911
ACUS01 KWNS 140535
SWODY1
SPC AC 140534

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 AM CDT Sun Jul 14 2024

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...
Strong to severe thunderstorms are expected from the northern Plains
into the Upper Midwest.

...Northern Plains to Upper Midwest...

Large-scale pattern is not expected to change appreciably during the
day1 period, though some amplification is possible later in the
week. Upper high is forecast to remain anchored in the Four Corners
vicinity while seasonally strong mid-level flow will hold along a
corridor near the US/Canadian border. Negligible height changes are
expected during the first half of the period, though a few notable
short waves will track east-southeast from southern AB/SK into the
Great Lakes. Each short-wave trough should encourage convective
development -- some of it will likely be severe.

Early this morning, a weak MCS was propagating southeast across
northern IL/southern Lake MI. This activity is supported by a weak
disturbance and should progress into the southern Great Lakes/OH
Valley later today. Diurnal heating will contribute to strong
buoyancy, and robust updrafts may evolve along the leading debris
field by mid day. Locally severe winds may develop if convection
reintensifies.

Of more concern will be convection that develops across the northern
Plains later in the afternoon. A strong short-wave trough will dig
southeast across southern AB by 15/00z before translating into
MB/eastern Dakotas by the end of the period. It appears a weak
surface low should evolve ahead of this feature over eastern MT
early, then shift into central SD by peak heating. A
northwest-southeast corridor of low-level warm advection will extend
across the Dakotas north of a synoptic boundary that will be draped
from southern MN-central SD-northeast MT. Strong boundary-layer
heating will negate CINH across the High Plains such that isolated
convection should develop by 22z. This activity will mature and grow
upscale through the evening. Early storm mode should be
supercellular, then clustering will lead to an MCS that is expected
to track southeast toward the mid MO Valley. Very steep lapse rates
will lead to strong buoyancy, and potentially very large hail
(possibly in excess of 2 inches). Very strong winds (>70mph) may
also be noted along the leading edge of the surging MCS.

..Darrow/Moore.. 07/14/2024

$$