Past IEM Features tagged: 2020derecho
Derecho Before and After
23 Aug 2020 01:23 PMImagery from the KCRG-TV webcam in Cedar Rapids on the Mount Mercy campus is shown. The top picture is from August 8th and the bottom picture is from today. The difference between the two images is remarkable. The derecho from August 10th is to blame with some estimates placing over 50% of the trees in Cedar Rapids as damaged or destroyed. The downed trees devastated the power service in the area with a thousand or so customers still without power almost two weeks later.
Voting:
Good: 22
Bad: 0
Tags: 2020derecho webcam
New Iowa Wind Gust Record?
20 Aug 2020 05:36 AMIt has been ten days since the derecho of 10 August 2020 and the cleanup, damage assessment, and power restoration continues. Some new reports from the NWS have come out this week that indicate a new non-tornado wind gust record for the state was set at Atkins,IA (in Benton County) with a gust of 126 MPH reported from a personal weather station. Even higher wind gusts have been estimated based on damage. The featured table presents some of the highest gust reports / estimates from the event. The previous record is believed to be the "Corn Belt Derecho" of 1998 with a report of 123 MPH at Washington IA.
Voting:
Good: 14
Bad: 1
Tags: 2020derecho
Derecho Profile
19 Aug 2020 05:37 AMThe featured chart is a preliminary plot of height profile horizontal wind speed from the ISU "Talltower" facility in Story County (north of Ames). This tower is outfitted with many sensors at various heights and records wind speeds at one second refresh intervals. The chart uses this one second data along with six sensors at various heights to construct a two dimensional analysis of horizontal wind speed during the passage of the most gusty portion of the derecho at that location. Please note that sampling winds at this time resolution more represents gusts than sustained winds. You can see lots of crazy things happen including an initial gust front that rocketed near surface winds to near 90 MPH (11:23 - 11:24 AM) to only subside for a brief moment before the most intense winds arrived. This plot indicates 90+ MPH gusts got very close to the surface with 120+ MPH gusts briefly recorded some 375 feet above ground level.
Voting:
Good: 29
Bad: 0
Tags: 2020derecho talltowers
2020 Derecho Wind Gust Estimate
18 Aug 2020 06:00 AMThe featured map was put together by the National Weather Service and contains a smoothed estimate of wind gusts from the 10 August derecho. This estimate is based on reported damage, observed gusts, RADAR information, and hand analysis. Two swaths of 100+ MPH wind gusts are shown. It is difficult to quantitatively compare this most recent derecho with those of the past to rank which one was the strongest, but for those that continue to feel the impacts a week later, such a ranking does not matter.
Voting:
Good: 12
Bad: 0
Tags: 2020derecho
90 MPH SVR Warning
17 Aug 2020 05:46 AMWhen the National Weather Service issues Severe Thunderstorm (SVR) Warnings, they include tags that denote the forecast max hail size and wind gust. These tags are useful to understand the threat posed by a storm and some communities trigger their outdoor sirens for SVR's with wind tags at or above 70 MPH. The featured chart presents the warning count frequency of the combination of hail and wind gust tags for SVR warnings issued by NWS Des Moines. Each warning contains both a wind gust and hail tag, so they can be compared in this manner and only the tag values at issuance are included in this chart. For the Derecho last Monday (wow, has it been a week already?!?!), NWS Des Moines issued one such warning with a 90 MPH wind gust tag. The first such usage since these tags came into operations.
Voting:
Good: 16
Bad: 1
Tags: 2020derecho
Derecho Power Hit
15 Aug 2020 04:25 PMThe featured graphic is a comparison between the Suomi NPP / VIIRS satellite imagery between July 29th and August 11th. The particular band shown from the satellite is good at showing city lights during clear sky conditions at night time. The damage swath from the August 10th derecho is easily seen with the bullseye hit to Cedar Rapids well shown. Power restoration work is ongoing with full restoration expected to take weeks. See this NASA Website for a better view.
Voting:
Good: 13
Bad: 0
Tags: derecho 2020derecho
75 MPH Gust
14 Aug 2020 06:00 AMThe derecho from Monday should provide fodder for the IEM Daily Feature for the foreseeable future! Today's plot presents one minute interval wind observations from the Des Moines Airport weather station. The chart shows minute by minute readings of wind speed and direction (two minute average of five second samples) and wind gust (peak 5 second sample reading). The quick rise in wind speed is readily seen with the peak value of 50 MPH sustained with gusts to 75 MPH shown. Wind gusts over 50 MPH were observed for over a twenty minute period!
Voting:
Good: 21
Bad: 1
Tags: derecho 2020derecho
The Derecho of 2020
13 Aug 2020 12:58 PMOne of the most significant weather events in Iowa's history happened on Monday, 10 August 2020. A powerful complex of storms bulldozed the state and impacted the major urban centers of Des Moines, Cedar Rapids, Iowa City, and Davenport. The Aqua MODIS satellite data from Tuesday featured in today's map has been making the rounds on the Internet. The map clearly shows the extensive crop damage that happened from west of Des Moines to Davenport. We continue to await a more cloud free day to further see the extent of the crop damage from satellites. Overlain on the map is Local Storm Reports of wind gusts from the National Weather Service.
Tags: derecho 2020derecho