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  • DAY48SVR: Nws Storm Prediction Center Norman Ok

    From COD Weather Processor @1:2320/107 to All on Tue Aug 4 09:02:16 2026
    ACUS48 KWNS 040902
    SWOD48
    SPC AC 040900

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0400 AM CDT Tue Aug 04 2026

    Valid 071200Z - 121200Z

    ...DISCUSSION...
    An upper high will remain over the southwestern states through much
    of the period, with a deep upper low gradually shifting eastward
    across Ontario Canada. In between, a zone of moderate northwest flow
    aloft will exist from the northern Plains/Upper MS Valley across the
    Great Lakes. At the surface, low pressure will exist over the
    central High Plains, with an east-west boundary roughly along I-80
    from Nebraska eastward.

    Stronger cyclonic flow aloft will move out of the northern Plains on
    Fri/D4 and increase across the Great Lakes and into the Northeast
    from Sat/D5 through the end of the period, with midlevel winds
    around 30-40 kt possibly overspreading the surface front. A large
    area of upper 60s to lower 70s F dewpoints will remain along and
    south of the boundary, which may shift north/south as disturbances
    rotate around the Canadian upper low. Predictability remains low for
    denoting precise MCS corridors, but timing of the upper wave
    amplifications will be monitored in subsequent forecast cycles, with
    possible risk areas mainly for damaging wind potential.

    ..Jewell.. 08/04/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 09:02:48 2026
    ACUS48 KWNS 050902
    SWOD48
    SPC AC 050900

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0400 AM CDT Wed Aug 05 2026

    Valid 081200Z - 131200Z

    ...DISCUSSION...
    ...Saturday/D4...
    Southwest midlevel winds of only 25 kt will exist across the
    Northeast, while low-level moisture remains in place supporting up
    to 2000 J/kg MUCAPE with poor lapse rates aloft. This will support
    daytime thunderstorms over a large area from the Appalachians into
    the Northeast, and a few severe gusts cannot be ruled out.
    Otherwise, normal gusty outflow winds are to be expected.

    To the west, an area of stronger instability is forecast across the
    Mid MO Valley, where northwesterly midlevel winds of 35 kt will
    exist along the southern periphery of a trough sweeping across the
    Upper Great Lakes. Evening/overnight storms may occur across parts
    of eastern NE, IA, and MO, and instability may be large enough to
    warrant at least low severe probabilities as the event nears in
    time.

    ...Sunday/D5...
    Drying will occur aloft over parts of the Northeast as a wave moves
    into Quebec, but substantial low-level moisture will still support
    scattered thunderstorms ahead of a cold front across the Mid
    Atlantic. Shear will again be weak, but perhaps enough mean wind
    speeds will exist for storms to be mobile/produce areas of strong
    gusts.

    To the west, low-level moisture is forecast to shift a bit farther
    north into the Dakotas, and this will occur beneath stronger
    northwest flow aloft. This area bears watching in later outlooks, as
    wind profiles may somewhat favor supercells. Predictability is
    currently low.

    ...Mon/D6 to Wed/D8...
    While predictability decreases further during this time frame,
    moderate west to northwest flow aloft will remain from the upper MS
    Valley across the Great Lakes, which will spread into the Northeast
    D7/D8. If a wave does amplify within this flow regime, a corridor of
    damaging winds could develop given upper 60s to low 70s F dewpoints
    along/south of the mean frontal zone (roughly IA to NY/PA by end of
    the period). Model variation is currently too great to depict an
    precise corridor.

    ..Jewell.. 08/05/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Aug 6 08:02:02 2026
    ACUS48 KWNS 060801
    SWOD48
    SPC AC 060800

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0300 AM CDT Thu Aug 06 2026

    Valid 091200Z - 141200Z

    ...DISCUSSION...
    For the Sunday/D4 through Thursday/D8 period, an elongated zone of thunderstorm/wind potential will exist from the northern Plains
    across parts of the Midwest/Great Lakes, and possibly extending into
    parts of the Northeast. Predictability is low for this pattern given
    the likelihood of ongoing corridors of storms early each day, and
    variability with the position of the elongated west to east front.
    However, the presence of a very moist air mass, with possibly strong instability to the south, combined with possible waves rotating
    around the large-scale upper trough over Canada, may yield storm
    corridors with damaging wind potential. One or more areas may be
    denoted in later outlooks as the events near in time.

    At this time, rough areas of interest include the northern Plains to
    Upper Midwest on Sunday/D4, and portions of the Great Lakes/Midwest
    on Monday/D5.

