RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0734 AM CDT Mon Mar 09 2026
Valid 091300Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE ARKLATEX
AND MID-SOUTH INTO THE SOUTHEAST...
...SUMMARY...
Severe thunderstorms are possible from the Arklatex and Mid-South
through the Southeast.
...Synopsis...
Early-morning satellite imagery shows a low-amplitude shortwave
trough moving through the TX Panhandle, embedded within the westerly
flow aloft well downstream from an upper low off the Baja California
Coast. This shortwave trough is forecast to progress eastward
throughout the day, reaching the Mid-South by this evening and the
southern Appalachians by early tomorrow. Enhanced mid-level flow
(i.e. 500 mb winds around 50 kt) will accompany this wave, spreading
eastward in tandem with the progression of the wave.
Recent surface analysis shows a relatively moist airmass already in
place from the southern Plains through much of the Southeast. Mid
60s dewpoints currently extend from the TX Coastal Plain through
east TX and over much of LA. This moist airmass is expected to
advect quickly northward/northeastward throughout the day, largely
in response to strengthening low to mid-level flow downstream of the
increasing westerlies across the Plains. Ascent attendant to the
embedded shortwave coupled with the increasing moisture and buoyancy
will likely result in thunderstorm development from the Arklatex and
Mid-South through much the Southeast.
...Arklatex/Mid-South through the Southeast...
A diffuse stationary front currently extends from east-central OK
into northern AL before shifting more northeastward across eastern
TN. Modest warm-air advection is ongoing throughout the western
portion of this boundary, supported by the increasing low to
mid-level flow just ahead of the shortwave trough mentioned in the
synopsis. Isolated thunderstorms have already developed across
southeast OK, and this is likely the beginning of a thunderstorm
cluster that is expected to develop from the Arklatex into the
Mid-South vicinity this morning. Steep mid-level lapse rates and
moderate vertical shear suggest some hail is possible with this
early activity. Recently issued MCD #0177 provides additional
information for this early morning activity.
Most of the guidance suggests that the resulting thunderstorm
cluster becomes increasingly organized with time, growing upscale
into an MCS before then progressing across northern MS and northern
AL. The preceding airmass should be moderately moist and buoyant,
with dewpoints likely in the mid 60s and MLCAPE around 1000 to 1500
J/kg. Moderate vertical shear should be in place as well, with the
resulting conditions supportive of MCS maintenance through the
afternoon. The same conditions will support robust updrafts capable
of large hail and damaging gusts. Additional, more cellular activity
is possible in the wake of the main MCS, with conditions remaining
favorable for hail. Overall tornado potential appears to be limited
by the likely linear mode as well as the relatively weak low-level
flow. Even so, the modest low-level curvature expected supports a
low-probability tornado threat.
...Southern AZ...
A strong upper low is forecast to advance toward the northern Baja
Peninsula by 10/00z before shifting into northwest Mexico by the end
of the period. Steep lapse rates are forecast across southern AZ
within a favorable zone for large-scale ascent. Thermodynamic
profiles suggest scattered convection will develop and spread north
across this region. Forecast soundings show limited buoyancy,
suggesting this activity should struggle to attain severe levels.
Even so, small hail and gusty winds could accompany the strongest,
most persistent updrafts.
..Mosier/Dean.. 03/09/2026
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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 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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