SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sat Jul 12 2025
Valid 122000Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
LOWER/MIDDLE OHIO VALLEY...
...SUMMARY...
Scattered severe storms capable of damaging winds are possible
across parts of the Lower/Middle Ohio Valley through sunset.
...20Z Update...
The primary change to the ongoing forecast was to remove severe
probabilities from lower Michigan where the airmass has become more
stable behind the surface front. Elsewhere, minor changes were made
base on current observations. Please see the previous forecast for
additional details.
..Wendt.. 07/12/2025
.PREV DISCUSSION... /ISSUED 1123 AM CDT Sat Jul 12 2025/
...Lower MI into Lower/Mid OH Valley...
Recent surface analysis shows a pre-frontal wind shift from central
Lower MI southwestward through central IN. The cold front itself is
a bit farther west, extending across western Lower MI through far
northwest IN and southern IL, although the temperature gradient is a
bit diffuse. Additionally, satellite imagery shows a series of
gravity waves ahead of the pre-frontal wind shift. These waves have
aided in the development of thunderstorms over northern Lower MI and
farther south in south-central MI. This complex pattern coupled with
cloudiness results in uncertainty regarding the overall convective
evolution across the region today.
The highest severe thunderstorm potential still appears to be across
north-central/northeast Lower MI, where recent mesoanalysis places a
belt of stronger low-level flow. This is verified by the APX VAD,
which has recently sampled 30 to 40 kt between 1 and 2 km. Upper 60s
to low 70s dewpoints are in place over the region, and mesoanalysis
already estimates minimal convective inhibition with MLCAPE from
1000 to 1500 J/kg. Some filtered heating is ongoing as well, with
instability expected to increase through the early afternoon ahead
of the approaching front. As mentioned in recently issued MCD #1654,
there may be a window of opportunity early afternoon this for
supercell development along/ahead of the front, especially across
northeast lower MI. Any such development would pose a threat of
damaging wind, isolated hail, and possibly a tornado. Otherwise,
multicell clusters and perhaps a transient supercell or two will
become increasingly possible into this afternoon, with a primary
threat of damaging wind.
Farther south, lift along the front combined with mesoscale ascent
attendant to the convective cluster currently over far southeast MO
should result in afternoon thunderstorm development from southern
IL/far western KY into much of IN. Strong buoyancy is expected ahead
of the front, but shear will be weaker, with a less organized storm
mode anticipated. Even so, given the number of storms anticipated, a
few convective clusters capable of damaging gusts are possible. This
risk should shift eastward into OH and KY before storm weaken this
evening.
...Southern Plains into the Ozarks...
A triplet of MCVs is apparent in recent satellite imagery, with one
MCV over southwest KS, another over the far eastern TX Panhandle,
and the last over the TX South Plains. Thunderstorm development is
possible with each of these features, particularly the one moving
eastward out of the eastern TX Panhandle into western/central OK.
Storms will likely diurnally increase and intensify this afternoon
across much of OK and a large part of north TX. Shear will be weak
across much of the region, except near the MCV where some
low/mid-level flow enhancement is possible. This could result in a
few more organized updrafts across north-central/central OK. Even
so, deep-layer flow will remain modest, which is expected to limit
the overall severe coverage.
...Colorado/New Mexico...
Thunderstorm development is again anticipated over the higher
terrain of central CO and north-central NM this afternoon. Modestly
enhanced mid/upper-level north-northwesterlies should aid in
weak/transient updraft rotation, supporting the potential for
isolated severe hail. The airmass across the CO Plains is not
expected to be as favorable for storm persistence as the last few
days, suggesting the threat for strong gusts is lower. The airmass
is a bit more favorable across NM, suggesting a relatively greater
chance of a few severe across the NM High Plains.
...WI into Upper MI...
Isolated severe hail/damaging winds may also develop along the
secondary cold front advancing eastward across northern/eastern
WI and Upper MI. Cooling mid-level temperatures will aid in weak
MLCAPE of 500-1000 J/kg this afternoon. Westerly low-level wind
profiles will modulate the degree of deep-layer shear, helping to
marginalize the overall threat.
...Mid-South/Tennessee Valley to the Carolinas/Virginia...
A pulse storm environment characterized by weak effective bulk shear
but moderate buoyancy will support a threat for isolated wet
microbursts from mid-afternoon to early evening, with tree damage
possible.
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