RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Jul 12 2026
Valid 122000Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
EASTERN GEORGIA INTO SOUTHERN NORTH CAROLINA...SOUTHERN
ARIZONA...AND PARTS OF UPPER MICHIGAN...
...SUMMARY...
Thunderstorms capable of producing isolated to scattered
severe/damaging winds may still occur this afternoon/evening across
parts of the Carolinas/Southeast into the southern Plains, and
separately over southern/central Arizona. Large hail and severe
winds also remain possible over portions of the Upper Peninsula of
Michigan.
...20Z Update...
The previous forecast (see below) remains primarily on track. The
Slight risk wind probabilities were extended southwestward into GA
to account for loosely organized bands of convection approaching a
boundary layer supportive of efficient evaporative cooling and
subsequent damaging gust potential from downbursts. Across the Upper
Great Lakes, some westward trimming of thunder/severe probabilities
was done since better forcing for ascent (e.g. WAA) is expected to
remain placed north and east over Ontario. Lastly, conditional
intensity level 1 (CIG1) was introduced across southern AZ, where
confidence is relatively higher in one of the stronger evaporatively
cooled downdrafts potentially producing a severe gust in the 75-85
mph range. Otherwise, only minor adjustments were made to thunder
and severe probabilities to reflect the latest observations and
guidance consensus.
..Squitieri.. 07/12/2026
.PREV DISCUSSION... /ISSUED 1141 AM CDT Sun Jul 12 2026/
...Carolinas/Southeast into the Southern Plains...
Midday visible-satellite imagery shows an agitated cumulus field
over north-central GA to the south of a differential heating
zone/weak front draped across the southern Appalachians and west to
east across the Carolinas. Surface temperatures will continue to
warm into the 90s F south of the more prevalent cloud cover over the
Upstate of SC and western/central NC. Scattered thunderstorms will
likely develop in several clusters across the Southeast with strong
to locally severe gusts capable of wind damage being the primary
hazard. Farther west, more widely spaced clusters will likely
develop over the central Gulf Coast states into the Ark-La-Tex
region. Locally damaging gusts will be possible with the stronger
thunderstorms.
Into parts of the southern High Plains, a seasonably moist boundary
layer will become moderately unstable by mid afternoon. Steep 0-3
km lapse rates will favor isolated severe gusts with the stronger
downdrafts. Considered a small Slight Risk over the TX South Plains
but some uncertainty regarding storm coverage precluded higher
severe probabilities this outlook update.
...Upper Midwest/Great Lakes...
Northwest-flow regime will maintain a plume of elevated mixed layer
air atop a moist low-level airmass. It is uncertain whether
additional storm development will occur this afternoon in
association with a morning cluster of strong to severe storms over
parts of the U.P. Nonetheless, sufficient shear/buoyancy for
supercells and organized storms structures lends a continued
conditional risk for severe storms into this evening/tonight. Some
guidance shows an eventual outflow-dominant cluster moving into
parts of the region tonight, with some potential for damaging gusts.
...Arizona...
Very strong heating will again yield a hot and well-mixed boundary
layer by mid afternoon. Isolated to scattered storms are forecast
to develop on the Rim and gradually propagate into the lower desert,
aided by moderate easterly mid-level flow (30-kt at 500 mb sampled
by the 12 UTC Phoenix raob). Strong evaporative cooling of the more
water-laden downdrafts will be capable of severe gusts (60-75 mph).
...Montana...
A weak front along with very strong heating may suffice for a few
high-based thunderstorms to develop late this afternoon across
north-central MT. Very steep low to mid-level lapse rates and deep
inverted-V profiles imply some potential for severe gusts with the
stronger evaporatively cooled downdrafts.
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 PM CDT Sun Jul 12 2026
Valid 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
NEW ENGLAND...
...SUMMARY...
Severe thunderstorms will be possible during the afternoon and
evening across portions of New England on Tuesday. Additional
strong-to-severe thunderstorms will be possible across parts of
western and central Montana.
...New England...
A strong shortwave trough is expected to move into the region during
the evening. The strongest forcing for ascent will likely arrive
after dark. Still, low-level moistening will promote moderate to
strong buoyancy even into the evening (1500-2500 J/kg MUCAPE). 50-60
kt of 0-6 km shear will promote organized convection capable of
large hail and severe wind gusts. A conditional tornado threat will
also exist with any supercell structures that can remain surface
based.
...Montana...
Moderate to strong mid-level cyclonic flow will continue within the
northern Rockies. An increase in low/mid-level moisture is expected
as compared to previous days. A shortwave trough coupled with at
least modest heating within the higher terrain will promote widely
scattered to scattered storms. With an increase in cloud cover
expected, it is not clear whether storms will be surface based.
Severe wind gusts and marginally severe hail are possible with the
strongest storms.
..Wendt.. 07/12/2026
Read more
