Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Tue Sep 03 2019 Valid 041200Z - 051200Z ...Synopsis... An upper-level ridge will remain in place across the western CONUS for the Day 2/Wednesday period. The embedded mid-level shortwave trough moving across the Pacific Northwest on Day 1 will then traverse the northern Rockies while cresting the ridge on Day 2. With the passage of the trough, the low-level mass response will be a dry and breezy westerly wind that may foster some wildfire-spread potential. Elsewhere, from northern California into the Great Basin, adequate monsoonal moisture traversing the upper-level ridge will promote at least isolated thunderstorm potential, with a few dry strikes possible. ...Northern Rockies... With the passage of an upper-level trough and diurnal boundary layer mixing of stronger winds aloft to the surface, 15-25 mph sustained westerly surface winds are expected across parts of the northern Rockies (mainly north-central Montana) along with 15-25% RH. Finer fuels have recently begun to dry across the area, supporting the potential for grass-fire spread and as such, an elevated area has been delineated. ...Northern California into the northern Great Basin... As mid-level monsoonal moisture continues to drift northward across northern portions of the Great Basin, isolated high-based thunderstorms will become possible by afternoon peak heating. Despite slow storm motions, a dry sub-cloud layer will support at least some potential for dry strikes atop near-critical to critically dry fuels, where an isolated dry thunderstorm area was added. Isolated dry thunderstorms may also occur over northern parts of California into far southern Oregon, but low confidence in storm initiation over this area precludes a delineation at this time. ..Squitieri.. 09/03/2019 ...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 0201 AM CDT Tue Sep 03 2019 Valid 041200Z - 051200Z ...Synopsis... An upper-level ridge will remain in place across the western CONUS for the Day 2/Wednesday period. The embedded mid-level shortwave trough moving across the Pacific Northwest on Day 1 will then traverse the northern Rockies while cresting the ridge on Day 2. With the passage of the trough, the low-level mass response will be a dry and breezy westerly wind that may foster some wildfire-spread potential. Elsewhere, from northern California into the Great Basin, adequate monsoonal moisture traversing the upper-level ridge will promote at least isolated thunderstorm potential, with a few dry strikes possible. ...Northern Rockies... With the passage of an upper-level trough and diurnal boundary layer mixing of stronger winds aloft to the surface, 15-25 mph sustained westerly surface winds are expected across parts of the northern Rockies (mainly north-central Montana) along with 15-25% RH. Finer fuels have recently begun to dry across the area, supporting the potential for grass-fire spread and as such, an elevated area has been delineated. ...Northern California into the northern Great Basin... As mid-level monsoonal moisture continues to drift northward across northern portions of the Great Basin, isolated high-based thunderstorms will become possible by afternoon peak heating. Despite slow storm motions, a dry sub-cloud layer will support at least some potential for dry strikes atop near-critical to critically dry fuels, where an isolated dry thunderstorm area was added. Isolated dry thunderstorms may also occur over northern parts of California into far southern Oregon, but low confidence in storm initiation over this area precludes a delineation at this time. ..Squitieri.. 09/03/2019 ...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 0201 AM CDT Tue Sep 03 2019 Valid 041200Z - 051200Z ...Synopsis... An upper-level ridge will remain in place across the western CONUS for the Day 2/Wednesday period. The embedded mid-level shortwave trough moving across the Pacific Northwest on Day 1 will then traverse the northern Rockies while cresting the ridge on Day 2. With the passage of the trough, the low-level mass response will be a dry and breezy westerly wind that may foster some wildfire-spread potential. Elsewhere, from northern California into the Great Basin, adequate monsoonal moisture traversing the upper-level ridge will promote at least isolated thunderstorm potential, with a few dry strikes possible. ...Northern Rockies... With the passage of an upper-level trough and diurnal boundary layer mixing of stronger winds aloft to the surface, 15-25 mph sustained westerly surface winds are expected across parts of the northern Rockies (mainly north-central Montana) along with 15-25% RH. Finer fuels have recently begun to dry across the area, supporting the potential for grass-fire spread and as such, an elevated area has been delineated. ...Northern California into the northern Great Basin... As mid-level monsoonal moisture continues to drift northward across northern portions of the Great Basin, isolated high-based thunderstorms will become possible by afternoon peak heating. Despite slow storm motions, a dry sub-cloud layer will support at least some potential for dry strikes atop near-critical to critically dry fuels, where an isolated dry thunderstorm area was added. Isolated dry thunderstorms may also occur over northern parts of California into far southern Oregon, but low confidence in storm initiation over this area precludes a delineation at this time. ..Squitieri.. 