Severe Storms

WW 0577 Status Updates
STATUS REPORT ON WW 577 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 NNE AKO TO 10 N MCK. ..SMITH..08/13/19 ATTN...WFO...GLD...BOU...LBF... STATUS REPORT FOR WT 577 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-063-073-121-125-132240- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIT CARSON LINCOLN WASHINGTON YUMA KSC023-039-063-065-071-109-137-153-179-181-193-199-203-132240- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GOVE GRAHAM GREELEY LOGAN NORTON RAWLINS SHERIDAN SHERMAN THOMAS WALLACE WICHITA NEC057-087-145-132240- NE . NEBRASKA COUNTIES INCLUDED ARE Read more

WW 0576 Status Updates
STATUS REPORT ON WW 576 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 SW GSP TO 20 S AVL TO 10 SSE HKY TO 30 SW GSO TO 30 ESE GSO TO 25 NNE RDU. ..COOK..08/13/19 ATTN...WFO...GSP...RAH...RNK...MRX... STATUS REPORT FOR WS 576 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NCC001-025-035-045-057-071-097-109-119-151-159-132240- NC . NORTH CAROLINA COUNTIES INCLUDED ARE ALAMANCE CABARRUS CATAWBA CLEVELAND DAVIDSON GASTON IREDELL LINCOLN MECKLENBURG RANDOLPH ROWAN SCC021-045-083-091-132240- SC . SOUTH CAROLINA COUNTIES INCLUDED ARE CHEROKEE GREENVILLE SPARTANBURG YORK THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 576 SEVERE TSTM GA NC SC TN VA 131725Z - 132300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 576 NWS Storm Prediction Center Norman OK 125 PM EDT Tue Aug 13 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far northeast Georgia Western North Carolina Far northwest South Carolina Far eastern Tennessee Southwest Virginia * Effective this Tuesday afternoon and evening from 125 PM until 700 PM EDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible SUMMARY...A line of strong to locally severe storms across southwest Virginia and eastern Tennessee may intensify after it crosses the crest of the southern Appalachians, with additional clusters possibly developing downstream through the afternoon. The severe thunderstorm watch area is approximately along and 90 statute miles east and west of a line from 30 miles west southwest of Greenville SC to 60 miles northwest of Danville VA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27025. ...Grams Read more

WW 0578 Status Updates
STATUS REPORT ON WW 578 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 ESE GSO TO 25 NNE RDU TO 15 NE RZZ TO 30 NE RZZ TO 15 SW RIC. ..COOK..08/13/19 ATTN...WFO...RAH...AKQ... STATUS REPORT FOR WS 578 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NCC007-037-051-063-065-069-073-077-083-085-091-093-101-105-123- 125-127-131-135-153-163-165-167-181-183-185-191-195-132240- NC . NORTH CAROLINA COUNTIES INCLUDED ARE ANSON CHATHAM CUMBERLAND DURHAM EDGECOMBE FRANKLIN GATES GRANVILLE HALIFAX HARNETT HERTFORD HOKE JOHNSTON LEE MONTGOMERY MOORE NASH NORTHAMPTON ORANGE RICHMOND SAMPSON SCOTLAND STANLY VANCE WAKE WARREN WAYNE WILSON VAC093-149-175-181-183-199-550-620-650-670-700-710-735-740-800- 810-132240- VA . VIRGINIA COUNTIES INCLUDED ARE ISLE OF WIGHT PRINCE GEORGE SOUTHAMPTON Read more

WW 0579 Status Updates
STATUS REPORT ON WW 579 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..COOK..08/13/19 ATTN...WFO...OHX...MRX...HUN... STATUS REPORT FOR WS 579 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TNC003-007-011-015-021-027-031-035-037-041-043-049-051-055-061- 065-081-085-087-099-101-103-105-107-111-115-117-119-121-123-127- 129-133-135-137-139-141-143-145-147-149-153-159-165-169-175-177- 181-185-187-189-132240- TN . TENNESSEE COUNTIES INCLUDED ARE BEDFORD BLEDSOE BRADLEY CANNON CHEATHAM CLAY COFFEE CUMBERLAND DAVIDSON DE KALB DICKSON FENTRESS FRANKLIN GILES GRUNDY HAMILTON HICKMAN HUMPHREYS JACKSON LAWRENCE LEWIS LINCOLN LOUDON MCMINN MACON MARION MARSHALL MAURY MEIGS MONROE MOORE MORGAN OVERTON PERRY PICKETT POLK PUTNAM RHEA ROANE ROBERTSON RUTHERFORD SEQUATCHIE SMITH SUMNER TROUSDALE VAN BUREN WARREN WAYNE WHITE WILLIAMSON WILSON Read more

WW 0578 Status Updates
STATUS REPORT ON WW 578 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1728 ..GLEASON..08/13/19 ATTN...WFO...RAH...AKQ... STATUS REPORT FOR WS 578 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NCC007-037-051-063-065-069-073-077-083-085-091-093-101-105-123- 125-127-131-135-153-163-165-167-181-183-185-191-195-132140- NC . NORTH CAROLINA COUNTIES INCLUDED ARE ANSON CHATHAM CUMBERLAND DURHAM EDGECOMBE FRANKLIN GATES GRANVILLE HALIFAX HARNETT HERTFORD HOKE JOHNSTON LEE MONTGOMERY MOORE NASH NORTHAMPTON ORANGE RICHMOND SAMPSON SCOTLAND STANLY VANCE WAKE WARREN WAYNE WILSON VAC025-053-081-093-111-117-149-175-181-183-199-550-595-620-650- 670-700-710-735-740-800-810-132140- VA . VIRGINIA COUNTIES INCLUDED ARE Read more

