865
ACUS48 KWNS 190848
SWOD48
SPC AC 190847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Sat Jul 19 2025

Valid 221200Z - 271200Z

...DISCUSSION...
Medium-range guidance continues to indicate a belt of strengthening
west-northwesterly flow across Ontario, Quebec and adjacent portions
of the U.S. Upper Midwest/Great Lakes toward the St. Lawrence Valley
and Northeast during the middle to latter portions of the coming
work week.  This is forecast to occur as a notable mid-level low,
digging southeast of the Canadian Arctic latitudes over the next
couple of days, accelerates east-southeast of the Canadian Northwest
Territories through the Hudson Bay vicinity and northern Quebec, to
the north of an increasingly prominent high becoming centered over
the Ohio/Tennessee Valleys by next Wednesday/Thursday.

Potential forcing for ascent associated with smaller-scale
perturbations emerging from initial troughing across the Pacific
Northwest, or other more subtle perturbations migrating around the
northwestern periphery of the high, before progressing eastward
along the southern periphery of this regime remain much more
unclear.  However, guidance remains suggestive that moistening
beneath a plume of eastward advecting elevated mixed-layer air might
become supportive of destabilization conducive to the evolution of
progressive organized clusters of storms capable of producing swaths
of strong to severe gusts, in the presence of favorable shear.

..Kerr.. 07/19/2025