Severe Storms

MD 1691 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN MN...WESTERN/CENTRAL IA
Mesoscale Discussion 1691 NWS Storm Prediction Center Norman OK 0356 PM CDT Sat Aug 10 2019 Areas affected...Southern MN...Western/central IA Concerning...Severe potential...Watch unlikely Valid 102056Z - 102300Z Probability of Watch Issuance...20 percent SUMMARY...At least isolated thunderstorm development is possible this afternoon. The strongest cells will be capable of producing locally damaging wind and perhaps a tornado or two. Due to uncertainty regarding the coverage of the threat, watch issuance is currently considered unlikely. DISCUSSION...The latest surface analysis depicts a weak surface low across southwest MN, with a surface boundary extending eastward across southern MN and then southeastward into northeastern IA. A zone of weakly confluent flow, likely related to differential heating, is also noted extending south of the low into western IA. Widespread cloudiness has limited heating across the region, but rich low-level moisture is supporting MLCAPE ranging from 500 J/kg across the eastern portion of the MCD area to around 2000 J/kg across the western portion. Thunderstorm development will be possible later this afternoon near these surface features, with the greatest threat likely near the confluence zone across northwest/north-central IA where somewhat greater destabilization is occurring. Moderate mid/upper-level flow is resulting in effective shear of 40-50 kt across the region, more than sufficient for organized storm structures (including supercells) should convection develop. Warm midlevel temperatures and generally weak midlevel lapse rates are likely to mitigate the severe threat (especially hail) to some extent, but eventual development of one or two supercells is possible. Locally damaging wind would be the primary threat, but a tornado or two would also be possible, given favorable boundary-layer moisture and marginally supportive low-level shear profiles. Watch issuance is currently considered unlikely due to uncertainty regarding the number of storms that can develop across this region. However, this will be re-evaluated if multiple organized cells appear imminent. ..Dean/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...DMX...FSD... LAT...LON 41379495 42219508 43389523 44169532 44389491 44339399 44029329 42499301 41769330 41539377 41379495 Read more

WW 0567 Status Updates
STATUS REPORT ON WW 567 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..EDWARDS..08/10/19 ATTN...WFO...BOI...MSO...PIH...TFX... STATUS REPORT FOR WS 567 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IDC001-003-015-027-035-037-039-045-049-059-073-075-085-087- 102140- ID . IDAHO COUNTIES INCLUDED ARE ADA ADAMS BOISE CANYON CLEARWATER CUSTER ELMORE GEM IDAHO LEMHI OWYHEE PAYETTE VALLEY WASHINGTON MTC001-007-023-027-031-039-043-045-049-057-059-061-063-077-081- 093-102140- MT . MONTANA COUNTIES INCLUDED ARE BEAVERHEAD BROADWATER DEER LODGE FERGUS GALLATIN GRANITE JEFFERSON JUDITH BASIN LEWIS AND CLARK MADISON MEAGHER MINERAL MISSOULA POWELL RAVALLI SILVER BOW Read more

MD 1690 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHWEST ND...WESTERN SD
Mesoscale Discussion 1690 NWS Storm Prediction Center Norman OK 0256 PM CDT Sat Aug 10 2019 Areas affected...Southwest ND...Western SD Concerning...Severe potential...Watch possible Valid 101956Z - 102130Z Probability of Watch Issuance...40 percent SUMMARY...Isolated severe thunderstorms capable of large hail and severe wind will continue into late afternoon. The need for a watch is uncertain due to the limited areal coverage of the threat. DISCUSSION...A supercell has recently developed across southwest ND, with other cells attempting to develop across northeast SD, and further south over the Black Hills. Ongoing convection is being aided by moderate buoyancy (MLCAPE of 1000-1500 J/kg) and effective shear of 35-45 kt, which will continue to support a threat of isolated supercells posing a risk of large hail, severe wind gusts, and perhaps a brief tornado. The airmass downstream of ongoing activity is noticeably cooler and more stable. Thus, the eastward extent of the threat may be relatively limited, with cells exhibiting more of a rightward motion (such as the cell in southwest ND) having more of a residence time within the generally uncapped and more favorable environment. The constrained area of the threat may preclude watch issuance, though at least a couple supercells will be possible into late afternoon across a portion of the region. ..Dean/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR... LAT...LON 43640369 44580375 45740326 46580260 46800231 46810193 46610161 46290146 45570162 44600197 43610247 43540320 43640369 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0242 PM CDT Sat Aug 10 2019 Valid 111200Z - 121200Z The elevated was extended eastward into portions of central Wyoming, as the latest model guidance depicts 15-25 mph sustained westerly surface winds and corresponding 15-25% RH overlapping drier fuels here, particularly for the lower terrain areas. In addition, a few dry lightning strikes may occur within the broader area of thunderstorm activity near the Idaho/Montana border. However, the potential for Day 1 precipitation accumulation, and heavy rain from the Day 2 round, may temper the lightning-induced wildfire spread threat, thus precluding an isolated dry thunderstorm delineation at this time. Otherwise, the previous forecast remains generally on track (see below for details). ..Squitieri.