SPC Apr 17, 2025 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0330 AM CDT Thu Apr 17 2025

Valid 201200Z - 251200Z

...DISCUSSION...
...Day 4/Sun - ArkLaTex to the Mid-MS Valley...

A compact upper shortwave trough is forecast to move from the
southern High Plains to the Midwest on Sunday. While some forecast
uncertainty continues with regard to exact position of this feature,
the overall pattern suggests isolated to scattered severe
thunderstorm potential will exist across portions of east TX into
the Mid/Lower MS Valley. 

Strong southwesterly flow aloft will overspread a moist warm sector
as a surface low lifts north/northeast from OK into the Lower MO
Valley through early evening. A trailing cold front will spread east
as this occurs, while a warm front extends eastward from the Mid-MS
Valley into the OH Valley. Evolution of prior days convection is
resulting in some uncertainty regarding the western/northern extent
of severe potential. Nevertheless, a favorable environment
supporting at least isolated severe storms should extend from east
TX into parts of southern MO/IL ahead of the cold front.

...Days 5-8/Mon-Thu...

Forecast ensemble guidance from both the GEFS and EPS suggest
low-amplitude west/southwesterly flow will overspread the southern
tier of the U.S. next week. Southerly low-level flow on Day 5/Mon
across the western Gulf into the southern Plains in the wake of the
cold frontal passage on Day 4/Sun will allow for northward transport
of modified moisture. This should continue into Day 6/Tue across the
Plains. Some localized severe risk could develop across parts of the
southern Plains as an upper shortwave trough moves across the
north-central U.S. on Day 6/Tue, but poor juxtaposition between
higher quality moisture across OK/TX and stronger forcing across the
northern Plains/Upper Midwest may limit overall potential. This
low-amplitude pattern will continue through Day 8, resulting in low
predictability.

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