RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 AM CDT Tue Jun 16 2026
Valid 161300Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST...
...SUMMARY...
Severe thunderstorms are possible today and tonight across multiple
parts of the Midwest, as well as on a more isolated basis across the
Gulf Coast, south-central Plains and northern Plains.
...Midwest/Great Lakes...
A low amplitude shortwave trough will amplify and spread
east-southeastward over the Great Lakes today. While overall
moisture content will remain modest, steady low-level moistening is
expected ahead of a surface low/cold front, and south of a
north/northeastward-shifting warm front. This moistening and
insolation beneath a developing mid-level dry slot should support a
corridor of modest destabilization as the mid-level cold pool
(including 500 mb temperatures around -18 to -20C) overspreads the
region this afternoon. This environment should become sufficient for
a developing broken band of strong/severe low-topped storms
including supercells, posing a risk for severe hail/damaging winds
and possibly a couple of tornadoes from mid-afternoon through early
evening.
...Iowa/Upper Midwest late tonight...
A categorical Slight Risk has been introduced for what should be a
steadily increasing late-night/pre-dawn potential for large hail, at
least on isolated basis. This potential should tend to focus across
parts of central/eastern Iowa. Exact details of timing/spatial
extent of cap erosion are a bit uncertain, but will defer to a
significantly strengthening southwesterly low-level jet and
east/southeastward-advecting elevated mixed layer and ample
source-region elevated buoyancy regarding concern for large hail.
This will be as robust warm/moist advection develops and initial
height falls arrive into the region early Wednesday with increasing
elevated convection probable.
...South-central Plains...
Near/ahead of the stalling front, boundary-layer moistening may
support CAPE on the order of 1000-2000 J/kg across parts of southern
Kansas into southwestern Missouri, where mid-level inhibition may
remain weak enough through late afternoon/early evening to allow for
isolated/widely scattered thunderstorm development. Sufficient
vertical shear could support supercell development. Additional
severe storm development, at least on an isolated basis, is
plausible farther west-southwest later in the afternoon/early
evening across northern Oklahoma/southern Kansas into the Texas
Panhandle.
...Northern Great Plains into Midwest...
Models suggest that a corridor of fairly deep boundary-layer mixing
will precede the vigorous short wave trough digging across and
east-southeast of the Canadian/northern U.S. Rockies. Associated
mid-level forcing for ascent will contribute to sufficient
destabilization to support scattered thunderstorm development with
potential to produce some hail and scattered strong to severe
surface gusts late this afternoon into evening.
...Delmarva/coastal Mid-Atlantic...
Some strong/locally severe thunderstorms could occur tonight as
convection develop near/north of a near-coastal/offshore surface low
and northward-advancing warm front. Storms will tend to be elevated
inland, but modest buoyancy and strong unidirectional shear through
the cloud-bearing layer could yield some hail and/or gusty winds.
...Gulf Coast...
Strengthening westerly flow, including 20-40 kt in the 850-500 mb
layer, is anticipated regionally coincident with a moist boundary
layer. As diurnal heating/destabilization occurs, this may support
modestly organizing convection, perhaps transient supercell
structures, posing a risk for damaging wind gusts and perhaps a
brief tornado or two.
..Guyer/Broyles.. 06/16/2026
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