100
ACUS01 KWNS 150528
SWODY1
SPC AC 150527

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 AM CDT Sun Jun 15 2025

Valid 151200Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
SOUTHEAST MONTANA AND FAR NORTHEAST WYOMING INTO PARTS OF THE
WESTERN DAKOTAS...

...SUMMARY...
Scattered severe storms capable of large to very large hail and
swaths of damaging gusts are possible across portions of Montana
into northeast Wyoming, and parts of the western Dakotas this
afternoon and evening. Additional strong to severe storms may occur
across the central/southern High Plains, and over parts of Virginia
and North Carolina.

...MT/WY into the Dakotas...

An upper ridge will be oriented over the Rockies/adjacent High
Plains vicinity today. However, a shortwave impulse is forecast to
eject through the top of the ridge during the late
afternoon/evening, providing some large-scale ascent and increasing
mid/upper westerly flow. In the low-levels, a surface
boundary/residual outflow from prior convection is forecast to be
oriented across south-central/southeast MT eastward along the ND/SD
border vicinity. East to southeasterly low-level flow will transport
mid 50s to low 60s F dewpoints along this boundary and to the east
of a lee surface trough extending southward across eastern WY/CO.
Strong surface heating and steep midlevel lapse rates will support
moderate to strong destabilization (2000-3500 J/kg MLCAPE).

One or more clusters of storms is forecast to develop over higher
terrain of central MT, southeastward into northeast WY. Supercell
wind profiles, with elongated/straight hodographs above 2-3 km
suggest initial cells over central into southeast MT will pose a
risk for large to very large hail (2+ inch diameter) in addition to
strong wind gusts. With time, clustering is expected and upscale
growth into an east/southeast progressing MCS/bow tracking along an
instability gradient/west-east surface boundary is forecast.
Damaging wind gusts, some potentially up to 80 mph, will be possible
once upscale development occurs. The east/southeast extent of
greater severe wind potential is a bit uncertain, however,
decreasing instability and increasing inhibition with eastward
extent should limit eastward progression into the eastern Dakotas
overnight.

...Central High Plains vicinity...

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

...Eastern NM into TX/OK/AR...

Convection will be ongoing across OK and western AR at the beginning
of the forecast period this morning. Gusty winds may accompany this
activity. Additional convection may develop or re-intensify as
outflow develops southward across portions of northwest/north TX as
stronger heating occurs by midday. Some potential exists that the
Marginal risk (level 1 of 5) may need to be expanded southward
across TX if a stronger forward propagating MCS can be maintained.
However, vertical shear is forecast to be weak and confidence in
robust, organized convection with southward extent is low.
Additional storms may develop across AR during the afternoon in the
vicinity of a potential eastward developing MCV. Isolated strong
gusts and may accompany this activity as well.

Additional isolated thunderstorms producing gusty winds and perhaps
hail may develop along the surface trough across eastern NM during
the late afternoon as well.

...VA/NC...

A mid/upper shortwave impulse will track east across the
central/southern Appalachians today. Meanwhile, a lee low is
forecast to track eastward near the NC/VA border through the
afternoon. A seasonally moist and unstable airmass will be in place
across the Piedmont into the coastal plain. Poor midlevel lapse
rates and weak vertical shear should limit overall severe potential,
but isolated wet microbursts or possibly marginal hail with stronger
updrafts pulses will be possible.

..Leitman/Supinie.. 06/15/2025

$$