SPC May 5, 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
1236 AM CDT Tue May 05 2026

Valid 051200Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTERED OVER
ARKANSAS AND EXTENDING FROM NORTHEAST TEXAS INTO WESTERN
TENNESSEE...

...SUMMARY...
Widely scattered severe storms are possible Tuesday afternoon into
Tuesday night from northeast Texas into western Tennessee, with the
main threat centered over Arkansas. The strongest storms will be
capable of large hail, damaging winds, and a few tornadoes. More
isolated, strong to severe storms are possible across parts of the
Northeast.

...Synopsis...

A vigorous, mid-level low over Ontario this evening is forecast to
evolve into an open wave while translating east into Quebec on
Tuesday. An accompanying belt of strong, mid/upper-level winds will
overspread the lower Great Lakes and northern New England in tandem
with modest height falls related to a vorticity maximum pivoting
through the base of the parent system. Elsewhere, a mid-level low
currently along the CA coast is expected to weaken while shifting
through the lower-CO Valley to the vicinity of the Four Corners
region. A belt of 50-70 kt winds at 500 mb are forecast downstream
from that feature, extending from the southern Plains into the Mid
South on Tuesday afternoon into evening.

In the low levels, a cold front is expected to extend from southeast
Quebec through the OH and mid-MS Valleys to low pressure over OK
Tuesday morning. The northern extension of the boundary will move
into the lower Great Lakes and northern New England during the peak
of the diurnal heating cycle. The segment of the front across the
Ozarks and Ozark Plateau may be temporarily displaced to the south
Tuesday morning due to overnight thunderstorm activity. However by
afternoon, the front is expected to refocus in the vicinity of the
MO-AR border, ahead of a weakening surface low moving through
eastern OK into western AR. The western extension of the cold front
trailing the surface low is expected to advance southeast through
the Red River Valley.

...Northeast Texas into the southern Missouri and western
Tennessee...

As mentioned in the synopsis, a complex of thunderstorms may be
ongoing at the start of the forecast period across portions of MO
into northern AR. That activity is expected to shift east of the
area by late morning or early afternoon, with some lingering shower
and thunderstorm development occurring to the north of the front in
central MO. In the wake of the early-day convection, HREF cloud
forecasts indicate the potential for considerable high-level clouds
and pockets of thicker low-cloudiness, which could limit the
potential for stronger diabatic warming within the pre-frontal air
mass. Nonetheless, the presence of boundary-layer dewpoints in the
60s in conjunction with an elevated-mixed layer (EML) plume will
support a moderately unstable air mass by afternoon with MLCAPE of
1000-2000 J/kg.

Neutral to slight height rises are forecast in the mid levels during
the peak of the diurnal heating cycle with model forecast soundings
indicating considerable capping at the base of the EML. As such,
eventual storm coverage remains uncertain. The 00z high-resolution
models suggest that isolated to widely scattered thunderstorms will
become increasingly likely by late afternoon or early evening along
the frontal segment along the MO-AR border, immediately
east/northeast of the surface low. Additional, isolated storm
development also appears possible from the vicinity of the surface
low southwest along the cold front into northeast TX, mainly during
the evening hours.

The favorable overlap of moderate instability and strong deep-layer
shear will favor supercell storm modes, especially given the
anticipated weak forcing for ascent. Large hail will be the
predominant severe-weather hazard initially. A few tornadoes appear
possible across portions of northern AR, potentially into western TN
from late afternoon through the evening association with any
sustained supercells. Here, the presence of a 35-40 kt low-level jet
will yield effective SRH of 200-300 m2/s2 amidst a moist/low-LCL
environment. Storms may eventually grow upscale into clusters, at
which point damaging winds would become a growing concern.

...Lower Great Lakes into northern New England...

Moisture advection occurring along a southwesterly low-level jet
will allow dewpoints to rise into the 50s within the pre-frontal
warm sector on Tuesday. And while mid-level lapse rates are not
expected to be particularly steep, the moisture increase combined
with daytime heating and the resultant steepening of low-level lapse
rates will result in MLCAPE of 500 to perhaps 1000 J/kg. Increasing
height falls aloft and convergence/lift along the cold front are
expected to support surface-based storm development by early
afternoon within the destabilizing air mass across portions of
upstate NY. The storms will quickly overspread northern portions of
VT, NH, and ME during the afternoon into early evening.

