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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Apr 13 2024 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF OREGON AND ADJACENT NORTHEASTERN CALIFORNIA... ...SUMMARY... Thunderstorms with isolated severe hail and strong wind gusts remain possible this afternoon and early evening across parts of Oregon. ...Discussion... Current forecast reasoning, and the MRGL risk area across parts of the Oregon vicinity, appear to remain valid at this time, and thus no changes are being implemented in this forecast update. The most appreciable change has been to remove the small thunder areas from the central U.S., as any lightning should remain sparse at best, and to add a small thunder area over northern Maine where sporadic lightning is ongoing, and may continue for a couple of hours. ..Goss.. 04/13/2024 .PREV DISCUSSION... /ISSUED 1106 AM CDT Sat Apr 13 2024/ ...Far Northeast California into Oregon... An upper low off the northern/central CA coast will continue to slowly migrate east through tonight. Deep-layer south/southeasterly flow on the northeast periphery of this cyclone will advect a plume of midlevel moisture and steep lapse rates over the area. Heating through broken cloud cover will allow temperatures to warm into the 60s F by mid-afternoon and MLCAPE around 500-1000 J/kg is forecast. Moderate deep shear, with 0-6km effective shear magnitudes near 35 kt will support organized clusters, or perhaps a supercell, developing in the 20-22z time frame. Isolated large hail around 1 to 1.5 inches in diameter will be possible with the strongest cells given steep lapse rates and favorable shear in the 4-6 km layer. In addition to hail, a deeply-mixed sub-cloud layer will result in inverted-v thermodynamic profiles, and isolated strong gusts may occur. While low-level moisture will remain a limiting factor for tornado potential, a brief spin-up can not be ruled out. Enlarged low-level hodographs are evident in forecast soundings and effective SRH will increase to 100-200 m2/s2 by 22-00z amid 0-3km MLCAPE near 100 J/kg. Have added a 2 percent tornado probability to reflect this low, but non-zero potential. Uncertainty in storm coverage will preclude an upgrade to Slight risk at this time. ...Great Lakes... A low-amplitude shortwave trough migrating through large-scale northwesterly flow regime will foster elevated thunderstorm development during the evening/overnight. Weak instability (MUCAPE generally less than 500 J/kg) will limit storm intensity, though steep midlevel lapse rates and cool temperatures aloft may be sufficient for a few instances of small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Apr 13 2024 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF OREGON AND ADJACENT NORTHEASTERN CALIFORNIA... ...SUMMARY... Thunderstorms with isolated severe hail and strong wind gusts remain possible this afternoon and early evening across parts of Oregon. ...Discussion... Current forecast reasoning, and the MRGL risk area across parts of the Oregon vicinity, appear to remain valid at this time, and thus no changes are being implemented in this forecast update. The most appreciable change has been to remove the small thunder areas from the central U.S., as any lightning should remain sparse at best, and to add a small thunder area over northern Maine where sporadic lightning is ongoing, and may continue for a couple of hours. ..Goss.. 04/13/2024 .PREV DISCUSSION... /ISSUED 1106 AM CDT Sat Apr 13 2024/ ...Far Northeast California into Oregon... An upper low off the northern/central CA coast will continue to slowly migrate east through tonight. Deep-layer south/southeasterly flow on the northeast periphery of this cyclone will advect a plume of midlevel moisture and steep lapse rates over the area. Heating through broken cloud cover will allow temperatures to warm into the 60s F by mid-afternoon and MLCAPE around 500-1000 J/kg is forecast. Moderate deep shear, with 0-6km effective shear magnitudes near 35 kt will support organized clusters, or perhaps a supercell, developing in the 20-22z time frame. Isolated large hail around 1 to 1.5 inches in diameter will be possible with the strongest cells given steep lapse rates and favorable shear in the 4-6 km layer. In addition to hail, a deeply-mixed sub-cloud layer will result in inverted-v thermodynamic profiles, and isolated strong gusts may occur. While low-level moisture will remain a limiting factor for tornado potential, a brief spin-up can not be ruled out. Enlarged low-level hodographs are evident in forecast soundings and effective SRH will increase to 100-200 m2/s2 by 22-00z amid 0-3km MLCAPE near 100 J/kg. Have added a 2 percent tornado probability to reflect this low, but non-zero potential. Uncertainty in storm coverage will preclude an upgrade to Slight risk at this time. ...Great Lakes... A low-amplitude shortwave trough migrating through large-scale northwesterly flow regime will foster elevated thunderstorm development during the evening/overnight. Weak instability (MUCAPE generally less than 500 J/kg) will limit storm intensity, though steep midlevel lapse rates and cool temperatures aloft may be sufficient for a few instances of small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Apr 13 2024 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF OREGON AND ADJACENT NORTHEASTERN CALIFORNIA... ...SUMMARY... Thunderstorms with isolated severe hail and strong wind gusts remain possible this afternoon and early evening across parts of Oregon. ...Discussion... Current forecast reasoning, and the MRGL risk area across parts of the Oregon vicinity, appear to remain valid at this time, and thus no changes are being implemented in this forecast