SPC Sep 20, 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
1219 AM CDT Sun Sep 20 2026

Valid 201200Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
OKLAHOMA AND FROM EASTERN COLORADO INTO FAR WESTERN KANSAS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail will be possible
this afternoon and evening across parts of Oklahoma and from eastern
Colorado into far western Kansas. Isolated severe gusts and hail
will also be possible in parts of the southern Plains, and from the
Ozarks eastward into the Ohio Valley.

...Southern Plains...
At mid-levels, southwesterly flow will be in place today over much
of the central U.S. A shortwave trough is forecast to move into
Kansas and Oklahoma this afternoon. At the surface, a low will
deepen over southwest Oklahoma today, as a cold front advances
southward into central Oklahoma. Near the front, surface dewpoints
will be in the mid to upper 60s F, which will allow moderate
instability to develop by afternoon. MLCAPE is forecast to peak in
the 2000 to 3000 J/kg range in much of central and eastern Oklahoma.
As surface temperatures warm and low-level convergence increases,
scattered thunderstorms are expected to develop in the afternoon,
with storms moving from the Low Rolling Plains and Red River Valley
northeastward into central and eastern Oklahoma.

RAP forecast soundings at 00Z near the instability axis in central
Oklahoma have MLCAPE around 3000 J/kg with 0-6 km shear near 30
knots, and 700-500 mb lapse rates in the 7 to 7.5 C/km range.
Although a mixed mode is expected, the environment will likely
support supercell development in areas that become locally
favorable. Large hail and severe wind gusts will be possible with
supercells. The potential for supercells may continue into the early
evening over east-central Oklahoma, but a gradual transition to
linear mode is expected to take place. The wind-damage threat could
become maximized in the early evening, if an organized line segment
can develop.

...Central High Plains...
A mid-level shortwave trough will move into the central High Plains
today. Ahead of this feature, a lee surface trough will deepen
during the day from northeast New Mexico into eastern Colorado.
Surface dewpoints near the surface trough will be in the 50s F,
which will enable moderate destabilization by afternoon. As surface
temperatures warm, convection will initiate in the higher terrain
during the early afternoon and move eastward into the lower
elevations. A small complex of storms will likely develop from this
convection over the central High Plains. RAP forecast soundings near
the instability axis in eastern Colorado at 00Z have MLCAPE near
1500 J/kg with 0-6 km around 40 knots, and 700-500 mb lapse rates
near 7.5 C/km. This environment should be capable of producing
supercells with large hail and severe wind gusts.

...Ozarks/Mid Mississippi and Ohio Valleys...
At mid-levels, a subtle anticyclonic flow pattern will be in place
from the Ozarks eastward into the Ohio Valley. At the surface, an
axis of moisture and instability will be located from central
Missouri eastward into southern Indiana and southern Ohio, along
which surface dewpoints will be in the 70s F. By mid to late
afternoon, MLCAPE is forecast to peak in the 2000 to 3000 J/kg range
along much of this corridor. Although large-scale ascent will remain
relatively limited, increasing low-level convergence near the moist
axis will result in isolated convective initiation. Any small
cluster that can develop and persist in the late afternoon and early
evening could produce isolated severe wind gusts.

..Broyles/Thornton.. 09/20/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVYnb3

SPC Sep 20, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Sat Sep 19 2026

Valid 200100Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTH-CENTRAL
KANSAS TO NORTHWEST MISSOURI...AND IN FAR WESTERN KANSAS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this evening across parts of the central Plains and Lower
Missouri Valley.

...Southern and Central Plains/Lower Missouri Valley...
The latest water vapor imagery shows a mid-level trough over the
Intermountain West, with southwesterly flow aloft from the southern
and central Rockies eastward into much of the Great Plains. A
shortwave trough appears to be located in central Kansas, close to
the position of a front oriented from southwest to northeast across
the central Plains. Near and to the southeast of the boundary,
surface dewpoints are in the 60s and lower 70s F, which is
contributing to moderate instability. The RAP shows an axis of
MLCAPE in the 1500 to 2500 J/kg range from central Kansas
northeastward into northwest Missouri and southern Iowa...see MCD
2312. Scattered strong to severe storms are ongoing along the
southwestern part of this corridor of moderate instability...see MCD
2311.

The 00Z sounding at Topeka has MLCAPE near 2000 J/kg with 0-6 km
shear around 20 knots, and a 0-3 km lapse rate just above 7.5 C/km.
RAP analysis suggests that deep-layer shear is stronger near the
front. The environment will support a continued severe threat this
evening. Severe wind gusts and isolated large hail will be the
primary threats. The line that is currently developing in northeast
Kansas may continue to have a severe threat later this evening as it
tracks northeastward into northwest Missouri and far southern Iowa.
A marginal wind-damage threat will extend southwestward along a
surface trough into parts of west Texas.

In the central High Plains, the western edge of moderate instability
extends westward into far western Kansas. Scattered strong storms
are ongoing near the Colorado-Kansas state line where the RAP has
MLCAPE around 1500 J/kg. The Goodland WSR-88D VWP has 0-6 km shear
around 50 knots, and the RAP has 700-500 mb lapse rates in western
Kansas near 7.5 C/km. This will support a supercell threat this
evening with a potential for isolated large hail. Severe wind gusts
will also be possible...see MCD 2313.

..Broyles.. 09/20/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVYhMD

SPC Sep 19, 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 Sat Sep 19 2026

Valid 191630Z - 201200Z

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

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this afternoon and evening across parts of the central
Plains.

