Severe Storms

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0427 PM CDT Fri Jun 21 2024 Valid 231200Z - 291200Z Increasing mid-level southwesterlies will accompany a north Pacific shortwave trough late this weekend from WA southward across ID. Until then, hot and dry conditions under a mid to upper-level ridge will continue to result in curing/drying of fuels from portions of the Pacific Northwest, Great Basin, and Southwest. Increasing westerly and southwesterly surface winds will develop ahead of and behind a dry cold front moving through WA and OR D3/Sunday. Low critical probabilities have been extended southward to include south-central OR and northwestern NV, where widespread RH of less than 15 percent will combine with 15-20 mph sustained wind speeds. Similar wind speeds, and slightly higher RH, are still anticipated across the Columbia Basin. Critical meteorological conditions appear likely across the Upper Snake Plain of ID D3. However, confidence in the introduction of higher critical probabilities within this region is low considering less receptive fuels. Very similar conditions will follow D4/Monday over the same area. Surface wind speeds will decrease across the Pacific Northwest, the majority of the Great Basin, and Southwest D5/Tuesday, as the mid to upper-level ridge amplifies again over the western CONUS. This decrease will be less noticeable across the Upper Snake Plain, but limited spatial extent of critical speeds does not warrant the introduction of low probabilities at this time. A return to at least locally elevated conditions will be possible D6-D8 across the Great Basin, and perhaps Pacific Northwest, as another upper-level trough and strengthening mid-level flow traverse the northwestern CONUS. Low critical probabilities may need to be introduced in future forecasts within these regions as details regarding more precise wind and RH thresholds emerge. ..Barnes.. 06/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0427 PM CDT Fri Jun 21 2024 Valid 231200Z - 291200Z Increasing mid-level southwesterlies will accompany a north Pacific shortwave trough late this weekend from WA southward across ID. Until then, hot and dry conditions under a mid to upper-level ridge will continue to result in curing/drying of fuels from portions of the Pacific Northwest, Great Basin, and Southwest. Increasing westerly and southwesterly surface winds will develop ahead of and behind a dry cold front moving through WA and OR D3/Sunday. Low critical probabilities have been extended southward to include south-central OR and northwestern NV, where widespread RH of less than 15 percent will combine with 15-20 mph sustained wind speeds. Similar wind speeds, and slightly higher RH, are still anticipated across the Columbia Basin. Critical meteorological conditions appear likely across the Upper Snake Plain of ID D3. However, confidence in the introduction of higher critical probabilities within this region is low considering less receptive fuels. Very similar conditions will follow D4/Monday over the same area. Surface wind speeds will decrease across the Pacific Northwest, the majority of the Great Basin, and Southwest D5/Tuesday, as the mid to upper-level ridge amplifies again over the western CONUS. This decrease will be less noticeable across the Upper Snake Plain, but limited spatial extent of critical speeds does not warrant the introduction of low probabilities at this time. A return to at least locally elevated conditions will be possible D6-D8 across the Great Basin, and perhaps Pacific Northwest, as another upper-level trough and strengthening mid-level flow traverse the northwestern CONUS. Low critical probabilities may need to be introduced in future forecasts within these regions as details regarding more precise wind and RH thresholds emerge. ..Barnes.. 06/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1360 CONCERNING SEVERE THUNDERSTORM WATCH 441... FOR THE FOUR CORNERS AREA AND EASTERN UT VICINITY
