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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0233 PM CDT Mon Sep 01 2025 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SOUTHERN KANSAS TO NORTHWEST OKLAHOMA... ...SUMMARY... Isolated severe thunderstorms may occur across parts of southern Kansas and western/northern Oklahoma this afternoon and evening, with isolated large hail and damaging winds the main threats. ...20z Update... The previous forecast remains on track with only minor adjustments made to reflect recent convective trends. Initial thunderstorm development along a weak surface front is noted from northeast to southwest KS as of 19 UTC. Based on regional VWPs, mid-level flow remains relatively strongest across southern to southwest KS on the west/southwest side of the upper wave, which should promote a slightly higher potential for severe gusts and/or hail this afternoon/evening. The Marginal risk area was slightly adjusted to better capture this potential. See MCD #2025 for additional short-term details. Elsewhere, only minor adjustments to the thunder line were needed. An occasional lightning flash or two will be possible during the 09-12 UTC period across central CA, but recent guidance continues to suggest that lightning coverage/probability will likely remain below 10%. ..Moore.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Mon Sep 01 2025/ ...Southern/Central Plains... A mid-level shortwave trough centered over eastern NE late this morning will move southeastward toward the southern Plains and Ozarks by tonight. This will occur in association with a belt of modestly enhanced north-northwesterly mid-level winds (around 30-40 kt at 500 mb). While the related surface response will remain muted, a weak surface front/wind shift will progress southward from KS into OK, with a relatively moist air mass preceding the advancing boundary. Ongoing low clouds/stratus should continue to gradually erode this afternoon, yielding ample insolation and a corridor of moderate instability and steepening low-level lapse rates, particularly across southern KS into northwest OK. Widely scattered thunderstorm development is probable by mid/late afternoon near the front/wind shift as the boundary layer warms. The enhanced north-northwesterly flow aloft will contribute to 30-40 kt of effective bulk shear, which should support multicell clusters and perhaps marginal supercells. Isolated severe hail/damaging winds will be possible through early evening as storms develop southward from parts of southern KS into western/northern OK. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0233 PM CDT Mon Sep 01 2025 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SOUTHERN KANSAS TO NORTHWEST OKLAHOMA... ...SUMMARY... Isolated severe thunderstorms may occur across parts of southern Kansas and western/northern Oklahoma this afternoon and evening, with isolated large hail and damaging winds the main threats. ...20z Update... The previous forecast remains on track with only minor adjustments made to reflect recent convective trends. Initial thunderstorm development along a weak surface front is noted from northeast to southwest KS as of 19 UTC. Based on regional VWPs, mid-level flow remains relatively strongest across southern to southwest KS on the west/southwest side of the upper wave, which should promote a slightly higher potential for severe gusts and/or hail this afternoon/evening. The Marginal risk area was slightly adjusted to better capture this potential. See MCD #2025 for additional short-term details. Elsewhere, only minor adjustments to the thunder line were needed. An occasional lightning flash or two will be possible during the 09-12 UTC period across central CA, but recent guidance continues to suggest that lightning coverage/probability will likely remain below 10%. ..Moore.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Mon Sep 01 2025/ ...Southern/Central Plains... A mid-level shortwave trough centered over eastern NE late this morning will move southeastward toward the southern Plains and Ozarks by tonight. This will occur in association with a belt of modestly enhanced north-northwesterly mid-level winds (around 30-40 kt at 500 mb). While the related surface response will remain muted, a weak surface front/wind shift will progress southward from KS into OK, with a relatively moist air mass preceding the advancing boundary. Ongoing low clouds/stratus should continue to gradually erode this afternoon, yielding ample insolation and a corridor of moderate instability and steepening low-level lapse rates, particularly across southern KS into northwest OK. Widely scattered thunderstorm development is probable by mid/late afternoon near the front/wind shift as the boundary layer warms. The enhanced north-northwesterly flow aloft will contribute to 30-40 kt of effective bulk shear, which should support multicell clusters and perhaps marginal supercells. Isolated severe hail/damaging winds will be possible through early evening as storms develop southward from parts of southern KS into western/northern OK. