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 Sat May 09 2026
Valid 091630Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN/CENTRAL OKLAHOMA AND WESTERN NORTH TEXAS...
...SUMMARY...
Widely scattered severe thunderstorms capable of producing mainly
large to very large hail and locally damaging winds appear possible
for parts of western/central Oklahoma this afternoon through
tonight. Isolated hail and damaging winds may also occur across
portions of the Gulf Coast states, central High Plains, Great Lakes,
and Mid-Atlantic.
...Southern/Central Plains...
High-based convection is forecast to develop this afternoon across
southeast WY and vicinity as a mid-level shortwave trough progresses
southeastward across the northern/central High Plains. While
low-level moisture is expected to remain quite limited, cool
temperatures aloft and a well-mixed boundary layer will support a
risk for isolated severe wind gusts and perhaps some hail with the
more robust convection. This activity should spread southeastward
across parts of the central High Plains through the afternoon and
evening, while continuing to pose an isolated severe threat.
Low-level moisture is somewhat greater across the southern High
Plains, but still quite shallow per 12Z observed soundings from
OUN/FWD. While large-scale ascent will remain weaker with southward
extent through the day across this region, a surface dryline will
extend across the eastern TX Panhandle vicinity by peak afternoon
heating. Most guidance continues to suggest an uncapped and
moderately unstable airmass will exist along/east of this dryline
across western OK. Isolated to widely scattered thunderstorms may
initiate by late afternoon/early evening. If this occurs, then a few
supercells capable of producing mainly large to very large hail
appear possible. The well-mixed boundary layer and shallow low-level
moisture suggest a low risk for a tornado or two through early
evening, before low-level shear gradually increases through late
evening. There is also a signal for convection to form/spread
southeastward from KS/northern OK into central OK late tonight/early
Sunday morning. If this scenario occurs, then a severe wind threat
may exist with any sustained clusters given a favorable
thermodynamic and kinematic environment.
...Coastal Texas into the Lower Mississippi Valley/Southeast...
A weak mid-level trough over central/east TX late this morning will
continue to move eastward into the western Gulf through this
evening. Stronger convection across deep south TX has recently moved
offshore, but additional thunderstorms may develop this afternoon
across parts of coastal/southeast TX into LA in close proximity to
the mid-level trough. Cool temperatures aloft atop a moist low-level
airmass will support moderate to locally strong instability. This
coupled with sufficient deep-layer shear may foster modest updraft
organization and an isolated risk for large hail and damaging winds
with the stronger cores that form. Across the central Gulf Coast
states, widespread precipitation and ongoing convection has
reinforced the surface front near the coast. Any appreciable risk
for occasional damaging winds should remain along/south of this
convectively reinforced boundary through the afternoon. Therefore,
the Marginal Risk has been adjusted southward with this update.
...Great Lakes...
Beneath upper troughing centered over Ontario, a surface cold front
will advance east-southeastward across the Great Lakes through the
period. Only modest low-level moisture (generally low to mid 50s
surface dewpoints) will be in place ahead of this front from
southeast Lower MI into the lower Great Lakes. Still, strong
mid-level flow may be mixed towards the surface as low-level lapse
rates continue to steepen this afternoon. Accordingly, thunderstorms
that develop along/ahead of the cold front should pose a threat for
at least isolated damaging winds, and perhaps some hail with any
marginal supercell structures. The overall thermodynamic environment
appears too limited to justify greater severe wind probabilities at
this time.
...Mid-Atlantic...
Given ongoing cloud cover and precipitation, confidence remains
fairly low that sufficient instability to support sustained
surface-based convection will exist this afternoon across the
eastern Mid-Atlantic. Still, a low chance for a stronger
thunderstorm or two may focus across parts of NJ and vicinity, where
weak instability should overlap with modest deep-layer shear.
..Gleason/Chalmers.. 05/09/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Sat May 09 2026
Valid 092000Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHWEST
TEXAS AND CENTRAL TO WESTERN OKLAHOMA AS WELL AS PORTIONS OF THE
LOWER GREAT LAKES...
...SUMMARY...
Widely scattered severe thunderstorms capable of producing mainly
large to very large hail and locally damaging winds appear possible
for parts of western/central Oklahoma this afternoon through
tonight. Isolated hail and damaging winds may also occur across
portions of the Texas and Louisiana Gulf Coast, central High Plains,
Great Lakes, and Mid-Atlantic.
...20z Update...
