RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Sat May 16 2026
Valid 161300Z - 171200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...
...SUMMARY...
Severe thunderstorms capable of producing large to very large hail,
severe/damaging winds (some 75+ mph), and a few tornadoes should
occur this afternoon and evening across parts of the central Plains
into Iowa.
...Synopsis...
Large-scale upper troughing will gradually amplify over the western
CONUS today, while modestly enhanced west-southwesterly mid-level
flow persists over the southern/central Plains. A separate
mid/upper-level trough with strong westerly mid-level jet will move
eastward across the Great Lakes and Ontario/Quebec through the day,
while remaining generally displaced to the north of the surface warm
sector. At the surface, a weak low over the southern High Plains
this morning should reform over the central High Plains of eastern
CO by late afternoon, as large-scale ascent preceding the western
CONUS upper trough gradually overspreads this region. Greater
low-level moisture will remain confined along/south of a
convectively reinforced front from NE/IA into the southern Great
Lakes region. A dryline will extend southward from this boundary
across the southern/central High Plains.
...Central High Plains to Iowa...
High-based thunderstorms that initially develop across the higher
terrain of central CO this afternoon will eventually encounter a
more unstable airmass in eastern CO/western KS, as low-level
moisture gradually increases in the bent back region to the
north/northwest of the surface low. An increase in convective
coverage and intensity is anticipated as this activity spreads
eastward across the central High Plains late this afternoon and
evening, aided by at least moderate instability and deep-layer
shear. While some supercell potential will exist, along with a
threat for large to isolated very large hail, most guidance
continues to suggest that an intense bowing cluster will develop and
spread eastward along/near the surface boundary across southern
NE/northern KS through the evening. A greater threat for severe
winds, some of which could be significant (75+ mph), remains
apparent, as steep low/mid-level lapse rates aid in efficient
downward momentum transfer within the convective cluster. A modest
expansion has been made to the Enhanced Risk to account for the
potential of a slightly larger cluster.
A separate area of robust convective development should also occur
farther east this afternoon/evening across parts of IA and vicinity
along/near the surface front. This activity will likely be aided by
strengthening low-level warm advection this evening, and it may
persist through much of the night. The presence of steep mid-level
lapse rates, increasing low-level moisture, and daytime heating all
suggest that moderate to locally strong instability will likely be
in place by late afternoon along/south of the front. While westerly
mid-level flow should only be modestly enhanced, sufficient
deep-layer shear is forecast to support supercells initially. Large
to very large hail (isolated 2+ inches) appears possible within the
first couple hours of initiation, before thunderstorm
mergers/interactions occur and the overall mode becomes messy. Some
increase in the severe/damaging wind threat may develop if a more
organized cluster can emerge and spread east-southeastward through
the evening and early overnight hours. A few tornadoes also appear
possible through the evening with any sustained supercells. This
potential should remain focused along/near the front where backed
low-level easterly winds may locally enhance 0-1 km SRH.
...Southern High Plains...
Isolated thunderstorms may initiate this afternoon along the surface
dryline from southwest KS into the eastern OK/TX Panhandles and
western OK. While deep-layer shear will be weaker with southward
extent across the southern High Plains, a narrow zone of minimal
MLCIN along/east of the dryline may support isolated convection
capable of producing both locally severe hail and wind gusts.
...Mid Mississippi Valley into the Midwest/Ohio Valley...
Scattered to numerous thunderstorms are ongoing this morning from
central MO into the Midwest/OH Valley. This convection is likely
being aided by warm/moist advection associated with a
west-southwesterly low-level jet. While instability remains fairly
limited at the moment, some potential for occasional gusty winds and
marginally severe hail should continue through the late morning with
this activity. Greater destabilization is forecast along/south of
this ongoing convection across the lower OH Valley this afternoon.
One or more convectively enhanced MCVs may aid robust thunderstorm
development across parts of western/central KY, with a threat for
scattered damaging winds and isolated severe hail. A brief tornado
or two also appears possible. A Slight Risk has been introduced
across this area where a more focused risk for damaging winds has
become apparent in short-term guidance.
..Gleason/Bentley.. 05/16/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Sat May 16 2026
Valid 191200Z - 241200Z
...DISCUSSION...
...D4/Tuesday...
Severe potential is expected to continue D4/Tuesday as the cold
front extends from the upper Midwest to southern Plains. Moderate to
strong instability ahead of the front will continue to support
severe storms with potential for damaging wind and large hail from
the northern part of the southern Plains northeastward into the
Great Lakes Region. Probabilities were shifted eastward and
northward with this update in alignment with continued trends for
the timing/placement of the cold front.
... D5/Wednesday - D8/Saturday...
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. However,
strongest upper-level flow becomes displaced to the north from the
better instability, which will reside along and south of the front
across the southeastern US. This leads to low confidence in any
organized severe threat.
D6/Thursday through D8/Saturday, moist southerly return flow will
begin across the southern/central Plains into the weekend. Overall,
forcing for ascent will remain limited with generally weak flow and
height rises across the Plains. Areas of thunderstorms may continue
from the far southern Plains into the Southeast, but confidence in a
more focused corridor of severe weather threat remains low at this
time.
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