Aggregator

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 PM CDT Thu Aug 29 2019 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered storms, some producing severe wind gusts, are possible over southern Kansas into Oklahoma and the Texas Panhandle on Friday. Other storms capable of mainly hail are expected near the Front Range. ...Synopsis... A large-scale upper trough will move across eastern Canada with a trailing cold front moving across NY and New England. Ahead of this front, a narrow ribbon of dewpoints near 60 F may provide sufficient instability for isolated shallow thunderstorms. To the west, northwest flow aloft will remain over the central and northern Plains and Rockies, with neutral height tendencies. Within this regime, embedded disturbances associated with areas of ongoing storms will exist, mainly from KS into MO. A front will extend eastward from a weak low over the TX Panhandle to near the KS/OK border and into southern MO, providing a focus for additional storms. High pressure will nudge east across the upper MS Valley, maintaining an easterly surface wind component to the central High Plains where 50s F dewpoints support daytime storms. ...Central Plains... Numerous storms, possibly in the form of an MCS, may be ongoing over parts of eastern KS, western MO, and northeast OK Friday morning, with outflow boundaries likely determining precisely where afternoon and evening storms will regenerate. Ample moisture and instability will develop in precipitation-free areas, south of the stationary front and generally from the TX Panhandle eastward. Any outflow boundaries may provide a focus for further development, with localized damaging winds the primary concern. At this time, predictability is to low to focus higher severe probabilities. To the west, capping will exist for much of the day, but the western fringe of the 50s F dewpoints and stronger low-level lapse rates will likely support isolated development over the Front Range. Steep lapse rates aloft along with elongated mid to upper hodographs will favor hail before storms dissipate in the cooler air to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/29/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 PM CDT Thu Aug 29 2019 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered storms, some producing severe wind gusts, are possible over southern Kansas into Oklahoma and the Texas Panhandle on Friday. Other storms capable of mainly hail are expected near the Front Range. ...Synopsis... A large-scale upper trough will move across eastern Canada with a trailing cold front moving across NY and New England. Ahead of this front, a narrow ribbon of dewpoints near 60 F may provide sufficient instability for isolated shallow thunderstorms. To the west, northwest flow aloft will remain over the central and northern Plains and Rockies, with neutral height tendencies. Within this regime, embedded disturbances associated with areas of ongoing storms will exist, mainly from KS into MO. A front will extend eastward from a weak low over the TX Panhandle to near the KS/OK border and into southern MO, providing a focus for additional storms. High pressure will nudge east across the upper MS Valley, maintaining an easterly surface wind component to the central High Plains where 50s F dewpoints support daytime storms. ...Central Plains... Numerous storms, possibly in the form of an MCS, may be ongoing over parts of eastern KS, western MO, and northeast OK Friday morning, with outflow boundaries likely determining precisely where afternoon and evening storms will regenerate. Ample moisture and instability will develop in precipitation-free areas, south of the stationary front and generally from the TX Panhandle eastward. Any outflow boundaries may provide a focus for further development, with localized damaging winds the primary concern. At this time, predictability is to low to focus higher severe probabilities. To the west, capping will exist for much of the day, but the western fringe of the 50s F dewpoints and stronger low-level lapse rates will likely support isolated development over the Front Range. Steep lapse rates aloft along with elongated mid to upper hodographs will favor hail before storms dissipate in the cooler air to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/29/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 PM CDT Thu Aug 29 2019 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered storms, some producing severe wind gusts, are possible over southern Kansas into Oklahoma and the Texas Panhandle on Friday. Other storms capable of mainly hail are expected near the Front Range. ...Synopsis... A large-scale upper trough will move across eastern Canada with a trailing cold front moving across NY and New England. Ahead of this front, a narrow ribbon of dewpoints near 60 F may provide sufficient instability for isolated shallow thunderstorms. To the west, northwest flow aloft will remain over the central and northern Plains and Rockies, with neutral height tendencies. Within this regime, embedded disturbances associated with areas of ongoing storms will exist, mainly from KS into MO. A front will extend eastward from a weak low over the TX Panhandle to near the KS/OK border and into southern MO, providing a focus for additional storms. High pressure will nudge east across the upper MS Valley, maintaining an easterly surface wind component to the central High Plains where 50s F dewpoints support daytime storms. ...Central Plains... Numerous