Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Sep 08 2019 Valid 081200Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEASTERN UTAH... ...Synopsis... A mid-level shortwave trough -- embedded near the base of a longer wavelength mid/upper-level trough located over much of the western CONUS -- is forecast to move from the Great Basin into the central/northern Rockies today/tonight. ...Southwest into the southern Great Basin... An area of enhanced mid-level flow, associated with the aforementioned shortwave trough, is forecast to overspread portions of southern Nevada/Utah and northern Arizona this afternoon and evening. Relatively steep low-level lapse rates should allow for efficient downward mixing of these stronger winds from aloft, with sustained winds of 15-25 mph amidst near critical RH values (e.g., around 15%). Critical conditions still appear most probable across southeast Utah, where the timing of the enhanced flow aloft best coincides with peak heating and minimum RH reductions. While near-critical conditions are possible outside of the critical fire weather area -- mainly across west/southwest Utah and northern Arizona -- uncertainty regarding the extent/duration of critical conditions in these areas precludes a critical designation at this time. ...Southern California... Elevated to locally critical conditions are forecast to be ongoing -- mainly at elevations > 1 kft -- this morning from Santa Barbara County southward toward the San Diego County mountains due to poor overnight RH recoveries and gusty surface winds (locally 40+ mph). Surface winds should generally weaken and become less gusty this morning and early afternoon, before increasing again by mid-afternoon with elevated fire weather conditions redeveloping (especially over Santa Barbara, eastern Ventura, and western Los Angeles Counties). Poor overnight RH recoveries and lingering gusty winds may allow elevated fire weather conditions to persist through the overnight. ..Elliott.. 09/08/2019 ...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 1252 AM CDT Sun Sep 08 2019 Valid 081200Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEASTERN UTAH... ...Synopsis... A mid-level shortwave trough -- embedded near the base of a longer wavelength mid/upper-level trough located over much of the western CONUS -- is forecast to move from the Great Basin into the central/northern Rockies today/tonight. ...Southwest into the southern Great Basin... An area of enhanced mid-level flow, associated with the aforementioned shortwave trough, is forecast to overspread portions of southern Nevada/Utah and northern Arizona this afternoon and evening. Relatively steep low-level lapse rates should allow for efficient downward mixing of these stronger winds from aloft, with sustained winds of 15-25 mph amidst near critical RH values (e.g., around 15%). Critical conditions still appear most probable across southeast Utah, where the timing of the enhanced flow aloft best coincides with peak heating and minimum RH reductions. While near-critical conditions are possible outside of the critical fire weather area -- mainly across west/southwest Utah and northern Arizona -- uncertainty regarding the extent/duration of critical conditions in these areas precludes a critical designation at this time. ...Southern California... Elevated to locally critical conditions are forecast to be ongoing -- mainly at elevations > 1 kft -- this morning from Santa Barbara County southward toward the San Diego County mountains due to poor overnight RH recoveries and gusty surface winds (locally 40+ mph). Surface winds should generally weaken and become less gusty this morning and early afternoon, before increasing again by mid-afternoon with elevated fire weather conditions redeveloping (especially over Santa Barbara, eastern Ventura, and western Los Angeles Counties). Poor overnight RH recoveries and lingering gusty winds may allow elevated fire weather conditions to persist through the overnight. ..Elliott.. 09/08/2019 ...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 1252 AM CDT Sun Sep 08 2019 Valid 081200Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEASTERN UTAH... ...Synopsis... A mid-level shortwave trough -- embedded near the base of a longer wavelength mid/upper-level trough located over much of the western CONUS -- is forecast to move from the Great Basin into the central/northern Rockies today/tonight. ...Southwest into the southern Great Basin... An area of enhanced mid-level flow, associated with the aforementioned shortwave trough, is forecast to overspread portions of southern Nevada/Utah and northern Arizona this afternoon and evening. Relatively steep low-level lapse rates should allow for efficient downward mixing of these stronger winds from aloft, with