SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0743 PM CDT Thu Aug 25 2022
Valid 260100Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING
NEAR THE BLACK HILLS AND ADJACENT PLAINS...AND ACROSS WESTERN
MONTANA...
...SUMMARY...
Strong storms may continue to impact parts of the Black Hills and
adjacent high plains, as well as parts of the Montana Rockies, into
this evening, accompanied by at least some risk for severe storms.
...01Z Update...
Within weak (10-20 kt) westerly deep-layer ambient mean flow,
broad/weak troughing, with an embedded mid-level low, will continue
to gradually shift eastward across the northern Intermountain
Region/Rockies. Preceding the main low, a smaller scale cyclonic
vorticity center/lobe is slowly approaching the Black Hills
vicinity. This feature is translating eastward along the
northeastern periphery of a plume of warm elevated mixed-layer air
nosing east of the Wyoming/Colorado Rockies, with weak lower/mid
tropospheric warm advection now generally focused across the Black
Hills and adjacent plains.
Relatively moist easterly low-level flow to the cool side of a zone
of stronger differential surface heating, beneath the edge of the
elevated mixed-layer air, has contributed to a corridor of
moderately large mixed-layer CAPE (up to 2000 J/kg). This is
supporting scattered vigorous thunderstorms across eastern Wyoming,
from near Gillette into areas east of Douglas. While the deep-layer
mean flow is weak, pronounced veering from easterly and
southeasterly to westerly with height is contributing to shear at
least marginally sufficient for supercells. And ongoing storms may
maintain strength another couple of hours, slowly spreading eastward
toward the Black Hills. Aided by the large-scale forcing for
ascent, there appears some potential for convection to consolidate
into a slowly organizing cluster which could be accompanied by a few
strong surface gusts before weakening later tonight.
Otherwise, a few stronger to occasionally severe storms may maintain
strength another couple of hours, near/beneath the primary mid-level
thermal trough across the higher terrain of western Montana, before
the loss of daytime heating and eastward progression of the
mid-level impulse contribute to weakening trends by late evening.
..Kerr.. 08/26/2022
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SXG3JV
