Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1237 AM CDT Thu Aug 15 2024
Valid 151200Z - 161200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN KS
INTO PARTS OF THE MID MS VALLEY AND MIDWEST...
...SUMMARY...
Scattered severe thunderstorms are possible across parts of the
Midwest, mid Mississippi Valley, and central Plains on Thursday.
Damaging winds and large hail should be the main threats, but a
couple tornadoes may also occur. A few strong storms may also
develop across parts of the Northeast.
...Central Plains to the Mid Mississippi Valley...
Weak mid-level height falls will spread across the mid Mississippi
Valley today ahead of a short-wave trough that will approach western
IA/northwest MO by early evening. Early in the period, a weak
short-wave trough will be responsible for inducing multiple
thunderstorm clusters across the Midwest, aided by LLJ that will
translate into Lower MI by late afternoon. This early-day convection
will be an extension of ongoing thunderstorm clusters that currently
extend from central IA into eastern KS. This activity will propagate
downstream as the LLJ shifts into the Great Lakes ahead of the weak
disturbance. While locally severe gusts and hail could accompany
this activity, considerable amount of precip and modest lapse rates
do not favor widespread severe.
Of more concern, strong boundary-layer heating is expected across
much of the Plains into portions of the mid MS Valley. As a result,
strong buoyancy will develop along the eastern edge of this steeper
lapse-rate plume. Latest model guidance suggests very strong
instability (MLCAPE >3000 J/kg) will materialize by mid afternoon
from portions of eastern KS/MO into southeast IA. High-level
diffluent flow will favor storm-top venting and scattered robust
thunderstorms are expected to develop ahead of the short wave.
Thunderstorms should concentrate along a synoptic front that will
arc from southeast MN-eastern IA-northern MO-southeast KS-northern
OK by late afternoon. Deep-layer shear should be adequate for
supercells and wind/hail can be expected with the most robust
updrafts. High-based thunderstorms are also expected to develop
along the trailing boundary into the southern Plains where surface
temperatures will easily rise through the upper 90s to near 100F.
Dry adiabatic 0-3km lapse rates favor strong downdrafts as PW values
will be seasonally high (1.5-1.75 inches).
...New England region...
Upper troughing will hold across New England today with cool
mid-level temperatures and modest northerly flow at 500mb. Strong
boundary-layer heating will allow convective temperatures to be
breached by 19z and scattered convection is expected to develop
within a sheared environment that favors robust multi-cell updrafts.
Some of this activity could generate strong gusts and marginally
severe hail. Convection will be diurnally driven and should weaken
with loss of daytime heating.
..Darrow/Halbert.. 08/15/2024
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