Aggregator

000
ABPZ20 KNHC 152339
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Thu Aug 15 2019

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

An elongated area of low pressure located about 1600 miles
west-southwest of the southern tip of the Baja California peninsula
is producing a small area of disorganized showers. Environmental
conditions do not appear conducive for significant development of
this system while it moves westward at 10 to 15 mph during the next
couple of days.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent.

An area of low pressure is forecast to form south of the coasts of
El Salvador, Guatemala, and southeastern Mexico over the weekend.
Environmental conditions are expected to be conducive for gradual
development of the low while it moves slowly westward early next
week. Regardless of development, moisture associated with this
system is forecast to produce heavy rainfall and possible
flash flooding across portions of Central America through early
next week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Zelinsky/Hagen

Haines Borough stopped selling water to cruise ships on July 1 and has lost roughly $10,000 to $15,000 in revenue. Chilkat Valley News (Alaska), Aug. 8, 2019

WW 0585 Status Updates
STATUS FOR WATCH 0585 HAS NOT BEEN ISSUED YET Read more

WW 585 TORNADO KS 152310Z - 160500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 585 NWS Storm Prediction Center Norman OK 610 PM CDT Thu Aug 15 2019 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of North-central and Eastern Kansas * Effective this Thursday night from 610 PM until Midnight CDT. * Primary threats include... A couple tornadoes possible Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Severe thunderstorms are expected to develop this evening, particularly near a stalled boundary that is oriented roughly west to east across north-central/northeast Kansas. Large hail and locally damaging winds may be the most common risks, but adequate moisture and seasonally strong low-level shear supports the possibility of tornadoes, especially across northeast/east-central Kansas. The tornado watch area is approximately along and 60 statute miles north and south of a line from 55 miles west southwest of Concordia KS to 20 miles southeast of Topeka KS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and 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. && OTHER WATCH INFORMATION...CONTINUE...WW 583...WW 584... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 30025. ...Guyer Read more

WW 0583 Status Updates
STATUS REPORT ON WW 583 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 ESE 9V9 TO 5 E HON TO 30 W ATY TO 40 NNW ATY TO 65 SW FAR. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1749 ..NAUSLAR..08/15/19 ATTN...WFO...ABR...FSD... STATUS REPORT FOR WS 583 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC011-155-152340- MN . MINNESOTA COUNTIES INCLUDED ARE BIG STONE TRAVERSE SDC005-011-025-029-035-037-039-051-057-061-077-079-087-091-097- 109-111-152340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BEADLE BROOKINGS CLARK CODINGTON DAVISON DAY DEUEL GRANT HAMLIN HANSON KINGSBURY LAKE MCCOOK MARSHALL MINER ROBERTS SANBORN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE Read more

WW 583 SEVERE TSTM MN SD 152010Z - 160200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 583 NWS Storm Prediction Center Norman OK 310 PM CDT Thu Aug 15 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far west-central Minnesota Central and eastern South Dakota * Effective this Thursday afternoon and evening from 310 PM until 900 PM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2 inches in diameter possible SUMMARY...A mix of discrete cells and clusters should intensify into early evening in central South Dakota, potentially evolving into a broader linear cluster that shifts east across eastern South Dakota into perhaps far western Minnesota. The severe thunderstorm watch area is approximately along and 75 statute miles north and south of a line from 10 miles northwest of Pierre SD to 30 miles east of Watertown SD. 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27030. ...Grams Read more

