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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Aug 07 2019 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT ACROSS PARTS OF THE MID ATLANTIC COAST STATES INTO WESTERN NEW ENGLAND...ACROSS PARTS OF THE UPPER MIDWEST...AND ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms are possible today into tonight across parts of the Mid Atlantic Coast states into portions of western New England, across parts of the Upper Midwest, and across parts of the central Plains. These will pose are risk for large hail and potentially damaging wind gusts. ...Synopsis... Blocking appears likely to remain prominent across the mid-latitude eastern Pacific through this period, with a long fetch of northwesterly mid/upper flow downstream, across Alaska and the Yukon Territory through the central Canadian/U.S. border vicinity. On the leading edge of this regime, a large short wave trough and embedded mid-level closed low are forecast to continue digging southeastward, across northern Ontario and the upper Great Lakes region. Models indicate that this will be accompanied by another notable cold front, which is forecast to advance southeastward across much of the northern Plains, Upper Midwest and Great Lakes region by daybreak Thursday. This will be preceded by another cold front, associated with large-scale troughing within a weaker branch of westerlies at lower latitudes, which is expected to continue gradually shifting east of the Mississippi Valley through the Atlantic Seaboard. The lead front may progress southeastward into the Mid Atlantic coast, and more slowly southward through the Tennessee Valley/Ozark Plateau region. It may be reinforced by convective outflow, before stalling across eastern portions of the central Plains. A mid/upper subtropical high, centered over the Four Corners states, may begin to weaken, but large-scale ridging is expected to remain a prominent influence across much of the Intermountain West/Rockies and southern Plains. Subtle short wave perturbations progressing around the periphery of the ridging, into the southern periphery of the broad troughing over the Tennessee Valley/eastern Gulf states, may provide the support and focus for organizing clusters of thunderstorms today through tonight, in the presence of moderate to strong instability. However, the predictability of these features remains relatively low, resulting in only marginal severe probabilities, except across eastern portions of the central Plains. Otherwise, forcing for ascent associated with the more prominent short waves, and destabilization ahead of their associated cold fronts, appear to provide more certain support for severe thunderstorm development. ...Mid Atlantic Coast states into western New England... Although the plume of tropical moisture has advected ahead an initial short wave trough, well east of the Atlantic Seaboard (aside from the southern Florida Peninsula), low-level moisture appears to remain sufficient to support moderate CAPE along pre-frontal surface troughing near/east of the Appalachians. As destabilization commences with daytime heating, 20-40 kt south/southwesterly flow in the 850-500 mb layer is expected to overspread the region and contribute to at least marginally sufficient shear to organize convection and support a risk for potentially damaging wind gusts and some hail. This will be aided by forcing for ascent associated with several smaller-scale perturbations. This may include one mid-level cyclonic vorticity maximum and associated developing area of low pressure, that could contribute to at least low probabilities for a tornado or two across parts of Upstate New York into the Hudson/Champlain Valleys. ...Upper Midwest... Mid-level cooling and forcing for ascent in the exit region of a 50+ kt mid-level jet propagating around the southern periphery of the vigorous digging upper trough will provide support for thunderstorm development late this afternoon or evening. With models generally suggest CAPE at least on the order of 1000-2000 J/kg across parts of eastern Minnesota into Wisconsin and portions of upper Michigan, the environment is expected to become conducive to isolated supercells and small organizing storm clusters posing a risk for severe hail and locally strong surface gusts. ...Eastern portions of the central Plains... Uncertainty exists concerning the extent and intensity of a possible early period cluster of storms now developing across parts of central/eastern Nebraska. However, models generally indicate that an associated outflow boundary/zone of stronger differential surface heating will provide a potential focus for organized severe thunderstorm development late this afternoon into tonight. Large CAPE along and south of the boundary, coupled with favorable shear beneath at least moderate northwest mid-level flow, may become supportive of isolated supercells by early this evening. The nose of a strengthening southerly low-level jet (including 30-40+ kt at 850 mb) may provide the focus for an upscale growing and organizing convective system across northeastern Kansas late this evening into the overnight hours, which could pose a risk for strong surface