Mesoscale Discussion 1360 NWS Storm Prediction Center Norman OK 0311 PM CDT Fri Jun 21 2024 Areas affected...the Four Corners Area and eastern UT vicinity Concerning...Severe Thunderstorm Watch 441... Valid 212011Z - 212145Z The severe weather threat for Severe Thunderstorm Watch 441 continues. SUMMARY...An isolated severe hail and wind threat should continue for the next several hours as single cells and a few supercells spread slowly east-northeastward, mainly affecting the eastern Utah to Four Corners Area. DISCUSSION...Scattered to numerous thunderstorms are ongoing across the eastern Great Basin to southern/central Rockies region. The most intense storm has been a persistent slow-moving supercell along the AZ/UT border area near Page. Significant severe hail from 2-2.5 inches in diameter and even a brief tornado will be possible as this storm moves along the Lake Powell to Glen Canyon vicinity over the next couple hours. A few additional supercells should develop over eastern UT into the Four Corners vicinity amid MLCAPE of 1000-1500 J/kg and effective bulk shear of 40-50 kts. Convection across west-central CO in the Grand Junction vicinity may tend to struggle owing to the limit period of heating between morning convection and renewed development this afternoon. ..Grams.. 06/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABQ...RIW...GJT...FGZ...SLC... LAT...LON 36600889 35540758 35020768 34750859 35421036 36311174 37571201 39321139 40491080 41080939 41020868 38020872 36600889 Read more

WW 0444 Status Updates
STATUS REPORT ON WW 444 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 S POU TO 30 WSW BDL TO 10 SW EEN. ..SQUITIERI..06/21/24 ATTN...WFO...OKX...BOX...ALY... STATUS REPORT FOR WS 444 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-003-007-009-011-013-015-212240- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MAC011-013-015-027-212240- MA . MASSACHUSETTS COUNTIES INCLUDED ARE FRANKLIN HAMPDEN HAMPSHIRE WORCESTER NYC079-212240- NY . NEW YORK COUNTIES INCLUDED ARE PUTNAM Read more

MD 1359 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR MUCH OF CENTRAL NEBRASKA
Mesoscale Discussion 1359 NWS Storm Prediction Center Norman OK 0255 PM CDT Fri Jun 21 2024 Areas affected...Much of Central Nebraska Concerning...Severe potential...Watch likely Valid 211955Z - 212130Z Probability of Watch Issuance...80 percent SUMMARY...Convective initiation is expected in the next couple of hours in a region of enhanced ascent near a surface low in SW NE. A severe thunderstorm watch is likely needed for damaging winds and large hail into this evening. DISCUSSION...A surface cyclone has developed in SW NE along a stationary front, with a region of cumulus development located just south of the cyclone center in far NW KS. Surface temperatures have warmed into the low 90s F, with dewpoints in the mid 60s F in NW KS, increasing into the upper 60s F along and N of the surface boundary in NE. SPC Mesoanalysis shows MLCAPE > 1500 J/kg, with deep layer shear in the 35-40kt range, increasing to 45 kts N of the boundary. Convective initiation is expected within the 20-21Z time frame in far NW KS and SW NE, spreading NE along the stationary front. Given the large surface T/Td spreads, along with RAP forecast profiles showing a deep, well-mixed boundary layer and some curvature of the hodograph, the primary threat appears to be for damaging straight-line winds and large hail. Uncertainty remains in storm mode and coverage, especially further southeast of the boundary. However, a severe thunderstorm watch is likely for much of the discussion area. ..Halbert/Weinman/Hart.. 06/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...OAX...GID...LBF...GLD...BOU... LAT...LON 40090207 40330220 40540220 40740223 40930226 41190218 41450190 41680169 41830143 41990107 42130080 42290035 42420004 42549973 42659924 42779875 42839805 42889744 42879689 42779658 42549641 42279641 42059643 41789677 41509717 41299754 41089789 40979810 40859828 40699873 40569908 40419939 40319972 40190004 40060045 39860091 39740129 39680178 39800193 40090207 Read more

WW 0442 Status Updates
STATUS REPORT ON WW 442 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..WEINMAN..06/21/24 ATTN...WFO...TFX...BYZ...GGW... STATUS REPORT FOR WS 442 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC005-013-015-027-035-037-041-045-051-059-065-069-073-099-101- 107-212140- MT . MONTANA COUNTIES INCLUDED ARE BLAINE CASCADE CHOUTEAU FERGUS GLACIER GOLDEN VALLEY HILL JUDITH BASIN LIBERTY MEAGHER MUSSELSHELL PETROLEUM PONDERA TETON TOOLE WHEATLAND THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0442 Status Updates