sustained winds of 15-25 mph amidst near critical RH values (e.g., around 15%). Critical conditions still appear most probable across southeast Utah, where the timing of the enhanced flow aloft best coincides with peak heating and minimum RH reductions. While near-critical conditions are possible outside of the critical fire weather area -- mainly across west/southwest Utah and northern Arizona -- uncertainty regarding the extent/duration of critical conditions in these areas precludes a critical designation at this time. ...Southern California... Elevated to locally critical conditions are forecast to be ongoing -- mainly at elevations > 1 kft -- this morning from Santa Barbara County southward toward the San Diego County mountains due to poor overnight RH recoveries and gusty surface winds (locally 40+ mph). Surface winds should generally weaken and become less gusty this morning and early afternoon, before increasing again by mid-afternoon with elevated fire weather conditions redeveloping (especially over Santa Barbara, eastern Ventura, and western Los Angeles Counties). Poor overnight RH recoveries and lingering gusty winds may allow elevated fire weather conditions to persist through the overnight. ..Elliott.. 09/08/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Sep 08 2019 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms associated with hail and marginally severe wind gusts will be possible on Monday across parts of the central and northern Plains eastward into the upper Mississippi Valley. ...Central and Northern Plains/Upper Mississippi Valley... A shortwave ridge will move into the Great Lakes region on Monday as a shortwave trough moves across the Northern Plains. At the surface, a low is forecast to deepen across South Dakota as a warm front advances northeastward into the upper Mississippi Valley. Elevated thunderstorms will be possible to the north of the warm front across parts of Minnesota and Wisconsin during the day. A corridor of maximized low-level moisture (dewpoints of 68 to 72 F) should be in place to the east of the surface low from eastern South Dakota southeastward into Iowa. This corridor will be the preferred area for surface-based convection during the afternoon. NAM forecast soundings along and just south of the warm front at 00Z/Tuesday show MLCAPE mostly in the 1500 to 2500 J/kg range. 0-6 km shear is forecast to be from 35 to 45 kt suggesting supercells will be possible. Supercells would be capable of large hail and wind damage. As the warm front moves northeastward, the strongest instability will translate quickly northeastward across the mid Missouri Valley. For this reason, the timing of the shortwave trough will be very important to the placement of the greatest severe threat. For this reason, a marginal risk area will suffice for this forecast until confidence increases concerning the finer-scale details of the scenario. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Broyles.. 09/08/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Sep 08 2019 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms associated with hail and marginally severe wind gusts will be possible on Monday across parts of the central and northern Plains eastward into the upper Mississippi Valley. ...Central and Northern Plains/Upper Mississippi Valley... A shortwave ridge will move into the Great Lakes region on Monday as a shortwave trough moves across the Northern Plains. At the surface, a low is forecast to deepen across South Dakota as a warm front advances northeastward into the upper Mississippi Valley. Elevated thunderstorms will be possible to the north of the warm front across parts of Minnesota and Wisconsin during the day. A corridor of maximized low-level moisture (dewpoints of 68 to 72 F) should be in place to the east of the surface low from eastern South Dakota southeastward into Iowa. This corridor will be the preferred area for surface-based convection during the afternoon. NAM forecast soundings along and just south of the warm front at 00Z/Tuesday show MLCAPE mostly in the 1500 to 2500 J/kg range. 0-6 km shear is forecast to be from 35 to 45 kt suggesting supercells will be possible. Supercells would be capable of large hail and wind damage. As the warm front moves northeastward, the strongest instability will translate quickly northeastward across the mid Missouri Valley. For this reason, the timing of the shortwave trough will be very important to the placement of the greatest severe threat. For this reason, a marginal risk area will suffice for this forecast until confidence increases concerning the finer-scale details of the scenario. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Broyles.. 