storms, possibly in the form of an MCS, may be ongoing over parts of eastern KS, western MO, and northeast OK Friday morning, with outflow boundaries likely determining precisely where afternoon and evening storms will regenerate. Ample moisture and instability will develop in precipitation-free areas, south of the stationary front and generally from the TX Panhandle eastward. Any outflow boundaries may provide a focus for further development, with localized damaging winds the primary concern. At this time, predictability is to low to focus higher severe probabilities. To the west, capping will exist for much of the day, but the western fringe of the 50s F dewpoints and stronger low-level lapse rates will likely support isolated development over the Front Range. Steep lapse rates aloft along with elongated mid to upper hodographs will favor hail before storms dissipate in the cooler air to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/29/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 PM CDT Thu Aug 29 2019 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered storms, some producing severe wind gusts, are possible over southern Kansas into Oklahoma and the Texas Panhandle on Friday. Other storms capable of mainly hail are expected near the Front Range. ...Synopsis... A large-scale upper trough will move across eastern Canada with a trailing cold front moving across NY and New England. Ahead of this front, a narrow ribbon of dewpoints near 60 F may provide sufficient instability for isolated shallow thunderstorms. To the west, northwest flow aloft will remain over the central and northern Plains and Rockies, with neutral height tendencies. Within this regime, embedded disturbances associated with areas of ongoing storms will exist, mainly from KS into MO. A front will extend eastward from a weak low over the TX Panhandle to near the KS/OK border and into southern MO, providing a focus for additional storms. High pressure will nudge east across the upper MS Valley, maintaining an easterly surface wind component to the central High Plains where 50s F dewpoints support daytime storms. ...Central Plains... Numerous storms, possibly in the form of an MCS, may be ongoing over parts of eastern KS, western MO, and northeast OK Friday morning, with outflow boundaries likely determining precisely where afternoon and evening storms will regenerate. Ample moisture and instability will develop in precipitation-free areas, south of the stationary front and generally from the TX Panhandle eastward. Any outflow boundaries may provide a focus for further development, with localized damaging winds the primary concern. At this time, predictability is to low to focus higher severe probabilities. To the west, capping will exist for much of the day, but the western fringe of the 50s F dewpoints and stronger low-level lapse rates will likely support isolated development over the Front Range. Steep lapse rates aloft along with elongated mid to upper hodographs will favor hail before storms dissipate in the cooler air to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/29/2019 Read more

000
ABPZ20 KNHC 291701
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Thu Aug 29 2019

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

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Stewart

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Thu Aug 29 2019 Valid 291700Z - 301200Z Minimal changes were made to the ongoing isolated dry thunderstorm delineation extending from parts of the Pacific Northwest into the Great Basin and central Rockies. Relatively greater storm coverage may be realized across parts of central/eastern OR later this afternoon and evening, but both precipitable water values and mid-level moisture are also forecast to increase as a shortwave trough approaches this region from the west. Widely scattered storms may also occur across parts of central/eastern UT and southwestern WY today, although mid-level flow and related storm motions quickly decrease with southward extent across the Great Basin. Regardless, little wetting precipitation is expected with this activity given around 0.60-0.80 inch precipitable water values and a well-mixed sub-cloud layer. Any lightning strikes over dry/receptive fuels will have the potential to produce new fire starts. Strong/gusty outflow winds will also be possible. See the previous discussion below for more information. ..Gleason.. 08/29/2019 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Aug 29 2019/ ...Synopsis... An upper-level shortwave trough will impact the Pacific Northwest today. The upper-level ridge over the region will undergo modest weakening in response. Lingering monsoonal moisture across the Great Basin and Pacific Northwest will promote thunderstorms development across these areas. Weak upper-level winds and surface pressure gradients will broadly minimize wind/RH concerns. Locally elevated conditions are possible in parts of Nevada and perhaps south-central Wyoming. ...Pacific Northwest...eastern Great Basin...portions of western Wyoming/Colorado... Isolated thunderstorm activity is possible early in the period across parts of Oregon and southern Washington. This includes the potential for a few lightning strikes on the west side of the Cascades. By mid-morning/early afternoon the threat west of the Cascades will have likely ended. Elsewhere across the highlighted area, continued thunderstorm development is possible during the afternoon. The greatest chance of scattered coverage appears to be in the Wasatch Range vicinity, though PWAT near 1 inch increases the likelihood of wetting rainfall. ...