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Topic: SPC Apr 9, 2022 Day 4-8 Severe Weather Outlook (Read 140 times) previous topic - next topic

SPC Apr 9, 2022 Day 4-8 Severe Weather Outlook

SPC Apr 9, 2022 Day 4-8 Severe Weather Outlook

[html]Day 4-8 Outlook
     
Day 4-8 Outlook Image

Day 4-8 Convective Outlook 
NWS Storm Prediction Center Norman OK
0400 AM CDT Sat Apr 09 2022

Valid 121200Z - 171200Z

...DISCUSSION...
A substantial, multi-day severe thunderstorm event will continue on
Day 4/Tuesday and Day 5/Wednesday across much of the central CONUS.
Large to very large hail, damaging winds, and tornadoes should
occur.

...Day 4/Tuesday: Southern/Central Plains into the Mid Mississippi
Valley/Midwest...
Medium-range guidance is co*ing into somewhat better agreement
regarding the eastward progression of an upper trough across the
western/central CONUS on Day 4/Tuesday. A deep surface cyclone is
forecast to eject eastward across the central Plains through the
day, reaching the vicinity of the Upper Midwest Tuesday night.
Low-level moisture will advect rapidly northward ahead of the
surface low and east of a dryline across parts of the
southern/central Plains into the mid MS Valley. Rather steep
mid-level lapse rates are expected to be present over much of the
warm sector, which should aid in the development of moderate to
strong instability east of the dryline by Tuesday afternoon.

As mid-level height falls and related ascent preceding the upper
trough overspread the southern/central Plains, convection will
likely initiate along the dryline from eastern KS to central TX.
Even with deep-layer shear forecast to remain fairly modest through
the day, the large reservoir of buoyancy will likely support robust
severe thunderstorms. Large to very large hail should occur with
initially discrete convection, and damaging winds will be a concern
as convection grows upscale Tuesday night. Greater tornado potential
may focus across the central Plains into parts of the Midwest/mid MS
Valley, where better low-level shear should be present owing to a
strengthening low-level jet. A 30% severe area has been included
where confidence is greatest in supercells occurring Tuesday
afternoon/evening.

...Day 5/Wednesday: Southern/Central Plains into the Mississippi
Valley/Midwest and Southeast...
Convection still posing some severe threat may be ongoing Wednesday
morning across parts of the lower MS Valley and Mid-South in a
strong low-level warm advection regime. As the large-scale upper
trough ejects eastward over the central CONUS, low-level moisture
should continue to stream northward across the lower/mid MS Valley
into parts of the Midwest. There are some differences in model
guidance regarding the evolution of this upper trough on Day
5/Wednesday. Still, it appears likely that scattered to numerous
severe thunderstorms will develop across the broad warm sector and
to the east of a cold front/dryline through much of the day. Strong
deep-layer shear should co*bine with adequate instability to support
updraft organization.

All severe hazards appear possible with this convection, and any
supercells will pose a threat for tornadoes in addition to large
hail and damaging winds. Even with lingering uncertainty regarding
the possible effect of early-day convection and some model
differences in the placement of the upper trough and related surface
features, enough confidence exists to include a 30% severe area for
parts of the ArkLaTex into the lower MS Valley and Mid-South. This
region appears to have the best chance for substantial
destabilization Wednesday afternoon and discrete supercells. An
isolated severe threat will probably persist into Wednesday
evening/night across parts of the Midwest into the lower OH Valley
and Southeast. Even though low-level moisture and instability should
gradually decrease with eastward extent across these regions, both
low-level and deep-layer shear will likely remain strong. This may
support a continued severe threat through much of the overnight
hours.

...Day 6/Thursday - Day 8/Saturday...
Predictability of the synoptic-scale upper pattern across the CONUS
quickly diminishes from Day 6/Thursday onward. Depending of the
evolution of the previously discussed upper trough, and upstream
developments over the western CONUS, it appears possible that some
severe threat could linger across parts of the south-central and
southeastern states through early next weekend. However, confidence
is far too low to include any 15% severe areas at this time.


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Source: SPC Apr 9, 2022 Day 4-8 Severe Weather Outlook (http://ht**://www.spc.noaa.gov/products/exper/day4-8/)