STATUS REPORT ON WW 442 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..WEINMAN..06/21/24 ATTN...WFO...TFX...BYZ...GGW... STATUS REPORT FOR WS 442 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC005-013-015-027-035-037-041-045-051-059-065-069-073-099-101- 107-212140- MT . MONTANA COUNTIES INCLUDED ARE BLAINE CASCADE CHOUTEAU FERGUS GLACIER GOLDEN VALLEY HILL JUDITH BASIN LIBERTY MEAGHER MUSSELSHELL PETROLEUM PONDERA TETON TOOLE WHEATLAND THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

MD 1358 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR CENTRAL AND EASTERN WYOMING...INTO FAR SOUTHERN MONTANA
Mesoscale Discussion 1358 NWS Storm Prediction Center Norman OK 0156 PM CDT Fri Jun 21 2024 Areas affected...Central and Eastern Wyoming...into far Southern Montana Concerning...Severe potential...Watch likely Valid 211856Z - 212100Z Probability of Watch Issuance...95 percent SUMMARY...Weather watch issuance may be needed within the next couple of hours as storm coverage increases over the high terrain of W WY, with additional development happening further east along the Laramie range in SE WY. Primary expected hazards are for damaging winds and hail. DISCUSSION...Thunderstorm coverage has increased over W WY beneath a broad upper trough, with surface temperatures warming into the mid-to-upper 70s F out ahead in Central WY. Dewpoints in the mid-to-upper 50s F have spread northward along the front range of the Rockies in Eastern WY as lee troughing beneath the upper wave continues, with some dewpoints in the upper 40s to low 50s F reaching into Central WY. This warm/moist boundary-layer air, coupled with steep mid-level lapse rates of 8-9 C/km, has resulted in SPC Mesoanalysis MLCAPE values of 1000-1500 J/kg. This buoyancy is colocated with deep layer shear values in the 40-50 kt range, indicating organized multicell clusters and supercells are possible. As daytime heating and moisture transport continues out ahead of developing convection, combinations of buoyancy and shear will continue to support a supercell threat. Primarily straight-line hodographs over W WY should support splitting supercells, and coupled with abundant storm coverage, indicates the potential for plentiful thunderstorm and outflow interactions that result in primarily a damaging wind and hail threat. However, a brief tornado cannot be ruled out in SE WY, where surface winds are locally backed to the east. Additionally, RAP forecast profiles in NE WY show potential for locally backed flow and curved hodographs later this evening, though uncertainty in overall storm coverage and mode may preclude a more robust tornado threat. Overall, the eastward extent of severe hazards appears to be limited due to convective inhibition increasing during the afternoon and evening, largely due to subsidence behind a 500mb vort max exiting NE CO/SW NE. Severe thunderstorm watch issuance is expected between 19-20Z, primarily for 70 MPH winds and 2 inch hail. ..Halbert/Weinman/Hart.. 06/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...UNR...CYS...BYZ...RIW... LAT...LON 44550824 44840831 45220818 45450778 45450727 45480675 45450604 45410525 45270477 45010433 44650407 44370397 43930387 43500387 43130387 42610387 42160396 41730409 41520431 41290464 41150537 41250624 41650679 42220712 42730746 43030763 43350775 43740788 44140802 44550824 Read more

WW 0443 Status Updates
STATUS REPORT ON WW 443 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1358 ..WEINMAN..06/21/24 ATTN...WFO...BOU...BYZ...CYS...RIW...UNR... STATUS REPORT FOR WS 443 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC069-123-212140- CO . COLORADO COUNTIES INCLUDED ARE LARIMER WELD MTC003-212140- MT . MONTANA COUNTIES INCLUDED ARE BIG HORN NEC007-105-157-165-212140- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER KIMBALL SCOTTS BLUFF SIOUX Read more

WW 0443 Status Updates
STATUS REPORT ON WW 443 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1358 ..WEINMAN..06/21/24 ATTN...WFO...BOU...BYZ...CYS...RIW...UNR... STATUS REPORT FOR WS 443 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC069-123-212140- CO . COLORADO COUNTIES INCLUDED ARE LARIMER WELD MTC003-212140- MT . MONTANA COUNTIES INCLUDED ARE BIG HORN NEC007-105-157-165-212140- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER KIMBALL SCOTTS BLUFF SIOUX Read more

WW 0445 Status Updates
STATUS FOR WATCH 0445 HAS NOT BEEN ISSUED YET Read more

WW 0445 Status Updates
STATUS FOR WATCH 0445 HAS NOT BEEN ISSUED YET Read more

WW 0441 Status Updates
