SPC AC 260736
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0236 AM CDT Wed Jun 26 2019
Valid 281200Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
NORTH-CENTRAL MONTANA INTO WESTERN NORTH DAKOTA...
Widely scattered severe storms are expected across parts of
north-central Montana into western North Dakota on Friday. Large
hail and damaging wind gusts will be possible with these storms.
...Montana into North Dakota...
The overall pattern will not change much on Friday from the Northern
Rockies eastward into the Plains. The Pacific Northwest upper low
will lift northeastward into Alberta while a large-scale trough is
maintained across the Pacific Northwest in its wake. Strong
deep-layer southwesterly flow will continue to overspread MT into
the Canadian Prairie Provinces. Ongoing convection is expected at
the beginning of the period, likely across northwest ND. This
activity may be strong to severe initially, but will weaken as
capping associated with the Plains/Upper Midwest ridge increases
with eastward extent. Later during the afternoon and evening, storms
are expected to develop once again across parts of north-central MT
as the upper low ejects northeastward. A very moist and unstable
boundary layer beneath steep midlevel lapse rates in the midst of
strong shear will once again support large hail and damaging winds.
A cold front will shift east across MT overnight and a line of
strong to severe storms may once again move into western ND.
...Great Lakes Vicinity...
Several weak shortwave impulses, along with potential outflows
and/or MCVs related to the prior day's convection will track across
the Great Lakes vicinity on Friday. Deep layer northwesterly flow
will be somewhat modest, which may limit organized severe threat
somewhat. However, a moist and unstable boundary layer will be in
place with strong heating resulting in MLCAPE values 1500-3000 J/kg.
Depending on the timing of shortwave impulses migrating through
broad cyclonic mid/upper level flow and MCVs floating eastward
across the region, strong to severe storms will be possible, but
uncertainty is still too great to include higher than Marginal
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NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z