931
ACUS48 KWNS 040902
SWOD48
SPC AC 040900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Sat May 04 2024

Valid 071200Z - 121200Z

...DISCUSSION...
An active period of organized severe thunderstorms should persist
into at least the middle of next week across parts of the southern
Plains into the mid MS Valley, Mid-South, and Midwest/OH Valley. The
15% severe areas for both Day 4/Tuesday and Day 5/Wednesday have
been expanded based on latest model trends.

...Day 4/Tuesday...
The primary upper low over the northern Plains is forecast to
gradually occlude on Tuesday. But, a strong mid-level jet streak
should overspread parts of the mid MS Valley and Midwest through the
day. A secondary surface low should develop northeastward across
these regions, with a warm front also lifting northward towards
southern WI and southern Lower MI. Thunderstorms related to
low-level warm advection and activity that has spread eastward from
the southern/central Plains may be ongoing Tuesday morning. It
remains unclear if these thunderstorms will strengthen once again as
they develop eastward in tandem with a destabilizing warm sector.
Additional robust convection will likely develop Tuesday afternoon
farther south along the dryline over the Ozarks and Mid-South. A
favorable parameter space for supercells and all severe hazards
remains evident, with the threat for severe thunderstorms continuing
Tuesday afternoon/evening across parts of the OH Valley.

...Day 5/Wednesday...
Although some differences in model guidance regarding the upper-air
pattern across the central/eastern CONUS begin to emerge by
Wednesday, there is still good agreement that a belt of strong
mid-level flow will remain in place from the southern/central Plains
northeastward to the OH Valley and Great Lakes. It appears that
another embedded shortwave trough will advance eastward from the
southern/central Plains into the mid MS Valley by Wednesday evening.
A very moist and moderately to strongly unstable airmass should
reside to the east of a cold front/dryline across these regions,
potentially extending as far north into much of the Midwest/OH
Valley. Strong deep-layer shear will favor organized convection,
including supercells and bowing line segments posing a threat for
all severe hazards. Depending on the influence of prior convection,
the very favorable parameter space forecast for Wednesday across
parts of the southern Plains into the mid MS Valley and OH Valley
may necessitate greater severe probabilities in a later outlook.

...Day 6/Thursday...
Multiple days of robust and potentially widespread convection
complicates the severe potential for Thursday. Still, some severe
risk remains evident along/south of what will probably be a
convectively reinforced front/boundary extending across parts of the
southern Plains into the Southeast and Mid-Atlantic. It is possible
that one or more 15% severe areas for Thursday will be needed for
these regions given favorable forecast instability/shear. But, this
is still dependent on better agreement in model guidance regarding
the extent/placement of moderate to strong instability, and overall
convective coverage Thursday afternoon/evening.

...Day 7/Friday and Day 8/Saturday...
The spatial extent of the warm sector should tend to become more
confined late next week and into the weekend. There is a fair amount
of spread in model guidance regarding the strength and placement of
an upper trough/low over the eastern CONUS in this time frame.
Still, a severe risk may continue Friday along/south of a front that
should be in place over parts of the Southeast. Any lingering severe
threat into Saturday may be even farther south and confined to
mainly parts of FL.

..Gleason.. 05/04/2024