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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Oct 18 2024 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS AND FROM NORTHERN ARIZONA INTO SOUTHWEST COLORADO... ...SUMMARY... Isolated severe hail, damaging gusts and a tornado or two will be possible this afternoon and evening over parts of the southern Rockies and southern High Plains. An isolated threat for severe may locally develop from northern Arizona into southwest Colorado. ...Synopsis... Water-vapor imagery shows a mid- to upper-level low centered over the NV/UT/AZ border vicinity and this feature will move east-southeast into northern AZ before nearly stalling later tonight. An associated cold front will push east across the Four Corners through this afternoon. Farther east, the southwestern extension of a Midwest front will push southward through eastern CO before decelerating near the Raton Mesa. ...Northern AZ into southwest CO through this afternoon... Strong large-scale ascent immediately ahead of the upper low will gradually shift east across the Mogollon Rim through the early afternoon. The 12 UTC Flagstaff, AZ raob showed weak buoyancy but an enlarged hodograph. Visible-satellite and radar imagery show widely scattered deepening convection near the Rim on the northern extent of a moist axis from the lower deserts into northern AZ. Forecast soundings show surface-based buoyancy (100-400 J/kg SBCAPE) across northern/eastern AZ. As a result, a couple of shallow transient-rotating storms may yield short-duration risk for a brief tornado and/or locally strong gust. The risk for strong/severe gusts may extend as far northeast as southwest CO with a stronger storm or two before cold front passage later today. ...Southern High Plains and escarpments... Late morning surface analysis and visible-satellite imagery denote a low-level moisture plume from west TX into eastern NM, where dewpoints range in the 50s deg F. Heating through the mid-late afternoon will yield generally 500-1000 J/kg MLCAPE across eastern NM. Model guidance indicates a weakened capping inversion towards the late afternoon over the Eastern Plains of NM. Initially isolated to widely scattered storm coverage during the 21z-00z window will transition to greater storm coverage towards sunset and into the overnight, especially over the northeast quarter of NM. Despite the time-lagged nature of the forcing associated with the upper low, storms will mature into the evening. The stronger storms will potentially be capable of an isolated risk for hail/wind. Where surface-based buoyancy lingers near the escarpment in the northeast quarter of NM during the early evening, a threat for a tornado may develop. ..Smith/Squitieri.. 10/18/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Oct 18 2024 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS AND FROM NORTHERN ARIZONA INTO SOUTHWEST COLORADO... ...SUMMARY... Isolated severe hail, damaging gusts and a tornado or two will be possible this afternoon and evening over parts of the southern Rockies and southern High Plains. An isolated threat for severe may locally develop from northern Arizona into southwest Colorado. ...Synopsis... Water-vapor imagery shows a mid- to upper-level low centered over the NV/UT/AZ border vicinity and this feature will move east-southeast into northern AZ before nearly stalling later tonight. An associated cold front will push east across the Four Corners through this afternoon. Farther east, the southwestern extension of a Midwest front will push southward through eastern CO before decelerating near the Raton Mesa. ...Northern AZ into southwest CO through this afternoon... Strong large-scale ascent immediately ahead of the upper low will gradually shift east across the Mogollon Rim through the early afternoon. The 12 UTC Flagstaff, AZ raob showed weak buoyancy but an enlarged hodograph. Visible-satellite and radar imagery show widely scattered deepening convection near the Rim on the northern extent of a moist axis from the lower deserts into northern AZ. Forecast soundings show surface-based buoyancy (100-400 J/kg SBCAPE) across northern/eastern AZ. As a result, a couple of shallow transient-rotating storms may yield short-duration risk for a brief tornado and/or locally strong gust. The risk for strong/severe gusts may extend as far northeast as southwest CO with a stronger storm or two before cold front passage later today. ...Southern High Plains and escarpments... Late morning surface analysis and visible-satellite imagery denote a low-level moisture plume from west TX into eastern NM, where dewpoints range in the 50s deg F. Heating through the mid-late afternoon will yield generally 500-1000 J/kg MLCAPE across eastern NM. Model guidance indicates a weakened capping inversion towards the late afternoon over the Eastern Plains of NM. Initially isolated to widely scattered storm coverage during the 21z-00z window will transition to greater storm coverage towards sunset and into the overnight, especially over the northeast quarter of NM. Despite the time-lagged nature of the forcing associated with the upper low, storms will mature into the evening. The stronger storms will potentially be capable of an isolated risk for hail/wind. Where surface-based buoyancy lingers near the escarpment in the northeast quarter of NM during the early evening, a threat for a tornado may develop. ..Smith/Squitieri.. 