Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0244 PM CDT Wed May 14 2025
Valid 142000Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
NORTHERN/CENTRAL PLAINS...
...SUMMARY...
Scattered strong to severe thunderstorms should occur over parts of
the Dakotas and Nebraska this afternoon and evening, and far western
Iowa and southwest Minnesota overnight. Very large hail, severe wind
gusts, and a couple of tornadoes all appear possible.
...20z Update...
No changes are needed to the D1 Convective Outlook.
Severe storms are expected across the northern/central Plains this
afternoon and evening as an upper low moves eastward with a surface
cold front. Latest data from 18z RAOBs across Nebraska shows weak
mid-level capping still in place across the area near North Platte,
which much stronger MLCIN further east near Omaha. Ongoing elevated
post frontal convection will continue before further convective
development occurs later this afternoon and evening. These storms
will have potential for very large hail, damaging wind, and a couple
of tornadoes. See MCD#777 for more information on this threat in the
near term.
See previous discussion for more information below.
..Thornton/Gleason.. 05/14/2025
.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed May 14 2025/
...Northern/Central Plains...
An upper trough over the western states will pivot eastward today
while gradually acquiring a negative tilt over the northern/central
Plains by late tonight. At the surface, a front extending over the
Dakotas should stall in a nearly north-south orientation later
today. Shallow low-level moisture will continue to stream northward
this afternoon ahead of the primary surface low, which is forecast
to consolidate over western KS/southwest NE by early evening. A
dryline will extend southward from this low over much of the
central/southern Plains, but strong capping should generally limit
convective development with southward extent through much of the
day.
Daytime heating of the modestly moist low-level airmass, combined
with somewhat steepened mid-level lapse rates, will encourage around
1500-3000 J/kg of MLCAPE by mid afternoon. Stronger instability will
likely exist with southward extent into NE, where slightly greater
low-level moisture should be present. Mainly unidirectional/
southerly wind profiles along/near the front this afternoon suggest
that initial convective development will be messy, with numerous
updraft and outflow interactions. Still, the strongest of these
initial cores should pose some risk for hail and wind gusts.
Initially high-based convection is also forecast to develop across
the central High Plains (northeast CO vicinity) by late
afternoon/early evening, and spread northeastward across NE. A
greater threat for sustained supercells remains apparent with
southward extent across NE this evening, where stronger deep-layer
shear somewhat more orthogonal to the surface boundaries should be
present. Isolated very large hail (up to 2-3 inches in diameter)
will be possible with any discrete cells, while severe wind gusts
should become an increasing concern as convection grows upscale into
a bowing cluster through the evening and early overnight hours.
There should also be a narrow spatial/temporal window for a couple
of tornadoes this evening across parts of NE as a low-level jet
modestly strengthens and 0-1 km SRH increases.
...Southeast and Southern Mid-Atlantic into the Ohio Valley...
A weak mid/upper trough will drift eastward today from the
Appalachians towards the Carolinas and Mid-Atlantic. While mid-level
winds and related effective bulk shear are expected to remain rather
weak, some clustering/modest organization may occur with convection
that will further develop this afternoon across NC into parts of
southern VA. Occasional damaging winds should be the main threat
with this activity as low-level lapse rates gradually steepen with
continued diurnal heating. But, some hail may also occur. See
Mesoscale Discussion 776 for more details on the short-term severe
threat across this area.
Across parts of the OH Valley, mainly elevated thunderstorms are
forecast to develop this evening/overnight in a low-level warm
advection regime. Sufficient MUCAPE and deep-layer shear is forecast
to support an isolated threat for mainly large hail with this
activity.
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