RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Mon May 11 10:02:01 UTC 2026.
No Mesoscale Discussions are in effect as of Mon May 11 10:02:01 UTC 2026.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1242 AM CDT Mon May 11 2026
Valid 111200Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE COASTAL
CAROLINAS INTO THE FLORIDA PENINSULA...AND ALONG THE CENTRAL GULF
COAST...
...SUMMARY...
Isolated severe storms with locally damaging wind gusts and hail are
possible Monday afternoon from the coastal Carolinas into the
Florida Peninsula, and along the central Gulf Coast.
...Synopsis...
Within the base of broader-scale troughing over eastern North
America, a lead short-wave trough will progress from the TN Valley
through the Carolinas on Monday, in tandem with a mid-level jet
streak. Farther to the southwest, a vorticity maximum over western
TX as of late evening is expected to progress east through the
Sabine River Valley to along the central Gulf Coast Monday afternoon
into Monday night. Elsewhere, a strong short-wave trough and
attending mid/upper-level wind maxima will crest the western U.S.
ridge axis along the International Border before turning more
southeast into the northern Plains and upper MS Valley Monday night
into Tuesday morning.
At the surface, a cold front will settle south through the lower MS
Valley and Southeast with low pressure developing along the boundary
over coastal SC or far southeast NC by early afternoon. Elsewhere,
an area of low pressure will track east-southeast through southern
parts of Saskatchewan and Manitoba with an associated cold front
sweeping southeast through the northern High Plains. A trough will
precede the cold front with that feature shifting east into the
central Dakotas by early evening.
...Coastal Carolinas into the eastern Florida Peninsula...
Latest model guidance is suggestive that surface-based thunderstorm
development may occur as early a mid to late morning along or ahead
of the cold front from the SC piedmont into the coastal plain as
forcing for ascent increases downstream from the approaching
short-wave trough. Subsequent storm development is also expected
farther northeast along the front into southeast NC by late morning
into early afternoon.
Even with the relatively early storm development, forecast soundings
indicate the presence of a moderately unstable warm sector with
MLCAPE approaching 1500 J/kg. Vertical shear will steadily increase
with the arrival mid-level jet streak, such that some transient
supercell structures may evolve, especially in the vicinity of the
weak surface low. The strongest storms will be capable of isolated
occurrences of damaging winds and marginally severe hail into mid
afternoon before moving offshore. Generally weak low-level shear
should limit tornado potential.
Additional strong to marginally severe storms appear possible along
the cold front, as well as the Atlantic Coast sea breeze from
southeast GA southward into the Fl Peninsula. The combination of a
moist and moderately unstable air mass (MLCAPE of 1500-2500 J/kg)
with 30-40 kt of effective bulk shear will be supportive of some
storm organization with an attendant risk for damaging, wet
microbursts and perhaps some marginally severe hail.
...Central Gulf Coast...
Increased forcing for ascent associated with the short-wave trough
moving into the Sabine River Valley is expected to contribute to an
increase thunderstorm development Monday afternoon across southern
parts of LA and MS, potentially into southwest AL. A moist and
moderately unstable air mass will coincide with 30-35 kt of
effective bulk shear, with the 00z convection-allowing models
suggesting some potential for cold pool organization along the
coast. The primary hazard is expected to be locally damaging outflow
winds.
...Northern Plains into Upper Mississippi Valley...
A plume of steep, mid-level lapse rates (7.5-8.5 C/km) will
overspread the northern Plains Monday, downstream from the
approaching short-wave trough. The boundary-layer ahead of the
pre-frontal trough will remain rather dry with dewpoints in the 30s
to perhaps low/mid 40s, which in turn will limit MLCAPE to 200-300
J/kg. Strong, diurnal heating in the vicinity of the surface trough
coupled with increasing height falls aloft may be sufficient to
support isolated, high-based thunderstorms by late afternoon into
early evening with the potential for locally strong wind gusts.
Thunderstorms may tend to increase in areal coverage later Monday
evening into Monday night across the upper MS Valley, aided by a
nocturnally strengthening low-level jet. By that time, the
convection is likely to be elevated and capable of small hail.
No wind/hail probabilities will be assigned to the area at this
time. However, model trends will be monitored for greater air mass
destabilization, which could warrant 5% probabilities and a level
1/Marginal Risk.
..Mead/Weinman.. 05/11/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Mon May 11 2026
Valid 121200Z - 131200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
SOUTHEAST KANSAS AND FAR NORTHEASTERN OKLAHOMA NORTHEASTWARD INTO
NORTHERN ILLINOIS...NORTHWEST INDIANA AND FAR SOUTHEAST WISCONSIN...
...SUMMARY...
Isolated severe storms with strong wind gusts and hail will be
possible on Tuesday from parts of southeast Kansas and far
northeastern Oklahoma northeastward into northern Illinois,
northwest Indiana and far southeast Wisconsin.
...Central Plains/Mid Mississippi Valley/Southwest Great Lakes...
At mid-levels, a shortwave trough and an associated jet streak will
move southeastward through the Upper Midwest on Tuesday. At the
surface, a low will move southeastward across Wisconsin as a cold
front advances southeastward into the mid to upper Mississippi
Valley. Thunderstorms are expected to develop near the front in the
afternoon as surface heating takes place and low-level convergence
becomes more focused. The storms are forecast to move toward an
instability axis located from southeast Kansas to north-central
Illinois. Along this axis of instability, MLCAPE is forecast to
increase into the 500 to 1500 J/kg range by late afternoon with 0-6
km shear mostly in the 45 to 55 knot range. Low-level lapse rates
are also forecast to become steep just ahead of the front. This
environment should be sufficient for an isolated severe threat, with
hail and strong wind gusts possible. The strongest instability and
steepest mid-level lapse rates are forecast to be further southwest
into parts of southwest Missouri and southeast Kansas, where a
locally greater hail threat will be possible in the late afternoon.
