423
ACUS48 KWNS 070844
SWOD48
SPC AC 070842

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0342 AM CDT Mon Jul 07 2025

Valid 101200Z - 151200Z

...DISCUSSION...
The Southwest upper ridge will gradually flatten as a more
progressive mid-level flow regime becomes established over the
northern CONUS later this week into early next week. Multiple
pronounced mid-level troughs, with cooler temperatures aloft, will
traverse the north-central U.S. and overspread rich low-level
moisture. Strong buoyancy will precede these troughs, and upon
lifting of this unstable airmass, at least scattered organized
thunderstorm development should ensue, with multiple rounds of
strong to severe storms possible.

...Day 4 (Thursday) - Northern Plains...
The first in a series of mid-level troughs will eject into the
northern Plains on Day 4/Thursday, encouraging surface lee troughing
across the central and northern Plains. Dewpoints into the 70s F,
beneath 8+ C/km mid-level lapse rates, will support strong to
locally extreme instability by afternoon peak heating. The ejection
of the upper trough will provide enough upper support for scattered
thunderstorm development. Increasing westerly flow with height will
result in straight, elongated hodographs. Supercells should be the
main mode of convection, at least initially, with severe wind and
hail the primary threats.

...Days 5-6 (Friday-Saturday) - Midwest toward the Great Lakes...
The main mid-level trough will continue to slowly approach the Upper
MS Valley as a preceding mid-level impulse continues to advance
eastward. Potential exists for renewed thunderstorm development for
portions of the Upper MS Valley and Midwest on Friday, spreading
east with upper trough advancement toward the Great Lakes on
Saturday. Rich low-level moisture beneath steep mid-level lapse
rates will promote strong instability in the warm sector, amid
modest vertical wind shear. Somewhere in this region, strong to
severe storms are likely, with severe wind/hail the main concerns on
both Friday and Saturday. The timing and location of thunderstorm
initiation will be highly dependent on the position of remnant
outflow boundaries from storms during previous days. Such details
are quite challenging to point out this far in advance, precluding
severe probabilities at this time, though probabilities will likely
be needed in future outlooks.

...Days 7-8 (Sunday-Monday) - Upper Mississippi Valley...
The next in a series of mid-level troughs will traverse the
north-central CONUS toward the end of the period. Medium-range
guidance consensus depicts extreme instability (i.e. well over 4000
J/kg MLCAPE) preceding this trough, along with strong enough
westerly mid-level flow and accompanying vertical wind shear. As
such, another episode of organized severe storms is possible in the
Sunday/Monday time-frame. However, given the seasonal weak forcing
associated with this second low-amplitude trough, run-to-run
guidance consistency is desired before severe probabilities are
delineated.

..Squitieri.. 07/07/2025