10/18/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Oct 18 2024 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SOUTHERN CALIFORNIA COAST... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 10/18/2024 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Oct 18 2024/ ...Synopsis... Critical fire weather conditions are possible this afternoon into the overnight hours along portions of the southern California coast. Elevated fire weather conditions are possible along the western slopes of the Sacramento Valley in northern California. Early-morning surface observations show a cold front pushing southeast across the Great Basin and central/southern CA. Strong northerly low to mid-level winds are anticipated behind this front by mid-morning across the southern CA ranges, which should induce an offshore flow regime. An influx of drier air combined with downslope warming/drying will promote areas of RH reductions to 10-20% in the lee of the coastal ranges. Latest guidance suggests elevated to critical fire weather conditions are most probable in the lee of the San Gabriel and San Bernardino ranges with winds gusting up to 40-50 mph possible. These conditions are expected to linger into the overnight hours as a surface high builds to the north across the Great Basin and reinforces the offshore pressure-gradient flow. Elevated to critical fire weather conditions are anticipated further east across the Mojave Desert into the Sonoran Desert in southwest AZ, but limited fuel availability and/or receptiveness should limit fire concerns. Further north through the Sacramento Valley, dewpoints have fallen by around 20 F over the past 12-18 hours in the wake of the surface front. This drier air, combined with diurnal heating/mixing, will promote 15-25% RH minimums this afternoon as breezy post-frontal winds between 15-25 mph persist through the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

The New Jersey Department of Environmental Protection issued a drought watch on Oct. 17, urging the public to conserve water as rainfall has been below normal for the past 90 days. Asbury Park Press (N.J.), Oct 17, 2024

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Fri Oct 18 2024 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail, damaging gusts and a tornado or two will be possible this afternoon and evening over parts of the southern Rockies and southern High Plains. ...Synopsis... In mid/upper levels, a heretofore progressive and high-amplitude pattern will slow down temporarily, across the western half of the CONUS. A strong trough is apparent in moisture-channel imagery from the northern Rockies south-southwestward across the Great Basin to near the lower Colorado River Valley. A 500-mb low is forming along the trough in NV -- and will deepen through the period while anchoring an increasingly pronounced and slower-moving cyclone. By 00Z, the low should be over central AZ between FLG-PHX, then wobble erratically over the same area through the remainder of the period. At 11Z, the surface analysis showed a cold front from northwestern MN, through a low between PIR-HON, then southwestward to another low near AKO and into central CO. This front should shift slowly southeastward through the period, to a position from northeastern MN to northeastern NE to near RTN by 12Z. There it should connect to another cold front now analyzed from a surface low over southeastern UT, southwestward across northern/southwestern AZ. The western front should move east-southeastward into central NM tonight, then decelerate in step with the associated mid/upper cyclone. A vast, continental anticyclone surrounds a high analyzed over western PA, and covers most of the CONUS from the Mississippi Valley eastward, with ridging southwestward across south TX. The high should remain over the interior Mid-Atlantic region through the period, while ridging persists southwestward through south TX. ...Southern Rockies/High Plains region... A band of convection -- now producing considerable lighting from southeastern UT into northern AZ -- should persist through much of the period and shift eastward-southeastward, reaching from the San Juan Mountains of southwestern CO across much of western NM between 00Z-03Z this evening. While isolated strong gusts or small hail may occur with this partly frontally forced activity, very limited buoyancy should preclude an organized severe threat. Farther east, isolated to widely scattered thunderstorms should form in the warm sector this afternoon, over and near the ranges from the Guadalupe Mountains northward to the east side of the Sangre de Cristos. Convection also may develop over adjoining Plains, given diurnal heating in a weakly capped setting that lacks an antecedent EML. Some of this activity may become supercellular amidst increasing deep shear, with isolated damaging gusts and severe hail possible. Tornado potential still appears marginal. A host of mostly offsetting factors continue in the forecast environment in and near the outlook area today, keeping the unconditional severe probabilities in the marginal range for this cycle. Thermodynamically, the immobility and intensity of the low-level anticyclone over the East will limit favorable moisture to a narrow, only partially Gulf-modified return-flow corridor through the period. 