Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1236 AM CDT Sun May 03 2026

Valid 031200Z - 041200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
NORTHERN/CENTRAL MISSOURI INTO CENTRAL ILLINOIS...

...SUMMARY...
A few strong thunderstorms are possible across parts of
northern/central Missouri and central Illinois on Sunday.

...Synopsis...
A short-wave trough with a belt of enhanced northwesterly flow
within the broader eastern US trough will overspread the Missouri
Valley through this evening. A weak cold front will extend across
portions of the central Plains into the Missouri Valley. This
boundary will be the focus for potential isolated thunderstorm
development as the short-wave moves in across the region by the
evening.

...Northern/central Missouri into central Illinois...
Moisture quality continues to be a question within the Marginal Risk
area as previously stated in prior outlooks. Surface observations
show 50s dew points have made it as far north as the Red River in
southern Oklahoma as of late Saturday evening. There remains some
question just how far north (or deep) this moisture will be by late
afternoon across Missouri/Illinois. Most 00z guidance suggests that
50 F dew points will steadily spread into Missouri through the day
today. However, afternoon sounding profiles suggest this moisture to
be thin and potentially subject to mixing. Through the afternoon,
weak convergence along the front and a mid-level capping inversion
will likely prohibit convective development. As the short-wave
ascent arrives in the evening, 00z HREF guidance suggest that at
least isolated thunderstorms may develop (as seen in ensemble paint
balls >40z dBZ and in calibrated thunder chances around 40-50%).
Temperatures aloft will be rather cold (around -20 C at 500 mb).
Even upper 40s F dewpoints will result in around 1000 to perhaps
1500 J/kg MLCAPE by late afternoon/early evening. Given steepening
lapse rate profiles and cold temperatures aloft, potential for a few
instances of severe hail and strong to severe winds will be
possible.

...Northern California/southwest Oregon...
Convection is possible during the afternoon as mid-level
temperatures cool in close proximity to the upper low off the coast.
Filtered surface heating could allow for a few stronger storms to
develop. Small hail and gusty winds are possible. Anvil-level flow
will be quite weak which will likely lead to storms that are only
strong briefly. The overall severe potential appears low.

..Thornton/Lyons.. 05/03/2026

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1203 AM CDT Sun May 03 2026

Valid 041200Z - 051200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MIDWEST...

...SUMMARY...
Strong to severe thunderstorms are possible across portions of the
Midwest late Monday afternoon into Monday night.

...Synopsis...

An upper trough will dig southward across the northern Plains/Upper
Midwest on Monday. At the same time, a upper low near CA and
attendant trough will pivot eastward toward the Southwest. At the
surface, low pressure over Ontario will develop northeast toward
James Bay while a trailing cold front moves southeast across the
northern/central Plains and the Upper Midwest/Great Lakes vicinity.
Meanwhile, a second surface low is forecast to deepen in the
vicinity of western KS/OK with a dryline extending southward across
central KS/western OK and west-central TX. Modest southerly return
flow will transport mainly 50s to near 60 F dewpoints northward
across OK/eastern KS into MO. More modest boundary layer moisture is
expected ahead of the cold front across portions of the Midwest.

...Eastern KS toward Lake Michigan and western OH...

Modest boundary layer moisture and uncertainty in timing/location of
the surface front contribute to uncertainty in severe potential for
Monday. Nevertheless, cool temperatures aloft will support steep
midlevel lapse rates and a corridor of 1000-1500 J/kg MLCAPE appears
likely ahead of the front. A lead shortwave impulse will migrate
across the OH Valley during the day. This may provide sufficient
forcing for ascent for isolated thunderstorm development within an
uncapped and modestly sheared airmass. Strong storms could produce
small hail and gusty winds. Additional strong storms are possible
during the afternoon further to the northwest near the surface front
from eastern IA toward Lake Michigan. However, boundary layer
moisture will likely be even more limited across this area, leading
to weaker instability. Nevertheless, a well mixed boundary layer
could support strong wind gusts.

Stronger ascent will arrive after 00z across the central Plains and
Mid-MS Valley vicinity in tandem with an increasing southwesterly
low-level jet. Thunderstorms are expected to develop near the triple
points in central/eastern KS and into MO as the surface cold front
drops southward. This activity may pose a risk for hail and strong
gusts.

...Southwest OK vicinity...

Some forecast guidance develops thunderstorms near the dryline late
afternoon/early evening across the southwest OK vicinity. Large
scale ascent will remain nebulous across the region and capping may
preclude thunderstorm development. However, strong heating west of
the dryline and strong convergence in model guidance are noted. If a
storm could break the cap, a severe risk could develop. However,
coverage/temporal risk would likely be limited and confidence in
this scenario is low, precluding severe probabilities at this time.

..Leitman.. 05/03/2026