MD 1749 CONCERNING SEVERE THUNDERSTORM WATCH 583... FOR EASTERN SOUTH DAKOTA AND VICINITY
Mesoscale Discussion 1749 NWS Storm Prediction Center Norman OK 0542 PM CDT Thu Aug 15 2019 Areas affected...eastern South Dakota and vicinity Concerning...Severe Thunderstorm Watch 583... Valid 152242Z - 160045Z The severe weather threat for Severe Thunderstorm Watch 583 continues. SUMMARY...The severe threat continues across eastern portions of WW583 in eastern South Dakota and vicinity. Damaging winds and large hail remain possible through 0200 UTC. DISCUSSION...A line of thunderstorms continues to move eastward across eastern South Dakota and recently produced a 66 MPH wind gust at a mesonet site in Day county. Recent radar trends from KABR show two areas where the rear inflow has strengthened in Clark and Day counties and could be foci for severe wind and a possible brief, weak tornado. Given the storm environment downstream of MLCAPE of 1000-1500 J/kg and effective bulk shear of 40-50 knots, the line of storms should continue moving eastward and maintain its intensity. Storm development and intensification on southern portion of the line may occur, especially since the instability remains favorable longer, with the hail threat being greater in this area. Even with the large-scale ascent associated with the shortwave trough moving over South Dakota, storms will begin to wane in southwest Minnesota/northwest Iowa without a low-level jet to help sustain development tonight. Storms may move outside of the watch later this evening before weakening, but a new watch is unlikely at this time. ..Nauslar/Guyer.. 08/15/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...FGF...FSD...ABR... LAT...LON 45889738 45059778 44259837 43899836 43509829 43409781 43329684 43469644 43739629 44309615 45209607 45419612 45779634 45979657 45889738 Read more

WW 0584 Status Updates
STATUS FOR WATCH 0584 HAS NOT BEEN ISSUED YET Read more

WW 0584 Status Updates
STATUS FOR WATCH 0584 HAS NOT BEEN ISSUED YET Read more

WW 584 SEVERE TSTM KS MO NE 152150Z - 160500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 584 NWS Storm Prediction Center Norman OK 450 PM CDT Thu Aug 15 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Kansas Northwest Missouri Far Southeast Nebraska * Effective this Thursday afternoon from 450 PM until Midnight CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Isolated damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Strong to severe storms should continue to develop this evening and move southeastward along and north of a prior outflow boundary. Large hail will be the primary risk with this mostly elevated storms to the north of the outflow boundary. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 30 miles southwest of Falls City NE to 55 miles east northeast of Kansas City MO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 583... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 30035. ...Guyer Read more

Soybeans in Vermillion County were short from lack of rain and were very short in Champaign County. news gazette (Champaign, Ill.), Aug. 15, 2019

WW 0583 Status Updates
STATUS REPORT ON WW 583 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 N VTN TO 30 ESE PIR TO 50 N 9V9 TO 25 SW ABR TO 50 SSE JMS. ..NAUSLAR..08/15/19 ATTN...WFO...ABR...FSD... STATUS REPORT FOR WS 583 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC011-155-152240- MN . MINNESOTA COUNTIES INCLUDED ARE BIG STONE TRAVERSE SDC003-005-011-013-015-017-025-029-035-037-039-051-057-059-061- 073-077-079-085-087-091-097-109-111-115-152240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE AURORA BEADLE BROOKINGS BROWN BRULE BUFFALO CLARK CODINGTON DAVISON DAY DEUEL GRANT HAMLIN HAND HANSON JERAULD KINGSBURY LAKE LYMAN MCCOOK MARSHALL MINER ROBERTS SANBORN SPINK Read more

