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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 507
NWS Storm Prediction Center Norman OK
210 PM CDT Mon Sep 20 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Central and Eastern Iowa
* Effective this Monday afternoon and evening from 210 PM until
1000 PM CDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Scattered large hail events to 1.5 inches in diameter possible
A tornado or two possible
SUMMARY...Thunderstorms are expected to develop rapidly this
afternoon along a cold front moving into southeast Minnesota and
central Iowa. These storms will track quickly eastward across the
watch area, posing a risk of damaging winds and hail. An isolated
tornado or two is also possible over western Wisconsin later this
The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 40 miles north of Eau
Claire WI to 25 miles east of Lamoni IA. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 450. Mean storm motion vector