775
ACUS02 KWNS 151732
SWODY2
SPC AC 151731

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1231 PM CDT Wed Jul 15 2026

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
WESTERN MONTANA...

...SUMMARY...
Severe thunderstorms will be possible across parts of western
Montana, mainly Thursday afternoon and evening. Locally damaging
winds may also occur across parts of northern New England.

...Parts of western/central MT...ID...northwest WY...eastern
OR/WA...
A seasonably strong mid/upper-level cyclone offshore of the Pacific
Northwest is forecast to move toward Vancouver Island through the
period. The glancing influence of this feature, combined with
monsoonal moisture and diurnal heating across the higher terrain,
will aid in the development of scattered thunderstorms by afternoon
across parts of ID/MT and adjacent portions of eastern OR/WA.

At this time, the greatest severe potential appears to be across
parts of western MT, where moderate buoyancy (MLCAPE of near/above
1000 J/kg) and veering wind profiles (with 30+ kt of effective shear
despite modest midlevel flow) will support development of organized
multicells and perhaps a couple of supercells, with an attendant
threat of hail and localized severe gusts. 15% hail probabilities
have been added across the area to account for this potential.

Instability is expected to be somewhat weaker across parts of ID and
eastern OR/WA, but favorable deep-layer shear may result in
development of isolated strong to severe storms. Some clustering may
eventually result in pockets of locally increased severe-wind
potential, especially where stronger pre-storm heating and
steepening of low-level lapse rates occurs.

...Parts of northern New England...
A vigorous mid/upper-level shortwave trough is forecast to move
across northern New England Thursday afternoon. Vertically
integrated smoke forecasts from the HRRR suggest that the densest
smoke will largely remain south of Maine, which would allow for
diurnal steepening of low-level lapse rates.

With limited low-level moisture, buoyancy will likely remain weak to
negligible for much of the day. However, strongly forced low-topped
convection may develop in association with the approaching shortwave
trough and attendant cold front, and move southeastward through the
afternoon. Strong flow (50+ kt at 700 mb) and steep low-level lapse
rates will support potential for strong/damaging gusts, potentially
augmented by convective downdrafts. 5% wind probabilities have been
included to account for this potential.

...Mid-Atlantic vicinity...
Similar to D1/Wednesday, storm potential is uncertain and
potentially limited Thursday across parts of the Mid-Atlantic,
despite a relatively favorable environment in the vicinity of a cold
front. Weak large-scale ascent and the potential impact of smoke on
diurnal heating/destabilization will likely limit storm coverage,
with HREF calibrated thunder probabilities currently only 10-20%.
Severe probabilities have been withheld due to uncertainty regarding
storm development/coverage, but this area will continue to be
monitored for any increasing signal of storm development within the
conditionally favorable environment.

...Arizona...
Scattered thunderstorms are again expected across parts of Arizona
on Thursday. Some storms will likely be accompanied by strong gusts,
though organized severe potential appears limited, with only very
light midlevel flow currently indicated by most guidance. Trends
will be monitored for any increase in potential for organized
clustering.

...Southwest/south-central TX...
Modestly enhanced low-level shear/SRH may persist into Thursday
morning across southwest/south-central TX. However, most guidance
suggests that convection will tend to weaken near/after 12Z. As a
result, no tornado probabilities have been introduced, though a
brief/weak tornado cannot be ruled out near the beginning of the
forecast period.

..Dean.. 07/15/2026

$$