RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Fri Jun 12 2026
Valid 122000Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEAST...MID-ATLANTIC...AND SOUTHERN APPALACHIANS AS WELL AS
PARTS OF THE SOUTHERN HIGH PLAINS...
...SUMMARY...
Strong to severe storms capable of damaging winds are expected
across parts of the Appalachians, Mid-Atlantic, and Northeast,
mainly this afternoon and evening. Severe storms with a threat of
large hail and severe wind gusts will also be possible across parts
of the south-central High Plains.
...20z Update...
The previous forecast remains on track with minimal changes required
to the existing probability lines based on ongoing convective trends
and recent model guidance. The primary outlook amendment was the
introduction of 5% hail probabilities across portions of eastern
Nebraska.
...Nebraska...
12z ensemble guidance hinted at thunderstorm development across
eastern NE during the 09-12 UTC period as a weak low-level cold
front impinges on a plume of northward returning moisture. More
recent runs of the RAP/RRFS/HRRR continue to show this potential and
depict a fairly robust thermodynamic environment featuring MUCAPE
values upwards of 4000 J/kg. 18 UTC RAOBS from the southern High
Plains and Rockies sampled steep mid-level lapse rates that will
advect eastward over the next 18 hours, and recent model solutions
appear to be capturing surface moisture return well. These trends
lend sufficient confidence to introduce a targeted hail risk area.
...Mississippi/Alabama...
5% wind probabilities were removed across northern MS/AL based on
recent radar trends, which depict the outflow boundary of a decaying
MCS rapidly progressing south and undercutting developing
convection. Strong buoyancy immediately downstream may support some
localized damaging wind threat through the afternoon, but latest
model guidance largely shows diminishing convective activity as the
outflow surges south.
..Moore.. 06/12/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Jun 12 2026/
...Mid-Atlantic into New England this afternoon/evening...
Within the northern stream, a shortwave trough will progress
east-northeastward over the lower Great Lakes this
afternoon/evening, while an associated surface cold front moves
eastward into New England and southeastward into the Mid-Atlantic.
Forcing for ascent will not be particularly strong and the stronger
midlevel flow/deep-layer vertical shear will remain displaced to the
cool side of the front. Still, 25-30 kt midlevel flow will overlap
the warm sector this afternoon from northern Chesapeake Bay
northward into eastern NY. Strong surface heating is ongoing from
the Piedmont into VA/southern PA, with a few more cloud patches from
northeast PA into central NY. The net result will be moderate
buoyancy (MLCAPE of 1000-2000 J/kg) in an environment with steep
low-level lapse rates and weak upper flow, favoring multicell
clusters with occasional wind damage. The weak forcing for ascent
suggests that widely scattered, loosely organized clusters will be
possible this afternoon, with some gaps in the wind threat.
...Southern High Plains late this afternoon into early tonight...
Lee cyclogenesis across southeast CO will draw low-level moisture
northwestward into the southern High Plains as a stalled front
begins to lift northward across the TX Panhandle. Thunderstorm
development is expected this afternoon/evening with upslope flow
into the higher terrain of NM, and along the Raton Mesa. Deep-layer
vertical shear/hodograph length will be sufficient for supercells
initially off Raton Mesa, with large hail the primary threat. Some
upscale growth and an increase in the potential for severe outflow
gusts is expected late this evening as storms spread eastward toward
southwest KS and the northern Panhandles in association with a
nocturnal low-level jet and strengthened warm advection/moisture
transport.
...Eastern KS/western MO early Saturday...
In response to low-level warm advection and returning moisture,
elevated convection is probable late in the period across eastern
KS/western MO. This area will be near the east edge of the steep
midlevel lapse rates, where isolated large hail will be possible.
There will also be some potential for evolution into a cluster or
two with isolated damaging gusts. Farther north into eastern NE
(very near the end of the period) there will be a chance for
elevated storms with some hail. This area will be re-evaluated this
afternoon in the 20z update.
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 PM CDT Fri Jun 12 2026
Valid 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SUNDAY ACROSS MUCH
OF THE NORTHERN MID ATLANTIC COAST STATES...
...SUMMARY...
Severe thunderstorms are possible across the lower Great Lakes and
upper Ohio Valley vicinity through much of the northern Mid Atlantic
Sunday.
...Discussion...
Downstream of initially amplified mid-level ridging offshore of the
Pacific coast, models indicate that flow will continue to trend
cyclonic east of the Rockies through the Atlantic Seaboard, to the
south of a broadening vortex centered near southern Hudson Bay.
Within this regime, it appears that notable short wave troughing
will pivot east of the Upper Midwest through the southeastern
Canadian provinces and Northeast by late Sunday night, accompanied
by cyclogenesis across the lower Great Lakes through St. Lawrence
Valley vicinity. It appears that this may be preceded by the
remnants of an initially fairly notable mesoscale convective vortex,
within strengthening westerly flow across the Allegheny/Cumberland
Plateau through the northern Mid Atlantic by early Sunday evening.
...Northeast...
There remains considerable spread within the latest model output
concerning the extent of convective potential for this period.
Mostly this appears related pre-frontal low-level moisture return
and destabilization across the upper Ohio Valley into the lee of the
lower Great Lakes, which could be slowed or impeded by the influence
of preceding convective outflow. However, guidance generally
suggests that destabilization prior to the arrival of the MCV and
belt of enhanced lower/mid-tropospheric wind fields (30-40+ kt) will
be sufficient to support potential for organized severe convection
east of the Allegheny Mountains through the northern Mid Atlantic by
late Sunday afternoon. More substantive strengthening of mid-level
wind fields and forcing for ascent appear likely to overspread the
pre-frontal environment across parts of the upper Ohio Valley into
the lee of the lower Great Lakes region, where it appears increasing
model output is now suggesting that the evolving warm sector may
become sufficiently unstable to support a risk for organized severe
storm development.
Damaging wind gusts accompanying organizing lines and/or clusters
appear the primary severe hazard, but there also appears at least
some potential for a few tornadoes. It is still possible that
severe weather probabilities will need to be increased further in
later outlook updates for this period.
..Kerr.. 06/12/2026
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