• MESO: Mesoscale Discussion 0422

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Tue Apr 14 18:55:59 2026
    ACUS11 KWNS 141855
    SWOMCD
    SPC MCD 141855=20
    INZ000-ILZ000-142100-

    Mesoscale Discussion 0422
    NWS Storm Prediction Center Norman OK
    0155 PM CDT Tue Apr 14 2026

    Areas affected...Parts of central IL into northern/central IN

    Concerning...Severe potential...Watch possible=20

    Valid 141855Z - 142100Z

    Probability of Watch Issuance...40 percent

    SUMMARY...The area is being monitored for an increasing severe risk.
    While confidence in overall storm development/coverage and evolution
    remains uncertain, a watch issuance is possible this afternoon.

    DISCUSSION...In the vicinity of a remnant/increasingly diffuse
    outflow boundary draped across parts of northern/central IL, weak
    low-level warm advection is promoting gradually deepening cumulus
    and isolated convective initiation in central IL. Based on the
    motion of these echoes and character of the cumulus on day cloud
    phase imagery, this activity may be rooted above the boundary layer. Nevertheless, temperatures climbing into the lower 80s amid
    middle/upper 60s dewpoints will continue to erode inhibition at the
    base of the EML and could eventually support a transition to
    surface-based updrafts. If this were to occur, 2000-3000 J/kg MLCAPE
    and 40-50 kt of effective shear (characterized by a long/mostly
    straight hodograph) would initially favor discrete/semi-discrete
    supercells and clusters -- with a risk of very large hail (some 2+
    inches in diameter) and severe wind gusts. With time, a
    strengthening low-level jet will result in enlarging
    clockwise-curved hodographs (200-300 m2/s2 effective SRH) and an
    increasing supercell-tornado risk.=20

    With all that said, the limited/nebulous synoptic and mesoscale
    ascent casts uncertainty on storm development/coverage and overall
    evolution -- especially given lingering inhibition. Convective and environmental trends are being monitored, and a watch issuance is
    possible this afternoon.

    ..Weinman/Gleason.. 04/14/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9PrbAao0qwMfAEARmV5FF85YCMz4GULMLpNgvw9WhLwMSigL-vILekh1WE4eZuZBwSPA-uc0M= LMCwmJlMtuqpKu3AVg$ for graphic product...

    ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN...

    LAT...LON 39088910 39288995 39649033 40049057 40599064 41049034
    41428980 41578728 41458650 41168587 40298545 39698564
    39418603 39088910=20

    MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH
    MOST PROBABLE PEAK WIND GUST...55-70 MPH
    MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


    =3D =3D =3D
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    * Origin: Capitol City Online (1:2320/107)