SPC Jun 29, 2020 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0815 PM CDT Sun Jun 28 2020

Valid 290100Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...UPPER MISSISSIPPI VALLEY AND CAROLINAS...

CORRECTED TO FLIP THUNDER LINE IN MAINE

...SUMMARY...
Severe storms with a tornado threat, large hail, and damaging winds
are possible this evening across parts of the northern Plains and
the Upper Mississippi Valley. A wind damage threat will also exist
in parts of the Carolinas and in southern New England early this
evening.

...Northern Plains...
The latest water vapor imagery shows southwest mid-level flow across
the northern Plains with a subtle shortwave trough in the western
Dakotas. Thunderstorms are ongoing near the trough in western South
Dakota. Other storms are ongoing in central and northern North
Dakota on the northern edge of a pocket of strong instability. The
WSR-88D VWP at Bismarck has 0-6 km shear near 35 kt and forecast
soundings show steep mid-level lapse rates. This should be favorable
for isolated supercells with large hail. A wind damage threat will
also be possible with short line segments...see MCD 1041 and 1043. A
tornado can not be ruled out in northern North Dakota early this
evening on the western edge of a 30 to 40 kt low-level speed max.

...Upper Mississippi Valley...
The latest water vapor imagery shows a shortwave trough in the Upper
Mississippi Valley. A band of strong to severe thunderstorms is
ongoing near the trough in eastern Minnesota. The storms are located
along the northern edge of moderate instability where surface
dewpoints are in the lower 70s F. In addition, the RAP shows 0-6 km
shear in the 30 to 40 kt range across parts of southeast Minnesota.
This combined with steep mid-level lapse rates, evident on forecast
soundings, will support isolated supercells with large hail. A
tornado can not be ruled out with any supercell that is dominant.
Wind damage will also be possible along the stronger parts of the
broken line of storms...see MCD 1044. A severe threat with large
hail and wind damage will also be possible further southwest across
southern Minnesota and northern Iowa later this evening where
additional thunderstorms are expected to develop.

...Carolinas...
The latest radar imagery shows a line of strong to severe
thunderstorms from far southern North Carolina extending
west-southwestward across central South Carolina. South of this line
of storms, surface dewpoints are in the lower 70s F with MLCAPE in
the 2000 to 3000 J/kg range. Although deep-layer shear is relatively
weak, the thermodynamic profile should be enough for am isolated
wind damage threat. The wind damage threat could continue for a
couple more hours before instability decreases.

...Southern New England...
The latest water vapor imagery shows an upper-level trough across
western New England. Thunderstorms are ongoing ahead of the trough
from New Hampshire southward into eastern Massachusetts. The airmass
ahead of these storms appears to be weakly unstable which has been
affected by convective outflow. Although the thermodynamic
environment is not as favorable for severe storms, a marginal wind
damage threat will still exist with the stronger multicells for
another hour or two.

..Broyles.. 06/29/2020

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from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_0100.html