490
ACUS48 KWNS 100902
SWOD48
SPC AC 100900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Sat May 10 2025

Valid 131200Z - 181200Z

...DISCUSSION...
Medium-range guidance indicates that a generally amplified, split
mid/upper flow will persist across the mid-latitude Pacific through
North America next week.  It appears that this will include at least
a couple of significant troughs digging inland of the U.S. Pacific
Coast.  The first may already be in the process of developing
eastward across the Intermountain West early in this period
(Tuesday), before progressing across the Rockies, Great Plains and
Mississippi Valley during the middle through latter portion of next
week.  This may be followed by another significant trough digging
inland of the Pacific coast by early next weekend.

The lead trough will be relatively close on the heels of the
remnants of an initially broad quasi-stationary/cut-off low, which
may only slowly progress east of the Mississippi Valley through
Atlantic Seaboard during the early to middle portion of next week.
Low-level moisture return, in the wake of this perturbation and
ahead of the mid-level trough emerging from the West, may continue
to be impacted across at least parts of the Great Plains into mid
week.  Thereafter, there appears a general consensus that there will
be a better coupling of large-scale forcing for ascent, aided by
surface cyclogenesis, with a notable increase in low-level moisture
and destabilization across the lower Missouri Valley into the Upper
Midwest and lower Ohio Valley by late next Thursday into Thursday
night.  In the presence of strong shear, it appears that this
environment could become supportive of supercells and/or one or two
organizing severe storm clusters.

Machine learning output and other guidance suggests that potential
for strong to severe thunderstorms could persist and potentially
become more widespread across the Ohio Valley into Mid Atlantic, and
southern Great Plains, next Friday and Saturday.  However,
uncertainties remain too large at this time to introduce greater
than 15 percent severe probabilities.

..Kerr.. 05/10/2025