09/08/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Sep 08 2019 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms associated with hail and marginally severe wind gusts will be possible on Monday across parts of the central and northern Plains eastward into the upper Mississippi Valley. ...Central and Northern Plains/Upper Mississippi Valley... A shortwave ridge will move into the Great Lakes region on Monday as a shortwave trough moves across the Northern Plains. At the surface, a low is forecast to deepen across South Dakota as a warm front advances northeastward into the upper Mississippi Valley. Elevated thunderstorms will be possible to the north of the warm front across parts of Minnesota and Wisconsin during the day. A corridor of maximized low-level moisture (dewpoints of 68 to 72 F) should be in place to the east of the surface low from eastern South Dakota southeastward into Iowa. This corridor will be the preferred area for surface-based convection during the afternoon. NAM forecast soundings along and just south of the warm front at 00Z/Tuesday show MLCAPE mostly in the 1500 to 2500 J/kg range. 0-6 km shear is forecast to be from 35 to 45 kt suggesting supercells will be possible. Supercells would be capable of large hail and wind damage. As the warm front moves northeastward, the strongest instability will translate quickly northeastward across the mid Missouri Valley. For this reason, the timing of the shortwave trough will be very important to the placement of the greatest severe threat. For this reason, a marginal risk area will suffice for this forecast until confidence increases concerning the finer-scale details of the scenario. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Broyles.. 09/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CDT Sun Sep 08 2019 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTERED OVER THE CENTRAL HIGH PLAINS REGION... ...SUMMARY... Isolated severe thunderstorms with strong/gusty winds and hail will be possible across parts of the central Rockies and adjacent High Plains Sunday afternoon and evening. ...Synopsis... Cyclonic flow aloft will diminish over the northeastern U.S., as a low shifts northeastward across the Canadian Maritimes. In the West, a lead trough is forecast to shift east across the Intermountain West, eventually reaching the high Plains, ahead of a larger trough/low expected to move gradually onshore over the West Coast. In between the western and northeastern troughing, low-amplitude ridging will cross the central U.S. through the period. At the surface, a weak baroclinic zone will lie east to west across Missouri and Kansas, and then northwestward along the high Plains. As the upper system advances across the Rockies, a weak/elongated frontal low is forecast to gradually develop, centered over the northeastern Wyoming vicinity. ...Central High Plains vicinity... As the upper trough crosses the West, showers and thunderstorms are forecast to increase in coverage through the day across a broad portion of the Intermountain region. As increasing ascent begins reaching the high Plains during the afternoon, where low-level southeasterly flow is expected to maintain a slightly more moist low-level airmass, the more favorable instability will support an increase in storm coverage and intensity. The approach of the upper system will also bring a modest increase in flow aloft, likely supporting a progression of convection off the higher terrain and across the central high Plains -- possibly evolving into a semi-organized band or bands into the evening hours. This evolution will correspond with some potential for gusty/locally damaging winds, and possibly marginal hail through the evening hours. ..Goss/Elliott.. 09/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CDT Sun Sep 08 2019 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTERED OVER THE CENTRAL HIGH PLAINS REGION... ...SUMMARY... Isolated severe thunderstorms with strong/gusty winds and hail will be possible across parts of the central Rockies and adjacent High Plains Sunday afternoon and evening. ...Synopsis... Cyclonic flow aloft will diminish over the northeastern U.S., as a low shifts northeastward across the Canadian Maritimes. In the West, a lead trough is forecast to shift east across the Intermountain West, eventually reaching the high Plains, ahead of a larger trough/low expected to move gradually onshore over the West Coast. In between the western and northeastern troughing, low-amplitude ridging will cross the central U.S. through the period. At the surface, a weak baroclinic zone will lie east to west across Missouri and Kansas, and then northwestward along the high Plains. As the upper system advances across the Rockies, a weak/elongated frontal low is forecast to gradually develop, centered over the northeastern Wyoming vicinity. ...Central