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1247 AM CDT Sat Aug 10 2019/ ...Synopsis... Fire weather conditions will gradually improve some as a persistent West Coast mid-level low weakens and migrates northeastward toward the central Rockies. Most of the thunderstorm potential evident over OR/CA and vicinity the past few days will lessen in the midst of subsidence aloft west of the mid-level trough. Meanwhile, slackening flow aloft over the Great Basin will result in weaker winds and a lessened (locally elevated) fire weather threat in these areas. A lingering risk of elevated fire weather will extend from eastern Idaho into western Wyoming Sunday afternoon. ...Eastern Idaho, far northern Utah, and western Wyoming... As the mid-level wave ejects northeastward, a belt of enhanced mid-level flow will migrate away from the western Great Basin and reach the discussion area during peak heating hours. Vertical mixing processes beneath this flow will result in areas of 15-25 mph westerly surface flow for several hours. RH values will only flirt with critical thresholds on a limited/localized basis, however, and should mitigate the overall fire risk. Dry fuels should continue to support a risk of fire spread especially with ongoing fires, however. An isolated thunderstorm may also occur especially in eastern Idaho and vicinity, though coverage atop dry fuels currently does not warrant any dry thunder delineations for this outlook. ...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 0242 PM CDT Sat Aug 10 2019 Valid 111200Z - 121200Z The elevated was extended eastward into portions of central Wyoming, as the latest model guidance depicts 15-25 mph sustained westerly surface winds and corresponding 15-25% RH overlapping drier fuels here, particularly for the lower terrain areas. In addition, a few dry lightning strikes may occur within the broader area of thunderstorm activity near the Idaho/Montana border. However, the potential for Day 1 precipitation accumulation, and heavy rain from the Day 2 round, may temper the lightning-induced wildfire spread threat, thus precluding an isolated dry thunderstorm delineation at this time. Otherwise, the previous forecast remains generally on track (see below for details). ..Squitieri.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1247 AM CDT Sat Aug 10 2019/ ...Synopsis... Fire weather conditions will gradually improve some as a persistent West Coast mid-level low weakens and migrates northeastward toward the central Rockies. Most of the thunderstorm potential evident over OR/CA and vicinity the past few days will lessen in the midst of subsidence aloft west of the mid-level trough. Meanwhile, slackening flow aloft over the Great Basin will result in weaker winds and a lessened (locally elevated) fire weather threat in these areas. A lingering risk of elevated fire weather will extend from eastern Idaho into western Wyoming Sunday afternoon. ...Eastern Idaho, far northern Utah, and western Wyoming... As the mid-level wave ejects northeastward, a belt of enhanced mid-level flow will migrate away from the western Great Basin and reach the discussion area during peak heating hours. Vertical mixing processes beneath this flow will result in areas of 15-25 mph westerly surface flow for several hours. RH values will only flirt with critical thresholds on a limited/localized basis, however, and should mitigate the overall fire risk. Dry fuels should continue to support a risk of fire spread especially with ongoing fires, however. An isolated thunderstorm may also occur especially in eastern Idaho and vicinity, though coverage atop dry fuels currently does not warrant any dry thunder delineations for this outlook. ...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 0242 PM CDT Sat Aug 10 2019 Valid 111200Z - 121200Z The elevated was extended eastward into portions of central Wyoming, as the latest model guidance depicts 15-25 mph sustained westerly surface winds and corresponding 15-25% RH overlapping drier fuels here, particularly for the lower terrain areas. In addition, a few dry lightning strikes may occur within the broader area of thunderstorm activity near the Idaho/Montana border. However, the potential for Day 1 precipitation accumulation, and heavy rain from the Day 2 round, may temper the lightning-induced wildfire spread threat, thus precluding an isolated dry thunderstorm delineation at this time. Otherwise, the previous forecast remains generally on track (see below for details). ..Squitieri.