388
ACUS01 KWNS 271935
SWODY1
SPC AC 271933

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0233 PM CDT Thu Jun 27 2024

Valid 272000Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN AND CENTRAL PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
UTAH AND WESTERN COLORADO...

...SUMMARY...
The greatest severe-thunderstorm threat is over parts of the
northern/central High Plains this afternoon and evening, where very
large hail, significant damaging winds, and a few tornadoes are
possible.

...Eastern Carolinas/GA...

The Marginal (level 1 of 5) risk has been trimmed from central GA
and portions of the Carolinas based on latest observations/ongoing
convection and the location of the surface trough. Sporadic strong
gusts remain possible into early evening.

...Northern/Central Plains...

The Marginal (level 1 of 5) risk has been trimmed across parts of
southwest/west-central MT based on the current location of the upper
trough and convection developing over the higher terrain shifting
eastward. Meanwhile, the Enhanced (level 3 of 5) risk has been
trimmed across a small part of northern ND. Persistent cloud cover
has limited heating/destabilization across this area, and surface
dewpoints are lower, in the upper 50s to near 60 F.  Current cloud
cover is not expected to lift north/east very quickly. A
differential heating boundary across western ND will likely serve as
an effective warm front, with convection moving east of this
boundary during the evening gradually weakening with time across
central ND.

Otherwise, overall forecast philosophy remains unchanged from the
previous outlook, and no changes have been made to the outlook
across the central/southern Plains vicinity. See prior discussion
below, or reference MCD 1445 and severe thunderstorm watch 473 for
more information.

...Eastern Great Basin...

No changes have been made to the outlook across this region. See
previous discussion below, or reference MCD 1446 and severe
thunderstorm watch 474 for more information.

..Leitman.. 06/27/2024

.PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 27 2024/

...Western MT into Eastern Great Basin...
Morning water vapor loop shows an impressive shortwave trough
rotating across the northwest states.  This feature will result in
strengthening winds aloft across much of the Great Basin and
northern Rockies today, along with increasing large scale forcing
for ascent.  This will lead to scattered thunderstorms over the
higher terrain of western MT into parts of WY/CO/UT by early
afternoon.  Forecast soundings show sufficient westerly flow/shear
through the cloud-bearing layer to support organized and
occasionally supercell storms capable of hail and damaging wind
gusts.

...Eastern MT into the Dakotas...
As convection spreads off the higher terrain into eastern MT, storms
will encounter greater low level moisture/shear, further promoting
supercell structures and the risk of very large hail and perhaps a
few tornadoes.  These storms will progress eastward through the
afternoon/evening into the Dakotas, where upscale growth into bowing
structures is anticipated - capable of significant damaging winds.

...Central Plains...
Farther south, forcing will be weaker and convective coverage should
be less.  However, convection will intensify as outflows from the
High Plains spread eastward into the moist axis, with a combination
of bowing and supercell storms expected.  Damaging winds are
probably the main risk, but substantial low level and deep layer
shear could support large hail and a tornado or two in this region
as well.

...Carolinas/GA...
A very moist and unstable air mass is present today from
central/eastern NC southwestward into eastern GA.  Scattered mid and
high clouds will somewhat mitigate afternoon heating.  But a few
strong/severe storms are expected, with water-loaded downdrafts
capable of locally damaging wind gusts.

$$