####018003915####
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