SPC Mar 31, 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
0736 AM CDT Tue Mar 31 2026

Valid 311300Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE MID
MISSISSIPPI VALLEY ACROSS THE OHIO VALLEY AND SOUTHERN GREAT
LAKES...AND ACROSS WESTERN OKLAHOMA AND FAR NORTHWEST TEXAS...

...SUMMARY...
Scattered severe thunderstorms with damaging wind gusts and large
hail are expected today from the Mid Mississippi Valley across the
Ohio Valley and southern Great Lakes. Isolated severe storms capable
of large hail and damaging gusts are possible across western
Oklahoma and far northwest Texas as well.

...Synopsis...
Upper pattern is forecast to trend away from its previously more
zonal configuration towards more amplification today as the general
pattern begins to become more active. Several shortwave troughs are
expected across the CONUS today, combining with an expansive warm
sector to support an extensive stretch of strong to severe
thunderstorms from the southern High Plains into the Northeast.
Thunderstorms are also possible within the moist and confluent flow
from the Gulf Coast into the southern Appalachians and the
anonymously moist airmass across the Southwest. Additionally,
thunderstorms are possible during the second half of the period from
northern CA through the Great Basin as shortwave trough moves
quickly eastward across the region overnight.

...Mid/Upper MS Valley across the southern Great Lakes and OH Valley
into the Northeast...
Recent surface analysis places a low near the IA/WI border vicinity,
with perhaps another weak low farther southwest across southwest IA.
A warm front extends eastward from the IA/WI border surface low
across southern WI and southern Lower MI. Showers and thunderstorms
occurred overnight along and north of this boundary, with the
primary remnants currently over southwestern ON towards western NY.
Additional thunderstorm development is beginning to the northwest of
the IA/WI border surface low as well as farther south within the
warm sector across northern IL. This activity is likely supported by
a combination of persistent warm-air advection and ascent linked to
a subtle shortwave trough moving through IA. Most guidance suggests
this activity, particularly the IL cluster, increases in coverage
and intensity over the next several hours as it continues eastward
across Lower MI and eventually into western PA/western NY. Some
intensification of the convective remnants moving across southwest
ON is possible as well. Robust deep-layer westerly flow amid at
least modest buoyancy will support damaging gusts as the primary
severe risk with these clusters. There is also enough low-level
curvature to support a low-probability tornado risk, particularly
along the southwest flanks of the IL and ON clusters where a more
cell-in-line convective mode is possible. A line-embedded
circulation could also occur if these clusters can become more
organized.

How these clusters evolve, in particular the strength of any
outflow, will dictate the extent of airmass recovery in their wake.
This is particularly true across the OH Valley where much of the
guidance suggests another round of thunderstorms is possible along a
cold front forecast to move across the region this evening. Current
expectation is that the airmass will support strong to severe
thunderstorms, especially from central IN into central IL where the
influence of antecedent convection should be minimal. Steep lapse
rates and moderate shear will support a hail risk with the initially
more cellular development along the front. A trend towards a more
linear mode is anticipated thereafter, with undercutting by the cold
front likely as well.

Lastly, elevated thunderstorms are expected overnight from northern
MO into southern IA and central IL amid steep lapse rates and a
strengthening low-level jet. Marginally severe hail is possible with
this activity as well.

...Central/Southern Plains...
Recent surface analysis places a low over southwest KS, with a
dryline extending southwestward from this low through southeast NM
into Far West TX. This low is forecast to shift southeastward along
the leading edge of a cold front pushing southward into the TX
Panhandle and western OK, with its associated dryline gradually
shifting eastward. Increasing low-level moisture and strong heating
will help destabilize the airmass ahead of the front and surface
low. Low-level convergence along the front/dryline, and particularly
near the surface low, will support convective initiation. Vertical
shear will be sufficient for storm organization and a few supercells
are possible. Steep lapse rates and strong shear in the
cloud-bearing layer suggest large hail is possible early in the
convective cycle, while high LCLs suggest a trend toward strong
downbursts thereafter.

..Mosier/Bentley.. 03/31/2026


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SPC Mar 31, 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
1259 AM CDT Tue Mar 31 2026

Valid 311200Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST EASTWARD INTO THE CENTRAL APPALACHIANS...