09/03/2019 ...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 0112 AM CDT Tue Sep 03 2019 Valid 031200Z - 041200Z ...Synopsis... A mid-level ridge will remain in place across the western CONUS, with an embedded shortwave trough propagating around the ridge across the Pacific Northwest. Mildly dry and breezy conditions may occur east of the Cascades as the stronger flow aloft attempts to mix downward to the surface. Mid-level monsoonal moisture will also be present across parts of the Great Basin, fueling isolated thunderstorms, with a few dry strikes possible. ...Pacific Northwest... By afternoon peak heating, boundary layer mixing, in conjunction with downslope flow along the lee of the Cascades, will contribute to westerly winds reaching 15 mph at times, particularly in the Harney Basin area, with RH dropping into the 15-25% range. As winds exceeding 15 mph will be brief and confined to mainly terrain favoring locations, an elevated delineation has been withheld at this time. ...Portions of the Great Basin... Mid-level moisture will meander northwestward into central parts of the Great Basin (including parts of Nevada into western Utah), where afternoon heating will provide enough buoyancy and lift to induce isolated thunderstorms. Though these storms will be slow moving, cells are expected to be high based in nature (i.e. rooted atop a sfc-500 mb dry sub-cloud layer), and are expected to occur over fuels that are near-critical to critically receptive to fire spread, warranting the addition of an isolated dry thunderstorm delineation. ..Squitieri.. 09/03/2019 ...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 0112 AM CDT Tue Sep 03 2019 Valid 031200Z - 041200Z ...Synopsis... A mid-level ridge will remain in place across the western CONUS, with an embedded shortwave trough propagating around the ridge across the Pacific Northwest. Mildly dry and breezy conditions may occur east of the Cascades as the stronger flow aloft attempts to mix downward to the surface. Mid-level monsoonal moisture will also be present across parts of the Great Basin, fueling isolated thunderstorms, with a few dry strikes possible. ...Pacific Northwest... By afternoon peak heating, boundary layer mixing, in conjunction with downslope flow along the lee of the Cascades, will contribute to westerly winds reaching 15 mph at times, particularly in the Harney Basin area, with RH dropping into the 15-25% range. As winds exceeding 15 mph will be brief and confined to mainly terrain favoring locations, an elevated delineation has been withheld at this time. ...Portions of the Great Basin... Mid-level moisture will meander northwestward into central parts of the Great Basin (including parts of Nevada into western Utah), where afternoon heating will provide enough buoyancy and lift to induce isolated thunderstorms. Though these storms will be slow moving, cells are expected to be high based in nature (i.e. rooted atop a sfc-500 mb dry sub-cloud layer), and are expected to occur over fuels that are near-critical to critically receptive to fire spread, warranting the addition of an isolated dry thunderstorm delineation. ..Squitieri.. 09/03/2019 ...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 0112 AM CDT Tue Sep 03 2019 Valid 031200Z - 041200Z ...Synopsis... A mid-level ridge will remain in place across the western CONUS, with an embedded shortwave trough propagating around the ridge across the Pacific Northwest. Mildly dry and breezy conditions may occur east of the Cascades as the stronger flow aloft attempts to mix downward to the surface. Mid-level monsoonal moisture will also be present across parts of the Great Basin, fueling isolated thunderstorms, with a few dry strikes possible. ...Pacific Northwest... By afternoon peak heating, boundary layer mixing, in conjunction with downslope flow along the lee of the Cascades, will contribute to westerly winds reaching 15 mph at times, particularly in the Harney Basin area, with RH dropping into the 15-25% range. As winds exceeding 15 mph will be brief and confined to mainly terrain favoring locations, an elevated delineation has been withheld at this time. ...Portions of the Great Basin... Mid-level moisture will meander northwestward into central parts of the Great Basin (including parts of Nevada into western Utah), where afternoon heating will provide enough buoyancy and lift to induce isolated thunderstorms. Though these storms will be slow moving, cells are expected to be high based in nature (i.e. rooted atop a sfc-500 mb dry sub-cloud layer), and are expected to occur over fuels that are near-critical to critically receptive to fire spread, warranting the addition of an isolated dry thunderstorm delineation. ..Squitieri.. 09/03/2019 ...