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1247 AM CDT Sat Aug 10 2019/ ...Synopsis... Fire weather conditions will gradually improve some as a persistent West Coast mid-level low weakens and migrates northeastward toward the central Rockies. Most of the thunderstorm potential evident over OR/CA and vicinity the past few days will lessen in the midst of subsidence aloft west of the mid-level trough. Meanwhile, slackening flow aloft over the Great Basin will result in weaker winds and a lessened (locally elevated) fire weather threat in these areas. A lingering risk of elevated fire weather will extend from eastern Idaho into western Wyoming Sunday afternoon. ...Eastern Idaho, far northern Utah, and western Wyoming... As the mid-level wave ejects northeastward, a belt of enhanced mid-level flow will migrate away from the western Great Basin and reach the discussion area during peak heating hours. Vertical mixing processes beneath this flow will result in areas of 15-25 mph westerly surface flow for several hours. RH values will only flirt with critical thresholds on a limited/localized basis, however, and should mitigate the overall fire risk. Dry fuels should continue to support a risk of fire spread especially with ongoing fires, however. An isolated thunderstorm may also occur especially in eastern Idaho and vicinity, though coverage atop dry fuels currently does not warrant any dry thunder delineations for this outlook. ...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 0242 PM CDT Sat Aug 10 2019 Valid 111200Z - 121200Z The elevated was extended eastward into portions of central Wyoming, as the latest model guidance depicts 15-25 mph sustained westerly surface winds and corresponding 15-25% RH overlapping drier fuels here, particularly for the lower terrain areas. In addition, a few dry lightning strikes may occur within the broader area of thunderstorm activity near the Idaho/Montana border. However, the potential for Day 1 precipitation accumulation, and heavy rain from the Day 2 round, may temper the lightning-induced wildfire spread threat, thus precluding an isolated dry thunderstorm delineation at this time. Otherwise, the previous forecast remains generally on track (see below for details). ..Squitieri.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1247 AM CDT Sat Aug 10 2019/ ...Synopsis... Fire weather conditions will gradually improve some as a persistent West Coast mid-level low weakens and migrates northeastward toward the central Rockies. Most of the thunderstorm potential evident over OR/CA and vicinity the past few days will lessen in the midst of subsidence aloft west of the mid-level trough. Meanwhile, slackening flow aloft over the Great Basin will result in weaker winds and a lessened (locally elevated) fire weather threat in these areas. A lingering risk of elevated fire weather will extend from eastern Idaho into western Wyoming Sunday afternoon. ...Eastern Idaho, far northern Utah, and western Wyoming... As the mid-level wave ejects northeastward, a belt of enhanced mid-level flow will migrate away from the western Great Basin and reach the discussion area during peak heating hours. Vertical mixing processes beneath this flow will result in areas of 15-25 mph westerly surface flow for several hours. RH values will only flirt with critical thresholds on a limited/localized basis, however, and should mitigate the overall fire risk. Dry fuels should continue to support a risk of fire spread especially with ongoing fires, however. An isolated thunderstorm may also occur especially in eastern Idaho and vicinity, though coverage atop dry fuels currently does not warrant any dry thunder delineations for this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0235 PM CDT Sat Aug 10 2019 Valid 102000Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF ID/MT/WY AND EASTERN NC... ...SUMMARY... Scattered severe thunderstorms with large hail and damaging wind gusts are most likely across parts of Idaho, Montana, Wyoming, and eastern North Carolina. The severe threat should be greatest during the late afternoon to early evening. ...Discussion... Minimal adjustment was made to the previous convective outlook. ..Smith.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 10 2019/ ...Northwest... A closed mid-level low near the CA/OR coastal border will gradually evolve into an open wave while ejecting towards the OR/ID border through tonight, as other subtle speed maxima rotate around the eastern periphery of the low. A plume of weak to moderate buoyancy will develop at peak heating, arcing from OR/ID east across the northern Rockies and High Plains where scattered thunderstorms will likely form by late afternoon. Greatest effective shear should be centered across southern MT where weak low-level easterlies will be present beneath southwesterlies aloft that strengthen with height. This should yield an elongated, straight-line hodograph favorable for several splitting supercell structures. Large hail and severe wind gusts will be the primary hazards. Relatively high LCLs may limit the overall tornado threat, but brief ones are possible where 50s surface dew points can be sustained. ...Eastern NC... Sea breeze circulations along with a weakly convergent quasi-stationary front should be the focus for isolated to perhaps scattered thunderstorm development during the next few hours. Rich boundary-layer moisture characterized by low to mid 70s surface dew points exists over coastal southern NC into SC which will result in a confined corridor of MLCAPE in excess of 2000 J/kg. A few cells should briefly organize amid 30-40 kt 500-mb west-northwesterlies. Isolated large hail and damaging winds are anticipated. A marginal severe threat may persist into tonight amid weak low-level warm advection. ...Central High Plains to IA vicinity... A messy/low confidence scenario is anticipated through tonight with