High Plains vicinity... As the upper trough crosses the West, showers and thunderstorms are forecast to increase in coverage through the day across a broad portion of the Intermountain region. As increasing ascent begins reaching the high Plains during the afternoon, where low-level southeasterly flow is expected to maintain a slightly more moist low-level airmass, the more favorable instability will support an increase in storm coverage and intensity. The approach of the upper system will also bring a modest increase in flow aloft, likely supporting a progression of convection off the higher terrain and across the central high Plains -- possibly evolving into a semi-organized band or bands into the evening hours. This evolution will correspond with some potential for gusty/locally damaging winds, and possibly marginal hail through the evening hours. ..Goss/Elliott.. 09/08/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CDT Sun Sep 08 2019 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTERED OVER THE CENTRAL HIGH PLAINS REGION... ...SUMMARY... Isolated severe thunderstorms with strong/gusty winds and hail will be possible across parts of the central Rockies and adjacent High Plains Sunday afternoon and evening. ...Synopsis... Cyclonic flow aloft will diminish over the northeastern U.S., as a low shifts northeastward across the Canadian Maritimes. In the West, a lead trough is forecast to shift east across the Intermountain West, eventually reaching the high Plains, ahead of a larger trough/low expected to move gradually onshore over the West Coast. In between the western and northeastern troughing, low-amplitude ridging will cross the central U.S. through the period. At the surface, a weak baroclinic zone will lie east to west across Missouri and Kansas, and then northwestward along the high Plains. As the upper system advances across the Rockies, a weak/elongated frontal low is forecast to gradually develop, centered over the northeastern Wyoming vicinity. ...Central High Plains vicinity... As the upper trough crosses the West, showers and thunderstorms are forecast to increase in coverage through the day across a broad portion of the Intermountain region. As increasing ascent begins reaching the high Plains during the afternoon, where low-level southeasterly flow is expected to maintain a slightly more moist low-level airmass, the more favorable instability will support an increase in storm coverage and intensity. The approach of the upper system will also bring a modest increase in flow aloft, likely supporting a progression of convection off the higher terrain and across the central high Plains -- possibly evolving into a semi-organized band or bands into the evening hours. This evolution will correspond with some potential for gusty/locally damaging winds, and possibly marginal hail through the evening hours. ..Goss/Elliott.. 09/08/2019 Read more

MD 1938 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF NORTH CENTRAL/NORTHEAST KANSAS AND ADJACENT PORTIONS OF SOUTHERN NEBRASKA
Mesoscale Discussion 1938 NWS Storm Prediction Center Norman OK 0846 PM CDT Sat Sep 07 2019 Areas affected...Parts of north central/northeast Kansas and adjacent portions of southern Nebraska Concerning...Severe potential...Watch unlikely Valid 080146Z - 080245Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorm activity will continue to increase across the region through 10 PM-Midnight CDT. This probably will pose a risk for occasional severe hail, and perhaps increasing potential for strong surface gusts later this evening. It still appears only a low probability that a severe weather watch will be needed, but trends will continue to be monitored. DISCUSSION...Boundary-layer based thunderstorm development, which has been spreading eastward along the axis of strongest daytime heating, into and through central Kansas, seems likely to diminish shortly. But new thunderstorm activity is in the process of developing to the north and northeast, rooted within a zone of enhanced low-level warm advection, along a frontal zone now focused roughly near the central/eastern Kansas and Nebraska state border area. Seasonably moist low-level air (including surface dew points in the lower/mid 70s F) has been maintained along the front across this region, and appears to be contributing to large CAPE on the order of 2000-4000 J/kg, in the presence of relatively steep lapse rates. Perhaps aided by modest southwesterly low-level jet strengthening (25-30+ kt at 850 mb), a substantive further increase in thunderstorms appears possible along the front through the 03-06Z time frame. Near the southern fringe of a belt of 30-40+ kt westerly flow around 500 mb, there appears at least some potential for upscale growing convection to organize and perhaps pose increasing potential for strong surface gusts. Otherwise, stronger storms developing through late evening may become capable of producing occasional severe hail. ..Kerr/Thompson.. 09/08/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...OAX...TOP...ICT...GID... LAT...LON 39869868 40379813 40569644 40049529 39179542 39179627 39209765 39159823 39529867 39869868 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Sep 07 2019 Valid 080100Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS THE PACIFIC NORTHWEST...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... A few storms capable of producing hail and damaging winds are expected this evening over parts of the mid Missouri Valley area, and near the northern Cascades. ...Pacific Northwest... Isolated thunderstorms have developed early this evening over the higher terrain of the Cascades, where modest instability and ample shear continue to suggest potential for organized updrafts. A couple of the stronger cells will be capable of producing hail and/or damaging winds over the next few hours. For additional short-term information, please refer to SWOMCD #1937. ...Mid Missouri Valley region... Diurnal thunderstorms have diminished across Nebraska, while a weak cluster of convection still producing lightning continues advancing across central Kansas. As a low-level jet increases over the next few hours, warm-advection-driven ascent should result in new storm development near and north of the boundary -- which currently extends northwest to southeast across central and eastern Kansas and into west-central and southern Missouri. With a plume of amply steep mid-level lapse rates across the area contributing to moderate CAPE through the cloud-bearing layer, and modest westerly flow atop low-level southwesterlies, resulting deep-layer shear will support some potential for organized storms -- and possibly upscale growth into an eastward-moving MCS. Some risk for gusty/locally damaging winds will exist near the front, while hail will also be possible -- especially before an upscale convective evolution occurs. ..Goss.. 09/08/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Sep 07 2019 Valid 080100Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS THE PACIFIC NORTHWEST...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... A few storms capable of producing hail and damaging winds are expected this evening over parts of the mid Missouri Valley area, and near the northern Cascades. ...Pacific Northwest... Isolated thunderstorms have developed early this evening over the higher terrain of the Cascades, where modest instability and ample shear continue to suggest potential for organized updrafts. A couple of the stronger cells will be capable of producing hail and/or damaging winds over the next few hours. For additional short-term information, please refer to SWOMCD #1937. ...Mid Missouri Valley region... Diurnal thunderstorms have diminished across Nebraska, while a weak cluster of convection still producing lightning continues advancing across central Kansas. As a low-level jet increases over the next few hours, warm-advection-driven ascent should result in new storm development near and north of the boundary -- which currently extends northwest to southeast across central and eastern Kansas and into west-central and southern Missouri. With a plume of amply steep mid-level lapse rates across the area contributing to moderate CAPE through the cloud-bearing layer, and modest westerly flow atop low-level southwesterlies, resulting deep-layer shear will support some potential for organized storms -- and possibly upscale growth into an eastward-moving MCS. Some risk for gusty/locally damaging winds will exist near the front, while hail will also be possible -- especially before an upscale convective evolution occurs. ..Goss.. 09/08/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Sep 07 2019 Valid 080100Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS THE PACIFIC NORTHWEST...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... A few storms capable of producing hail and damaging winds are expected this evening over parts of the mid Missouri Valley area, and near the northern Cascades. ...Pacific Northwest... Isolated thunderstorms have developed early this evening over the higher terrain of the Cascades, where modest instability and ample shear continue to suggest potential for organized updrafts. A couple of the stronger cells will be capable of producing hail and/or damaging winds over the next few hours. For additional short-term information, please refer to SWOMCD #1937. ...Mid Missouri Valley region... Diurnal thunderstorms have diminished across Nebraska, while a weak cluster of convection still producing lightning continues advancing across central