak heating. ..Hart/Weinman.. 10/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Sun Oct 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM THE NORTHERN APPALACHIANS INTO PARTS OF THE TENNESSEE VALLEY.... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, from Pennsylvania southward to the Tennessee Valley. Isolated wind damage should be the main threat. ...Central/Southern Appalachians into the Tennessee Valley... Water vapor loop shows a fast-moving and deepening shortwave trough over WI. This feature will dig southeastward across the Great Lakes region through the day, with fast flow aloft extending eastward across the central Appalachians. A surface low currently over northern OH will track eastward across PA along a warm front, while an associated cold front sweeps southeastward across OH/WV/KY/TN. Low-level moisture is quite limited ahead of this system, which will limit coverage and overall intensity of convection. However, over half of morning CAM solutions suggest thunderstorm development along the front this afternoon and evening, where winds aloft and steep low-level lapse rates will promote a risk of locally gusty/damaging winds. The MRGL risk area has been extended northeastward into parts of central/northeast PA, ahead of the surface low and along the warm front. CAPE will be very weak in this area, but forecast soundings and some CAM guidance suggest the potential for 1 or 2 rotating storms capable of gusty wind or perhaps a brief spin-up around peak heating. ..Hart/Weinman.. 10/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Oct 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, across parts of the central/southern Appalachians and Tennessee Valley. Isolated wind damage and marginally severe hail should be the main threats. ...Central/Southern Appalachians into the Tennessee Valley... Ongoing elevated thunderstorms across northeast OH and western PA should continue eastward this morning in tandem with an enhanced west-southwesterly low-level jet. This activity is expected to outpace low-level moisture return and related destabilization today, and eventually weaken. But in the short term, small hail remains possible. Meanwhile, a vigorous shortwave trough over the Upper Midwest will dig southeastward through the base of a large-scale mid/upper trough, and yield amplification of this trough southward across the Great Lakes through Monday morning. Ascent preceding this shortwave trough will overspread parts of the central/southern Appalachians into the TN Valley, mainly during the evening and overnight. A leading and weaker mid-level perturbation will encourage the primary surface low to develop eastward across PA this afternoon through early evening. A surface cold front will extend southwest of this low into the TN Valley. Convective development along the front appears likely to be delayed until early evening, as the strengthening large-scale ascent aids in increasing low-level convergence along the front amid generally veered flow within the warm sector. Surface dew points should largely range from the mid 50s in WV to a narrow corridor of low 60s in TN, yielding a plume of MLCAPE around 500-1500 J/kg amid initially steep mid-level lapse rates. Recent guidance still differs regarding storm coverage along/ahead of the cold front this evening, from almost none to scattered. This is perhaps in response to the ascent with the shortwave trough strengthening after peak diurnal heating. The strongest 700 mb westerlies (around 40-55 kt) should be confined to mainly northeast of the TN Valley. Forecast hodographs above this level appear small, owing to weakening winds with height as fast mid/upper flow lags to the north-northwest. This suggests supercell structures may struggle to develop/be sustained. But the strong 700 mb flow could support localized damaging winds in any multicell clusters that can form. Farther southwest, somewhat greater buoyancy could foster small to marginally severe hail as well. The overall severe threat appears likely to remain rather isolated, and no changes have been made to the Marginal Risk with this update. ..Gleason/Jewell.. 10/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Oct 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, across parts of the central/southern Appalachians and Tennessee Valley. Isolated wind damage and marginally severe hail should be the main threats. ...Central/Southern Appalachians into the Tennessee Valley... Ongoing elevated thunderstorms across northeast OH and western PA should continue eastward this morning in tandem with an enhanced west-southwesterly low-level jet. This activity is expected to outpace low-level moisture return and related destabilization today, and eventually weaken. But in the short term, small hail remains possible. Meanwhile, a vigorous shortwave trough over the Upper Midwest will dig southeastward through the base of a large-scale mid/upper trough, and yield amplification of this trough southward across the Great Lakes through Monday morning. Ascent preceding this shortwave trough will overspread parts of the central/southern Appalachians into the TN Valley, mainly during the evening and overnight. A leading and weaker mid-level perturbation will encourage the primary surface low to develop eastward across PA this