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 1237 AM CDT Tue Sep 03 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW ENGLAND INTO THE MIDDLE ATLANTIC AND FROM COASTAL GEORGIA TO COASTAL SOUTH CAROLINA... ...SUMMARY... A couple of tornadoes are possible along the Georgia and south Carolina coastal areas Wednesday afternoon through Wednesday night in association with Hurricane Dorian. Otherwise, isolated damaging gusts are possible Wednesday afternoon from the Middle Atlantic through New England. ...Georgia and South Carolina coasts... Hurricane Dorian is forecast by the National Hurricane Center to begin a slow northwestward motion and should be located off the GA coast Wednesday afternoon based on the latest forecast. The most favorable quadrant for a more robust tornado threat will remain offshore. However, thunderstorms developing within the outer rain bands will spread inland, and low-level hodographs might become sufficient for at least a marginal isolated tornado threat along the GA and SC coast Wednesday afternoon and evening. See latest discussions from the National Hurricane center for updates on Dorian. ...Middle Atlantic through New England... A cold front will accompany a shortwave trough as it moves through the northeast states Wednesday afternoon. Low-level dewpoints in the 60s F will advect through pre-frontal warm sector, but areas of clouds and modest mid-level lapse rates should limit MLCAPE to near 500 J/kg over New England. A few showers and thunderstorms will probably be ongoing along warm conveyor belt just ahead of the cold front from NY into PA. Additional development/intensification will be possible downstream across New England as the atmosphere destabilizes. The strongest deep-layer shear (50+ kt) supportive of organized severe storms will reside across New England where instability should be weaker. Given this potential limiting factor, will maintain a MRGL risk this outlook, but a categorical upgrade might be needed in later updates if it begins to appear instability will be greater than currently anticipated. Other storms will likely develop along and ahead of the front as far south as the middle Atlantic region where instability will be greater (up to 1500 J/kg MLCAPE). These storms will reside in a weaker shear environment supportive of multicells with a risk for isolated damaging wind during the afternoon. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Dial.. 09/03/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1237 AM CDT Tue Sep 03 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW ENGLAND INTO THE MIDDLE ATLANTIC AND FROM COASTAL GEORGIA TO COASTAL SOUTH CAROLINA... ...SUMMARY... A couple of tornadoes are possible along the Georgia and south Carolina coastal areas Wednesday afternoon through Wednesday night in association with Hurricane Dorian. Otherwise, isolated damaging gusts are possible Wednesday afternoon from the Middle Atlantic through New England. ...Georgia and South Carolina coasts... Hurricane Dorian is forecast by the National Hurricane Center to begin a slow northwestward motion and should be located off the GA coast Wednesday afternoon based on the latest forecast. The most favorable quadrant for a more robust tornado threat will remain offshore. However, thunderstorms developing within the outer rain bands will spread inland, and low-level hodographs might become sufficient for at least a marginal isolated tornado threat along the GA and SC coast Wednesday afternoon and evening. See latest discussions from the National Hurricane center for updates on Dorian. ...Middle Atlantic through New England... A cold front will accompany a shortwave trough as it moves through the northeast states Wednesday afternoon. Low-level dewpoints in the 60s F will advect through pre-frontal warm sector, but areas of clouds and modest mid-level lapse rates should limit MLCAPE to near 500 J/kg over New England. A few showers and thunderstorms will probably be ongoing along warm conveyor belt just ahead of the cold front from NY into PA. Additional development/intensification will be possible downstream across New England as the atmosphere destabilizes. The strongest deep-layer shear (50+ kt) supportive of organized severe storms will reside across New England where instability should be weaker. Given this potential limiting factor, will maintain a MRGL risk this outlook, but a categorical upgrade might be needed in later updates if it begins to appear instability will be greater than currently anticipated. Other storms will likely develop along and ahead of the front as far south as the middle Atlantic region where instability will be greater (up to 1500 J/kg MLCAPE). These storms will reside in a weaker shear environment supportive of multicells with a risk for isolated damaging wind during the afternoon. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Dial.. 09/03/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1237 AM CDT Tue Sep 03 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW ENGLAND INTO THE MIDDLE ATLANTIC AND FROM COASTAL GEORGIA TO COASTAL SOUTH CAROLINA... ...SUMMARY... A couple of tornadoes are possible along the Georgia and south Carolina coastal areas Wednesday afternoon through Wednesday night in association with Hurricane Dorian. Otherwise, isolated damaging gusts are possible Wednesday afternoon from the Middle Atlantic through New England. ...Georgia and South Carolina coasts... Hurricane Dorian is forecast by the National Hurricane Center to begin a slow northwestward motion and should be located off the GA coast Wednesday afternoon based on the latest forecast. The most favorable quadrant for a more robust tornado threat will remain offshore. However, thunderstorms developing within the outer rain bands will spread inland, and low-level hodographs might become sufficient for at least a marginal isolated tornado threat along the GA and SC coast Wednesday afternoon and evening. See latest discussions from the National Hurricane center for updates on Dorian. ...Middle Atlantic through New England... A cold front will accompany a shortwave trough as it moves through the northeast states Wednesday afternoon. Low-level dewpoints in the 60s F will advect through pre-frontal warm sector, but areas of clouds and modest mid-level lapse rates should limit MLCAPE to near 500 J/kg over New England. A few showers and thunderstorms will probably be ongoing along warm conveyor belt just ahead of the cold front from NY into PA. Additional development/intensification will be possible downstream across New England as the atmosphere destabilizes. The strongest deep-layer shear (50+ kt) supportive of organized severe storms will reside across New England where instability should be weaker. Given this potential limiting factor, will maintain a MRGL risk this outlook, but a categorical upgrade might be needed in later updates if it begins to appear instability will be greater than currently anticipated. Other storms will likely develop along and ahead of the front as far south as the middle Atlantic region where instability will be greater (up to 1500 J/kg MLCAPE). These storms will reside in a weaker shear environment supportive of multicells with a risk for isolated damaging wind during the afternoon. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Dial.. 09/03/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Tue Sep 03 2019 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF LOWER MI INTO THE MIDWEST... ...SUMMARY... Severe storms may occur today from parts of Lower Michigan southwestward into Illinois, Indiana, and Ohio. Isolated damaging winds and large hail should be the main threats, but a couple tornadoes will also be possible. ...Midwest into the Great Lakes and Mid MS Valley... A long-lived MCS over far southeastern MN and western/central WI early this morning will likely continue southeastward across WI for at least the next several hours along an instability gradient. This line of storms should continue to gradually weaken with southeastward extent this morning as it encounters a less unstable airmass. However, strong low/mid-level flow associated with a shortwave trough over the northern Plains may allow these storms to persist for longer than most model guidance suggests. An isolated hail/wind threat may be ongoing at the start of the period across parts of northern IL and vicinity if these storms can maintain their intensity, especially on the southwestern flank of the line where instability is relatively greater. The convective scenario for today remains rather uncertain given the potential for this morning MCS to delay/disrupt diurnal destabilization, particularly with northward extent into Lower MI. A relatively greater chance for moderate to strong instability to develop may occur along a trailing outflow boundary from these morning storms across parts of northern IL/IN into far southern Lower MI. Strong large-scale forcing for ascent attendant to a southeastward-moving shortwave trough will overspread these areas by this afternoon. Additional convective development appears likely along or just ahead of a surface cold front by peak afternoon heating. The presence of a 50-70+ kt mid-level westerly jet will support strong effective bulk shear values over this region. Any storms that can form in this environment will likely become organized and pose an isolated large hail and damaging wind threat. Initially semi-discrete storms will probably grow upscale fairly quickly along the cold front or remnant outflow boundary, with a damaging wind threat potentially continuing into the evening across parts of central IL/IN and northwestern OH. The degree of the tornado threat will be dependent on storm mode, but a southwesterly low-level jet will overspread much of the warm sector through the afternoon. Isolated tornadoes will be possible given the strong low-level shear that will be present. Greater severe probabilities may be needed across some part of the Midwest into southern Lower MI, but too much uncertainty exists regarding morning storms to introduce them at them at this time. ...Florida... Latest forecast from the National Hurricane Center shows Hurricane Dorian should remain just offshore the east coast of the FL Peninsula today through tonight. However, low-level convergence and banded convection within the western half of the system will spread slowly northward. While tornadoes are generally not favored along the west side of the track, effective SRH around 200 m2/s2 during the day increasing to over 300 m2/s2 into early Wednesday morning may support a couple rotating storms with a brief/weak tornado risk. ..Gleason/Squitieri.. 