982
ACUS03 KWNS 251923
SWODY3
SPC AC 251923

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0223 PM CDT Fri Jul 25 2025

Valid 271200Z - 281200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THE EASTERN
DAKOTAS INTO PORTIONS OF THE UPPER MISSISSIPPI RIVER VALLEY AND
ACROSS THE MID-ATLANTIC AND PORTIONS OF NEW ENGLAND...

...SUMMARY...
Severe thunderstorms are possible from the eastern Dakotas into the
Upper Mississippi Valley as well as across portions of the
Mid-Atlantic and New England region.

...Synopsis...
An upper ridge currently over the Southeast will gradually shift
west over the next 48-72 hours into the south-central U.S.
Strong/severe thunderstorm chances will largely be focused on the
north/northeastern periphery of the ridge as shortwave impulses
embedded within strong westerly mid-level flow overspread buoyant
air masses.

...Eastern Dakotas into the Upper MS Valley...
Forecast confidence remains low for Sunday across the eastern
Dakotas into portions of the upper MS Valley. A low-amplitude
mid-level wave is forecast to round the apex of the mid-level ridge
through the afternoon/evening across ND/MN. A residual MCS from
overnight Saturday may accompany this wave, though the intensity of
this MCS by Sunday morning remains uncertain. However, this will
have a direct impact on thunderstorm development/evolution Sunday
afternoon. Several deterministic solutions (most notably recent NAM
and ECMWF runs) suggest either a re-intensification of the MCS
and/or new convective development along an outflow boundary across
MN by late afternoon. Given forecast MLCAPE of 3000-4000 J/kg and
30-40 knots of deep-layer wind shear, this activity could strengthen
into a well-organized, severe MCS through the late evening hours as
it propagates southeastward along a warm frontal zone into parts of
IA and/or WI. Other solutions, including the high-res RRFS, depict a
weaker early-morning MCS and more limited thunderstorm coverage
through late evening. Ensemble guidance shows similarly dichotomous
solutions. Severe risk probabilities were maintained as-is given
then spread in solutions, but higher risk highlights will likely be
needed if guidance begins to coalesce around the NAM/ECMWF
solutions.

...Mid-Atlantic into parts of New England...
A weak surface trough/cold front is forecast to push eastward across
the Northeast/Mid-Atlantic region through peak heating. A moist air
mass will likely remain in place through the weekend and will
promote widespread MLCAPE values of at least 1000 J/kg along with
limited capping. West/northwesterly flow aloft coupled with modest
low-level winds should support adequate deep-layer wind shear for a
few strong/severe thunderstorms as convection develops by mid/late
afternoon.

..Moore.. 07/25/2025

$$