ACUS01 KWNS 301306
SWODY1
SPC AC 301304

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0804 AM CDT Tue Jul 30 2024

Valid 301300Z - 311200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE MISSOURI VALLEY/MIDWEST...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN/CENTRAL PLAINS TO THE SOUTHEAST...

...SUMMARY...
Severe storms are expected today into tonight across a broad area
from eastern Nebraska and Iowa into parts of the Midwest, Tennessee
Valley and southern Appalachians, with swaths of damaging winds
possible within this corridor. Severe storms are also possible
across parts of the northern Plains.

...Central Plains/Upper Midwest to OH/TN Valleys...
Very challenging meteorological scenario with highly variable
guidance as far as MCS development/disposition today. However, a
rather favorable set of ingredients will generally coincide,
spanning east/northeast Nebraska into Iowa, northern Missouri and
western Illinois, and to some extent even farther southeastward into
the Tennessee Valley. Very strong buoyancy will exist within this MCS/outflow-reinforced corridor, with a strong elevated mixed layer
-- yet not overly warm aloft for the season -- atop a moist boundary
layer. Seasonally strong west-northwesterly winds aloft will also
reside in this general corridor, with potential for multiple east/southeastward-moving MCSs today and tonight. Swath of damaging
wind gusts (potentially in excess of 75 mph) are plausible.

With a remnant thunderstorm cluster across Illinois, some
re-intensification of this convection may occur across the lower
Ohio Valley toward the Tennessee Valley, with a modestly strong
northwesterly flow regime and ample downstream instability. Isolated
to scattered damaging wind should be the primary threat.

Meanwhile, multiple thunderstorm clusters across Siouxland this
morning from southeast South Dakota into northwest/western Iowa may
continue to pose a severe risk, with some potential that these
storms could merge/organize later today along the instability
gradient. There is also potential that additional storm development
may occur by late afternoon/early evening across northern
Nebraska/far southern South Dakota near a surface low/troughs, with
these storms potentially increasing and evolving into an MCS
tonight, aided by a nocturnally strengthening low-level jet.

...Northern Plains...
Weak height falls amid moderate to strong instability may lead to
widely scattered thunderstorm development along a surface
trough/dryline across the Dakotas this afternoon. Moderate
westerlies should support moderate deep-layer vertical shear around
30-35 kt, sufficient for a few organized storms capable of both
large hail and damaging gusts.

...Northern New York to northern New England...
Moderate buoyancy may develop this afternoon from northern New York
into northern New England. While storm coverage remains somewhat
uncertain, deep-layer shear and relatively cool temperatures aloft
could support a couple modestly organized storms capable of locally
damaging wind, and possibly some hail.

...Mid-Atlantic vicinity...
A mid/upper-level trough and possibly an MCV will move across the
Mid Atlantic vicinity later today. Scattered thunderstorm
development is expected by afternoon from northern Virginia into
parts of Pennsylvania. While there is some uncertainty regarding the
extent of heating and destabilization, a couple stronger
cells/clusters may become capable of producing isolated damaging
winds.

..Guyer/Grams.. 07/30/2024

$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1337:3/103)

ACUS01 KWNS 311301
SWODY1
SPC AC 311259

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 AM CDT Wed Jul 31 2024

Valid 311300Z - 011200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE MISSOURI VALLEY AND UPPER MIDWEST...

...SUMMARY...
Another active severe-weather day is expected from the
northern/central Plains and Upper Midwest to the southern
Appalachians. This includes potential for large hail across parts of
the northern/central Plains, aside from a more prevalent risk of
damaging winds, some of which could be significantly strong.

...Great Plains/Mid-Missouri and Mid-Mississippi Valleys...
A relatively prominent summertime mid-level trough is readily
apparent across the northern High Plains early this morning, and
will reach the Upper Midwest tonight. Ahead of this trough,
scattered occasionally strong/locally severe convection has occurred
overnight across northern South Dakota into southern/eastern North
Dakota. This convection should further increase into midday/early
afternoon, with a more appreciable severe risk evolving across north-central/eastern South Dakota, and eventually into southwest
Minnesota by mid/late afternoon. Some initial supercells capable of
very large hail will be possible, but storm mergers within a very
unstable environment by mid/late afternoon should lead to MCS
development and heightened wind potential.

Additional potentially intense storm development is expected
southwestward near the cold front into Nebraska and Kansas, with
large hail and severe-wind gusts expected. One or more organized
clusters should regionally evolve by early/mid-evening across the
Siouxland and far eastern Nebraska into much of Iowa. Potentially
significant wind gusts in excess of 75 mph are plausible given the
steep lapse rate environment and reservoir of strong to extreme
buoyancy. Severe-MCS persistence seems viable tonight across much of Iowa/southern Minnesota, possibly northern Missouri, and Illinois.

...Central Plains/southern High Plains...
Isolated to scattered thunderstorms are expected to develop along
and ahead of the front. Deep-layer shear will be strong enough for
an isolated severe threat. Large to very large hail will be possible
with supercells in parts of central Kansas. However, the environment
will be less favorable further southwest with more of an
isolated/marginal overall severe threat expected across southwest
Kansas into northwest Oklahoma and the Texas Panhandle.

...Lower Ohio Valley/Cumberland Plateau/Southern Appalachians...
Similar to yesterday, a seasonally strong belt of northwesterly flow
aloft will persist today from the lower Ohio Valley to the southern Appalachians and coastal Southeast. Much of this will reside atop a
moist and very unstable air mass, especially across parts of the
lower Ohio Valley to Cumberland Plateau, where upwards of 3000-4000
J/kg MLCAPE may develop by peak heating outside of any MCS-related
impacts. This general scenario will likely support several organized severe-producing storms clusters/MCSs through the evening across
these regions. Somewhat higher severe probabilities (Enhanced
category) may be warranted in subsequent outlooks for parts of these
region.

For one, an MCS ongoing across central Illinois this morning may
potentially persist southeastward within this increasingly unstable environment, possibly impacting areas such as southern Indiana,
southern Ohio and parts of Kentucky/Tennessee with a heightened wind
damage potential. Aided by differential heating, scattered storms
should also increase across the southern Appalachians vicinity this
afternoon, with some organization into clusters possible given the aforementioned relative strength of winds aloft, with wind damage
possible.

...Southern Arizona...
An upper low near Baja and ongoing early day storms across parts of
northwest Mexico may influence thunderstorm development this
afternoon within a moist air mass particularly across southeast
Arizona. Some of the storms could produce severe-caliber wind gusts
and blowing dust this afternoon into early evening.

..Guyer/Grams.. 07/31/2024

$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1337:3/103)