09/03/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Tue Sep 03 2019 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF LOWER MI INTO THE MIDWEST... ...SUMMARY... Severe storms may occur today from parts of Lower Michigan southwestward into Illinois, Indiana, and Ohio. Isolated damaging winds and large hail should be the main threats, but a couple tornadoes will also be possible. ...Midwest into the Great Lakes and Mid MS Valley... A long-lived MCS over far southeastern MN and western/central WI early this morning will likely continue southeastward across WI for at least the next several hours along an instability gradient. This line of storms should continue to gradually weaken with southeastward extent this morning as it encounters a less unstable airmass. However, strong low/mid-level flow associated with a shortwave trough over the northern Plains may allow these storms to persist for longer than most model guidance suggests. An isolated hail/wind threat may be ongoing at the start of the period across parts of northern IL and vicinity if these storms can maintain their intensity, especially on the southwestern flank of the line where instability is relatively greater. The convective scenario for today remains rather uncertain given the potential for this morning MCS to delay/disrupt diurnal destabilization, particularly with northward extent into Lower MI. A relatively greater chance for moderate to strong instability to develop may occur along a trailing outflow boundary from these morning storms across parts of northern IL/IN into far southern Lower MI. Strong large-scale forcing for ascent attendant to a southeastward-moving shortwave trough will overspread these areas by this afternoon. Additional convective development appears likely along or just ahead of a surface cold front by peak afternoon heating. The presence of a 50-70+ kt mid-level westerly jet will support strong effective bulk shear values over this region. Any storms that can form in this environment will likely become organized and pose an isolated large hail and damaging wind threat. Initially semi-discrete storms will probably grow upscale fairly quickly along the cold front or remnant outflow boundary, with a damaging wind threat potentially continuing into the evening across parts of central IL/IN and northwestern OH. The degree of the tornado threat will be dependent on storm mode, but a southwesterly low-level jet will overspread much of the warm sector through the afternoon. Isolated tornadoes will be possible given the strong low-level shear that will be present. Greater severe probabilities may be needed across some part of the Midwest into southern Lower MI, but too much uncertainty exists regarding morning storms to introduce them at them at this time. ...Florida... Latest forecast from the National Hurricane Center shows Hurricane Dorian should remain just offshore the east coast of the FL Peninsula today through tonight. However, low-level convergence and banded convection within the western half of the system will spread slowly northward. While tornadoes are generally not favored along the west side of the track, effective SRH around 200 m2/s2 during the day increasing to over 300 m2/s2 into early Wednesday morning may support a couple rotating storms with a brief/weak tornado risk. ..Gleason/Squitieri.. 09/03/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Tue Sep 03 2019 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF LOWER MI INTO THE MIDWEST... ...SUMMARY... Severe storms may occur today from parts of Lower Michigan southwestward into Illinois, Indiana, and Ohio. Isolated damaging winds and large hail should be the main threats, but a couple tornadoes will also be possible. ...Midwest into the Great Lakes and Mid MS Valley... A long-lived MCS over far southeastern MN and western/central WI early this morning will likely continue southeastward across WI for at least the next several hours along an instability gradient. This line of storms should continue to gradually weaken with southeastward extent this morning as it encounters a less unstable airmass. However, strong low/mid-level flow associated with a shortwave trough over the northern Plains may allow these storms to persist for longer than most model guidance suggests. An isolated hail/wind threat may be ongoing at the start of the period across parts of northern IL and vicinity if these storms can maintain their intensity, especially on the southwestern flank of the line where instability is relatively greater. The convective scenario for today remains rather uncertain given the potential for this morning MCS to delay/disrupt diurnal destabilization, particularly with northward extent into Lower MI. A relatively greater chance for moderate to strong instability to develop may occur along a trailing outflow boundary from these morning storms across parts of northern IL/IN into far southern Lower MI. Strong large-scale forcing for ascent attendant to a southeastward-moving shortwave trough will overspread these areas by this afternoon. Additional convective