15% wind risk probabilities were introduced to the eastern shore of
Lake Erie downstream of a developing squall line. Although buoyancy
across this region remains fairly weak (around 500 J/kg MLCAPE per
recent mesoanalysis estimates), boundary-layer mixing is noted along
the eastern shore that may facilitate downward momentum transfer as
the squall line moves onshore. Additionally, latest time-lagged
HRRR/RRFS ensembles have shown a consistent signal for 45-60 mph
gusts associated with the line during the late afternoon/evening
hours, hinting that a localized corridor of higher wind potential
may materialize.
...Northern Gulf Coast/Northern Florida...
Severe probabilities along the northern Gulf Coast and across
northern Florida have been reduced based on recent convective
trends. Latest radar/satellite imagery depicts a frontal boundary
pushing south into the northern Gulf with limited MUCAPE noted in
recent mesoanalyses north of the boundary. Across northern FL,
convection developing along the frontal zone has struggled to
maintain intensity - likely owing to marginal forcing for ascent and
poor mid-level lapse rates sampled by a recent 18 UTC JAX sounding.
Severe wind probabilities have largely been adjusted across
northeastern FL to reflect where stronger heating/better buoyancy
will likely support more robust updrafts through late afternoon.
...Eastern Texas Panhandle...
Severe hail/wind probabilities have been adjusted west from western
OK into the eastern TX Panhandle where dewpoints are climbing into
the low/mid 50s and shallow cumulus is beginning to develop along
the dryline. These trends hint that the severe risk may emerge
slightly further west than depicted by previous forecasts and
guidance.
Elsewhere, the forecast remains on track. See the previous
discussion below and MCDs 684, 685, and 686 for additional details.
..Moore.. 05/09/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Sat May 09 2026/
...Southern/Central Plains...
High-based convection is forecast to develop this afternoon across
southeast WY and vicinity as a mid-level shortwave trough progresses
southeastward across the northern/central High Plains. While
low-level moisture is expected to remain quite limited, cool
temperatures aloft and a well-mixed boundary layer will support a
risk for isolated severe wind gusts and perhaps some hail with the
more robust convection. This activity should spread southeastward
across parts of the central High Plains through the afternoon and
evening, while continuing to pose an isolated severe threat.
Low-level moisture is somewhat greater across the southern High
Plains, but still quite shallow per 12Z observed soundings from
OUN/FWD. While large-scale ascent will remain weaker with southward
extent through the day across this region, a surface dryline will
extend across the eastern TX Panhandle vicinity by peak afternoon
heating. Most guidance continues to suggest an uncapped and
moderately unstable airmass will exist along/east of this dryline
across western OK. Isolated to widely scattered thunderstorms may
initiate by late afternoon/early evening. If this occurs, then a few
supercells capable of producing mainly large to very large hail
appear possible. The well-mixed boundary layer and shallow low-level
moisture suggest a low risk for a tornado or two through early
evening, before low-level shear gradually increases through late
evening. There is also a signal for convection to form/spread
southeastward from KS/northern OK into central OK late tonight/early
Sunday morning. If this scenario occurs, then a severe wind threat
may exist with any sustained clusters given a favorable
thermodynamic and kinematic environment.
...Coastal Texas into the Lower Mississippi Valley/Southeast...
A weak mid-level trough over central/east TX late this morning will
continue to move eastward into the western Gulf through this
evening. Stronger convection across deep south TX has recently moved
offshore, but additional thunderstorms may develop this afternoon
across parts of coastal/southeast TX into LA in close proximity to
the mid-level trough. Cool temperatures aloft atop a moist low-level
airmass will support moderate to locally strong instability. This
coupled with sufficient deep-layer shear may foster modest updraft
organization and an isolated risk for large hail and damaging winds
with the stronger cores that form. Across the central Gulf Coast
states, widespread precipitation and ongoing convection has
reinforced the surface front near the coast. Any appreciable risk
for occasional damaging winds should remain along/south of this
convectively reinforced boundary through the afternoon. Therefore,
the Marginal Risk has been adjusted southward with this update.
...Great Lakes...
Beneath upper troughing centered over Ontario, a surface cold front
will advance east-southeastward across the Great Lakes through the
period. Only modest low-level moisture (generally low to mid 50s
surface dewpoints) will be in place ahead of this front from
southeast Lower MI into the lower Great Lakes. Still, strong
mid-level flow may be mixed towards the surface as low-level lapse
rates continue to steepen this afternoon. Accordingly, thunderstorms
that develop along/ahead of the cold front should pose a threat for
at least isolated damaging winds, and perhaps some hail with any
marginal supercell structures. The overall thermodynamic environment
appears too limited to justify greater severe wind probabilities at
this time.
