Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
5 %
19,547
3,565,211
Minneapolis, MN...St. Paul, MN...Bloomington, MN...Plymouth, MN...Brooklyn Park, MN...
2 %
58,823
2,583,108
Fort Collins, CO...Rochester, MN...Greeley, CO...Duluth, MN...Loveland, CO...
Probabilistic Damaging Wind Graphic
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 %
113,422
15,367,265
Indianapolis, IN...Denver, CO...Colorado Springs, CO...Minneapolis, MN...St. Louis, MO...
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
45,788
4,253,487
Denver, CO...Colorado Springs, CO...Aurora, CO...Lakewood, CO...Fort Collins, CO...
5 %
315,315
28,313,549
Chicago, IL...Kansas City, MO...Minneapolis, MN...St. Louis, MO...St. Paul, MN...
SPC AC 211626
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1126 AM CDT Tue Jul 21 2020
Valid 211630Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL HIGH PLAINS...AND PORTIONS OF THE MIDDLE AND UPPER
MISSISSIPPI VALLEY...
...SUMMARY...
Severe thunderstorms are possible today across parts of the central
High Plains, and Middle and Upper Mississippi Valley regions.
...CO/WY...
Weak flow and upper ridging dominate the weather across the southern
United States today, with marginally strong west-northwesterly flow
over the central/northern High Plains. Clear skies are noted over
most of this area, with a moist boundary-layer over eastern WY/CO
where dewpoints are in the low/mid 50s. Strong heating will yield
afternoon MLCAPE values around 1500 J/kg from east-central CO
northward into eastern WY. It appears likely that scattered
thunderstorms will form this afternoon over the foothills and spread
eastward into the adjacent plains. Coverage of storms appears
highest over southeast WY, with more isolated cells farther south
into CO where a weak cap might limit storms. Forecast soundings
indicate steep mid-level lapse rates and sufficient vertical shear
for large hail in the strongest cells. A deeply-mixed boundary
layer will also support damaging wind gusts.
...MO/IL/IN...
Multiple remnant MCVs and outflow boundaries are present today over
the mid MS Valley. Model guidance is not handling the mesoscale
details very well, and pockets of cloud cover/precipitation further
reduce confidence in the location/intensity of thunderstorm clusters
later today. Nevertheless, a band of stronger 3-6km flow over MO is
expected to overspread the SLGT risk area this afternoon, helping to
organize any storms that can develop. Locally damaging winds would
be the main threat with this activity.
...MN/WI...
A weak surface over central MN will track slowly eastward today
toward northern WI. Forecast soundings in the warm-sector of the
low show favorable low-level shear profiles for rotating storms
capable of damaging winds or a tornado or two. However,
considerable cloud cover and affects of morning precipitation are
lessening confidence in overall severe threat. Will maintain the
SLGT risk with some adjustments in case clearing from the west
results in greater destabilization than currently anticipated.
...Mid Atlantic Region...
Hot/humid conditions over parts of PA/MD/VA/NC will lead to
scattered afternoon thunderstorms. Weak flow aloft indicates that
storms will likely be disorganized, but localized gusty/damaging
winds are possible in the stronger downdrafts.
..Hart/Moore.. 07/21/2020
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