Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Thu Jun 18 2026
Valid 182000Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
WESTERN NORTH TEXAS...THE SOUTHEAST AND CAROLINAS...INTO NEW
ENGLAND...
...SUMMARY...
Isolated to scattered severe thunderstorms remain likely from
Kentucky and the central Appalachians to the Mid-Atlantic, with
primarily damaging wind gusts or marginal hail. Scattered severe
storms are possible from upstate New York into New England, with
damaging wind gusts and tornado potential. A few tornadoes may also
occur over parts of the middle Gulf Coast and southeast states, and
scattered storms may produce damaging winds or marginal hail from
Oklahoma into western North Texas.
...20z Update TX/OK...
Forecast confidence has increased late this afternoon into tonight
that one or more semi-organized clusters of thunderstorms will
develop and spread southeastward across parts of western North TX
with a risk for damaging gusts. Strong convergence near an
anomalously deep surface low and sagging cold front will support
numerous thunderstorms tonight. Despite marginal deep-layer shear
for organization, a hot and very unstable air
mass in vicinity of the surface low will allow for strong cold pool
development, potentially supporting severe outflow gusts. More
isolated damaging gusts and/or marginally severe hail remain
possible farther north into OK. Have upgraded wind probabilities to
15% and a categorical Level 2 Slight Risk for portions of western
North TX.
...Southeast...
Convection associated with the remnants of Arthur will persist
through tonight along a stalled frontal zone in the Southeast. While
clustering has resulted in more linear structures, enhanced flow
aloft and pockets of stronger low-level shear near the front may
still support occasional rotating updrafts, with the risk for a
couple of tornadoes or damaging gusts from eastern AL, into GA and
the western Carolinas through tonight. Have reduced maximum tornado
probabilities, but will maintain a broad 5% for occasional supercell
structures along/near the front.
...New England...
The broken band of storms ahead of the cold front should continue
eastward and gradually weaken into this evening. Southern portions
of the line over MA, CT and RI may remain stronger given better
buoyancy, but storm coverage here should become more isolated with
time. Damaging gusts and perhaps a tornado or two remain possible.
Have trimmed probabilities behind the cold front where the risk has
decreased. No other changes were made, see the previous discussion
for more information.
..Lyons.. 06/18/2026
.PREV DISCUSSION... /ISSUED 1116 AM CDT Thu Jun 18 2026/
...NY/New England...
A fast-moving low-topped squall line is tracking eastward across NY.
Low and mid level wind fields in this region are very strong,
contributing to occasional bowing structures and QLCS mesocyclones.
This activity will spread into VT/NH through the afternoon with a
continued risk of damaging winds and isolated tornadoes. Confidence
in severe storms farther south into southern New England is lower,
but at least isolated strong/damaging wind gusts are possible.
...KY into Mid Atlantic...
A remnant outflow boundary from overnight storms extends across KY
into southern VA. Strong heating along and south of the boundary
will likely result in renewed convection this afternoon, in a zone
of moderate westerly flow aloft and CAPE values around 2000 J/kg. A
few severe storms are expected in this corridor, with activity
moving into northern NC later today. Damaging winds are the main
risk.
...Gulf Coast into Carolinas...
The remnant circulation of Arthur is becoming more progressive with
time, and is accelerating eastward. As this occurs, the zone of
relatively strong southerly low-level winds will also shift across
AL into GA and eventually SC/NC tonight. Ample low-level moisture
and high theta-e values will coincide with the region of strong
shear, and CAM solutions suggest clusters of thunderstorms in this
area as well. This suggests at least some risk of damaging wind
gusts and tornadoes through the afternoon and night as the system
moves northeastward.
...TX/OK...
Scattered thunderstorms will occasional hail risk will slowly
diminish across northern OK this afternoon. Later today, new
thunderstorms are expected to develop in a hot and very unstable air
mass in vicinity of the surface low near ABI/SJT. These slow-moving
storms will have some damaging wind and hail risk through the
evening.
Read more CHECK UPDATE ZOOM GRAPHIC
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