afternoon through early evening. A surface cold front will extend southwest of this low into the TN Valley. Convective development along the front appears likely to be delayed until early evening, as the strengthening large-scale ascent aids in increasing low-level convergence along the front amid generally veered flow within the warm sector. Surface dew points should largely range from the mid 50s in WV to a narrow corridor of low 60s in TN, yielding a plume of MLCAPE around 500-1500 J/kg amid initially steep mid-level lapse rates. Recent guidance still differs regarding storm coverage along/ahead of the cold front this evening, from almost none to scattered. This is perhaps in response to the ascent with the shortwave trough strengthening after peak diurnal heating. The strongest 700 mb westerlies (around 40-55 kt) should be confined to mainly northeast of the TN Valley. Forecast hodographs above this level appear small, owing to weakening winds with height as fast mid/upper flow lags to the north-northwest. This suggests supercell structures may struggle to develop/be sustained. But the strong 700 mb flow could support localized damaging winds in any multicell clusters that can form. Farther southwest, somewhat greater buoyancy could foster small to marginally severe hail as well. The overall severe threat appears likely to remain rather isolated, and no changes have been made to the Marginal Risk with this update. ..Gleason/Jewell.. 10/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Oct 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, across parts of the central/southern Appalachians and Tennessee Valley. Isolated wind damage and marginally severe hail should be the main threats. ...Central/Southern Appalachians into the Tennessee Valley... Ongoing elevated thunderstorms across northeast OH and western PA should continue eastward this morning in tandem with an enhanced west-southwesterly low-level jet. This activity is expected to outpace low-level moisture return and related destabilization today, and eventually weaken. But in the short term, small hail remains possible. Meanwhile, a vigorous shortwave trough over the Upper Midwest will dig southeastward through the base of a large-scale mid/upper trough, and yield amplification of this trough southward across the Great Lakes through Monday morning. Ascent preceding this shortwave trough will overspread parts of the central/southern Appalachians into the TN Valley, mainly during the evening and overnight. A leading and weaker mid-level perturbation will encourage the primary surface low to develop eastward across PA this afternoon through early evening. A surface cold front will extend southwest of this low into the TN Valley. Convective development along the front appears likely to be delayed until early evening, as the strengthening large-scale ascent aids in increasing low-level convergence along the front amid generally veered flow within the warm sector. Surface dew points should largely range from the mid 50s in WV to a narrow corridor of low 60s in TN, yielding a plume of MLCAPE around 500-1500 J/kg amid initially steep mid-level lapse rates. Recent guidance still differs regarding storm coverage along/ahead of the cold front this evening, from almost none to scattered. This is perhaps in response to the ascent with the shortwave trough strengthening after peak diurnal heating. The strongest 700 mb westerlies (around 40-55 kt) should be confined to mainly northeast of the TN Valley. Forecast hodographs above this level appear small, owing to weakening winds with height as fast mid/upper flow lags to the north-northwest. This suggests supercell structures may struggle to develop/be sustained. But the strong 700 mb flow could support localized damaging winds in any multicell clusters that can form. Farther southwest, somewhat greater buoyancy could foster small to marginally severe hail as well. The overall severe threat appears likely to remain rather isolated, and no changes have been made to the Marginal Risk with this update. ..Gleason/Jewell.. 10/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Oct 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, across parts of the central/southern Appalachians and Tennessee Valley. Isolated wind damage and marginally severe hail should be the main threats. ...Central/Southern Appalachians into the Tennessee Valley... Ongoing elevated thunderstorms across northeast OH and western PA should continue eastward this morning in tandem with an enhanced west-southwesterly low-level jet. This activity is expected to outpace low-level moisture return and related destabilization today, and eventually weaken. But in the short term, small hail remains possible. Meanwhile, a vigorous shortwave trough over the Upper Midwest will dig southeastward through the base of a large-scale mid/upper trough, and yield amplification of this trough southward across the Great Lakes through Monday morning. Ascent preceding this shortwave trough will overspread parts of the central/southern Appalachians into the TN Valley, mainly during the evening and overnight. A leading and weaker mid-level perturbation will encourage the primary surface low to develop eastward across PA this afternoon through early evening. A surface cold front will