update. The most appreciable change has been to remove the small thunder areas from the central U.S., as any lightning should remain sparse at best, and to add a small thunder area over northern Maine where sporadic lightning is ongoing, and may continue for a couple of hours. ..Goss.. 04/13/2024 .PREV DISCUSSION... /ISSUED 1106 AM CDT Sat Apr 13 2024/ ...Far Northeast California into Oregon... An upper low off the northern/central CA coast will continue to slowly migrate east through tonight. Deep-layer south/southeasterly flow on the northeast periphery of this cyclone will advect a plume of midlevel moisture and steep lapse rates over the area. Heating through broken cloud cover will allow temperatures to warm into the 60s F by mid-afternoon and MLCAPE around 500-1000 J/kg is forecast. Moderate deep shear, with 0-6km effective shear magnitudes near 35 kt will support organized clusters, or perhaps a supercell, developing in the 20-22z time frame. Isolated large hail around 1 to 1.5 inches in diameter will be possible with the strongest cells given steep lapse rates and favorable shear in the 4-6 km layer. In addition to hail, a deeply-mixed sub-cloud layer will result in inverted-v thermodynamic profiles, and isolated strong gusts may occur. While low-level moisture will remain a limiting factor for tornado potential, a brief spin-up can not be ruled out. Enlarged low-level hodographs are evident in forecast soundings and effective SRH will increase to 100-200 m2/s2 by 22-00z amid 0-3km MLCAPE near 100 J/kg. Have added a 2 percent tornado probability to reflect this low, but non-zero potential. Uncertainty in storm coverage will preclude an upgrade to Slight risk at this time. ...Great Lakes... A low-amplitude shortwave trough migrating through large-scale northwesterly flow regime will foster elevated thunderstorm development during the evening/overnight. Weak instability (MUCAPE generally less than 500 J/kg) will limit storm intensity, though steep midlevel lapse rates and cool temperatures aloft may be sufficient for a few instances of small hail. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 0131 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z No changes to the ongoing forecast. ..Wendt.. 04/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Apr 13 2024/ ...Synopsis... Fire weather conditions are expected again on Sunday across a broad swath of the Four Corners region with more concentrated areas of elevated conditions across the southern High Plains. The upper low currently off the central CA coast is forecast to move onshore over the next 48 hours, reaching the lower CO River Valley region by late Sunday. This will result in surface pressure falls across much of the intermountain West with an accompanying uptick in low-level winds. Widespread fire weather conditions are anticipated across much of the Four Corners region, but fuel analyses suggest that most fuels are currently not receptive. A weaker low-level mass response is anticipated further east across the southern High Plains, but corridors of dry/windy conditions are anticipated over areas with receptive fuels. ...Southeast NM to the southern Permian Basin... Both deterministic and ensemble guidance show the potential for pockets of elevated fire weather conditions across NM into adjacent areas of western TX and southern CO. However, the most consistent signal among all solutions appears to be across southeast NM into the southern Permian Basin where 15-20 mph winds and RH in the single digits to low teens are expected. This signal is likely attributable to topographical influences with enhanced downslope warming/drying in the lee of the Guadelupe Mountains within a modest west/southwesterly flow regime. Dry grasses across this region should support the fire weather concern, and fuel guidance will be monitored across the Four Corners region given the relatively higher confidence for elevated (to locally critical) fire weather conditions. ...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 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Sat Apr 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER PARTS OF PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are possible from late afternoon into the evening on Sunday, from southwestern Ohio east-northeastward to southwestern New England. Damaging winds should be the primary hazard, but a tornado or two and large hail are also possible. ...Synopsis... A mid-level closed low initially centered over California will move eastward across the Great Basin Sunday, with downstream ridging to remain over the Plains/central U.S. through the period. Farther east, west-northwesterly flow aloft will prevail, with a belt of enhanced/70 to 80 kt speeds across the Great Lakes and Northeast states. A subtle short-wave trough/vort max associated with the mid-level jet is forecast to shift across the Upper Ohio Valley/central Appalachians through the late afternoon/evening hours. At the surface, a weak frontal low initially over the Lower Michigan vicinity should move quickly eastward to western New England by the evening. Meanwhile a trailing, east-west cold front will advance southward across the southern Great Lakes region and into the central Appalachians and Midwest States through the afternoon and evening, and reaching the Mid-Atlantic region and Ohio Valley overnight. In the West, a cold front associated with the advancing upper low will cross the Great Basin and Desert Southwest with time, reaching the High Plains by Monday morning. ...Upper Ohio Valley area to far southwestern New England... Steep mid-level lapse rates aloft are forecast to overspread the northeastern quarter of the country Sunday, as a cold front drops southward across the