multiple MCVs and lingering cloud debris across the region. Forcing for ascent will likely persist across the Mid-MO Valley in a zone of low-level warm advection. Pockets of greater surface heating are apparent within cloud breaks into IA which combined with low-level moistening should support weak to moderate MLCAPE. Moderate enlargement/curvature to the low-level hodograph may foster a conditional brief tornado/locally damaging wind risk. Relatively warm profiles aloft and weak mid-level lapse rates will be unfavorable for large hail. Otherwise, scattered late afternoon storms should develop off the southern Rockies across eastern CO. Modest effective shear may be adequate to support multicell clustering as convection impinges on substantially greater buoyancy across KS/NE. Low-level warm advection will also increase across KS tonight in response to a nocturnal low-level jet, when more widespread convection is expected in the form of multiple clusters. Given the shear profiles, convection may be only weakly organized and slow-moving. But a threat for locally severe wind gusts should exist given heavy precipitation loading amid PW in excess of 2 inches. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0235 PM CDT Sat Aug 10 2019 Valid 102000Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF ID/MT/WY AND EASTERN NC... ...SUMMARY... Scattered severe thunderstorms with large hail and damaging wind gusts are most likely across parts of Idaho, Montana, Wyoming, and eastern North Carolina. The severe threat should be greatest during the late afternoon to early evening. ...Discussion... Minimal adjustment was made to the previous convective outlook. ..Smith.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 10 2019/ ...Northwest... A closed mid-level low near the CA/OR coastal border will gradually evolve into an open wave while ejecting towards the OR/ID border through tonight, as other subtle speed maxima rotate around the eastern periphery of the low. A plume of weak to moderate buoyancy will develop at peak heating, arcing from OR/ID east across the northern Rockies and High Plains where scattered thunderstorms will likely form by late afternoon. Greatest effective shear should be centered across southern MT where weak low-level easterlies will be present beneath southwesterlies aloft that strengthen with height. This should yield an elongated, straight-line hodograph favorable for several splitting supercell structures. Large hail and severe wind gusts will be the primary hazards. Relatively high LCLs may limit the overall tornado threat, but brief ones are possible where 50s surface dew points can be sustained. ...Eastern NC... Sea breeze circulations along with a weakly convergent quasi-stationary front should be the focus for isolated to perhaps scattered thunderstorm development during the next few hours. Rich boundary-layer moisture characterized by low to mid 70s surface dew points exists over coastal southern NC into SC which will result in a confined corridor of MLCAPE in excess of 2000 J/kg. A few cells should briefly organize amid 30-40 kt 500-mb west-northwesterlies. Isolated large hail and damaging winds are anticipated. A marginal severe threat may persist into tonight amid weak low-level warm advection. ...Central High Plains to IA vicinity... A messy/low confidence scenario is anticipated through tonight with multiple MCVs and lingering cloud debris across the region. Forcing for ascent will likely persist across the Mid-MO Valley in a zone of low-level warm advection. Pockets of greater surface heating are apparent within cloud breaks into IA which combined with low-level moistening should support weak to moderate MLCAPE. Moderate enlargement/curvature to the low-level hodograph may foster a conditional brief tornado/locally damaging wind risk. Relatively warm profiles aloft and weak mid-level lapse rates will be unfavorable for large hail. Otherwise, scattered late afternoon storms should develop off the southern Rockies across eastern CO. Modest effective shear may be adequate to support multicell clustering as convection impinges on substantially greater buoyancy across KS/NE. Low-level warm advection will also increase across KS tonight in response to a nocturnal low-level jet, when more widespread convection is expected in the form of multiple clusters. Given the shear profiles, convection may be only weakly organized and slow-moving. But a threat for locally severe wind gusts should exist given heavy precipitation loading amid PW in excess of 2 inches. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0235 PM CDT Sat Aug 10 2019 Valid 102000Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF ID/MT/WY AND EASTERN NC... ...SUMMARY... Scattered severe thunderstorms with large hail and damaging wind gusts are most likely across parts of Idaho, Montana, Wyoming, and eastern North Carolina. The severe threat should be greatest during the late afternoon to early evening. ...Discussion... Minimal adjustment was made to the previous convective outlook. ..Smith.