gusts. ..Kerr/Dean.. 08/07/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Aug 07 2019 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT ACROSS PARTS OF THE MID ATLANTIC COAST STATES INTO WESTERN NEW ENGLAND...ACROSS PARTS OF THE UPPER MIDWEST...AND ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms are possible today into tonight across parts of the Mid Atlantic Coast states into portions of western New England, across parts of the Upper Midwest, and across parts of the central Plains. These will pose are risk for large hail and potentially damaging wind gusts. ...Synopsis... Blocking appears likely to remain prominent across the mid-latitude eastern Pacific through this period, with a long fetch of northwesterly mid/upper flow downstream, across Alaska and the Yukon Territory through the central Canadian/U.S. border vicinity. On the leading edge of this regime, a large short wave trough and embedded mid-level closed low are forecast to continue digging southeastward, across northern Ontario and the upper Great Lakes region. Models indicate that this will be accompanied by another notable cold front, which is forecast to advance southeastward across much of the northern Plains, Upper Midwest and Great Lakes region by daybreak Thursday. This will be preceded by another cold front, associated with large-scale troughing within a weaker branch of westerlies at lower latitudes, which is expected to continue gradually shifting east of the Mississippi Valley through the Atlantic Seaboard. The lead front may progress southeastward into the Mid Atlantic coast, and more slowly southward through the Tennessee Valley/Ozark Plateau region. It may be reinforced by convective outflow, before stalling across eastern portions of the central Plains. A mid/upper subtropical high, centered over the Four Corners states, may begin to weaken, but large-scale ridging is expected to remain a prominent influence across much of the Intermountain West/Rockies and southern Plains. Subtle short wave perturbations progressing around the periphery of the ridging, into the southern periphery of the broad troughing over the Tennessee Valley/eastern Gulf states, may provide the support and focus for organizing clusters of thunderstorms today through tonight, in the presence of moderate to strong instability. However, the predictability of these features remains relatively low, resulting in only marginal severe probabilities, except across eastern portions of the central Plains. Otherwise, forcing for ascent associated with the more prominent short waves, and destabilization ahead of their associated cold fronts, appear to provide more certain support for severe thunderstorm development. ...Mid Atlantic Coast states into western New England... Although the plume of tropical moisture has advected ahead an initial short wave trough, well east of the Atlantic Seaboard (aside from the southern Florida Peninsula), low-level moisture appears to remain sufficient to support moderate CAPE along pre-frontal surface troughing near/east of the Appalachians. As destabilization commences with daytime heating, 20-40 kt south/southwesterly flow in the 850-500 mb layer is expected to overspread the region and contribute to at least marginally sufficient shear to organize convection and support a risk for potentially damaging wind gusts and some hail. This will be aided by forcing for ascent associated with several smaller-scale perturbations. This may include one mid-level cyclonic vorticity maximum and associated developing area of low pressure, that could contribute to at least low probabilities for a tornado or two across parts of Upstate New York into the Hudson/Champlain Valleys. ...Upper Midwest... Mid-level cooling and forcing for ascent in the exit region of a 50+ kt mid-level jet propagating around the southern periphery of the vigorous digging upper trough will provide support for thunderstorm development late this afternoon or evening. With models generally suggest CAPE at least on the order of 1000-2000 J/kg across parts of eastern Minnesota into Wisconsin and portions of upper Michigan, the environment is expected to become conducive to isolated supercells and small organizing storm clusters posing a risk for severe hail and locally strong surface gusts. ...Eastern portions of the central Plains... Uncertainty exists concerning the extent and intensity of a possible early period cluster of storms now developing across parts of central/eastern Nebraska. However, models generally indicate that an associated outflow boundary/zone of stronger differential surface heating will provide a potential focus for organized severe thunderstorm development late this afternoon into tonight. Large CAPE along and south of the boundary, coupled with favorable shear beneath at least moderate northwest mid-level flow, may become supportive of isolated supercells by early this evening. The nose of a strengthening southerly low-level jet (including 30-40+ kt at 850 mb) may provide the focus for an upscale growing and organizing convective system across northeastern Kansas late this evening into the overnight hours, which could pose a risk for strong surface gusts. ..Kerr/Dean.. 08/07/2019 Read more

