• MESO: Mesoscale Discussion 0001

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Wed Jan 3 03:28:26 2024
    ACUS11 KWNS 030327
    SWOMCD
    SPC MCD 030326=20
    CAZ000-030800-

    Mesoscale Discussion 0001
    NWS Storm Prediction Center Norman OK
    0926 PM CST Tue Jan 02 2024

    Areas affected...the Sierra Nevada...from west of Tahoe into areas
    southeast of Yosemite

    Concerning...Heavy snow=20

    Valid 030326Z - 030800Z

    SUMMARY...Heavy snow rates in excess of 2 inches per hour may begin
    impacting the I-80 corridor west of Tahoe by 9-10 PM PST, if not
    earlier, before developing southward along the western slopes of the
    Sierra Nevada, across and southeast of Yosemite by midnight-1 AM
    PST.

    DISCUSSION...Cloud tops have been cooling the past few hours, inland
    of the San Francisco Bay area toward the Sierra Nevada to the west
    of Tahoe. This is occurring downstream of a vigorous short wave
    trough, which is forecast to continue gradually pivoting across and
    inland of the central California coast through 06-09Z., accompanied
    by considerable further strengthening of large-scale ascent. Models
    indicate that strongest lift will focus along a frontal zone already
    in the process of advancing inland, south/east of the Bay area and
    into the northern Sierra Nevada, and within an increasing upslope
    flow component across the western slopes of the northern into
    southern Sierra Nevada by late evening.

    Coupled with saturating thermodynanmic profiles, including
    precipitable water in excess of .4 to .5 inches, strengthening lift
    through through mid-levels with favorable cold temperatures for
    large dendritic ice crystal growth (roughly between 700-600 mb in
    forecast soundings) appears likely to yield intensifying snow rates.
    By 05-06Z, if not before, guidance generally indicates that this
    may include rates in excess of 2 inches per hour near the Interstate
    80 corridor, where cold advection may result in snow levels falling
    to near or below 4000 feet.=20=20=20

    As the strengthening lift develops southward along the mountains
    into and southeast of the Yosemite vicinity through 08-09Z, snow
    levels are likely to be higher (on the order of 4500 to 5000+ feet),
    at least initially, before gradually falling overnight. However,
    somewhat higher moisture content may support heavier peak rates
    approaching or exceeding 3 inches per hour.

    ..Kerr.. 01/03/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4rfqvHZyalw5h4rC57JHmz6eJNoA87jMp6Ssec5Tqblhxb0ty9lwRQHyP3LLuODY9BWxkiTii= KttRf9dUrUTUu2nqeg$ for graphic product...

    ATTN...WFO...REV...HNX...STO...

    LAT...LON 39282034 38832002 38131950 37361936 37671975 38162027
    38772070 39082082 39282034=20


    =3D =3D =3D
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