...SUMMARY...
Scattered severe thunderstorms with damaging wind gusts and isolated
large hail are expected today into this evening across parts of the
Great Lakes and Midwest. Isolated severe storms may also occur from
the mid to upper Mississippi Valley southwestward into the southern
and central Plains.

...Upper Midwest/Southern Great Lakes/Mid to Upper Mississippi
Valley...
An upper-level trough will move eastward into the Great Lakes today,
as a more subtle shortwave trough moves through the Midwest. At the
surface, a low will move into Lower Michigan as a trailing cold
front advances southeastward across the mid to upper Mississippi
Valley. Ahead of the front, a cluster of storms is expected to move
eastward through southern Wisconsin and northern Illinois during the
morning, reaching Lower Michigan by midday. To the south of this
cluster of storms, surface heating with dewpoints of 55 to 60 F will
contribute to a broad area of instability. An outflow boundary
appears likely to move into northern Indiana and northern Ohio
around midday, where scattered convective initiation should take
place in the early afternoon. These storms are forecast to move
eastward into the central Appalachians during the mid to late
afternoon, with additional storms forming further west across
northern Missouri and central Illinois. As cells gradually increase
in coverage during the late afternoon and early evening, MCS
development will be possible.

The greatest chance for severe storms appears likely to occur this
afternoon and evening from far northeast Illinois eastward into
western New York and northern Pennsylvania. Along much of this
east-to-west corridor, MLCAPE is forecast to increase into the 1000
to 1500 J/kg range by late afternoon. Deep-layer shear will also
increase across the Midwest as a 75 to 90 knot mid-level jet moves
into the Great Lakes. Along the southern periphery of the jet, lift
and shear will be sufficiently strong for organized storms.
Supercells and short multicell line segments, associated with severe
wind gusts and large hail, are expected from mid afternoon into the
evening. Increasing cell coverage could result in a somewhat larger
severe line segment, with damaging wind gusts as the primary threat.

Further west into the lower Missouri Valley, isolated severe storms
are expected to develop in the late afternoon and early evening.
This area will be located further from the mid-level jet, which will
make deep-layer shear and low-level flow a bit weaker. For this
reason, the severe threat is expected to remain more localized.

...Southern and Central Plains...
Southwesterly mid-level flow will remain in place over the southern
and central Plains today. At the surface, a cold front will advance
southward across the Texas Panhandle extending northeastward into
southern and eastern Kansas. Ahead of the front, surface dewpoints
in the 55 to 60 F range will contribute to the development of
moderate instability by afternoon, with MLCAPE rising into the 1500
to 2000 J/kg range. As low-level convergence increases along and to
the south of the front, isolated to scattered thunderstorms will
form. RAP forecast soundings near the instability axis late this
afternoon have large surface temperature-dewpoint depressions with
very steep low to mid-level lapse rates. This will result in
high-based storms that could be capable of producing isolated severe
wind gusts and hail. The threat should persist into the evening.

..Broyles/Squitieri.. 03/31/2026


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SPC Mar 31, 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
0740 PM CDT Mon Mar 30 2026

Valid 310100Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID TO UPPER MISSISSIPPI VALLEY...

...SUMMARY...
A few severe thunderstorms with large hail, are expected across
parts of the middle and upper Mississippi River Valley tonight
through early Tuesday morning. Isolated strong to marginally severe
storms could occur farther east into parts of Lower Michigan early
Tuesday morning, and over the Texas South Plains this evening.

...Mid To Upper Mississippi Valley/Upper Michigan...
At mid-levels, flow will remain westerly across much of the central
U.S. tonight, as a subtle shortwave trough moves eastward across the
lower to Mid Mississippi Valley. In response, moisture advection
will increase from the southern and central Plains northeastward
into the Upper Midwest, as a 40 to 50 knot low-level jet strengthens
this evening and overnight. The northern edge of the low-level jet
will be located from Iowa eastward into southern Wisconsin and
northern Illinois, where lift will be maximized. Within this zone,
isolated to scattered thunderstorms are expected to develop this
evening into the overnight period.