development appears likely along or just ahead of a surface cold front by peak afternoon heating. The presence of a 50-70+ kt mid-level westerly jet will support strong effective bulk shear values over this region. Any storms that can form in this environment will likely become organized and pose an isolated large hail and damaging wind threat. Initially semi-discrete storms will probably grow upscale fairly quickly along the cold front or remnant outflow boundary, with a damaging wind threat potentially continuing into the evening across parts of central IL/IN and northwestern OH. The degree of the tornado threat will be dependent on storm mode, but a southwesterly low-level jet will overspread much of the warm sector through the afternoon. Isolated tornadoes will be possible given the strong low-level shear that will be present. Greater severe probabilities may be needed across some part of the Midwest into southern Lower MI, but too much uncertainty exists regarding morning storms to introduce them at them at this time. ...Florida... Latest forecast from the National Hurricane Center shows Hurricane Dorian should remain just offshore the east coast of the FL Peninsula today through tonight. However, low-level convergence and banded convection within the western half of the system will spread slowly northward. While tornadoes are generally not favored along the west side of the track, effective SRH around 200 m2/s2 during the day increasing to over 300 m2/s2 into early Wednesday morning may support a couple rotating storms with a brief/weak tornado risk. ..Gleason/Squitieri.. 09/03/2019 Read more

WW 0633 Status Updates
STATUS REPORT ON WW 633 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SE MKT TO 25 ENE MKT TO 35 NW RST TO 45 N RST TO 25 WSW EAU TO 20 NW EAU TO 30 NNW EAU TO 40 N EAU TO 55 N EAU TO 60 W RHI TO 55 NE EAU TO 45 WSW RHI. FOR ADDITIONAL INFORMATION SEE SPC MESOSCALE DISCUSSION 1919. ..EDWARDS..09/03/19 ATTN...WFO...DLH...MPX...ARX... STATUS REPORT FOR WS 633 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC037-039-045-049-053-055-109-131-147-157-169-030540- MN . MINNESOTA COUNTIES INCLUDED ARE DAKOTA DODGE FILLMORE GOODHUE HENNEPIN HOUSTON OLMSTED RICE STEELE WABASHA WINONA WIC005-011-017-019-033-035-053-063-091-093-107-119-121-030540- WI . WISCONSIN COUNTIES INCLUDED ARE BARRON BUFFALO CHIPPEWA CLARK DUNN EAU CLAIRE JACKSON LA CROSSE PEPIN PIERCE RUSK TAYLOR TREMPEALEAU Read more

WW 633 SEVERE TSTM MN WI 022355Z - 030700Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 633 NWS Storm Prediction Center Norman OK 655 PM CDT Mon Sep 2 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western, Central and Eastern Minnesota West-central Wisconsin * Effective this Monday night and Tuesday morning from 655 PM until 200 AM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 90 mph likely Isolated large hail events to 1 inch in diameter possible SUMMARY...An organized linear MCS will continue to move southeastward from west-central Minnesota into west-central Wisconsin this evening. An unstable airmass along with strong winds aloft will make conditions favorable for damaging wind gusts. A few wind gusts above 70 kt will be possible. The severe thunderstorm watch area is approximately along and 85 statute miles either side of a line from 50 miles west southwest of Brainerd MN to 40 miles north northeast of La Crosse WI. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 632... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 80 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 29040. ...Broyles Read more

MD 1919 CONCERNING SEVERE THUNDERSTORM WATCH 633... FOR PORTIONS OF SOUTHEASTERN MN...EXTREME NORTHEASTERN IA AND WESTERN/CENTRAL/SOUTHERN WI
Mesoscale Discussion 1919 NWS Storm Prediction Center Norman OK 1139 PM CDT Mon Sep 02 2019 Areas affected...portions of southeastern MN...extreme northeastern IA and western/central/southern WI Concerning...Severe Thunderstorm Watch 633... Valid 030439Z - 030645Z The severe weather threat for Severe Thunderstorm Watch 633 continues. SUMMARY...Localized potential remains for severe gusts, isolated hail, and brief tornado with a quasi-linear MCS that continues to move southeastward 40-50 kt across the remainder of the watch area. Watch 633 may continue to be cleared in its wake. Convective trends will be monitored to assess potential for WW 633 local extension and/or new watch possibilities farther southeast into more of WI, though uncertainty is growing on those courses of action, given recent overall weakening trends and mixed signals on instability over southern WI. DISCUSSION...As of 430Z, the strongest part of the MCS appeared as a broken arc of high reflectivity with somewhat ragged structure on its front and rear portions, extending from parts of Washburn/Sawyer Counties WI across Dunn County to portions of Rice/Waseca Counties in MN. An embedded mesocirculation apparently produced a brief tornado -- around 310Z in western Hennepin County. The southern part of the complex has been interacting with a near-surface warm front that extended east-southeastward over south-central WI to southern Lake Michigan. The complex should proceed east-southeastward