361
ACUS01 KWNS 151253
SWODY1
SPC AC 151252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Sun Jun 15 2025

Valid 151300Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...

...SUMMARY...
Scattered severe thunderstorms capable of producing large to very
large hail and swaths of severe/damaging gusts (some 75+ mph) are
likely across portions of central/eastern Montana into northeast
Wyoming and the western Dakotas this afternoon through tonight.
Additional strong to severe thunderstorms may occur across the
central/southern Plains, and over parts of Virginia and North
Carolina.

...Northern/Central Plains...
Ongoing thunderstorms across northeast MT may pose an isolated hail
threat this morning. Otherwise, upper ridging will continue to
prevail over the Southwest and southern Rockies today, with a subtle
mid-level shortwave trough forecast to advance northeastward across
the northern Rockies and adjacent High Plains through the period.
This feature will likely aid in the development of initially
high-based convection over parts of the northern Rockies in MT by
early to mid afternoon. Meanwhile, diurnal heating of a fairly moist
low-level airmass (surface dewpoints generally in the mid to upper
50s) and steep mid-level lapse rates will foster around 2000-3000
J/kg of MLCAPE through the afternoon across much of central/eastern
MT along and south of a convectively reinforced boundary. Modest
low-level east-southeasterly flow will veer to west-southwesterly
and strengthen with height through mid/upper levels. This will
support around 40-50 kt of effective bulk shear and organized
convection.

Intense thunderstorm development appears increasingly likely across
central MT by mid to late afternoon, as large-scale ascent
associated with the shortwave trough overspreads the surface warm
sector. Given the rather favorable thermodynamic/kinematic
environment expected, initial convection will likely be
supercellular and pose a threat for large to very large hail
potentially up to 2-3 inches in diameter. The Enhanced Risk has been
expanded westward some in central MT to account for this expected
supercell development, and a 30% area has been included for large
hail as well. With time this evening, one or more clusters will
likely evolve from the initially discrete activity across eastern MT
into parts of northeast WY and the western Dakotas. Steepened
low-level lapse rates should aid in efficient mixing of intense
downdraft winds to the surface, and swaths of severe/damaging winds
should occur as thunderstorms spread eastward through the evening
and into early Monday morning. Some of these winds may be
significant, with peak gusts potentially reaching up to 70-80 mph on
an isolated basis.

Isolated to scattered high-based thunderstorms should develop along
the surface trough/dryline within a moist low-level upslope flow
regime across portions of southeast WY into eastern CO, and perhaps
persisting into western NE/KS. This activity will pose a risk of
strong to severe outflow winds given a deeply mixed boundary layer
and the presence of very steep low-level lapse rates. Isolated hail
may also occur where any robust updrafts can be maintained within a
modestly sheared environment.

...Southern Plains...
Extensive, loosely organized convection is ongoing this morning
across much of western/southern OK and vicinity. This activity is
being aided by modest low-level warm moist advection associated with
a 20-30 kt southwesterly low-level jet. Current expectations are for
these thunderstorms to generally weaken through the rest of the
morning as the low-level jet gradually weakens. Even so, an isolated
threat for strong/gusty winds may persist with these clusters as
they spread generally south-southeastward. There may be some chance
for either this morning convection or related outflow to regenerate
new, robust convection this afternoon across parts of TX. Have
expanded the Marginal Risk for wind southward a bit to account for
this potential, but in general weak shear should limit convective
organization with southward extent. Otherwise, an isolated severe
threat may exist with convection that develops across AR this
afternoon in proximity to a remnant MCV, and along/east of the
surface lee trough/dryline across the southern High Plains.

...Virginia/North Carolina...
A low-amplitude mid-level shortwave trough will move eastward across
the central/southern Appalachians today. A related weak surface low
should develop eastward near the NC/VA border through the afternoon.
A moist and unstable airmass will likely be in place across much of
NC and southern VA as filtered daytime heating occurs. Poor lapse
rates aloft and modest deep-layer shear should limit the overall
severe potential across this region. Still, isolated wet microbursts
and/or marginally severe hail may occur with the stronger
updrafts/cores that can develop this afternoon and early evening.

..Gleason/Kerr.. 06/15/2025

$$