St. Louis, MO...Evansville, IN...St. Charles, MO...Jonesboro, AR...Owensboro, KY...
Probabilistic Tornado Graphic
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
2 %
12,420
2,555,940
St. Louis, MO...St. Charles, MO...Florissant, MO...Chesterfield, MO...Belleville, IL...
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
5 %
67,482
6,097,362
St. Louis, MO...Evansville, IN...St. Charles, MO...Jonesboro, AR...Owensboro, KY...
Probabilistic Large Hail Graphic
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
No Risk Areas Forecast
SPC AC 101237
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0737 AM CDT Tue Oct 10 2017
Valid 101300Z - 111200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING ACROSS THE MIDDLE MS AND LOWER OH VALLEYS...
...SUMMARY...
A marginal severe threat with strong wind gusts is forecast to
develop this afternoon across the mid Mississippi Valley region and
spread east into the lower Ohio Valley during the evening.
...Mid MS Valley and lower OH Valley this afternoon/evening...
No substantial changes to the previous outlook. A midlevel
shortwave trough over KS/OK this morning will move
east-northeastward to the middle MS Valley by this evening, and the
OH Valley overnight as the trough weakens slowly. An associated
diffuse surface low in southern MO will move toward southern/central
IL by this evening, as a trailing cold front progresses eastward
across the lower MS Valley. A moist warm sector, with
boundary-layer dewpoints in the upper 60s to lower 70s, is present
south of a baroclinic zone across the OH Valley.
In the wake of some morning convection, the rich low-level moisture
and stronger surface heating near the MS River will boost MLCAPE to
the 1000-1500 J/kg range, though midlevel lapse rates will remain
modest at best. A concurrent increase in deep-layer vertical shear
with the approach of the midlevel trough will support the
development of organized clusters and low-end supercells near the
surface low and along the trailing cold front this afternoon. Warm
midlevel temperatures and the modest lapse rates (near 6 C/km) will
tend to limit the threat for hail. Given the already weak surface
low and no expected deepening, low-level shear in the warm sector is
expected to be marginal for tornadic supercells. Though a
brief/weak tornado cannot be ruled out, isolated strong/damaging
outflow gusts will be the main concern this afternoon/evening.
..Thompson/Peters.. 10/10/2017
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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