50s F surface dewpoints -- already common at lower elevations in eastern NM, should mix into the 40s F where diurnal heating is most sustained today over the Plains. Upper 40s to lower 50s dewpoints may persist farther northwest under more persistently cloudy areas, leading to greater RH and lower LCL, but amid cooler surface temperatures. However, at higher elevations, this still may support surface-based effective-inflow parcels. With the coolest midlevel temperatures and strongest DCVA aloft lagging closer to the cyclone core, and mostly behind the low-level cold front, poor midlevel lapse rates will limit buoyancy over the region. This, and lack of richer moisture, should keep MLCAPE generally in the 300-800 J/kg range -- and highly variable depending on elevation and patchy heating/mixing. Vertical shear amid southwest flow aloft will strengthen through the evening along/ahead of the western frontal zone as the cyclone digs into AZ. Enlarging hodographs and low-level shear will accompany a strengthening low-level jet and greater moisture this evening and tonight over much of eastern NM, along/ahead of the slow-moving frontal convective arc. However, this also will coincide with nocturnal boundary-layer stabilization and likely an increasingly messy convective mode. A window of tornado potential may exist from late afternoon into early evening during that transition, especially at higher elevations of the Plains/mesa country, but still appears too isolated and conditional for more than marginal probabilities. ..Edwards/Goss.. 10/18/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Fri Oct 18 2024 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail, damaging gusts and a tornado or two will be possible this afternoon and evening over parts of the southern Rockies and southern High Plains. ...Synopsis... In mid/upper levels, a heretofore progressive and high-amplitude pattern will slow down temporarily, across the western half of the CONUS. A strong trough is apparent in moisture-channel imagery from the northern Rockies south-southwestward across the Great Basin to near the lower Colorado River Valley. A 500-mb low is forming along the trough in NV -- and will deepen through the period while anchoring an increasingly pronounced and slower-moving cyclone. By 00Z, the low should be over central AZ between FLG-PHX, then wobble erratically over the same area through the remainder of the period. At 11Z, the surface analysis showed a cold front from northwestern MN, through a low between PIR-HON, then southwestward to another low near AKO and into central CO. This front should shift slowly southeastward through the period, to a position from northeastern MN to northeastern NE to near RTN by 12Z. There it should connect to another cold front now analyzed from a surface low over southeastern UT, southwestward across northern/southwestern AZ. The western front should move east-southeastward into central NM tonight, then decelerate in step with the associated mid/upper cyclone. A vast, continental anticyclone surrounds a high analyzed over western PA, and covers most of the CONUS from the Mississippi Valley eastward, with ridging southwestward across south TX. The high should remain over the interior Mid-Atlantic region through the period, while ridging persists southwestward through south TX. ...Southern Rockies/High Plains region... A band of convection -- now producing considerable lighting from southeastern UT into northern AZ -- should persist through much of the period and shift eastward-southeastward, reaching from the San Juan Mountains of southwestern CO across much of western NM between 00Z-03Z this evening. While isolated strong gusts or small hail may occur with this partly frontally forced activity, very limited buoyancy should preclude an organized severe threat. Farther east, isolated to widely scattered thunderstorms should form in the warm sector this afternoon, over and near the ranges from the Guadalupe Mountains northward to the east side of the Sangre de Cristos. Convection also may develop over adjoining Plains, given diurnal heating in a weakly capped setting that lacks an antecedent EML. Some of this activity may become supercellular amidst increasing deep shear, with isolated damaging gusts and severe hail possible. Tornado potential still appears marginal. A host of mostly offsetting factors continue in the forecast environment in and near the outlook area today, keeping the unconditional severe probabilities in the marginal range for this cycle. Thermodynamically, the immobility and intensity of the low-level anticyclone over the East will limit favorable moisture to a narrow, only partially Gulf-modified return-flow corridor through the period. 