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTH CENTRAL AND EASTERN KANSAS INTO WESTERN AND CENTRAL MISSOURI AND PORTIONS OF NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong thunderstorms may impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon into early evening, accompanied by at least some risk for severe hail and wind. ...Discussion... Tuesday into Wednesday, models indicate little change to the amplified large-scale pattern across the mid-latitude eastern Pacific through North America. Mid/upper troughing will be maintained to the east of the Canadian/U.S. Rockies, reinforced by one vigorous short wave trough forecast to continue digging southeast of the northern Great Plains/Upper Midwest vicinity, as a similar upstream perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. A surface cold front associated with the lead impulse is forecast to continue surging southeastward through the remainder of the Midwest/lower Ohio and middle Mississippi Valleys and central Great Plains, accompanied by notable further low-level drying. Seasonably high moisture content will generally remain confined to a plume across the central Gulf Basin and Florida Peninsula into southwestern Atlantic, on the southern through southeastern periphery of the larger-scale mid/upper troughing. ...Central Great Plains into Missouri Ozarks... Mid/upper forcing for ascent overspreading the region, to the southwest of the primary digging mid-level troughing/evolving low, remains unclear due to lingering model spread. However, models suggest that boundary-layer moisture will remain sufficient to support moderate potential instability beneath a pre-frontal plume of steepening lower/mid-tropospheric lapse rates. Focusing on the southward advancing cold front, and pre-frontal surface troughing, at least isolated to widely scattered thunderstorm development appears possible by late Wednesday afternoon. Beneath strengthening northwesterly mid-level flow, the environment may become conducive to supercells and one or two small organizing clusters with potential to produce severe hail and wind, before convection weakens during the evening with the loss of daytime heating. ..Kerr.. 09/01/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...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 0203 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z Tomorrow's fire weather forecast remains largely on-track, with only minor adjustments needed to the isolated dry thunderstorm area based on the latest high-resolution ensemble guidance. Gusty/erratic thunderstorm outflow winds are possible across the dry thunderstorm area given steep low-level lapse rates. Hot, dry, and unstable conditions are also forecast to develop across portions of California into Oregon tomorrow afternoon/evening, which may promote increasing fire activity from recent holdovers, longer burn periods on any ongoing large fires, and an increasing risk for large plume-dominated fires. Please see the previous discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 09/01/2025 .PREV DISCUSSION... /ISSUED 1216 AM CDT Mon Sep 01 2025/ ...Synopsis... The primary fire weather concern for Tuesday will be the potential for isolated dry thunderstorms across portions of northern CA into portions of northwest NV and central OR. Recent water-vapor imagery depicts a weak upper low off the southern CA coast that is forecast to meander northward over the next 48 hours. As this occurs, lift and mid-level moistening ahead of the wave will promote sufficient destabilization for convection beginning as early as 12z Tuesday morning across central CA, spreading northward through the afternoon and evening. In general, mid-level moisture quality should decrease with northward extent on the fringes of the better monsoonal moisture. An ensemble of forecast soundings suggests PWAT values may range from 0.6 to 0.8 inches across northern CA/northwest NV/central OR, which should favor a mix of wet and dry thunderstorms. Forecast storm motions between 15-20 knots may also help promote isolated dry lightning strikes over a landscape with ERCs between the 80th to 95th percentiles. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

