RSS Mesoscale Discussions from Storm Prediction Center
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0215 AM CDT Thu Jul 09 2026
Valid 111200Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE SATURDAY
AFTERNOON AND EVENING ACROSS PARTS OF THE SOUTH CENTRAL GREAT PLAINS
THROUGH THE MID SOUTH AND TENNESSEE VALLEY...
...SUMMARY...
Strong thunderstorms with potential to produce a few damaging wind
gusts are possible in a corridor across the south central Great
Plains through Mid South and Tennessee Valley Saturday afternoon and
evening.
...Discussion...
Large-scale mid/upper ridging is forecast to continue building
across much of interior North America through this period, with the
strong core of the ridge expanding northeastward and encompassing
much of the Four Corners states through middle Missouri Valley by
late Saturday night. While one notable short wave trough is forced
inland across the British Columbia coast, increasingly split
downstream troughing is forecast to progress toward the northwestern
Atlantic, and offshore of the north Atlantic Seaboard. A lingering
mid-level shear axis, trailing to the west of the latter troughing,
may slowly continue to shift south of the Mid Atlantic and lower
Ohio/Missouri Valleys through the period.
In general, the risk for organized severe convection appears low
Saturday through Saturday night, or at least dependent on mesoscale
perturbations with low predictability at this time frame. However,
there does appear a general consensus among model output that
lower/mid-tropospheric lapse rates may remain steep enough, above a
seasonably moist boundary layer, to contribute to moderate CAPE (on
the order of 1500-2000+ J/kg) in advance of the southward advancing
shear axis. By late Saturday afternoon into Saturday evening, this
may focus strong thunderstorm development in a corridor from the
south central Great Plains into the Tennessee Valley. Some of this
activity may evolve into small clusters with potential to produce
strong to locally severe surface gusts.
..Kerr.. 07/09/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Thu Jul 09 2026
Valid 121200Z - 171200Z
...DISCUSSION...
Medium-range models continue to indicate that the center of strong
mid-level ridging building northeast of the Four Corners states will
shift across the middle Missouri Valley early next week, where it
may reach peak intensity by about Tuesday, before becoming
suppressed. Even as this commences, mid-level ridging in the
westerlies may be maintained near and north/northeast of the
international border, from the Great Plains through the Great Lakes,
while large-scale downstream troughing amplifies southeastward
across the Northeast.
Associated with this evolution, a plume of very warm elevated
mixed-layer air still appears likely to advect on the southern
fringe of a belt of strengthening flow around the northern through
northeastern periphery of this ridging. As the nose of the warmer
air overspreads the Great Lakes region early next week, forcing for
ascent associated with warm advection could begin supporting
organizing thunderstorm clusters potentially impacting portions of
New England, and/or the lower Great Lakes through Mid Atlantic.
As guidance suggests that the westerlies will initially remain split
downstream of the ridge, and a potentially notable short wave trough
(and associated cold front) migrating around its periphery and
eventually suppressing it, it remains unclear how potential frontal
and pre-frontal convection will pan out on any particular day. Due
to both synoptic and sub-synoptic predictability issues, severe
probabilities remain at less than 15 percent in the day 6-8 time
frame. However, this probably will change in later outlooks closer
to this time period, when the potential for introducing unduly large
forecast false alarm decreases.
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