Mesoscale Discussion 1119
NWS Storm Prediction Center Norman OK
0311 AM CDT Thu Jun 22 2017
Areas affected...Portions of the northern Plains
Concerning...Severe potential...Watch unlikely
Valid 220811Z - 220915Z
Probability of Watch Issuance...20 percent
SUMMARY...A few intensifying thunderstorms early this morning may be
capable of isolated instances of large hail, and perhaps a few
stronger gusts. However, the threat is currently expected to remain
limited enough to preclude watch issuance.
DISCUSSION...On the southern fringe of a mid/upper jet maximum,
isolated/widely scattered thunderstorms have developed early this
morning. Recent Aberdeen, SD (KABR) VWP data exhibit westerly
mid-level flow around 50-60kt, with resultant deep-layer shear
sufficient for updraft organization/rotation. Therefore, as these
cells move east into more substantial mid-level buoyancy (e.g.,
MUCAPE around 1000-2000 J/kg), they may be capable of isolated large
hail reports. Moreover, despite being rooted above the surface
(likely near 700mb), pockets of sufficient low-level temp/dew point
spreads may support occasional strong, gusty surface winds. This
threat will be further enhanced by small bowing segments resulting
from somewhat uni-directional flow in the convective layer.
Nonetheless, any severe threat is currently expected to remain
spatially limited, likely precluding overnight watch issuance.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 44000089 44280097 44770004 45259662 45249473 45069418
44459395 44009406 43729504 43459636 43289751 43299912
43370028 43880088 44000089