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 10 2019/ ...Northwest... A closed mid-level low near the CA/OR coastal border will gradually evolve into an open wave while ejecting towards the OR/ID border through tonight, as other subtle speed maxima rotate around the eastern periphery of the low. A plume of weak to moderate buoyancy will develop at peak heating, arcing from OR/ID east across the northern Rockies and High Plains where scattered thunderstorms will likely form by late afternoon. Greatest effective shear should be centered across southern MT where weak low-level easterlies will be present beneath southwesterlies aloft that strengthen with height. This should yield an elongated, straight-line hodograph favorable for several splitting supercell structures. Large hail and severe wind gusts will be the primary hazards. Relatively high LCLs may limit the overall tornado threat, but brief ones are possible where 50s surface dew points can be sustained. ...Eastern NC... Sea breeze circulations along with a weakly convergent quasi-stationary front should be the focus for isolated to perhaps scattered thunderstorm development during the next few hours. Rich boundary-layer moisture characterized by low to mid 70s surface dew points exists over coastal southern NC into SC which will result in a confined corridor of MLCAPE in excess of 2000 J/kg. A few cells should briefly organize amid 30-40 kt 500-mb west-northwesterlies. Isolated large hail and damaging winds are anticipated. A marginal severe threat may persist into tonight amid weak low-level warm advection. ...Central High Plains to IA vicinity... A messy/low confidence scenario is anticipated through tonight with multiple MCVs and lingering cloud debris across the region. Forcing for ascent will likely persist across the Mid-MO Valley in a zone of low-level warm advection. Pockets of greater surface heating are apparent within cloud breaks into IA which combined with low-level moistening should support weak to moderate MLCAPE. Moderate enlargement/curvature to the low-level hodograph may foster a conditional brief tornado/locally damaging wind risk. Relatively warm profiles aloft and weak mid-level lapse rates will be unfavorable for large hail. Otherwise, scattered late afternoon storms should develop off the southern Rockies across eastern CO. Modest effective shear may be adequate to support multicell clustering as convection impinges on substantially greater buoyancy across KS/NE. Low-level warm advection will also increase across KS tonight in response to a nocturnal low-level jet, when more widespread convection is expected in the form of multiple clusters. Given the shear profiles, convection may be only weakly organized and slow-moving. But a threat for locally severe wind gusts should exist given heavy precipitation loading amid PW in excess of 2 inches. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0235 PM CDT Sat Aug 10 2019 Valid 102000Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF ID/MT/WY AND EASTERN NC... ...SUMMARY... Scattered severe thunderstorms with large hail and damaging wind gusts are most likely across parts of Idaho, Montana, Wyoming, and eastern North Carolina. The severe threat should be greatest during the late afternoon to early evening. ...Discussion... Minimal adjustment was made to the previous convective outlook. ..Smith.. 08/10/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 10 2019/ ...Northwest... A closed mid-level low near the CA/OR coastal border will gradually evolve into an open wave while ejecting towards the OR/ID border through tonight, as other subtle speed maxima rotate around the eastern periphery of the low. A plume of weak to moderate buoyancy will develop at peak heating, arcing from OR/ID east across the northern Rockies and High Plains where scattered thunderstorms will likely form by late afternoon. Greatest effective shear should be centered across southern MT where weak low-level easterlies will be present beneath southwesterlies aloft that strengthen with height. This should yield an elongated, straight-line hodograph favorable for several splitting supercell structures. Large hail and severe wind gusts will be the primary hazards. Relatively high LCLs may limit the overall tornado threat, but brief ones are possible where 50s surface dew points can be sustained. ...Eastern NC... Sea breeze circulations along with a weakly convergent quasi-stationary front should be the focus for isolated to perhaps scattered thunderstorm development during the next few hours. Rich boundary-layer moisture characterized by low to mid 70s surface dew points exists over coastal southern NC into SC which will result in a confined corridor of MLCAPE in excess of 2000 J/kg. A few cells should briefly organize amid 30-40 kt 500-mb west-northwesterlies. Isolated large hail and damaging winds are anticipated. A marginal severe threat may persist into tonight amid weak low-level warm advection. ...Central High Plains to IA vicinity... A messy/low confidence scenario is anticipated through tonight with multiple MCVs and lingering cloud debris across the region. Forcing for ascent will likely persist across the Mid-MO Valley in a zone of low-level warm advection. Pockets of greater surface heating are apparent within cloud breaks into IA which combined with low-level moistening should support weak to moderate MLCAPE. Moderate enlargement/curvature to the low-level hodograph may foster a conditional brief tornado/locally damaging wind risk. Relatively warm profiles aloft and weak mid-level lapse rates will be unfavorable for large hail. Otherwise, scattered late afternoon storms should develop off the southern Rockies across eastern CO. Modest effective shear may be adequate to support multicell clustering as convection impinges on substantially greater buoyancy across KS/NE. Low-level warm advection will also increase across KS tonight in response to a nocturnal low-level jet, when more widespread convection is expected in the form of multiple clusters. Given the shear profiles, convection may be only weakly organized and slow-moving. But a threat for locally severe wind gusts should exist given heavy precipitation loading amid PW in excess of 2 inches. Read more

WW 0567 Status Updates
STATUS FOR WATCH 0567 HAS NOT BEEN ISSUED YET Read more

WW 0567 Status Updates
STATUS FOR WATCH 0567 HAS NOT BEEN ISSUED YET Read more

MD 1689 CONCERNING SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY FOR PORTIONS OF SOUTHERN MT INTO NORTHERN WY
Mesoscale Discussion 1689 NWS Storm Prediction Center Norman OK 0144 PM CDT Sat Aug 10 2019 Areas affected...portions of southern MT into northern WY Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 101844Z - 102015Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms are expected to develop over the higher terrain of southern MT and northern WY in the next couple of hours. These storms will pose a threat for large hail and locally damaging gusts. DISCUSSION...Strong heating across southern MT into WY is resulting in a rapidly destabilizing airmass early this afternoon, especially in the I-90 corridor from LVM to BIL to GCC. CU have been increasing along the higher terrain of the Beartooth-Absaroka ranges as well as along the Big Horns. Some weak inhibition remains across the region per 18z mesoanalysis, and is likely suppressing the full potential of a storm near the southern end of the Big Horns over Johnson County WY. Most recently, this storm has produced hail a half an inch in diameter. Remaining inhibition should quickly erode over the next couple of hours with additional heating and as forcing for ascent increases modestly. Midlevel lapse rates are a bit more modest across this area than points further west where mid/upper level temperatures are cooler, but still favorable for large hail potential in the presence of 35+ kt effective shear. Thunderstorms should first develop along higher terrain and track east/northeast across the High Plains into early evening. Discrete cells or storm clusters with rotating updrafts will be capable of severe hail. Additionally, high-based storms with steep low-level lapse rates and inverted-v sub-cloud layer thermodynamic profiles will support locally damaging winds. How far northeast the threat may extend across eastern MT is somewhat uncertain. A weak cold front moved across parts of eastern MT and western ND this morning. The airmass across this area should remain capped and under the influence of at least weak subsidence, with the greater severe threat likely remaining south of I-94 across southeast MT. A severe thunderstorm watch will likely be needed for portions of the MCD area by 20z or 21z. ..Leitman/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...UNR...BYZ...RIW...TFX... LAT...LON 46521025 46740922 46640727 46260595 45780482 45180420 44570407 44060428 43810469 43680546 43660621 44120838 44380941 44671033 44871072 45671075 46521025 Read more

MD 1688 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHERN CA...SOUTH-CENTRAL/SOUTHWEST OR
Mesoscale Discussion 1688 NWS Storm Prediction Center Norman OK 0136 PM CDT Sat Aug 10 2019 Areas affected...Northern CA...South-central/southwest OR Concerning...Severe potential...Watch unlikely Valid 101836Z - 102030Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe thunderstorms are possible into this afternoon, with the primary threats being locally severe wind gusts and marginally severe hail. Watch issuance is unlikely. DISCUSSION...At 1830Z, a longer-lived thunderstorm cluster is moving across far northeast CA, while other convection is beginning to develop across a larger portion of northern CA, in the vicinity of a seasonably strong mid/upper-level low. Despite widespread cloudiness and generally limited heating, cool temperatures aloft are supporting SBCAPE of 500-1250 J/kg across this region, per recent mesoanalyses. Deep-layer shear is rather limited in the immediate vicinity of the mid/upper low across north-central CA into southwest OR, but somewhat stronger within a belt of southerly midlevel flow to the east across northeast CA into south-central OR. Generally cool temperatures aloft and steep midlevel lapse rates will support some potential for marginally severe hail across the region into this afternoon. Where effective shear is stronger across the northeast CA into south-central OR, a somewhat greater risk for hail with more organized storm structures will be present, in addition to the threat for isolated severe wind gusts. In general, the severe threat is expected to remain too limited in coverage and magnitude for watch issuance. ..Dean/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PDT...REV...MFR...STO...PQR...EKA... LAT...LON 39992118 40062318 41352323 42662293 43542246 43812192 43902115 43732058 42962008 41301989 40932002 39992118 Read more

No watches are valid as of Sat Aug 10 18:01:02 UTC 2019.

MD 1687 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN NC AND ADJACENT PORTIONS OF UPSTATE SC AND SOUTHWEST VA
Mesoscale Discussion 1687 NWS Storm Prediction Center Norman OK 1259 PM CDT Sat Aug 10 2019 Areas affected...Western NC and adjacent portions of Upstate SC and southwest VA Concerning...Severe potential...Watch unlikely Valid 101759Z - 102000Z Probability of Watch Issuance...5 percent SUMMARY...A few strong thunderstorms are possible this afternoon, with the strongest cells capable of locally damaging wind and perhaps marginally severe hail. Watch issuance is not anticipated. DISCUSSION...Convection has been gradually increasing in coverage early this afternoon across the higher terrain of western NC and adjacent Upstate SC and southwest VA. Modest heating of a moist environment has resulted in the development of MLCAPE in the 500-1000 J/kg range, while moderate mid/upper-level flow on the periphery of a deep upper trough to the north is supporting effective shear of 30-40 kt across the region. This environment will support some potential for updraft organization, with the strongest cells capable of producing locally damaging wind and perhaps marginally severe hail. While a few marginally severe storms are possible this afternoon, the overall threat is expected to remain too marginal for watch issuance. ..Dean/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...RAH...RNK...CAE...GSP...MRX... LAT...LON 35268277 35768242 36528153 37228102 37288024 37077963 36297963 35677976 35178025 34938065 34838096 34768167 34988274 35268277 Read more

MD 1686 CONCERNING SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY FOR PORTIONS OF EASTERN OR...FAR SOUTHEAST WA...SOUTHWEST AND CENTRAL ID AND WESTERN MT
Mesoscale Discussion 1686 NWS Storm Prediction Center Norman OK 1241 PM CDT Sat Aug 10 2019 Areas affected...portions of eastern OR...far southeast WA...southwest and central ID and western MT Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 101741Z - 101945Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms will increase in coverage and intensity from far eastern OR into central ID and western MT over the next couple of hours. Large hail and damaging winds will be the main threats with these storms and a watch will likely be needed. DISCUSSION...Forcing for ascent is increasing across the northern Rockies late this morning, per increasing thunderstorm activity near the OR/ID border and more recently across central ID. Strong heating to the north and east of this activity is resulting in a quickly destabilizing airmass characterized by unusually high dewpoints, ranging from the low to mid 50s F mostly, but several areas are approaching 60F. As a result, MLCAPE increasing to around 1500 J/kg is expected in a swath from central ID into western MT by early afternoon. This should result in vigorous thunderstorm development over the next couple of hours over higher terrain. Effective shear greater than 35 kt will allow cells to quickly become organized with rotating updrafts and possibly some supercell structures. Midlevel lapse rates are very steep, as evident in 12z regional RAOBs. Combined with favorable vertical shear profiles, large hail will be possible. Furthermore, storms will likely be high-based as boundary layer moisture mixes out with increased heating. Steepening low level lapse rates will result and fast storm motion will aid in strong wind gust potential as well. Where higher dewpoints are maintained, forecast guidance suggests there could be a brief, conditional tornado threat, mainly over parts of western MT where east/southeasterly low level flow will enhanced effective SRH. However, this threat is more uncertain than the expected large hail and strong, locally damaging gusts. The severe threat will continue to increase over the next couple of hours as additional heating reduces inhibition and forcing for ascent continues to increase. A severe thunderstorms watch will likely be needed by 19 or 20z. ..Leitman/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TFX...PIH...MSO...BOI...OTX...PDT... LAT...LON 45411096 44971189 44531336 44011425 43211496 42591549 42261634 42171700 42421794 43091864 44141957 44701987 45251985 45931919 46631814 47021743 47471571 47751386 47711302 47411188 46831112 45861101 45411096 Read more

MD 1685 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHEAST NC...NORTHEAST SC