049
ABPZ20 KNHC 011736
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon Sep 1 2025

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

Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Storm Kiko, located in the east Pacific basin well west-southwest
of the southern tip of the Baja California peninsula. Kiko is
expected to cross into the central Pacific basin by the weekend.

South of Southwestern Mexico (EP94):
Showers and thunderstorms associated with a tropical wave located
less than 150 miles off the coast of southwestern Mexico are
starting to become better organized, and recent satellite-derived
wind data indicate that winds to 35 mph are present in the
disturbance close to the coast of Mexico. This system is expected
to become a tropical depression by the middle of the week. This
system is expected to move west-northwestward to northwestward at
10 to 15 mph off the coast of southwestern Mexico during the next
couple of days, then could turn northward and approach the Baja
California peninsula later this week. Interests in the Baja
California peninsula should monitor the progress of the
disturbance, as watches or warnings could be required for portions
of this area on Tuesday. Regardless of development, heavy rainfall
is possible across coastal portions of southwestern and
west-central Mexico today through mid-week. Heavy rainfall is also
expected across Baja California Sur and northwestern Mexico Tuesday
night through late this week. This heavy rainfall could lead to
flash flooding, especially in mountainous areas.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Hagen

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTHEASTERN NORTH DAKOTA...EASTERN SOUTH DAKOTA...SOUTHWESTERN INTO CENTRAL MINNESOTA... ...SUMMARY... Widely scattered to scattered strong thunderstorm development is possible across parts of the eastern Dakotas into Minnesota, as well as portions of the Southwest into Great Basin, late Tuesday afternoon and evening. The risk for severe weather still appears generally low, but a couple of storms could produce marginally severe hail and localized strong surface gusts. ...Discussion... In the mean, models indicate that mid/upper heights will remain relatively high across much of the eastern Pacific into western North America. However, an embedded blocking high across the northeastern Pacific is forecast to become at least a bit less prominent, and lower heights to its southeast and south may consolidate. This latter regime includes a notable low, which may undergo deepening while retrograding offshore of the Pacific Northwest coast Tuesday through Tuesday night. At the same time, a couple of weaker perturbations appear likely to slowly shift north-northeastward, inland of California and northern Baja California coastal areas. Downstream of this regime, large-scale mid/upper troughing will be maintained to the east of the Rockies, as far south as the Gulf Basin, and reinforced by a vigorous short wave trough emerging from the high latitudes. By Tuesday evening, this perturbation is forecast to begin digging across the international border into the northern Great Plains/Upper Midwest, accompanied by another cold front. Seasonably high moisture content, on the southern periphery of the larger-scale cyclonic regime, has already become largely confined to the subtropical latitudes, with further southward suppression forecast across southern Texas and the Florida Peninsula through this period. However, a tongue of more modest moisture lingers inland across much of the Gulf Coast states and eastern Great Plains, along the southwestern through western flank of the troughing. Weak to modest destabilization, with insolation, and forcing for ascent associated with short wave perturbations embedded within the evolving pattern are likely to support a number of areas of scattered thunderstorm activity Tuesday through Tuesday night. However, the risk for severe weather appears generally low across most areas. ...Northern Great Plains... The mid-level cold core of the approaching vigorous short wave trough will remain post-frontal, but models suggest that a plume of modestly steep lower/mid-tropospheric lapse rates ahead of the front may contribute to destabilization sufficient for vigorous thunderstorm development by late Tuesday afternoon. It appears that this may become focused across parts of the eastern Dakotas into western Minnesota, where a residual pocket of boundary-layer dew points as high as the lower/mid 60s may contribute to CAPE on the order of 1000-2000+ J/kg. Forecast soundings suggest that deep-layer shear will remain generally weak, but mid/upper forcing for ascent might contribute to scattered upscale growing clusters with potential to produce marginally severe hail and wind. ...Southwestern Deserts into Great Basin... Areas of thunderstorm development will likely be rooted above a warm and deeply mixed boundary layer, with thermodynamic profiles conducive to at least isolated to widely scattered microbursts. However, the extent to which convection may be able to grow upscale into consolidating clusters, with outflow enhanced by downward transfer of momentum associated with southeasterly to southerly mid-level flow, remains unclear. Forecast ambient flow appears generally on the order 15-25 kts, but perhaps with embedded stronger speed maxima. It is possible that severe wind probabilities at or above 5 percent may still be needed, if/when potential corridors become more confidently evident. ..Kerr.. 09/01/2025 Read more