000
ACUS11 KWNS 242049
SWOMCD
SPC MCD 242049
SDZ000-NEZ000-242215-

Mesoscale Discussion 1416
NWS Storm Prediction Center Norman OK
0349 PM CDT Mon Jul 24 2017

Areas affected...portions of north-central Nebraska and central
South Dakota

Concerning...Severe potential...Watch unlikely

Valid 242049Z - 242215Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms are expected to develop/intensity this
afternoon and slowly move east. Hail and strong thunderstorm winds
will be possible with some of the thunderstorms. The isolated nature
of the threat should preclude the need for a severe thunderstorm
watch.

DISCUSSION...A thunderstorm has developed in northern Jones County,
South Dakota, near the apex of surface-based instability and
decreasing convective inhibition. This region is on the southwest
flank of an eastward moving mesoscale convective vortex (MCV)
located in the vicinity of the North Dakota/South Dakota border.
Modest low-level convergence/forcing for ascent associated with the
MCV, coupled with continued heating and decreasing convective
inhibition should lead to the development of additional isolated,
thunderstorms this afternoon.

The larger-scale environment is characterized by surface-based CAPE
between 2000-3500 J/kg and deep-layer shear values between 35-50
knots, which should support a couple supercells. Surface
temperatures in the mid-to-upper 90s and dewpoints in the low 60s
should yield fairly high-bases on these thunderstorms. Hail and
strong winds should be the primary hazards.

..Marsh/Grams.. 07/24/2017

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

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON   42810219 44250095 44999985 44849870 44379864 43909884
            43509929 42740178 42810219