SPC AC 091630
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
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
SPC AC 091727
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
WUUS02 PTSDY2
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
SPC AC 090720
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0220 AM CDT Mon Mar 09 2026
Valid 111200Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE ARKLATEX
AND LOWER MISSISSIPPI VALLEY NORTHEAST THROUGH THE OHIO VALLEY...
...SUMMARY...
Isolated to scattered severe thunderstorms are possible on Wednesday
from the ArkLaTex and Lower Mississippi Valley northeastward through
the Ohio Valley vicinity.
...East Texas northeast to the Ohio Valley vicinity...
A split-flow regime will continue into Wednesday, with upper
troughing over the central U.S. remaining bifurcated through much of
the period. In the southern branch, a closed low/upper shortwave
trough will migrate from TX to the Lower MS Valley. Meanwhile, the
northern stream upper trough over the northern Plains/Upper Midwest
will develop east across the Upper Great Lakes/Midwest. Ahead of
these features, strong southwesterly deep-layer flow will extend
from east TX into the Mid-Atlantic/New England. At the surface, a
cold front will extend southwest from a surface low over southern
Lower MI into western OK. This front will advance southeast through
the period, becoming oriented from the Mid-Atlantic coast to the
central Gulf coast by Thursday morning.
Strong warm advection ahead of the front will transport Gulf
moisture as far north as the Mid-Atlantic and southern New England.
Ongoing convection is expected ahead of the front across portions of
the ArkLaTex into the Midwest. This, along with the warm advection
regime resulting in widespread cloudiness, lends to uncertainty in
how the downstream airmass will destabilize, especially with
northeast extent into parts of the Ohio Valley vicinity. Somewhat
stronger destabilization is likely across the Lower MS Valley where
richer Gulf moisture will reside. Strong vertical wind profiles will
support damaging wind potential with even modest instability. Linear
convection is the most likely storm mode given deep-layer flow
parallel to the surface boundary and strong large-scale ascent
overspreading the boundary. If discrete cells can form, some tornado
potential will exist closer to a deepening surface cyclone in the
vicinity of the upper Ohio Valley, and perhaps near a secondary
surface low over the lower MS Valley, though this scenario remains
highly uncertain.
..Leitman.. 03/09/2026
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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