SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0254 PM CDT Fri Jun 24 2022
Valid 242000Z - 251200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS
OF NORTH DAKOTA...SOUTH DAKOTA...AND NORTHERN MINNESOTA...
...SUMMARY...
Severe thunderstorms with the potential for widespread damaging wind
gusts, very large hail, and a couple of tornadoes are expected from
the eastern Dakotas into northwestern Minnesota this afternoon into
tonight.
...Discussion...
Only made a minor change by removing low-wind probabilities over
northeast FL in wake of storms moving south-southwest over the
northern and central part of the FL Peninsula. Elsewhere, no change
was made.
..Smith.. 06/24/2022
.PREV DISCUSSION... /ISSUED 1053 AM CDT Fri Jun 24 2022/
...ND/SD/MN...
Morning water vapor imagery shows a broad upper trough across the
northern Rockies today, with an embedded shortwave trough currently
along the MT/WY border. This feature will track into the northern
Plains later today, with large scale forcing for ascent
overspreading parts of the Dakotas. Strong heating across
eastern/central ND and convergence along a surface boundary will
lead to afternoon thunderstorm development from south-central into
northeast ND. Other storms will form by late afternoon to the north
of the boundary across western/central ND as the upper trough
approaches. Forecast soundings suggest strong instability (MLCAPE
of 2500-4500 J/kg) and favorable effective shear for supercell storm
structures capable of very large hail and perhaps a tornado or two.
Storms are expected to develop southward along boundary into central
SD during the evening, with gradual upscale growth into bowing line
segments. This activity will spread into western MN with the risk
of rather widespread damaging winds.
...Northeast WY/northwest SD...
A consensus of 12z model guidance shows a cluster of afternoon
thunderstorms forming over northeast WY and the Black Hills region.
Moisture is more limited in this area, yielding MLCAPE values only
into the 1000 J/kg range. However, steep lapse rates, cool
temperatures aloft (-12C at 500mb), and 30-40 knots of westerly flow
mid-level flow may result in a few supercells capable of hail and
damaging wind gusts.
...Southeast NE and vicinity...
Morning convection has resulted in an outflow boundary extending
from western MO into eastern KS. This boundary is forecast to drift
northward toward the KS/NE border by late afternoon, with forecast
soundings showing relatively large hodographs and strong instability
- posing a conditional risk of severe storms. However, no 12z CAM
guidance shows any thunderstorms forming in this area due to a
relatively warm capping layer. Have therefore removed the SLGT, but
continue to acknowledge the conditional risk of significant severe
weather if a storm can initiate/persist.
...GA/FL...
Numerous afternoon thunderstorms are expected from the FL peninsula
into central GA. A hot, humid, and very unstable air mass is
present in this corridor with dewpoints in the mid/upper 70s and
MLCAPE over 3000 J/kg. Shear is weak, but multicell storms capable
of locally strong/damaging wet microbursts appear possible.
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