SPC AC 061959
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sat Aug 06 2022
Valid 062000Z - 071200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
UPPER MISSISSIPPI VALLEY...
A few severe thunderstorms may develop this afternoon and evening
from the upper Mississippi Valley into the central High Plains.
The primary change with this outlook is to extend the Marginal Risk
slightly westward over central WY, where a couple of strong storms
will be possible in an area south of the Bighorn Mountains.
Otherwise, no changes have been made. See the previous discussion
below for more information.
.PREV DISCUSSION... /ISSUED 1115 AM CDT Sat Aug 06 2022/
Morning satellite imagery shows a canopy of cloud cover associated
with a decaying MCS over MN/WI. The southern edge of clouds extends
from northwest IA into far southern MN and southwest WI. Strong
heating and ample low-level moisture will be present today to the
south of this axis, with MLCAPE values expected to exceed 3000 J/kg
with 20-30 knots of deep-layer mean flow. Most CAM solutions show
scattered thunderstorms developing in this area by late afternoon,
with a few supercell and organized multicell structures possible.
Mid-level temperatures are quite warm and lapse rates are weak,
suggesting that the hail risk will be limited. However, high PW
values and steep low-level lapse rates will promote damaging wind
gusts in the stronger cells. Therefore have added a small SLGT risk
area to parts of the region.
Scattered high-based thunderstorms are expected to develop this
afternoon and evening over the plains of eastern CO/WY and drift
eastward. Forecast soundings show that winds aloft are rather
strong over WY, but thermodynamics will be somewhat marginal.
Isolated supercells will be possible with a risk of hail and
damaging wind gusts, but the forecast coverage of intense storms
appears to be in line with a MRGL category at this time. This will
be re-evaluated at 20z.
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z