extend southwest of this low into the TN Valley. Convective development along the front appears likely to be delayed until early evening, as the strengthening large-scale ascent aids in increasing low-level convergence along the front amid generally veered flow within the warm sector. Surface dew points should largely range from the mid 50s in WV to a narrow corridor of low 60s in TN, yielding a plume of MLCAPE around 500-1500 J/kg amid initially steep mid-level lapse rates. Recent guidance still differs regarding storm coverage along/ahead of the cold front this evening, from almost none to scattered. This is perhaps in response to the ascent with the shortwave trough strengthening after peak diurnal heating. The strongest 700 mb westerlies (around 40-55 kt) should be confined to mainly northeast of the TN Valley. Forecast hodographs above this level appear small, owing to weakening winds with height as fast mid/upper flow lags to the north-northwest. This suggests supercell structures may struggle to develop/be sustained. But the strong 700 mb flow could support localized damaging winds in any multicell clusters that can form. Farther southwest, somewhat greater buoyancy could foster small to marginally severe hail as well. The overall severe threat appears likely to remain rather isolated, and no changes have been made to the Marginal Risk with this update. ..Gleason/Jewell.. 10/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Oct 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, across parts of the central/southern Appalachians and Tennessee Valley. Isolated wind damage and marginally severe hail should be the main threats. ...Central/Southern Appalachians into the Tennessee Valley... Ongoing elevated thunderstorms across northeast OH and western PA should continue eastward this morning in tandem with an enhanced west-southwesterly low-level jet. This activity is expected to outpace low-level moisture return and related destabilization today, and eventually weaken. But in the short term, small hail remains possible. Meanwhile, a vigorous shortwave trough over the Upper Midwest will dig southeastward through the base of a large-scale mid/upper trough, and yield amplification of this trough southward across the Great Lakes through Monday morning. Ascent preceding this shortwave trough will overspread parts of the central/southern Appalachians into the TN Valley, mainly during the evening and overnight. A leading and weaker mid-level perturbation will encourage the primary surface low to develop eastward across PA this afternoon through early evening. A surface cold front will extend southwest of this low into the TN Valley. Convective development along the front appears likely to be delayed until early evening, as the strengthening large-scale ascent aids in increasing low-level convergence along the front amid generally veered flow within the warm sector. Surface dew points should largely range from the mid 50s in WV to a narrow corridor of low 60s in TN, yielding a plume of MLCAPE around 500-1500 J/kg amid initially steep mid-level lapse rates. Recent guidance still differs regarding storm coverage along/ahead of the cold front this evening, from almost none to scattered. This is perhaps in response to the ascent with the shortwave trough strengthening after peak diurnal heating. The strongest 700 mb westerlies (around 40-55 kt) should be confined to mainly northeast of the TN Valley. Forecast hodographs above this level appear small, owing to weakening winds with height as fast mid/upper flow lags to the north-northwest. This suggests supercell structures may struggle to develop/be sustained. But the strong 700 mb flow could support localized damaging winds in any multicell clusters that can form. Farther southwest, somewhat greater buoyancy could foster small to marginally severe hail as well. The overall severe threat appears likely to remain rather isolated, and no changes have been made to the Marginal Risk with this update. ..Gleason/Jewell.. 10/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sun Oct 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...SUMMARY... Strong to locally severe thunderstorms are possible, mainly this evening, across parts of the central/southern Appalachians and Tennessee Valley. Isolated wind damage and marginally severe hail should be the main threats. ...Central/Southern Appalachians into the Tennessee Valley... Ongoing elevated thunderstorms across northeast OH and western PA should continue eastward this morning in tandem with an enhanced west-southwesterly low-level jet. This activity is expected to outpace low-level moisture return and related destabilization today, and eventually weaken. But in the short term, small hail remains possible. Meanwhile, a vigorous shortwave trough over the Upper Midwest will dig southeastward through the base of a large-scale mid/upper trough, and yield amplification of this trough southward across the Great Lakes through Monday morning. Ascent preceding this shortwave trough will overspread parts of the central/southern Appalachians into the TN Valley, mainly during the evening and overnight. A leading and weaker mid-level perturbation will encourage the primary surface low to develop eastward across PA this afternoon through early evening. A