50s F surface dewpoints -- already common at lower elevations in eastern NM, should mix into the 40s F where diurnal heating is most sustained today over the Plains. Upper 40s to lower 50s dewpoints may persist farther northwest under more persistently cloudy areas, leading to greater RH and lower LCL, but amid cooler surface temperatures. However, at higher elevations, this still may support surface-based effective-inflow parcels. With the coolest midlevel temperatures and strongest DCVA aloft lagging closer to the cyclone core, and mostly behind the low-level cold front, poor midlevel lapse rates will limit buoyancy over the region. This, and lack of richer moisture, should keep MLCAPE generally in the 300-800 J/kg range -- and highly variable depending on elevation and patchy heating/mixing. Vertical shear amid southwest flow aloft will strengthen through the evening along/ahead of the western frontal zone as the cyclone digs into AZ. Enlarging hodographs and low-level shear will accompany a strengthening low-level jet and greater moisture this evening and tonight over much of eastern NM, along/ahead of the slow-moving frontal convective arc. However, this also will coincide with nocturnal boundary-layer stabilization and likely an increasingly messy convective mode. A window of tornado potential may exist from late afternoon into early evening during that transition, especially at higher elevations of the Plains/mesa country, but still appears too isolated and conditional for more than marginal probabilities. ..Edwards/Goss.. 10/18/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Fri Oct 18 2024 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail, damaging gusts and a tornado or two will be possible this afternoon and evening over parts of the southern Rockies and southern High Plains. ...Synopsis... In mid/upper levels, a heretofore progressive and high-amplitude pattern will slow down temporarily, across the western half of the CONUS. A strong trough is apparent in moisture-channel imagery from the northern Rockies south-southwestward across the Great Basin to near the lower Colorado River Valley. A 500-mb low is forming along the trough in NV -- and will deepen through the period while anchoring an increasingly pronounced and slower-moving cyclone. By 00Z, the low should be over central AZ between FLG-PHX, then wobble erratically over the same area through the remainder of the period. At 11Z, the surface analysis showed a cold front from northwestern MN, through a low between PIR-HON, then southwestward to another low near AKO and into central CO. This front should shift slowly southeastward through the period, to a position from northeastern MN to northeastern NE to near RTN by 12Z. There it should connect to another cold front now analyzed from a surface low over southeastern UT, southwestward across northern/southwestern AZ. The western front should move east-southeastward into central NM tonight, then decelerate in step with the associated mid/upper cyclone. A vast, continental anticyclone surrounds a high analyzed over western PA, and covers most of the CONUS from the Mississippi Valley eastward, with ridging southwestward across south TX. The high should remain over the interior Mid-Atlantic region through the period, while ridging persists southwestward through south TX. ...Southern Rockies/High Plains region... A band of convection -- now producing considerable lighting from southeastern UT into northern AZ -- should persist through much of the period and shift eastward-southeastward, reaching from the San Juan Mountains of southwestern CO across much of western NM between 00Z-03Z this evening. While isolated strong gusts or small hail may occur with this partly frontally forced activity, very limited buoyancy should preclude an organized severe threat. Farther east, isolated to widely scattered thunderstorms should form in the warm sector this afternoon, over and near the ranges from the Guadalupe Mountains northward to the east side of the Sangre de Cristos. Convection also may develop over adjoining Plains, given diurnal heating in a weakly capped setting that lacks an antecedent EML. Some of this activity may become supercellular amidst increasing deep shear, with isolated damaging gusts and severe hail possible. Tornado potential still appears marginal. A host of mostly offsetting factors continue in the forecast environment in and near the outlook area today, keeping the unconditional severe probabilities in the marginal range for this cycle. Thermodynamically, the immobility and intensity of the low-level anticyclone over the East will limit favorable moisture to a narrow, only partially Gulf-modified return-flow corridor through the period. 50s F surface dewpoints -- already common at lower elevations in eastern NM, should mix into the 40s F where diurnal heating is most sustained today over the Plains. Upper 40s to lower 50s dewpoints may persist farther northwest under more persistently cloudy areas, leading to greater RH and lower LCL, but amid cooler surface temperatures. However, at higher elevations, this still may support surface-based effective-inflow parcels. With the coolest midlevel temperatures and strongest DCVA aloft lagging closer to the cyclone core, and mostly behind the low-level cold front, poor midlevel lapse rates will limit buoyancy over the region. This, and lack of richer moisture, should keep MLCAPE generally in the 300-800 J/kg range -- and highly variable depending on elevation and patchy heating/mixing. Vertical shear amid southwest flow aloft will strengthen through the evening along/ahead of the western frontal zone as the cyclone digs into AZ. Enlarging hodographs and low-level shear will accompany a strengthening low-level jet and greater moisture this evening and tonight over much of eastern