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 1136 AM CDT Thu Aug 29 2019 Valid 291700Z - 301200Z Minimal changes were made to the ongoing isolated dry thunderstorm delineation extending from parts of the Pacific Northwest into the Great Basin and central Rockies. Relatively greater storm coverage may be realized across parts of central/eastern OR later this afternoon and evening, but both precipitable water values and mid-level moisture are also forecast to increase as a shortwave trough approaches this region from the west. Widely scattered storms may also occur across parts of central/eastern UT and southwestern WY today, although mid-level flow and related storm motions quickly decrease with southward extent across the Great Basin. Regardless, little wetting precipitation is expected with this activity given around 0.60-0.80 inch precipitable water values and a well-mixed sub-cloud layer. Any lightning strikes over dry/receptive fuels will have the potential to produce new fire starts. Strong/gusty outflow winds will also be possible. See the previous discussion below for more information. ..Gleason.. 08/29/2019 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Aug 29 2019/ ...Synopsis... An upper-level shortwave trough will impact the Pacific Northwest today. The upper-level ridge over the region will undergo modest weakening in response. Lingering monsoonal moisture across the Great Basin and Pacific Northwest will promote thunderstorms development across these areas. Weak upper-level winds and surface pressure gradients will broadly minimize wind/RH concerns. Locally elevated conditions are possible in parts of Nevada and perhaps south-central Wyoming. ...Pacific Northwest...eastern Great Basin...portions of western Wyoming/Colorado... Isolated thunderstorm activity is possible early in the period across parts of Oregon and southern Washington. This includes the potential for a few lightning strikes on the west side of the Cascades. By mid-morning/early afternoon the threat west of the Cascades will have likely ended. Elsewhere across the highlighted area, continued thunderstorm development is possible during the afternoon. The greatest chance of scattered coverage appears to be in the Wasatch Range vicinity, though PWAT near 1 inch increases the likelihood of wetting rainfall. ...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 1136 AM CDT Thu Aug 29 2019 Valid 291700Z - 301200Z Minimal changes were made to the ongoing isolated dry thunderstorm delineation extending from parts of the Pacific Northwest into the Great Basin and central Rockies. Relatively greater storm coverage may be realized across parts of central/eastern OR later this afternoon and evening, but both precipitable water values and mid-level moisture are also forecast to increase as a shortwave trough approaches this region from the west. Widely scattered storms may also occur across parts of central/eastern UT and southwestern WY today, although mid-level flow and related storm motions quickly decrease with southward extent across the Great Basin. Regardless, little wetting precipitation is expected with this activity given around 0.60-0.80 inch precipitable water values and a well-mixed sub-cloud layer. Any lightning strikes over dry/receptive fuels will have the potential to produce new fire starts. Strong/gusty outflow winds will also be possible. See the previous discussion below for more information. ..Gleason.. 08/29/2019 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Aug 29 2019/ ...Synopsis... An upper-level shortwave trough will impact the Pacific Northwest today. The upper-level ridge over the region will undergo modest weakening in response. Lingering monsoonal moisture across the Great Basin and Pacific Northwest will promote thunderstorms development across these areas. Weak upper-level winds and surface pressure gradients will broadly minimize wind/RH concerns. Locally elevated conditions are possible in parts of Nevada and perhaps south-central Wyoming. ...Pacific Northwest...eastern Great Basin...portions of western Wyoming/Colorado... Isolated thunderstorm activity is possible early in the period across parts of Oregon and southern Washington. This includes the potential for a few lightning strikes on the west side of the Cascades. By mid-morning/early afternoon the threat west of the Cascades will have likely ended. Elsewhere across the highlighted area, continued thunderstorm development is possible during the afternoon. The greatest chance of scattered coverage appears to be in the Wasatch Range vicinity, though PWAT near 1 inch increases the likelihood of wetting rainfall. ...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 1136 AM CDT Thu Aug 29 2019 Valid 291700Z - 301200Z Minimal changes were made to the ongoing isolated dry thunderstorm delineation extending from parts of the Pacific Northwest into the Great Basin and central Rockies. Relatively greater storm coverage may be realized across parts of central/eastern OR later this afternoon and evening, but both precipitable water values and mid-level moisture are also forecast to increase as a shortwave trough approaches this region from the west. Widely scattered storms may also occur across parts of central/eastern UT and southwestern WY today, although mid-level flow and related storm motions quickly decrease with southward extent across the Great Basin. Regardless, little wetting precipitation is expected with this activity given around 0.60-0.80 inch precipitable water values and a well-mixed sub-cloud layer. Any lightning strikes over dry/receptive fuels will have the potential to produce new fire starts. Strong/gusty outflow winds will also be possible. See the previous discussion below for more information. ..Gleason.. 