to southeastward astride the associated buoyancy/theta-e gradient into central/southern WI, with strongest recent velocities around 2 km AGL noted in the rear-inflow region of the Dunn County segment, north of the surface warm front. An axis of relatively maximized effective SRH will remain along and north of the surface warm front, but lessening eastward. Objective analyses, modified RAOBs and VWP data indicate that low-level shear/SRH will continue to decrease with eastward extent across southern WI -- as will buoyancy. A pocket of relatively maximized MLCAPE (around 1500 J/kg) and little to no MLCINH is evident over southwestern WI from the MN border east-southeastward to near MSN, with considerable decrease in low-level theta-e, lapse rates and CAPE apparent farther east. ..Edwards.. 09/03/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...MKX...DLH...ARX...MPX... LAT...LON 44199368 44249315 44499252 44829196 45149181 45479165 45709162 45569058 45268994 44488936 43908895 43588858 43128859 42798881 42608940 42569037 42879104 43299177 43909320 44159368 44199368 Read more

WW 0633 Status Updates
STATUS REPORT ON WW 633 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 ESE RWF TO 35 NNW MKT TO 25 WSW MSP TO 5 NW MSP TO 35 NNE MSP TO 50 NNE MSP TO 65 ENE STC TO 65 ENE STC TO 40 SSW ASX. FOR ADDITIONAL INFORMATION SEE SPC MESOSCALE DISCUSSION 1918. ..EDWARDS..09/03/19 ATTN...WFO...DLH...MPX...ARX... STATUS REPORT FOR WS 633 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC003-019-025-037-039-045-049-055-079-103-109-123-131-139-143- 147-157-163-169-030440- MN . MINNESOTA COUNTIES INCLUDED ARE ANOKA CARVER CHISAGO DAKOTA DODGE FILLMORE GOODHUE HOUSTON LE SUEUR NICOLLET OLMSTED RAMSEY RICE SCOTT SIBLEY STEELE WABASHA WASHINGTON WINONA WIC005-011-013-017-019-033-035-053-063-091-093-095-107-109-119- 121-129-030440- WI . WISCONSIN COUNTIES INCLUDED ARE BARRON BUFFALO BURNETT Read more

WW 0633 Status Updates
STATUS REPORT ON WW 633 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 ESE VVV TO 30 N RWF TO 30 SW STC TO 15 W STC TO 25 SSE BRD TO 30 ESE BRD TO 40 E BRD TO 40 SSW DLH TO 45 S DLH TO 45 SW ASX. FOR ADDITIONAL INFORMATION SEE SPC MESOSCALE DISCUSSION 1918. ..EDWARDS..09/03/19 ATTN...WFO...DLH...MPX...ARX... STATUS REPORT FOR WS 633 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC001-003-009-019-025-037-039-045-049-053-055-059-065-067-079- 085-093-095-097-103-109-115-123-129-131-139-141-143-145-147-157- 163-169-171-030340- MN . MINNESOTA COUNTIES INCLUDED ARE AITKIN ANOKA BENTON CARVER CHISAGO DAKOTA DODGE FILLMORE GOODHUE HENNEPIN HOUSTON ISANTI KANABEC KANDIYOHI LE SUEUR MCLEOD MEEKER MILLE LACS MORRISON NICOLLET OLMSTED PINE RAMSEY RENVILLE RICE SCOTT SHERBURNE SIBLEY STEARNS STEELE WABASHA WASHINGTON WINONA WRIGHT WIC005-011-013-017-019-033-035-053-063-091-093-095-107-109-119- Read more

MD 1918 CONCERNING SEVERE THUNDERSTORM WATCH 633... FOR PORTIONS OF SOUTH-CENTRAL/SOUTHEASTERN MN.
Mesoscale Discussion 1918 NWS Storm Prediction Center Norman OK 0932 PM CDT Mon Sep 02 2019 Areas affected...portions of south-central/southeastern MN. Concerning...Severe Thunderstorm Watch 633... Valid 030232Z - 030400Z The severe weather threat for Severe Thunderstorm Watch 633 continues. SUMMARY...A relatively maximized channel of severe wind and hail, along with the potential for an embedded tornado, exists in that part of the MCS crossing portions of Meeker County as of 230Z. This segment with a well-defined mesovortex and rear-inflow jet projects southeastward to portions of the Twin Cities metro between 03-04Z. More broadly, the watch should be maintained ahead of the main MCS and still can be cleared in its immediate wake. DISCUSSION...The sporadically bowing MCS that has produced several reports of severe wind, despite moving atop a relatively stable near-surface layer across parts of ND and western MN, is moving southeastward at 45-50 kt. This track takes the complex obliquely into a more-favorable, more-unstable thermodynamic regime closer to the surface warm front, with is analyzed roughly 40-50 nm north of the MN/IA line. The modified 00Z MPX RAOB yields 1000-2000 J/kg MUCAPE, waning with distance north of the warm front. 45-60-kt effective-shear vectors remain aligned parallel to the baroclinic zone, augmenting the rear-inflow jet and its potential to persist (and perhaps enlarge). Relatively backed and strong flow is evident in the MPX VWP (e.g., 35-kt southerlies at 850 mb), contributing to both favorable storm-relative winds in the inflow layer, and enlarged hodographs with 300-500 J/kg effective SRH. Lowest-layer inflow parcels downshear appear close to surface-based, even without accounting for lift due to internal/storm-scale forcing. As such, in the channel described above, any deep/sustained mesovortex will offer a tornado threat in addition to severe nontornadic wind and sporadic large hail. ..Edwards.. 