The 00z high-resolution models indicate the potential for transient
supercell and bowing structures, which appears reasonable given the
presence of a relatively strong, deep-layer wind field. In that
scenario, isolated occurrences of damaging winds and perhaps some
marginally severe hail appear possible. The tornado threat will be
conditional on sufficient instability to support more sustained
supercell structures. A level 1/Marginal Risk will be maintained;
however, if it becomes apparent that stronger instability will
develop than is currently anticipated, an upgraded to level 2/Slight
Risk may become necessary.

..Mead/Lyons.. 05/05/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSN9dq

SPC May 5, 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
0752 PM CDT Mon May 04 2026

Valid 050100Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN
KANSAS INTO NORTHERN INDIANA AND NORTHWEST OHIO...

...SUMMARY...
Widely scattered severe thunderstorms capable of large hail and
damaging wind gusts are possible from eastern Kansas into the
portions of the Ohio Valley this evening into tonight. A
conditional threat for severe storms with large to very large hail
extends into portions of southern Plains through the remainder of
the evening.

...Mid-Mississippi and Ohio Valleys....

Widely scattered, strong to severe storms are ongoing this evening
along and ahead of a progressive cold front from southern lower MI
into northern IL and far southeast IA with visible satellite
indicating additional storm attempts into portions of northern MO. A
separate area of thunderstorms is ongoing within the open warm
sector east of St. Louis where hail up two inches in diameter has
been reported. In the absence of more substantial boundary-layer
moisture content, 00z observed soundings revealed the presence of
steep low/mid-level lapse rates are largely contributing to MLCAPE
of around 1000 J/kg. Meanwhile, the accompanying kinematic
environment features a vertically veering wind profile with around
40 kt of effective bulk shear magnitudes and modestly strong
low-level shear (effective SRH of 150-200 m2/s2).

Current thinking is that ongoing storms will remain capable of
isolated occurrences of large hail and locally damaging wind gusts
for the next few hours as increasing moisture content along a
nocturnal low-level jet offsets cooling in the boundary layer. The
threat should tend to diminish overnight as the boundary layer
gradually stabilizes.

For additional information on near-term details, see MCDs 640 and
641.

...Eastern Kansas into western Missouri...

Isolated to widely scattered thunderstorms have persisted this
evening across portions of western into central KS, aided by a weak
mid-level impulse moving through the central High Plains. A number
of high-resolution models suggest that activity will intensify later
this evening into tonight as it drifts east of the I-35 corridor and
encounters an increasingly unstable air mass in place across eastern
KS into western MO. A strengthening low-level jet will enhance
moisture transport into the growing complex of storms with large
hail being the primary hazard initially. With time, the models
suggest upscale growth into one or more forward-propagating clusters
with an increased risk for damaging wind gusts.

..Mead.. 05/05/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSMzMT

SPC May 4, 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
1130 AM CDT Mon May 04 2026

Valid 041630Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
MISSOURI VALLEY INTO THE SOUTHERN GREAT LAKES...

...SUMMARY...
Scattered severe thunderstorms capable of large hail and damaging
wind gusts are possible across portions of the Midwest this
afternoon into tonight. A conditional threat for severe storms with
large to very large hail extends into portions of the
central/southern Plains.

...IL into the southern Great Lakes...
A mid-level vorticity maximum over the lower MO Valley is forecast
to move east across IL through the late afternoon and into IN-OH
tonight. An associated speed maximum at 700 mb will intensify and
overspread IL (40-50 kt) east into the southern Great Lakes while a
pronounced strengthening of 850-mb flow (50 kt) occurs during the
21-03z period. Cold mid-level temperatures (-18 deg C at 500 mb)
will act to offset initially meager moisture. Model guidance varies
considerably regarding moisture quality with ample spread amongst
different model cores/PBL schemes. However, it seems a narrow
corridor of lower to mid 50s surface dewpoints will extend
east-northeast from the lower MO Valley into the southern Great
Lakes by mid to late afternoon. Forecast soundings show weak to
moderate buoyancy (500-1250 J/kg MLCAPE). Morning model guidance
shows widely scattered to scattered storms developing within the
warm conveyor during peak heating as convective inhibition erodes.
Have expanded the Slight Risk farther east into this region to
account for a hail/wind risk with the stronger storms. Uncertainty
remains regarding quality of boundary-layer moisture across the
northern third of IN into northwest OH where hodographs become
enlarged later this afternoon into the early evening. Will
re-evaluate the tornado risk for the 20 UTC outlook if in fact
moisture quality seems sufficient for a focused, short-duration
tornado risk across the aforementioned corridor.

