481
ACUS11 KWNS 150904
SWOMCD
SPC MCD 150904
MNZ000-IAZ000-SDZ000-151030-

Mesoscale Discussion 0784
NWS Storm Prediction Center Norman OK
0404 AM CDT Thu May 15 2025

Areas affected...Parts of eastern SD into southwest MN and far
northwest IA

Concerning...Severe Thunderstorm Watch 250...

Valid 150904Z - 151030Z

The severe weather threat for Severe Thunderstorm Watch 250
continues.

SUMMARY...An isolated severe threat may spread northeast out of WW
250 with time this morning.

DISCUSSION...A long-lived storm cluster has evolved into a bowing
MCS (with embedded cellular elements) from far eastern SD into
southwest MN, and strong to locally severe gusts have been reported
over the last hour to the northeast of Sioux Falls, SD. Small
mesovortices have occasionally been noted along the leading edge of
the line, and a threat for localized severe gusts could be maximized
with these features, especially where the outflow has not surged
ahead of the deeper convection.

The northern portion of the line will tend to move into a cooler and
less unstable environment with time, though more substantial
moisture return above the surface could maintain robust elevated
convection through the early morning. The southern portion of the
line will be in closer proximity to increasing MLCAPE and weaker
MLCINH, though lingering near-surface stability may hamper
reintensification potential.

An isolated severe threat may spread northeast out of WW 250 with
time, though the need for downstream watch issuance is uncertain.

..Dean/Bunting.. 05/15/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MPX...DMX...FSD...ABR...

LAT...LON   44179616 45139736 45729686 45619575 45459489 45319442
            45059420 44679403 44419403 43999424 43239470 42899540
            42889580 43099623 44179616

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN