RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1113 AM CDT Mon Mar 30 2026
Valid 301630Z - 311200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MIDDLE AND 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 further east into parts of Lower Michigan early
Tuesday morning, and over the Texas South Plains this afternoon and
evening.
...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.
..Hart/Wendt.. 03/30/2026
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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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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Mon Mar 30 2026
Valid 311200Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
GREAT LAKES REGION...
...SUMMARY...
Scattered severe thunderstorms are expected through the day and into
the evening hours Tuesday across parts of the Great Lakes/Midwest.
Damaging gusts and severe hail are the main concerns. Isolated
severe storms may also extend southwestward into parts of the
southern Plains.
...Midwest and Great Lakes Region...
Embedded within the mid-latitude westerlies, a low-amplitude
midlevel wave and accompanying 80-90-kt speed max will advance
eastward from the northern Plains/Manitoba across Ontario and Quebec
through the period. In the low-levels, an east/west-oriented
quasi-stationary warm front will extend from New England westward to
a weak low over lower MI, with a cold front trailing
west-southwestward from the low into the central Plains. In response
to the migratory wave, the surface low will move eastward along the
frontal zone during the day, before the trailing cold front
overspreads the region during the evening/overnight hours.
Showers and thunderstorms will likely be ongoing along the frontal
zone on Tuesday morning, and it is unclear if/when this early-day
activity will diminish, given persistent low-level warm advection
amid deep moisture. Nevertheless, current expectations are that
these storms and/or additional storms will intensify while
spreading/developing east-southeastward across the lower Great Lakes
into the Northeast during the afternoon. Here, upper 50s to lower
60s dewpoints beneath steep midlevel lapse rates/EML will contribute
to at least weak to moderate surface-based buoyancy along/south of
the frontal zone. This buoyancy, coupled with 40-50 kt of effective
shear, will favor organized clusters and the potential for a few
semi-discrete supercells initially -- capable of producing scattered
damaging wind gusts and some large hail. Given clockwise-curved
low-level hodographs, a couple tornadoes cannot be ruled out either,
though this remains more conditional. With time, upscale growth into
several lines/clusters will promote a continued risk of damaging
winds and some embedded tornado risk as storms spread
east-southeastward into the evening/overnight hours. Depending on
boundary-layer recovery, a greater severe risk may materialize from
parts of lower MI into far southwest NY and northwest PA.
...Southern Plains...
Strong diurnal heating amid steep deep-layer lapse rates along a
north/south-oriented dryline should promote isolated thunderstorm
development by late afternoon into the evening. Antecedent dry air
and weak forcing for ascent cast uncertainty on storm coverage.
However, any storms that do form will be capable of producing
isolated large hail and locally severe gusts -- given moderate
surface-based buoyancy and around 20-30 kt of effective shear.
..Weinman.. 03/30/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Mon Mar 30 2026
Valid 011200Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...
...SUMMARY...
Severe thunderstorms are likely across the southern and central
Plains on Wednesday afternoon and evening. Severe wind gusts and
large hail are the primary concerns. Isolated strong/severe storms
are also possible over parts of the upper Ohio Valley into the
Mid-Atlantic.
...Southern and Central Plains...
A large-scale trough accompanied by 40-50-kt midlevel southwesterly
flow will move eastward from the Southwest/Great Basin across the
southern/central Plains through the period. At the same time, a lee
cyclone will deepen and track eastward across the central Plains,
while a southward-extending dryline makes little eastward
progression over the southern Plains. Ample diurnal heating and
parallel low-level flow to the dryline will support scattered
thunderstorm development by late afternoon as inhibition at the base
of the EML erodes. As the enhanced midlevel flow accompanying the
trough overspreads the dryline, effective shear should increase to
around 40 kt. The elongated hodographs and moderate surface-based
buoyancy should initially support semi-discrete supercells with a
risk of large hail and locally severe gusts. Soon after,
strengthening forcing for ascent preceding the trough should promote
upscale growth into clusters/lines and could develop into a severe
MCS. This would favor an increasing risk of severe gusts (some 75+
mph possible). Confidence in this scenario is currently highest over
parts of west/central OK into north TX, where a SLGT Risk was added.
...Ohio Valley to the Mid-Atlantic...
Despite weak large-scale forcing for ascent, diurnal heating amid
upper 50/lower 60s dewpoints and relatively steep lapse rates should
support isolated to widely scattered thunderstorms along and south
of a stationary front draped across the area. Sufficient
surface-based buoyancy and around 30 kt of effective shear will
support a couple organized storm clusters with a risk of damaging
winds and isolated hail.
..Weinman.. 03/30/2026
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