MD 0496 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR SOUTHERN LOWER MI...NORTHERN IN...AND NORTHWEST OH


Mesoscale Discussion 0496
NWS Storm Prediction Center Norman OK
1137 AM CDT Wed Apr 22 2026

Areas affected...far southern Lower MI...northern IN...and northwest
OH

Concerning...Severe potential...Watch unlikely 

Valid 221637Z - 221900Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm coverage will increase over the next couple
of hours, and storms will persist into early evening. The strongest
storms may produce marginally severe hail near 1 inch diameter and
locally strong gusts. A watch is not currently expected.

DISCUSSION...An isolated thunderstorm over southeast Lake Michigan
has persisted over the past hour as it slowly approaches the MI/IN
coast. During this time, MRMS MESH has estimated hail to near 1
inch. Most recently, 5 and 7 km CAPPI has decreased and echo tops
have lowered. It is unclear if this storm will continue inland. If
so, it could become reinvigorated as it moves into modestly better
low-level moisture near a surface boundary extending west to east
across far southern Lower MI/northern IN and northwest OH. 

Additional storm development is expected near/south of this surface
boundary over the next couple of hours as strong heating continues.
Steepened low-level lapse rates may support locally strong gusts
with this activity. Additionally, cool temperature aloft are
supporting modest midlevel lapse rates, fostering MUCAPE around 1000
J/kg. Strengthening northwesterly flow aloft may aid in a few better
organized cells capable of producing marginally severe hail through
early evening. Given the overall modest environment, a severe
thunderstorm watch is not currently expected.

..Leitman/Mosier.. 04/22/2026

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

ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...

LAT...LON   41868712 42048692 42258625 42318524 42308506 42238434
            41998372 41738331 41508318 40638316 40268362 40158458
            40348532 40858626 41368683 41758706 41868712 

MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

SPC 1730Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1222 PM CDT Wed Apr 22 2026

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
KANSAS INTO SOUTHERN MINNESOTA...

...SUMMARY...
Severe thunderstorms will be possible from southern Kansas into
southern Minnesota on Thursday. Large hail to very large hail,
damaging winds, and a few tornadoes are possible.

...Synopsis...

A short-wave trough initially over the northern High Plains Thursday
morning is forecast to shift east across the northern Plains into
the upper MS Valley in tandem with a belt of 50-60 kt
south-southwest winds in the mid levels. A secondary, lower-latitude
disturbance will advance into western KS and the OK/TX panhandles
late Thursday afternoon into evening, along with a more zonal
mid/upper-level jet streak. At the surface, the primary cyclone
attendant to the northern Plains system is expected to undergo
occlusion over southern into central Manitoba, while a trailing cold
front progresses east through the northern Plains into the upper MS
Valley. A pre-frontal trough or pseudo-dryline will precede the cold
front, extending from western MN through western IA and eastern NE
into central KS by early to mid afternoon. A secondary surface low
is forecast to deepen across portions of southwest KS or northwest
OK Thursday afternoon in response to the approach of the
lower-latitude disturbance mentioned above. A more classic dryline
will extend south from that low through western OK into western
north TX during the peak of the diurnal heating cycle.

...Upper MS Valley and upper Midwest through the mid/lower MO Valley
into central/eastern KS...

A broad, nocturnal, low-level wind maximum will develop across the
Great Plains tonight (Wed. night), enhancing the poleward flux of an
increasingly moist boundary layer beneath a residual EML plume
residing across the same region. The moisture increase beneath a
capping inversion at the base of the EML may result in considerable
cloud cover Thursday afternoon across portions of the warm sector
air mass. Where cloud breaks occur, model soundings indicate the
potential for MLCAPE to approach 1000-1500 J/kg across portions of
southern MN to as high as 2000-3000+ J/kg in central and eastern KS.

By early to mid afternoon, convergence along the pre-frontal
trough/dryline coupled with increasing height falls/forcing for
ascent are expected to support widely scattered thunderstorms from
portions of central and southern MN through eastern NE and western
IA, into at least northeast KS. While the strongest mid/upper-level
wind fields are expected to remain to the immediate west of the
initiating boundary, a corridor of 40-45 kt effective bulk shear
will overlie the western fringe of the warm sector, supporting
organized multicells and supercells as the initial storm mode with
an attendant threat for large to very large hail and a few
tornadoes. Subsequent upscale growth into a broken band of storms is
expected Thursday evening into Thursday night across portions of
eastern MN into western WI, western and central IA, southeast NE,
northeast KS, and northwest MO. Damaging wind potential will
increase with that mode change, with a continued risk for a few
tornadoes.

The most favorable overlap of moderate to strong instability and
vertical wind shear is expected to develop across central into
eastern KS Thursday afternoon into evening. Here, a few intense
supercells capable of all severe-weather hazards appear possible,
and a categorical upgrade to a level 3/Enhanced Risk may be required
in subsequent Day 1 outlooks.

...OK into north TX...

Moderate to strong instability (MLCAPE of 2500-3500 J/kg) is
expected to develop east of the dryline by late afternoon into early
evening on Thursday. However, strong capping at the base of the EML
casts considerable uncertainty on whether storms can develop. While
the strongest forcing for ascent associated with the secondary
short-wave trough is expected to remain across KS, subtle mid-level
height falls are forecast across northern OK. Otherwise, strong
heating to the west of the dryline and resultant deepening
circulations along it will be the primary mechanism responsible for
any storm development.

