218
ACUS03 KWNS 280730
SWODY3
SPC AC 280729

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 AM CDT Fri Jun 28 2024

Valid 301200Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MT
INTO WESTERN ND...AND ALSO FROM THE MID ATLANTIC INTO
SOUTHERN/EASTERN NEW ENGLAND...

...SUMMARY...
Scattered damaging winds are possible across parts of the Mid
Atlantic and Northeast on Sunday. Hail and severe gusts will also be
possible from eastern Montana into western North Dakota.

...Carolinas into the Northeast...
A seasonably deep and positively tilted trough is forecast to move
southeastward across the Northeast and Mid Atlantic on Sunday. A
surface low will move from eastern Quebec into the Canadian
Maritimes, as a trailing cold front moves across parts of the
eastern CONUS. Weak midlevel lapse rates could limit prefrontal
destabilization to some extent across parts of the Northeast/New
England, but potentially strong diurnal heating and sufficient
deep-layer shear could result in scattered strong storms capable of
scattered damaging wind and possibly some hail during the
afternoon/evening.

Guidance continues to vary somewhat regarding timing of the front. A
Slight Risk has been included from parts of the Mid Atlantic into
New England, where organized damaging-wind potential appears most
possible at this time. Some adjustments will likely be needed,
depending on trends regarding timing of the front and prefrontal
destabilization.

Farther south, somewhat stronger destabilization will be possible
into the Carolinas, within a very moist environment. Mid/upper-level
flow will be weaker, but modest west-northwesterlies aloft could
support some stronger cells/clusters capable of at least isolated
damaging wind.

...Montana into the western Dakotas...
A mid/upper-level trough is forecast to move from the Northwest
across northern Rockies during the day on Sunday, with some
influence of the trough expected to spread into the northern High
Plains by Sunday evening. A surface low is expected to deepen across
northern WY, with low-level moisture return expected east and north
of the low into parts of Montana and the western Dakotas.

At least modest diurnal destabilization will be possible from
southwest into central MT, with moderate buoyancy potentially
developing farther east into parts of eastern MT and the western
Dakotas. Guidance still varies somewhat regarding timing of stronger
ascent across the region, but storm development will be possible
across western into central MT during the afternoon. These storms
may move eastward with time, with other isolated development
possible by early evening into eastern MT.

Increasing deep-layer shear will support organized convection, and a
few stronger clusters and/or supercells will be possible, with a
threat of hail and severe gusts. An MCS may develop Sunday night and
move into western/central ND, as a low-level jet nocturnally
strengthens. The severity of any MCS will be more uncertain with
eastward extent, due to increasing low-level stability. However,
some threat for severe gusts could spread across western and
possibly central ND.

Storm development/coverage is more uncertain farther south, but with
the environment expected to become conditionally favorable by late
afternoon into the evening, a strong/severe storm or two will also
be possible into western SD.

...CO Front Range into the central High Plains...
In the wake of a cold frontal passage, low-level moisture will
stream westward into the CO Front Range vicinity and adjacent
central High Plains, with the western extension of the boundary
expected to lift northward as a warm front through the day. Moderate
destabilization will be possible during the afternoon, with
potential for at least isolated storm development. Midlevel flow
will likely remain weak to modest, but sufficient veering with
height could support organized multicell clusters and perhaps a
supercell or two, with a threat of hail and severe gusts.

...South-central Great Plains into the Southeast and TN Valley...
A cold front is forecast to move into parts of the south-central
Great Plains and Ozark vicinity Sunday morning, potentially
accompanied by ongoing convection. Moderate to locally strong
buoyancy may develop along/south the front during the afternoon, in
areas that are not as influenced by early-day convection. Midlevel
flow will likely remain weak, but may take on a more northerly
component later in the day, which could provide sufficient
deep-layer shear for briefly organized storms. Given the rather
weakly sheared environment and uncertainty regarding the favored
frontal corridor, no probabilities have been included for this
regime at this time.

..Dean.. 06/28/2024

$$