...Mid-Atlantic...
Given ongoing cloud cover and precipitation, confidence remains
fairly low that sufficient instability to support sustained
surface-based convection will exist this afternoon across the
eastern Mid-Atlantic. Still, a low chance for a stronger
thunderstorm or two may focus across parts of NJ and vicinity, where
weak instability should overlap with modest deep-layer shear.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Sat May 09 2026
Valid 101200Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SUNDAY
AFTERNOON THROUGH LATE EVENING ACROSS PARTS OF CENTRAL AND NORTH
TEXAS...
...SUMMARY...
Large hail (some in excess of 2 inches in diameter) and severe
outflow gusts (potentially in excess of 75 mph) will be possible
Sunday afternoon/evening across parts of central and north Texas.
...Southern Plains Sunday afternoon/night...
Within the broader pattern of a Great Lakes trough and Intermountain
ridge, an embedded shortwave trough now over the northern Rockies
will progress southeastward to KS/OK by Sunday afternoon. In the
wake of this shortwave trough and a separate northern stream wave
over the Great Lakes, a surface cold front will move southeastward
across OK/TX. Convection will likely be ongoing at 12z across OK in
the vicinity of the front. There will be some potential for the
overnight convection in OK to continue east-southeastward during the
day into AR/northern LA into MS with the threat for at least
isolated wind damage and large hail.
Additional storm development is likely along the front Sunday
afternoon from the Edwards Plateau into north TX, with the northern
extent of development modulated by morning convection and associated
convective outflow. Convective inhibition will diminish by
early-mid afternoon and MLCAPE will increase to 2500-3000 J/kg as
surface heating (temperatures of 85-90 F) drives deep mixing beneath
an elevated mixed layer with midlevel lapse rates of 8-9 C/km.
Vertical shear will be relatively weak in the open warm sector, with
modest shear enhancement expected along the front and/or lingering
convective outflows in the vicinity of the Red River. Somewhat
discrete convection may occur initially with some supercell
potential, which will drive the potential for isolated very large
hail. The potential for severe outflow gusts will increase with
upscale growth, given the steep lapse rate environment. Storms will
likely reach the TX coast and deep South TX by early Monday morning.
...FL Sunday afternoon/evening...
Strong surface heating across the FL peninsula will likely support
sea breeze thunderstorms Sunday afternoon/evening. The more
probable zone for development will be skewed to the central
peninsula and Atlantic coast given a westerly component to the
low-midlevel flow. Isolated wind damage and marginally severe hail
will be the main threats.
..Thompson.. 05/09/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0205 PM CDT Sat May 09 2026
Valid 111200Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MONDAY AFTERNOON
ACROSS PARTS OF THE SOUTHEAST...
...SUMMARY...
Isolated severe storms with locally damaging wind gusts are possible
Monday afternoon across parts of the Southeast.
...Southeast Monday afternoon...
A surface cold front will move southeastward into the northwest Gulf
early in the period, likely aided by outflow from D2 convection.
Farther east, the front will reach the coast of the Carolinas Monday
afternoon, and the northeast Gulf coast/north FL by late Monday
night or early Tuesday morning. Aloft, a midlevel trough will
progress eastward near the Gulf coast, in advance of the next
digging wave over the northern Plains and upper MS Valley.
Thunderstorms will be possible within the moist environment along
the front. A few strong storms/clusters with wind damage may occur
Monday afternoon along the front, where pockets of stronger surface
heating occur in cloud breaks, coincident with modest enhancement of
midlevel flow/deep-layer shear. Isolated strong storms will also be
possible along the Atlantic coast sea breeze into the FL peninsula.
...Northern Plains to Upper MS Valley Monday afternoon/night...
Low-level moisture will remain limited in advance of a midlevel
trough digging southeastward, around the northeast periphery of a
ridge over the Southwest. Deep surface mixing along the surface
front/trough could support isolated, high-based storms Monday
afternoon across ND. However, the more probable scenario will be
for a few elevated storms to form by Monday evening/night over MN
and adjacent areas of WI/IA where sufficient midlevel
moistening/ascent occurs on the east edge of the steeper midlevel
lapse rates.
..Thompson.. 05/09/2026
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