IEM Daily Feature
Tuesday, 27 November 2018
Tuesday, 27 November 2018
Meeting Blizzard Criteria
Posted: 27 Nov 2018 05:28 AM
The NWS issues a Blizzard Warning when falling and/or blowing snow combines with
strong winds to create dangerously low visibility over at least a three hour period. The
threshold for wind is frequent gusts over 30 knots and visibility is frequently less than a
quarter mile. The featured chart looks at meeting that criteria based on automated airport
weather stations that were under the Blizzard Warning. The three panels uses different
methodologies to summarize the best (closest to meeting criteria) values based on wind
speed and visibility. The first panel uses a strict requirement on all reported winds and
visibility, the second panel takes the three hour average and the third panel uses the
median value over the three hour period. Verifying blizzards with automated weather
station data is difficult, but so is it for a human as we tend to not want to stay outside for
three hour stretches in very bad winter weather.
Voting:
Good = 17
Bad = 1
Tags: blizzard
Voting:
Good = 17
Bad = 1
Tags: blizzard