Mesoscale Discussion 1685 NWS Storm Prediction Center Norman OK 1237 PM CDT Sat Aug 10 2019 Areas affected...Southeast NC...Northeast SC Concerning...Severe potential...Watch unlikely Valid 101737Z - 101930Z Probability of Watch Issuance...20 percent SUMMARY...A few thunderstorms capable of locally damaging winds and perhaps some hail are possible this afternoon. Watch issuance is currently considered unlikely due to the limited areal extent of the threat. DISCUSSION...As of 1730Z, cumulus is increasing along a weak surface boundary across southeast NC, and also along the sea breeze from coastal portions of northeast SC into southeast NC. Temperatures rising into the low 90s F combined with rich low-level moisture are resulting in the development of moderate buoyancy, with MLCAPE already in the 1000-1500 J/kg range (per recent mesoanalyses) and some further increase possible this afternoon. Meanwhile, moderate mid/upper-level flow on the periphery of a deep upper trough over the Northeast is resulting in effective shear of 25-35 kt across the region. This shear will be sufficient to support some updraft organization with any deep convection that develops this afternoon. Locally damaging wind will be a threat given the potential for water-loading within a very moist environment, while any well-organized multicell or supercell structures that develop will have some hail potential, despite relatively warm temperatures aloft. The areal extent of the primary threat is expected to remain confined to near the coast, and the number of storms within the threat area remains uncertain given generally limited large-scale ascent across the region. Given these factors, watch issuance is considered unlikely, though a conditional severe threat will be present with any storms this afternoon. ..Dean/Grams.. 08/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MHX...RAH...ILM...CHS... LAT...LON 33777808 33407864 32887915 32827977 33147970 33917917 35067849 35167796 35237724 35227676 35097640 34887622 34777647 34667654 34457699 34177744 33777808 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1234 PM CDT Sat Aug 10 2019 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHWEST NEBRASKA... ...SUMMARY... Areas of strong to severe storms are expected over portions of the northern through central High Plains Sunday afternoon into Sunday night. Large hail and severe gusts are the primary threats. ...Synopsis... Upper trough now approaching northern CA will transition to an open wave and continue through the northern Rockies and northern High Plains Sunday and Sunday night, flattening the northern periphery of an upper ridge centered over the southern Plains. A mid-level disturbance of convective origin was analyzed over far southeast AZ midday Saturday. The disturbance is forecast to move north and northeastward across western NM/CO before reaching northeast CO by early evening Sunday. Sunday morning a cold front will extend from northern MN southwest into northeast WY. The western extension of this boundary will stall before moving north as a warm front through eastern MT. A secondary front will extend from a weak surface low in IA westward through southern NE. The western extension of this boundary will stall near the KS/NE border. ...Central High Plains region... Early-day storms are forecast over KS/NE into the lower MO Valley within zone of isentropic ascent. This activity is expected to diminish as it moves east-southeastward during the day. In wake of morning storms, rich low-level moisture with mid-upper 60s F dewpoints and diabatic warming will support a corridor of moderate to strong instability (2000-2500 J/kg MLCAPE) in vicinity of the stalled front over northern KS/southern NE. Easterly upslope flow will exist north of this boundary, and storms are expected to develop over the higher terrain in association with the central Rockies impulse, as well as near the front/lee trough intersection during the late afternoon and spread east during the evening. A belt of moderate (30-35 kt) southwesterly mid-level winds will overspread the central High Plains from northeast CO into southwest NE. Some supercells are possible early over CO before outflow becomes more pervasive and storms grow upscale into clusters/lines as they develop east towards the KS/NE/CO border before spreading east overnight. Severe gusts will be the primary hazard once storms grow upscale. ...Northern Rockies through northern High Plains... Moist axis will be shunted southwestward by the south-advancing cold front, before retreating back north as a warm front through eastern MT. The corridor of modest low-level moisture with upper 50s F dewpoints beneath steep mid-level lapse rates will support moderate instability (1500-2000 J/kg from central MT through northeast WY and possibly southwest SD) as the surface layer warms during the afternoon. Storms are expected to develop over the higher terrain and spread northeast through the relatively narrow instability corridor during the afternoon and early evening. A belt of stronger winds aloft accompanying the upper trough will support 40-45 kt effective bulk shear supportive of organized storms. Large hail and severe gusts associated with high-based supercells will likely transition into outflow-efficient clusters capable of severe gusts. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 30% - Enhanced Hail: 15% - Slight ..Smith.. 08/10/2019 Read more