Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Thu Jun 19 2025
Valid 192000Z - 201200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE
NORTHEAST AND MID ATLANTIC STATES...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
DAKOTAS AND THE UPPER MIDWEST...
...SUMMARY...
Severe thunderstorms are expected across much of the Mid-Atlantic
region through this evening, and to a lesser extent into the
Carolinas and over portions of New England. Severe/damaging wind
gusts are the primary concern. An isolated large hail and damaging
wind threat should also develop across parts of the northern
Plains/Upper Midwest, primarily during the evening/overnight hours.
...20z Update...
The prior outlook remains valid with only minimal changes. Across
parts of the Northeast and Mid Atlantic, several bands/clusters of
strong to severe storms are ongoing ahead of an upper trough over
the upper OH Valley. Moderate buoyancy and deep-layer shear will
continue to support storm organization into line segments and
clusters with an attendant risk for damaging gusts focused across
the Enhanced area. A few weak supercell structures were also noted
over eastern PA into southern New England, where some isolated hail
and a brief tornado will be possible. Convection should continue
into this evening before slowly weakening after sunset.
...Southeast...
In the wake of early morning remnant storms, an advancing outflow
has shifted south across MS/AL and eastern AR. The cluster of storms
on the surging outflow may occasionally produce damaging guts given
the moderate instability. Weak vertical shear should keep the threat
isolated. Have trimmed the MRGL and thunder behind this activity
where additional storms are not expected.
Otherwise, additional storms are possible across the Northern Plains
tonight. See the prior discussion for more info.
..Lyons.. 06/19/2025
.PREV DISCUSSION... /ISSUED 1115 AM CDT Thu Jun 19 2025/
...Eastern US...
A broad and low-amplitude shortwave trough is moving across the
Great Lakes region and Ohio Valley today. Ahead of the trough,
visible satellite imagery shows mostly clear skies from eastern NY
and much of New England southward across the Mid-Atlantic region and
Carolinas. Warm/moist conditions will develop by mid-afternoon,
yielding MLCAPE values of 2000-3000 J/kg across this broad area.
Scattered thunderstorms are expected to develop, with the highest
concentrations moving off the higher terrain of PA/VA/NC and
tracking eastward across the ENH risk area.
Forecast soundings along this corridor show 35-50 knot westerly flow
aloft, which will aid in thunderstorm organization and longevity.
Low-level winds are relatively weak/veered, and mid-level lapse
rates are marginal for intense updrafts. This suggests that
damaging wind gusts are the primary concern today.
...ND/MN/WI This Evening/Tonight...
A large upper ridge has become established across the Rockies and
High Plains, with the primary westerlies now extending from MT into
the Dakotas and Great Lakes. Several weak perturbations will top
the ridge today and tonight, and a strengthening low-level jet will
encourage the development of clusters of thunderstorms. One cluster
is expected this evening over parts of MN/WI, with a risk of large
hail.
There is increasing concern for a cluster of storms developing
across southern ND, which may persist through the night into
southern MN. While this scenario is only shown in a handful of 12z
models, have shifted the SLGT farther south for this conditional
risk.
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