surface cold front will extend southwest of this low into the TN Valley. Convective development along the front appears likely to be delayed until early evening, as the strengthening large-scale ascent aids in increasing low-level convergence along the front amid generally veered flow within the warm sector. Surface dew points should largely range from the mid 50s in WV to a narrow corridor of low 60s in TN, yielding a plume of MLCAPE around 500-1500 J/kg amid initially steep mid-level lapse rates. Recent guidance still differs regarding storm coverage along/ahead of the cold front this evening, from almost none to scattered. This is perhaps in response to the ascent with the shortwave trough strengthening after peak diurnal heating. The strongest 700 mb westerlies (around 40-55 kt) should be confined to mainly northeast of the TN Valley. Forecast hodographs above this level appear small, owing to weakening winds with height as fast mid/upper flow lags to the north-northwest. This suggests supercell structures may struggle to develop/be sustained. But the strong 700 mb flow could support localized damaging winds in any multicell clusters that can form. Farther southwest, somewhat greater buoyancy could foster small to marginally severe hail as well. The overall severe threat appears likely to remain rather isolated, and no changes have been made to the Marginal Risk with this update. ..Gleason/Jewell.. 10/13/2024 Read more

000
ABPZ20 KNHC 131137
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sun Oct 13 2024

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

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Konarik/Papin

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Oct 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Initially amplified mid-level troughing near the Atlantic Seaboard is forecast to shift offshore and lose amplitude across the western Atlantic during the middle to latter portion of the coming work week. In its wake, medium-range guidance indicates at least a couple of significant short wave perturbations will emerge from a somewhat more progressive regime across the mid-latitude latitude Pacific. It still appears that the lead perturbation may provide support for strong surface cyclogenesis to the lee of the Canadian and northern U.S. Rockies during the latter portion of this week. While there is variance among the models concerning early evolution south of the international border, primary cyclone development is appearing most probable across the Canadian Prairies into higher latitudes of interior Canada. As this occurs, a trailing cold front may overtake modestly deep surface troughing across the northern into central U.S. Great Plains Thursday into Friday. This could become a focus for a corridor of increasing thunderstorm development. However, it still appears that rather modest to weak low-level moisture return, in the wake of a prior cool/dry intrusion as far south as the northern Gulf of Mexico, will tend to limit destabilization and minimize the risk for severe storms. Models indicate that the second impulse, quickly progressing inland behind the lead wave, will tend to split off toward the southern mid-latitudes. However, the differences between the ECENS/ECMWF and GEFS/GFS remain quite large concerning the amplification and progressiveness of this perturbation across the central/southern U.S. late this week into next weekend. Even so, with low-level moisture return off the Gulf of Mexico initially limited, and then perhaps impeded by the progression of the lead system, it is not clear whether these differences will have much impact on the overall convective potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Oct 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Initially amplified mid-level troughing near the Atlantic Seaboard is forecast to shift offshore and lose amplitude across the western Atlantic during the middle to latter portion of the coming work week. In its wake, medium-range guidance indicates at least a couple of significant short wave perturbations will emerge from a somewhat more progressive regime across the mid-latitude latitude Pacific. It still appears that the lead perturbation may provide support for strong surface cyclogenesis to the lee of the Canadian and northern U.S. Rockies during the latter portion of this week. While there is variance among the models concerning early evolution south of the international border, primary cyclone development is appearing most probable across the Canadian Prairies into higher latitudes of interior Canada. As this occurs, a trailing cold front may overtake modestly deep surface troughing across the northern into central U.S. Great Plains Thursday into Friday. This could become a focus for a corridor of increasing thunderstorm development. However, it still appears that rather modest to weak low-level moisture return, in the wake of a prior cool/dry intrusion as far south as the northern Gulf of Mexico, will tend to limit destabilization and minimize the risk for severe storms. Models indicate that the second impulse, quickly progressing inland behind the lead wave, will tend to split off toward the southern mid-latitudes. However, the differences between the ECENS/ECMWF and GEFS/GFS remain quite large concerning the