350
ACUS03 KWNS 170732
SWODY3
SPC AC 170731

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 AM CDT Tue Jun 17 2025

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NEW ENGLAND
INTO THE MID ATLANTIC...

...SUMMARY...
Strong to potentially severe thunderstorms are forecast on Thursday
from parts of New England into the Mid Atlantic and Carolinas.

...Synopsis...
A seasonably deep mid/upper-level trough is forecast to move across
parts of southeastern Canada and adjacent portions of the northeast
CONUS on Thursday. In conjunction with this trough, a surface
cyclone is expected to move from southeast Ontario into southern
Quebec, as a trailing cold front moves through parts of the
Northeast/New England and the Mid Atlantic.

To the west, an upper-level ridge will continue to build from the
southern Rockies into parts of the central Great Plains, with
multiple midlevel shortwave troughs expected to move from the Great
Basin into the northern Rockies and High Plains along the periphery
of the ridge.

...Parts of New England southward into the Mid Atlantic, Carolinas,
and Southeast...
Rich low-level moisture will already be in place across parts of the
Carolinas and Mid Atlantic Thursday morning, with some northward
moisture transport expected through the day along/ahead of the
approaching front. Guidance continues to vary somewhat regarding
timing of the front, and also the extent to which stronger
mid/upper-level flow lags behind the front. However, in general,
moderate destabilization is expected into at least southern New
England by afternoon, and perhaps farther north depending on
lingering cloudiness and frontal timing.

Scattered thunderstorm development will be possible along/ahead of
the front from the Carolinas/Mid Atlantic into New England during
the afternoon. Wind fields will generally be stronger with northward
extent. Depending on the extent of destabilization, supercells and
organized clusters will be possible across parts of New England and
perhaps the northern Mid Atlantic, which would pose some threat of
all severe hazards. Farther south into the southern Mid Atlantic and
Carolinas, deep-layer shear will be weaker, but favorable low-level
moisture, strong buoyancy, and modest midlevel southwesterlies will
support outflow-driven clusters capable of damaging winds and
possibly some hail.

The organized severe threat will tend to decrease with southwestward
extent, due to weaker deep-layer flow. However, favorable low-level
moisture and buoyancy could support a few strong to locally severe
storms along the trailing cold front into parts of the Southeast
during the late afternoon and evening.

...Parts of the Upper Great Lakes/Midwest...
In the wake of the departing mid/upper-level shortwave trough,
modest lingering low-level moisture beneath relatively cool
temperatures aloft may support moderate diurnal destabilization
across parts of the Upper Great Lakes and Midwest. Some guidance
develops southeastward-moving convection across parts of northeast
MN into northern WI during the afternoon, possibly in response to a
midlevel jetlet approaching the Upper Midwest from the northwest.
This scenario is uncertain, but moderate midlevel northwesterly flow
and sufficient deep-layer shear would support at least an isolated
severe threat if convection can be sustained during the afternoon
and evening. Other strong storms may develop Thursday night within a
warm-advection regime.

...Northern Plains...
Increasing low-level southerly flow will aid in low-level moisture
return across parts of the central/northern Plains on Thursday.
Strong diurnal heating will result in MLCAPE increasing above 2000
J/kg into parts of the Dakotas and Nebraska. Wind profiles will
support organized convection, and MLCINH may be mostly eroded by
late afternoon, though potential for storm development into evening
is highly uncertain, given the presence of rising midlevel heights
and generally limited large-scale ascent.

Later Thursday evening into the overnight, a nocturnal low-level jet
may aid in elevated storm development, though the details of any
severe threat associated with this potential late-period convection
remain uncertain at this time.

..Dean.. 06/17/2025

$$