    ..Jewell.. 08/06/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Aug 7 09:01:46 2026
    ACUS48 KWNS 070901
    SWOD48
    SPC AC 070859

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0359 AM CDT Fri Aug 07 2026

    Valid 101200Z - 151200Z

    ...DISCUSSION...
    ...Monday/Day 4 to Wednesday/Day 6...
    A broad cyclonic flow pattern is forecast to remain in place from
    the north-central U.S. to the Northeast during the early to
    mid-week. On the southern edge of the stronger flow, it appears that
    an east-to-west corridor of moisture and instability will remain in
    place from the central Plains eastward into the Midwest. On Monday,
    isolated to scattered thunderstorm development will be possible
    during the afternoon and evening along and near the northern edge of
    the stronger instability, from eastern Nebraska eastward into the
    southern Great Lakes. The greatest convective coverage is expected
    to be from northern Illinois eastward into western Pennsylvania,
    where low-level flow is forecast to be maximized. Moderate
    deep-layer shear along this zone is forecast to be favorable for a
    severe threat Monday afternoon and evening. Supercells and multicell
    line segments will have potential to produce severe wind gusts.

    On Tuesday and Wednesday, model forecasts suggest that a front will
    move southward into northern sections of the Ohio Valley, while the
    instability axis remains in a similar position further west near the
    Omaha area. Isolated to scattered thunderstorms will again be
    possible in the afternoon and evening, near and to the north of the
    instability axis. An isolated severe threat could develop with
    storms that form within or near the strongest instability. However, predictability is low concerning where the greatest potential for
    severe storms will be.

    ...Thursday/Day 7 and Friday/Day 8...
    On Thursday and Friday, west to northwesterly mid-level flow is
    forecast over much of the eastern half of the nation. A moist and
    unstable airmass should be in place from the central and northern
    Plains southeastward into the Ohio and Tennessee Valleys. Although
    large-scale ascent may be relatively weak over much of this area,
    isolated to scattered thunderstorms will be possible across parts of
    this airmass during the afternoon and evening. Due to the extended
    time range, predictability remains low concerning the finer-scale
    details of any scenario from Thursday into Friday.

    ..Broyles.. 08/07/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 8 08:57:46 2026
    ACUS48 KWNS 080857
    SWOD48
    SPC AC 080855

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0355 AM CDT Sat Aug 08 2026

    Valid 111200Z - 161200Z

    ...DISCUSSION...
    ...Tuesday/Day 4 and Wednesday/Day 5...
    A broad cyclonic mid-level flow pattern is forecast from the upper
    Mississippi Valley into the Northeast on Tuesday and Wednesday. At
    the surface, a moist airmass is forecast to be in place over most of
    the eastern half of the nation with a quasi-stationary front located
    from the northern Plains east-southeastward into the southern Great
    Lakes. To the south of the front, surface dewpoints in the 70s F
    will likely result in the development of moderate to strong
    instability. Isolated to scattered thunderstorms appear likely to
    develop each afternoon in areas where low-level convergence becomes
    maximized. Outflow boundaries will be important in determining where
    the greatest convective coverage ends up being. In addition to the
    instability, moderate deep-layer shear is forecast over much of this
    moist airmass suggesting that an isolated wind-damage threat will be
    possible. However, the lack of any appreciable mid-level shortwave
    trough introduces considerable uncertainty.

    ...Thursday/Day 6 and Saturday/Day 8...
    From Thursday to Saturday, mid-level flow is forecast to become
    westerly over much of the northern U.S, with a front located from
    the central Plains eastward into the southern Great Lakes and Ohio
    Valley. Thunderstorm development will be possible each afternoon and
    evening near this front. Surface dewpoints in the 70s F to the south
    of the front, along with moderate to strong instability will make
    isolated severe thunderstorms possible each afternoon and evening.
    However, spatial uncertainty concerning any potential severe threat
    is considerable at this range.

    ..Broyles.. 08/08/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 9 09:00:48 2026
    ACUS48 KWNS 090900
    SWOD48
    SPC AC 090858

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0358 AM CDT Sun Aug 09 2026

    Valid 121200Z - 171200Z

    ...DISCUSSION...
    ...Wednesday/Day 4 to Friday/Day 6...
    From Wednesday to Friday, a broad mid-level cyclonic flow pattern is
    forecast to remain in place across the Great Lakes and the
    Northeast, as a ridge moves eastward from the northern Rockies into
    the upper Mississippi Valley. At the surface, a cold front is
    forecast to become quasi-stationary from the central and northern
    Plains into the mid Missouri and Ohio Valleys. Low-level convergence
    near this front will be a focus for convective development each day.


