Mesoscale Discussion 1153
NWS Storm Prediction Center Norman OK
0916 AM CDT Tue Jun 16 2026

Areas affected...southeastern Louisiana...southern
Mississippi...southern Alabama...Florida Panhandle

Concerning...Severe potential...Watch possible 

Valid 161416Z - 161615Z

Probability of Watch Issuance...40 percent

SUMMARY...Marginal risk for a few transient supercell structures
through the morning/afternoon.

DISCUSSION...Within the broader widespread thunderstorm activity
across the Gulf states, a few cells have exhibited transient
supercell characteristics in the last hour. Across this region,
tropical moisture is streaming northward from a disturbance across
far southern Texas. Strengthening 700-850 mb flow across the Gulf
coast amid this tropical air mass will support occasional stronger
cells with transient supercell characteristics. These will have the
potential to produce isolated damaging winds and perhaps a tornado.
Due to the limited coverage and transient nature of this potential,
a watch is unlikely to be needed but this area will be monitored for
changes through the afternoon.

..Thornton/Hart.. 06/16/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...TAE...BMX...MOB...JAN...LIX...LCH...

LAT...LON   30729111 30079177 29169172 28728940 28968859 29418881
            29838905 30218895 30278720 30458617 30398519 31088515
            31668520 31888744 31628753 30729111 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH

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