ACUS02 KWNS 240459
SWODY2
SPC AC 240457

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1157 PM CDT Wed Jul 23 2025

Valid 251200Z - 261200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY INTO
FRIDAY NIGHT ACROSS PARTS OF NEW ENGLAND INTO THE NORTHERN MID
ATLANTIC AND ACROSS NORTH DAKOTA AND ADJACENT PORTIONS OF THE GREAT PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorms, and perhaps a developing
line, may pose a risk of damaging wind gusts across parts of New
England and the northern Mid Atlantic on Friday.  The development of
an organized cluster of storms with potential to produce strong to
severe wind gusts is also possible across North Dakota by Friday evening.

...Discussion...
Models continue to indicate that fairly significant troughing within
the westerlies will dig across Quebec, northern New England and the
Canadian Maritimes during 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.  Across much of the Great Plains, Mississippi Valley,
and Great Lakes into middle and southern Atlantic Seaboard,
mid/upper heights are likely to remain generally high.  However, it
still appears that a subtle perturbation progressing across and east
of the northern Rockies could suppress mid-level heights across
North Dakota and adjacent portions of the northern Great Plains late
Friday through Friday night.

Latest model output appears increasingly suggestive that a notable
MCV may evolve within the weak flow across the central Great Plains
by early Friday, before migrating slowly northeastward, with a
number of weaker convectively generated or enhanced perturbations
downstream, across parts of the lower Missouri Valley into southern
Great Lakes/Ohio Valley.  But, this remains much more uncertain at
the present time.

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

...New England into northern Mid Atlantic...
Latest model output is not much clearer concerning potential storm
coverage and the risk of severe weather for Friday.  How far south
the cold front advances into New England before the boundary-layer
is able to destabilize appreciably also remains unclear.  However,
the front across New England, and the pre-frontal trough across the
northern Mid Atlantic, probably will become the focus of at least
scattered thunderstorm development, aided by forcing associated with
the digging mid-level trough.

Lower/mid-tropospheric lapse rates may not become particularly
steep, but seasonably high boundary-layer moisture content advecting
ahead of the cold front may still contribute to moderate mixed-layer
CAPE with daytime heating.  In the presence of 20-40+ 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 upscale growing southeastward
propagating clusters or a developing line accompanied by potentially
damaging wind gusts.

Due to lingering uncertainties, severe probabilities are being
maintained at 5 percent, but it is still possible that severe
probabilities could be increased in later outlooks for this period.

...North Dakota...
The NAM, in particular, continues to generate a notable convective
perturbation across North Dakota, mainly late Friday into Friday
night.  This is supported by other model output to an extent, and is
generally focused where lower/mid-tropospheric warm advection might
become maximized by Friday evening, on the leading edge of a
northward advecting plume of warm and increasingly capping air
around the 700 mb level.  Beneath steep lower/mid-tropospheric lapse
rates, it appears that low-level moistening will contribute to
moderate large CAPE supportive of vigorous convection, with
thermodynamic profiles conducive to downbursts and a strengthening
cold pool as forcing for ascent contributes to consolidating convection.

...Remainder of Great Plains into Ohio Valley...
Beneath the mid-level ridging, destabilization across the high
plains, and along the remnant front across the central Great Plains
through Ohio Valley, may become supportive of widely scattered
vigorous thunderstorm development.  Due to generally warm mid/upper
thermodynamic profiles and weak flow/shear, localized damaging wind
gust appears the primary potentially severe hazard.  It is not yet
clear that the coverage of any such activity will become sufficient
to support introduction of 5 percent severe probabilities.

..Kerr.. 07/24/2025

$$
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