WW 0557 Status Updates
STATUS REPORT ON WW 557 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 E VTN TO 35 NNW ONL TO 30 NE ONL TO 20 E ONL TO 20 NW OFK. FOR ADDITIONAL INFORMATION SEE SPC MESOSCALE DISCUSSION 1657. ..EDWARDS..08/07/19 ATTN...WFO...OAX...LBF...GID...FSD...UNR... STATUS REPORT FOR WS 557 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC003-009-011-015-017-041-071-077-089-093-103-115-125-149-163- 175-183-070640- NE . NEBRASKA COUNTIES INCLUDED ARE ANTELOPE BLAINE BOONE BOYD BROWN CUSTER GARFIELD GREELEY HOLT HOWARD KEYA PAHA LOUP NANCE ROCK SHERMAN VALLEY WHEELER 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

000
ABPZ20 KNHC 070501
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Tue Aug 6 2019

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

A low pressure area is forecast to form a few hundred miles south
of the southwestern coast of Mexico by the end of the week.
Environmental conditions are expected to be somewhat conducive for
the development of this system over the weekend while it moves
west-northwestward at 10 to 15 mph and offshore of the coast of
Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Pasch

000
ABNT20 KNHC 070500
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Wed Aug 7 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

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

$$
Forecaster Pasch

MD 1657 CONCERNING SEVERE THUNDERSTORM WATCH 557... FOR SOUTH-CENTRAL SOUTH DAKOTA INTO CENTRAL NEBRASKA
Mesoscale Discussion 1657 NWS Storm Prediction Center Norman OK 1024 PM CDT Tue Aug 06 2019 Areas affected...south-central South Dakota into central Nebraska Concerning...Severe Thunderstorm Watch 557... Valid 070324Z - 070530Z The severe weather threat for Severe Thunderstorm Watch 557 continues. SUMMARY...A corridor of very large hail and damaging wind potential stretches from south-central South Dakota into central Nebraska. DISCUSSION...A cluster of supercells continues to travel south-southeastward along the MO River in southern SD, within a weak surface trough and along an instability gradient where modest warm advection exists at 850 mb. West of the primary cluster, several smaller cells were affecting far northern NE, with indications of marginally severe hail. The 00Z LBF sounding shows strong instability along with a long, straight hodograph and minimal capping potential given mid to upper 60s F dewpoints. As 850 mb winds remain out of the southwest, the cluster of supercells is likely to persist for several hours, with damaging hail and wind possible into central NE. ..Jewell.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...OAX...GID...LBF...UNR... LAT...LON 43269970 43459943 43519904 43179879 42699852 42029823 41349801 41019816 40899860 40909932 41239963 41939963 42639965 43269970 Read more

WW 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY 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 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY 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 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY 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 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY 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 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NW PIR TO 45 SSW ABR TO 35 W BKX. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC031-103-070340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE FOSTER WELLS SDC017-059-065-069-075-085-115-117-119-070340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUFFALO HAND HUGHES HYDE JONES LYMAN SPINK STANLEY SULLY 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 556 SEVERE TSTM ND SD 061950Z - 070400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 556 NWS Storm Prediction Center Norman OK 250 PM CDT Tue Aug 6 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of central and southern North Dakota northern South Dakota * Effective this Tuesday afternoon and evening from 250 PM until 1100 PM CDT. * Primary threats include... Scattered large hail likely with isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Severe storms are expected to increase in coverage this afternoon and continue into the evening. Initial primary threat will be supercells with large to very large hail and downburst winds, though a brief tornado cannot be ruled out. Threat will transition to damaging wind as storms develop southeast into South Dakota this evening. The severe thunderstorm watch area is approximately along and 85 statute miles east and west of a line from 15 miles east northeast of Garrison ND to 75 miles south southwest of Aberdeen SD. 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. && OTHER WATCH INFORMATION...CONTINUE...WW 555... 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 500. Mean storm motion vector 31035. ...Dial Read more

