102
ACUS02 KWNS 150525
SWODY2
SPC AC 150524

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 AM CDT Tue Sep 15 2026

Valid 161200Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY
MORNING ACROSS THE GREAT SALT LAKE/SALT LAKE CITY VICINITY...

...SUMMARY...
A couple of strong to severe thunderstorms appear possible across
the Greater Salt Lake City vicinity Wednesday morning.

...Discussion...
Latest model output continues to indicate that an initially digging
short wave trough along the Pacific coast will contribute to the
evolution of a notable mid/upper low near or inland of the northern
California coast by 12Z Wednesday.  Cut off from the westerlies, to
the south of a belt of broadly anticyclonic flow shifting inland of
the British Columbia coast through the Canadian Prairies, movement
thereafter likely will be slow and mostly in response to
smaller-scale perturbations pivoting around its periphery.

Downstream of the broad ridging in the westerlies, at least a couple
of notable short wave perturbations will remain progressive
within a stronger, broadly confluent regime across the eastern
Canadian Provinces through northern mid-latitude Atlantic.  It
appears that this will include one rapidly shifting  east of
northern Quebec into the Atlantic, as another digs through northern
Manitoba and northwestern Ontario.

In lower latitudes, prominent mid-level ridging may maintain
considerable influence across much of the central and southern Great
Plains into the Mid Atlantic, as its center continues a slow
west-southwestward retrogression into and across the lower
Mississippi Valley/Mid South vicinity.  There remains more
uncertainty concerning an easterly wave approaching the southern
Atlantic Seaboard and a possible mid-level perturbation suppressing
the ridging across parts of the lower Great Lakes/upper Ohio Valley
vicinity.

...Great Basin...
Beneath a difluent regime, downstream of the evolving mid-level low,
latest model output is suggestive that a focused area of large-scale
ascent may overspread the Great Salt Lake/Salt Lake City vicinity
Wednesday morning.  Based on NAM, Rapid Refresh, and RRFS forecast
soundings and other guidance, it appears that this may be
accompanied by low-level moistening supportive of modest
boundary-layer destabilization, in the  presence of strengthening
deep-layer shear becoming conducive to the evolution of supercell
structures.  This activity will pose at least some risk for severe
hail and wind.  The potential for a brief tornado remains more
uncertain.

...Ohio into lower Missouri Valleys...
A moist environment along and south of a remnant surface frontal
zone, or perhaps a preceding outflow boundary, may contribute to
the development of moderate mixed-layer CAPE with daytime heating.
This destabilization may become supportive of scattered strong
thunderstorm development during the afternoon into evening.
Although spread lingers in the model output concerning the location
and extent of this activity, this seems likely to remain focused
within a weakly sheared regime beneath this mid-level ridging.  Some
of the more vigorous cells may still pose a risk for localized
strong surface gusts, but the anticipated rather sparse coverage
continues to preclude introduction of 5 percent severe wind
probabilities at this time.

..Kerr.. 09/15/2026

$$