NM, along/ahead of the slow-moving frontal convective arc. However, this also will coincide with nocturnal boundary-layer stabilization and likely an increasingly messy convective mode. A window of tornado potential may exist from late afternoon into early evening during that transition, especially at higher elevations of the Plains/mesa country, but still appears too isolated and conditional for more than marginal probabilities. ..Edwards/Goss.. 10/18/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Fri Oct 18 2024 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail, damaging gusts and a tornado or two will be possible this afternoon and evening over parts of the southern Rockies and southern High Plains. ...Synopsis... In mid/upper levels, a heretofore progressive and high-amplitude pattern will slow down temporarily, across the western half of the CONUS. A strong trough is apparent in moisture-channel imagery from the northern Rockies south-southwestward across the Great Basin to near the lower Colorado River Valley. A 500-mb low is forming along the trough in NV -- and will deepen through the period while anchoring an increasingly pronounced and slower-moving cyclone. By 00Z, the low should be over central AZ between FLG-PHX, then wobble erratically over the same area through the remainder of the period. At 11Z, the surface analysis showed a cold front from northwestern MN, through a low between PIR-HON, then southwestward to another low near AKO and into central CO. This front should shift slowly southeastward through the period, to a position from northeastern MN to northeastern NE to near RTN by 12Z. There it should connect to another cold front now analyzed from a surface low over southeastern UT, southwestward across northern/southwestern AZ. The western front should move east-southeastward into central NM tonight, then decelerate in step with the associated mid/upper cyclone. A vast, continental anticyclone surrounds a high analyzed over western PA, and covers most of the CONUS from the Mississippi Valley eastward, with ridging southwestward across south TX. The high should remain over the interior Mid-Atlantic region through the period, while ridging persists southwestward through south TX. ...Southern Rockies/High Plains region... A band of convection -- now producing considerable lighting from southeastern UT into northern AZ -- should persist through much of the period and shift eastward-southeastward, reaching from the San Juan Mountains of southwestern CO across much of western NM between 00Z-03Z this evening. While isolated strong gusts or small hail may occur with this partly frontally forced activity, very limited buoyancy should preclude an organized severe threat. Farther east, isolated to widely scattered thunderstorms should form in the warm sector this afternoon, over and near the ranges from the Guadalupe Mountains northward to the east side of the Sangre de Cristos. Convection also may develop over adjoining Plains, given diurnal heating in a weakly capped setting that lacks an antecedent EML. Some of this activity may become supercellular amidst increasing deep shear, with isolated damaging gusts and severe hail possible. Tornado potential still appears marginal. A host of mostly offsetting factors continue in the forecast environment in and near the outlook area today, keeping the unconditional severe probabilities in the marginal range for this cycle. Thermodynamically, the immobility and intensity of the low-level anticyclone over the East will limit favorable moisture to a narrow, only partially Gulf-modified return-flow corridor through the period. 50s F surface dewpoints -- already common at lower elevations in eastern NM, should mix into the 40s F where diurnal heating is most sustained today over the Plains. Upper 40s to lower 50s dewpoints may persist farther northwest under more persistently cloudy areas, leading to greater RH and lower LCL, but amid cooler surface temperatures. However, at higher elevations, this still may support surface-based effective-inflow parcels. With the coolest midlevel temperatures and strongest DCVA aloft lagging closer to the cyclone core, and mostly behind the low-level cold front, poor midlevel lapse rates will limit buoyancy over the region. This, and lack of richer moisture, should keep MLCAPE generally in the 300-800 J/kg range -- and highly variable depending on elevation and patchy heating/mixing. Vertical shear amid southwest flow aloft will strengthen through the evening along/ahead of the western frontal zone as the cyclone digs into AZ. Enlarging hodographs and low-level shear will accompany a strengthening low-level jet and greater moisture this evening and tonight over much of eastern NM, along/ahead of the slow-moving frontal convective arc. However, this also will coincide with nocturnal boundary-layer stabilization and likely an increasingly messy convective mode. A window of tornado potential may exist from late afternoon into early evening during that transition, especially at higher elevations of the Plains/mesa country, but still appears too isolated and conditional for more than marginal probabilities. ..Edwards/Goss.. 10/18/2024 Read more

000
ABPZ20 KNHC 181153
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Fri Oct 18 2024

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