    On Wednesday, model forecasts suggest that scattered thunderstorms
    will most likely develop Wednesday afternoon along an axis of
    moderate instability from western Nebraska into southwestern South
    Dakota. The storms will be supported by a mid-level shortwave trough
    moving across the north-central U.S. Moderate deep-layer shear near
    the instability axis should support a severe threat during the
    afternoon and evening. The models also suggest that a convective
    cluster will form within a very moist and unstable airmass in the
    central Appalachians Wednesday afternoon, where a wind-damage threat
    will be possible.

    On Thursday, the most favored corridor for convective development is
    forecast from eastern Nebraska into central Illinois. However, the
    models suggest that scattered convective coverage could be
    concentrated overnight as low-level flow increases across the
    region. A severe threat could develop during the day but would
    remain relatively isolated due to a lack of storm coverage. An
    isolated severe threat could also develop across parts of the
    central and northern High Plains during the afternoon. However,
    storms there will also likely be isolated due to a shortwave ridge
    aloft.

    On Friday, thunderstorm swill also be possible from the central
    Plains eastward into the Ohio Valley during the afternoon and
    evening. However, the most favored locations are likely to be
    determined by outflow boundaries associated with the previous day's
    convection. For this reason, uncertainty is substantial on Friday.

    ...Saturday/Day 7 and Sunday/Day 8...
    Over the weekend, a mid-level shortwave ridge is forecast to move
    across the north-central U.S., as west-northwesterly flow remains in
    the Northeast. An axis of instability is forecast from the central
    Plains into the Ohio Valley, which will be a focus for thunderstorm development. It appears that an isolated severe threat could develop
    along and near the instability axis each afternoon and evening.
    However, uncertainty is considerable concerning the details of any
    potential scenario.

    ..Broyles.. 08/09/2026

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    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 10 08:57:00 2026
    ACUS48 KWNS 100856
    SWOD48
    SPC AC 100854

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0354 AM CDT Mon Aug 10 2026

    Valid 131200Z - 181200Z

    ...DISCUSSION...
    ...Thursday/Day 4 to Saturday/Day 6...
    A mid-level ridge is forecast to move eastward through the
    north-central U.S. on Thursday and into the Great Lakes region on
    Friday. At the surface, a moist axis is forecast to remain in place
    from the central Plains east-southeastward into the lower Ohio
    Valley. Moderate to strong instability along the moist axis will
    make isolated severe thunderstorms possible each afternoon and
    evening. Additionally, a severe threat may develop near mid-level
    shortwave troughs that are forecast to move through the northern
    Plains and Mid-Atlantic on Friday.

    On Saturday, a mid-level shortwave trough is forecast to move
    through the Great Lakes region. Moderate to strong instability may
    be in place over much of Illinois, Indiana and Ohio by afternoon.
    Along the northern edge of the stronger instability, isolated severe thunderstorms will be possible from Lower Michigan eastward into the
    central Appalachians Saturday afternoon. Additional severe storms
    may develop along an axis of moderate instability over parts of the
    central Plains in the afternoon and evening.

    Concerning the severe potential from Thursday to Saturday,
    considerable variance exists among the model solutions concerning
    the position of features, suggesting uncertainty is still too great
    to add a threat area.

    ...Sunday/Day 7 and Monday/Day 8...
    From Sunday into Monday, a broad cyclonic flow pattern is forecast
    to develop over the northeastern U.S. A cold front is forecast to
    move southward across the central and southern Appalachians. This
    boundary would be the primary focus for convective development each
    afternoon and evening. Ahead of the front, surface dewpoints in the
    70s F along with moderate to strong instability would likely support
    an isolated severe threat. However, considerable uncertainty exists
    concerning the timing of the front. For this reason, predictability
    is low at this extended range.

    ..Broyles.. 08/10/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 11 08:15:56 2026
    ACUS48 KWNS 110815
    SWOD48
    SPC AC 110813

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0313 AM CDT Tue Aug 11 2026

    Valid 141200Z - 191200Z

    ...DISCUSSION...
    ...D4/Friday...
    Moderate to strong destabilization will again be possible on Friday,
    near and south of a front extending from the central Plains and
    Midwest into parts of the southern Mid-Atlantic. Considerable
    uncertainty remains regarding the exact frontal position, but strong
    storms will be possible in its vicinity. Most guidance depicts
    rising midlevel heights and modest deep-layer flow/shear in the
    vicinity of the frontal zone, which may tend to keep the severe
    threat isolated. One possible exception will be in the Carolinas and
    southern VA, where the glancing influence of a seasonably deep upper
    trough over the Northeast may result in a somewhat more organized
    severe threat, if sufficient destabilization can occur.