WW 0557 Status Updates
STATUS FOR WATCH 0557 HAS NOT BEEN ISSUED YET Read more

WW 0557 Status Updates
STATUS FOR WATCH 0557 HAS NOT BEEN ISSUED YET Read more

WW 0557 Status Updates
STATUS FOR WATCH 0557 HAS NOT BEEN ISSUED YET Read more

MD 1656 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR MIDDLE TN...SOUTH-CENTRAL KY
Mesoscale Discussion 1656 NWS Storm Prediction Center Norman OK 0819 PM CDT Tue Aug 06 2019 Areas affected...Middle TN...South-central KY Concerning...Severe potential...Watch unlikely Valid 070119Z - 070245Z Probability of Watch Issuance...20 percent SUMMARY...Isolated damaging winds are possible until around 02-03Z with ongoing thunderstorm complex, but a gradual weakening trend is expected with time. Watch issuance is not anticipated. DISCUSSION...Consolidation of earlier thunderstorms across KY has resulted in a forward-propagating cluster moving into middle TN. KOHX radar depicts surging outflow approaching the Nashville metro area, which will result in a short-term damaging wind risk between now and at least 02Z. The 00Z BNA sounding was moderately unstable (MLCAPE ~1500 J/kg), though low-level flow was weak and deep-layer shear only marginally favorable for organized convection. With these factors in mind, a gradual weakening trend is expected with time as the boundary layer stabilizes this evening. However, some threat for damaging wind will likely continue until around the 02-03Z timeframe as the complex and associated cold pool continue southeastward across middle TN. Due to the relatively limited duration of the anticipated threat, watch issuance is not expected. ..Dean/Thompson.. 08/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LMK...OHX...MEG... LAT...LON 36408833 36528699 36878632 37148594 37338582 37288527 36548507 36098532 35578589 35348677 35358746 35398785 35558828 36088851 36408833 Read more