amplification and progressiveness of this perturbation across the central/southern U.S. late this week into next weekend. Even so, with low-level moisture return off the Gulf of Mexico initially limited, and then perhaps impeded by the progression of the lead system, it is not clear whether these differences will have much impact on the overall convective potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Oct 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Initially amplified mid-level troughing near the Atlantic Seaboard is forecast to shift offshore and lose amplitude across the western Atlantic during the middle to latter portion of the coming work week. In its wake, medium-range guidance indicates at least a couple of significant short wave perturbations will emerge from a somewhat more progressive regime across the mid-latitude latitude Pacific. It still appears that the lead perturbation may provide support for strong surface cyclogenesis to the lee of the Canadian and northern U.S. Rockies during the latter portion of this week. While there is variance among the models concerning early evolution south of the international border, primary cyclone development is appearing most probable across the Canadian Prairies into higher latitudes of interior Canada. As this occurs, a trailing cold front may overtake modestly deep surface troughing across the northern into central U.S. Great Plains Thursday into Friday. This could become a focus for a corridor of increasing thunderstorm development. However, it still appears that rather modest to weak low-level moisture return, in the wake of a prior cool/dry intrusion as far south as the northern Gulf of Mexico, will tend to limit destabilization and minimize the risk for severe storms. Models indicate that the second impulse, quickly progressing inland behind the lead wave, will tend to split off toward the southern mid-latitudes. However, the differences between the ECENS/ECMWF and GEFS/GFS remain quite large concerning the amplification and progressiveness of this perturbation across the central/southern U.S. late this week into next weekend. Even so, with low-level moisture return off the Gulf of Mexico initially limited, and then perhaps impeded by the progression of the lead system, it is not clear whether these differences will have much impact on the overall convective potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Oct 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Initially amplified mid-level troughing near the Atlantic Seaboard is forecast to shift offshore and lose amplitude across the western Atlantic during the middle to latter portion of the coming work week. In its wake, medium-range guidance indicates at least a couple of significant short wave perturbations will emerge from a somewhat more progressive regime across the mid-latitude latitude Pacific. It still appears that the lead perturbation may provide support for strong surface cyclogenesis to the lee of the Canadian and northern U.S. Rockies during the latter portion of this week. While there is variance among the models concerning early evolution south of the international border, primary cyclone development is appearing most probable across the Canadian Prairies into higher latitudes of interior Canada. As this occurs, a trailing cold front may overtake modestly deep surface troughing across the northern into central U.S. Great Plains Thursday into Friday. This could become a focus for a corridor of increasing thunderstorm development. However, it still appears that rather modest to weak low-level moisture return, in the wake of a prior cool/dry intrusion as far south as the northern Gulf of Mexico, will tend to limit destabilization and minimize the risk for severe storms. Models indicate that the second impulse, quickly progressing inland behind the lead wave, will tend to split off toward the southern mid-latitudes. However, the differences between the ECENS/ECMWF and GEFS/GFS remain quite large concerning the amplification and progressiveness of this perturbation across the central/southern U.S. late this week into next weekend. Even so, with low-level moisture return off the Gulf of Mexico initially limited, and then perhaps impeded by the progression of the lead system, it is not clear whether these differences will have much impact on the overall convective potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Oct 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Initially amplified mid-level troughing near the Atlantic Seaboard is forecast to shift offshore and lose amplitude across the western Atlantic during the middle to latter portion of the coming work week. In its wake, medium-range guidance indicates at least a couple of significant short wave perturbations will emerge from a somewhat more progressive regime across the mid-latitude latitude Pacific. It still appears that the lead perturbation may provide support for strong surface cyclogenesis to the lee of the Canadian and northern U.S. Rockies during the latter portion of this week. While there is variance among the models concerning early evolution south of the international border, primary cyclone development is appearing most probable across the Canadian Prairies into higher latitudes of interior Canada. As this