WW 0576 Status Updates
STATUS REPORT ON WW 576 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 ENE AND TO 20 S AVL TO 10 SE HKY TO 25 ENE HKY TO 20 WSW AVC. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1728 ..GLEASON..08/13/19 ATTN...WFO...GSP...RAH...RNK...MRX... STATUS REPORT FOR WS 576 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NCC001-025-033-035-045-057-059-067-071-081-097-109-119-145-151- 159-132140- NC . NORTH CAROLINA COUNTIES INCLUDED ARE ALAMANCE CABARRUS CASWELL CATAWBA CLEVELAND DAVIDSON DAVIE FORSYTH GASTON GUILFORD IREDELL LINCOLN MECKLENBURG PERSON RANDOLPH ROWAN SCC021-045-083-091-132140- SC . SOUTH CAROLINA COUNTIES INCLUDED ARE CHEROKEE GREENVILLE SPARTANBURG YORK Read more

MD 1728 CONCERNING SEVERE THUNDERSTORM WATCH 576...578... FOR PORTIONS OF SOUTH-CENTRAL/SOUTHEASTERN VA...MUCH OF NC...AND FAR NORTHERN SC
Mesoscale Discussion 1728 NWS Storm Prediction Center Norman OK 0330 PM CDT Tue Aug 13 2019 Areas affected...Portions of south-central/southeastern VA...much of NC...and far northern SC Concerning...Severe Thunderstorm Watch 576...578... Valid 132030Z - 132130Z The severe weather threat for Severe Thunderstorm Watch 576, 578 continues. SUMMARY...Scattered strong/gusty winds should continue to produce damage through the early evening across Severe Thunderstorm Watch 576 and 578. DISCUSSION...A loosely organized line of storms has recently crossed the Appalachians into parts of western/central NC and south-central VA. 30-40 kt of mid-level flow remains generally confined to portions of southern VA where instability is slightly weaker compared to locations farther south. Regardless, low-level lapse rates have been able to steepen ahead of ongoing convection owing to strong diurnal heating. Multiple tree damage reports have been received over the past few hours, and this threat should continue with eastward extent across central NC into southeastern VA through the early evening. Storms that can become oriented more orthogonal to the mean westerly flow should have a greater damaging wind potential. This wind threat may be maximized across north-central NC and southeastern VA in the short term based on radar trends. ..Gleason.. 08/13/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...RAH...RNK...CAE...GSP... LAT...LON 34858205 35848122 36278020 36577876 37317812 37467685 37277600 36607600 35027844 34927987 34858205 Read more

WW 0577 Status Updates
STATUS REPORT ON WW 577 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 NE AKO TO 35 SSE SNY TO 30 ESE SNY TO 15 NNW LBF. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1727 ..MOSIER..08/13/19 ATTN...WFO...GLD...BOU...LBF... STATUS REPORT FOR WT 577 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-063-073-095-115-121-125-132140- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIT CARSON LINCOLN PHILLIPS SEDGWICK WASHINGTON YUMA KSC023-039-063-065-071-109-137-153-179-181-193-199-203-132140- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GOVE GRAHAM GREELEY LOGAN NORTON RAWLINS SHERIDAN SHERMAN THOMAS WALLACE WICHITA NEC029-057-063-085-087-111-135-145-132140- Read more

MD 1727 CONCERNING TORNADO WATCH 577... FOR SOUTHWEST NE...NORTHEAST CO...NORTHWEST KS
Mesoscale Discussion 1727 NWS Storm Prediction Center Norman OK 0304 PM CDT Tue Aug 13 2019 Areas affected...Southwest NE...Northeast CO...Northwest KS Concerning...Tornado Watch 577... Valid 132004Z - 132130Z The severe weather threat for Tornado Watch 577 continues. SUMMARY...Threat for all severe hazards, including very large hail greater than 2" in diameter and tornadoes, continues across Tornado Watch 577. DISCUSSION...Radar signature within the storm over Perkins County NE suggests it has become more outflow dominant, although it still possesses a very strong updraft. This upscale growth/linear transition is expected to continue, gradually transitioning the primary severe threat from very large hail (i.e. greater than 2" in diameter) to strong wind gusts. Currently, all severe hazards, including a tornado or two, still remain possible with this storm. Farther southwest, a few discrete supercells have developed. Strong instability, southeasterly low-level flow, and ample low-level moisture suggests these storms will persist, posing a threat for all severe hazards, including brief tornadoes. ..Mosier.. 