09/03/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX... LAT...LON 45049472 45319457 45249401 44929309 44689283 44549340 44849425 45049472 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0846 PM CDT Mon Sep 02 2019 Valid 030100Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL MN AND WEST-CENTRAL WI... ...SUMMARY... Severe thunderstorms capable of producing mainly damaging winds will continue across parts of the Upper Midwest through early Tuesday morning, with the most likely corridor from west-central into southern Minnesota and west-central Wisconsin. A low tornado risk will also continue through the overnight hours along parts of the Florida east coast in association with Hurricane Dorian. ...Northern Plains/Upper Midwest... A small but well organized bow echo that produced multiple measured severe wind gusts across central/eastern ND earlier this afternoon will continue southeastward into parts of the Upper Midwest this evening and overnight. Greater surface-based instability will likely remain displaced to the south of this line of storms. Even so, a 40-50+ kt south-southwesterly low-level jet and strengthening winds in the 700-500 mb layer associated with a shortwave trough moving eastward over the northern Plains will likely support continued storm organization and intensity tonight. Given the linear storm mode, severe winds will likely remain the primary threat, with the greatest damaging wind threat across parts of southern/central MN into west-central WI along an instability gradient. Isolated significant severe wind gusts of 65+ kt may occur in this corridor given the strength of the low and mid-level winds. A tornado or two will also remain possible, particularly if the southern flank of the line can ingest more buoyant low-level air near/just north of a surface warm front. ...Northeast/Mid-Atlantic... Isolated strong to severe thunderstorms that developed earlier today across parts of the Northeast and Mid-Atlantic ahead of a surface cold front should continue to weaken this evening with the loss of daytime heating. However, occasional strong/gusty downdraft winds associated with these storms may remain possible in the short term (next 1-2 hours) as 35-40 kt of mid-level flow and similar values of effective bulk shear remain over this region. ...Florida Atlantic Coast... Hurricane Dorian is forecast by the National Hurricane Center to move slowly west-northwestward through early Tuesday morning. Dorian will likely remain far enough offshore to limit the overall tornado threat. Still, low-level hodographs should gain some additional length/curvature overnight as winds strengthen along the east coast of the FL Peninsula. Any low-topped cells that can develop in outer convective rainbands might pose a risk for a brief tornado. ..Gleason.. 09/03/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0846 PM CDT Mon Sep 02 2019 Valid 030100Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL MN AND WEST-CENTRAL WI... ...SUMMARY... Severe thunderstorms capable of producing mainly damaging winds will continue across parts of the Upper Midwest through early Tuesday morning, with the most likely corridor from west-central into southern Minnesota and west-central Wisconsin. A low tornado risk will also continue through the overnight hours along parts of the Florida east coast in association with Hurricane Dorian. ...Northern Plains/Upper Midwest... A small but well organized bow echo that produced multiple measured severe wind gusts across central/eastern ND earlier this afternoon will continue southeastward into parts of the Upper Midwest this evening and overnight. Greater surface-based instability will likely remain displaced to the south of this line of storms. Even so, a 40-50+ kt south-southwesterly low-level jet and strengthening winds in the 700-500 mb layer associated with a shortwave trough moving eastward over the northern Plains will likely support continued storm organization and intensity tonight. Given the linear storm mode, severe winds will likely remain the primary threat, with the greatest damaging wind threat across parts of southern/central MN into west-central WI along an instability gradient. Isolated significant severe wind gusts of 65+ kt may occur in this corridor given the strength of the low and mid-level winds. A tornado or two will also remain possible, particularly if the southern flank of the line can ingest more buoyant low-level air near/just north of a surface warm front. ...Northeast/Mid-Atlantic... Isolated strong to severe thunderstorms that developed earlier today across parts of the Northeast and Mid-Atlantic ahead of a surface cold front should continue to weaken this evening with the loss of daytime heating. However, occasional strong/gusty downdraft winds associated with these storms may remain possible in the short term (next 1-2 hours) as 35-40 kt of mid-level flow and similar values of effective bulk shear remain over this region. ...Florida Atlantic Coast... Hurricane Dorian is forecast by the National Hurricane Center to move slowly west-northwestward through early Tuesday morning. Dorian will likely remain far enough offshore to limit the overall tornado threat. Still, low-level hodographs should gain some additional length/curvature overnight as winds strengthen along the east coast of the FL Peninsula. Any low-topped cells that can develop in outer convective rainbands might pose a risk for a brief tornado. ..Gleason.. 09/03/2019 Read more