• MESO: Mesoscale Discussion 0143

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Thu Feb 9 15:49:17 2023
    ACUS11 KWNS 091549
    SWOMCD
    SPC MCD 091548=20
    WIZ000-ILZ000-IAZ000-091945-

    Mesoscale Discussion 0143
    NWS Storm Prediction Center Norman OK
    0948 AM CST Thu Feb 09 2023

    Areas affected...Eastern Iowa into southwest Wisconsin

    Concerning...Heavy snow=20

    Valid 091548Z - 091945Z

    SUMMARY...Periods of moderate to heavy snow will persist through
    early afternoon across eastern Iowa into southwest Wisconsin as
    low-level evaporative cooling allows for a transition from rain to
    snow.

    DISCUSSION...Web cams from across eastern IA and southwest WI show
    areas of heavy snowfall with visibility reductions down to 1/2 to
    1/4 mile, and recent LSRs from the region report quick snowfall
    accumulations between 1-1.5 inches over the past 1-2 hours under a
    concentrated snow band. These observations are supported by recent
    ASOS reports of similar visibility reductions concurrent with
    moderate to heavy snowfall as temperatures fall to near 32 F under
    the band. Recent radar trends from KDVN show a weakening trend in
    the ongoing band; however, strong ascent associated with the passage
    of an upper wave, combined with more focused mesoscale ascent driven
    by low-level isentropic ascent and frontogenetical lift in the
    850-700 mb layer, is expected to persist well into the afternoon as
    the system lifts to the northeast, maintaining the potential for
    additional heavy snow bands.

    While most locations remain above freezing, strong evaporative
    cooling coincident with the heaviest precipitation will allow for a
    transition from rain/wintry mix to moderate/heavy snow with snowfall
    rates between 1-2 inches per hour. Although the most intense
    snowfall rates will likely be concentrated spatially, additional
    visibility reductions and snow accumulations are possible if/where
    additional snow bands develop through the afternoon.

    ..Moore.. 02/09/2023

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9VBQjseb3GRg-qtALtKyJvOsIJstnqKTgyoDJRBwPvORj4IyVjWMJeeY5uHvVT0P-GRR3g1o1= hv9r7oJSwsh_YIAJJA$ for graphic product...

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

    LAT...LON 41109207 41829209 42459171 42969096 43159049 43309004
    43328963 43108924 42808908 42618915 42388939 41989018
    41639074 41249104 40969118 40849136 40819165 40869199
    41109207=20


    =3D =3D =3D
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