SPC AC 151249
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Sat Aug 15 2026
Valid 151300Z - 161200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL HIGH PLAINS AS WELL AS THE MIDDLE OHIO VALLEY...
...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible from late afternoon into the evening across the central
High Plains. Severe wind gusts will also be possible this afternoon
into the early evening across parts of the Ohio Valley.
...Central High Plains...
Relatively moist southwesterly flow aloft coupled with strong
daytime heating and lift both from orographic effects and a weak
vorticity maximum will support another day of thunderstorms across
the central Rockies. These thunderstorms should gradually move off
the higher terrain into the central High Plains, where a moderately
buoyant airmass will be in place. Around 30 to 35 kt of effective
bulk shear is expected over the region as well, which is strong
enough to support a mixed mode with supercells and multicell line
segments. Isolated large hail is possible with any supercells, while
severe wind gusts will be possible with both supercells and line
segments. The severe threat should persist into the early to mid
evening as this complex of storms moves eastward through the central
High Plains.
...Central OH Valley...
An expansive, slow-moving MCS, characterized by widespread showers
and sub-severe thunderstorms, is centered over central IL this
morning. This MCS has been supported overnight by a southwesterly
low-level jet that extends from the southern High Plains into the
Mid MS Valley. This low-level jet is forecast to wane throughout the
morning, with a subsequent decrease in coverage and intensity of the
showers and thunderstorms within the MCS. Even so, the vorticity
maximum associated with this system will gradually drift eastward,
likely supporting renewed thunderstorm development across the
middle/upper OH Valley as it interacts with a diurnally
destabilizing airmass. Lapse rates will be poor, but dewpoints in
the 70s will still support moderate buoyancy, particularly in areas
where cloud cover does not overly inhibit diurnal heating. This
currently appears most likely from far southeast IN into southern OH
and northern KY. Strong updrafts and high precipitable water will
support the potential for wet microbursts capable of producing
damaging gusts.
...Central Appalachians into the Carolinas and GA...
A very moist airmass, characterized by dewpoints in the low to mid
70s, is in place from the GA and Carolinas into the central
Appalachians. Strong heating is forecast to destabilize this airmass
by the early afternoon, resulting in a large reservoir of moderate
buoyancy. Thunderstorm development is anticipated within this
destabilized airmass across the higher terrain of the central
Appalachians as well as any area of low-level convergence across the
remainder of the region. Vertical shear will be weak, and limited
storm organization is anticipated. Even so, the moderate buoyancy
could still support updrafts/downdrafts strong enough to produce
occasional damaging gusts.
...Central Plains/Mid MO Valley into the Mid MS Valley...
Elevated thunderstorms are expected again this evening through
tonight, initiated by both an approaching cold front and warm-air
advection. Ample low-level moisture and moderate buoyancy will be in
place, but vertical shear will be marginal. Isolated strong to
severe storms are expected, but a predominantly elevated and
clustered storm mode should limit the overall severe potential.
..Mosier/Dean.. 08/15/2026
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
SPC AC 150510
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1210 AM CDT Sat Aug 15 2026
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY TO THE SOUTHERN MID-ATLANTIC...AND ACROSS THE
CENTRAL HIGH PLAINS...
...SUMMARY...
Severe storms are possible across parts of the Ohio Valley to the
Mid-Atlantic, and in parts of the central High Plains Sunday
afternoon and evening.
...Midwest to Mid-Atlantic...
A couple of shortwave impulses/MCVs are expected to move across the
region on Sunday within broad, modestly enhanced deep-layer
west/northwesterly flow. One of these shortwave impulses may be
located over the Upper Ohio Valley Sunday morning, resulting in
ongoing cloudiness and possible convection across parts of PA/NJ and
the DelMarVa vicinity. This poses some uncertainty for severe
potential during the afternoon with northward extent across the
Mid-Atlantic. However, further south, stronger heating is
anticipated along with modest destabilization. A second shortwave
impulse/MCV will overspread the area by afternoon, supporting
additional thunderstorm develop over the upper Ohio Valley toward
the Blue Ridge. Sufficient clustering may occur as convection
organizes and spreads southeast through early evening, posing a risk
for damaging gusts.
Further north and west across the Lower Ohio Valley into the Mid-MS
Valley, a very moist and strongly unstable airmass will be in place
ahead of southeastward-advancing cold front. Vertical shear will
generally be weak, but scattered storms developing along the front
will be moving into a very unstable airmass with PW values
near/greater than 2 inches. This could support isolated to widely
scattered storms capable of wind damage.
...High Plains...
Easterly low-level flow will maintain a modestly moist boundary
layer on Sunday. Strong heating and steep midlevel lapse rates will
aid in moderate destabilization. Effective shear magnitudes around
30-40 kt will support organized cells moving east/southeast off
higher terrain by late afternoon through early evening. Large hail
and isolated strong wind gusts will be possible.
..Leitman.. 08/15/2026
WUUS02 PTSDY2
SPC AC 150631
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0131 AM CDT Sat Aug 15 2026
Valid 171200Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN/CENTRAL PLAINS...AND THE SOUTHERN APPALACHIANS...
...SUMMARY...
Strong to severe thunderstorms are possible Monday afternoon and
evening across portions of the northern and central Plains, and
parts of the southern Appalachians/Carolinas.
...Northern/Central Plains vicinity...
An upper shortwave trough will pivot eastward across central Canada
on Monday, with weak height falls forecast across parts of the
northern/central Plains into the Great Lakes during the evening.
Modest boundary layer moisture (50s to low 60s F) is forecast ahead
of a southwestward-advancing surface front. As strong heating occurs
through the afternoon and northwesterly flow aloft increases,
moderate destabilization will support widely scattered storm
development ahead of the surface front. Steep midlevel lapse rates
and around 30 kt effective shear magnitudes suggest organized
isolated cells capable of hail will be possible, in additional to
sporadic strong outflow gusts.
...Southern Appalachians/Carolinas...
A very moist airmass will be in place across the southern
Appalachians to the Mid-Atlantic coast ahead of
southeastward-advancing surface cold front on Monday. Areas of
strong heating will support moderate to strong destabilization as
thunderstorms develop ahead of the front during the afternoon.
Vertical shear is expected to remain modest, but strong instability
amid steep low-level lapse rates and PW values near 2 inches may
support isolated strong/severe microburst winds and convection
spread southeast with time through early evening.
..Leitman.. 08/15/2026
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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