...Eastern KS into the Mid MS Valley...
Thunderstorm development is anticipated during the afternoon along a
cold forecast to extend through southern WI and
eastern/southern IA. Thunderstorms along the front will initially be
displaced north of the better shear and buoyancy, so somewhat
transient updraft structures and/or frontal undercutting will likely
limit storm severity. Even so, high cloud bases and a deeply mixed
boundary layer could result in a few strong gusts. Later in the
evening, more storm development appears likely on the front as it
moves into eastern KS and northern/central MO. Here, stronger shear
and buoyancy should support more robust updrafts and a relatively
higher probability for severe storms. Large to very large hail is
the primary risk.

...Central Kansas into Oklahoma and northern Texas...
A dryline will extend from central KS south-southwestward into
northwest TX by mid afternoon as a surface low evolves near the TX
Panhandle/OK/KS border region. Strong diurnal heating will likely
erode most convective inhibition by the early evening, while steep
lapse rates contribute to moderate buoyancy along the dryline.
Isolated thunderstorms are possible on the dryline from central KS
into northwest TX during the 22-02 UTC period. Veering and
strengthening flow with height beneath 100-kt westerly 200-mb flow
will support supercells. Isolated large to very large hail will be
the primary risk with the stronger storms, although severe gusts are
also possible.

..Smith/Chalmers.. 05/04/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSMqB6

SPC May 4, 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
0752 AM CDT Mon May 04 2026

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
KANSAS ACROSS NORTHERN/CENTRAL MISSOURI INTO WEST-CENTRAL
ILLINOIS...

...SUMMARY...
Strong to severe thunderstorms capable of large hail and damaging
wind are possible across portions of the Midwest this afternoon into
tonight. A conditional threat for severe storms with large to very
large hail extends into portions of the central/southern Plains.

...Synopsis...
Early-morning satellite imagery shows a large upper low off the
central CA coast, with an extensive fetch of southwesterly flow
aloft from the base of this low through northern Mexico and the
Southwest States into the southern High Plains. A deep cyclone
exists over central Canada as well. Between these two primary
features, a low-amplitude shortwave trough is currently moving
southeastward across NE.

Several shortwave troughs are forecast to rotate around the Canadian
cyclone, contributing to some deepening and eastward progression. An
associated surface low, currently over northwestern Ontario, will
move eastward as well. The deepening of the upper trough across the
northern Plains and progression of the surface low will force a cold
front southward/southeastward across the Upper Midwest and Middle MO
Valley by this evening, and through the central Plains, and Lower MO
and Mid MS Valleys by early tomorrow. Increasing low-level moisture
is anticipated ahead of this cold front, supporting the potential
for thunderstorms as this front interacts with this moisture and
associated buoyancy.

...Eastern KS into Mid MS Valley and Lower MI...
Thunderstorm development is anticipated during the afternoon, both
along the front, which should extend through southern WI and
eastern/southern IA, and within the warm-air advection regime ahead
of the front. Thunderstorms along the front will initially be
displaced north of the better shear and buoyancy, so somewhat
transient updraft structures and/or frontal undercutting will likely
limit storm severity. Even so, high cloud bases and a deeply mixed
boundary layer could result in a few strong gusts. Later in the
evening, more storm development appears likely on the front as it
moves into eastern KS and northern/central MO. Here, stronger shear
and buoyancy should support more robust updrafts and a relatively
higher probability for severe storms. Large hail is the primary
risk.

Any thunderstorms that develop within the warm-air advection regime
ahead of the front during the afternoon and early evening should
interact with greater buoyancy (particularly from northeast IL,
northern IL and southern Lower MI where less boundary-layer mixing
could result in slightly higher dewpoints) and moderate vertical
shear. A few stronger, more organized storms are possible in this
area, although weaker upper flow could limit discreteness and result
in a trend towards a more clustered storm mode.

...Central Kansas into Oklahoma and northern Texas...
A sharp dryline is expected to develop from central KS
south-southwestward into northwest TX. Given the veering surface
winds, convergence along the dryline will likely be modest
throughout much of the afternoon. However, some backing is possible
during the evening as a surface low moves eastward across southwest
KS towards northwest OK. Strong diurnal heating will likely erode
most convective inhibition by the early evening, while steep lapse
rates contribute to moderate buoyancy. These factors could be enough
to force isolated initiation on the dryline from central KS into
northwest TX. Upper-level flow will be strengthening across the
region throughout the period, and any storms that do form will have
ample deep-layer shear to support supercells. Large to very large
hail would be the primary risk early in the convective cycle, with
dry mid-levels also supporting strong downdrafts as storms begin to
weaken and collapse.

..Mosier/Dean.. 05/04/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TSMWY3