• MESO: Mesoscale Discussion 1475

    From COD Weather Processor@1:2320/127 to wx-storm@lists.illinois.edu on Fri Jul 3 22:06:14 2026
    ACUS11 KWNS 032206
    SWOMCD
    SPC MCD 032205=20
    INZ000-ILZ000-WIZ000-IAZ000-040000-

    Mesoscale Discussion 1475
    NWS Storm Prediction Center Norman OK
    0505 PM CDT Fri Jul 03 2026

    Areas affected...Eastern Iowa into southern Wisconsin and northern
    Illinois

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

    Valid 032205Z - 040000Z

    Probability of Watch Issuance...40 percent

    SUMMARY...Convective trends are being monitored across eastern Iowa
    into southern Wisconsin and northern Illinois. Watch issuance is
    possible if further convective intensification and clustering can
    occur in the coming hours.

    DISCUSSION...Weak convection has been percolating along a residual
    outflow boundary across eastern IA and into southern WI/northwest IL
    over the past hour. Despite temperatures warming back into the 80s
    and dewpoints recovering into the 70s, prior convective overturning
    appears to be limiting the overall thermodynamic environment across
    this region, resulting in the anemic convective development observed
    so far.=20

    Further south, a more diffuse outflow boundary associated with a
    weak MCS currently over Lower MI is beginning to advance northward.
    Convective development in proximity to the boundary as well as
    notable boundary-layer cumulus along/south of the boundary hint that
    this demarcates the northern extent of the more buoyant/unstable air
    mass (characterized by MLCAPE values of 2000-3000 J/kg). It remains
    unclear how far north this boundary will progress through
    mid-evening, but it is conceivable that the more buoyant air mass
    will continue to spread north, eventually reaching the boundary
    draped across eastern IA and the IL/WI border. If this occurs,
    further intensification of convection will be possible, and
    downstream propagation across northern IL may occur. It is also
    possible that developing convection along the southern boundary
    continues to intensify and could pose a more transient and localized
    hail/wind risk in the coming hours. Confidence in either scenario is
    relatively limited, but trends are being monitored for the need for
    watch issuance this evening.

    ..Moore/Gleason.. 07/03/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6lHGwVExY6B9UuUz1yqXL7WmX594Wbcm4W82Mv6mNE3iFd8F--vkW54he2j_amtjzTpCkbdIZ= heNcAfwquvH77m4OQo$ for graphic product...

    ATTN...WFO...LOT...ILX...MKX...DVN...ARX...

    LAT...LON 41088825 41078973 41179094 41489178 41769188 42279196
    42659190 43009168 43149140 43189071 43138795 43018777
    42768776 42338776 42068761 41808743 41738743 41558740
    41258749 41108776 41088825=20

    MOST PROBABLE PEAK WIND GUST...55-70 MPH
    MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


    =3D =3D =3D
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    * Origin: Capitol City Weather Station (1:2320/127)