    ...D5/Saturday - D6/Sunday...
    Some dampening of the upper ridge (potentially aided by one or more
    MCVs emerging from the High Plains) may result in severe potential
    emerging this weekend across parts of the Upper Midwest and Great
    Lakes/Ohio Valley. However, details regarding timing of any
    shortwave troughs and position of the primary frontal zone remain
    quite uncertain.

    ...D7/Monday - D8/Tuesday...
    Extended-range guidance generally suggests potential for a
    northwesterly flow regime to develop from the northern Plains into
    parts of the East by early next week. Predictability remains quite
    low regarding the extent to which stronger deep-layer flow impinges
    upon favorable instability, but at least isolated severe potential
    may eventually develop from parts of the north-central CONUS into
    the Mid-Atlantic and Carolinas.

    ..Dean.. 08/11/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 12 08:37:58 2026
    ACUS48 KWNS 120837
    SWOD48
    SPC AC 120835

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0335 AM CDT Wed Aug 12 2026

    Valid 151200Z - 201200Z

    ...DISCUSSION...
    ...D4/Saturday...
    Most guidance depicts one or more midlevel vorticity maxima cresting
    the upper ridge and moving across the Upper Midwest/Great Lakes
    region on Saturday. However, there is considerable spread regarding
    the timing of these features and the northward extent of substantial destabilization. The general pattern suggests some potential for MCS development across parts of the Midwest/Great Lakes region, but
    uncertainty regarding the favored corridor precludes addition of 15% probabilities at this time.

    ...D5/Sunday...
    Extended-range guidance is in general agreement depicting a cold
    front that will move across parts of the Midwest, Great Lakes, Ohio
    Valley, and Northeast on Sunday. This front will impinge upon a
    reservoir of rich moisture and moderate to locally strong buoyancy,
    which could result in a severe-thunderstorm threat along/ahead of
    the front. Substantial timing differences remain regarding the
    front, but severe probabilities may eventually be needed for this
    scenario.

    ...D6/Monday - D7/Tuesday...
    A similar upper-level pattern is expected to persist into early next
    week, with west-northwesterly midlevel flow extending from the
    northern Plains into the Midwest/Great Lakes and
    Northeast/Mid-Atlantic. This pattern will continue to favor at least
    an isolated severe threat, with low-predictability MCS potential.

    ..Dean.. 08/12/2026

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    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Sep 5 07:55:52 2026
    ACUS48 KWNS 050746
    SWOD48
    SPC AC 050744

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0244 AM CDT Sat Sep 05 2026

    Valid 081200Z - 131200Z

    ...DISCUSSION...
    ...Days 4-6/Tue-Thu -- Central Plains to Great Lakes/Ohio Valley and Mid-Atlantic...

    An upper shortwave trough will shift east across the Upper
    Midwest/Great Lakes and northeast through Thursday. An associated
    surface low will mainly remain over Canada, but a trailing cold
    front will sweep across parts of the central Plains and Upper
    Midwest on Tuesday, before continuing south and east into Kansas and
    across the Great Lakes on Wednesday. By Thursday, the boundary is
    expected to continue south and east across the Ohio Valley and
    Mid-Atlantic. Stronger large-scale ascent will likely remain focused
    near and north of the international border. Furthermore, the
    corridor of deeper boundary layer moisture may be somewhat limited,
    especially Tuesday into Wednesday, due to a prior cold frontal
    passage and surface high pressure over the Midwest. Nevertheless,
    enhanced deep-layer flow, and corridors of at least modest
    instability along the cold front could support some severe risk.
    However, confidence in 15 percent or greater coverage is low at this
    time frame.

    ...Days 7-8/Fri-Sat -- Northern/Central Plains to Upper Midwest...

    At the end of the period, another upper shortwave trough may dig
    southeast from the Pacific Northwest and into the Plains. Another,
    perhaps stronger, cold front could sweep across the Plains and the
    Mid/Upper MS Valley. Depending on moisture return in the wake of the
    earlier cold frontal passage, some severe risk could develop during
    the weekend. Furthermore, large spread exists among various guidance
    regarding the evolution of the this upper trough, resulting in
    uncertainty in greater corridors of severe potential.