South of Southwestern Mexico:
An area of low pressure is expected to form in a few days well
offshore of southwestern Mexico. Gradual development is possible
thereafter, and a tropical depression could form around the
middle of next week as the system moves westward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Hogsett/Cangialosi

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CDT Fri Oct 18 2024 Valid 211200Z - 261200Z ...DISCUSSION... For this coming Monday, a shortwave trough is forecast to move into the central Plains. Models indicate that a narrow, and increasingly limited, band of moisture will be present ahead of the trough and associated surface front. Though thunderstorms are possible in parts of eastern Kansas with this activity, severe weather potential appears low at this time. As the central Plains trough moves east, it is expected to lose amplitude and eventually phase with a stronger, broader upper trough moving through the Upper Midwest and Ohio Valley region around the middle of next week. While models begin to diverge on the upper-level pattern at that time, the general consensus is for a cold font to push into parts of the southern Plains as well as to near the Gulf Coast and off the Atlantic Coast. With moisture ahead of the front still looking limited, severe thunderstorms do not appear probable along the boundary. Thereafter, surface ridging in the eastern third of the CONUS, along with another upper ridge over the Divide, will keep severe weather potential low through at least the end of next week and possibly into next weekend. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CDT Fri Oct 18 2024 Valid 211200Z - 261200Z ...DISCUSSION... For this coming Monday, a shortwave trough is forecast to move into the central Plains. Models indicate that a narrow, and increasingly limited, band of moisture will be present ahead of the trough and associated surface front. Though thunderstorms are possible in parts of eastern Kansas with this activity, severe weather potential appears low at this time. As the central Plains trough moves east, it is expected to lose amplitude and eventually phase with a stronger, broader upper trough moving through the Upper Midwest and Ohio Valley region around the middle of next week. While models begin to diverge on the upper-level pattern at that time, the general consensus is for a cold font to push into parts of the southern Plains as well as to near the Gulf Coast and off the Atlantic Coast. With moisture ahead of the front still looking limited, severe thunderstorms do not appear probable along the boundary. Thereafter, surface ridging in the eastern third of the CONUS, along with another upper ridge over the Divide, will keep severe weather potential low through at least the end of next week and possibly into next weekend. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CDT Fri Oct 18 2024 Valid 211200Z - 261200Z ...DISCUSSION... For this coming Monday, a shortwave trough is forecast to move into the central Plains. Models indicate that a narrow, and increasingly limited, band of moisture will be present ahead of the trough and associated surface front. Though thunderstorms are possible in parts of eastern Kansas with this activity, severe weather potential appears low at this time. As the central Plains trough moves east, it is expected to lose amplitude and eventually phase with a stronger, broader upper trough moving through the Upper Midwest and Ohio Valley region around the middle of next week. While models begin to diverge on the upper-level pattern at that time, the general consensus is for a cold font to push into parts of the southern Plains as well as to near the Gulf Coast and off the Atlantic Coast. With moisture ahead of the front still looking limited, severe thunderstorms do not appear probable along the boundary. Thereafter, surface ridging in the eastern third of the CONUS, along with another upper ridge over the Divide, will keep severe weather potential low through at least the end of next week and possibly into next weekend. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CDT Fri Oct 18 2024 Valid 211200Z - 261200Z ...DISCUSSION... For this coming Monday, a shortwave trough is forecast to move into the central Plains. Models indicate that a narrow, and increasingly limited, band of moisture will be present ahead of the trough and associated surface front. Though thunderstorms are possible in parts of eastern Kansas with this activity, severe weather potential appears low at this time. As the central Plains trough moves east, it is expected to lose amplitude and eventually phase with a stronger, broader upper trough moving through the Upper Midwest and Ohio Valley region around the middle of next week. While models begin to diverge on the upper-level pattern at that time, the general consensus is for a cold font to push into parts of the southern Plains as well as to near the Gulf Coast and off the Atlantic Coast. With moisture ahead of the front still looking limited, severe thunderstorms do not appear probable along the boundary. Thereafter, surface ridging in the eastern third of the CONUS, along with another upper ridge over the Divide, will keep severe weather potential low through at least the end of next week and possibly into next weekend. Read more