RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat May 9 16:34:01 UTC 2026.
No Mesoscale Discussions are in effect as of Sat May 9 16:34:01 UTC 2026.
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0703 AM CDT Sat May 09 2026
Valid 091300Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
WESTERN/CENTRAL OKLAHOMA...
...SUMMARY...
Widely scattered severe thunderstorms capable of large to very large
hail, locally damaging wind gusts, and perhaps a few tornadoes are
possible in parts of western into central Oklahoma Saturday
afternoon and evening. Sparser large hail and damaging wind
occurrences are possible across the Gulf Coast states, the northern
and central High Plains, the Great Lakes, and possibly mid-Atlantic.
...Plains...
A flat upper ridge will be present today over the southwest states
and southern Rockies, while stronger flow aloft extends from the
northern Rockies into the mid MS Valley and eastern states. The
cold front that triggered convection over OK on Friday has stalled
over north TX and will slowly return northward through the day
today. Despite relatively weak low-level winds, dewpoints will
climb through the 50s across western OK leading to an axis of
moderate CAPE by late afternoon. Strong heating along/behind a
diffuse dryline will likely lead to isolated thunderstorm
development. Steep mid-level lapse rates and strong deep-layer
shear will promote supercell storm structures capable of large hail.
Given the weak forcing aloft, storm coverage is likely to be rather
sparse through the evening. But those storms that can persist will
be in a progressively more moist and sheared environment that could
support the risk of a tornado or two.
Elsewhere farther north, steep low and mid-level lapse rates will
promote a risk of scattered high-based afternoon thunderstorms
capable of gusty winds and hail from eastern WY/CO into western
NE/KS.
...Gulf Coast...
Clusters of thunderstorms are ongoing this morning over parts of
LA/MS/AL. This activity will persist through the day and spread
eastward. Limited heating and rather weak shear profiles will limit
the overall severe threat. But nevertheless a few storms may
occasionally become intense - capable of gusty/damaging winds and
hail.
...Lower Great Lakes and Mid Atlantic...
A large upper trough will track from Ontario into Quebec today,
while the associated cold front sweeps southeastward across the
lower Great Lakes region. Sufficient instability is forecast to
support a line of thunderstorms forming over Lakes Erie/Ontario and
spreading into parts of OH/PA/NY this evening. Gusty winds and
small hail are expected, with a few reports of severe wind/hail
possible.
A corridor of moderate surface heating will extend from central VA
into NJ today, helping to destabilize this region and lead to widely
scattered afternoon thunderstorms. CAM solutions suggest the storms
that form will struggle to organize/intensify, but there will be
sufficient CAPE/shear to support some risk of a damaging wind gust
or two through early evening.
..Hart/Wendt.. 05/09/2026
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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 Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1123 AM CDT Sat May 09 2026
Valid 091700Z - 101200Z
...Northern Plains...
Existing elevated fire weather highlights over much of western ND
were expanded southward towards the ND/SD border based on latest
short term forecast guidance. Sustained northwest winds of 15-20 mph
in a modestly dry (RH between 20-30% by this afternoon) post-frontal
environment should yield several hours of elevated fire weather
conditions for far northeastern MT and much of western ND southward
to the ND/SD border. Fuels remain very dry and supportive of
wildfire growth, despite the cooler post-frontal air mass
infiltrating into the Northern Plains. Otherwise, the forecast
remains largely on track, please see previous discussion for more
details.
..Williams.. 05/09/2026
.PREV DISCUSSION... /ISSUED 0158 AM CDT Sat May 09 2026/
...Synopsis...
Between a large-scale ridge over the West Coast and broad upper
troughing over the eastern two-thirds of the CONUS, a belt of
enhanced deep-layer northwesterly flow will overspread a dry
post-frontal air mass over the northern Plains. Over parts of
western/central ND, diurnal heating will result in a well-mixed
boundary layer with 20-30 percent RH amid 15-20 mph sustained
northwesterly surface winds. This overlap of modestly dry/breezy
conditions over critically dry/receptive fuels will favor elevated
fire-weather conditions. The Elevated highlights are generally
bounded by cooler temperatures/higher RH to the east, expected cloud
coverage to the west (accompanying a passing shortwave trough), and
a band of ongoing precipitation across southern ND.
Farther west, areas of dry/windy conditions are expected across
parts of the Great Basin into the Southwest. While locally elevated
conditions will be possible, fuels are generally unsupportive of
large fires at this time.
...Please see www.spc.noaa.gov/fire for graphic product...
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