SPC Apr 15, 2025 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0358 AM CDT Tue Apr 15 2025

Valid 181200Z - 231200Z

...DISCUSSION...
An active severe weather pattern expected through at least this
weekend, before predictability diminishes early next week.

...D4/Friday...
Guidance remains consistent with a broad swath of strong mid-level
southwesterlies from the southern High Plains to the Great Lakes,
downstream of a longwave trough from northern ON to the Lower CO
Valley. This will overlap a similarly oriented surface front. In
response to increasing mid-level height falls, a surface cyclone
should track across the central Great Lakes portion of the
baroclinic zone during the day. Afternoon severe may be focused in
this region with stronger low-level shear. Parts of this region may
warrant higher probabilities in later outlooks.

Farther southwest, a pronounced EML may delay the bulk of storm
development along the front until evening. But given the strong
deep-layer shear and moderate buoyancy, scattered severe storms
appear possible. 

...D5/Saturday...
Amplification of an embedded northern-stream shortwave impulse over
ON/QC should sustain an expansive swath of strong mid-level flow
from the OH Valley northeastward. The northeast extent of
appreciable instability overlapping with this regime becomes
nebulous east of the Appalachians, but scattered severe storms seem
possible from the Cumberland Plateau into the Mid-South on Saturday
afternoon to evening.

Over the southern Great Plains, lingering convection Saturday
morning renders uncertainty along the largely stalling baroclinic
zone that will undoubtedly be modified by convective outflow. But
with greater consistency in guidance handling the pivot of the basal
shortwave impulse across the Southwest, multiple rounds of strong to
severe convection are plausible through Saturday night. 

...D6/Sunday...
Predictability lessens by this period with the evolution of compact
shortwave trough ejecting onto the southern Great Plains. This
yields substantial spread in the attendant synoptic cyclone. In
addition, potentially extensive ongoing convection Sunday morning
further lessens confidence in mesoscale details. But a belt of
potentially very strong mid-level southwesterlies overlapping rich
western Gulf moisture supports inclusion of a severe-area highlight
in the South-Central States.

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