SPC Apr 21, 2025 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0307 AM CDT Mon Apr 21 2025

Valid 241200Z - 291200Z

...DISCUSSION...
...Day 4/Thu -- Central/Southern Plains...

Some severe thunderstorm potential is possible across the
southern/central Plains on Day 4/Thu. Similar to the Day 2-3/Tue-Wed
period, a low-amplitude, and generally modest deep-layer
southwesterly flow regime will persist. Southerly low level flow
ahead of a southward sagging front across the central Plains, and to
the east of a dryline extending southward across the southern High
Plains will sustain advection of Gulf moisture across the region. At
least some risk for isolated severe thunderstorms appears possible
within the moist/unstable warm sector. However, convection may be
ongoing across portions of the region Thursday morning, and given a
lack of any stronger upper forcing regime or surface cyclogenesis,
confidence in where greater severe potential may develop is low,
precluding 15 percent delineation at this time.

...Days 5-6/Fri-Sat -- Southern Plains vicinity...

Upper riding is forecast to overspread the Plains late in the week
ahead of a deepening western U.S. upper trough. A cold front will
sag south and east on Friday, extending from the Ohio Valley into
the southern High Plains. As the upper ridge builds, richer Gulf
moisture will develop across TX into OK. Some localized
strong/severe storms may develop across west TX during this time
within the moist upslope flow regime, but the upper ridge and weak
forcing should suppress more widespread severe potential.

...Days 7-8/Sun-Mon -- Plains to the MS Valley...

Severe potential is likely to increase from OK/TX into the central
Plains/Mid-MO Valley by early next week as the western upper trough
begins to eject eastward. This should result in stronger
southwesterly mid/upper flow overspreading a broad warm sector. This
overall pattern is a synoptically favorable spring time pattern for
severe storms across the Plains. Furthermore, control members and
ensemble members from the GFS and ECMWF are in fairly good agreement
regarding the timing/location of the ejecting upper trough and
stronger southwesterly flow overspreading the region. Nevertheless,
uncertainty remains too high to include 15 percent delineated areas
at this time. This is particularly the case of Day 7/Sun where
forecast guidance has widespread precipitation ongoing during the
morning. Given the otherwise favorable pattern, severe probabilities
will likely be needed in the coming days as details become better
refined.

Read more