RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0109 AM CDT Thu Apr 16 2026
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS PARTS OF WESTERN AND CENTRAL NEW YORK INTO SOUTHERN
VERMONT...
CORRECTED FOR TYPOS AND WORDING
...SUMMARY...
A few severe thunderstorms are possible this afternoon in a corridor
across western through central New York (state) and adjacent
southern Vermont.
...Discussion...
A significant mid-level trough and embedded low now digging across
the Pacific Northwest is forecast to split as it continues inland
through this period. One perturbation, perhaps including a
continuing cyclonic circulation, is forecast to turn eastward across
the northern Rockies through the central Canadian/U.S. border area.
Another perturbation is forecast to dig southeastward across the
Great Basin into early Friday. It appears that the larger-scale
evolving troughing will be preceded by a significant cold frontal
surge to the lee of the northern U.S. Rockies, through much of the
northern and central Great Plains by 12Z Friday.
Downstream, initially prominent mid-level ridging centered near the
southern Atlantic Seaboard is forecast to become increasingly
suppressed, as one short wave trough, approaching southwestern
portions of the Great Lakes region early today, turns eastward then
southeastward across the lower Great Lakes vicinity into northern
Mid Atlantic. It appears that this will be trailed by another
perturbation, which is forecast to progress east of the Ozark
Plateau through the lower Ohio and Tennessee Valleys, before digging
across the southern Appalachians, downstream of short wave ridging
building across and east of the mid/upper Mississippi Valley.
...Mid South into lower Great Lakes and Northeast...
The primary and trailing short wave troughs advancing to the east of
the Mississippi Valley are forecast to be preceded by the remnants
of overnight convection across parts of the lower Great Lakes, Ohio
Valley, and Mid South at the outset of the period. The impacts of
associated cloud cover and outflow on destabilization within the
warm sector of a broad, but weak, surface low migrating northeast of
the lower Great Lakes during the day remain unclear. However,
various model output, including convection allowing guidance,
suggest that destabilization and strengthening shear along a warm
frontal zone (as it strengthens with differential heating) may
become a focus for organized strong thunderstorm development across
New York state by afternoon. It appears that this may include an
evolving cluster, perhaps preceded by more discrete thunderstorm
activity, in an environment conducive to evolving supercell
structures, with potential to produce severe hail, wind and a risk
for a couple of tornadoes.
Additional thunderstorm activity may eventually develop and
strengthen, accompanied by at least a risk for strong to severe wind
gusts by late afternoon, in a corridor of stronger daytime heating
ahead of a developing cold front spreading into the upper Ohio
Valley/Allegheny and Cumberland Plateau.
Farther west/southwest, there is not a well-defined signal in the
latest model output, but a corridor of differential surface heating
along weakening trailing convective outflow across the Mid South
vicinity could become a focus for supercell development. It
currently appears that this potential could peak across north
central into northeastern Arkansas by late this afternoon, aided by
moderate boundary-layer destabilization and stronger mid-level
forcing for ascent associated with a cyclonic vorticity center
migrating across the region.
...Southern Great Plains...
Moderate to strong potential instability is forecast to develop
beneath steep lapse rates, along and east of a dryline which likely
will be retreating westward across the high plains by early this
evening. While this will be conditionally supportive of severe
thunderstorm development, forcing to support initiation of sustained
thunderstorms remains unclear, aside from, perhaps, the higher
terrain near/east of the Texas Big Bend. Beneath moderate to strong
southwesterly mid/upper flow, this could include an isolated
supercell or two which could propagate across the Rio Grande River,
before weakening in the presence of increasing inhibition this
evening.
..Kerr/Lyons.. 04/16/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Thu Apr 16 2026
Valid 171200Z - 181200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF OKLAHOMA...KANSAS...MISSOURI...IOWA...ILLINOIS...FAR SOUTHEAST
MINNESOTA...AND WISCONSIN...
...SUMMARY...
Widespread severe thunderstorms are expected from parts of the
southern Plains to the Middle and Upper Mississippi Valley vicinity
Friday into Friday night. Tornadoes, possibly strong, very large
hail, and swaths of damaging winds will be possible.
...Southern Plains to Upper Midwest...
