Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
89,317
1,896,800
Sioux Falls, SD...Fargo, ND...Sioux City, IA...Grand Island, NE...Moorhead, MN...
SPC AC 010055
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 PM CDT Tue Jun 30 2020
Valid 010100Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...
...SUMMARY...
Thunderstorms associated with wind damage and isolated large hail
will be possible this evening from the eastern Dakotas and far
western Minnesota into eastern Nebraska and western Iowa.
...Central and Northern Plains/Mid Missouri Valley...
Water vapor imagery shows a negatively tilted upper-level trough in
the central and northern High Plains. Southerly mid-level flow
exists over the northern Plains. At the surface, a 1001 mb low is
present in southeast North Dakota with a cold front extending
southward from the low. Surface dewpoints to the east of the front
are in the 70s F which is contributing to extreme instability with
MLCAPE in the 4000 to 5500 J/kg range, according to the RAP. As the
line moves eastward across the instability corridor this evening,
MCS development appears likely. The MCS will move eastward across
the eastern Dakotas and into far western Minnesota by late evening.
Although deep-layer shear is weak across much of the instability
corridor, stronger shear is present near the front. RAP analysis
suggests that 0-6 km shear is in the 20 to 30 kt range near the
front, where most of the strong convection is ongoing. This combined
with enhanced low-level convergence along a north-to south boundary
will favor squall-line development. Wind damage will be greatest
threat with the squall-line although isolated large hail will be
possible in the more intense parts of the line as well.
...Southern Plains...
The latest surface analysis shows a trough across west Texas. To the
east of the surface trough, dewpoints generally range from 65 to 70
F. This is contributing to moderate instability across much of
west-central Texas. Widely scattered thunderstorms are ongoing to
the east of the surface trough where low-level convergence is
locally maximized. Although deep-layer shear is weak across most of
west and central Texas, the instability and steep low-level lapse
rates may be enough for a marginal wind damage and hail threat early
this evening.
...Tennessee Valley...
The latest radar imagery shows scattered thunderstorms from western
Tennessee southeastward into northern Alabama. This convection is
located on the northeastern edge of a moderately unstable airmass
with the RAP estimating MLCAPE in the 2000 to 3500 J/kg. The storms
will continue to move southeastward along a relatively tight
instability gradient. Although deep-layer shear is weak across the
Tennessee Valley, low-level lapse rates are steep. This may be
enough for marginally severe wind gusts with short multicell line
segments.
..Broyles.. 07/01/2020
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