RSS Mesoscale Discussions from Storm Prediction Center
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 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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