Kansas. As a low-level jet increases over the next few hours, warm-advection-driven ascent should result in new storm development near and north of the boundary -- which currently extends northwest to southeast across central and eastern Kansas and into west-central and southern Missouri. With a plume of amply steep mid-level lapse rates across the area contributing to moderate CAPE through the cloud-bearing layer, and modest westerly flow atop low-level southwesterlies, resulting deep-layer shear will support some potential for organized storms -- and possibly upscale growth into an eastward-moving MCS. Some risk for gusty/locally damaging winds will exist near the front, while hail will also be possible -- especially before an upscale convective evolution occurs. ..Goss.. 09/08/2019 Read more

MD 1937 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE OREGON AND WASHINGTON
Mesoscale Discussion 1937 NWS Storm Prediction Center Norman OK 0636 PM CDT Sat Sep 07 2019 Areas affected...Portions of the Oregon and Washington Concerning...Severe potential...Watch unlikely Valid 072336Z - 080200Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorms are forecast to increase in coverage into the overnight. The strongest storms may pose a marginal risk of isolated strong wind gusts and marginally severe hail. DISCUSSION...Radar, satellite, and lightning trends suggest thunderstorms are gradually increasing in coverage and intensity along/near the crest of the Cascades in Oregon and Washington. Thunderstorm activity is expected to remain mostly isolated to widely scattered over the next several hours, before coverage increases markedly overnight as ascent associated with a negatively tilted trough further impinges on the area. The environment across the area is currently characterized by MLCAPE of 500-1000 J/kg and effective bulk shear of 30-40 knots, which should promote semi-organized multicell thunderstorms (or transient supercell structures) that may be capable of producing isolated strong wind gusts and marginally severe hail over the next several hours. While thunderstorm coverage will increase overnight, intensity should decrease as boundary layer cooling ensues and buoyancy is reduced. A Severe Thunderstorm Watch is not currently expected due to the limited areal extent and the marginal nature of the threat. ..Elliott/Thompson.. 09/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OTX...PDT...SEW...PQR... LAT...LON 45222223 47332190 48712217 49102234 49142152 49152040 49151939 49131899 45801934 45161987 44652037 44292109 44392187 45222223 Read more

No watches are valid as of Sat Sep 7 23:41:06 UTC 2019.

MD 1937 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE OREGON AND WASHINGTON
Mesoscale Discussion 1937 NWS Storm Prediction Center Norman OK 0636 PM CDT Sat Sep 07 2019 Areas affected...Portions of the Oregon and Washington Concerning...Severe potential...Watch unlikely Valid 072336Z - 080200Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorms are forecast to increase in coverage into the overnight. The strongest storms may pose a marginal risk of isolated strong wind gusts and marginally severe hail. DISCUSSION...Radar, satellite, and lightning trends suggest thunderstorms are gradually increasing in coverage and intensity along/near the crest of the Cascades in Oregon and Washington. Thunderstorm activity is expected to remain mostly isolated to widely scattered over the next several hours, before coverage increases markedly overnight as ascent associated with a negatively tilted trough further impinges on the area. The environment across the area is currently characterized by MLCAPE of 500-1000 J/kg and effective bulk shear of 30-40 knots, which should promote semi-organized multicell thunderstorms (or transient supercell structures) that may be capable of producing isolated strong wind gusts and marginally severe hail over the next several hours. While thunderstorm coverage will increase overnight, intensity should decrease as boundary layer cooling ensues and buoyancy is reduced. A Severe Thunderstorm Watch is not currently expected due to the limited areal extent and the marginal nature of the threat. ..Elliott/Thompson.. 09/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OTX...PDT...SEW...PQR... LAT...LON 45222223 47332190 48712217 49102234 49142152 49152040 49151939 49131899 45801934 45161987 44652037 44292109 44392187 45222223 Read more