WW 0556 Status Updates
STATUS REPORT ON WW 556 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NNE PHP TO 40 SSW MBG TO 15 SSE MBG TO 45 NNE MBG TO 45 NE BIS TO 50 W DVL. ..JEWELL..08/07/19 ATTN...WFO...BIS...ABR... STATUS REPORT FOR WS 556 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC021-031-043-045-047-051-093-103-070240- ND . NORTH DAKOTA COUNTIES INCLUDED ARE DICKEY FOSTER KIDDER LAMOURE LOGAN MCINTOSH STUTSMAN WELLS SDC013-017-021-045-049-059-065-069-075-085-089-107-115-117-119- 129-070240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CAMPBELL EDMUNDS FAULK HAND HUGHES HYDE JONES LYMAN MCPHERSON POTTER SPINK STANLEY SULLY WALWORTH Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Tue Aug 06 2019 Valid 070100Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... A few severe thunderstorms remain possible this evening into the overnight hours across parts of the northern Plains, mainly across parts of the central and eastern Dakotas into northern Nebraska. ...01Z Outlook Update... ...Dakotas/Nebraska... Latest observational data and model output indicate that low-level ridging remains a fairly prominent feature, centered across the mid Missouri Valley, roughly between Pierre SD and Omaha NE. Some erosion/weakening appears possible later this evening into the overnight hours, as lower/mid tropospheric warm advection strengthens across parts of south central South Dakota into northern Nebraska, well ahead of a vigorous short wave trough and deepening embedded mid-level low digging across Manitoba and northern Ontario. Scattered thunderstorm development which initiated across southwestern and central North Dakota, in response to a subtle preceding perturbation migrating around the periphery of the western U.S. mid/upper ridging, has shown recent signs of diminishing. However, the environment across western and central Nebraska into south central South Dakota, on the western periphery of the low-level ridging into weak surface troughing, remains characterized by moderate to strong potential instability (CAPE of 1500-3000 J/kg). The latest Rapid Refresh continues to suggest that new vigorous thunderstorm development is possible during the 03-06Z time frame in response to forcing for ascent with the warm advection, perhaps aided by a modest southwesterly low-level jet across the Nebraska panhandle into the central South Dakota/Nebraska border area. In the presence of strong shear beneath 30-40 kt northwesterly 500 mb flow, some of this activity may become capable of producing severe hail and strong wind gusts, with the evolution of an upscale growing and organizing cluster of thunderstorms possible overnight. ...Parts of Tennessee Valley... Instability ahead a conglomerate southward advancing, convectively generated surface cold pool, modest deep-layer shear, and perhaps forcing for ascent associated with a subtle perturbation within broadly cyclonic mid-level flow, may maintain vigorous thunderstorm activity south of the Kentucky/Tennessee border. This may be accompanied by at least some continuing risk for wind gusts approaching severe limits, across much of western and middle Tennessee through 03-05Z, before activity begins to diminish in weaker/waning instability. ..Kerr.. 08/07/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Tue Aug 06 2019 Valid 070100Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... A few severe thunderstorms remain possible this evening into the overnight hours across parts of the northern Plains, mainly across parts of the central and eastern Dakotas into northern Nebraska. ...01Z Outlook Update... ...Dakotas/Nebraska... Latest observational data and model output indicate that low-level ridging remains a fairly prominent feature, centered across the mid Missouri Valley, roughly between Pierre SD and Omaha NE. Some erosion/weakening appears possible later this evening into the overnight hours, as lower/mid tropospheric warm advection strengthens across parts of south central South Dakota into northern Nebraska, well ahead of a vigorous short wave trough and deepening embedded mid-level low digging across Manitoba and northern Ontario. Scattered thunderstorm development which initiated across southwestern and central North Dakota, in response to a subtle preceding perturbation migrating around the periphery of the western U.S. mid/upper ridging, has shown recent signs of diminishing. However, the environment across western and central Nebraska into south central South Dakota, on the western periphery of the low-level ridging into weak surface troughing, remains characterized by moderate to strong potential instability (CAPE of 1500-3000 J/kg). The latest Rapid Refresh continues to suggest that new vigorous thunderstorm development is possible during the 03-06Z time frame in response to forcing for ascent with the warm advection, perhaps aided by a modest southwesterly low-level jet across the Nebraska panhandle into the central South Dakota/Nebraska border area. In the presence of strong shear beneath 30-40 kt northwesterly 500 mb flow, some of this activity may become capable of producing severe hail and strong wind gusts, with the evolution of an upscale growing and organizing cluster of thunderstorms possible overnight. ...Parts of Tennessee Valley... Instability ahead a conglomerate southward advancing, convectively generated surface cold pool, modest deep-layer shear, and perhaps forcing for ascent associated with a subtle perturbation within broadly cyclonic mid-level flow, may maintain vigorous thunderstorm activity south of the Kentucky/Tennessee border. This may be accompanied by at least some continuing risk for wind gusts approaching severe limits, across much of western and middle Tennessee through 03-05Z, before activity begins to diminish in weaker/waning instability. ..Kerr.. 08/07/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0757 PM CDT Tue Aug 06 2019 Valid 070100Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... A few severe thunderstorms remain possible this evening into the overnight hours across parts of the northern Plains, mainly across parts of the central and eastern Dakotas into northern Nebraska. ...01Z Outlook Update... ...Dakotas/Nebraska... Latest observational data and model output indicate that low-level ridging remains a fairly prominent feature, centered across the mid Missouri Valley, roughly between Pierre SD and Omaha NE. Some erosion/weakening appears possible later this evening into the overnight hours, as lower/mid tropospheric warm advection strengthens across parts of south central South Dakota into northern Nebraska, well ahead of a vigorous short wave trough and deepening embedded mid-level low digging across Manitoba and northern Ontario. Scattered thunderstorm development which initiated across southwestern and central North Dakota, in response to a subtle preceding perturbation migrating around the periphery of the western U.S. mid/upper ridging, has shown recent signs of diminishing. However, the environment across western and central Nebraska into south central South Dakota, on the western periphery of the low-level ridging into weak surface troughing, remains characterized by moderate to strong potential instability (CAPE of 1500-3000 J/kg). The latest Rapid Refresh continues to suggest that new vigorous thunderstorm development is possible during the 03-06Z time frame in response to forcing for ascent with the warm advection, perhaps aided by a modest southwesterly low-level jet across the Nebraska panhandle into the central South Dakota/Nebraska border area. In the presence of strong shear beneath 30-40 kt northwesterly 500 mb flow, some of this activity may become capable of producing severe hail and strong wind gusts, with the evolution of an upscale growing and organizing cluster of thunderstorms possible overnight. ...Parts of Tennessee Valley... Instability ahead a conglomerate southward advancing, convectively generated surface cold pool, modest deep-layer shear, and perhaps forcing for ascent associated with a subtle perturbation within broadly cyclonic mid-level flow, may maintain vigorous thunderstorm activity south of the Kentucky/Tennessee border. This may be accompanied by at least some continuing risk for wind gusts approaching severe limits, across much of western and middle Tennessee through 03-05Z, before activity begins to diminish in weaker/waning instability. ..Kerr.. 08/07/2019 Read more