...Ohio Valley...
Recent surface analysis places a weak low over northern IN, along
the northern end of an outflow boundary that is pushing
southward/south-southeastward across central IL and central IN.
Airmass south of this boundary is very moist, with dewpoints
generally in the upper 60s to low 70s. Filtered heating is
anticipated across this region today, with the resulting warm and
moist conditions supporting moderate buoyancy. The strongest
buoyancy is expected from southern IN into southwest OH and adjacent
far northern KY. The surging character of the outflow combined with
limited deep-layer vertical shear results in uncertainty regarding
how thunderstorms will evolve this afternoon, with at least some
potential for a predominance of undercut, poorly organized updrafts.
That being said, potential also exists for just enough
buoyancy/shear balance for a few stronger, more persistent bowing
clusters. Steep low-level lapse rates will promote strong to severe
gusts with any more persistent line segments that develop.

...Southern Appalachians/Southeast...
Warm and moist conditions will support airmass destabilization and
the potential of afternoon/evening thunderstorms across the region.
The region is largely void of coherent surface features, so any
convective initiation would likely be tied to mesoscale areas of
low-level confluence. Widely scattered to scattered storms are
forecast during the afternoon, and a few stronger water-loaded
downdrafts capable of 50 to 60 mph gusts are possible.

...Central and Southern Plains/Lower Missouri Valley...
Recent surface analysis places a low over southwest IA, with a cold
front extending back southwestward through southwest KS and the
central OK Panhandle into the northwest TX Panhandle. This front is
expected to slowly push south while larger-scale mid-level troughing
over the Great Basin and central Rockies gradually shifts eastward.
A seasonably moist airmass is in place ahead of the cold front, and
moderate buoyancy is expected as this airmass heats and destabilizes
this afternoon.

Low-level convergence along the cold front, augmented by modest
large-scale forcing for ascent, will support scattered storm
development during the late afternoon and early evening as
convective inhibition is locally eroded. Given adequate speed and
directional shear, a few short-lived supercells are possible early
in the convective cycle, particularly across KS. Large hail will be
possible with the stronger updrafts. Thereafter, high-based storm
character coupled with steep low-level lapse rates will support
strong to severe gusts, including the potential for a few gusts of
60 to 75 mph.

...Central High Plains...
Low-level easterly flow across the central High Plains will help
maintain at least upper 50s/low 60s dewpoints across the region this
afternoon/evening. The low-amplitude shortwave trough currently
moving through northern NV/UT is forecast to continue eastward,
interacting with this moist and unstable airmass to support
scattered thunderstorm development. With time, strengthening
mid-level flow will help support upscale growth from a loosely
organized band of a storms (including some supercells) to a more
organized linear cluster. Some hail is possible early with the more
cellular development, with wind gusts becoming more likely with
time. There is some indication this activity may continue into
western KS during the late evening and early overnight.

..Mosier/Chalmers.. 09/19/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVYbJk

SPC Sep 19, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0725 AM CDT Sat Sep 19 2026

Valid 191300Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this afternoon and evening across parts of the central
Plains.

...Central and Southern Plains/Lower Missouri Valley...
Larger-scale mid-level troughing over the Great Basin and central
Rockies will gradually shift eastward with falling heights spreading
east across the central Great Plains and lower MO Valley through
daybreak Sunday. A cold front draped in a general west-southwest to
east-northeast orientation from central High Plains to the mid MS
Valley will slowly push south. A seasonably moist airmass ahead of
the boundary over KS/MO into northwestern OK will become moderately
unstable by mid afternoon. Scattered storm development is
eventually expected during the late afternoon and early evening as
convective inhibition is locally eroded. Steep 0-3 km lapse rates
(8.5-9.5 deg C/km) will aid in storm vigor and the potential for
strong evaporative cooling with the more intense cores. Have
introduced an intensity level 1 for the wind hazard (60-75 mph
gusts) where a combination of HREF ensemble guidance and higher PW
and lapse rates overlap. A few short-lived supercells are possible
given the adequate speed and directional shear according to model
forecast soundings across the KS vicinity. Large hail will be
possible with the stronger updrafts. This threat will likely
diminish during the evening.

...Central High Plains...
The airmass north of a cool front will heat/destabilize through
mid-late afternoon ahead of the aforementioned upper-level trough
impinging on the region from the west. Some easterly component to
the low-level flow will aid in maintaining a fetch of sufficient
moisture (mainly 50s deg F surface dewpoints) into much of the
central High Plains. Models indicate scattered storms developing
near/east of I-25 with increasing storm coverage expected through
the early evening. With time, a loosely organized band of a storms
(including some supercells) will probably grow upscale and
transition to a linear cluster as it moves east across eastern CO
into western KS. Have included 15-percent wind probabilities across
eastern CO to account for this favorable storm mode evolution for
severe gusts. There is some indication this activity may continue
into western KS during the late evening and early overnight,
prompting the inclusion of low severe-wind probabilities.
Uncertainty remains regarding the character/intensity of this
activity across western KS (e.g., 19/06z MPAS-HT), especially if the
depth of post-frontal airmass and near-surface static stability are
similar to the 19/06z NAM depiction.

...Ohio Valley/Southern Appalachians/Southeast...
West-northwesterly mid-level flow will be located over much of the
northeastern third of the U.S. today. At the surface, an axis of
low-level moisture will be oriented from the Ohio Valley southward
into the southern Appalachians, along which moderate instability is
expected to be in place by afternoon. Widely scattered to scattered
storms are forecast during the afternoon. A few of the stronger
downdrafts may be capable of a strong to locally severe wind-gust
threat (50 to 60 mph) capable of wind damage.

..Smith/Mead.. 09/19/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVYQ4S