No Mesoscale Discussions are in effect as of Sat Sep 7 22:31:06 UTC 2019.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Sep 07 2019 Valid 072000Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS AND NORTHERN CASCADES... ...SUMMARY... Isolated severe wind and hail will remain possible today from thunderstorms over parts of the central Plains, and near the northern Cascades. ...20Z Update... No changes have been made to the Marginal Risk areas across the central Plains and Pacific Northwest. ..Gleason.. 09/07/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Sat Sep 07 2019/ ...Central Plains... A well-defined shortwave trough is moving quickly eastward today across eastern MT/WY. This feature will help to initiate scattered thunderstorm development this afternoon and evening from parts of eastern CO and western KS into portions of SD/NE/MO/IA. Low-level winds are forecast to be relatively weak across the central Plains, limiting overall convective organization. However, multiple remnant surface boundaries should be sufficient for a few clusters of multicell and occasional supercell storms through the evening. Forecast soundings suggest a risk of isolated strong/severe storms capable of gusty/damaging winds and hail. Given the weak low-level winds and expectation of rather disorganized convective, will maintain the ongoing MRGL risk with only minor changes. ...Pacific Northwest... A rather deep upper trough is approaching the OR/CA coast today. Strengthening wind fields and cooling aloft will aid initiation of scattered thunderstorms over central OR/WA along and east of the Cascades. Organized severe storms are not expected. However, the strongest cells could result in gusty winds and hail for a few hours this afternoon and evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Sep 07 2019 Valid 072000Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS AND NORTHERN CASCADES... ...SUMMARY... Isolated severe wind and hail will remain possible today from thunderstorms over parts of the central Plains, and near the northern Cascades. ...20Z Update... No changes have been made to the Marginal Risk areas across the central Plains and Pacific Northwest. ..Gleason.. 09/07/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Sat Sep 07 2019/ ...Central Plains... A well-defined shortwave trough is moving quickly eastward today across eastern MT/WY. This feature will help to initiate scattered thunderstorm development this afternoon and evening from parts of eastern CO and western KS into portions of SD/NE/MO/IA. Low-level winds are forecast to be relatively weak across the central Plains, limiting overall convective organization. However, multiple remnant surface boundaries should be sufficient for a few clusters of multicell and occasional supercell storms through the evening. Forecast soundings suggest a risk of isolated strong/severe storms capable of gusty/damaging winds and hail. Given the weak low-level winds and expectation of rather disorganized convective, will maintain the ongoing MRGL risk with only minor changes. ...Pacific Northwest... A rather deep upper trough is approaching the OR/CA coast today. Strengthening wind fields and cooling aloft will aid initiation of scattered thunderstorms over central OR/WA along and east of the Cascades. Organized severe storms are not expected. However, the strongest cells could result in gusty winds and hail for a few hours this afternoon and evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Sep 07 2019 Valid 072000Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS AND NORTHERN CASCADES... ...SUMMARY... Isolated severe wind and hail will remain possible today from thunderstorms over parts of the central Plains, and near the northern Cascades. ...20Z Update... No changes have been made to the Marginal Risk areas across the central Plains and Pacific Northwest. ..Gleason.. 09/07/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Sat Sep 07 2019/ ...Central Plains... A well-defined shortwave trough is moving quickly eastward today across eastern MT/WY. This feature will help to initiate scattered thunderstorm development this afternoon and evening from parts of eastern CO and western KS into portions of SD/NE/MO/IA. Low-level winds are forecast to be relatively weak across the central Plains, limiting overall convective organization. However, multiple remnant surface boundaries should be sufficient for a few clusters of multicell and occasional supercell storms through the evening. Forecast soundings suggest a risk of isolated strong/severe storms capable of gusty/damaging winds and hail. Given the weak low-level winds and expectation of rather disorganized convective, will maintain the ongoing MRGL risk with only minor changes. ...Pacific Northwest... A rather deep upper trough is approaching the OR/CA coast today. Strengthening wind fields and cooling aloft will aid initiation of scattered thunderstorms over central OR/WA along and east of the Cascades. Organized severe storms are not expected. However, the strongest cells could result in gusty winds and hail for a few hours this afternoon and evening. Read more