On radar, isolated thunderstorms are already ongoing across
east-central Iowa this evening. In the vicinity of this storm, RAP
forecast soundings early this evening show a near surface inversion,
with MUCAPE around 2000 J/kg, effective shear near 40 knots and
700-500 mb lapse rates around 8 C/km. This will be favorable for a
severe threat with cells that initiate later this evening. The
storms will likely be elevated and could become supercells with
potential for large hail. The greatest threat for large hail will be
located along and just to the north of the strongest instability,
from near Des Moines east-northeastward to the vicinity of Chicago
and Milwaukee. Hailstones greater than 2 inches will be possible
with the strongest of supercells. A marginal wind-damage threat may
also develop as convective coverage increases from late this evening
into the overnight period.

Further east into Lower Michigan, scattered convective initiation is
expected by early Tuesday morning. These storms could have an
isolated threat for hail and severe wind gusts, but the threat is
expected to be marginal and more localized due to weaker
instability.

...Southern Plains...
A shortwave trough is evident on water vapor imagery over
west-central Kansas. Lift associated with this feature is
contributing to convective development across the eastern Texas
Panhandle this evening. These storms are located just to the west of
an axis of moderate instability, where MLCAPE is in the 1500 to 2000
J/kg range, according to the RAP. Forecast soundings near Childress
have 0-6 km shear in the 35 to 40 knot range, with very steep low to
mid-level lapse rates near 8.5 C/km. This should be favorable for a
marginal wind-damage threat, with any threat expected to persist for
a couple more hours.

..Broyles.. 03/31/2026


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SPC Mar 30, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Mon Mar 30 2026

Valid 302000Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IOWA
INTO SOUTHERN WISCONSIN...NORTHERN ILLINOIS...AND LAKE MICHIGAN...

...SUMMARY...
A few severe thunderstorms with large hail, are expected across
parts of the middle and upper Mississippi River Valley tonight
through early Tuesday morning. Isolated strong to marginally severe
storms could occur farther east into parts of Lower Michigan early
Tuesday morning, and over the Texas South Plains this afternoon and
evening.

Little change was made to the outlook at 20Z. Storms are still
expected to form near or after 00Z over IA as a weak midlevel wave
moves out of NE, and theta-e advection around 850 mb increases on
the nose of the nocturnal low-level jet. Hail and locally strong
gusts will be possible.

As the increasing moisture spreads farther north overnight, it will
interact with the east-west oriented frontal zone from southern WI
into Lower MI, with additional development expected. Areas of hail
remain possible as lapse rates aloft will be steep. Moderate
deep-layer mean wind speeds should also result in corridors of
strong to damaging gusts as storms amass outflow.

Uncertainty remains regarding coverage of storms overnight.
Conditionally, strong westerly mean wind speeds and presence of dry
air in the low-levels may favor damaging wind gusts, perhaps
crossing Lake MI and into Lower MI overnight should a substantial
cluster of storms remain intact.

..Jewell.. 03/30/2026

.PREV DISCUSSION... /ISSUED 1113 AM CDT Mon Mar 30 2026/

...IA to Lower MI...
Fast zonal flow is present across the northern tier of states today,
with minor perturbations embedded within the flow field affecting
the upper MS Valley and Great Lakes region. A combination of
daytime heating, low-level warm/moist advection, and increasing
low-level convergence along a surface baroclinic zone will result in
scattered thunderstorms after dark over IA. These storms will form
in an environment of steep mid-level lapse rates and strong
deep-layer shear. MLCAPE values around 1500 J/kg will promote
strong updrafts with a few supercells possible. Large hail appears
to be the main threat with these storms as they progress eastward
into northern IL/southern WI and slowly weaken with diurnal cooling.

Storms will persist through the night and spread across much of
lower MI. Despite weak instability, a few CAM solutions maintain
vigorous updrafts, supporting a low risk of hail and gusty winds
overnight.

...TX Panhandle...
Full sunshine and dewpoints in the 50s will yield a moderately
unstable air mass along the dryline over the TX Panhandle this
evening. Most CAM guidance show isolated thunderstorm development
in this region - mainly in the 23-03z period. Forecast soundings
suggest the low/mid troposphere is dry and will limit the number of
updrafts that can survive. However, any storm that can persist will
pose a risk of gusty winds or hail.


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