STATUS REPORT ON WW 441 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1360. ..GRAMS..06/21/24 ATTN...WFO...GJT...ABQ...SLC...RIW... STATUS REPORT FOR WS 441 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC029-033-045-067-077-081-083-085-091-103-111-113-212140- CO . COLORADO COUNTIES INCLUDED ARE DELTA DOLORES GARFIELD LA PLATA MESA MOFFAT MONTEZUMA MONTROSE OURAY RIO BLANCO SAN JUAN SAN MIGUEL NMC006-031-045-212140- NM . NEW MEXICO COUNTIES INCLUDED ARE CIBOLA MCKINLEY SAN JUAN UTC007-009-013-015-017-019-025-031-037-039-041-047-051-055- 212140- UT . UTAH COUNTIES INCLUDED ARE Read more

WW 0441 Status Updates
STATUS REPORT ON WW 441 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1360. ..GRAMS..06/21/24 ATTN...WFO...GJT...ABQ...SLC...RIW... STATUS REPORT FOR WS 441 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC029-033-045-067-077-081-083-085-091-103-111-113-212140- CO . COLORADO COUNTIES INCLUDED ARE DELTA DOLORES GARFIELD LA PLATA MESA MOFFAT MONTEZUMA MONTROSE OURAY RIO BLANCO SAN JUAN SAN MIGUEL NMC006-031-045-212140- NM . NEW MEXICO COUNTIES INCLUDED ARE CIBOLA MCKINLEY SAN JUAN UTC007-009-013-015-017-019-025-031-037-039-041-047-051-055- 212140- UT . UTAH COUNTIES INCLUDED ARE Read more

MD 1356 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF THE MID-MO TO UPPER MS VALLEY
Mesoscale Discussion 1356 NWS Storm Prediction Center Norman OK 0125 PM CDT Fri Jun 21 2024 Areas affected...parts of the Mid-MO to Upper MS Valley Concerning...Severe potential...Watch possible Valid 211825Z - 212030Z Probability of Watch Issuance...40 percent SUMMARY...A generally isolated severe threat should develop into late afternoon with a mix of wind/hail, along with a couple tornadoes possible. Uncertainty exists with the overall spatial extent of the severe threat with slow-moving storms expected. DISCUSSION...Convection is slowly increasing along a quasi-stationary/slow-moving warm front that arcs from northeast NE into far southeast MN and southwest WI. The eastern portion of this development appears to be primarily driven by modest low-level warm theta-e advection within an uncapped, moderately buoyant air mass. Convection farther west over the Mid-MO Valley is also being aided by a minor MCV in southeast SD. Area VWPs still indicate relatively stronger mid/upper flow is likely displaced along and to the cool side of the front, with weak flow into the warm-moist sector. A confined corridor of slow-moving, transient supercells and multicell clusters should develop near and just south of the front. Overall severe coverage will probably remain sporadic with mainly a lower-end wind/hail threat. Confidence is somewhat higher in intensification, including the potential for a couple tornadoes, in association with the MCV over the Mid-MO Valley. ..Grams/Hart.. 06/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MKX...DVN...ARX...MPX...DMX...FSD...OAX...LBF... LAT...LON 44379225 43909048 43159028 42659136 42609154 42749384 42489615 42449837 42599907 43169904 43359876 43749576 44379225 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Fri Jun 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY...THE FOUR CORNERS REGION...AND SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered strong to severe storms are expected from parts the upper Mississippi Valley into the northern High Plains, and into the Four Corners vicinity. A few strong storms may occur from parts of the Lower Great Lakes to southern New England. ...Discussion... Only two notable changes were made to the previous convective outlook. Otherwise the previous forecast thinking remains on track. 1) Have increased severe-wind probabilities to 15 percent and a categorical Slight Risk over southern portions of New England. Despite modest deep-layer westerly flow, steep 0-3 km lapse rates (7.5 to 8.5 deg C/km) and around 2 inches PW have yielded an environment that will favor multicells sporadically capable of strong to locally severe gusts (50-65 mph) and wind damage. A linear cluster near the NY/MA/CT border will likely push eastward over the next 2-4 hours and reach the CT/RI coast, and this area has been highlighted with recently issued Severe Thunderstorm Watch #444. 2) Included southwest NE in Slight-Risk equivalent severe wind probabilities based on the latest satellite/observational trends. Storms that potentially develop over the next few hours within southwest NE may yield a severe-wind hazard given the steep lapse rate environment. ..Smith.. 