On the condition that isolated storms develop and become sustained,
the kinematic environment will support supercells capable of very
large hail and tornadoes. This is especially the case during the
evening hours as low-level shear strengthens in response to the
amplification of the low-level jet.

..Mead.. 04/22/2026

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1128 AM CDT Wed Apr 22 2026

Valid 221630Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR PARTS OF THE HIGH PLAINS/NORTHERN PLAINS...AND
ACROSS FAR SOUTHERN LOWER MICHIGAN...NORTHEAST INDIANA INTO NORTHERN
OHIO...

...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.

...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.

..Mosier/Lyons.. 04/22/2026

SPC Day 1 Fire Weather Outlook

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1049 AM CDT Wed Apr 22 2026

Valid 221700Z - 231200Z

...CRITICAL FIRE WEATHER AREA FOR EAST-CENTRAL NEW MEXICO INTO THE
NORTHERN HIGH PLAINS...
...CRITICAL FIRE WEATHER AREA FOR NORTH-CENTRAL NEBRASKA INTO
CENTRAL SOUTH DAKOTA...

...Morning Update...
No changes were made to the previous forecast. Despite good
overnight humidity recoveries across portions of the High Plains,
widespread surface RH is decreasing rapidly as temperatures rise and
deeper mixing into a dry airmass aloft ensues. Along the lee of the
Rockies into central MT, surface observations depict poor overnight
humidity recoveries have resulted in widespread 15-25 percent RH
this morning. High cloud cover east of the Divide will slowly clear
out late this morning before more spotty clouds build in this
evening. However, as the surface low strengthens across eastern MT,
strong surface winds and a deepening dry airmass aloft will continue
to support critically low RH atop very dry fuels. A 700 mb 50-70 kt
jet will develop east of the Laramie range through southwestern SD
this evening as the surface low strengthens, dragging a cold front
across the central Plains tonight. Strong west-northwesterly winds
of 20-30 mph will continue behind the front east of the Laramie
Range into the NE Panhandle with RH only increasing to 30-50
percent. These conditions will likely persist through nearly the
entire overnight period, further exacerbating the fire environment. 

See the previous discussion for more information.

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

.PREV DISCUSSION... /ISSUED 1256 AM CDT Wed Apr 22 2026/

...Synopsis...
A robust and progressive upper-level trough will move into the
Northern Rockies through today with an associated strong mid-level
jet stretching from the southern Great Basin to the Northern Plains.
An incipient lee surface low will deepen across eastern MT, while
strengthening lee troughing extends southward into the central and
southern High Plains. The broad southwest flow aloft and surface
troughing will support a expansive fire weather threat across much
of High Plains. Ascent ahead of the upper trough will aid in high
based thunderstorm development along a dry line across portions of
the Central Plains. 

...Southwest and portions of the High Plains...
A broad fire weather concern is still expected across portions of
the Southwest and High Plains corridor. The approaching mid-level
trough and related jet along with strengthening lee surface
troughing amid dry and breezy conditions will promote Critical fire
weather conditions across much of the High Plains, with a more
expansive Elevated fire weather concern into the northern High
Plains and Upper Midwest. The strongest southwest winds of 25-30 mph
will be focused across WY and southeastern MT, more coincident with
the mid-level jet max. Southwest winds of 20-25 mph along the
central and southern High Plains are expected by this afternoon
while downslope trajectories yield single digit RH values atop very
dry and still dormant fuels. Critical fire weather highlights were
maintained for this region with a locally Extremely Critical fire
weather threat, including 30+ mph winds with higher gusts, possible
in favored terrain gaps of the CO Front Range.

...North-central Nebraska into central South Dakota...
Increasing southerly winds approaching 30 mph by mid afternoon
attributed to a deepening surface trough are expected across
portions of NE Sandhills northward into central SD. Delayed boundary
layer moisture return should result in critically low RH of 10-15%
by peak afternoon heating. These conditions combined with very
receptive fuels will promote several hours of critical fire weather
conditions through the early afternoon. Initial influx of
thunderstorms could produce strong to locally severe wind gusts late
this afternoon, before improving conditions including potential for
wetting rains move into the area this evening.

...Far southwestern South Dakota, western Nebraska, far eastern
Colorado and western KS...
Isolated high based thunderstorms are possible this afternoon across
portions of the central Plains stretching southward from
southwestern SD almost to the OK Panhandle. The incoming upper
trough and associated ascent and convergence along the dry line
should allow for isolated thunderstorms to develop by early
afternoon. Deeper boundary layer moisture will reside across the
Southern Plains with precipitable water values of 0.50"-0.70" just
east of the dry line supporting only minimal precipitation as
thunderstorms propagate eastward through the evening. Isolated Dry
Thunderstorm highlights were extended farther south into far
southeastern CO and western KS based on latest forecast guidance.

...Piedmont and portions of Mid Atlantic...
West to southwest winds ahead of a cold front will affect portions
of the Mid Atlantic and Piedmont today where fuels remain critically
dry. Wind speeds of 10-15 mph along with RH falling into the 20-25%
during the afternoon will yield elevated fire weather concerns for
southern VA, much of NC and northern SC. An embedded mid-level wave
within broader northwest flow and modest 850 mb northwest winds will
enhance downslope drying in the lee of the Blue Ridge Mountains in
western NC, resulting in RH of around 15% in some areas by peak
afternoon heating.

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