08/29/2019 .PREV DISCUSSION... /ISSUED 0120 AM CDT Thu Aug 29 2019/ ...Synopsis... An upper-level shortwave trough will impact the Pacific Northwest today. The upper-level ridge over the region will undergo modest weakening in response. Lingering monsoonal moisture across the Great Basin and Pacific Northwest will promote thunderstorms development across these areas. Weak upper-level winds and surface pressure gradients will broadly minimize wind/RH concerns. Locally elevated conditions are possible in parts of Nevada and perhaps south-central Wyoming. ...Pacific Northwest...eastern Great Basin...portions of western Wyoming/Colorado... Isolated thunderstorm activity is possible early in the period across parts of Oregon and southern Washington. This includes the potential for a few lightning strikes on the west side of the Cascades. By mid-morning/early afternoon the threat west of the Cascades will have likely ended. Elsewhere across the highlighted area, continued thunderstorm development is possible during the afternoon. The greatest chance of scattered coverage appears to be in the Wasatch Range vicinity, though PWAT near 1 inch increases the likelihood of wetting rainfall. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Thu Aug 29 2019 Valid 291630Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FROM SOUTHEAST WI TO NORTHERN KS... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon into tonight from northern Kansas to southeast Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...WI/Lower MI this afternoon/evening... Within a belt of broadly cyclonic flow aloft, an embedded shortwave trough/speed max will move over WI/Upper MI this afternoon, driving a surface cold front southeastward across WI/MI. A band of elevated thunderstorms immediately precedes the front across WI as of late morning, and some form of this convection is likely to persist into the afternoon into southeast WI and Lower MI. The degree of surface destabilization prior to frontal passage is the primary concern across WI/Lower MI this afternoon/evening, as the stronger forcing for ascent appears likely to overspread northeast WI/northern Lower MI, just northeast of the more substantial destabilization. Vertical shear profiles will favor supercells if sufficient destabilization can occur prior to frontal passage, though storm coverage is also in doubt northeast of the IA cluster and south of the stronger ascent. Farther southwest, a persistent cluster of thunderstorms will likely be maintained into early afternoon from southeast IA to northeast MO, in a zone of low-level warm advection. Additional storm development is expected west of this cluster late this afternoon/evening as the surface cold front reaches southern IA/northern MO. The background environment with large buoyancy and marginal deep-layer vertical shear appears to favor multicell clusters and some embedded supercells initially, though back-building as clusters/line segments is most probable along the front this evening into tonight. Damaging gusts and large hail will be the main threats. ...Southern NE/northern KS this afternoon through tonight... An embedded speed max over southern WY will translate east-southeastward to the NE/KS border region by early tonight. At the surface, a weak lee cyclone near the southwest NE/northwest KS border this morning will develop southward across western KS by this evening, as a cold front likewise moves southward in the wake of the upper Great Lakes shortwave trough. Strong surface heating is expected beneath steep midlevel lapse rates, and convective inhibition will be largely removed once surface temperatures reach the lower 90s F. Boundary-layer dewpoints of 65-72 F from the cold front/dryline triple point eastward along the front will contribute to strong buoyancy this afternoon (MLCAPE 3000-4000 J/kg), in an environment with effective bulk shear around 35 kt. Thus, a mix of supercells and multicell clusters appears probable, with an attendant threat for large hail and damaging winds. Steep lapse rates will favor a threat for both isolated very large hail with initial supercells, and isolated significant gusts with either supercells or cell mergers this evening into early tonight. Some upscale growth into one or more MCSs appears likely tonight from northwest MO into northern KS with merging clusters along the cold front. ..Thompson/Cook.. 08/29/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Thu Aug 29 2019 Valid 291630Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FROM SOUTHEAST WI TO NORTHERN KS... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon into tonight from northern Kansas to southeast Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...WI/Lower MI this afternoon/evening... Within a belt of broadly cyclonic flow aloft, an embedded shortwave trough/speed max will move over WI/Upper MI this afternoon, driving a surface cold front southeastward across WI/MI. A band of elevated thunderstorms immediately precedes the front across WI as of late morning, and some form of this convection is likely to persist into the afternoon into southeast WI and Lower MI. The degree of surface destabilization prior to frontal passage is the primary concern across WI/Lower MI this afternoon/evening, as the stronger forcing for ascent appears likely to overspread northeast WI/northern Lower MI, just northeast of the more substantial destabilization. Vertical shear profiles will favor supercells if sufficient destabilization can occur prior to frontal passage, though storm coverage is also in doubt northeast of the IA cluster and south of the stronger ascent. Farther southwest, a persistent cluster of thunderstorms will likely be maintained into early afternoon from southeast IA to northeast MO, in a zone of low-level warm advection. Additional storm development is expected west of this cluster late this afternoon/evening as the surface cold front reaches southern IA/northern MO. The background environment with large buoyancy and marginal deep-layer vertical shear appears to favor multicell clusters and some embedded supercells initially, though back-building as clusters/line segments is most probable along the front this evening into tonight. Damaging gusts and large hail will be the main threats. ...Southern NE/northern KS this afternoon through tonight... An embedded speed max over southern WY will translate east-southeastward to the NE/KS border region by early tonight. At the surface, a weak lee cyclone near the southwest NE/northwest KS border this morning will develop southward across western KS by this evening, as a cold front likewise moves southward in the wake of the upper Great Lakes shortwave trough. Strong surface heating is expected beneath steep midlevel lapse rates, and convective inhibition will be largely removed once surface temperatures reach the lower 90s F. Boundary-layer dewpoints of 65-72 F from the cold front/dryline triple point eastward along the front will contribute to strong buoyancy this afternoon (MLCAPE 3000-4000 J/kg), in an environment with effective bulk shear around 35 kt. Thus, a mix of supercells and multicell clusters appears probable, with an attendant threat for large hail and damaging winds. Steep lapse rates will favor a threat for both isolated very large hail with initial supercells, and isolated significant gusts with either supercells or cell mergers this evening into early tonight. Some upscale growth into one or more MCSs appears likely tonight from northwest MO into northern KS with merging clusters along the cold front. ..Thompson/Cook.. 08/29/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Thu Aug 29 2019 Valid 291630Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FROM SOUTHEAST WI TO NORTHERN KS... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon into tonight from northern Kansas to southeast Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...WI/Lower MI this afternoon/evening... Within a belt of broadly cyclonic flow aloft, an embedded shortwave trough/speed max will move over WI/Upper MI this afternoon, driving a surface cold front southeastward across WI/MI. A band of elevated thunderstorms immediately precedes the front across WI as of late morning, and some form of this convection is likely to persist into the afternoon into southeast WI and Lower MI. The degree of surface destabilization prior to frontal passage is the primary concern across WI/Lower MI this afternoon/evening, as the stronger forcing for ascent appears likely to overspread northeast WI/northern Lower MI, just northeast of the more substantial destabilization. Vertical shear profiles will favor supercells if sufficient destabilization can occur prior to frontal passage, though storm coverage is also in doubt northeast of the IA cluster and south of the stronger ascent. Farther southwest, a persistent cluster of thunderstorms will likely be maintained into early afternoon from southeast IA to northeast MO, in a zone of low-level warm advection. Additional storm development is expected west of this cluster late this afternoon/evening as the surface cold front reaches southern IA/northern MO. The background environment with large buoyancy and marginal deep-layer vertical shear appears to favor multicell clusters and some embedded supercells initially, though back-building as clusters/line segments is most probable along the front this evening into tonight. Damaging gusts and large hail will be the main threats. ...Southern NE/northern KS this afternoon through tonight... An embedded speed max over southern WY will translate east-southeastward to the NE/KS border region by early tonight. At the surface, a weak lee cyclone near the southwest NE/northwest KS border this morning will develop southward across western KS by this evening, as a cold front likewise moves southward in the wake of the upper Great Lakes shortwave trough. Strong surface heating is expected beneath steep midlevel lapse rates, and convective inhibition will be largely removed once surface temperatures reach the lower 90s F. Boundary-layer dewpoints of 65-72 F from the cold front/dryline triple point eastward along the front will contribute to strong buoyancy this afternoon (MLCAPE 3000-4000 J/kg), in an environment with effective bulk shear around 35 kt. Thus, a mix of supercells and multicell clusters appears probable, with an attendant threat for large hail and damaging winds. Steep lapse rates will favor a threat for both isolated very large hail with initial supercells, and isolated significant gusts with either supercells or cell mergers this evening into early tonight. Some upscale growth into one or more MCSs appears likely