RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon Mar 09 2026
Valid 091630Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FROM ARKANSAS TO NORTHWEST GEORGIA...
...SUMMARY...
Large hail, damaging winds and a couple of tornadoes are possible
this afternoon/evening from the Mid-South into northwest Georgia.
...AR to north GA this afternoon/evening...
A weak mid-upper speed max is cresting the larger-scale ridge and
will move from AR to the TN Valley this afternoon/evening.
Associated/ongoing convection across AR will likely persist through
the afternoon with some tendency for upscale growth, while spreading
eastward along the northern gradient of boundary-layer dewpoints in
the low-mid 60s. Surface heating in cloud breaks, beneath the
eastern extent of 7-8 C/km midlevel lapse rates, will contribute to
moderate buoyancy (MLCAPE of 1000-1500 J/kg) along this corridor
with minimal convective inhibition.
Deep-layer vertical shear will be sufficient for a somewhat
organized/bowing storm cluster to evolve from the ongoing AR storms
as they spread across the TN Valley this afternoon, potentially
reaching northwest GA by late evening. The initial storms in the
cluster will pose a threat for large hail (1-2"diameter), with some
increase in the threat for wind damage from northern MS across
northern AL/northwest GA. More discrete storms will be possible
immediately south of the MCS path this afternoon/evening as a
maritime tropical air mass (68-72 F dewpoints) spreads inland. Wind
profiles will support supercells capable of producing large hail
(some could exceed 2 inches in diameter). A modest increase in
low-level shear this afternoon, combined with rich low-level
moisture and the possibility of lingering convective outflow from
the ongoing storms in AR will also support the potential for a
couple of tornadoes.
Isolated thunderstorm development may also occur farther southwest
along the marine warm front into southeast TX, where there is a
conditional threat for large hail.
...Southern AZ this afternoon/evening...
High-based, low-topped convection is expected in the band of ascent
immediately north-northeast of the closed low near northern Baja.
Low-level moisture will be somewhat limited, but steep low-midlevel
lapse rates and substantial south-southeasterly deep-layer shear
will support a few storms/clusters capable of marginally severe hail
and gusts approaching 60 mph.
..Thompson/Chalmers.. 03/09/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0239 PM CDT Mon Mar 09 2026
Valid 092000Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
ARKANSAS EAST-SOUTHEASTWARD INTO WESTERN AND CENTRAL ALABAMA...
...SUMMARY...
Large hail, damaging winds and a couple of tornadoes are possible
this afternoon/evening from the Mid-South into northwest Georgia.
...20Z Update...
Two changes have been made to the outlook for this issuance. The
first change is to trim southeast Oklahoma mostly out of thunder,
and completely out of the hail and wind probabilities. The second
change is to add thunder across parts of South Carolina and Georgia.
..Broyles.. 03/09/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Mar 09 2026/
...AR to north GA this afternoon/evening...
A weak mid-upper speed max is cresting the larger-scale ridge and
will move from AR to the TN Valley this afternoon/evening.
Associated/ongoing convection across AR will likely persist through
the afternoon with some tendency for upscale growth, while spreading
eastward along the northern gradient of boundary-layer dewpoints in
the low-mid 60s. Surface heating in cloud breaks, beneath the
eastern extent of 7-8 C/km midlevel lapse rates, will contribute to
moderate buoyancy (MLCAPE of 1000-1500 J/kg) along this corridor
with minimal convective inhibition.
Deep-layer vertical shear will be sufficient for a somewhat
organized/bowing storm cluster to evolve from the ongoing AR storms
as they spread across the TN Valley this afternoon, potentially
reaching northwest GA by late evening. The initial storms in the
cluster will pose a threat for large hail (1-2"diameter), with some
increase in the threat for wind damage from northern MS across
northern AL/northwest GA. More discrete storms will be possible
immediately south of the MCS path this afternoon/evening as a
maritime tropical air mass (68-72 F dewpoints) spreads inland. Wind
profiles will support supercells capable of producing large hail
(some could exceed 2 inches in diameter). A modest increase in
low-level shear this afternoon, combined with rich low-level
moisture and the possibility of lingering convective outflow from
the ongoing storms in AR will also support the potential for a
couple of tornadoes.
Isolated thunderstorm development may also occur farther southwest
along the marine warm front into southeast TX, where there is a
conditional threat for large hail.
...Southern AZ this afternoon/evening...
High-based, low-topped convection is expected in the band of ascent
immediately north-northeast of the closed low near northern Baja.
Low-level moisture will be somewhat limited, but steep low-midlevel
lapse rates and substantial south-southeasterly deep-layer shear
will support a few storms/clusters capable of marginally severe hail
and gusts approaching 60 mph.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 PM CDT Mon Mar 09 2026
Valid 101200Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
ILLINOIS INTO NORTHWEST INDIANA AND ACROSS THE EDWARDS PLATEAU INTO
CENTRAL TEXAS...
...SUMMARY...
Scattered severe thunderstorms are forecast on Tuesday from the
southern Plains into the southern Great Lakes vicinity. All severe
hazards are possible.
...Synopsis...
A bi-modal severe weather event is expected Tuesday afternoon and
evening across the Mid-West and portions of central Texas.