08/13/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...DDC...GLD...PUB...BOU... LAT...LON 38440228 38500352 38980400 40300281 40850244 41390181 41370060 40520019 38800056 38440228 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2019 Valid 132000Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY EASTWARD TO THE ATLANTIC SEABOARD... ...SUMMARY... Significant severe hail and wind gusts are possible across the central High Plains during the late afternoon to mid evening. Scattered damaging winds are possible from the Tennessee Valley to the Carolinas and southern Virginia through early evening. ...DISCUSSION... The main change to the outlook is to reorient the enhanced risk area in the central High Plains. The enhanced has been shifted eastward and now goes from southwest Nebraska and far northeastern Colorado into southwest Kansas which is aligned with the projected track of ongoing severe thunderstorms. The hail and wind damage probabilities have been changed according to the updated position of the enhanced risk area. Severe weather probabilities have been removed from parts of the central and northern High Plains to the north and northeast of the ongoing convection. ..Broyles.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1129 AM CDT Tue Aug 13 2019/ ...Central High Plains... Weak warm-advection driven convection is ongoing across northwest/north-central NE. To its south, ample low-level moisture is prevalent. The difference between the NAM/RAP in the degree of boundary-layer mixing within the warm/moist sector is unusual in that the NAM is actually quite a bit more mixed at peak heating than the RAP (typically its the reverse). Surface dew points will probably mix to 60-65 F, contributing to a confined corridor of MLCAPE of 2000-3000 J/kg across the CO/KS/NE border area beneath rather steep mid-level lapse rates. Surface-based storm development is expected around 21Z near this tri-state region as convergence strengthens at the intersection of the lee trough and the southward-sagging cold front. Initial storms will likely be discrete supercells capable of producing isolated very large hail and perhaps a tornado or two. Convection should grow upscale into a southward propagating cluster into a weak nocturnal low-level jet across far eastern CO/western KS, with a continuing threat for severe wind gusts into early tonight. ...TN Valley to the Carolinas/southern VA... A separated belt of enhanced 700-mb westerlies should remain centered on the KY to VA area through early evening. Areas of decaying stratiform rain remnants of early morning MCSs are generally located within this belt of stronger flow, largely south of 12Z HREF members. Convection is ongoing an arc across eastern TN into far southwest VA along the remnant outflow. Ample heating is occurring downstream across the Carolinas and it is possible that this convection intensifies (see MCD 1722). With flow weakening with southern extent, the degree of organization becomes increasingly uncertain, but at least a few multicell clusters should develop with a risk for scattered damaging winds across southern Virginia and parts of the Carolinas. Additional clusters should also form west across the TN Valley along the remnant outflow towards late afternoon as large buoyancy develops amid upper 70s surface dew points. Somewhat weaker effective shear from 15-25 kt should foster multicell clusters with a risk for isolated to scattered damaging winds. ...Upper MS Valley... A shortwave trough along the Red River Valley should dampen as it tracks into WI tonight. Ascent preceding this trough will coincide with a pocket of stronger surface heating and low-level convergence along a weak northwest-southeast oriented front, which will support scattered thunderstorm development towards late afternoon. A confined corridor of MLCAPE from 1000-1500 J/kg may potentially coincide with effective bulk shear near 40 kt. However, modest mid-level lapse rates should temper overall storm intensity despite the expectation of a few transient supercells. Isolated damaging winds and severe hail will likely be the main threats. A brief tornado may also occur with storms moving southeast along the boundary, where low-level shear and vertical vorticity will be larger. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2019 Valid 132000Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY EASTWARD TO THE ATLANTIC SEABOARD... ...SUMMARY... Significant severe hail and wind gusts are possible across the central High Plains during the late afternoon to mid evening. Scattered damaging winds are possible from the Tennessee Valley to the Carolinas and southern Virginia through early evening. ...DISCUSSION... The main change to the outlook is to reorient the enhanced risk area in the central High Plains. The enhanced has been shifted eastward and now goes from southwest Nebraska and far northeastern Colorado into southwest Kansas which is aligned with the projected track of ongoing severe thunderstorms. The hail and wind damage probabilities have been changed according to the updated position of the enhanced risk area. Severe weather probabilities have been removed from parts of the central and northern High Plains to the north and northeast of the ongoing convection. ..Broyles.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1129 AM CDT Tue Aug 13 2019/ ...Central High Plains... Weak warm-advection driven convection is ongoing across northwest/north-central NE. To its south, ample low-level moisture is prevalent. The difference between the NAM/RAP in the degree of boundary-layer mixing within the warm/moist sector is unusual in that the NAM is actually quite a bit more mixed at peak heating than the RAP (typically its the reverse). Surface dew points will probably mix to 60-65 F, contributing to a confined corridor of MLCAPE of 2000-3000 J/kg across the CO/KS/NE border area beneath rather steep mid-level lapse rates. Surface-based storm development is expected around 21Z near this tri-state region as convergence strengthens at the intersection of the lee trough and the southward-sagging cold front. Initial storms will likely be discrete supercells capable of producing isolated very large hail and perhaps a tornado or two. Convection should grow upscale into a southward propagating cluster into a weak nocturnal low-level jet across far eastern CO/western KS, with a continuing threat for severe wind gusts into early tonight. ...TN Valley to the Carolinas/southern VA... A separated belt of enhanced 700-mb westerlies should remain centered on the KY to VA area through early evening. Areas of decaying stratiform rain remnants of early morning MCSs are generally located within this belt of stronger flow, largely south of 12Z HREF members. Convection is ongoing an arc across eastern TN into far southwest VA along the remnant outflow. Ample heating is occurring downstream across the Carolinas and it is possible that this convection intensifies (see MCD 1722). With flow weakening with southern extent, the degree of organization becomes increasingly uncertain, but at least a few multicell clusters should develop with a risk for scattered damaging winds across southern Virginia and parts of the Carolinas. Additional clusters should also form west across the TN Valley along the remnant outflow towards late afternoon as large buoyancy develops amid upper 70s surface dew points. Somewhat weaker effective shear from 15-25 kt should foster multicell clusters with a risk for isolated to scattered damaging winds. ...Upper MS Valley... A shortwave trough along the Red River Valley should dampen as it tracks into WI tonight. Ascent preceding this trough will coincide with a pocket of stronger surface heating and low-level convergence along a weak northwest-southeast oriented front, which will support scattered thunderstorm development towards late afternoon. A confined corridor of MLCAPE from 1000-1500 J/kg may potentially coincide with effective bulk shear near 40 kt. However, modest mid-level lapse rates should temper overall storm intensity despite the expectation of a few transient supercells. Isolated damaging winds and severe hail will likely be the main threats. A brief tornado may also occur with storms moving southeast along the boundary, where low-level shear and vertical vorticity will be larger. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2019 Valid 132000Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY EASTWARD TO THE ATLANTIC SEABOARD... ...SUMMARY... Significant severe hail and wind gusts are possible across the central High Plains during the late afternoon to mid evening. Scattered damaging winds are possible from the Tennessee Valley to the Carolinas and southern Virginia through early evening. ...DISCUSSION... The main change to the outlook is to reorient the enhanced risk area in the central High Plains. The enhanced has been shifted eastward and now goes from southwest Nebraska and far northeastern Colorado into southwest Kansas which is aligned with the projected track of ongoing severe thunderstorms. The hail and wind damage probabilities have been changed according to the updated position of the enhanced risk area. Severe weather probabilities have been removed from parts of the central and northern High Plains to the north and northeast of the ongoing convection. ..Broyles.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1129 AM CDT Tue Aug 13 2019/ ...Central High Plains... Weak warm-advection driven convection is ongoing across northwest/north-central NE. To its south, ample low-level moisture is prevalent. The difference between the NAM/RAP in the degree of boundary-layer mixing within the warm/moist sector is unusual in that the NAM is actually quite a bit more mixed at peak heating than the RAP (typically its the reverse). Surface dew points will probably mix to 60-65 F, contributing to a confined corridor of MLCAPE of 2000-3000 J/kg across the CO/KS/NE border area beneath rather steep mid-level lapse rates. Surface-based storm development is expected around 21Z near this tri-state region as convergence strengthens at the intersection of the lee trough and the southward-sagging cold front. Initial storms will likely be discrete supercells capable of producing isolated very large hail and perhaps a tornado or two. Convection should grow upscale into a southward propagating cluster into a weak nocturnal low-level jet across far eastern CO/western KS, with a continuing threat for severe wind gusts into early tonight. ...TN Valley to the Carolinas/southern VA... A separated belt of enhanced 700-mb westerlies should remain centered on the KY to VA area through early evening. Areas of decaying stratiform rain remnants of early morning MCSs are generally located within this belt of stronger flow, largely south of 12Z HREF members. Convection is ongoing an arc across eastern TN into far southwest VA along the remnant outflow. Ample heating is occurring downstream across the Carolinas and it is possible that this convection intensifies (see MCD 1722). With flow weakening with southern extent, the degree of organization becomes increasingly uncertain, but at least a few multicell clusters should develop with a risk for scattered damaging winds across southern Virginia and parts of the Carolinas. Additional clusters should also form west across the TN Valley along the remnant outflow towards late afternoon as large buoyancy develops amid upper 70s surface dew points. Somewhat weaker effective shear from 15-25 kt should foster multicell clusters with a risk for isolated to scattered damaging winds. ...Upper MS Valley... A shortwave trough along the Red River Valley should dampen as it tracks into WI tonight. Ascent preceding this trough will coincide with a pocket of stronger surface heating and low-level convergence along a weak northwest-southeast oriented front, which will support scattered thunderstorm development towards late afternoon. A confined corridor of MLCAPE from 1000-1500 J/kg may potentially coincide with effective bulk shear near 40 kt. However, modest mid-level lapse rates should temper overall storm intensity despite the expectation of a few transient supercells. Isolated damaging winds and severe hail will likely be the main threats. A brief tornado may also occur with storms moving southeast along the boundary, where low-level shear and vertical vorticity will be larger. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 13 2019 Valid 132000Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY EASTWARD TO THE ATLANTIC SEABOARD... ...SUMMARY... Significant severe hail and wind gusts are possible across the central High Plains during the late afternoon to mid evening. Scattered damaging winds are possible from the Tennessee Valley to the Carolinas and southern Virginia through early evening. ...DISCUSSION... The main change to the outlook is to reorient the enhanced risk area in the central High Plains. The enhanced has been shifted eastward and now goes from southwest Nebraska and far northeastern Colorado into southwest Kansas which is aligned with the projected track of ongoing severe thunderstorms. The hail and wind damage probabilities have been changed according to the updated position of the enhanced risk area. Severe weather probabilities have been removed from parts of the central and northern High Plains to the north and northeast of the ongoing convection. ..Broyles.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1129 AM CDT Tue Aug 13 2019/ ...Central High Plains... Weak warm-advection driven convection is ongoing across northwest/north-central NE. To its south, ample low-level moisture is prevalent. The difference between the NAM/RAP in the degree of boundary-layer mixing within the warm/moist sector is unusual in that the NAM is actually quite a bit more mixed at peak heating than the RAP (typically its the reverse). Surface dew points will probably mix to 60-65 F, contributing to a confined corridor of MLCAPE of 2000-3000 J/kg across the CO/KS/NE border area beneath rather steep mid-level lapse rates. Surface-based storm development is expected around 21Z near this tri-state region as convergence strengthens at the intersection of the lee trough and the southward-sagging cold front. Initial storms will likely be discrete supercells capable of producing isolated very large hail and perhaps a tornado or two. Convection should grow upscale into a southward propagating cluster into a weak nocturnal low-level jet across far eastern CO/western KS, with a continuing threat for severe wind gusts into early tonight. ...TN Valley to the Carolinas/southern VA... A separated belt of enhanced 700-mb westerlies should remain centered on the KY to VA area through early evening. Areas of decaying stratiform rain remnants of early morning MCSs are generally located within this belt of stronger flow, largely south of 12Z HREF members. Convection is ongoing an arc across eastern TN into far southwest VA along the remnant outflow. Ample heating is occurring downstream across the Carolinas and it is possible that this convection intensifies (see MCD 1722). With flow weakening with southern extent, the degree of organization becomes increasingly uncertain, but at least a few multicell clusters should develop with a risk for scattered damaging winds across southern Virginia and parts of the Carolinas. Additional clusters should also form west across the TN Valley along the remnant outflow towards late afternoon as large buoyancy develops amid upper 70s surface dew points. Somewhat weaker effective shear from 15-25 kt should foster multicell clusters with a risk for isolated to scattered damaging winds. ...Upper MS Valley... A shortwave trough along the Red River Valley should dampen as it tracks into WI tonight. Ascent preceding this trough will coincide with a pocket of stronger surface heating and low-level convergence along a weak northwest-southeast oriented front, which will support scattered thunderstorm development towards late afternoon. A confined corridor of MLCAPE from 1000-1500 J/kg may potentially coincide with effective bulk shear near 40 kt. However, modest mid-level lapse rates should temper overall storm intensity despite the expectation of a few transient supercells. Isolated damaging winds and severe hail will likely be the main threats. A brief tornado may also occur with storms moving southeast along the boundary, where low-level shear and vertical vorticity will be larger. Read more

WW 0579 Status Updates
STATUS FOR WATCH 0579 HAS NOT BEEN ISSUED YET Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Tue Aug 13 2019 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... As modest flow aloft overspreads a well-mixed boundary layer, locally elevated surface wind/RH conditions may occur across terrain favoring areas from the Snake River Plain in eastern Idaho, to the Great Divide basin in central/southern Wyoming. The localized nature of the elevated conditions precludes a delineation at this time. Otherwise, the previous forecast remains on track (see below for more details). ..Squitieri.