Northeast states. Beneath this eastward-advecting mid-level lapse rate plume, modest east-northeastward advection of low-level moisture will occur, with 50s dewpoints expected ahead of the front, from southwestern New England westward, by late afternoon in a narrow east-to-west corridor. This -- combined with diurnal heating across the warm sector, should yield mixed-layer CAPE values to reach 500 J/kg over southern New York/eastern Pennsylvania, to 1500 J/kg into western Pennsylvania and Ohio. As the front sags southward and destabilization maximizes through the afternoon, storm initiation along and just ahead of the front is expected. Storms may initially include cellular mode, especially from central Pennsylvania westward, but flow roughly parallel to the front should favor quick upscale/linear evolution. Still, weak veering and rapid strengthening of the flow with height will support organized storms -- including rotating updrafts within the line, and particularly with any storms which can remain at least transiently cellular. While the expected linear storm mode should help to limit tornado potential, a couple of tornadoes are anticipated, particularly across western and central Pennsylvania, where large hail may also occur. Otherwise, the primary severe risk across the region should be damaging wind gusts, aided by 40 to 50 kt westerlies extending as low as 900mb per model point-forecast soundings. Storms will spread southward into the evening, but should eventually weaken diurnally as the boundary layer begins to stabilize. ..Goss.. 04/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1106 AM CDT Sat Apr 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM FAR NORTHEAST CALIFORNIA INTO CENTRAL OREGON... ...SUMMARY... Thunderstorms with isolated severe hail and strong wind gusts will be possible this afternoon and early evening across parts of Oregon. ...Far Northeast California into Oregon... An upper low off the northern/central CA coast will continue to slowly migrate east through tonight. Deep-layer south/southeasterly flow on the northeast periphery of this cyclone will advect a plume of midlevel moisture and steep lapse rates over the area. Heating through broken cloud cover will allow temperatures to warm into the 60s F by mid-afternoon and MLCAPE around 500-1000 J/kg is forecast. Moderate deep shear, with 0-6km effective shear magnitudes near 35 kt will support organized clusters, or perhaps a supercell, developing in the 20-22z time frame. Isolated large hail around 1 to 1.5 inches in diameter will be possible with the strongest cells given steep lapse rates and favorable shear in the 4-6 km layer. In addition to hail, a deeply-mixed sub-cloud layer will result in inverted-v thermodynamic profiles, and isolated strong gusts may occur. While low-level moisture will remain a limiting factor for tornado potential, a brief spin-up can not be ruled out. Enlarged low-level hodographs are evident in forecast soundings and effective SRH will increase to 100-200 m2/s2 by 22-00z amid 0-3km MLCAPE near 100 J/kg. Have added a 2 percent tornado probability to reflect this low, but non-zero potential. Uncertainty in storm coverage will preclude an upgrade to Slight risk at this time. ...Great Lakes... A low-amplitude shortwave trough migrating through large-scale northwesterly flow regime will foster elevated thunderstorm development during the evening/overnight. Weak instability (MUCAPE generally less than 500 J/kg) will limit storm intensity, though steep midlevel lapse rates and cool temperatures aloft may be sufficient for a few instances of small hail. ..Leitman/Bentley.. 04/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1106 AM CDT Sat Apr 13 2024 Valid 131630Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM FAR NORTHEAST CALIFORNIA INTO CENTRAL OREGON... ...SUMMARY... Thunderstorms with isolated severe hail and strong wind gusts will be possible this afternoon and early evening across parts of Oregon. ...Far Northeast California into Oregon... An upper low off the northern/central CA coast will continue to slowly migrate east through tonight. Deep-layer south/southeasterly flow on the northeast periphery of this cyclone will advect a plume of midlevel moisture and steep lapse rates over the area. Heating through broken cloud cover will allow temperatures to warm into the 60s F by mid-afternoon and MLCAPE around 500-1000 J/kg is forecast. Moderate deep shear, with 0-6km effective shear magnitudes near 35 kt will support organized clusters, or perhaps a supercell, developing in the 20-22z time frame. Isolated large hail around 1 to 1.5 inches in diameter will be possible with the strongest cells given steep lapse rates and favorable shear in the 4-6 km layer. In addition to hail, a deeply-mixed sub-cloud layer will result in inverted-v thermodynamic profiles, and isolated strong gusts may occur. While low-level moisture will remain a limiting factor for tornado potential, a brief spin-up can not be ruled out. Enlarged low-level hodographs are evident in forecast soundings and effective SRH will increase to 100-200 m2/s2 by 22-00z amid 0-3km MLCAPE near 100 J/kg. Have added a 2 percent tornado probability to reflect this low, but non-zero potential. Uncertainty in storm coverage will preclude an upgrade to Slight risk at this time. ...Great Lakes... A low-amplitude shortwave trough migrating through large-scale northwesterly flow regime will foster elevated thunderstorm development during the evening/overnight. Weak instability (MUCAPE generally less than 500 J/kg) will limit storm intensity, though steep midlevel lapse rates and cool temperatures aloft may be sufficient for a few instances of small hail. ..Leitman/Bentley.. 04/13/2024 Read more