..Broyles.. 05/11/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0217 AM CDT Mon May 11 2026
Valid 131200Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY AND CENTRAL APPALACHIANS...
...SUMMARY...
Isolated severe storms will be possible on Wednesday across the Ohio
Valley and central Appalachians.
...Ohio Valley/Central Appalachians...
An upper-level trough will move eastward across the Ohio and
Tennessee Valleys on Wednesday. At the surface, a low will move
eastward across the lower Great Lakes, as a cold front advances
east-southeastward through the Ohio and Tennessee Valleys. Ahead of
the front, surface dewpoints in the lower to mid 50s F will
contribute to weak destabilization by afternoon. MLCAPE near the
instability axis is forecast to peak around 500 J/kg with 0-6 km
shear in the 25 to 35 knot range. This should support a marginal
severe threat during the afternoon as low-level lapse rates become
steep. A few isolated severe wind gusts will be possible.
..Broyles.. 05/11/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0318 AM CDT Mon May 11 2026
Valid 141200Z - 191200Z
...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
At mid-levels, a shortwave ridge is forecast to pass eastward
through the north-central U.S. on Thursday. A shortwave trough is
forecast to move into the Great Plains, with moisture and
instability located in the central Plains. Although most of the
airmass is forecast to be capped during the day, a few storms with
an isolated severe threat will be possible in areas that heat up the
most.
On Friday, a mid-level ridge is forecast to move eastward across the
Great Plains, as a moisture and instability advects northeastward
into the lower to mid Missouri Valley. Isolated to scattered
thunderstorms will be possible within this airmass in the afternoon
and evening. Hail and isolated severe gusts would be the primary
threats.
By Saturday, a wide corridor of moderate instability is forecast to
be in place over the Great Plains. A shortwave trough is forecast to
move into the central U.S. during the afternoon. Ahead of the
shortwave, scattered thunderstorms will be possible from north Texas
northward into Nebraska. Along the western edge of the instability
corridor, steep mid-level lapse rates and moderate deep-layer shear
are forecast. The environment could support large hail, damaging
wind gusts and an isolated tornado threat in the southern and
central Plains where instability, shear and lift are forecast to
become maximized.
...Sunday/Day 7 and Monday/Day 8...
On Sunday, mid-level flow is forecast to be southwesterly over the
central U.S., as a shortwave trough moves into the Great Lakes.
Another shortwave trough is forecast to move into the northern High
Plains. Further south in the southern and central Plains, moderate
to strong instability is forecast to be in place by midday.
Thunderstorm development is expected over parts of this unstable
airmass in the afternoon and evening. Although uncertainty exists
concerning the location of the greatest severe threat, some
solutions suggest potential for a large complex of storms from
eastern Kansas into Missouri. At this time, too much uncertainty
exists for the addition of a severe threat area.
On Monday, a front is forecast to advance southeastward across the
central U.S. Ahead of this front, isolated severe storms will be
possible near an axis of instability in the afternoon and evening.
However, model spread is relatively large concerning the timing of
features at this extended range.
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0151 AM CDT Mon May 11 2026
Valid 111200Z - 121200Z
...CRITICAL FIRE WEATHER AREA FOR PARTS OF EASTERN MONTANA INTO
WEST-CENTRAL NORTH DAKOTA...
...Synopsis...
Along the northern periphery of a large-scale ridge centered over
the West, a robust midlevel trough and accompanying 70-kt westerly
jet streak will advance eastward across MT and ND during peak
heating. In the low-levels, a lee trough will extend southward along
the northern/central Plains, before being overtaken by a cold front
during the evening.
...Northern and Central Plains...
Within the base of the midlevel trough, strong deep-layer westerly
flow will overspread the northern High Plains during the day. Here,
downslope flow trajectories and diurnal heating will result in a
deeply mixed boundary layer along/west of the lee trough --
characterized by surface temperatures in the middle/upper 70s and
20-25 percent RH. Despite the somewhat marginal RH reductions,
downward transport of the high-momentum flow and a tight pressure
gradient will contribute to 20-25 mph sustained west-northwesterly
surface winds (with gusts upwards of 35 mph). The greatest overlap
of these strong/gusty winds and low RH atop receptive fuels is
expected over parts of eastern MT into west-central ND -- where
Critical highlights are in place. A north-northwesterly surface wind
shift will accompany the frontal passage during the evening hours,
though substantial post-frontal RH recovery is expected.
Farther south along the lee trough into the central Plains, more
substantial downslope warming/drying will yield temperatures in the
lower/middle 80s and 15-20 percent RH. These warm/dry conditions
combined with around 15 mph sustained west-southwesterly surface
winds will yield elevated to locally critical fire-weather
conditions, given critically dry fuels here as well.
..Weinman.. 05/11/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0151 AM CDT Mon May 11 2026
Valid 121200Z - 131200Z
...Synopsis...
On the backside of a robust midlevel trough and attendant surface
low moving eastward from the northern Plains into the upper Midwest
and eventually the Great Lakes, strong deep-layer northwesterly flow
will overspread a well-mixed post-frontal air mass over the
upper/middle MO Valley during the day. While RH reductions will be
modest in the post-frontal air mass (around 25-30 percent), 20-25
mph sustained northwesterly surface winds (with higher gusts) will
compensate and support elevated to locally critical fire-weather
conditions -- given dry/receptive fuels. If guidance trends any
lower with RH reductions, a targeted Critical area could eventually
be warranted.
..Weinman.. 05/11/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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