RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Wed May 13 17:25:02 UTC 2026.
MD 0711 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST PA...SOUTHEAST OH...AND PARTS OF WV
Mesoscale Discussion 0711
NWS Storm Prediction Center Norman OK
1141 AM CDT Wed May 13 2026
Areas affected...southwest PA...southeast OH...and parts of WV
Concerning...Severe potential...Watch unlikely
Valid 131641Z - 131915Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated strong wind gusts and hail are possible this
afternoon. A severe thunderstorm watch is unlikely at this time.
DISCUSSION...Thunderstorms are developing near and just ahead of a
surface cold front from far western NY into eastern OH. Pockets of
stronger heating have occurred ahead of this activity across
southwest PA into OH and parts of WV where some clearing has
occurred in the wake of early day cloudiness and showers. This has
allowed temperatures to warm into the low/mid 60s amid 50s
dewpoints. While boundary layer moisture will remain modest, cold
temperatures aloft will support steepened midlevel lapse rates. As a
result, modest destabilization is underway within a narrow corridor
ahead of the front. Instability is likely to remain modest, with
generally less than 750 J/kg MLCAPE expected by peak heating. While
upper level flow will be moderate, low-level flow is expected to be
somewhat less compared to further north closer to the surface low.
In fact, forecast guidance indicates 850 mb flow will weaken through
the day. Nevertheless, effective shear magnitudes will be sufficient
for some organized storm structures. However, limited instability
and modest boundary layer moisture will likely preclude more
substantial severe potential. Locally strong wind gusts and
marginally severe hail will be possible with the strongest cells,
but overall severe is expected to remain sparse, negating watch
issuance at this time.
..Leitman/Mosier.. 05/13/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CTP...LWX...PBZ...RLX...CLE...
LAT...LON 41228031 41027968 40987875 40837840 40407835 39927858
39127936 38598013 38218092 38078132 38158182 38348209
38658226 39038215 40188139 41228031
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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MD 0710 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF WESTERN/CENTRAL NY INTO NORTHERN/WESTERN PA
Mesoscale Discussion 0710
NWS Storm Prediction Center Norman OK
1056 AM CDT Wed May 13 2026
Areas affected...portions of western/central NY into
northern/western PA
Concerning...Severe potential...Watch unlikely
Valid 131556Z - 131830Z
Probability of Watch Issuance...5 percent
SUMMARY...A band of thunderstorms may bring locally gusty winds and
small hail to portions of western/central New York into western and
northern Pennsylvania this afternoon. A severe thunderstorm watch is
not expected.
DISCUSSION...Thunderstorms are beginning to develop just ahead of a
surface cold front from far western NY into northeast OH. While 12z
regional RAOBs and current regional VWPs indicate 30-40 kt
west/southwesterly flow in the 1-3 km range, instability remains
scant. Lingering cloudiness will limit stronger heating and
boundary-layer moisture is expected to remain modest this afternoon.
However, cold temperatures aloft will support modestly steep
midlevel lapse rates. As a result, a narrow band of weak MLCAPE
(less than 500 J/kg) is forecast just ahead of the cold front. This,
along with sufficient deep layer flow, should allow for an organized
band of thunderstorms developing eastward across the region this
afternoon. Given cool surface temperatures, poor low-level lapse
rates, and limited instability, overall severe potential appears
low. However, given the strength of deep layer flow and cold
temperatures aloft, the strongest cells could produce locally gusty
winds and perhaps small hail through the afternoon.
..Leitman/Mosier.. 05/13/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BGM...BUF...CTP...PBZ...CLE...
LAT...LON 43007727 43367625 43357573 43227550 42347587 41557688
41277735 40927833 40907971 41048023 41178028 41288029
41418016 43007727
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1120 AM CDT Wed May 13 2026
Valid 131630Z - 141200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MT
SOUTHWARD INTO NORTHERN UT...
...SUMMARY...
Scattered thunderstorms capable of damaging wind gusts are possible
from the Great Basin into northern Rockies this afternoon and
evening. Other areas of isolated severe wind/hail risk may occur
over the upper Ohio Valley and the Texas Panhandle.
...WV/PA/NY...
Recent surface analysis places a low over northern Lake
Huron/central Ontario, with a cold front extending back
southwestward through western OH and western KY. Current satellite
shows the associated shortwave trough extending from central Ontario
into the Mid MS Valley. This imagery also shows two embedded
vorticity maxima, one near the surface low over central Ontario and
the other farther southwest over IL/IN. This shortwave is expected
to mature throughout the day, trending towards a more neutral tilt
by this evening, while also gradually shifting eastward. The
associated cold front is forecast to shift quickly eastward as well.