Mid-morning surface observations/analyses reveal a surface low
migrating eastward across the upper Great Lakes with a trailing cold
front draped southwestward into the central Plains. Weakening winds
behind the front suggest that this boundary will begin to stall
later today across the Midwest/central Plains. Meanwhile, returning
moisture is forecast to spread north over the next 24 hours as
surface pressure falls and southerly winds increase across the
Plains with the approach of the upper trough currently meandering
over Baja California and a slight amplification of the upper wave
over the north-central CONUS. This will help establish an expansive
warm sector from southern Texas northward into the central Plains
and Great Lakes region, bounded to the north by the stalled frontal
boundary and to the west by a weak dryline/Pacific front. Strong to
severe thunderstorms are expected within this warm sector as ascent
along the Midwest frontal zone and across the southern Plains
increases with the ejection of the upper trough late Tuesday
afternoon into Tuesday night.
...Midwest...
The greatest regional severe threat will likely be focused along the
frontal boundary Tuesday afternoon and evening. Most guidance
suggests the stalled cold front will advance northward as a warm
front as low-level southerly flow increases within the warm conveyor
belt of a developing cyclone over IA/northern MO, but the exact
placement and orientation of the boundary, and any potential
influence by cool lake-breezes off lower Lake Michigan, remain
uncertain given spread between 12z CAM and global guidance.
Regardless, strong isentropic ascent over the frontal zone coupled
with ample low-level moistening and steepening mid-level lapse rates
will support a convective environment favorable for well-organized
convection along both the warm front and southwestward along the
cold front across northern MO and KS. Effective SRH on the order of
200-300 m2/s2 coupled with MLCAPE of 1500-2000 J/kg along/just south
of the boundary will support the potential for tornadoes - including
strong tornadoes - with any discrete supercell that can become
established. Convection developing north of the surface fronts will
still reside in a very favorable environment for elevated supercells
capable producing large/very large hail (possibly in excess of 2
inches). Upscale growth/clustering is expected through the evening
hours, which should support an increase in severe winds. It remains
somewhat unclear how quickly upscale growth will occur given
along-boundary flow through a deep layer, and this may curtail the
supercellular tornado threat if clustering occurs too quickly.
However, based on latest forecast soundings and CAM guidance, the
tornado potential will likely be greatest along the warm front
across central IL between 21-02 UTC where low-level SRH and surface
pressure falls/ascent will be maximized.
...Southern Plains...
12 UTC soundings across the southern Plains sampled steep mid-level
lapse rates already in place across the region. The onset of deep
moisture return is noted along the TX Coastal Plain, which should
spread north across central TX into OK by Tuesday morning.
Isentropic ascent within the warm sector may support isolated
thunderstorm development by late morning across north TX into the
Texarkana region where capping should be weaker. By late
afternoon/early evening, more widespread thunderstorm development is
expected across central TX as strong height falls associated with
the ejecting upper wave overspread the region. Initially discrete
supercells will be capable of all hazards, through very large (2+
inch) hail appears to be the most probable threat. Strong forcing
for ascent will promote upscale growth through the evening with one
or more bowing segments possible. Enlarging low-level hodographs
associated with an increasing nocturnal jet may support embedded
circulations within the developing squall line. 30% hail/wind
probabilities were introduced to highlight the corridor of higher
hail/wind threat from the Edwards Plateau into central TX.
..Moore.. 03/09/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0225 PM CDT Mon Mar 09 2026
Valid 111200Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS
AND THE LOWER MISSISSIPPI RIVER VALLEY INTO THE OHIO RIVER VALLEY...
...SUMMARY...
Isolated to scattered severe thunderstorms are expected on Wednesday
from the ArkLaTex and Lower Mississippi Valley northeastward through
the Ohio Valley vicinity.
...Synopsis...
Strong to severe thunderstorms are probable across an expansive warm
sector stretching from the Gulf Coast northward into the upper Ohio
Valley region. The amplification of an upper wave over the northern
CONUS will support steady intensification of a surface cyclone as it
migrates from the Great Lakes region into southeast Quebec by 12 UTC
Thursday. An attendant cold front will push across the MS Valley
into the upper OH Valley and Southeast states during the forecast
period, and will act as the primary foci for thunderstorm
development.
...East Texas into the Lower MS Valley...
Thunderstorm clusters and/or convective bands will likely be
ongoing, albeit weakening, across the eastern TX/OK at the start of
the forecast period. A combination of daytime heating, ascent ahead
of a southern-stream upper trough, and forcing along the approaching
cold front should promote an uptick in convective intensity and
coverage by late morning/early afternoon across LA and MS.
Storm-motion vectors largely along the front will maintain a linear
storm mode and support primarily a severe wind threat. The severe
threat may be maximized during the late morning/early afternoon
hours as buoyancy increases but before low to mid-level flow
decreases as the synoptic low accelerates away to the northeast.
...OH Valley...
Low-level moisture and a remnant EML will continue to spread
north/northeast in tandem with the translation of the surface low.
This should support adequate buoyancy within a narrow, but
migratory, warm sector for surface-based convection. Strong flow in
proximity to the surface low/upper jet will promote organized
convection along the front, most likely organized clusters and lines
capable of severe gusts and perhaps embedded circulations. Recent
extended-range RRFS solutions hint at the development of pre-frontal
supercells within a diffuse plume of low-level theta-e advection
across the upper OH Valley. Forecast soundings from this region
suggest that tornadic supercells are possible. Other guidance also
depicts this plume of theta-e advection, which lends some credence
to this scenario. However, the RRFS is typically overly aggressive
with convective intensity, and recent MPAS solutions are less
bullish on deep convection ahead of the front where mostly cloudy
skies should limit diurnal insolation to some degree. This
uncertainty precludes the introduction of higher risk probabilities,
but trends will be monitored for a more robust severe threat within
this regime.
..Moore.. 03/09/2026
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