    ..Leitman.. 09/05/2026

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    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Sep 6 07:51:36 2026
    ACUS48 KWNS 060751
    SWOD48
    SPC AC 060749

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0249 AM CDT Sun Sep 06 2026

    Valid 091200Z - 141200Z

    ...DISCUSSION...
    An upper shortwave trough will move from the Great Lakes and over
    the Northeast through Day 5/Thursday. As this occurs, a cold front
    will develop southeast and east across much of the Midwest and
    Northeast. Some strong to severe thunderstorm potential could
    develop near the front, especially on Wednesday across parts of the
    Midwest. However, deep-layer flow will largely remain parallel to
    the boundary and stronger flow aloft will remain displaced to the
    north of better instability.

    Lower amplitude westerly upper-level flow is expected on Day
    6/Friday before another upper trough digs southeast across the
    western U.S. and emerges into the Plains by Day 8/Sunday. Some
    severe potential could return to the Plains during the weekend as
    low-level moisture returns across the region and lee cyclogenesis
    occurs with the approach of the late-period upper trough. Trends
    will be monitored and probabilities may become necessary across
    parts of the central Plains vicinity if confidence in severe
    potential increase.

    ..Leitman.. 09/06/2026

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    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Sep 7 07:34:00 2026
    ACUS48 KWNS 070733
    SWOD48
    SPC AC 070732

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0232 AM CDT Mon Sep 07 2026

    Valid 101200Z - 151200Z

    ...DISCUSSION...
    An upper shortwave trough will weaken as it spread east across the
    Northeast on Day 4/Thursday. As this occurs, a surface cold front
    will shift east/southeast across the Northeast and the Mid-Atlantic.
    A moist airmass will be in place, but vertical shear will weaken
    through the day and deep-layer flow will remain parallel to the
    surface boundary. Thunderstorms are expected in the vicinity of the
    front, but may tend to be just to the cool side of the boundary.
    Nevertheless, some low-end severe potential could develop from the
    Ohio Valley to the Mid-Atlantic as the front sags southward across
    the region.

    During the weekend into early next week, forecast guidance suggests
    a more progressive upper pattern will emerge across the northern
    tier of the U.S. A series of shortwave upper troughs will move from
    the northern Rockies to the Great Lakes and eventually the Northeast
    during this time. Some severe risk is likely to develop ahead of the
    upper shortwave troughs around the Day 5/Friday to Day 8/Monday time
    period. However, large spread exists in both the timing and
    intensity of these upper trough, resulting in vastly different
    evolution and timing of key surface features (mainly surface low
    position). These differences have large implications for where the
    best corridors of severe potential will ultimately develop, but
    severe probabilities may become necessary in later outlooks for
    portions the northern/central Plains to the Upper Midwest during the
    weekend.

    ..Leitman.. 09/07/2026

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    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Sep 8 07:26:44 2026
    ACUS48 KWNS 080726
    SWOD48
    SPC AC 080724

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0224 AM CDT Tue Sep 08 2026

    Valid 111200Z - 161200Z

    ...DISCUSSION...
    ...Days 4-5/Fri-Sat -- Plains to the Great Lakes vicinity...

    Severe potential could develop across portions of the Plains into
    the Upper Midwest on Day 4/Friday as boundary layer moisture spreads
    northward ahead of a southeastward-advancing cold front. Moderate to
    strong destabilization ahead of the front, and enhanced vertical
    shear courtesy of a modest upper shortwave trough moving across the
    northern Plains/Upper Midwest vicinity, should be sufficient for
    organized convection mainly from Friday evening into early Saturday.

    Some severe potential could persist into Day 5 Saturday as the
    surface front stalls over the central/southern Plains vicinity but
    continues eastward across the upper Great Lakes region. A moist
    boundary layer will be in place, but stronger flow aloft will become
    increasing displaced to the north of stronger instability,
    precluding 15 percent delineation at this time.

    ...Days 6-8/Sun-Tue...

    An upper trough over the northwestern U.S. will develop eastward
    across the Plains and Great Lakes early next week. Another cold
    front will move across the area, and some severe potential could
    again sweep across the Plains to the Upper Midwest/Great Lakes
    vicinity. Medium range forecast guidance generally maintains
    stronger instability offset from enhanced flow aloft, partly due to
    the early cold frontal passage in the Day 4-5/Friday-Saturday time
    frame and strong surface high pressure over the Great Lakes in the
    wake of that frontal passage. Trends will be monitored and
    probabilities could become necessary in later outlooks.

    ..Leitman.. 09/08/2026

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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)