06/21/2024 .PREV DISCUSSION... /ISSUED 1052 AM CDT Fri Jun 21 2024/ ...Four Corners into WY... Water vapor imagery shows a well-defined upper trough over NV, with an associated 40+kt mid-level speed max tracking from northern AZ into UT/CO. Beneath this strengthening wind field and large-scale ascent, considerable low-level moisture is present today with dewpoints in the 50s across much eastern UT/western CO and southwest WY. Pockets of strong daytime heating will lead to scattered afternoon thunderstorms. Vertical shear profiles will promote supercell storm structures capable of hail and damaging winds for several hours this afternoon and evening. ...MT/WY... Several weak shortwave troughs are noted this morning moving east-northeastward across the northern Rockies. These features, combined with persistent easterly low-level winds across central/eastern MT will result in scattered afternoon thunderstorm development. Relatively isolated supercells are expected over MT, with more convective coverage farther south into eastern WY and western SD/NE. Storms will be capable of large hail and damaging winds, along with the possibility of a tornado or two (mainly over parts of MT). ...Central Plains... A well-defined surface boundary extends across northern NE into southern MN. Considerable heating to the south of this boundary, along with strengthening southerly low-level winds/convergence by late afternoon, will result in scattered thunderstorms in vicinity of the front. Sufficient flow aloft and ample CAPE will promote a risk of a few severe storms capable of damaging winds and hail. ...Lower MI... Pockets of strong heating will lead to scattered afternoon thunderstorms over parts of central and southern Lower MI. This area is along the southern fringe of stronger westerlies, with 25-30 knots of flow at 500mb. This might be sufficient for a few strong storms capable of gusty winds and hail. ...NY/PA/Southern New England... Hot and humid conditions are expected today across much of PA/NY and southern New England, with dewpoints in the 70s and temperatures well into the 80s and 90s. Mid level lapse rates are rather weak, so MLCAPE values will be <2000 J/kg. Given relatively weak winds aloft, thunderstorm organization is expected to be marginal. Nevertheless, a few strong storms capable of locally gusty/damaging winds are possible through the afternoon. Please refer to MCD #1352 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Fri Jun 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY...THE FOUR CORNERS REGION...AND SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered strong to severe storms are expected from parts the upper Mississippi Valley into the northern High Plains, and into the Four Corners vicinity. A few strong storms may occur from parts of the Lower Great Lakes to southern New England. ...Discussion... Only two notable changes were made to the previous convective outlook. Otherwise the previous forecast thinking remains on track. 1) Have increased severe-wind probabilities to 15 percent and a categorical Slight Risk over southern portions of New England. Despite modest deep-layer westerly flow, steep 0-3 km lapse rates (7.5 to 8.5 deg C/km) and around 2 inches PW have yielded an environment that will favor multicells sporadically capable of strong to locally severe gusts (50-65 mph) and wind damage. A linear cluster near the NY/MA/CT border will likely push eastward over the next 2-4 hours and reach the CT/RI coast, and this area has been highlighted with recently issued Severe Thunderstorm Watch #444. 2) Included southwest NE in Slight-Risk equivalent severe wind probabilities based on the latest satellite/observational trends. Storms that potentially develop over the next few hours within southwest NE may yield a severe-wind hazard given the steep lapse rate environment. ..Smith.. 06/21/2024 .PREV DISCUSSION... /ISSUED 1052 AM CDT Fri Jun 21 2024/ ...Four Corners into WY... Water vapor imagery shows a well-defined upper trough over NV, with an associated 40+kt mid-level speed max tracking from northern AZ into UT/CO. Beneath this strengthening wind field and large-scale ascent, considerable low-level moisture is present today with dewpoints in the 50s across much eastern UT/western CO and southwest WY. Pockets of strong daytime heating will lead to scattered afternoon thunderstorms. Vertical shear profiles will promote supercell storm structures capable of hail and damaging winds for several hours this afternoon and evening. ...MT/WY... Several weak shortwave