Mesoscale Discussion 0500
NWS Storm Prediction Center Norman OK
0706 PM CDT Wed Apr 22 2026

Areas affected...northern Nebraska into much of central South Dakota

Concerning...Severe potential...Watch unlikely 

Valid 230006Z - 230300Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered storms, some possibly producing damaging gusts,
are expected to develop this evening from parts of northern Nebraska
across central South Dakota. It is uncertain whether coverage of
severe tonight will necessitate a watch.

DISCUSSION...High-based storms have recently produced several
measured severe gusts over west-central SD, though this activity is
rather disorganized. These storms are near a impressive dryline
where a warm and very dry boundary layer exists. 

Visible imagery shows substantial CU still developing along the
dryline across west-central NE, with isolated thunderstorms
developing over Cherry County. Meanwhile, surface observations
indicate dewpoints currently rising into the 40s F in that area,
with 50 or above from LBF south.

As the upper trough moves into the northern High Plains through
early tonight, height falls as well as an increasing low-level jet
to over 50 kt will likely support additional thunderstorms, mainly
from northern NE into central SD. There is some uncertainty how
severe this activity may be as the boundary layer cools and
convective inhibition increases. However, the steep lapse rate
environment combined with increasing lift and moisture may yield at
least a marginal severe wind gust threat.

..Jewell/Hart.. 04/23/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON   42080010 41970064 41860180 42120220 42740231 43950188
            45010119 45280046 45039913 44149819 42489867 42080010 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0251 PM CDT Wed Apr 22 2026

Valid 222000Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE HIGH PLAINS INTO THE NORTHERN PLAINS AND EASTERN PARTS OF THE
OHIO VALLEY...

...SUMMARY...
Isolated strong-severe thunderstorms with strong gusts and hail will
be possible across parts of the High Plains this afternoon and
evening, as well as from northeast Indiana into northern Ohio.

...20Z Update...
The previous forecast (see below) remains on track, with mainly
minor adjustments made to the general thunder and severe
probabilities to reflect the latest observations and guidance
consensus.

..Squitieri/Mosier.. 04/22/2026

.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Apr 22 2026/

...Synopsis...
Recent surface analysis shows an airmass modifying under low-level
moisture advection across the southern and central Plains, with mid
50s dewpoints reaching through central KS and into eastern
NE/western IA. This moderate low-level moisture also extends
eastward from IA into northern IL and IN, just south of a stationary
boundary that demarcates a drier, more stable airmass across much of
the Great Lakes from the modifying airmass farther south/southwest.

This analysis also reveals a pair of surface lows, one over
north-central MT and the other over far northeast WY/far southeast
MT, linked by modest surface troughing. A wavy surface trough also
extends southward to another low over southeast CO. Thunderstorm
development is anticipated today/tonight near these lows and their
related surface boundaries. In particular, strong to isolated severe
thunderstorms appear possible near the northeast WY/far southeast MT
low as it moves eastward across SD, as well as in the vicinity of
the stationary boundary across northern IN and OH.

...IN/OH...
Weak surface low over southern Lower MI has already contributed to
thunderstorm development. The airmass downstream of this low, and
south of the stationary boundary that extends east-to-west near the
MI and IN/OH border vicinity, will likely destabilize throughout the
day amid continued low-level moisture advection and strong diurnal
heating. This destabilization coupled with low-level convergence
near the low and boundary will support increasing thunderstorm
coverage. Deep-layer wind profiles will be modest, but cool
mid-level temperatures and weak-moderate buoyancy could support
isolated severe hail and gusty outflow winds with the strongest
storms.

...High Plains...
Primary surface low over central MT is forecast to deepen today as a
closed upper low currently over the Great Basin ejects northeastward
while evolving towards a more open wave. At the same time, a
secondary surface low (currently over far northeast WY/far southeast
MT) is forecast to move eastward across SD, interacting with the
modifying airmass across the northern/central Plains. Expectation is
for this airmass to be deeply mixed, with perhaps some minimal
buoyancy atop the well-mixed boundary layer. Development of a few
high-based thunderstorms is possible this afternoon/evening from NE
into SD, as well as northeast MT, along the trough where deep mixing
and inverted-v profiles will favor strong outflow gusts.

Farther south, an even more conditional risk is anticipated along a
sharpening  dryline from southwest NE and western KS into west TX.
Given the limited large-scale forcing and only weak low-level
convergence, warm mid-level temperatures and related capping
associated with a notable elevated mixed layer will likely suppress
thunderstorm development. Here, deep-layer vertical shear will be
sufficient for supercells, and a conditional risk for large hail and
strong gusts exists with any updrafts that are able to persist and
mature.  