tonight from northwest MO into northern KS with merging clusters along the cold front. ..Thompson/Cook.. 08/29/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Thu Aug 29 2019 Valid 291630Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FROM SOUTHEAST WI TO NORTHERN KS... ...SUMMARY... Scattered severe thunderstorms are possible this afternoon into tonight from northern Kansas to southeast Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...WI/Lower MI this afternoon/evening... Within a belt of broadly cyclonic flow aloft, an embedded shortwave trough/speed max will move over WI/Upper MI this afternoon, driving a surface cold front southeastward across WI/MI. A band of elevated thunderstorms immediately precedes the front across WI as of late morning, and some form of this convection is likely to persist into the afternoon into southeast WI and Lower MI. The degree of surface destabilization prior to frontal passage is the primary concern across WI/Lower MI this afternoon/evening, as the stronger forcing for ascent appears likely to overspread northeast WI/northern Lower MI, just northeast of the more substantial destabilization. Vertical shear profiles will favor supercells if sufficient destabilization can occur prior to frontal passage, though storm coverage is also in doubt northeast of the IA cluster and south of the stronger ascent. Farther southwest, a persistent cluster of thunderstorms will likely be maintained into early afternoon from southeast IA to northeast MO, in a zone of low-level warm advection. Additional storm development is expected west of this cluster late this afternoon/evening as the surface cold front reaches southern IA/northern MO. The background environment with large buoyancy and marginal deep-layer vertical shear appears to favor multicell clusters and some embedded supercells initially, though back-building as clusters/line segments is most probable along the front this evening into tonight. Damaging gusts and large hail will be the main threats. ...Southern NE/northern KS this afternoon through tonight... An embedded speed max over southern WY will translate east-southeastward to the NE/KS border region by early tonight. At the surface, a weak lee cyclone near the southwest NE/northwest KS border this morning will develop southward across western KS by this evening, as a cold front likewise moves southward in the wake of the upper Great Lakes shortwave trough. Strong surface heating is expected beneath steep midlevel lapse rates, and convective inhibition will be largely removed once surface temperatures reach the lower 90s F. Boundary-layer dewpoints of 65-72 F from the cold front/dryline triple point eastward along the front will contribute to strong buoyancy this afternoon (MLCAPE 3000-4000 J/kg), in an environment with effective bulk shear around 35 kt. Thus, a mix of supercells and multicell clusters appears probable, with an attendant threat for large hail and damaging winds. Steep lapse rates will favor a threat for both isolated very large hail with initial supercells, and isolated significant gusts with either supercells or cell mergers this evening into early tonight. Some upscale growth into one or more MCSs appears likely tonight from northwest MO into northern KS with merging clusters along the cold front. ..Thompson/Cook.. 08/29/2019 Read more

MD 1884 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHEAST IOWA...NORTHEAST MISSOURI AND ADJACENT WEST CENTRAL ILLINOIS
Mesoscale Discussion 1884 NWS Storm Prediction Center Norman OK 1055 AM CDT Thu Aug 29 2019 Areas affected...Parts of southeast Iowa...northeast Missouri and adjacent west central Illinois Concerning...Severe potential...Watch unlikely Valid 291555Z - 291730Z Probability of Watch Issuance...20 percent SUMMARY...Strong storms may pose at least some risk for severe hail and strong surface gusts into midday, before diminishing. Due to the expected marginal and short-lived nature of this threat, a severe weather watch is not anticipated, but trends will be monitored. DISCUSSION...A sustained area of thunderstorm development has been spreading east-southeastward across southern Iowa, likely primarily supported and rooted within an area of forcing for ascent associated with warm advection accompanying a 30-35 kt west-northwesterly 850 mb jet. Inflow of air originating from the moist and warming boundary layer over the mid Missouri Valley probably has contributed to recent intensification near the northern Missouri state border, southwest of Ottumwa IA. In the presence of strong deep-layer shear within the convective layer, inflow CAPE may now be in excess of 2000 J/kg, contributing to convection capable of producing severe hail. Some risk for strong surface gusts could eventually develop as activity continues to develop east-southeastward through midday. However, models suggest that the supporting forcing/low-level jet will gradually weaken while shifting across the remainder of southern Iowa into central Illinois. Current convective intensities and associated severe weather potential may be fairly short-lived. Some destabilization of the boundary layer is occurring to the south of the ongoing storm cluster, across northern Missouri into central Illinois, in response to insolation and low-level moisture advection. However, although not out of the question, it currently appears unlikely to destabilize rapidly enough to allow for convection to begin to take root within the boundary layer, along the developing cold pool, before the ongoing "elevated" activity begins to dissipate. ..Kerr/Thompson.. 