troughs are noted this morning moving east-northeastward across the northern Rockies. These features, combined with persistent easterly low-level winds across central/eastern MT will result in scattered afternoon thunderstorm development. Relatively isolated supercells are expected over MT, with more convective coverage farther south into eastern WY and western SD/NE. Storms will be capable of large hail and damaging winds, along with the possibility of a tornado or two (mainly over parts of MT). ...Central Plains... A well-defined surface boundary extends across northern NE into southern MN. Considerable heating to the south of this boundary, along with strengthening southerly low-level winds/convergence by late afternoon, will result in scattered thunderstorms in vicinity of the front. Sufficient flow aloft and ample CAPE will promote a risk of a few severe storms capable of damaging winds and hail. ...Lower MI... Pockets of strong heating will lead to scattered afternoon thunderstorms over parts of central and southern Lower MI. This area is along the southern fringe of stronger westerlies, with 25-30 knots of flow at 500mb. This might be sufficient for a few strong storms capable of gusty winds and hail. ...NY/PA/Southern New England... Hot and humid conditions are expected today across much of PA/NY and southern New England, with dewpoints in the 70s and temperatures well into the 80s and 90s. Mid level lapse rates are rather weak, so MLCAPE values will be <2000 J/kg. Given relatively weak winds aloft, thunderstorm organization is expected to be marginal. Nevertheless, a few strong storms capable of locally gusty/damaging winds are possible through the afternoon. Please refer to MCD #1352 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Fri Jun 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY...THE FOUR CORNERS REGION...AND SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered strong to severe storms are expected from parts the upper Mississippi Valley into the northern High Plains, and into the Four Corners vicinity. A few strong storms may occur from parts of the Lower Great Lakes to southern New England. ...Discussion... Only two notable changes were made to the previous convective outlook. Otherwise the previous forecast thinking remains on track. 1) Have increased severe-wind probabilities to 15 percent and a categorical Slight Risk over southern portions of New England. Despite modest deep-layer westerly flow, steep 0-3 km lapse rates (7.5 to 8.5 deg C/km) and around 2 inches PW have yielded an environment that will favor multicells sporadically capable of strong to locally severe gusts (50-65 mph) and wind damage. A linear cluster near the NY/MA/CT border will likely push eastward over the next 2-4 hours and reach the CT/RI coast, and this area has been highlighted with recently issued Severe Thunderstorm Watch #444. 2) Included southwest NE in Slight-Risk equivalent severe wind probabilities based on the latest satellite/observational trends. Storms that potentially develop over the next few hours within southwest NE may yield a severe-wind hazard given the steep lapse rate environment. ..Smith.. 06/21/2024 .PREV DISCUSSION... /ISSUED 1052 AM CDT Fri Jun 21 2024/ ...Four Corners into WY... Water vapor imagery shows a well-defined upper trough over NV, with an associated 40+kt mid-level speed max tracking from northern AZ into UT/CO. Beneath this strengthening wind field and large-scale ascent, considerable low-level moisture is present today with dewpoints in the 50s across much eastern UT/western CO and southwest WY. Pockets of strong daytime heating will lead to scattered afternoon thunderstorms. Vertical shear profiles will promote supercell storm structures capable of hail and damaging winds for several hours this afternoon and evening. ...MT/WY... Several weak shortwave troughs are noted this morning moving east-northeastward across the northern Rockies. These features, combined with persistent easterly low-level winds across central/eastern MT will result in scattered afternoon thunderstorm development. Relatively isolated supercells are expected over MT, with more convective coverage farther south into eastern WY and western SD/NE. Storms will be capable of large hail and damaging winds, along with the possibility of a tornado or two (mainly over parts of MT). ...Central Plains... A well-defined surface boundary extends across northern NE