Des Moines, IA...Cedar Rapids, IA...Davenport, IA...Sioux City, IA...Iowa City, IA...
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
No Risk Areas Forecast
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 %
39,887
2,505,464
Des Moines, IA...Cedar Rapids, IA...Davenport, IA...Sioux City, IA...Iowa City, IA...
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
5 %
40,628
2,524,706
Des Moines, IA...Cedar Rapids, IA...Davenport, IA...Sioux City, IA...Iowa City, IA...
SPC AC 181600
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1100 AM CDT Tue Sep 18 2018
Valid 181630Z - 191200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE UPPER MIDWEST...
...SUMMARY...
Isolated hail and damaging wind gusts are possible today over parts
of the Upper Midwest.
...NE/IA/IL...
A persistent cluster of thunderstorms is affecting much of northern
IA and adjacent regions this morning, with the leading-edge outflow
surging southward across eastern IA. Much of this region has been
stabilized by the convection, leaving a corridor from eastern NE
into northwest IL where sufficient heating is possible later today.
This axis may see storm intensification by mid/late afternoon, with
the strongest cells capable of hail or locally damaging wind gusts.
Present indications are that the severe risk will remain isolated
and marginal in nature.
..Hart/Darrow.. 09/18/2018
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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