MD 1748 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PORTIONS OF CENTRAL AND EASTERN KS INTO FAR WESTERN MO
Mesoscale Discussion 1748 NWS Storm Prediction Center Norman OK 0351 PM CDT Thu Aug 15 2019 Areas affected...portions of central and eastern KS into far western MO Concerning...Severe potential...Watch likely Valid 152051Z - 152245Z Probability of Watch Issuance...95 percent SUMMARY...Scattered severe storms are expected to develop over the next few hours. These storms could produce very large hail, damaging winds, and possibly a couple of tornadoes. A watch will be needed in the next 1-2 hours. DISCUSSION...Elevated convection continues this afternoon across far southeast NE into northwest MO. These storms could pose a persistent hail threat over the next several hours. An outflow boundary associated with this convection is oriented roughly west to east from near CNK in north-central KS to near Kansas City. Strong heating to the south of this boundary has resulted in around 20-30 degrees temperatures difference across the boundary, with mid 80s to near 90 degrees south and mid 60s to mid 70s north. Surface dewpoints south of the boundary ranged from the upper 60s to low 70s, resulting in 2500-3500 J/kg MLCAPE and rapidly eroding inhibition. Evidence of the weakening EML has been noted over the last 30 minutes or so in GOES-16 1-minute visible imagery as the CU field in the vicinity of the outflow boundary has showing increasing vertical development. As warm advection increases and a low level jet begins to strengthen early this evening, convection is expected to develop near the outflow boundary by 00z. Weak upper forcing will likely allow discrete cells to persist initially before upscale growth become more likely with the increasing south/southwesterly low level jet between 00-03z. Effective shear greater than 40 kt and very steep midlevel lapse rates will support supercells capable of very large hail (some baseball or larger). Damaging wind gusts (some greater than 65 kt) also appears likely given steep low level lapse rates and midlevel dryness enhancing evaporative processing leading to intense downdrafts. Somewhat more uncertain is tornado potential. Backed low level flow in the vicinity of the outflow boundary will enhanced 0-3 km SRH values. However, aforementioned downdraft potential could be a mitigating factor in overall tornado potential. Nevertheless, overall environmental parameters support at least some tornado threat with any cells that remain discrete. A watch will likely be needed for portions of the MCD area by 23z. ..Leitman/Grams.. 08/15/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SGF...EAX...TOP...ICT...GID...DDC... LAT...LON 37139517 37039599 37049687 37199770 37779863 38459895 38929893 39549872 39709849 39799751 39799601 39689548 39309455 39109429 38709410 38169419 37449447 37139517 Read more

MD 1747 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHERN VA...NC...SC...AND FAR EASTERN GA
Mesoscale Discussion 1747 NWS Storm Prediction Center Norman OK 0334 PM CDT Thu Aug 15 2019 Areas affected...Portions of southern VA...NC...SC...and far eastern GA Concerning...Severe potential...Watch unlikely Valid 152034Z - 152230Z Probability of Watch Issuance...20 percent SUMMARY...An isolated damaging wind and marginally severe hail threat should continue through the early evening. Watch issuance remains unlikely. DISCUSSION...Around 20-30 kt of mid-level southwesterly flow will remain over southern VA, the Carolinas, and far eastern GA this afternoon as weak upper-level troughing persists over much of the eastern CONUS. Scattered thunderstorms have developed this afternoon across parts of southern VA along a weak surface front. This convection initially displayed supercell characteristics, but has recently become outflow dominant per radar imagery, with strong to locally damaging winds now the main threat. Additional storms have formed along a sea breeze in coastal NC where strong instability is present, but shear is generally weaker. Current expectations are for scattered storms to continue increasing in coverage across central NC/SC along a weak stationary front. The airmass across this region remains moderately unstable, with around 2000 J/kg of MLCAPE estimated by 20Z mesoanalysis. Loosely organized multicell clusters should be the primary storm mode with southward extent across the Carolinas into far eastern GA as shear gradually decreases from north to south. Isolated damaging wind gusts will be possible as low-level lapse rates have become steepened. Marginally severe hail may also occur with transient supercells, mainly across southern VA into north-central NC where effective bulk shear is somewhat stronger. ..Gleason/Grams.. 08/15/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CHS...CAE...GSP... LAT...LON 33078208 34038152 34638095 35887924 36927916 37387871 37527711 37177629 36457592 35517631 34757679 33877840 32438035 31848121 32258185 33078208 Read more

