SPC May 15, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Fri May 15 2026

Valid 151630Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS IOWA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST AND CENTRAL/SOUTHERN PLAINS...

...SUMMARY...
Severe thunderstorms capable of producing severe/damaging winds and
large to very large hail are likely late this afternoon and evening
centered across much of Iowa. Isolated to scattered severe hail and
damaging winds are possible over a broader area from parts of the
southern High Plains to the Upper Midwest.

...Central Plains into the Upper Midwest including Iowa...
A cyclonically influenced moderately strong belt of westerlies will
exist over the northern Plains to Upper Midwest and upper Great
Lakes. The primary surface low will remain in northern Ontario, with
a trailing cold front extending southward into the Upper Midwest and
northern/central Plains. A secondary surface low will exist across
southwest Kansas and northwest Oklahoma around peak afternoon
heating, with a dryline extending south-southwestward from this low
across much of the southern High Plains.

Continued expectations are for robust thunderstorm development along
the cold front/surface trough from eastern Nebraska into Iowa to be
delayed until late afternoon or early evening (around 22-00Z), as
large-scale ascent will remain weak until a low-amplitude shortwave
trough embedded within the westerly mid-level flow eventually
overspreads the surface warm sector. Continued low-level warm/moist
advection through the day and diurnal heating will contribute to the
development of moderate to locally strong instability (2500+ J/kg
MLCAPE) across this region by early evening. While low-level winds
are forecast to remain fairly modest, enhanced mid/upper-level flow
will support sufficient (35-50 kt) deep-layer shear for updraft
organization.

Initial supercells should pose a threat for large to isolated very
large hail (2+ inches in diameter), before likely quick upscale
growth this evening across Iowa with an increasing potential for
scattered severe/damaging winds. Some of these gusts could exceed 75
mph on a localized basis given the expectation for an organized
cluster and ample instability. A tornado or two could also occur
this evening as low-level shear gradually increases with a
strengthening low-level jet.

...Southern High Plains...
While clouds linger at midday, particularly with southward extent
across west/southwest Texas, robust daytime heating will yield a
very well-mixed/deep boundary layer near/south of the secondary
surface low over southwest Kansas/northwest Oklahoma. Mid-level
temperatures will remain cool enough to support at least weak
instability, even with modest low-level moisture/surface dewpoints.
A weak mid-level shortwave trough moving from the southern Rockies
into the southern High Plains will enhance large-scale ascent late
in the day. This should support the development of high-based
thunderstorms, with occasional strong to severe wind gusts expected.
Latest short-term guidance suggests a more probable zone of
thunderstorm-related gust potential may focus across the Texas South
Plains and Low Rolling Plains. Isolated gusts of 70+ mph may occur
given the very deeply mixed boundary layer extending up to around
500 mb. Cells that develop in west/southwest Texas may also contain
some hail, with elongated hodographs in mid/upper levels.

..Guyer/Moore.. 05/15/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSYj9N

SPC May 15, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri May 15 2026

Valid 151200Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
IOWA...

...SUMMARY...
Severe storms producing damaging winds and large hail are likely
from Iowa into northeast Kansas. Isolated hail or damaging wind
gusts are possible over a large area from western Texas into
Wisconsin and western Illinois.

...Synopsis...
Moderate westerly winds aloft will exist across the northern tier of
states today, with several waves from the Pacific Northwest to the
Great Lakes. The feature of interest will move across the Dakotas
and toward the upper MS Valley late in the day, aiding storm
development and severity from NE into WI. To the south, a weak
shortwave trough will move out of NM and into TX, with mid and high
level flow enhancement along with modest cooling aloft.

At the surface, low pressure will develop from southwest KS into the
TX Panhandle, with a front extending into NE, southern MN, and into
northern WI. Increasing southerly winds during the afternoon and
evening will bring 60s F dewpoints northward toward these
boundaries, with scattered severe storms likely late in the day and
centered near Iowa.

Farther south, very steep lapse rates and a subtle upper trough
should again result in widely scattered high-based storms producing
severe gusts over the southern High Plains.

...IA into eastern NE and northeast KS...
Southerly winds and daytime heating will support moderate
instability this afternoon near a surface trough which will extend
from eastern NE into southern MN and northern WI. Dewpoints are
expected to reach into the lower 60s F, and perhaps approach 65 F
during the early evening. Meanwhile, midlevel temperatures will be
cool, resulting in steep lapse rates and robust CAPE profiles.

Storms are most likely to initiate during the late afternoon near
the IA/SD border, and extending northeastward into WI and perhaps
the central MI Upper Peninsula. Large hail will be possible with the
initial cells, supported by 60 kt deep-layer shear. Hail to 2.00"
diameter will be possible even into WI.

Farther south into IA, the deeper theta-e plume and increasing
low-level jet will enhance the severe wind risk, with an MCS
expected to develop and move east/southeast across the region.
Damaging winds with a few gusts over 70 mph are expected. Additional
clusters of severe storms are expected from southeast NE into
northeast KS as well, firmly within the low-level theta-e plume with
maximally deepened moist layer to 700 mb. Shear will not be as
strong, but the initial development is expected to be robust with
large hail and damaging wind gusts.

...Southwest KS into western Texas...
Strong heating will yield very deep mixed layers near and south of
the Panhandles surface low, while midlevel temperatures remain cool
enough to support instability despite very low dewpoints. Meanwhile,
the aforementioned shortwave trough will enhance lift late in the
day. The result will be scattered high-based thunderstorms, with
severe wind gusts expected. Isolated gusts over 70 mph may occur.
Cells that develop into southwest TX may contain marginal hail as
well, with elongated hodographs in the mid to upper levels.