into southern MN. Considerable heating to the south of this boundary, along with strengthening southerly low-level winds/convergence by late afternoon, will result in scattered thunderstorms in vicinity of the front. Sufficient flow aloft and ample CAPE will promote a risk of a few severe storms capable of damaging winds and hail. ...Lower MI... Pockets of strong heating will lead to scattered afternoon thunderstorms over parts of central and southern Lower MI. This area is along the southern fringe of stronger westerlies, with 25-30 knots of flow at 500mb. This might be sufficient for a few strong storms capable of gusty winds and hail. ...NY/PA/Southern New England... Hot and humid conditions are expected today across much of PA/NY and southern New England, with dewpoints in the 70s and temperatures well into the 80s and 90s. Mid level lapse rates are rather weak, so MLCAPE values will be <2000 J/kg. Given relatively weak winds aloft, thunderstorm organization is expected to be marginal. Nevertheless, a few strong storms capable of locally gusty/damaging winds are possible through the afternoon. Please refer to MCD #1352 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Fri Jun 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY...THE FOUR CORNERS REGION...AND SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered strong to severe storms are expected from parts the upper Mississippi Valley into the northern High Plains, and into the Four Corners vicinity. A few strong storms may occur from parts of the Lower Great Lakes to southern New England. ...Discussion... Only two notable changes were made to the previous convective outlook. Otherwise the previous forecast thinking remains on track. 1) Have increased severe-wind probabilities to 15 percent and a categorical Slight Risk over southern portions of New England. Despite modest deep-layer westerly flow, steep 0-3 km lapse rates (7.5 to 8.5 deg C/km) and around 2 inches PW have yielded an environment that will favor multicells sporadically capable of strong to locally severe gusts (50-65 mph) and wind damage. A linear cluster near the NY/MA/CT border will likely push eastward over the next 2-4 hours and reach the CT/RI coast, and this area has been highlighted with recently issued Severe Thunderstorm Watch #444. 2) Included southwest NE in Slight-Risk equivalent severe wind probabilities based on the latest satellite/observational trends. Storms that potentially develop over the next few hours within southwest NE may yield a severe-wind hazard given the steep lapse rate environment. ..Smith.. 06/21/2024 .PREV DISCUSSION... /ISSUED 1052 AM CDT Fri Jun 21 2024/ ...Four Corners into WY... Water vapor imagery shows a well-defined upper trough over NV, with an associated 40+kt mid-level speed max tracking from northern AZ into UT/CO. Beneath this strengthening wind field and large-scale ascent, considerable low-level moisture is present today with dewpoints in the 50s across much eastern UT/western CO and southwest WY. Pockets of strong daytime heating will lead to scattered afternoon thunderstorms. Vertical shear profiles will promote supercell storm structures capable of hail and damaging winds for several hours this afternoon and evening. ...MT/WY... Several weak shortwave troughs are noted this morning moving east-northeastward across the northern Rockies. These features, combined with persistent easterly low-level winds across central/eastern MT will result in scattered afternoon thunderstorm development. Relatively isolated supercells are expected over MT, with more convective coverage farther south into eastern WY and western SD/NE. Storms will be capable of large hail and damaging winds, along with the possibility of a tornado or two (mainly over parts of MT). ...Central Plains... A well-defined surface boundary extends across northern NE into southern MN. Considerable heating to the south of this boundary, along with strengthening southerly low-level winds/convergence by late afternoon, will result in scattered thunderstorms in vicinity of the front. Sufficient flow aloft and ample CAPE will promote a risk of a few severe storms capable of damaging winds and hail. ...Lower MI... Pockets of strong heating will lead to scattered afternoon thunderstorms over parts of central and southern Lower MI. This area is along the southern fringe of stronger westerlies, with 25-30 knots of flow at 500mb. This might be sufficient