occurs, a trailing cold front may overtake modestly deep surface troughing across the northern into central U.S. Great Plains Thursday into Friday. This could become a focus for a corridor of increasing thunderstorm development. However, it still appears that rather modest to weak low-level moisture return, in the wake of a prior cool/dry intrusion as far south as the northern Gulf of Mexico, will tend to limit destabilization and minimize the risk for severe storms. Models indicate that the second impulse, quickly progressing inland behind the lead wave, will tend to split off toward the southern mid-latitudes. However, the differences between the ECENS/ECMWF and GEFS/GFS remain quite large concerning the amplification and progressiveness of this perturbation across the central/southern U.S. late this week into next weekend. Even so, with low-level moisture return off the Gulf of Mexico initially limited, and then perhaps impeded by the progression of the lead system, it is not clear whether these differences will have much impact on the overall convective potential. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0139 AM CDT Sun Oct 13 2024 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the U.S. Tuesday through Tuesday night. ...Discussion... Large-scale mid-level troughing appears likely to continue to gradually amplify across the eastern U.S. Tuesday through Tuesday night. As a significant embedded short wave impulse digs southeast of the lower Missouri and Ohio Valleys, peak amplitude may be reached near the Atlantic Seaboard around or after 12Z Wednesday. In its wake, cool surface ridging is likely to encompass much of the interior U.S. into northern Gulf of Mexico and southern Atlantic Seaboard. However, surface cyclogenesis may commence to the immediate lee of the Canadian and northern U.S. Rockies by late Tuesday night, as a significant mid-level trough, on the leading edge of a somewhat more progressive regime emerging from the mid-latitude Pacific, approaches the British Columbia/Pacific Northwest coast. Beneath the mid-level cold core (including 500 mb temperatures below -30C) shifting across the Ohio Valley during the day, and another remnant pocket of cold air aloft across the Four Corners vicinity, diurnal convective development might become capable of producing occasional lightning. Otherwise, relatively dry and/or stable conditions appear likely to continue to prevail across much of the U.S. through this period. ..Kerr.. 10/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0139 AM CDT Sun Oct 13 2024 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the U.S. Tuesday through Tuesday night. ...Discussion... Large-scale mid-level troughing appears likely to continue to gradually amplify across the eastern U.S. Tuesday through Tuesday night. As a significant embedded short wave impulse digs southeast of the lower Missouri and Ohio Valleys, peak amplitude may be reached near the Atlantic Seaboard around or after 12Z Wednesday. In its wake, cool surface ridging is likely to encompass much of the interior U.S. into northern Gulf of Mexico and southern Atlantic Seaboard. However, surface cyclogenesis may commence to the immediate lee of the Canadian and northern U.S. Rockies by late Tuesday night, as a significant mid-level trough, on the leading edge of a somewhat more progressive regime emerging from the mid-latitude Pacific, approaches the British Columbia/Pacific Northwest coast. Beneath the mid-level cold core (including 500 mb temperatures below -30C) shifting across the Ohio Valley during the day, and another remnant pocket of cold air aloft across the Four Corners vicinity, diurnal convective development might become capable of producing occasional lightning. Otherwise, relatively dry and/or stable conditions appear likely to continue to prevail across much of the U.S. through this period. ..Kerr.. 10/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0139 AM CDT Sun Oct 13 2024 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the U.S. Tuesday through Tuesday night. ...Discussion... Large-scale mid-level troughing appears likely to continue to gradually amplify across the eastern U.S. Tuesday through Tuesday night. As a significant embedded short wave impulse digs southeast of the lower Missouri and Ohio Valleys, peak amplitude may be reached near the Atlantic Seaboard around or after 12Z Wednesday. In its wake, cool surface ridging is likely to encompass much of the interior U.S. into northern Gulf of Mexico and southern Atlantic Seaboard. However, surface cyclogenesis may commence to the immediate lee of the Canadian and northern U.S. Rockies by late Tuesday night, as a significant mid-level trough, on the leading edge of a somewhat more progressive regime emerging from the mid-latitude Pacific, approaches the British Columbia/Pacific Northwest coast. Beneath the mid-level cold core (including 500 mb temperatures below -30C) shifting across the Ohio Valley during the day, and another remnant pocket of cold air aloft across the Four Corners vicinity, diurnal convective development might become capable of producing occasional lightning. Otherwise, relatively dry and/or stable conditions appear likely to continue to prevail across much of the U.S. through this period. ..Kerr.. 10/13/2024 Read more