RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Fri May 15 12:03:02 UTC 2026.
No Mesoscale Discussions are in effect as of Fri May 15 12:03:02 UTC 2026.
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 AM CDT Fri May 15 2026
Valid 171200Z - 181200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL PLAINS INTO THE UPPER MIDWEST...
...SUMMARY...
Severe storms will be likely Sunday from portions of the central and
southern High Plains into the Upper Midwest. Supercells capable of
all hazards will be possible before upscale growth and an emerging
damaging wind risk continues into the evening.
...Synopsis...
An upper-level trough will begin to eject across the Intermountain
West on D3/Sunday with a more subtle shortwave trough moving across
the central Plains. As a result, deepening low pressure will develop
across eastern Colorado/western Kansas with strengthening southerly
flow and warm moist advection south of a warm front lifting
northward into the northern Plains and upper Midwest. Early in the
period, elevated storms will likely be ongoing across portions of
Iowa into southern Minnesota. Scattered severe storms capable of all
hazards will be expected to develop near the warm front/low across
eastern Colorado into Nebraska and across southern South Dakota
continuing into portions of the upper-Midwest along the cold front
through the evening. A more isolated and conditional threat for
severe storms will extend southward along the dryline from western
Kansas into western Oklahoma.
...Central Plains into the Upper Midwest...
Early day elevated convection is expected to move across portions of
Iowa into the upper-Midwest. This will pose some risk for severe
hail through the morning. Across the central Plains, strong daytime
heating is expected to yield moderate to strong instability across
much of the central Plains. This in combination with strong deep
layer shear suggests a rather volatile environment, particularly
across central Nebraska into southern South Dakota/northwestern
Iowa. Guidance suggests that thunderstorms will develop across
eastern Colorado into Nebraska by the afternoon. Initial
thunderstorm development will likely be supercellular and capable of
all hazards including large to very large hail, damaging wind, and
tornadoes. As the front sags southward through the evening, eventual
upscale growth into a squall line is expected by the evening. A
strong 50 kt low-level jet will ramp up into the evening, which may
support a continuing potential for tornadoes, some of which may be
strong.
...Western Kansas into western Oklahoma...
A more conditional threat may extend southward along the dryline
into western Kansas and western Oklahoma. Guidance suggests some
signal for isolated supercells to develop along and east of the
dryline Sunday afternoon. The environment here will conditionally
favor large to very large hail, damaging wind, and perhaps a tornado
or two with the strengthening low-level jet in the evening.
..Thornton.. 05/15/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0401 AM CDT Fri May 15 2026
Valid 181200Z - 231200Z
...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/MON...
...DISCUSSION...
...Monday/Day 4...
A severe weather outbreak will be possible from Monday afternoon
into the evening and overnight period. On Monday, the western trough
will take on a negative tilt before ejecting across the central
Plains, with strong southwesterly flow aloft overspreading the
region. This will result in strong lee cyclone development across
western Kansas. A surface cold front will extend northward to a
secondary surface low across the upper Midwest. A dryline will
extend southward across portions of western Kansas into western
Oklahoma. Numerous thunderstorms are expected to develop along and
ahead of the cold front and further south along the dryline Monday
afternoon and evening from Nebraska into central Kansas. Given the
volatile air mass ahead of these features, with moderate to strong
instability and strengthening deep layer shear, initial development
will likely be supercellular. Initial supercells will pose risk of
all hazards including large to very large hail, damaging wind, and
tornadoes. As the southwesterly low-level jet increases into the
evening, large clockwise enhancement of low-level hodographs across
portions of central Kansas into northern Oklahoma may lead to an
increasing risk for strong to intense tornadoes. Additional
thunderstorm development will spread in tandem with the cold front
from the central Plains to the upper Midwest through the evening,
with potential for more widespread damaging wind and a few tornadoes
(some of which may be strong).
...Tuesday/Day 5 to Thursday/Day 7...
Severe potential is expected to continue D5/Tuesday as the cold
front extends from the upper Midwest to southern Plains. Strong to
moderate instability ahead of the front will continue to support
severe storms from the northern part of the southern Plains
northeastward into the mid Mississippi Valley. Trends are for the
front to shift eastward faster than originally expected, and as such
probabilities were shifted eastward with this update. Strong to
severe storms may extend further north into the northeast and Great
Lakes Region.
On Wednesday and Thursday, the cold front is forecast to move
southeastward across the southern Plains and mid Mississippi Valley,
extending east-northeastward into the Mid-Atlantic. A severe threat
could develop along and ahead of the front each afternoon and
evening. However, uncertainty concerning the exact location of the
front is substantial at this extended range.
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