Alert archive / Iowa / Severe Thunderstorm Warnings in 2020
Severe Thunderstorm Warning 98, NWS Omaha, NE
NWS Omaha, NE issued this severe thunderstorm warning at Jun 26, 2020, 6:32 PM CDT for Mills County, Montgomery County, Pottawattamie County, Iowa. It was in force for 28 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jun 26, 2020, 6:32 PM CDT (23:32 UTC)
- Expired
- Jun 26, 2020, 7:00 PM CDT
- In force
- 28 min
- Issued by
- NWS Omaha, NE
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 50.0 mph
Counties Mills County, IA, Montgomery County, IA, Pottawattamie County, IA
The radar
The Omaha radar (KOAX), 80 km from the middle of the area, began a volume at 23:31 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Topeka, KS (KTOP), launched 12:00Z, 11.5 hours before the alert went out and 238 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 113 J/kg
- Mixed-layer CIN
- -475 J/kg
- Mixed-layer LCL
- 1770 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 153 m²/s²
- 0-3 km storm-relative helicity
- 119 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Omaha, NE wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 26, 6:19 PM CDT, 13 minutes earlier.
Area forecast discussion, Jun 26, 6:19 PM CDT, 13 minutes before
Area Forecast Discussion National Weather Service Omaha/Valley NE 619 PM CDT Fri Jun 26 2020 ...Updated Aviation Forecast Discussion... .DISCUSSION... Issued at 236 PM CDT Fri Jun 26 2020 Weak frontal boundary at 2 pm was located just south of Lincoln extending east to near Plattsmouth, then northeast toward Atlantic. A few showers/sprinkles had developed along the front before noon, and this trend continues into mid afternoon. No lightning has been observed thus far. The boundary will continue to be the focus for a few showers, and possible thunderstorms late this afternoon as the front continues to slowly move toward the NE/KS border by mid to late evening. CAMs suggest a storm or two may pop along the front by about 5-7 pm, with scattered coverage through the remainder of the evening. All of this activity will be south of I80, with areas to the north likely remaining dry tonight. SPC has our southern forecast area in a slight risk for wind and hail and this seems reasonable. After midnight, there remains a threat for scattered storms across southeast NE and southwest IA. And again, some of these overnight storms could have some hail, and it's possible that a few locations get more than one or two storms, thus locally heavy rainfall will also be possible, but flooding is not expected. Previous forecasts indicated that Saturday would be mainly dry, but models now appear to be latching onto a weak wave moving out of the central Rockies. This is also what may help to energize the overnight activity, but this wave could also still be present Saturday, to at least bring a slight chance of showers/storms along and east of the Missouri River. Meanwhile, another upper wave moving out of the Rockies could bring more storm chances to the area Saturday night into Sunday. This may help push the previously mentioned frontal boundary north, and thus there's at least a marginal risk of a stronger storm south of I80 Saturday night as indicated by a few of the CAMs, but confidence is not great. After upper 80s on Saturday, highs head back into the lower 90s probably through at least Wednesday. With dewpoints heading back into the lower 70s, afternoon heat index values increase to 96 to 103, and while not hot enough for a heat advisory, we're probably looking at several very muggy days with uncomfortable humidity. There will also be occasional shower/storm chances in there, and while continuous rain isn't expected, there will be at least a daily 20-40% chance somewhere in our forecast every day next week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 617 PM CDT Fri Jun 26 2020 VFR conditions will prevail for the TAF period. Rain and a possible thunderstorm may pop up in the vicinity of KLNK but should not impact the terminal. A weak frontal boundary has passed through the area and may retreat northward. Due to this, winds will be light and variable for most of the TAF period. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && DISCUSSION...DeWald AVIATION...Fajman
Hazardous weather outlook, Jun 26, 3:32 PM CDT, 3 hours before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>The office that day
Everything else NWS Omaha, NE issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 25, 11:18 PM CDT | Special Weather Statement | OAX | Knox | 27 min |
| Jun 26, 6:56 PM CDT | Severe Thunderstorm Warning | OAX | Montgomery, Pottawattamie | 20 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 2020Every severe thunderstorm warning in 2020
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.