RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1249 AM CDT Thu Jun 18 2026
Valid 181200Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM KENTUCKY INTO
THE MID ATLANTIC...OVER MUCH OF THE NORTHEAST...AND ALONG THE
NORTHERN GULF COAST...
...SUMMARY...
Isolated to scattered severe thunderstorms will be possible from
Kentucky to the Mid-Atlantic, with primarily damaging wind gusts or
marginal hail. Scattered severe storms are possible from upstate New
York into New England, with damaging gusts or even a tornado. A few
tornadoes may occur over parts of the Gulf Coast states, and
scattered storms may produce gusty winds or marginal hail from
Oklahoma into northwest Texas.
...From KY into the Mid Atlantic...
Moderate mid to high level westerlies will exist from the OH Valley
to Mid Atlantic, south of the primary wave over the Northeast. This
region will be south of the midlevel drying, with ample low-level
moisture remaining in place ahead of the slower moving portion of
the front. Scattered storms may be ongoing early in the day from KY
into WV, with perhaps wind or even tornado potential as SRH will be
high at that time. As heating occurs during the day, boundary layer
mixing as well as veering and weakening winds at 850 mb may reduce
tornado risk. However, ample deep-layer shear and nearly
unidirectional wind profiles will favor both cells and fast-moving
clusters of storms producing damaging gusts and locally severe hail
throughout the day.
...Northeast...
Within a broader area of cyclonic flow aloft, a leading shortwave
trough will move from the Lower Great Lakes into the Northeast, with
a 90 kt midlevel speed max and cooling aloft moving across NY and
parts of New England during the day. Low pressure will develop into
southern Quebec, with a cold front extending southward into the
region.
Surface heating and gusty south winds will bring 60s F dewpoints
into the area with up to 1000 J/kg MUCAPE expected. Relatively warm
profiles will develop near 300 mb, somewhat limiting storm depth.
However, ample midlevel cooling will still support sufficient
destabilization. Strong deep-layer shear and backed surface winds
ahead of the cold front will favor low-topped supercells. Cells
should develop over northern NY by 18Z, and will move quickly east,
producing marginal hail and sporadic damaging gusts initially. The
low EL height may mitigate hail production somewhat. By late
afternoon, a tornado or two will be possible as storms encounter a
stronger SRH environment farther east.
...Parts of MS/AL/GA/FL...
Wind fields associated with the remnants of Arthur will increase
from LA into GA today, as a weak surface low and midlevel wave move
across MS/AL/GA. This system will provide a focus for storms which
will spread northeast out of LA/MS into AL, the FL Panhandle, and
eventually into GA. Although temperatures aloft are warm, areas of
strong low-level shear and mid 70s F dewpoints will support
organized bands of storms, some with embedded stronger cells.
Transient supercells will be possible with localized tornado risk.
Storms are likely to be ongoing over southeast LA and southern MS at
the start of the period, and these will develop northeastward
throughout the day.
...OK into northwest TX...
An east-west oriented cold front will move southward across the TX
Panhandle, Oklahoma and northwest today, pushing well south of the
stronger westerlies aloft over the central Plains. The air mass
ahead of the front will feature 70s F dewpoints, while daytime
heating brings MUCAPE values into the 3000-4000 J/kg range. South of
this cold front, low pressure is forecast to develop over western TX
where the strongest heating will occur.
Isolated morning thunderstorms may be present from the KS/OK border
area eastward toward the Ozarks, and marginal hail cannot be ruled
out due to substantial elevated CAPE. Any storms that form near the
boundary as it moves south during the day may produce locally strong
gusts. The greatest risk of locally severe gusts or marginal hail
appears to be across southwest OK into northwest TX, where the front
will be more favorably timed with peak heating. Shear will be weak,
but extensive outflow is possible.
..Jewell/Weinman.. 06/18/2026
Read more
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 AM CDT Thu Jun 18 2026
Valid 191200Z - 201200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE UPPER MIDWEST...AND FROM NORTH TEXAS THROUGH THE SOUTHEAST...
...SUMMARY...
Isolated strong storms may produce gusty winds and hail across the
Upper Midwest. Additional strong thunderstorms may produce damaging
wind gusts from north Texas/southern Oklahoma through portions of
the Gulf Coast states and into the coastal Carolinas.
...Minnesota/Wisconsin...
An upper shortwave trough will migrate across the Upper Midwest on
Friday. This will bring a belt of enhanced northwesterly flow aloft
across the region. In the wake of a prior frontal passage,
boundary-layer moisture will be very modest (generally 50s F
dewpoints), but cool temperatures aloft and midlevel lapse rates
near 7 C/km will support weak destabilization (around 500-1000 J/kg
MLCAPE). Forecast soundings show vertically veering wind profiles
and elongated/straight hodographs with around 35-40 kt effective
shear magnitudes. Isolated higher-based supercells will be possible.
