RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0732 AM CDT Sat Jul 11 2026
Valid 111300Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
EASTERN OKLAHOMA INTO THE LOWER MISSISSIPPI VALLEY/TENNESSEE VALLEY
AND SOUTHEAST...AND ACROSS PARTS OF SOUTHERN ARIZONA...
...SUMMARY...
Thunderstorms capable of producing scattered severe/damaging winds
will be possible today from parts of the southern Plains eastward
into the lower Mississippi Valley and Southeast. Severe wind gusts
may also occur across portions of southern Arizona.
...Southern Plains/Ozarks into the Tennessee Valley/Southeast and
Mid-Atlantic...
Weak mid-level troughing with multiple embedded and convectively
enhanced vorticity maxima will advance slowly eastward today from
the mid MS Valley into the lower OH Valley/Midwest and TN Valley.
Ongoing thunderstorms across these regions this morning are being
aided by warm/moist advection from a modest west-southwesterly
low-level jet. Current expectations are for moderate instability to
develop by this afternoon along/south of a surface boundary that
will remain aligned generally southwest-northeast from parts of the
southern Plains into the lower MS Valley/TN Valley and Southeast.
Multiple thunderstorm clusters will likely form or persist later
today in this favorable thermodynamic regime. With modest westerly
mid-level flow present, east-southeastward propagation of
consolidated cold pools/outflow from these clusters will likely pose
a threat for scattered severe/damaging winds over a broad region as
low-level lapse rates steepen with filtered daytime heating.
The Slight Risk has been adjusted for both the influence of ongoing
morning convection and the potential for multiple clusters to spread
east-southeastward along a differential heating zone/instability
gradient across the Southeast and to the Atlantic Coast through
early evening. Isolated damaging winds may also occur farther north
along/near a weak synoptic front, but less instability is forecast
with northward extent into the OH Valley and Mid-Atlantic. Farther
west across parts of the southern Plains into the Ozarks, at least
isolated thunderstorms should develop along/south of the front this
afternoon, even though large-scale ascent will remain weaker across
these regions due to closer proximity to prominent mid-level ridging
across the Rockies. This activity will move slowly
east-southeastward while posing a threat for both severe winds and
hail, as moderate to strong instability and modest deep-layer shear
support loosely organized multicells.
...Southern Arizona...
Mid/upper-level ridging will build further over the Rockies and
Southwest today, with weak easterly mid-level flow present over
parts of AZ. Daytime heating of a seasonably moist low-level airmass
(surface dewpoints in the 50s to low 60s across southeast AZ) will
support weak to locally moderate instability as the boundary layer
becomes very deeply mixed. Thunderstorms that initially develop
across the higher terrain should spread west-southwestward into the
lower desert elevations through the afternoon/evening, with severe
wind gusts possible given ample DCAPE and inverted-v type soundings.
Isolated hail may also occur with the stronger cores.
..Gleason/Thornton.. 07/11/2026
Read more
Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Sat Jul 11 2026
Valid 141200Z - 191200Z
...DISCUSSION...
Ensemble guidance continues to indicate that the CONUS-wide
mid-level ridge centered over the north-central United States will
build westward during the upcoming week in response to a series of
mid-level troughs moving through central Canada. These troughs will
help to carve out a seasonably strong trough across eastern Canada.
By the end of the week, the US ridge will be centered over the
Rockies with the eastern Canada trough centered over Quebec. The
result will be a strong mid-level height gradient (and strong
mid-level flow) stretching from the Upper Great Lakes southeast into
the Mid-Atlantic and encompassing New England.
... Tuesday/Day 4 -- New England ...
Multiple ensemble systems continue to support a favorable severe
weather environment being in place across New England on Tuesday.
Strong diurnal heating and southwesterly surface flow should allow
surface temperatures to warm into the mid-80Fs to perhaps low-90Fs
by late afternoon ahead of a seasonably strong surface cold front.
Ahead of the cold front, surface dewpoint temperatures should rise
into the 60Fs to perhaps 70Fs, leading to MUCAPE between 1000-2000
J/kg. Current thinking is that thunderstorms will develop along and
ahead of the surface cold front during the afternoon across Quebec
and move into New England during the late afternoon before
dissipating overnight. Strong vertical shear in excess of 50 knots
will combine with strong instability to support severe
thunderstorms. The most probable scenario is for one or more broken
lines of storms to move across the region, with perhaps a few
embedded supercells. All severe hazards seem possible at this time.
... Friday/Day 7 and Beyond -- Upper Great Lakes into the
Mid-Atlantic ...
Strong northwest flow will be established between the previously
described western US ridge and eastern Canadian trough. Rich
boundary layer moisture is expected to be present to the south of a
residual cold front that will be draped somewhere from the Great
Lakes southeast into the Mid-Atlantic/Southern New England. Strong
diurnal heating each afternoon will support scattered thunderstorm
development capable of producing damaging outflows. Severe
probabilities were introduced for Day 7 with this outlook given
increasing confidence in thunderstorms developing within surface
troughing east of the Appalachians. The exact location of these
highlights will likely be refined with subsequent outlooks.
Additionally, the overall large-scale pattern seems conducive for
one or more shortwave troughs to move through the broader
northwesterly flow across this region. Given the (seasonably)
strongly unstable and sheared environment, one or more southeastward
moving MCSs may be possible during the Day 7 - Day 10 period.
Ensemble guidance varies significantly as to the timing and location
of these potential short-wave troughs, but the overall pattern would
suggest additional severe weather potential at the end of the
forecast period and in the days that follow.
Read more