08/29/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILX...LSX...DVN...DMX...EAX... LAT...LON 41219319 41039138 40588996 39689042 39719201 40429317 41219319 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Thu Aug 29 2019 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF KS/NE TO SOUTHERN WI... ...SUMMARY... Scattered severe thunderstorms are probable this afternoon into tonight from the central Great Plains to southern Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...Mid-MO Valley to central Great Lakes... A vigorous shortwave trough near the MN/ON border will rapidly progress into western QC by early Friday. Mid-level height falls with this feature will generally be confined to northern portions of WI/MI. A surface cold front will sweep east and push south, extending from eastern WI/Upper MI southwest towards the KS/NE border at 21Z. Low-level warm advection-driven convection is ongoing across central/southern IA along the leading edge of moisture return from the central and southern Great Plains. This activity should persist through the day as simulated by recent NCEP/ESRL-HRRR runs, while additional elevated convection has recently formed in northwest WI closer to the shortwave trough. The low-level moisture plume will be rather confined with northeast extent but should support increasing surface dew points from the southwest as mixing ensues. Confidence is not particularly high with the degree of surface-based buoyancy indicated by guidance given the persistence of early-day elevated storms and the need for substantial moist advection/mixing. Even with more muted buoyancy, deep-layer shear will be pronounced (effective values of 35-50 kt) and favorable for organized updrafts/clusters with any pockets of convection that can be sustained near the front during the late afternoon to early evening. Thus, will refrain from making any substantial changes to the Marginal and Slight Risks with this outlook. ...Central Great Plains... Most guidance is fairly consistent in sustaining late afternoon storm development near the intersection of the southward-moving cold front and dryline along the southwest NE/northwest KS border. A minor mid-level impulse is expected to approach this region from southwest WY, yielding some enhancement to west-northwesterlies aloft. With hot surface temperatures across western KS, increasingly rich low-level moisture near the front, and a plume of rather steep mid-level lapse rates, a few supercells may form prior to growing upscale into a large MCS tonight towards the Lower MO Valley. Large hail and a tornado will be possible early, with severe wind gusts likely becoming the primary threat into the overnight as a 30-35 kt low-level jet develops from the southern High Plains to central KS. ..Grams/Mosier.. 08/29/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Thu Aug 29 2019 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF KS/NE TO SOUTHERN WI... ...SUMMARY... Scattered severe thunderstorms are probable this afternoon into tonight from the central Great Plains to southern Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...Mid-MO Valley to central Great Lakes... A vigorous shortwave trough near the MN/ON border will rapidly progress into western QC by early Friday. Mid-level height falls with this feature will generally be confined to northern portions of WI/MI. A surface cold front will sweep east and push south, extending from eastern WI/Upper MI southwest towards the KS/NE border at 21Z. Low-level warm advection-driven convection is ongoing across central/southern IA along the leading edge of moisture return from the central and southern Great Plains. This activity should persist through the day as simulated by recent NCEP/ESRL-HRRR runs, while additional elevated convection has recently formed in northwest WI closer to the shortwave trough. The low-level moisture plume will be rather confined with northeast extent but should support increasing surface dew points from the southwest as mixing ensues. Confidence is not particularly high with the degree of surface-based buoyancy indicated by guidance given the persistence of early-day elevated storms and the need for substantial moist advection/mixing. Even with more muted buoyancy, deep-layer shear will be pronounced (effective values of 35-50 kt) and favorable for organized updrafts/clusters with any pockets of convection that can be sustained near the front during the late afternoon to early evening. Thus, will refrain from making any substantial changes to the Marginal and Slight Risks with this outlook. ...Central Great Plains... Most guidance is fairly consistent in sustaining late afternoon storm development near the intersection of the southward-moving cold front and dryline along the southwest NE/northwest KS border. A minor mid-level impulse is expected to approach this region from southwest WY, yielding some enhancement to west-northwesterlies aloft. With hot surface temperatures across western KS, increasingly rich low-level moisture near the front, and a plume of rather steep mid-level lapse rates, a few supercells may form prior to growing upscale into a large MCS tonight towards the Lower MO Valley. Large hail and a tornado will be possible early, with severe wind gusts likely becoming the primary threat into the overnight as a 30-35 kt low-level jet develops from the southern High Plains to central KS. ..Grams/Mosier.. 