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1208 AM CDT Tue Aug 13 2019/ ...Synopsis... The mid/upper synoptic pattern will amplify slightly as a broad trough becomes established across the East and a weak ridge increases across the Southwest. Stronger flow aloft will remain displaced from dry areas across the West (where fuels are cured), and this should keep fire weather concerns minimal throughout the forecast period. ...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 0224 PM CDT Tue Aug 13 2019 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... As modest flow aloft overspreads a well-mixed boundary layer, locally elevated surface wind/RH conditions may occur across terrain favoring areas from the Snake River Plain in eastern Idaho, to the Great Divide basin in central/southern Wyoming. The localized nature of the elevated conditions precludes a delineation at this time. Otherwise, the previous forecast remains on track (see below for more details). ..Squitieri.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1208 AM CDT Tue Aug 13 2019/ ...Synopsis... The mid/upper synoptic pattern will amplify slightly as a broad trough becomes established across the East and a weak ridge increases across the Southwest. Stronger flow aloft will remain displaced from dry areas across the West (where fuels are cured), and this should keep fire weather concerns minimal throughout the forecast period. ...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 0224 PM CDT Tue Aug 13 2019 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... As modest flow aloft overspreads a well-mixed boundary layer, locally elevated surface wind/RH conditions may occur across terrain favoring areas from the Snake River Plain in eastern Idaho, to the Great Divide basin in central/southern Wyoming. The localized nature of the elevated conditions precludes a delineation at this time. Otherwise, the previous forecast remains on track (see below for more details). ..Squitieri.. 08/13/2019 .PREV DISCUSSION... /ISSUED 1208 AM CDT Tue Aug 13 2019/ ...Synopsis... The mid/upper synoptic pattern will amplify slightly as a broad trough becomes established across the East and a weak ridge increases across the Southwest. Stronger flow aloft will remain displaced from dry areas across the West (where fuels are cured), and this should keep fire weather concerns minimal throughout the forecast period. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0578 Status Updates
STATUS FOR WATCH 0578 HAS NOT BEEN ISSUED YET Read more

MD 1725 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF MIDDLE/EASTERN TN
Mesoscale Discussion 1725 NWS Storm Prediction Center Norman OK 0158 PM CDT Tue Aug 13 2019 Areas affected...Portions of middle/eastern TN Concerning...Severe potential...Watch possible Valid 131858Z - 132100Z Probability of Watch Issuance...40 percent SUMMARY...An isolated damaging wind and large hail threat may increase this afternoon. Watch issuance is possible. DISCUSSION...Substantial destabilization has occurred this afternoon along/south of an outflow boundary extending northwest-southeast across middle/eastern TN. Isolated thunderstorms have persisted for the past couple of hours along this boundary about 50-55 miles south-southeast of Nashville TN. Additional convective development appears likely across middle/eastern TN this afternoon as modest ascent associated with a weak vorticity maximum over KY overspreads this region. MLCAPE of 2000-3500 J/kg will support robust updraft accelerations, and the potential for isolated damaging winds with convective downdrafts will exist as storms move generally east-southeastward. Marginally severe hail may also occur given the strong instability present. Primary uncertainty regarding a greater severe weather threat is the strength of mid-level winds and related potential for storm organization. Somewhat stronger westerly flow is being estimated by VWPs across KY compared to TN, but around 30-35 kt is present around 3-4 km AGL in the KHPX and KOHX VWPs. This may be enough to encourage some clustering of cells, with a small bowing line segment possibly developing with southeastward extent in parts of middle/eastern TN. Watch issuance may be needed later this afternoon (by 21Z/4 PM CDT). ..Gleason/Grams.. 08/13/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MRX...OHX...HUN...MEG... LAT...LON 36188789 36618702 36628593 36438488 36248449 35758479 35358520 35018585 35048811 35328826 35818819 36188789 Read more