SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0223 AM CDT Sun Jun 15 2025
Valid 171200Z - 181200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS AND LOWER TO MID MISSOURI VALLEY...
...SUMMARY...
Thunderstorms with an isolated large hail and wind-damage threat
will be possible on Tuesday across parts of the central Plains and
lower to mid Missouri Valley. Outside of this area, marginally
severe storms may develop over parts of the central U.S. An isolated
severe threat is also expected across parts of the Central
Appalachians and Mid-Atlantic.
...Great Plains/Lower to Mid Missouri Valley/Mid to Upper
Mississippi Valley...
At mid-levels, a shortwave trough is forecast to move into the
Rockies on Tuesday, as a ridge remains in place over the southern
Plains. At the surface, a cold front will advance southward through
the central U.S., likely reaching southern Kansas, northwest
Missouri and southeast Iowa by afternoon. To the south of the front,
surface dewpoints in the lower to mid 70s F will contribute to
moderate to strong instability across much of this moist airmass by
afternoon. As low-level convergence increases, convection is
expected to initiate along and near the front, with scattered strong
to severe thunderstorms moving southeastward toward the instability
axis in the late afternoon and early evening.
Model forecasts suggest that an impressive thermodynamic environment
will be in place ahead of the front by Tuesday afternoon. From 21Z
to 00Z, NAM forecast soundings along parts of the instability axis
have MLCAPE peaking between 4000 and 5000 J/kg. Moderate deep-layer
shear is also forecast, mostly due to speed shear in the mid-levels.
This environment should support supercells with large hail,
especially early in the event when storms are more likely be
discrete. A wind-damage threat is also expected to develop as storms
congeal, and as a line gradually organizes. The severe threat should
persist through much of the evening, with MCS development possible.
Further northwest into parts of the central High Plains, upslope
easterly flow is forecast within a post-frontal airmass. Surface
dewpoints will be mostly in the 50s F. As surface temperatures warm
during the day, pockets of moderate instability are expected to
develop over parts of the region. Thunderstorms are expected to
initiate in the higher terrain during the early to mid afternoon,
with storms moving eastward into the lower elevations. Steep
mid-level lapse rates and moderate deep-layer shear should be
sufficient for a marginal severe threat.
...Central Appalachians/Mid-Atlantic...
At mid-levels, a subtle shortwave trough is forecast to move
eastward across the southern and central Appalachians on Tuesday.
Ahead of this feature, a very moist airmass will be in place with
surface dewpoints in the lower to mid 70s F over much of the
Atlantic Coastal Plain. By afternoon, moderate instability is
expected to develop within most of this airmass. Convection will
initiate in the higher terrain of the Appalachians, and move
eastward into the lower elevations during the afternoon. Moderate
deep-layer shear and steep low-level lapse rates, evident on
forecast soundings, will contribute to a marginal wind-damage
threat.
..Broyles.. 06/15/2025
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