ACUS03 KWNS 230726
SWODY3
SPC AC 230725

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0225 AM CDT Wed Jul 23 2025

Valid 251200Z - 261200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY INTO
FRIDAY NIGHT ACROSS MUCH OF MAINE...NEW
HAMPSHIRE...VERMONT...MASSACHUSSETTS...RHODE
ISLAND...CONNECTICUT...MUCH OF CENTRAL AND EASTERN NEW YORK...LONG
ISLAND...PARTS OF NORTHEASTERN PENNSYLVANIA...NORTHERN NEW
JERSEY...AND NORTH DAKOTA...ADJACENT PORTIONS OF EASTERN
MONTANA...NORTHERN SOUTH DAKOTA...AND WESTERN MINNESOTA...

...SUMMARY...
Scattered strong thunderstorms, and perhaps a developing line of
storms, may impact much of New England into parts of the northern
Mid Atlantic region Friday, accompanied by potentially damaging wind
gusts and perhaps some hail.  The development of an organized
cluster of storms with potential to produce strong to severe wind
gusts is also possible across parts of the northern Great Plains.

...Discussion...
Models indicate that fairly significant troughing within the
westerlies will dig across Quebec, northern New England and the
Canadian Maritimes through this period.  Weaker troughing is also
forecast to dig into portions of the British Columbia and Pacific
Northwest coast, as well as inland across California through the
Great Basin.  Downstream, a weak perturbation migrating across and
east of the northern Rockies may contribute to weak mid-level height
falls across the North Dakota vicinity late Friday into Friday
night.  Otherwise, models indicate that mid/upper heights will
remain generally high across much of the central and southern Great
Plains through the middle and southern Atlantic Seaboard.  I

In lower levels, a cold front is likely to advance across much of
the Northeast, while its trailing flank continues to stall and
weaken across the Ohio Valley through central and southern Great
Plains.

...New England into northern Mid Atlantic...
Lower/mid-tropospheric lapse rates may not become particularly
steep, but seasonably high boundary-layer moisture content advecting
ahead of the southward advancing cold front may still contribute to
moderate mixed-layer CAPE with daytime heating.  In the presence of
30-50 kt westerly flow in the 850-500 mb layer overspreading much of
the region, the environment may become conducive to organized
convection, perhaps including a couple of supercells, and an upscale
growing southeastward propagating cluster or line.

Strong to severe, potentially damaging, wind gusts, appears the
primary hazard, though mid-level cooling across parts of northern
New England might become conducive to severe hail.  It is still
possible that severe probabilities will need to be increased in
later outlooks for this period, particularly across parts of
northern New England, as lingering uncertainties perhaps become
better resolved.

...Northern Great Plains...
It appears that a plume of steep mid-level lapse rates may
overspread much of the northern Great Plains, as the subtle
mid-level perturbation emerges from the northern Rockies Friday.
Coupled with low-level moistening into the vicinity of the lee
surface troughing, this may contribute to moderate to large
potential instability by Friday afternoon.

Thunderstorms may initiate in the form of high based convective
development across eastern Montana into the western Dakotas during
the late afternoon, before spreading into this environment and
perhaps intensifying/growing upscale in the presence of
strengthening lower/mid-tropospheric warm advection.  Although shear
may be rather modest to weak, the evolution of an organizing cluster
with potential to produce strong to severe wind gusts might not be
out of the question, based on the notable convective signal evident
in the 23/00Z NAM, in particular.

..Kerr.. 07/23/2025

$$