WW 0583 Status Updates
STATUS FOR WATCH 0583 HAS NOT BEEN ISSUED YET Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Aug 15 2019 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER CENTRAL AND EASTERN KS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE NORTHERN/CENTRAL GREAT PLAINS AND THE NORTHERN MID-ATLANTIC STATES INTO PA... ...SUMMARY... Severe thunderstorms are most likely to be centered on eastern Kansas during the late afternoon and evening. Severe hail and wind gusts may be significant with a few tornadoes also possible. ...20Z Update... Overall the forecast remains on track with little change needed. Highest severe thunderstorm coverage is still expected to be across central/eastern KS later this afternoon and evening. Primary change to the outlook is to extend the Slight Risk southeastward across eastern VA and into far northeast NC. Recent trends suggest higher severe coverage across this region. ..Mosier.. 08/15/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Aug 15 2019/ ...Central/eastern KS vicinity... An MCS is ongoing across eastern NE with a trailing composite outflow/cold front extending into far northwest KS. Waning low-level warm advection through the next few hours should inhibit substantial strengthening across the Lower MS Valley. The trailing outflow will be the primary focus for late afternoon to early evening redevelopment. Low-level convergence should support initial storms from north-central into northeast KS. A plume of upper 60s surface dew points at present across central KS will be maintained as richer boundary-layer moisture advects north from OK, beneath the eastern extent of the elevated mixed layer. Ample diabatic heating will yield large buoyancy with MLCAPE likely reaching 2500-3500 J/kg. A veering wind profile with height will support initial supercells, with hodograph enlargement occurring through the evening as a southwesterly low-level jet intensifies. The setup should foster a risk for very large hail and a few tornadoes. However, the overall mode may tend to grow upscale into clusters and an MCS relatively quickly given the strengthening forcing for ascent during the evening. This may result in the predominant threat becoming severe wind gusts (a few of which may be significant) as an MCS develops bowing structures across eastern KS towards western MO/northern OK. Overall severe threat should subside overnight with the most likely MCS track approaching the Ozark Plateau. 12Z non-HRRR HREF members are more consistent with this overall scenario than recent HRRR runs, with the parent RAP maintaining more pronounced MLCIN in much of the warm sector. Nevertheless, an Enhanced Slight Risk appears warranted given the potential for a higher-end intensity/coverage scenario. ...SD vicinity... A low-amplitude shortwave trough and attendant surface boundary will move east across the Dakotas. Ample diabatic heating is underway downstream across central to eastern SD north of the NE MCS. Presence of upper 50s to low 60s boundary-layer dew points will support MLCAPE of at least 1500-2000 J/kg. While low-level shear will be weak, robust speed shear from 700 mb on up will foster an elongated mid/upper-level hodograph favorable for mid-level rotation and an eventual eastward-progressing MCS with potential for a brief bow. Initial large hail transitioning to predominant severe wind gusts should be the main threats before activity weakens in western MN. ...Eastern WY and NE Panhandle... Residual low-level moisture (corridor of upper 50s surface dew points) within a weak upslope regime north of the trailing composite outflow/cold front over northeast CO will support a conditional supercell environment favorable for large hail. However, storm coverage appears likely to be rather isolated at peak heating in the wake of the shortwave trough crossing the Dakotas. Greater confidence in storms exists early Friday morning ahead of the next upstream shortwave impulse. ...Eastern OH and PA vicinity... A low-amplitude upper trough from eastern Lake Superior to western OH will gradually move east with an attendant weak surface cyclone drifting across northern OH. Relatively cool temperatures aloft atop a plume of mid to upper 60s surface dew points should result in MLCAPE reaching 1500-2000 J/kg during the next few hours. Though low-level flow/shear will be weak, there will be sufficient deep-layer vertical shear for multiple mid-level rotating updrafts as scattered storms develop from the Upper OH Valley/Lower Great Lakes regions across the lee of the Appalachians. Convection should remain predominantly discrete, yielding a risk for both severe hail and damaging winds, with these threats waning after dusk. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Aug 15 2019 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER CENTRAL AND EASTERN KS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE NORTHERN/CENTRAL GREAT PLAINS AND THE NORTHERN MID-ATLANTIC STATES INTO PA... ...SUMMARY... Severe thunderstorms are most likely to be centered on eastern Kansas during the late afternoon and evening. Severe hail and wind gusts may be significant with a few tornadoes also possible. ...20Z Update... Overall the forecast remains on track with little change needed. Highest severe thunderstorm coverage is still expected to be across central/eastern KS later this afternoon and evening. Primary change to the outlook is to extend the Slight Risk southeastward across eastern VA and into far northeast NC. Recent trends suggest higher severe coverage across this region. ..Mosier.. 08/15/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Aug 15 2019/ ...Central/eastern KS vicinity... An MCS is ongoing across eastern NE with a trailing composite outflow/cold front extending into far northwest KS. Waning low-level warm advection through the next few hours should inhibit substantial strengthening across the Lower MS Valley. The trailing outflow will be the primary focus for late afternoon to early evening redevelopment. Low-level convergence should support initial storms from north-central into northeast KS. A plume of upper 60s surface dew points at present across central KS will be maintained as richer boundary-layer moisture advects north from OK, beneath the eastern extent of the elevated mixed layer. Ample diabatic heating will yield large buoyancy with MLCAPE likely reaching 2500-3500 J/kg. A veering wind profile with height will support initial supercells, with hodograph enlargement occurring through the evening as a southwesterly low-level jet intensifies. The setup should foster a risk for very large hail and a few tornadoes. However, the overall mode may tend to grow upscale into clusters and an MCS relatively quickly given the strengthening forcing for ascent during the evening. This may result in the predominant threat becoming severe wind gusts (a few of which may be significant) as an MCS develops bowing structures across eastern KS towards western MO/northern OK. Overall severe threat should subside overnight with the most likely MCS track approaching the Ozark Plateau. 12Z non-HRRR HREF members are more consistent with this overall scenario than recent HRRR runs, with the parent RAP maintaining more pronounced MLCIN in much of the warm sector. Nevertheless, an Enhanced Slight Risk appears warranted given the potential for a higher-end intensity/coverage scenario. ...SD vicinity... A low-amplitude shortwave trough and attendant surface boundary will move east across the Dakotas. Ample diabatic heating is underway downstream across central to eastern SD north of the NE MCS. Presence of upper 50s to low 60s boundary-layer dew points will support MLCAPE of at least 1500-2000 J/kg. While low-level shear will be weak, robust speed shear from 700 mb on up will foster an elongated mid/upper-level hodograph favorable for mid-level rotation and an eventual eastward-progressing MCS with potential for a brief bow. Initial large hail transitioning to predominant severe wind gusts should be the main threats before activity weakens in western MN. ...Eastern WY and NE Panhandle... Residual low-level moisture (corridor of upper 50s surface dew points) within a weak upslope regime north of the trailing composite outflow/cold front over northeast CO will support a conditional supercell environment favorable for large hail. However, storm coverage appears likely to be rather isolated at peak heating in the wake of the shortwave trough crossing the Dakotas. Greater confidence in storms exists early Friday morning ahead of the next upstream shortwave impulse. ...Eastern OH and PA vicinity... A low-amplitude upper trough from eastern Lake Superior to western OH will gradually move east with an attendant weak surface cyclone drifting across northern OH. Relatively cool temperatures aloft atop a plume of mid to upper 60s surface dew points should result in MLCAPE reaching 1500-2000 J/kg during the next few hours. Though low-level flow/shear will be weak, there will be sufficient deep-layer vertical shear for multiple mid-level rotating updrafts as scattered storms develop from the Upper OH Valley/Lower Great Lakes regions across the lee of the Appalachians. Convection should remain predominantly discrete, yielding a risk for both severe hail and damaging winds, with these threats waning after dusk. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Aug 15 2019 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER CENTRAL AND EASTERN KS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE NORTHERN/CENTRAL GREAT PLAINS AND THE NORTHERN MID-ATLANTIC STATES INTO PA... ...SUMMARY... Severe thunderstorms are most likely to be centered on eastern Kansas during the late afternoon and evening. Severe hail and wind gusts may be significant with a few tornadoes also possible. ...20Z Update... Overall the forecast remains on track with little change needed. Highest severe thunderstorm coverage is still expected to be across central/eastern KS later this afternoon and evening. Primary change to the outlook is to extend the Slight Risk southeastward across eastern VA and into far northeast NC. Recent trends suggest higher severe coverage across this region. ..Mosier.. 08/15/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Aug 15 2019/ ...Central/eastern KS vicinity... An MCS is ongoing across eastern NE with a trailing composite outflow/cold front extending into far northwest KS. Waning low-level warm advection through the next few hours should inhibit substantial strengthening across the Lower MS Valley. The trailing outflow will be the primary focus for late afternoon to early evening redevelopment. Low-level convergence should support initial storms from north-central into northeast KS. A plume of upper 60s surface dew points at present across central KS will be maintained as richer boundary-layer moisture advects north from OK, beneath the eastern extent of the elevated mixed layer. Ample diabatic heating will yield large buoyancy with MLCAPE likely reaching 2500-3500 J/kg. A veering wind profile with height will support initial supercells, with hodograph enlargement occurring through the evening as a southwesterly low-level jet intensifies. The setup should foster a risk for very large hail and a few tornadoes. However, the overall mode may tend to grow upscale into clusters and an MCS relatively quickly given the strengthening forcing for ascent during the evening. This may result in the predominant threat becoming severe wind gusts (a few of which may be significant) as an MCS develops bowing structures across eastern KS towards western MO/northern OK. Overall severe threat should subside overnight with the most likely MCS track approaching the Ozark Plateau. 12Z non-HRRR HREF members are more consistent with this overall scenario than recent HRRR runs, with the parent RAP maintaining more pronounced MLCIN in much of the warm sector. Nevertheless, an Enhanced Slight Risk appears warranted given the potential for a higher-end intensity/coverage scenario. ...SD vicinity... A low-amplitude shortwave trough and attendant surface boundary will move east across the Dakotas. Ample diabatic heating is underway downstream across central to eastern SD north of the NE MCS. Presence of upper 50s to low 60s boundary-layer dew points will support MLCAPE of at least 1500-2000 J/kg. While low-level shear will be weak, robust speed shear from 700 mb on up will foster an elongated mid/upper-level hodograph favorable for mid-level rotation and an eventual eastward-progressing MCS with potential for a brief bow. Initial large hail transitioning to predominant severe wind gusts should be the main threats before activity weakens in western MN. ...Eastern WY and NE Panhandle... Residual low-level moisture (corridor of upper 50s surface dew points) within a weak upslope regime north of the trailing composite outflow/cold front over northeast CO will support a conditional supercell environment favorable for large hail. However, storm coverage appears likely to be rather isolated at peak heating in the wake of the shortwave trough crossing the Dakotas. Greater confidence in storms exists early Friday morning ahead of the next upstream shortwave impulse. ...Eastern OH and PA vicinity... A low-amplitude upper trough from eastern Lake Superior to western OH will gradually move east with an attendant weak surface cyclone drifting across northern OH. Relatively cool temperatures aloft atop a plume of mid to upper 60s surface dew points should result in MLCAPE reaching 1500-2000 J/kg during the next few hours. Though low-level flow/shear will be weak, there will be sufficient deep-layer vertical shear for multiple mid-level rotating updrafts as scattered storms develop from the Upper OH Valley/Lower Great Lakes regions across the lee of the Appalachians. Convection should remain predominantly discrete, yielding a risk for both severe hail and damaging winds, with these threats waning after dusk. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Aug 15 2019 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER CENTRAL AND EASTERN KS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE NORTHERN/CENTRAL GREAT PLAINS AND THE NORTHERN MID-ATLANTIC STATES INTO PA... ...SUMMARY... Severe thunderstorms are most likely to be centered on eastern Kansas during the late afternoon and evening. Severe hail and wind gusts may be significant with a few tornadoes also possible. ...20Z Update... Overall the forecast remains on track with little change needed. Highest severe thunderstorm coverage is still expected to be across central/eastern KS later this afternoon and evening. Primary change to the outlook is to extend the Slight Risk southeastward across eastern VA and into far northeast NC. Recent trends suggest higher severe coverage across this region. ..Mosier.. 08/15/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Aug 15 2019/ ...Central/eastern KS vicinity... An MCS is ongoing across eastern NE with a trailing composite outflow/cold front extending into far northwest KS. Waning low-level warm advection through the next few hours should inhibit substantial strengthening across the Lower MS Valley. The trailing outflow will be the primary focus for late afternoon to early evening redevelopment. Low-level convergence should support initial storms from north-central into northeast KS. A plume of upper 60s surface dew points at present across central KS will be maintained as richer boundary-layer moisture advects north from OK, beneath the eastern extent of the elevated mixed layer. Ample diabatic heating will yield large buoyancy with MLCAPE likely reaching 2500-3500 J/kg. A veering wind profile with height will support initial supercells, with hodograph enlargement occurring through the evening as a southwesterly low-level jet intensifies. The setup should foster a risk for very large hail and a few tornadoes. However, the overall mode may tend to grow upscale into clusters and an MCS relatively quickly given the strengthening forcing for ascent during the evening. This may result in the predominant threat becoming severe wind gusts (a few of which may be significant) as an MCS develops bowing structures across eastern KS towards western MO/northern OK. Overall severe threat should subside overnight with the most likely MCS track approaching the Ozark Plateau. 12Z non-HRRR HREF members are more consistent with this overall scenario than recent HRRR runs, with the parent RAP maintaining more pronounced MLCIN in much of the warm sector. Nevertheless, an Enhanced Slight Risk appears warranted given the potential for a higher-end intensity/coverage scenario. ...SD vicinity... A low-amplitude shortwave trough and attendant surface boundary will move east across the Dakotas. Ample diabatic heating is underway downstream across central to eastern SD north of the NE MCS. Presence of upper 50s to low 60s boundary-layer dew points will support MLCAPE of at least 1500-2000 J/kg. While low-level shear will be weak, robust speed shear from 700 mb on up will foster an elongated mid/upper-level hodograph favorable for mid-level rotation and an eventual eastward-progressing MCS with potential for a brief bow. Initial large hail transitioning to predominant severe wind gusts should be the main threats before activity weakens in western MN. ...Eastern WY and NE Panhandle... Residual low-level moisture (corridor of upper 50s surface dew points) within a weak upslope regime north of the trailing composite outflow/cold front over northeast CO will support a conditional supercell environment favorable for large hail. However, storm coverage appears likely to be rather isolated at peak heating in the wake of the shortwave trough crossing the Dakotas. Greater confidence in storms exists early Friday morning ahead of the next upstream shortwave impulse. ...Eastern OH and PA vicinity... A low-amplitude upper trough from eastern Lake Superior to western OH will gradually move east with an attendant weak surface cyclone drifting across northern OH. Relatively cool temperatures aloft atop a plume of mid to upper 60s surface dew points should result in MLCAPE reaching 1500-2000 J/kg during the next few hours. Though low-level flow/shear will be weak, there will be sufficient deep-layer vertical shear for multiple mid-level rotating updrafts as scattered storms develop from the Upper OH Valley/Lower Great Lakes regions across the lee of the Appalachians. Convection should remain predominantly discrete, yielding a risk for both severe hail and damaging winds, with these threats waning after dusk. Read more

No watches are valid as of Thu Aug 15 19:57:02 UTC 2019.