..Jewell/Squitieri.. 05/15/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSY7WZ

SPC May 14, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Thu May 14 2026

Valid 142000Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN HIGH PLAINS...

...SUMMARY...
Thunderstorms with hail and severe wind gusts are possible from
Kansas/Missouri southwest into west Texas, mainly late this
afternoon and evening.

...20z Update central Plains and mid MS Valley...
Isolated convection may develop across portions of central KS late
this afternoon/evening northeast of the effective triple point.
Low-level moisture continues to rapidly advect northward across
central KS but deep mixing will likely limit the extent of the more
robust 60s F dewpoints. With moderate forecast MLCAPE (1500-2000
J/kg) amid veering wind profiles, isolated, high-based supercells
remain possible, mainly with a large hail and damaging wind risk.
Additional storms are also possible later tonight at the terminus of
a forecast 40-50 kt low-level jet across far eastern KS into MO. It
remains unclear if these storms will be robustly organized, but some
risk for hail and damaging winds may exist. Wind and hail
probabilities were expanded slightly eastward to capture this
threat.

...Southern and central High Plains...
High-based showers and a few thunderstorms have begun developing and
should gradually increase in coverage this afternoon. Weak buoyancy
(500-1000 J/kg MUCAPE) atop a very deep mixed layer is evident on 12
and 18z area RAOBs supporting the risk for damaging/severe gusts. A
few stronger high-based storms could also produce marginally severe
hail across parts of western KS where buoyancy is somewhat better.
See MCD#718 for additional short term information.

..Lyons.. 05/14/2026

.PREV DISCUSSION... /ISSUED 1121 AM CDT Thu May 14 2026/

...Central Plains including Kansas...
An upper trough over the Canadian Prairies and northern Plains will
glancingly influence the region later today, along with an embedded
disturbance or two emerging from the central Rockies early today.
Surface cyclogenesis will occur across Kansas, while a front spreads
east-southeastward across the central High Plains, and low-level
moisture steadily increases ahead of a dryline.

Initiation/sustenance of deep convection is mostly likely to
initially occur late this afternoon through around sunset across
west-central into southwest Kansas in vicinity of the surface triple
point, and to a lesser extent, along the southwestward-extending
dryline. Beneath a stout elevated mixed layer, moderate buoyancy
with 2000 J/kg MLCAPE is expected across central Kansas, which will
be coincident with a belt of 35-40 kt mid-level winds/effective
shear. Where storms do develop, forecast parameters will be quite
favorable for supercells capable of large hail and damaging winds
across much of central toward eastern Kansas. Other higher-based
severe storms are possible south-southwestward along the dryline.

...Southern High Plains including OK/TX Panhandles and West TX...
Widely scattered high-based storms should develop in vicinity of the
dryline late this afternoon/early evening. Somewhat higher
probabilities/storm coverage should exist across the Oklahoma/Texas
Panhandles and Texas South Plains. Various forecast soundings
regionally near the dryline reflect a hot and very deeply mixed
peak-heating boundary layer, to upwards of 4-4.5km AGL/500mb, with
residual CAPE and moderately strong westerlies atop the boundary
layer. Strong to potentially severe wind gusts will be possible
where storms develop in this hot/steep lapse rate environment, with
a diminishing storm intensity through the post-sunset evening hours
as the boundary layer cools.


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSY019

SPC May 14, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1121 AM CDT Thu May 14 2026

Valid 141630Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
PLAINS AND SOUTHERN HIGH PLAINS...

...SUMMARY...
Thunderstorms with hail and severe wind gusts are possible from
Kansas/Missouri southwest into west Texas, mainly late this
afternoon and evening.

...Central Plains including Kansas...
An upper trough over the Canadian Prairies and northern Plains will
glancingly influence the region later today, along with an embedded
disturbance or two emerging from the central Rockies early today.
Surface cyclogenesis will occur across Kansas, while a front spreads
east-southeastward across the central High Plains, and low-level
moisture steadily increases ahead of a dryline.

Initiation/sustenance of deep convection is mostly likely to
initially occur late this afternoon through around sunset across
west-central into southwest Kansas in vicinity of the surface triple
point, and to a lesser extent, along the southwestward-extending
dryline. Beneath a stout elevated mixed layer, moderate buoyancy
with 2000 J/kg MLCAPE is expected across central Kansas, which will
be coincident with a belt of 35-40 kt mid-level winds/effective
shear. Where storms do develop, forecast parameters will be quite
favorable for supercells capable of large hail and damaging winds
across much of central toward eastern Kansas. Other higher-based
severe storms are possible south-southwestward along the dryline.

...Southern High Plains including OK/TX Panhandles and West TX...
Widely scattered high-based storms should develop in vicinity of the
dryline late this afternoon/early evening. Somewhat higher
probabilities/storm coverage should exist across the Oklahoma/Texas
Panhandles and Texas South Plains. Various forecast soundings
regionally near the dryline reflect a hot and very deeply mixed
peak-heating boundary layer, to upwards of 4-4.5km AGL/500mb, with
residual CAPE and moderately strong westerlies atop the boundary
layer. Strong to potentially severe wind gusts will be possible
where storms develop in this hot/steep lapse rate environment, with
a diminishing storm intensity through the post-sunset evening hours
as the boundary layer cools.

..Guyer/Chalmers.. 05/14/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSXng3