Areas affected…East-Central SD…Southern MN…North-Central IA
Valid 090716Z – 091215Z
SUMMARY…A band of heavy snowfall with rates from 1″ to 2″ per hour
will gradually shift eastward across east-central SD, southern MN,
and far north-central IA over the next few hours.
DISCUSSION…Recent mesoanalysis reveals a broad low-level jet
extending from central TX into far southeast SD/far northwest IA.
This low-level jet is contributing to strong warm-air advection and
low to mid-level frontogenesis from southeast SD eastward across
much of IA. This strong mesoscale forcing for ascent has resulted
the development of a band of heavy snowfall (i.e. snowfall rates at
or above 1″ per hour). Regional radar imagery shows this band
extending from east-central SD southwestward across southern MN and
into far northern IA.
Expectation is for this band to gradually shift eastward over the
next several hours in step with mid-level trough responsible for the
low-level jet. Snowfall rates above 1″ per hour will be common
within this band, with instances of rates near 2″ per hour also
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 43719587 44319832 44919735 45079602 44799441 44479342
44029288 43669284 43189332 43359484 43719587