Blue Flower

Outlook (Main)

Storm Prediction Center
SPC Forecast Products
  1. No watches are valid as of Mon Oct 25 17:40:02 UTC 2021.
  2. No Mesoscale Discussions are in effect as of Mon Oct 25 17:40:02 UTC 2021.
  3. SPC 1300Z Day 1 Outlook
    Day 1 Outlook Image
    Day 1 Convective Outlook  
    NWS Storm Prediction Center Norman OK
    0749 AM CDT Mon Oct 25 2021
    Valid 251300Z - 261200Z
    Thunderstorms capable of damaging winds and possibly a tornado risk
    are expected from the southern and central Appalachians into the
    Carolinas and Mid-Atlantic region, mainly this afternoon and
    ...Upper Ohio Valley to the Mid-Atlantic States/Carolinas...
    The remnants of last evening's severe storms across the
    Ozarks/Middle Mississippi Valley grew upscale and persist early this
    morning in a diminished intensity from Ohio south-southwestward into
    eastern portions of Kentucky and middle/eastern Tennessee, parallel
    to but ahead of an eastward-moving cold front.
    The parent shortwave trough will continue eastward over the
    Midwest/Ohio Valley toward the central/northern Appalachians through
    tonight, with height falls and the exit region of a strong mid/upper
    jet overspreading the southern Appalachians and Carolinas/Virginia.
    The aforementioned bands of convection and related cloud cover will
    tend to hinder pre-frontal destabilization across the Upper Ohio
    Valley and windward side of the Appalachians, but a few
    strong/severe low-topped storms could occur pending weak but
    sufficient destabilization this afternoon in those areas.
    A more certain/probable severe-weather risk is expected this
    afternoon east of the Appalachians spine, perhaps initially
    near/just east of the Blue Ridge across Virginia and nearby
    Maryland/North Carolina. This is where cloud breaks ahead of the
    upstream cold front and lingering overnight convection should allow
    for modest destabilization, with upwards of 1000 J/kg MLCAPE
    possible from the North Carolina/Virginia Blue Ridge and Piedmont
    vicinities toward the Delmarva by late afternoon. Strong deep-layer
    shear will support some well-organized storms including linear bands
    aside from the possibility of some initial/embedded supercells,
    particularly across the Piedmont of Virginia and northern North
    Although low-level shear will not be overly strong and details of
    convective mode are a bit uncertain, the potential for a tornado or
    two could somewhat increase late this afternoon/early evening. This
    would particularly be across southern Virginia/northern North
    Carolina pending weak lee-side low/trough development and a related
    increase in low-level shear/SRH. Damaging winds will otherwise be
    the most probable hazard across the region this afternoon and
    evening, with a few instances of marginally severe hail also a
    A couple of stronger storms may persist toward and across the
    central/southern Florida Peninsula and Keys vicinity today. However,
    the potential for severe-caliber storms should be limited by
    relatively poor mid-level lapse rates, weak vertical shear, and
    weakening low-level convergence.
    ..Guyer/Kerr.. 10/25/2021
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  4. SPC 1630Z Day 1 Outlook
    Day 1 Outlook Image
    Day 1 Convective Outlook  
    NWS Storm Prediction Center Norman OK
    1127 AM CDT Mon Oct 25 2021
    Valid 251630Z - 261200Z
    Occasional damaging gusts and a tornado or two will be possible this
    afternoon/evening from central North Carolina into Virginia.
    ...Eastern KY/OH to NC/VA this afternoon/evening...
    A midlevel shortwave trough over IN/KY/TN this morning will progress
    eastward to the Appalachians this evening and VA/NC overnight.  An
    associated surface cyclone will move eastward from northeast IN
    across northern OH today while slowly weakening, and a trailing cold
    front will likewise move eastward across TN/KY/WV/OH through this
    evening.  A band of convection will be possible along the cold front
    this afternoon in conjunction with a narrow zone of cloud
    breaks/surface heating and modest low-level moisture (surface
    dewpoints of 56-60 F) across OH/KY.  Buoyancy will remain weak
    (MLCAPE  500 J/kg) and wind profiles will be only modestly
    favorable for organized severe storms (effective bulk shear near 30
    kt) suggest that any severe threat with to storms along the cold
    front should remain marginal.
    Farther east, low-level moisture is increasing from eastern NC into
    VA, on the west side of a separate shortwave trough ejecting
    northeastward near the southeast Atlantic coast.  The moisture
    should be able to spread far enough west and north to support
    thunderstorm development later this afternoon near the Blue Ridge,
    as the primary cloud/ascent band (now across eastern KY into WV)
    reaches the west edge of the richer low-level moisture.  Wind
    profiles will be sufficient for supercells with effective bulk shear
    of 40-50 kt, given MLCAPE up to 1000 J/kg.  Occasional damaging
    gusts will be the main concern, though a tornado or two may also
    occur near the NC/VA border where effective SRH of 100-150 m2/s2 is
    expected by late afternoon.  Otherwise, convection is expected to
    grow upscale into clusters/line segments, with an attendant threat
    for damaging winds through late evening.
    ..Thompson/Wendt.. 10/25/2021
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  5. SPC 1730Z Day 2 Outlook
    Day 2 Outlook Image
    Day 2 Convective Outlook  
    NWS Storm Prediction Center Norman OK
    1234 PM CDT Mon Oct 25 2021
    Valid 261200Z - 271200Z
    Scattered severe thunderstorms associated with large hail, wind
    damage and isolated tornadoes are expected across parts of the
    southern and central Plains from late Tuesday afternoon through the
    evening into the overnight.
    ...Central through southern Plains...
    Upper trough currently moving into the western U.S. will amplify as
    it continues east into the central and southern Plains Tuesday. A
    lee cyclone will develop in association with this feature with the
    strengthening southerly low-level jet drawing partially modified
    Gulf air northward beneath steepening mid-level lapse rates
    resulting in a corridor of moderate instability with up to 1500 J/kg
    MLCAPE. Some low clouds may accompany the moisture return, the
    extent of which remains somewhat uncertain. Storms will likely
    develop by late afternoon as the cold front advances east and merges
    with the dryline. A few discrete storms might initiate along the
    dryline prior to the frontal merger, but extent of this development
    is dependent on the degree of boundary layer heating. More numerous
    storms are expected toward evening as the front begins to merge with
    the dryline from western KS southward into eastern parts of western
    TX. Wind profiles with 40-50 kt effective bulk shear will support
    some supercells with all hazards possible. Storms will eventually
    evolve into an MCS with damaging wind becoming the main threat as
    activity continues east overnight. Some potential exists for a
    greater tornado threat than what is currently indicated, but
    uncertainty regarding extent of boundary layer destabilization and
    mode evolution lowers confidence in increasing probabilities for
    this update.
    ..Dial.. 10/25/2021
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