...Western/Central NE into the Dakotas...
Additional thunderstorms are possible tonight from western/central
NE into the Dakotas as an eastward-progressing cold front interacts
with low-level moisture continuing to advect northward across the
Plains and a strengthening low-level jet. These storms will likely
be elevated behind the front, with some isolated hail possible early
in the convective cycle. Additionally, mid-level dry air will likely
remain across the region, supporting the potential for strong
outflow gusts despite the storms elevated character.

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0230 PM CDT Wed Apr 22 2026

Valid 241200Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

...SUMMARY...
A few severe thunderstorms will be possible across portions of the
Southern Plains into the Lower Mississippi Valley on Friday. Large
hail and damaging wind gusts should be the primary threats.

...Southern Plains into the Lower MS Valley...
Storms may be ongoing at the start of the period Friday morning from
parts of OK into AR/MO, and possibly into the lower OH Valley. While
a general weakening trend is expected during the morning, the
strongest early-day storms could pose a threat of isolated hail and
localized strong/damaging gusts. 

The primary severe threat is expected to develop from the afternoon
into the evening, along the primary outflow/cold front and any other
residual boundaries left over from the morning convection. The
strongest heating/destabilization is expected from parts of TX into
southeast OK, where MLCAPE of 2000-3000 may develop, with moderate
instability expected as far east as the lower MS/OH Valleys. 

At this time, the greatest diurnal storm coverage is expected from
eastern OK/northeast TX into AR, where a weak midlevel shortwave
trough and potential MCV may overlap moderate to strong buoyancy.
Effective shear will be relatively modest (generally 30-35 kt), but
sufficient to support some storm organization. Initial diurnal
development in this region could pose a threat for hail and locally
damaging wind. Low-level flow/shear will generally remain weak, but
storm/boundary interactions could also support a low tornado threat.
With time, consolidating outflows could support modest upscale
growth and a potential increase in damaging-wind potential into the
early evening as storms spread east-southeastward.  

Storm coverage may remain quite isolated across western portions of
the Level 2/Slight Risk area, due to weak large-scale ascent, but
isolated development will be possible as CINH weakens. The strongly
unstable and sufficiently sheared environment will conditionally
favor a severe threat across parts of southern OK and north TX, if
storms can be sustained.

..Dean.. 04/22/2026

Day 3-8 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0412 PM CDT Wed Apr 22 2026

Valid 241200Z - 301200Z

...Synopsis...
A large scale upper trough will persist over the central U.S. and
Canada border through Day 5/Sunday. Upper ridging across the eastern
U.S. will begin to flatten on Day 3/Friday transitioning to fairly
zonal flow through the weekend. Much of the Piedmont into the
Southeast will remain fairly dry until a low-amplitude trough enters
the southwestern U.S on Day 4/Saturday and traverses the High Plains
early next week. This pattern change could bring some relief to the
central/southern Plains into portions of the Southeast Day
5/Sunday-Day 7/Tuesday. However, in areas that do not see
appreciable rainfall, fire weather concerns are expected to linger.
Towards the end of the forecast period, an additional low-amplitude
trough is forecast to move onshore the southwestern CONUS. Given the
overall pattern, fire weather conditions should persist where fuels
remain receptive.

...Day 3-5/Friday-Sunday...
As upper troughing persists across the northern U.S., strong zonal
flow over the Southwest will promote very breezy and continued dry
conditions this weekend. With preceding days of fire weather
conditions, strong westerly downslope flow and critically low RH
atop very dry fuels will further exacerbate the fire environment,
supportive of 40% Critical probabilities across portions of the
southern Plains into the Southwest on Day 3/Friday and Day
4/Saturday.

A strong mid-level disturbance is forecast to cross over the High
Plains on Day 5/Sunday, resulting in lee cyclogenesis over portions
of western KS and northwestern OK. Behind an emerging dryline,
westerly downslope flow is expected to promote very strong winds and
critically low RH overlapping a dry fuelscape. Both 40% and 70%
Critical probabilities have been maintained over the southern Plains
and parts of West TX to encompass the expansive fire weather threat.


As the upper trough shifts east across the Midwest, a dry airmass
will persist over eastern AZ into NM early next week. While a brief
reprieve in winds is forecast for the Southwest on Day 6/Monday,
breezy conditions may return in advance of an approaching secondary
upper trough. Guidance ambiguity precludes the introduction of
probabilities at this time, however, highlights may be introduced in
future outlooks as a result of the overall upper pattern.

..Elizalde-Garcia.. 04/22/2026

...Please see www.spc.noaa.gov/fire for graphic product...