804
ACUS02 KWNS 191732
SWODY2
SPC AC 191730

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Thu Sep 19 2024

Valid 201200Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
MIDWEST AND ALSO THE SOUTH-CENTRAL PLAINS...

...SUMMARY...
Isolated strong to severe thunderstorms are possible in the late
afternoon Friday in parts of Illinois, Indiana, and southwest Lower
Michigan. Isolated strong to severe storms are also possible across
parts of the south-central Plains.

...Midwest...
A low-amplitude shortwave trough will pass across the Upper to
central Great Lakes during the first half of the period. This will
outpace a cold front that trails from a cyclone shifting northeast
in MB, yielding a largely weakening to stalling front by Friday
evening. Most guidance suggests at least isolated thunderstorms
should form within a low-level warm conveyor ahead of the front,
generally focused on a moderate buoyancy plume emanating northeast
from parts of MO/AR. A fast westerly upper jet will further impinge
on this portion of the front as well, favorably timed with peak
boundary-layer heating. A few marginally severe storms may develop
within this regime. Despite weak mid-level lapse rates, elongation
of the mid to upper hodograph should support a threat for 1-1.5 inch
hail, along with strong to marginally severe gusts from 45-60 mph.
These threats should diminish quickly after sunset.

...Southern KS/northern OK vicinity...
A mid/upper-level shortwave trough is forecast to move slowly
eastward across the Southwest on Friday. Farther east, a surface
boundary initially draped from the lower MO Valley into southern
KS/northern OK is forecast to lift northward as a warm front.
Large-scale ascent across much of the Plains may remain relatively
limited, outside of low-level warm advection near/north of the
front. However, relatively strong heating along the western/northern
periphery of returning low-level moisture could support thunderstorm
development during the afternoon somewhere in the vicinity of
southwest KS/northwest OK. Effective shear of 30-40 kt will support
potential for somewhat organized convection. Strong to localized
severe gusts may be the most likely hazard, but hail cannot be ruled
out if any more discrete storms can move into an environment of
greater moisture/instability.

...New Mexico...
Scattered thunderstorms will be possible across much of NM on
Friday, in closer proximity to the approaching shortwave trough.
While deep-layer shear will be rather strong, generally weak
midlevel lapse rates and buoyancy may tend to limit the potential
for more robust storms. If confidence increases regarding sufficient
heating/destabilization, then severe probabilities may eventually be
needed for parts of the region.

...Central Plains into the lower MO Valley...
Guidance continues to vary regarding the potential for robust
elevated convection Friday night into Saturday morning, within a
low-level warm advection regime. Increasing elevated buoyancy and
sufficient mid/upper-level flow could support a few stronger storms
with hail potential, but confidence in sufficient coverage and a
favored region for this potential is too low for probabilities at
this time.

..Dean.. 09/19/2024

$$