Steepened low-level lapse rates and the relatively dry
boundary-layer will support isolated strong gusts. Isolated
marginally severe hail also will be possible.
...ArkLaTex vicinity through the Gulf Coast states...
Most forecast guidance depicts an ongoing MCS across North Texas or
far southern OK at Friday morning. Strong gusts will be possible
with this system through the morning given modestly enhanced
mid/upper flow and a corridor of strong instability across the
ArkLaTex vicinity. This MCS and/or remnant MCV may continue
east/southeast across east TX or toward the lower MS Valley through
the day, tracking along a southward-sagging surface boundary.
Further east across the Gulf Coast vicinity, a very moist airmass
will be in place, with PW values near 2 inches common. This will aid
in moderate destabilization ahead of a west to east oriented surface
boundary. Vertical shear will be weak, but water laden downdrafts
could support isolated microbursts. It is unclear if convection will
be able to organize along the surface boundary into a forward
propagating cluster, but if this occurs, damaging wind potential
would increase.
...Coastal Carolinas...
A mid/upper shortwave trough will move across the area through
afternoon. Some guidance depicts a small MCS or cluster associated
with a strong low-level jet during the morning. As this feature
spreads northeast along the coast through afternoon, strong gusts
will be possible.
...Florida...
A seasonally moist and unstable airmass will reside across
north/central FL on Friday. Parts of the state will be on the
southern fringes of stronger mid-level flow associated with the
upper shortwave trough moving across the Carolinas. Some forecast
soundings show 20-30 kt midlevel low, and this may be sufficient for
transient organized cells along parts of the east coast. Additional
storms will be possible across the Panhandle and northern FL as
convection develops southward across the area ahead of a
southward-sagging surface boundary. Ample moisture/high PW values
and moderate instability will support occasional strong gusts with
the strongest storms.
..Leitman.. 06/18/2026
Read more
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0119 AM CDT Thu Jun 18 2026
Valid 201200Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL PLAINS...
...SUMMARY...
Severe thunderstorms are possible across portions of the central
Plains vicinity from Saturday afternoon into Saturday evening.
...Central Plains...
An upper ridge will initially be centered over the High Plains on
Saturday. An upper shortwave trough over the eastern Great Basin
will develop eastward, emerging over the central Rockies and
adjacent High Plains by 00z, and breaking down upper ridging. As
this occurs, mid/upper level flow will increase and a lee low will
deepen in the vicinity of eastern CO. A surface trough/dryline will
extend southward near the CO/KS border and along the NM/TX border.
Increasing south/southeasterly low-level flow will transport rich
boundary layer moisture (mid/upper 60s F dewpoints) northward across
KS, with low to mid 60s F dewpoints possible across much of NE.
Steep midlevel lapse rates atop the moistening boundary layer will
result in a moderate destabilization (MLCAPE 1500-2500 J/kg) across
the central High Plains and portions of central/eastern NE/KS.
Isolated to scattered thunderstorms are expected to develop within
upslope flow along the surface trough from far southeast WY into
eastern CO. As storms develop east/southeast with time, an
increasing southerly low-level jet may foster upscale development
into one or more bowing segments. Overall, supercell wind profiles
suggest large hail and perhaps tornadoes will be possible. If storms
grow upscale, damaging wind potential will increase during the
evening.
..Leitman.. 06/18/2026
Read more
Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0203 AM CDT Thu Jun 18 2026
Valid 211200Z - 261200Z
...DISCUSSION...
...Day 4/Sunday - Mid-MS Valley vicinity...
A weak mid/upper shortwave trough over the Mid-MO Valley Sunday
morning across the Mid-MS and lower OH Valley regions through the
period. A surface low over the central Plains will spread east in
tandem with the upper system, though the latitude at which this
occurs is uncertain. Furthermore, an ongoing MCS could be located
somewhere across eastern NE/KS and the adjacent MO Valley Sunday
morning. How this convection evolves through the day is also
uncertain. Nevertheless, rich boundary layer moisture will be in
place across the Lower MO/Mid-MS Valley, with moderate to strong
destabilization likely to the south of a surface boundary oriented
northwest to southeast across portions of the Mid-MS/Lower OH
Valleys. Some where risk appears likely, either from reinvigorated
morning convection, or from new storm development along outflow.
Given uncertainty into placement of key features, will hold off on
introducing 15 percent probabilities at this time, but areas will
likely be needed in subsequent outlooks.
...Days 5-8/Monday-Thursday - Plains to the Midwest and Southeast...
Modest west to northwesterly flow aloft will persist east of the
Rockies through much of the forecast period. Organized severe
potential is uncertain due to a lack of notable large scale forcing.
While some severe risk is likely each day, this risk will be driven
by mesoscale processes and convective evolution each day. Overall
predictability is low through most of next week.
Read more