At least scattered clouds will likely persist throughout the day,
somewhat tempering the overall daytime heating. Even so, modest
low-level moisture (i.e. dewpoints in the low/mid 50s) ahead of the
cold front will support a corridor of sufficient buoyancy for
thunderstorm development ahead of the front from western PA and WV
eastward across PA and into southern/central NY. Linear forcing
along the front and relatively modest deep-layer shear will favor a
multicellular line segment mode. Potential exists for a few deeper
updrafts capable of damaging gusts, but the limited heating ahead of
the front, modest buoyancy, and displacement south and east of the
stronger low to mid-level flow should keep the overall severe
potential isolated. A few isolated instances of hail are possible
early in the convective cycle before the more linear structures
dominate.
Recently issued MCD #0710 addresses this area as well.
...Great Basin into the northern Rockies...
Current satellite imagery shows a well-defined, negatively tilted
shortwave trough progressing across the Pacific Northwest. This wave
is forecast to continue eastward through ID and MT today. Strong
heating and deep boundary-layer mixing is expected ahead of this
wave from the Great Basin into the northern Rockies. At the same
time, mid-level moisture associated with the wave will advect
eastward/northeastward, resulting in large area of deep inverted-v
thermodynamic profiles that are also buoyant enough to support
convection and isolated lightning. Strong mid-level flow will
accompany the shortwave, with moderate mid-level flow extending
southward from the primary wave through UT and far western CO.
Scattered convection is expected as lift associated with the wave
begins to interact with this destabilizing airmass, likely starting
around 20/21Z from western MT into northern UT. This convection,
which should include lightning-producing updrafts, will then spread
eastward/northeastward with time. Strong to severe gusts are
possible across this entire region, with the highest likelihood for
severe gusts from central/southern ID into central MT where the
strongest mid-level flow is expected.
...TX Panhandle...
Deep boundary-layer mixing is anticipated across the TX Panhandle
today, with temperatures climbing into the 90s. Low-level moisture
advection should result in higher dewpoints across the eastern
Panhandle, with the resultant dryline acting as a focus for
convergence and attempts at convective initiation. The overall
environment does not look conducive for initiation and majority of
the CAMs do not show storm development. However, any storm that can
persist in this environment would conditionally pose a threat of
damaging wind gusts and large hail.
..Mosier/Chalmers.. 05/13/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1222 PM CDT Wed May 13 2026
Valid 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
CENTRAL AND EASTERN KANSAS...
...SUMMARY...
Thunderstorms with large hail and severe wind gusts are expected on
Thursday across parts of central and eastern Kansas, with more
isolated severe storms possible over parts of the lower Missouri
Valley, northern Ozarks and southern High Plains.
...Synopsis...
Prominent mid-level ridging over the central US is forecast to
weaken and shift eastward Thursday as a flanking upper low moves
eastward toward the Atlantic Coast. A second upper trough, and
associated southern stream shortwave, will move out of the Rockies
and into the Plains Thursday afternoon/evening. Ascent from this
trough will deepen a lee trough into a surface low over the central
High Plains, south of a cold front advancing through the upper
Midwest. Strengthening southerly flow ahead of the lee low will
allow destabilization and increased thunderstorm chances along a
trailing dryline from the central Plains to the southern High
Plains.
...Central KS into the MO and central MS Valley...
As the southern lee low deepens ahead of the southern stream
shortwave trough, a narrow corridor of low-level moisture will
quickly return northward into central KS. Model guidance varies
considerably on the depth and quality of the low-level moisture.
However, dewpoints in the upper 50s to low 60s F appear plausible by
late afternoon and continuing to increase into the evening. This, in
combination with ascent and steepening mid-level lapse rates, will
support moderate destabilization (1500-2500 J/kg MLCAPE) along the
dryline/triple point. Low-level southerly flow, veering to 40-50 kt
in the mid-levels and orthogonal to the dryline will promote
supercell wind profiles.
While capping is expected to remain fairly strong, casting some
uncertainty on storm coverage, ascent from the approaching shortwave
trough along with diurnal heating should remove inhibition.
Convective development is possible near the surface low, or
originating within the more deeply mixed air mass to the west of the
dryline, by late afternoon/early evening. Large hail would be likely
initially, along with some potential for severe wind gusts given the
dry boundary layer. As these storms encounter the increasing surface
moisture, gradual intensification of a few supercells is possible.
The increase in the low-level jet after 00z could support additional
development, while also increasing low-level shear. A tornado is
possible with any supercells able to remain discrete near sunset
given 0-1 km SRH of 200-400 m2/s2.
Eventually, storms should congeal into a cluster and spread eastward
into MO and the mid MS Valley overnight. Some hail and damaging gust
threat remain possible into early D3/Friday.
...Southern and central High Plains...
To the west of the dryline, robust heating and deep vertical mixing
should support the development of weak instability atop a relatively
dry boundary layer. By mid afternoon, high-based showers and
thunderstorms are expected from eastern CO, western KS into parts of
the OK/TX Panhandles and eastern NM. While buoyancy appears quite
limited (~500 J/kg MUCAPE), nearly dry adiabatic lapse rates in the
lowest 3 km will likely support stronger downdrafts with scattered
showers/thunderstorms. Isolated severe wind gusts are possible given
the dry sub cloud layer.
..Lyons.. 05/13/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1146 AM CDT Wed May 13 2026
Valid 131700Z - 141200Z
...CRITICAL FIRE WEATHER AREA FOR NORTHEASTERN MONTANA INTO FAR
NORTHWESTERN NORTH DAKOTA...
...Northeastern Montana...
Virga showers are currently moving through central MT ahead of a
sharp mid-level short wave, with little to no impact on surface
conditions. Southeasterly winds ahead of a deepening lee trough
across southern Alberta into north-central MT will continue to
increase the afternoon, reaching 20-25 mph by the peak afternoon
heating. Current RH of 20-25% will fall into the 15-20% range by
this afternoon. The dry and breezy conditions atop receptive fuels
will yield a critical fire weather threat for much of northeastern
MT.
The mid-level short wave, associated jet streak and increasing
mid/upper level moisture pushes into western/central MT by this
afternoon, supporting high-based showers and thunderstorms across
portions of the northern Rockies and central MT. A dry, sub-cloud
boundary layer will inhibit significant rainfall accumulation within
the fast moving thunderstorm cores as well as promoting strong to
severe downburst winds. Latest forecast guidance suggests a
prolonged convective event, lasting into the evening, affecting much
of northeastern MT. Fuels remain more receptive across northern MT
which could support some lightning ignitions as high-based
thunderstorms move into the northern High Plains this evening.
Therefore, Isolated Dry Thunderstorm Highlights have been extended
into northeastern MT.
A broad fire weather threat remains across much of the Intermountain
West and portions of the Great Plains as the vigorous upper wave
across the Northern Rockies translates eastward. Please see previous
discussion for more details.
..Williams.. 05/13/2026
.PREV DISCUSSION... /ISSUED 1238 AM CDT Wed May 13 2026/
...Synopsis...
A robust upper-level short wave trough and associated increased
west-southwest flow aloft will enter the Pacific Northwest and
Northern Rockies today. Wedged between western U.S. troughing and an
amplifying longwave trough over the eastern U.S., upper ridging will
slide over the Rocky Mountain region. Associated with the
substantial mid-upper level pattern, a rapidly evolving lee-side low
in the southern Canadian Prairies will deepen lee surface troughing
over the Great Basin and High Plains while southwesterly flow ahead
of the trough increases. This will present a multifaceted fire
weather setup across portions of the Intermountain West.
...Northern Montana...
Deepening surface troughing across the southern Canadian Prairies
into central MT will usher in stronger southerly to southeasterly
winds of 15-20 mph along with RH reductions of 20-30 percent,
promoting broad Elevated fire weather concerns. Critical highlights
were maintained where an alignment of RH of 20 percent or below and
winds of 20-25 mph are expected across northeastern MT and far
western ND atop receptive fuels. Increasing mid-level moisture ahead
of the upper trough and arrival of a Pacific cold front should
promote isolated to scattered showers and initially high-based
thunderstorms across much of northwestern MT Wednesday where IsoDryT
highlights have been maintained.
...Southwest, Upper Snake River Plain and Colorado River Basin...
As the sharp upper trough and associated mid-level jet shifts over
ID into western MT, deepening surface troughing across the northern
Great Basin and stronger southwesterly flow ahead of the trough will
bring expansive fire weather concerns to much of the Intermountain
West. Dry and breezy southwesterly flow of 15-25 mph (localized 30
mph in the eastern Great Basin) and RH of 10-15 percent will align
with drying fuels to promote elevated fire weather conditions across
portions of the Great Basin and CO River Basin into central WY.
Forecast thermodynamic profiles (with a prominent dry boundary
layer) will support isolated high-based showers and thunderstorms
over higher terrain of western NM, far eastern AZ, central UT, and
southwest WY into the Upper Snake River Plain. Various stages of
green up and mixed curing fuels has resulted in a complicated
fuelscape, resulting in expansive Elevated highlights and a broader
IsoDryT risk area.
...Please see www.spc.noaa.gov/fire for graphic product...
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