08/29/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Thu Aug 29 2019 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF KS/NE TO SOUTHERN WI... ...SUMMARY... Scattered severe thunderstorms are probable this afternoon into tonight from the central Great Plains to southern Wisconsin. Large hail, damaging winds, and a tornado or two will be possible. ...Mid-MO Valley to central Great Lakes... A vigorous shortwave trough near the MN/ON border will rapidly progress into western QC by early Friday. Mid-level height falls with this feature will generally be confined to northern portions of WI/MI. A surface cold front will sweep east and push south, extending from eastern WI/Upper MI southwest towards the KS/NE border at 21Z. Low-level warm advection-driven convection is ongoing across central/southern IA along the leading edge of moisture return from the central and southern Great Plains. This activity should persist through the day as simulated by recent NCEP/ESRL-HRRR runs, while additional elevated convection has recently formed in northwest WI closer to the shortwave trough. The low-level moisture plume will be rather confined with northeast extent but should support increasing surface dew points from the southwest as mixing ensues. Confidence is not particularly high with the degree of surface-based buoyancy indicated by guidance given the persistence of early-day elevated storms and the need for substantial moist advection/mixing. Even with more muted buoyancy, deep-layer shear will be pronounced (effective values of 35-50 kt) and favorable for organized updrafts/clusters with any pockets of convection that can be sustained near the front during the late afternoon to early evening. Thus, will refrain from making any substantial changes to the Marginal and Slight Risks with this outlook. ...Central Great Plains... Most guidance is fairly consistent in sustaining late afternoon storm development near the intersection of the southward-moving cold front and dryline along the southwest NE/northwest KS border. A minor mid-level impulse is expected to approach this region from southwest WY, yielding some enhancement to west-northwesterlies aloft. With hot surface temperatures across western KS, increasingly rich low-level moisture near the front, and a plume of rather steep mid-level lapse rates, a few supercells may form prior to growing upscale into a large MCS tonight towards the Lower MO Valley. Large hail and a tornado will be possible early, with severe wind gusts likely becoming the primary threat into the overnight as a 30-35 kt low-level jet develops from the southern High Plains to central KS. ..Grams/Mosier.. 08/29/2019 Read more

000
ABPZ20 KNHC 291129
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Thu Aug 29 2019

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

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Stewart

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0326 AM CDT Thu Aug 29 2019 Valid 011200Z - 061200Z ...DISCUSSION... A mean upper level trough will persist over the eastern U.S. during the Day 4-8 period. Guidance is not in very good agreement in regards to the position of the western upper ridge (centered over the High Plains vs. remaining west of the Rockies), or in terms of shortwave impulses migrating through northwesterly flow into the eastern trough. The evolution of a shortwave trough moving into/across the Pacific Northwest early to mid-week is also forecast very different by the GFS vs. ECMWF. It appears that some severe threat will be possible from the Upper Midwest to the Great Lakes and Northeast Days 4-7/Sun-Wed, but confidence is low given poor consistency in forecast guidance. Hurricane Dorian will approach the east coast of the FL Peninsula on Sunday, with potential landfall now expected on Monday as guidance as trended slower in the storms west/northwest track. Depending on the exact track as the hurricane approaches FL and then after landfall toward the end of the work week, some TC-related tornado threat is possible across portions of the southeastern U.S. This threat will be addressed in coordination with the National Hurricane Center in the coming days as confidence in the forecast track increases. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0326 AM CDT Thu Aug 29 2019 Valid 011200Z - 061200Z ...DISCUSSION... A mean upper level trough will persist over the eastern U.S. during the Day 4-8 period. Guidance is not in very good agreement in regards to the position of the western upper ridge (centered over the High Plains vs. remaining west of the Rockies), or in terms of shortwave impulses migrating through northwesterly flow into the eastern trough. The evolution of a shortwave trough moving into/across the Pacific Northwest early to mid-week is also forecast very different by the GFS vs. ECMWF. It appears that some severe threat will be possible from the Upper Midwest to the Great Lakes and Northeast Days 4-7/Sun-Wed, but confidence is low given poor consistency in forecast guidance. Hurricane Dorian will approach the east coast of the FL Peninsula on Sunday, with potential landfall now expected on Monday as guidance as trended slower in the storms west/northwest track. Depending on the exact track as the hurricane approaches FL and then after landfall toward the end of the work week, some TC-related tornado threat is possible across portions of the southeastern U.S. This threat will be addressed in coordination with the National Hurricane Center in the coming days as confidence in the forecast track increases. Read more