A potent upper trough from is expected to eject over the Plains and
Upper Midwest on Friday. Strong deep-layer southwesterly flow will
overspread the region early in the forecast period, with 850-700 mb
flow around 40-50 kt common from parts of OK/KS into WI. At the
surface, forecast guidance has trended a bit further north with the
position of a surface low Friday morning. This low is expected to be
located along the MO River near the SD/IA/NE border, and will
develop northeast into northern WI/MI U.P. by late afternoon. A
trailing cold front will push southeast across Upper MS/Mid-MO
Valley as this occur, becoming oriented from central MI to northwest
MO and southeast KS by 00z. Meanwhile, a second low is forecast to
develop over the TX Panhandle/western OK within strong heating near
a dryline extending southwest from western OK into
west-central/western TX. Ahead of these surface features, a
seasonally moist airmass will be in place, or, in the case of the
Upper Midwest, rapidly advect northward during the morning hours.
A plume of steep midlevel lapse rates, supported by cool to cold
temperatures aloft (near -16 C at 500 MB across portions of IA/MN/WI
at 21z, and -14 to -12 C further southwest) will overspread the
moist boundary layer. This will result in strong destabilization,
with MLCAPE around 2500-3500 J/kg expected across the warm sector.
This kinematic and thermodynamic environment will support robust
convective development near the Upper Midwest surface low
southwestward along the cold front into KS by midday. Initial
supercells are possible, especially closer to the surface low in the
Upper Midwest, and near the triple point/dryline in northwest
OK/south-central KS. More rapid upscale growth into a robust
line/LEWP is expected along the cold front from parts of IA into MO
and eastern KS. Given robust instability and very steep lapse rates,
significant damaging wind swaths will be possible. Additionally,
large to very large hail will be possible with any discrete
supercells, and possibly within line-embedded supercells. Low-level
wind profiles will also support a aerially extensive tornado risk,
both with QLCS mesovortex circulations, and with discrete
supercells. A corridor of perhaps greater tornado risk/coverage may
develop near the surface low from northeast IA into central WI.
Low-level SRH will be maximized in this area and forecast soundings
indicate large, curved hodographs becoming elongated above 2-3 km.
Furthermore, mixing ratios near 14 g/kg and very steep lapse rates
should support robust updrafts with low cloud bases. This are may
become a focused corridor for stronger tornadoes.
Linear convection should continue east across the MS River and Lake
Michigan during the evening and overnight hours, with a gradually
waning severe risk into portions of central/southern IL, Lower MI
and IN. Additional convection may develop during the evening and/or
overnight across parts of TX near the dryline, though this scenario
is more conditional. If storms do develop, large will be the main
risk.
..Leitman.. 04/16/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0205 AM CDT Thu Apr 16 2026
Valid 181200Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE OHIO VALLEY...
...SUMMARY...
Isolated strong to severe thunderstorms capable of damaging winds
and hail will be possible on Saturday across part of the Ohio
Valley.
...Ohio Valley...
A large-scale upper trough oriented over the Upper Midwest and
Plains will shift east over the Great Lakes, Midwest and TN Valley
on Saturday/Saturday night. Strong deep-layer southwesterly flow
will overspread the Ohio Valley ahead of an eastward-advancing cold
front. This front should be located from Lower MI into southeast MO
Saturday morning, moving across the Ohio Valley through early
evening. Modest boundary-layer moisture will be in place ahead of
the front. Daytime heating into the 70s and modestly steep midlevel
lapse rates will support weak destabilization (generally less than
1000 J/kg MLCAPE). While instability will be modest, strong low and
midlevel flow will support organized cells and/or line segments
capable of strong gusts. Any discrete cellular activity also may
produce marginally severe hail. These severe risk should gradually
wane during the evening with eastward extent.
...TX to the Lower MS Valley...
Thunderstorms are expected along a southeast-advancing cold front
Saturday afternoon and evening. Deep-layer flow will be oriented
parallel to the front, and convection may largely be anafrontal or
quickly undercut by the front. While weak MUCAPE is noted in
forecast soundings, severe potential is not expected at this time.
..Leitman.. 04/16/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CDT Thu Apr 16 2026
Valid 191200Z - 241200Z
...DISCUSSION...
Severe thunderstorm potential will be low through at least Day
6/Tuesday. In the wake of a cold front moving offshore the Atlantic
coast and into the Gulf, strong surface high pressure will build
east of the Rockies and persist across parts of the South and East
through Day 6/Tuesday. As a result, a dry and stable boundary layer
will preclude severe thunderstorm potential.
By the middle of the week, and upper trough is forecast to
overspread the western U.S. As this occurs, lee surface troughing
will allow for increasing southerly winds over the Plains, and Gulf
moisture will begin to return northward Days 7-8/Wed-Thu. It remains
uncertain if the upper trough will begin to eject eastward toward
the Plains at the end of the period. If this occurs, some severe
potential may develop across the Plains, though predictability is
low.
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