Mesoscale Discussion 1325
NWS Storm Prediction Center Norman OK
0336 PM CDT Sun Jul 16 2017
Areas affected...Parts of the northern Rockies and northern High
Concerning...Severe potential...Watch unlikely
Valid 162036Z - 162230Z
Probability of Watch Issuance...20 percent
SUMMARY...Thunderstorms will continue to develop across parts of the
region this afternoon. Isolated severe/damaging gusts and marginally
severe hail will be possible. However, the threat should remained
sufficiently isolated/disorganized to preclude watch issuance.
DISCUSSION...Along the fringe of a subtle impulse within
southwesterly flow aloft, strengthening terrain circulations have
promoted isolated to widely scattered thunderstorms this afternoon.
Surface temperatures in the 80s/90s, coupled with adequate
boundary-layer moisture, have resulted in MLCAPE values around
500-750 J/kg -- sufficient for a few more vigorous updrafts.
Associated with these more intense cells, downward transfer of
stronger flow aloft, as well as ample evaporative cooling within a
deep/well-mixed boundary layer, will be favorable for a few
strong/severe gusts. Moreover, effective shear of 30-40 kt, and
non-trivial CAPE within the preferred hail-growth zone, may support
isolated instances of marginally severe hail through the evening
hours. Nonetheless, a lack of more substantive organization should
preclude the need for a watch.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 44661210 47230924 47790721 47890551 47740499 47020438
46190456 45140557 44550791 44080990 43811081 43771109