RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0243 PM CDT Mon Jun 15 2026
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN HIGH PLAINS AND FROM THE CENTRAL DAKOTAS TO CENTRAL
MINNESOTA...
...SUMMARY...
Isolated large hail and severe thunderstorm winds may occur across
the southern High Plains and Dakotas/Upper Midwest this afternoon
and evening.
...20z Update...
No appreciable forecast changes were required. Based on latest
analyses, the highest severe wind threat remains across the eastern
Dakotas/western Minnesota where low-level lapse rates have increased
to near dry adiabatic ahead of approaching convection attendant to a
low-level vorticity maximum. A few recent severe wind gusts have
accompanied some of this convection as it moves into the plume of
steep low-level lapse rates. However, based on latest guidance
thunderstorm coverage should remain widely scattered through early
evening, suggesting that 5% wind probabilities remain the most
appropriate characterization of the risk.
Across the southern High Plains, convective initiation is underway
within the southern Rockies. Per MRMS vertical ice trends, some
large hail may accompany some of this initial activity before it
spreads east through the evening. Based on latest model trends, a
convective cluster will likely materialize out of the scattered
thunderstorms north of the Albuquerque area and will pose a severe
wind threat downstream across east-central NM later this evening. As
with the northern Plains, this threat should be sufficiently
isolated to maintain only 5% wind probabilities. See the previous
discussion below and MCDs #1149 and #1150 for additional forecast
details.
..Moore.. 06/15/2026
.PREV DISCUSSION... /ISSUED 1111 AM CDT Mon Jun 15 2026/
...Southern High Plains...
Northwesterly flow aloft will support a sharpening lee trough across
the southern High Plains today, with lee cyclogenesis yielding a
surface low over southeast CO by the late afternoon. Mass response
to the deepening lee trough and developing surface low will result
in moist low-level southeasterly/southerly flow across much of the
southern High Plains. This moistening will help offset mixing via
diurnal heating, keeping dewpoints in the 50s through the afternoon.
Steep mid-level lapse rates will be in place as well, with the
combination of low-level moisture and steep mid-level lapse rates
supporting airmass destabilization and moderate buoyancy by this
afternoon.
Thunderstorm development is initially expected over the high terrain
of south-central CO and central NM during the afternoon. Moderate
deep-layer westerly flow will take these storms into the lower
elevations of the southern High Plains during the late afternoon and
evening. Moderate buoyancy combined with 30 to 40 kt of effective
shear will support the potential for a few supercells and sustained
multicells, with potential consolidation into small organizing
southeastward-moving clusters. Hail is possible early in the
convective cycle, with a trend towards more damaging gusts within
any forward-propagating clusters during the late afternoon and
evening.
...Dakotas/Minnesota...
Morning satellite imagery shows a well-defined shortwave trough
dropping southeastward into the northern Plains within the western
periphery of a broad upper trough that extends over much of the
central and eastern CONUS. Surface moisture will be limited ahead of
this wave, but low to mid-level moisture attendant to the shortwave
and cold temperatures aloft will still support modest buoyancy
across the region this afternoon. This buoyancy coupled with ascent
from the shortwave will result in isolated to widely scattered
high-based thunderstorms. Additionally, strengthening
west-northwesterly flow attendant to the shortwave could yield some
strong/locally severe wind gusts this afternoon through around
sunset.
...Gulf Coast/Coastal Southeast...
A very moist airmass is in place in the vicinity of a weak frontal
zone that extends from the TX Coast northeastward through the
central Gulf Coast and southern GA. Numerous to widespread showers
and thunderstorms are anticipated across much of this region. The
airmass is weakly sheared, favoring a slow-moving, disorganized
storm evolution with heavy rain as the primary risk (as noted in the
Day 1 WPC Excessive Rainfall Outlook). However, a few damaging gusts
from water-loaded downbursts are still possible. Overall coverage is
expected to remain less than 5%.
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Mon Jun 15 2026
Valid 171200Z - 181200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MID-MISSISSIPPI VALLEY INTO INDIANA AND WESTERN OHIO....
...SUMMARY...
An all-hazards severe thunderstorm event is expected across portions
of the Middle Mississippi Valley into Indiana on Wednesday. Intense
thunderstorms may produce swaths of damaging wind, as well as strong
tornadoes and very large hail.
...Synopsis...
A strong mid-level jet will extend from the Northwest to the Ohio
Valley. An embedded 75 to 85 knot mid-level shortwave trough will
extend from Nebraska into Iowa by Wednesday afternoon. A strong
surface cyclone will move from eastern South Dakota to southern
Ontario during the period.
...Midwest...
Elevated supercells will likely be ongoing at the beginning of the
period across central/eastern Iowa at the nose of the low-level jet.
This cluster will continue to move east-southeast along/north of the
warm front through the day. This activity will likely have some hail
threat through the day with at least some tornado threat on the
southern periphery if any storms can latch onto the warm front.
Strong lower tropospheric flow should result in rapid
recovery/destabilization in the wake of these morning storms across
central/northern Illinois. A very favorable kinematic environment
will be in place with 70 knots of mid-level flow and 100+ knots of
upper-level flow with a 60+ knot low-level jet. Therefore, any
storms which develop within this zone could have a threat for very
large hail, and strong tornadoes. Due to this morning convection,
there is considerable uncertainty exactly where this most favorable
environment may set up and how broad of a region it will be.
Notably, strong isentropic ascent is forecast along the frontal zone
through the entire period which could result in continued
development along the warm frontal zone (more widespread than
currently depicted by guidance) and a limited window for recovery in
the wake of the morning storms.
Despite these uncertainties, have upgraded severe probabilities to
45% in the region where multiple rounds of severe weather appear
most likely. Conceptually, the 12Z RRFS solution matches a
reasonable solution with a morning cluster of supercells including a
severe supercell on the southern extent. Additional supercells
developing along the trailing outflow/warm front during the
afternoon, followed by supercells developing along the cold front by
late afternoon. Even if storm development north of the warm front is
quite extensive during the day, forecast soundings show a Bunkers
storm motion parallel to the expected front/outflow orientation.
This points toward a favorable environment for one or more
supercells to move along the boundary in a favorable tornadic
environment.
Widespread storm development is expected along the cold front by
late afternoon from southeast Iowa to far eastern Kansas. Very
strong instability and moderate to strong shear will support
supercells capable of large to very large hail. In addition, strong
low-level shear will support the potential for strong tornadoes.
There is some question regarding storm mode along the front. Strong
forcing would favor more storm interaction and upscale growth, but
fast storm motions (40-50 knots) and a Bunkers RM motion nearly
perpendicular to the front may support maintenance of supercell mode
at least within some areas along the front. This would support a
greater tornado threat during the evening from north-central
Missouri to central Illinois. If storms do grow more upscale early
in the lifecycle, the tornado/hail threat would be reduced, but the
threat for significant wind gusts would increase substantially.
...Gulf Coast...
A Marginal Risk has been added along the Gulf as a tropical airmass
moves inland with a strengthening wind field associated with the
tropical disturbance identified by the NHC.
..Bentley.. 06/15/2026
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