for a few strong storms capable of gusty winds and hail. ...NY/PA/Southern New England... Hot and humid conditions are expected today across much of PA/NY and southern New England, with dewpoints in the 70s and temperatures well into the 80s and 90s. Mid level lapse rates are rather weak, so MLCAPE values will be <2000 J/kg. Given relatively weak winds aloft, thunderstorm organization is expected to be marginal. Nevertheless, a few strong storms capable of locally gusty/damaging winds are possible through the afternoon. Please refer to MCD #1352 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Fri Jun 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY...THE FOUR CORNERS REGION...AND SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered strong to severe storms are expected from parts the upper Mississippi Valley into the northern High Plains, and into the Four Corners vicinity. A few strong storms may occur from parts of the Lower Great Lakes to southern New England. ...Discussion... Only two notable changes were made to the previous convective outlook. Otherwise the previous forecast thinking remains on track. 1) Have increased severe-wind probabilities to 15 percent and a categorical Slight Risk over southern portions of New England. Despite modest deep-layer westerly flow, steep 0-3 km lapse rates (7.5 to 8.5 deg C/km) and around 2 inches PW have yielded an environment that will favor multicells sporadically capable of strong to locally severe gusts (50-65 mph) and wind damage. A linear cluster near the NY/MA/CT border will likely push eastward over the next 2-4 hours and reach the CT/RI coast, and this area has been highlighted with recently issued Severe Thunderstorm Watch #444. 2) Included southwest NE in Slight-Risk equivalent severe wind probabilities based on the latest satellite/observational trends. Storms that potentially develop over the next few hours within southwest NE may yield a severe-wind hazard given the steep lapse rate environment. ..Smith.. 06/21/2024 .PREV DISCUSSION... /ISSUED 1052 AM CDT Fri Jun 21 2024/ ...Four Corners into WY... Water vapor imagery shows a well-defined upper trough over NV, with an associated 40+kt mid-level speed max tracking from northern AZ into UT/CO. Beneath this strengthening wind field and large-scale ascent, considerable low-level moisture is present today with dewpoints in the 50s across much eastern UT/western CO and southwest WY. Pockets of strong daytime heating will lead to scattered afternoon thunderstorms. Vertical shear profiles will promote supercell storm structures capable of hail and damaging winds for several hours this afternoon and evening. ...MT/WY... Several weak shortwave troughs are noted this morning moving east-northeastward across the northern Rockies. These features, combined with persistent easterly low-level winds across central/eastern MT will result in scattered afternoon thunderstorm development. Relatively isolated supercells are expected over MT, with more convective coverage farther south into eastern WY and western SD/NE. Storms will be capable of large hail and damaging winds, along with the possibility of a tornado or two (mainly over parts of MT). ...Central Plains... A well-defined surface boundary extends across northern NE into southern MN. Considerable heating to the south of this boundary, along with strengthening southerly low-level winds/convergence by late afternoon, will result in scattered thunderstorms in vicinity of the front. Sufficient flow aloft and ample CAPE will promote a risk of a few severe storms capable of damaging winds and hail. ...Lower MI... Pockets of strong heating will lead to scattered afternoon thunderstorms over parts of central and southern Lower MI. This area is along the southern fringe of stronger westerlies, with 25-30 knots of flow at 500mb. This might be sufficient for a few strong storms capable of gusty winds and hail. ...NY/PA/Southern New England... Hot and humid conditions are expected today across much of PA/NY and southern New England, with dewpoints in the 70s and temperatures well into the 80s and 90s. Mid level lapse rates are rather weak, so MLCAPE values will be <2000 J/kg. Given relatively weak winds aloft, thunderstorm organization is expected to be marginal. Nevertheless, a few strong storms capable of locally gusty/damaging winds are possible through the afternoon. Please refer to MCD #1352 for further details. Read more